U.S. patent application number 16/446504 was filed with the patent office on 2020-12-24 for engine oil pressure regulation system.
The applicant listed for this patent is Ford Global Technologies, LLC. Invention is credited to David Simon, Abhijyoth Vempati.
Application Number | 20200400049 16/446504 |
Document ID | / |
Family ID | 1000005261143 |
Filed Date | 2020-12-24 |
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United States Patent
Application |
20200400049 |
Kind Code |
A1 |
Vempati; Abhijyoth ; et
al. |
December 24, 2020 |
ENGINE OIL PRESSURE REGULATION SYSTEM
Abstract
Methods and systems are provided for a lubricant system for an
engine. In one example, the system includes external delivery lines
coupling an oil reservoir of the engine to a plurality of cylinder
head oil galleries, the engine also having internal oil passages.
An amount of hydraulic fluid delivered via the external delivery
lines is controlled by a pressure control valve having a vent
line.
Inventors: |
Vempati; Abhijyoth;
(Northville, MI) ; Simon; David; (Plymouth,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ford Global Technologies, LLC |
Dearborn |
MI |
US |
|
|
Family ID: |
1000005261143 |
Appl. No.: |
16/446504 |
Filed: |
June 19, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K 17/003 20130101;
F01M 1/16 20130101; F16K 17/085 20130101 |
International
Class: |
F01M 1/16 20060101
F01M001/16; F16K 17/00 20060101 F16K017/00 |
Claims
1. A system comprising: delivery lines, arranged external to an
engine, the delivery lines coupling an oil reservoir of the engine
to a plurality of cylinder head oil galleries along an external
surface of the engine, the oil reservoir also coupled to the
plurality of cylinder head oil galleries via oil passages internal
to the engine; a pressure control valve, arranged external to the
engine, for controlling an amount of hydraulic fluid delivered
through the delivery lines, each of the delivery lines coupled to
the pressure control valve; and an external vent line configured to
couple the pressure control valve to the oil reservoir when a
pressure in the cylinder head oil galleries rises above a threshold
pressure, and when the pressure control valve is degraded and stuck
open, wherein the threshold pressure is set at the pressure control
valve.
2. The system of claim 1, wherein the delivery lines include an oil
feed line flowing oil from the oil reservoir to the pressure
control valve with a first amount of hydraulic pressure.
3. The system of claim 2, wherein the delivery lines include
external passages flowing oil from the pressure control valve to
the each of the plurality of cylinder head oil galleries with a
second amount of hydraulic pressure, the second amount lower than
the first amount of hydraulic pressure.
4. The system of claim 3 wherein the external passages each include
an end configured to couple to a respective cylinder head oil
gallery through a respective inlet opening in a wall of the
engine.
5. The system of claim 1, wherein the pressure control valve has an
inlet positioned at a bottom side of the pressure control valve,
outlets positioned at oppositely arranged sides of the pressure
control valve, and a mechanism for adjusting oil flow through the
pressure control valve positioned at a top side of the pressure
control valve.
6. The system of claim 5, wherein the vent line is coupled to the
pressure control valve at the top side of a pressure control
device, adjacent to the mechanism for adjusting oil flow through
the pressure control device.
7. The system of claim 1, wherein the pressure control valve is
mounted to the external surface of the engine at a side opposite of
a location of an oil filter of the engine.
8. The system of claim 7, wherein the oil flows from the pressure
control valve to the oil reservoir through the vent line.
9. The system of claim 1, wherein the oil delivered to the
plurality of cylinder head oil galleries provides hydraulic
pressure in addition to hydraulic pressure provided by the oil
passages internal to an engine block.
10. A lubricant system for an engine, comprising; an oil sump
arranged below an engine block; a cylinder head arranged above the
engine block; an internal passage, internal to the engine block and
coupling the oil sump to cylinder head oil galleries of the engine;
one or more external passages, external to both the engine block
and the cylinder head, also coupling the oil sump to the cylinder
head oil galleries, the one or more external passages separate from
the internal passage; and a pressure control valve coupled to each
of the one or more external passages, the pressure control valve
having a vent line configured to flow oil to the oil sump when a
pressure in the cylinder head oil galleries rises above a threshold
pressure, wherein the threshold pressure is set at the pressure
control valve and wherein, when the pressure control valve is
degraded and stuck open, oil flows from the pressure control valve
to the oil sump through the vent line.
11. The lubricant system of claim 10, wherein the one or more
external passages flow oil to the cylinder head oil galleries
simultaneous with oil flowing to the cylinder head oil galleries
from the internal passage.
12. The lubricant system of claim 10, wherein the one or more
external passages includes a feed line coupled at a first end to an
oil filter, the oil filter arranged between the feed line and the
oil sump, and coupled at a second end to the pressure control valve
and wherein the feed line is configured to deliver oil from the oil
sump to the pressure control valve via the oil filter.
13. The lubricant system of claim 12, wherein the one or more
external passages includes a first passage delivering oil from the
pressure control valve to a first set of galleries of the cylinder
head oil galleries and a second passage delivering oil from the
pressure control valve to a second set of galleries of the cylinder
head oil galleries.
14. The lubricant system of claim 13, wherein a hydraulic pressure
in the feed line is higher than a hydraulic pressure in each of the
first and second passages.
15. The lubricant system of claim 14, wherein the pressure control
valve is configured to maintain a uniform hydraulic pressure to the
first and second passages by adjusting an amount of oil flowing
through the pressure control valve to the first and second
passages.
16. (canceled)
17. A kit for an engine, comprising; a pressure control valve; a
feed line coupled to an inlet of the pressure control valve;
passages coupled to outlets of the pressure control valve at first
ends of each of the passages and configured to couple to oil
galleries in a cylinder head of the engine at second ends of each
of the passages; and a vent line connected to the pressure control
valve and configured to vent oil from the oil galleries in the
cylinder head when a hydraulic pressure in the oil galleries
increases above a threshold pressure, wherein the threshold
pressure is set at the pressure control valve and wherein, when the
pressure control valve is degraded and stuck open, oil flows from
the pressure control valve to the oil sump through the vent
line.
18. The kit of claim 17, wherein the pressure control valve, the
feed line, the passages, and the vent line are all configured to be
positioned external to the engine.
19. The kit of claim 17, wherein the kit is configured to be
coupled to a wet oil sump of the engine.
20. The kit of claim 17, wherein the kit is configured to be
coupled to a dry oil sump of the engine.
Description
FIELD
[0001] The present description relates generally to methods and
systems for controlling oil pressure in an engine.
BACKGROUND/SUMMARY
[0002] An internal combustion engine includes various moving
components, the motion of the components enabling engine operations
and providing torque to propel the vehicle. The moving components
may be lubricated with oil to reduce friction of the moving
components. For example, a cylinder head of the engine may include
one or more internal passages flowing oil from an oil sump or
reservoir to oil galleries in the cylinder head. The oil galleries
may deliver oil to cylinder head components such as a camshaft as
well as parts coupled to the camshaft. The oil may form films
between adjacent moving parts, allowing the components to move with
reduced friction and thereby increasing a lifetime of the
components.
[0003] Consistent cylinder head oil pressure may be difficult to
maintain due to variations in oil temperature, slosh, fuel dilution
of the oil, aeration, etc. The engine may experience a wide range
of operating conditions that may lead to fluctuating oil pressure
in the cylinder head, which may adversely affect engine operation.
For example, inconsistent cylinder head oil pressure may cause
variations in cam lobe operation and valve actuation, resulting in
poor engine performance.
[0004] Attempts to address inconsistent cylinder head oil pressure
include equipping an engine lubricant system with a device to
control oil pressure. One example approach is shown in Chinese
Patent No. 101818669. Therein, an oil supply system for an engine
includes a distribution network coupled to an oil pump. A main
pressure reducing valve is connected to the distribution network
downstream of the oil pump and determines a maximum pressure
setting of the distribution network. An auxiliary pressure reducing
valve is coupled to the distribution network downstream of the main
pressure reducing valve and configured to return oil from the
distribution network to an oil reservoir of the oil supply system.
The auxiliary pressure reducing valve may operate in a first mode
in which the auxiliary pressure reducing valve actively controls
the pressure in the distribution network, reducing the pressure to
a first pressure that is lower than the main pressure reducing
valve. The first operating mode may enable oil pressure to be
reduced to provide fuel economy benefits when high oil pressure and
flow is not demanded. In a second operating mode, which may be a
normal operating mode, the auxiliary pressure reducing valve
adjusts the distribution network pressure to a second pressure that
is higher than the first pressure, e.g., similar to the maximum
pressure set by the main pressure reducing valve.
[0005] However, the inventors herein have recognized potential
issues with such systems. As one example, oil flow may be high
during operation of the auxiliary pressure reducing valve in the
normal, second mode, leading to parasitic losses when the auxiliary
pressure reducing valve is not operating in the first mode. In
addition, the oil pressure may overshoot under cold oil conditions,
causing a hydraulic lash adjuster pump-up. Furthermore, the use of
pressure reducing valves may not address variations in cylinder
head oil pressure which may cause valvetrain instability.
[0006] In one example, the issues described above may be addressed
by a method for a system including delivery lines, arranged
external to an engine, the delivery lines coupling an oil reservoir
of the engine to a plurality of cylinder head oil galleries along
an external surface of the engine, the oil reservoir also coupled
to the plurality of cylinder head oil galleries via oil passages
internal to the engine, a pressure control valve, arranged external
to the engine, for controlling an amount of hydraulic fluid
delivered through the delivery lines, each of the delivery lines
coupled to the pressure control valve, and an external vent line
configured to couple the pressure control valve to the oil
reservoir when the pressure control valve is degraded. In this way,
oil pressure may be supplied to the cylinder head in addition to
oil supplied by internal passages of the engine to both increase
the oil pressure and maintain a uniform oil pressure across all
engine cylinder head oil galleries.
[0007] As one example, the external delivery lines include a feed
line flowing the hydraulic fluid from the oil reservoir to the
pressure control valve and external passages flowing the hydraulic
fluid from the pressure control valve to the cylinder head oil
galleries. The flow of hydraulic fluid to the cylinder head oil
galleries supplements hydraulic pressure in the oil galleries
provided by the internal oil passages and the hydraulic pressure in
the oil galleries is maintained consistent by the pressure control
valve. In this way, a single device may be used to efficiently
control cylinder head oil pressure. The device may accommodate a
wide range of engine operating conditions with reduced parasitic
losses and continue controlling cylinder head oil pressure even if
there is degradation in the pressure control valve.
[0008] It should be understood that the summary above is provided
to introduce in simplified form a selection of concepts that are
further described in the detailed description. It is not meant to
identify key or essential features of the claimed subject matter,
the scope of which is defined uniquely by the claims that follow
the detailed description. Furthermore, the claimed subject matter
is not limited to implementations that solve any disadvantages
noted above or in any part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a schematic diagram of an engine which may be
lubricated by a lubricant system.
[0010] FIG. 2 shows a schematic diagram of an engine lubricant
system.
[0011] FIG. 3 shows a flow of oil within an engine through oil
galleries in a cylinder head and a block of the engine.
[0012] FIG. 4 shows a rear view of an example of an engine adapted
with a pressure regulation system feeding oil to a cylinder head of
the engine via external oil passages and a pressure control
valve.
[0013] FIG. 5 shows a left side view of the engine of FIG. 4.
[0014] FIG. 6 shows a zoomed-in view of a coupling of the external
oil passages to the cylinder head of the engine of FIG. 4.
[0015] FIG. 7 shows a zoomed-in view of the pressure control valve
of the pressure regulation system shown in FIG. 4.
[0016] FIG. 8 shows example operations of components of the
pressure regulation system during engine operation.
[0017] FIGS. 4-7 are shown approximately to scale
DETAILED DESCRIPTION
[0018] The following description relates to systems and methods for
controlling oil pressure in a cylinder head of an engine. The
cylinder head and other components of the engine may be lubricated
by a lubricant system circulating oil through the engine. An
example of an engine is shown in FIG. 1, the engine relying on oil
flow to a cylinder head to reduce friction between moving
components in the cylinder head. An example of an engine lubricant
system is shown in FIG. 2, depicting a general pathway of oil
delivery to various components of the engine. An internal pathway
of oil delivery through the engine is further shown in an example
of an engine in FIG. 3, including oil flow through cylinder head
oil galleries. In order to maintain a uniform oil pressure in the
cylinder head, the oil galleries may each be coupled to a pressure
control valve of a pressure regulation system, the pressure
regulation system arranged external to the cylinder head and
configured to deliver additional oil to specific areas of the
engine and control the oil pressure in the specific areas. An
example of an engine adapted with the pressure regulation system is
shown in FIGS. 4-7, illustrating oil passages external to the
engine as well as a vent line coupled to the pressure control
valve. Example operations of the pressure regulation system are
depicted in FIG. 8.
[0019] Turning now to the figures, FIG. 1 depicts an example of a
vehicle 5 including a combustion chamber or cylinder of internal
combustion engine 10. Engine 10 may be controlled at least
partially by a control system including controller 12 and by input
from a vehicle operator 130 via an input device 132. In this
example, input device 132 includes an accelerator pedal and a pedal
position sensor 134 for generating a proportional pedal position
signal PP. Cylinder (herein also "combustion chamber") 14 of engine
10 may include combustion chamber walls 136 with piston 138
positioned therein and a cylinder head (e.g., head) 90 positioned
above cylinder 14. Piston 138 may be coupled to crankshaft 140 so
that reciprocating motion of the piston is translated into
rotational motion of the crankshaft. Crankshaft 140 may be coupled
to at least one drive wheel of the passenger vehicle via a
transmission system. Further, a starter motor (not shown) may be
coupled to crankshaft 140 via a flywheel to enable a starting
operation of engine 10.
[0020] Cylinder 14 can receive intake air via a series of intake
air passages 142, 144, and 146 (which may be referred to herein as
intake lines). In some examples, intake air passage 146 may be one
of a plurality of passages of an intake manifold of the engine 10,
with each passage of the plurality of passages being coupled to a
separate cylinder of the engine 10. Intake air passage 142 may be
the most upstream intake air passage of the series of intake air
passages shown in FIG. 1, and may include an airbox 92 at an inlet
of the intake air passage 142.
[0021] In some examples, one or more of the intake passages may
include a boosting device such as a turbocharger or a supercharger.
For example, FIG. 1 shows engine 10 configured with a turbocharger
175 including a compressor 174 arranged between intake passages 142
and 144, and an exhaust turbine 176 arranged along exhaust passage
148. Compressor 174 may be at least partially powered by exhaust
turbine 176 via a shaft 180 where the boosting device is configured
as a turbocharger. A throttle 162 including a throttle plate 164
may be provided along an intake passage of the engine for varying
the flow rate and/or pressure of intake air provided to the engine
cylinders. For example, throttle 162 may be positioned downstream
of compressor 174 as shown in FIG. 1, or alternatively may be
provided upstream of compressor 174.
[0022] Cylinder 14 may be one combustion chamber amongst several
combustion chambers included in an engine block 147, which may also
include a crank case enclosing the combustion chambers and the
crankshaft 140. The engine 10 may rely on circulation of a
hydraulic fluid, such as oil, through a lubrication system 95,
which flows oil from an oil reservoir 91 to various engine
components, such as the crankshaft 140 and the engine block 147 and
the head 90 to lubricate moving parts and reduce friction. Flow of
oil through the engine via a lubricant system such as the
lubrication system 95 is described further below with reference to
FIGS. 2 and 3.
[0023] A first portion of oil may be pumped to the engine block 147
via a first set of internal passages 97 in the engine block 147 and
a second portion of oil may be pumped to the head 90 via a second
set of internal passages 99 in the head 90 by an engine oil pump
(not shown in FIG. 1) from the oil reservoir 91. In some examples,
the oil reservoir 91 may be a wet sump in the engine block 147,
configured to collect oil draining from lubricated components of
the engine block 147 and the head 90. In other examples, the oil
reservoir 91 may be positioned internal or external to the engine
block 147 and coupled to a dry sump in the engine block 147 that
collects oil and continually feeds the oil to the oil reservoir
91.
[0024] The lubrication system 95 may include, in some examples, a
pressure control valve 93 positioned between the oil reservoir 91
and the head 90 and arranged in a set of external oil passages 101.
The pressure control valve 93 may be coupled to oil galleries of
the head 90 by the set of external oil passages 101 and an oil
pressure amongst the oil galleries of the head 90 may be maintained
uniform by the pressure control valve 93. The set of external oil
passages 101 may deliver oil to the oil galleries in addition to
the oil delivered to the oil galleries via the second set of
internal passages 99 of the head 90. Further details of the
pressure control valve 93 and the set of external oil passage 101
are provided below with reference to FIGS. 4-8.
[0025] Exhaust passage 148 can receive exhaust gases from other
cylinders of engine 10 in addition to cylinder 14. Exhaust gas
sensor 128 is shown coupled to exhaust passage 148 upstream of
emission control device 178. Sensor 128 may be selected from among
various suitable sensors for providing an indication of exhaust gas
air/fuel ratio such as a linear oxygen sensor or UEGO (universal or
wide-range exhaust gas oxygen), a two-state oxygen sensor or EGO
(as depicted), a HEGO (heated EGO), a NOx, HC, or CO sensor, for
example. Emission control device 178 may be a three way catalyst
(TWC), NOx trap, various other emission control devices, or
combinations thereof.
[0026] Each cylinder of engine 10 may include one or more intake
valves and one or more exhaust valves. For example, cylinder 14 is
shown including at least one intake poppet valve 150 and at least
one exhaust poppet valve 156 located at an upper region of cylinder
14. In some examples, each cylinder of engine 10, including
cylinder 14, may include at least two intake poppet valves and at
least two exhaust poppet valves located at an upper region of the
cylinder.
[0027] Intake valve 150 may be controlled by controller 12 via
actuator 152. Similarly, exhaust valve 156 may be controlled by
controller 12 via actuator 154. During some conditions, controller
12 may vary the signals provided to actuators 152 and 154 to
control the opening and closing of the respective intake and
exhaust valves. The position of intake valve 150 and exhaust valve
156 may be determined by respective valve position sensors (not
shown). The valve actuators may be of the electric valve actuation
type or cam actuation type, or a combination thereof.
[0028] Cylinder 14 can have a compression ratio, which is the ratio
of volumes when piston 138 is at a maximum volume position to a
minimum volume position. In some examples, these positions may
correspond to bottom dead center and top dead center but may
correspond to other piston positions when the engine is configured
with offset cranks. In one example, the compression ratio is in the
range of 9:1 to 10:1. However, in some examples where different
fuels are used, the compression ratio may be increased. This may
happen, for example, when higher octane fuels or fuels with higher
latent enthalpy of vaporization are used. The compression ratio may
also be increased if direct injection is used due to its effect on
engine knock.
[0029] In some examples, each cylinder of engine 10 may include a
spark plug 192 for initiating combustion. Ignition system 190 can
provide an ignition spark to combustion chamber 14 via spark plug
192 in response to spark advance signal SA from controller 12,
under select operating modes. However, in some embodiments, spark
plug 192 may be omitted, such as where engine 10 may initiate
combustion by auto-ignition or by injection of fuel as may be the
case with some diesel engines.
[0030] In some examples, each cylinder of engine 10 may be
configured with one or more fuel injectors for providing fuel
thereto. As a non-limiting example, cylinder 14 is shown including
two fuel injectors 166 and 170. Fuel injectors 166 and 170 may be
configured to deliver fuel received from fuel system 8. Fuel system
8 may include one or more fuel tanks, fuel pumps, and fuel rails.
Fuel injector 166 is shown coupled directly to cylinder 14 for
injecting fuel directly in response to a first signal 151 received
from controller 12 via electronic driver 168. In this manner, fuel
injector 166 provides what is known as direct injection (hereafter
referred to as "DI") of fuel into combustion cylinder 14. While
FIG. 1 shows injector 166 positioned to one side of cylinder 14, it
may alternatively be located overhead of the piston, such as near
the position of spark plug 192. Such a position may improve mixing
and combustion when operating the engine with an alcohol-based fuel
due to the lower volatility of some alcohol-based fuels.
Alternatively, the injector may be located overhead and near the
intake valve to improve mixing. Fuel may be delivered to fuel
injector 166 from the fuel tank of fuel system 8 via a high
pressure fuel pump, and a fuel rail. Further, the fuel tank may
have a pressure transducer providing a signal to controller 12.
[0031] Fuel injector 170 is shown arranged in intake passage 146,
rather than in cylinder 14, in a configuration that provides what
is known as port injection of fuel (hereafter referred to as "PFI")
into the intake port upstream of cylinder 14. Fuel injector 170 may
inject fuel, received from fuel system 8, in response to a second
signal 153 received from controller 12 via electronic driver 171.
Note that a single driver 168 or 171 may be used for both fuel
injection systems, or multiple drivers, for example driver 168 for
fuel injector 166 and driver 171 for fuel injector 170, may be
used, as depicted.
[0032] In an alternate example, each of fuel injectors 166 and 170
may be configured as direct fuel injectors for injecting fuel
directly into cylinder 14. In still another example, each of fuel
injectors 166 and 170 may be configured as port fuel injectors for
injecting fuel upstream of intake valve 150. In yet other examples,
cylinder 14 may include only a single fuel injector that is
configured to receive different fuels from the fuel systems in
varying relative amounts as a fuel mixture, and is further
configured to inject this fuel mixture either directly into the
cylinder as a direct fuel injector or upstream of the intake valves
as a port fuel injector. As such, it should be appreciated that the
fuel systems described herein should not be limited by the
particular fuel injector configurations described herein by way of
example.
[0033] Fuel may be delivered by both injectors to the cylinder
during a single cycle of the cylinder. For example, each injector
may deliver a portion of a total fuel injection that is combusted
in cylinder 14. Further, the distribution and/or relative amount of
fuel delivered from each injector may vary with operating
conditions, such as engine load, knock, and exhaust temperature,
such as described herein below. The port injected fuel may be
delivered during an open intake valve event, closed intake valve
event (e.g., substantially before the intake stroke), as well as
during both open and closed intake valve operation. Similarly,
directly injected fuel may be delivered during an intake stroke, as
well as partly during a previous exhaust stroke, during the intake
stroke, and partly during the compression stroke, for example. As
such, even for a single combustion event, injected fuel may be
injected at different timings from the port and direct injector.
Furthermore, for a single combustion event, multiple injections of
the delivered fuel may be performed per cycle. The multiple
injections may be performed during the compression stroke, intake
stroke, or any appropriate combination thereof.
[0034] Fuel injectors 166 and 170 may have different
characteristics. These include differences in size, for example,
one injector may have a larger injection hole than the other. Other
differences include, but are not limited to, different spray
angles, different operating temperatures, different targeting,
different injection timing, different spray characteristics,
different locations etc. Moreover, depending on the distribution
ratio of injected fuel among injectors 170 and 166, different
effects may be achieved.
[0035] Fuel tanks in fuel system 8 may hold fuels of different fuel
types, such as fuels with different fuel qualities and different
fuel compositions. The differences may include different alcohol
content, different water content, different octane, different heats
of vaporization, different fuel blends, and/or combinations thereof
etc. One example of fuels with different heats of vaporization
could include gasoline as a first fuel type with a lower heat of
vaporization and ethanol as a second fuel type with a greater heat
of vaporization. In another example, the engine may use gasoline as
a first fuel type and an alcohol containing fuel blend such as E85
(which is approximately 85% ethanol and 15% gasoline) or M85 (which
is approximately 85% methanol and 15% gasoline) as a second fuel
type. Other feasible substances include water, methanol, a mixture
of alcohol and water, a mixture of water and methanol, a mixture of
alcohols, etc.
[0036] In still another example, both fuels may be alcohol blends
with varying alcohol composition wherein the first fuel type may be
a gasoline alcohol blend with a lower concentration of alcohol,
such as Eli) (which is approximately 10% ethanol), while the second
fuel type may be a gasoline alcohol blend with a greater
concentration of alcohol, such as E85 (which is approximately 85%
ethanol). Additionally, the first and second fuels may also differ
in other fuel qualities such as a difference in temperature,
viscosity, octane number, etc. Moreover, fuel characteristics of
one or both fuel tanks may vary frequently, for example, due to day
to day variations in tank refilling.
[0037] Controller 12 is shown in FIG. 1 as a microcomputer,
including microprocessor unit 106, input/output ports 108, an
electronic storage medium for executable programs and calibration
values shown as non-transitory read only memory chip 110 in this
particular example for storing executable instructions, random
access memory 112, keep alive memory 114, and a data bus.
Controller 12 may receive various signals from sensors coupled to
engine 10, in addition to those signals previously discussed,
including measurement of inducted mass air flow (MAF) from mass air
flow sensor 122; engine coolant temperature (ECT) from temperature
sensor 116 coupled to cooling sleeve 118; a profile ignition pickup
signal (PIP) from Hall effect sensor 120 (or other type) coupled to
crankshaft 140; throttle position (TP) from a throttle position
sensor; and absolute manifold pressure signal (MAP) from sensor
124. Engine speed signal, RPM, may be generated by controller 12
from signal PIP. Manifold pressure signal MAP from a manifold
pressure sensor may be used to provide an indication of vacuum, or
pressure, in the intake manifold. Controller 12 may infer an engine
temperature based on an engine coolant temperature. The controller
12 receives signals from the various sensors of FIG. 1 and employs
the various actuators of FIG. 1 to adjust engine operation based on
the received signals and instructions stored on a memory of the
controller. For example, adjusting an amount of intake air flowing
to the cylinder 14 via intake passage 146 may include adjusting a
position of the throttle 162 (e.g., an amount of rotation of the
throttle plate 164) in order to increase or decrease airflow from
the intake passage 144 to the intake passage 146.
[0038] As described above, FIG. 1 shows only one cylinder of a
multi-cylinder engine. As such, each cylinder may similarly include
its own set of intake/exhaust valves, fuel injector(s), spark plug,
etc. It will be appreciated that engine 10 may include any suitable
number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12, or more
cylinders. Further, each of these cylinders can include some or all
of the various components described and depicted by FIG. 1 with
reference to cylinder 14.
[0039] As described above, frictionless motion of engine components
may be enabled by circulating oil through an engine via a
lubrication system. FIG. 2 shows an example embodiment of an engine
oil lubrication system 200 with an oil pump 208 coupled to a
crankshaft, e.g., crankshaft 40 of FIG. 1, and including a first
oil subsystem 216, a second oil subsystem 218, and a third oil
subsystem 220. The lubrication system 200 is enclosed within an
engine 203. In some examples, the lubrication system 200 may a
non-limiting example of the lubrication system 95 of FIG. 1. The
oil subsystems may utilize oil flow to perform a function, such as
lubrication, actuation of an actuator, etc. For example, the first
oil subsystem 216 may be a main oil gallery supplying oil to a
crankshaft and pistons of the engine 203. A first portion of oil
flow, indicated by arrow 205 may be larger than both a second
portion of oil flow, indicated by arrow 207 delivered to the second
oil subsystem 218 and a third portion of oil flow, indicated by
arrow 209, delivered to the third oil subsystem 220. As a result, a
smaller amount of oil with a lower hydraulic pressure is provided
to the second and third oil subsystems 218, 220, than the first oil
subsystem 216. For example, an oil pressure in the main oil gallery
may be 75 psi and oil pressure in the cylinder head oil galleries
(as provided by internal oil passages in the engine 203) may be
10-15 psi during high engine loads. Further, the second oil
subsystem 218 may be a lubrication system, such as a passageway for
delivering oil to oil galleries in a cylinder head of the engine
203 to lubricate moving components, such as the camshafts, cylinder
valves, etc. For example, the first oil subsystem 216 may be an
engine block lubrication system, the second oil subsystem 218 may
be a cylinder head lubrication system, and the third oil subsystem
220 may be a pressure regulation system such as the pressure
regulation system of FIGS. 4-7, delivering oil to the cylinder head
via an external set of oil passages, e.g., the set of external oil
passages 101 of FIG. 1, coupled to a pressure control valve such as
the pressure control valve 93 of FIG. 1. Still further non-limiting
examples of the oil subsystems include camshaft phasers, cylinder
walls, miscellaneous bearings, etc. In some embodiments, there may
be fewer or more oil subsystems.
[0040] Continuing with FIG. 2, the oil pump 208, which may be
actuated by the rotation of the crankshaft, sucks oil from oil
reservoir 204, stored in oil pan 202, through supply channel 206.
Oil is delivered from oil pump 208 with pressure through supply
channel 210 and oil filter 212 to main gallery 214. The pressure
within the main gallery 214 is a function of the force produced by
oil pump 208 and the flow of oil entering each oil subsystem 216,
218, 220 through supply channels 214a, 214b, 214c, respectively.
Oil returns to oil reservoir 204 at atmospheric pressure through
return channel 222. Oil pressure sensor 224 measures main gallery
oil pressure and sends the pressure data to a controller, e.g.,
controller 12 of FIG. 1. Pressure within the main gallery 214 may
be increased or decreased by respectively increasing or decreasing
the force produced by oil pump 208 in response to signals received
from the controller, for example. In other examples, the force
produced by of pump 208 may be passively controlled by engine
operations driving rotation of the crankshaft.
[0041] A hydraulic pressure in a main oil gallery of an engine
lubricant system may affect pressure at other regions of an engine.
For example, a schematic diagram 300 of an engine 302 is shown in
FIG. 3. Engine 302 may be a non-limiting example of engine 10 of
FIG. 1. A set of reference axis 301 are provided, indicating an
x-axis, a y-axis, and a z-axis. The engine 302 includes a cylinder
head, or head 304, arranged above an engine block 306, with respect
to the y-axis and may be adapted with one or more subsystems of a
lubricant system, such as the first, second, and third subsystems
216, 218, 220 of the lubrication system 200 of FIG. 2. The engine
302 has a plurality of oil passages and channels distributed within
the head 304 and the engine block 306 to provide oil to moving
components of the engine 302. An oil sump 308 may be disposed at a
bottom of the engine block 306, coupled to an oil feed line 310
through a sump strainer 312. The oil feed line 310 extends between
the sump strainer 312 (configured to inhibit entrainment of
particulate matter from the oil sump 308 into oil passages of the
engine 302) and an oil pump 314 arranged in the engine block
306.
[0042] The oil pump 314 may be driven by mechanical coupling to a
crankshaft 316 in the engine block 306 and to camshafts 318 in the
head 304 by a loop 320, e.g., a timing belt or chain. Operation of
the oil pump 314 increases oil pressure and forces oil to flow from
the oil sump 308 to the oil pump 314, as indicated by a first set
of arrows 322. The oil continues from the oil pump 312, through an
oil filter 324, as indicated by a second set of arrows 326, and
from the oil filter 324 to a main oil gallery 328, as indicated by
a third set of arrows 330.
[0043] The main oil gallery 328 is positioned in the engine block
306 and distributes oil to moving components within the engine
block 306 such as the crankshaft 316. The main oil gallery 328 is
also coupled to cylinder head oil galleries 332, as indicated by
arrow 334, enabling oil to circulate through the head 304 as
indicated by a fourth set of arrows 336 and lubricating the
camshafts 318. The pressure provided by the oil may enable
operation of hydraulic lash adjusters 338 positioned between the
camshaft 318 and engine valves 340, e.g., intake and exhaust poppet
valves, where the hydraulic lash adjusters 338 may be configured to
maintain zero valve clearance of the engine valves 340. Oil may
return to the oil sump 308 as it is forced out of bearings, e.g.,
bearings of the camshafts 318 and crankshaft 316, and drips
down.
[0044] The engine 302 is further adapted with a pressure regulation
system 350. The pressure regulation system 350 may be a
non-limiting example of the pressure regulation system 220 (e.g.,
the third oil subsystem 220) of FIG. 2. The pressure regulation
system 350 includes an oil feed line 352, extending between the oil
filter 324 and a pressure control valve 354 along an external
surface of the engine 302. The pressure control valve 354 is also
arranged outside of the engine 302. Oil flows from the oil filter
to the pressure control valve 354 through the oil feed line 352, as
indicated by arrows 356, and continues from the pressure control
valve 354 to the cylinder head oil galleries 332 via external oil
passages 358. Each of the external oil passages 358 extends from
the pressure control valve 354, through an external surface of the
engine 302, to one of the cylinder head oil galleries 332. Oil flow
through the external oil passages 358 is indicated by arrows
360.
[0045] Oil pressure in the engine 302 may vary amongst different
regions of the lubrication system 302. Oil in the main oil gallery
328 may be relatively high due to an arrangement of the main oil
gallery 328 directly downstream of the oil filter 324. A relatively
small portion of the oil in the main oil gallery is channeled to
the cylinder head oil galleries 332, as indicated in FIG. 2,
resulting in a lower oil pressure in the cylinder head oil
galleries 332 than in the main oil gallery 328. During some
instances, the oil pressure in the cylinder head oil galleries 332
may be undesirably low. Additional oil pressure may be provided by
the pressure regulation system 350. By delivering oil to the
cylinder head oil galleries 332 directly from the oil filter 324,
the oil pressure in the cylinder head oil galleries 332 may be
enhanced. Oil may flow continuously through the pressure regulation
system 350 when the oil pump 314 is operating, the higher pressure
upstream of the pressure control valve 354 (provided by the oil
filter 324) than downstream of the pressure control valve 354
(e.g., the pressure in the head oil galleries), thereby maintaining
the pressure control valve 354 open. Further details of the
pressure regulation system is described below, with reference to
FIGS. 4-8.
[0046] The pressure regulation system 350 also has a vent line 362,
coupled at one end to the pressure control valve 354 and flowing
oil from the cylinder head oil galleries 332 to the oil filter 324
where oil is returned to the oil sump 308. The flow through the
vent line 362, travelling in an opposite direction from flow
through the oil feed line 352, is indicated by arrows 364. The vent
line 362 may flow oil to alleviate oil pressure when pressure in
the cylinder head oil galleries 332 rises above a preset level of
pressure.
[0047] In other examples, an oil pressure in the engine 302,
downstream of the oil pump 314, may be adjusted by a pressure
relief valve instead of the pressure control valve 354. The
pressure relief valve may open when the oil pump 314 produces a
higher oil pressure than demanded by engine operation to vent
excess pressure and return oil directly to the oil sump 308 via a
bypass, thus maintaining oil pressure below a threshold pressure
level and reducing degradation to oil seals resulting from exposure
to high pressure. However, the pressure relief valve may not
address issues arising from insufficiently high oil pressure in the
head 304, particularly for performance vehicles. Operation of the
camshafts 318 and a valvetrain of the engine 302 may rely on higher
oil pressures in the cylinder head oil galleries 332 than provided
by the pressure relief valve. In some instances, operation of
components in the head 304 may demand higher pressure than provided
by the oil pump 314 through internal oil passage of the engine 302.
Furthermore, the pressure in the head 304 is prone to fluctuations
in response to variations in engine operating conditions which may
affect a temperature of the oil, aeration, slosh, and dilution by
fuel, and lead to changes in pressure. A single size pressure
relief valve may not be able to accommodate the wide range of
pressures and temperatures imposed by engine operations in the
performance vehicle. As a result, oil pressure may differ between
cylinder head oil galleries and contribute to valvetrain
instability.
[0048] The issues described above may be at least partially
addressed by adapting a lubricant system with a pressure regulation
system including external oil passages coupling oil galleries of a
cylinder head to a pressure control valve. The pressure control
valve may provide oil to the head in addition to oil delivered via
internal passages, as shown in FIG. 3, at a consistent oil
pressure, particularly during engine operations under elevated oil
temperatures and aeration. The pressure control valve may also be
positioned external to the engine thereby allowing the pressure
regulation system to be readily adapted to already existing engine
lubricant systems and to both wet and dry sumps. A vent line of the
pressure control valve may alleviate oil pressure if the pressure
control valve becomes degraded and is stuck open. Thus the pressure
regulation system may be retrofit to a variety of engine systems
and may increase engine performance by maintaining a uniform,
regulated cylinder head pressure, particularly in performance
vehicles operating for prolonged periods at high engine oil
temperatures and pressures.
[0049] An example of a pressure regulation system 402, as described
above, is shown in FIGS. 4-7, depicting an engine 404 from a rear
view 400, a left-side view 500, a first zoomed-in view 600 of a
coupling of external oil passages to cylinder head oil galleries,
and a second zoomed-in view 700 of a pressure control valve,
respectively. In some examples, the engine 404 may be the engine 10
of FIG. 1, adapted with a lubricant system such as the lubrication
system 200 of FIG. 2 flowing oil to oil subsystems of the engine
(e.g., the subsystems 216, 218, and 220 of FIG. 2). A set of
reference axis 401 is provided for comparison between views. The
set of reference axes 401 may be similar to the set of reference
axes 301 of FIG. 3. As shown in FIG. 4, the engine 404 includes a
right-side cylinder bank 406 and a left-side cylinder bank 408. A
cylinder head 410, referred to as a head 410 herein, is stacked
above an engine block 412, with respect to the y-axis.
[0050] Oil may be pumped from an oil sump (e.g., the oil sump 308
of FIG. 3) in the engine block 412 to an oil filter 502, the oil
filter 502 shown in FIG. 5, through internal (e.g., inside of the
engine 404) oil passages. In contrast, the pressure regulation
system 402 routes an external oil feed line 504, as shown in FIG.
5, from the oil filter 502 to a pressure control valve 414, as
shown in FIGS. 4 and 7, the external oil feed line 504 extending
along an exterior surface of a left side of the engine block 412,
e.g., below the left-side cylinder bank 408. The oil filter 502 may
receive oil from an oil pump (e.g., the oil pump 208 of FIG. 2 or
314 of FIG. 3), the oil pressurized downstream of the oil pump due
to a flow restriction in an outlet line between the pump and the
oil filter 502. Thus, the oil flowing through the external oil feed
line 504 from the oil filter 502 to the pressure control valve 414
is also pressurized. The external oil feed line 504 may continue
around a rear side 416 of the engine 404, as shown in FIG. 4, and
couple to an inlet 418 of the pressure control valve 414. In one
example, the oil feed line 504 may be formed from a heat and
pressure-tolerant, durable material such as braided stainless
steel. Furthermore, in some examples, the oil feed line 504 may be
encased by a heat-shielding material to reduce exposure of the oil
feed line 504 to heat radiating from an exhaust manifold of the
engine 404.
[0051] The pressure control valve 414 may be positioned at the rear
side 416 of the engine 404, fixedly attached to the engine 404,
above the engine block 412 and between the left-side cylinder bank
408 and the right-side cylinder bank 406, by a mount 430. The mount
430 may be a metal bracket or plate that enables the pressure
control valve 414 to be coupled to an exterior surface of the
engine 404 by a fastening device, such as bolts or clips. The
pressure control valve 414 may have a first outlet 420 and a second
outlet 422 arranged along opposite sides 712 of a body 702 of the
pressure control valve 414, as shown in FIG. 7. The body 702 of the
pressure control valve 414 may be rectangular with inlets and
outlets protruding from the body 702. A first oil passage 424 may
couple the first outlet 420 of the pressure control valve 414 to a
first set of head oil galleries in the head 410 above the left-side
cylinder bank 406, the first oil passage 424 extending along a
first direction, e.g., to the left side of the engine 404 in FIG.
4, away from the pressure control valve 414. A second oil passage
426 may couple the second outlet 422 of the pressure control valve
414 to a second set of head oil galleries in the head 410 above the
right-side cylinder bank 408. The second oil passage 426 may extend
in an opposite direction from the first oil passage 426, e.g., to
the right in FIG. 4, away from the pressure control valve 414. The
first and second sets of head oil galleries within the head 410 may
be similar to the cylinder head oil galleries 318 shown in FIG. 3,
supplying oil to lubricate camshafts and operate hydraulic lash
adjusters, for example. A detailed view of the coupling of the
first oil passage 424 to the first set of head oil galleries
through a wall 602 at the rear side 416 of the engine 404 is shown
in FIG. 6.
[0052] As depicted in FIG. 6, in the engine 404, each set of head
oil galleries may include inlets coupled to two head galleries
corresponding to each cylinder bank of the engine 404. While FIG. 6
shows a zoomed-in view of only the first oil passage 424, the
second oil passage may be similarly coupled to the second set of
head oil galleries in the head 410 above the right-side cylinder
bank 406. The first oil passage 424 may couple to each gallery of
the first set of head oil galleries in the head 410 through a first
gallery inlet 604 and a second gallery inlet 606. Each of the first
and second gallery inlets 604, 606, may be openings through the
wall 602 of the head 410 at the rear side 416 of the engine 404 and
directly coupling the first oil passage 424 to each gallery of the
first set of head oil galleries. A first branch 608 extends between
the first oil passage 424 and the first gallery inlet 604, forming
a T-junction in the first oil passage 424 that fluidly couples the
first oil passage 424 to the first gallery inlet 604. A second
branch 610 is parallel with the first branch 608 and continues from
an end 612 of the first oil passage 424 to couple the first oil
passage to the second gallery inlet 606. The first and second
branches 608 and 610 may include fittings adapted to sealingly
engage with the first oil passage 424 via, for example, threaded
interfacing regions, so that oil does not leak through the fittings
even when the oil is under pressure.
[0053] The oil delivered to the first set of head oil galleries via
the first oil passage 424, flowing in a direction indicated by
arrows 612, may supplement oil provided by the internal oil
passages of the head 410, thereby increasing an oil pressure in the
first set of head oil galleries of the head 410. The higher
pressure may enable smoother and more stable camshaft operation as
well as intake and exhaust valve actuation. Additionally,
implementation of the pressure control valve 414, as shown in FIGS.
4 and 7, may regulate the oil pressure in the first (and second)
set of head oil galleries thereby maintaining a more uniform
pressure in the sets of head oil galleries than achieved by
adapting the internal oil passages with a pressure relief
valve.
[0054] The pressure control valve 414 is depicted in a second
zoomed-in view 700 in FIG. 7. As described above, the external oil
feed line 504 may couple the inlet 418 of the pressure control
valve 414 to the oil filter 502 arranged on the left side of the
engine block 412. The external oil feed line 504 may extend along
the left side of the engine block 412 and continue along the rear
side 416 of the engine 404 to connect to the pressure control valve
414, delivering pressurized oil from the oil filter 502. The
pressurized oil enters the pressure control valve 414 through the
inlet 418 and may flow into the body 702 of the pressure control
valve 414. The body 702 of the pressure control valve 414 may
include a valve configured to adjust an oil pressure communicated
to the sets of head oil galleries through the first outlet 420 and
the second outlet 422 of the pressure control valve 414.
[0055] In one example, the valve in the body 702 of the pressure
control valve 414 may be a reducing valve, configured to be
normally closed. The reducing valve may include an adjustable
opening that controls an amount of oil flowing through the valve to
achieve a target pressure in the sets of head oil galleries
downstream of the pressure control valve 414 and maintain the
pressure of the oil emerging from the pressure control valve 414 at
the target pressure. The amount of oil added to the sets of head
oil galleries may be metered to increase the hydraulic pressure in
the sets of head oil galleries (provided by the internal oil
passages of the engine 404) to the target pressure. For example, a
main oil gallery of the engine 404, such as the main oil gallery
328 of FIG. 3, may have a hydraulic pressure of 75 psi (517 kPa) as
generated downstream of the oil pump and the target pressure of the
pressure control valve 414 may be 45 psi (310 kPa).
[0056] To control oil flow and maintain a uniform pressure in the
first and second oil passages 424, 426, as shown in FIG. 4, the
reducing valve of the pressure control valve 414 may have a
spindle, a diaphragm, and a spring coupled to the spindle and
exerting pressure on the diaphragm. In one example, the diaphragm
may be formed from a polymer such as Viton.TM.. The spindle may be
fixedly attached to a knob 704, the knob 704 shown in FIG. 7, and
rotation of the knob 704 drives rotation of the spindle. The knob
704 and the spindle may be rotated in either of two directions
(e.g., clockwise and counterclockwise) to adjust the pressure
exerted by the spring on the diaphragm and thereby adjusting a
hydraulic pressure of the oil emerging from the pressure control
valve 414. For example turning the knob 704 clockwise may increase
the pressure while turning the knob 704 counterclockwise may
decrease the pressure, or vice versa. Thus the target pressure may
be set by rotating the knob 704 to achieve a desired pressure
reduction relative to the main oil gallery pressure.
[0057] In other examples, the reducing valve may include a
mechanism other than the spindle, diaphragm, and spring. For
example, the pressure control valve 414 may be adapted with a solid
piston to reduce the hydraulic pressure from the oil filter 502.
Other types of reducing valves may be similarly used in the
pressure control valve 414 without departing from the scope of the
present disclosure.
[0058] The pressure control valve 414 may further include a vent
line 706 coupled to the body 702 of the pressure control valve 414
and arranged substantially parallel with the external oil feed line
504 along the left side of the engine 404, as shown in FIG. 5. As
shown in FIG. 7, the vent line 706 may feed into the body 702 of
the pressure control valve 414 at a top 708 of the body 702,
adjacent to the knob 704 and opposite of the inlet 418, the inlet
418 disposed in a bottom 710 of the body 702 of the pressure
control valve 414. The first outlet 420 and the second outlet 422
may be arranged between the inlet 418 and a coupling region of the
vent line 706 with the body 702 of the pressure control valve 414,
at the top 708 of the body 702, along opposite sides 712 of the
body 702 of the pressure control valve 414. Thus each of the first
oil passage 424, the second oil passage 426, the oil feed line 504,
and the vent line 706 may each attach to a different region of the
body 702 of the pressure control valve 414. The passages and lines
may be coupled to the body 702 by various types of fittings
suitable for high pressure, high temperature fluid
applications.
[0059] Oil flow into and out of the pressure control valve 414 is
indicated by arrows 714 in FIG. 7. Oil enters the pressure control
valve 414 through the inlet 418 and flows out through the first
outlet 420 and the second outlet 422 with a reduced pressure
relative to the pressure at the inlet 418. Flow through the vent
line 706 may be blocked in the pressure control valve 414 until the
diaphragm of the pressure control valve 414 ruptures. When
hydraulic pressure in the body 702 of the pressure control valve
414 exceeds the threshold pressure set by adjusting the knob 704
the high pressure is communicated through the first oil passage 424
and the second oil passage 426 to the pressure control valve 414.
If the pressure control valve 414 is degraded, all the oil in the
body 702 flows through the vent line 706 to retain the oil within a
lubricant system of the engine 404 and to mitigate ignition of
leaked oil if the oil leaks into the engine bay. Leakage of oil in
the engine bay may occur if the vent line 706 is not
implemented.
[0060] For example, oil may flow through the vent line 706 when the
pressure control valve 414 is degraded and unable to control the
pressure of oil flowing to the sets of head oil galleries through
the first oil passage 424 and the second oil passage 426. In some
instances, the diaphragm of the reducing valve in the pressure
control valve 414 may no longer provide a seal to control oil
pressure and the pressure control valve 414 may be stuck in an open
position without pressure regulation, allowing the high pressure in
the oil feed line 504 to be communicated to the set of head oil
galleries when the pressure control valve 414 is degraded. The high
oil pressure in the oil feed line 504 may be higher than a pressure
tolerance of components in the head 410 and may lead to degradation
of the components and cause leakage. To circumvent exposure of the
head components to high pressures and oil leakage from the head
410, the pressure control valve 414 may be configured to allow oil
to flow through the vent line 706 from the pressure control valve
414 to the oil filter 502 (as shown in FIG. 5) to alleviate oil
pressure rising higher than the threshold pressure in the pressure
control valve 414. Oil may continue flowing through the vent line
706 until the pressure control valve 414 is repaired or
replaced.
[0061] Oil flowing through the vent line 706 to alleviate oil
pressure in the head 410 may be returned to the oil filter 502 (as
shown in FIG. 5) and to the oil sump, travelling through the vent
line 706 in an opposite direction relative to flow through the oil
feed line 504 as indicated by arrows 714 shown in FIG. 7. Thus at
least a portion of oil flowing through the oil feed line 504 from
the oil filter 502 to the pressure control valve 414 may circulate
between the pressure control valve 414 and oil filter 502 via the
oil feed line 504 and the vent line 706 when the pressure in the
pressure control valve 414 is higher than the threshold pressure or
when the pressure control valve is degraded.
[0062] As shown in FIGS. 4 and 7, the oil feed line 504 and the
vent line 706 may both extend away from the pressure control valve
414 to the left and wrap around the left side of the engine 404 to
continue to the oil filter 502. The oil feed line 504 and the vent
line 706 may be secured to one another and to exterior surfaces of
the engine 404 by one or more clamps 428, as shown in FIGS. 4-6.
The clamps 428 may be oval or shaped like a FIG. 8, configured to
circumferentially surround both the oil feed line 504 and the vent
line 706 and be fixedly attached to the engine 404 by a fastener.
The clamps 428 may be formed of a strip of metal at least partially
covered by a more flexible, heat-resistant material such as rubber.
The oil feed line 504 and the vent line 706 may be in contact with
one another at least at each of the clamps 428. Variations in a
number of clamps 428 used may differ from the amounts shown in
FIGS. 4-6.
[0063] By adapting a lubricant system of an engine with a pressure
regulation system such as the pressure regulation system 402 of
FIGS. 4-7, pressure amongst oil galleries in a head of an engine
may be maintained more uniform. Each oil gallery in the head is
similarly coupled to a pressure control valve, e.g., the pressure
control valve 414 of FIGS. 4 and 7, via oil passages external to
the engine thereby providing a uniform hydraulic pressure across
all oil galleries in the head. The pressure control valve may
reduce an oil pressure communicated from a main oil gallery of the
engine prior to distributing the oil to the oil galleries in the
head. The oil pressure provided by pressure regulation system may
be delivered exclusively to the head, adding to oil pressure
supplied by the internal oil passages of the engine.
[0064] Implementation of the pressure regulation system 402 of
FIGS. 4-7 rather than, for example, a pressure relief valve system,
may provide other benefits in addition to pressure consistency
across the oil galleries in the head. The pressure regulation
system 402 may enable control of oil gallery pressure over a wider
range of flow rates than the pressure relief valve. For example, a
conventional pressure relief valve system may not be adapted to
control pressure at flow rates lower than 2 gallons per minute
(gpm) when a pressure of the main oil gallery is high, such as 75
psi. The pressure control valve of the pressure regulation system
402, however, may maintain control over oil gallery pressure at
flow rates as low as 0.5 gpm at the same high main oil gallery
pressure, thereby reducing a likelihood of aeration. At lower main
oil gallery pressure, such as 60 psi, the pressure control valve
may be able to regulate the oil gallery pressure in the head up to
40 psi while the pressure relief valve system may only reach 35
psi. Furthermore, the pressure control valve may be less likely to
overshoot a target or threshold pressure that is lower than the
main oil gallery pressure when the oil is cold.
[0065] A vent line of the pressure regulation system 402 enhances
the ability of the pressure regulation system 402 to regulate
pressure in the oil galleries of the head and mitigate pressure
rise in the oil galleries of the head when the pressure control
valve become degraded and stuck open by providing a route for oil
pressure to be returned to an oil filter. In addition, the pressure
regulation system 402 includes components configured to be arranged
external to, e.g., outside of, the engine and may thus be readily
retrofit to already existing engine systems.
[0066] Example operations of a pressure regulation system for an
engine are shown in map 800 as shown in FIG. 8. The engine may have
internal oil passages delivering oil from an oil reservoir, such as
an oil sump, through an oil filter and to a main oil gallery in the
engine block as well as oil galleries in a head of the engine. The
pressure regulation system may be the pressure regulation system
402 of FIGS. 4-7, having an external oil feed line flowing oil from
the oil filter to a pressure control valve. External oil passages
may couple the pressure control valve to the oil galleries in a
head of the engine, delivering oil to the oil galleries in addition
to oil provided by the internal oil passages. The pressure control
valve may be adapted with a vent line to flow oil from the pressure
control valve to the oil filter and may be set to maintain a
threshold pressure in the oil galleries in the head of the engine.
Map 800 shows time plotted along the x-axis and increasing to the
right. Engine speed is depicted at plot 802 and an opening of the
pressure control valve, adjustable between a fully open (e.g., a
maximum opening of the pressure control valve) and a closed
position is shown at plot 804. A pressure in the oil galleries in
the head is shown at plot 806, increasing along the y-axis, a
pressure in an internal oil passage extending between the main oil
gallery and the head oil galleries to flow oil from the main oil
gallery and the head oil galleries is shown at plot 808, increasing
along the y-axis, and flow rate of oil through the vent line is
shown at plot 810, also increasing along the y-axis.
[0067] At t0, the engine is operating (plot 802) and the pressure
control valve is open (plot 804), at a position between fully open
and closed as set by, for example, an operator prior to engine
operation. The pressure control valve maintains the pressure in the
head oil galleries at a threshold pressure 812, as shown at plot
806. The oil pressure in the internal oil passage (plot 808)
flowing oil from the main oil gallery to the head oil galleries
fluctuates according to engine speed due to coupling of an oil pump
to a crankshaft of the engine. Oil does not flow through the vent
line (plot 810). At t1, the pressure in the internal oil passage
decreases in response to a decrease in engine speed. For example,
the engine may enter an idling mode at a high engine temperature,
the heated oil having a low viscosity that leads to a decrease in
oil pressure. The pressure control valve remains open, maintaining
the head oil galleries at the threshold pressure 812, and oil does
not flow through the vent line. Depending on engine speed falling
below a threshold speed, such as 3000 rpm, the main oil gallery
pressure and pressure in the external oil feed line falls below a
set point of the pressure regulation system, such as 40 psi. The
pressure in the head oil galleries also drop due to lack of oil
delivery from the pressure regulation system.
[0068] At t2, the engine speed increases so that the pressure in
the internal oil passage rises. At The pressure control valve
remains open and the pressure in the oil galleries is maintained at
the threshold pressure 812. Oil does not flow through the vent
line.
[0069] Engine operation continues between t2 and t3 with the engine
speed higher than at t2, the pressure in the internal oil passage
higher than at t2, and pressure in the head oil galleries regulated
by the open pressure control valve. At t3 the pressure control
valve becomes degraded and unable to regulate pressure. For
example, a diagram of the pressure control valve may be ruptured or
lose a sealing engagement within the pressure control valve due to
prolonged exposure to heat and pressure. The degraded pressure
control valve is no longer able to control pressure delivered to
the head oil galleries through the external oil passages and a
higher pressure in the oil feed line may be transmitted directly to
the head oil galleries, causing pressure in the head oil galleries
to rise at t3. In response to the increasing pressure in the head
oil galleries, oil may flow through the vent line.
[0070] Rising pressure in the head oil galleries is offset by the
flow through the vent line, alleviating the pressure increase in
the head oil galleries and returning the pressure to the threshold
pressure 812 at t4 by circulating oil from the head oil galleries
to the oil reservoir. Oil may continue flowing through the vent
line until mitigating actions are performed, such as stopping the
engine and replacing or repairing the pressure control valve.
[0071] In this way a hydraulic pressure may be maintained uniform
across cylinder head oil galleries of an engine. The engine may be
adapted with a pressure regulation system including external
passages delivering a hydraulic fluid, such as oil, from an oil
reservoir to the cylinder head oil galleries. A pressure control
valve is coupled to each of the external passages, reducing a
hydraulic pressure of the oil delivered to the cylinder head oil
galleries, downstream of the pressure control valve, relative to
the hydraulic pressure upstream of the pressure control valve. The
pressure control valve may have a vent line configured to vent
excess hydraulic pressure above a preset pressure threshold of the
pressure control valve by flowing oil from the cylinder head oil
galleries to the oil reservoir. The vent line precludes use of a
bypass line which may otherwise incur parasitic losses and enables
the pressure regulation system to continue regulating pressure in
the cylinder head oil galleries even if the pressure control valve
becomes degraded. Components of the pressure regulation system are
arranged external to the engine, allowing the system to be
configured as a retrofit kit adaptable to a variety of engine
types.
[0072] The technical effect of adapting an engine with the pressure
regulation system of FIGS. 4-7 is that a valvetrain of the engine
is maintained more stable and parasitic losses are reduced.
[0073] FIGS. 3-7 show example configurations with relative
positioning of the various components. If shown directly contacting
each other, or directly coupled, then such elements may be referred
to as directly contacting or directly coupled, respectively, at
least in one example. Similarly, elements shown contiguous or
adjacent to one another may be contiguous or adjacent to each
other, respectively, at least in one example. As an example,
components laying in face-sharing contact with each other may be
referred to as in face-sharing contact. As another example,
elements positioned apart from each other with only a space
there-between and no other components may be referred to as such,
in at least one example. As yet another example, elements shown
above/below one another, at opposite sides to one another, or to
the left/right of one another may be referred to as such, relative
to one another. Further, as shown in the figures, a topmost element
or point of element may be referred to as a "top" of the component
and a bottommost element or point of the element may be referred to
as a "bottom" of the component, in at least one example. As used
herein, top/bottom, upper/lower, above/below, may be relative to a
vertical axis of the figures and used to describe positioning of
elements of the figures relative to one another. As such, elements
shown above other elements are positioned vertically above the
other elements, in one example. As yet another example, shapes of
the elements depicted within the figures may be referred to as
having those shapes (e.g., such as being circular, straight,
planar, curved, rounded, chamfered, angled, or the like). Further,
elements shown intersecting one another may be referred to as
intersecting elements or intersecting one another, in at least one
example. Further still, an element shown within another element or
shown outside of another element may be referred as such, in one
example.
[0074] In one embodiment, a system includes delivery lines,
arranged external to an engine, the delivery lines coupling an oil
reservoir of the engine to a plurality of cylinder head oil
galleries along an external surface of the engine, the oil
reservoir also coupled to the plurality of cylinder head oil
galleries via oil passages internal to the engine, a pressure
control valve, arranged external to the engine, for controlling an
amount of hydraulic fluid delivered through the delivery lines,
each of the delivery lines coupled to the pressure control valve,
and an external vent line configured to couple the pressure control
valve to the oil reservoir when the pressure control valve is
degraded. In a first example of the system, the delivery lines
include an oil feed line flowing oil from the oil reservoir to the
pressure control valve with a first amount of hydraulic pressure. A
second example of the system optionally includes the first example,
and further includes, wherein the delivery lines include external
passages flowing oil from the pressure control valve to the each of
the plurality of cylinder head oil galleries with a second amount
of hydraulic pressure, the second amount lower than the first
amount of hydraulic pressure. A third example of the system
optionally includes one or more of the first and second examples,
and further includes, wherein the external passages each include an
end configured to couple to a respective cylinder head oil gallery
through a respective inlet opening in a wall of the engine. A
fourth example of the system optionally includes one or more of the
first through third examples, and further includes, wherein the
pressure control valve has an inlet positioned at a bottom side of
the pressure control valve, outlets positioned at oppositely
arranged sides of the pressure control valve, and a mechanism for
adjusting oil flow through the pressure control valve positioned at
a top side of the pressure control valve. A fifth example of the
system optionally includes one or more of the first through fourth
examples, and further includes, wherein the vent line is coupled to
the pressure control valve at the top side of the pressure control,
adjacent to the mechanism for adjusting oil flow through the
pressure control device. A sixth example of the system optionally
includes one or more of the first through fifth examples, and
further includes, wherein the pressure control valve is mounted to
the external surface of the engine at a side opposite of a location
of an oil filter of the engine. A seventh example of the system
optionally includes one or more of the first through sixth
examples, and optionally includes, wherein the oil flows from the
pressure control valve to the oil reservoir through the vent line.
An eighth example of the system optionally includes one or more of
the first through seventh examples, and further includes, wherein
the oil delivered to the plurality of cylinder head oil galleries
provides hydraulic pressure in addition to hydraulic pressure
provided by the oil passage internal to the engine block.
[0075] In another embodiment, a system includes an oil sump
arranged below an engine block, a cylinder head arranged above the
engine block, an internal passage, internal to the engine block and
coupling the oil sump to cylinder head oil galleries of the engine,
one or more external passages, external to both the engine block
and the cylinder head, also coupling the oil sump to the cylinder
head oil gallery, the one or more external passages separate from
the internal passage, a pressure control valve coupled to each of
the one or more external passages, the pressure control valve
having a vent line configured to flow oil to the oil sump when a
pressure in the cylinder head oil gallery rises above a threshold
pressure. In a first example of the system, the one or more
external passages flow oil to the cylinder head oil galleries
simultaneous with oil flowing to the cylinder head oil galleries
from the internal passage. A second example of the system
optionally includes the first example, and further includes,
wherein the one or more external passages includes a feed line
coupled at a first end to an oil filter, the oil filter arranged
between the feed line and the oil sump, and coupled at a second end
to the pressure control valve and wherein the feed line is
configured to deliver oil from the oil sump to the pressure control
valve via the oil filter. A third example of the system optionally
includes one or more of the first and second examples, and further
includes, wherein the one or more external passages includes a
first passage delivering oil from the pressure control valve to a
first set of galleries of the cylinder head oil galleries and a
second passage delivering oil from the pressure control valve to a
second set of galleries of the cylinder head oil galleries. A
fourth example of the system optionally includes one or more of the
first through third examples, and further includes, wherein a
hydraulic pressure in the feed line is higher than a hydraulic
pressure in each of the first and second passages. A fifth example
of the system optionally includes one or more of the first through
fourth examples, and further includes, wherein the pressure control
valve is configured to maintain a uniform hydraulic pressure to the
first and second passages by adjusting an amount of oil flowing
through the pressure control valve to the first and second
passages. A sixth example of the system optionally includes one or
more of the first through fifth examples, and further includes,
wherein the pressure threshold is set at the pressure control valve
and wherein when the pressure control valve is degraded and stuck
open, oil flows from the pressure control valve to the oil sump
through the vent line.
[0076] In yet another embodiment, a kit includes a pressure control
valve, a feed line coupled to an inlet of the pressure control
valve, passages coupled to outlets of the pressure control valve at
first ends of each of the passages and configured to couple to oil
galleries in a cylinder head of the engine at second ends of each
of the passages, a vent line connected to the pressure control
valve and configured to vent oil from the oil galleries in the
cylinder head when a hydraulic pressure in the oil galleries
increases above a threshold pressure. In a first example of the
kit, the pressure control valve, the feed line, the passages, and
the vent line are all configured to be positioned external to the
engine. A second example of the kit optionally includes the first
example, and further includes, wherein the kit is configured to be
coupled to a wet oil sump of the engine. A third example of the kit
optionally includes one or more of the first and second examples,
and further includes, wherein the kit is configured to be coupled
to a dry oil sump of the engine.
[0077] In another representation, a pressure regulation system for
an engine includes a pressure control valve having a vent line and
arranged externally at a rear side of the engine, a set of external
passages branching from the pressure control valve and coupling
each of an oil reservoir of the engine and cylinder head oil
galleries to the pressure control valve and wherein a uniform
pressure is maintained at each of the cylinder head oil galleries
by the pressure control valve.
[0078] It will be appreciated that the configurations and routines
disclosed herein are exemplary in nature, and that these specific
embodiments are not to be considered in a limiting sense, because
numerous variations are possible. For example, the above technology
can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine
types. The subject matter of the present disclosure includes all
novel and non-obvious combinations and sub-combinations of the
various systems and configurations, and other features, functions,
and/or properties disclosed herein.
[0079] The following claims particularly point out certain
combinations and sub-combinations regarded as novel and
non-obvious. These claims may refer to "an" element or "a first"
element or the equivalent thereof. Such claims should be understood
to include incorporation of one or more such elements, neither
requiring nor excluding two or more such elements. Other
combinations and sub-combinations of the disclosed features,
functions, elements, and/or properties may be claimed through
amendment of the present claims or through presentation of new
claims in this or a related application. Such claims, whether
broader, narrower, equal, or different in scope to the original
claims, also are regarded as included within the subject matter of
the present disclosure.
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