U.S. patent number RE35,303 [Application Number 08/317,042] was granted by the patent office on 1996-07-30 for apparatus for adjustably controlling valve movement and fuel injection.
This patent grant is currently assigned to Caterpillar Inc.. Invention is credited to Charles R. Miller, Tsu P. Shyu, J. Roger Weber.
United States Patent |
RE35,303 |
Miller , et al. |
July 30, 1996 |
Apparatus for adjustably controlling valve movement and fuel
injection
Abstract
An apparatus adjustably controls intake and exhaust valve
movement and fuel injection of an engine. Valve movement and
injection is adjustably controlled in response to electrical
signals delivered to a piezoelectric motor which in turn delivers
hydraulic signals through a single spool valve.
Inventors: |
Miller; Charles R. (Metamora,
IL), Shyu; Tsu P. (Dunlap, IL), Weber; J. Roger
(Chillicothe, IL) |
Assignee: |
Caterpillar Inc. (Peoria,
IL)
|
Family
ID: |
25517932 |
Appl.
No.: |
08/317,042 |
Filed: |
October 3, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
971103 |
Nov 4, 1992 |
05237968 |
Aug 24, 1993 |
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Current U.S.
Class: |
123/90.11;
123/90.12; 123/498; 123/508 |
Current CPC
Class: |
F01L
9/20 (20210101); F02M 57/04 (20130101); F02M
57/025 (20130101); F01L 1/26 (20130101); F01L
9/10 (20210101); F02F 1/4214 (20130101); F02F
2001/247 (20130101); F02B 3/06 (20130101) |
Current International
Class: |
F01L
1/26 (20060101); F02M 57/00 (20060101); F02M
57/02 (20060101); F02M 57/04 (20060101); F01L
9/00 (20060101); F01L 9/02 (20060101); F02F
1/24 (20060101); F02B 3/00 (20060101); F02B
3/06 (20060101); F02F 1/42 (20060101); F01L
009/02 (); F02M 037/04 () |
Field of
Search: |
;123/90.11,90.12,90.13,90.14,90.15,507,508,498 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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204962 |
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Nov 1983 |
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JP |
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2107393 |
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Apr 1983 |
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GB |
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2405 |
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Apr 1986 |
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WO |
|
Primary Examiner: Lo; Weilun
Attorney, Agent or Firm: Keen; Joseph W.
Claims
We claim:
1. Apparatus for adjustably controlling valve movement and fuel
injection of an engine having at least one fuel injection system,
one exhaust valve system, one intake valve system, a microprocessor
controller for receiving input signals and delivering engine
controlling electrical signals, and a liquid pressure system,
comprising:
a single .[.piezoelectric motor.]. .Iadd.electric motor means
.Iaddend.connectable to the microprocessor controller and the
liquid pressure system and being adapted to receive engine
controlling electrical signals from the microprocessor and
controllably delivering pressurized liquid signals to the liquid
pressure system in response to said received signal; and
a spool valve having a single spool, said .Iadd.spool
.Iaddend.valve having a plurality of inlets and outlets and being
connectable to the liquid pressure system for receiving .Iadd.said
.Iaddend.pressurized liquid signals therefrom and controllably
moving the single spool of the spool valve .Iadd., .Iaddend.and
.Iadd.said spool valve .Iaddend.delivering .Iadd.exhaust and intake
.Iaddend.valve .Iadd.system .Iaddend.and .Iadd.fuel
.Iaddend.injection .Iadd.system .Iaddend.controlling signals to the
.Iadd.exhaust and intake .Iaddend.valve systems and .[.injector.].
.Iadd.the fuel injection .Iaddend.system.Iadd., .Iaddend.and
.Iadd.said spool valve .Iaddend.controlling both .[.valve.].
movement .Iadd.of the exhaust and intake valve systems .Iaddend.and
fuel injection .Iadd.system .Iaddend.responsive to engine
controlling electrical signals received by said .[.piezoelectric
motor.]. .Iadd.electric motor means.Iaddend..
2. An apparatus, as set forth in claim 1, wherein the
.[.piezoelectric motor.]. .Iadd.electric motor means
.Iaddend.includes an amplifier piston adapted to increase, to a
preselected magnitude, the pressure of the pressurized liquid
signals delivered from the .[.piezoelectric.]. .Iadd.electric
.Iaddend.motor .Iadd.means.Iaddend..
3. An apparatus, as set forth in claim 2, wherein the amplifier
piston increases the liquid pressure signals to a ratio magnitude
in the range of about 5:1 to about 9:1.
4. An apparatus, as set forth in claim 3, wherein the ratio
magnitude is about 7:1.
5. An apparatus, as set forth in claim 1, wherein the spool of the
spool valve is spring biased to a first position and movable in
response to receiving the pressurized liquid signal.
6. An apparatus, as set forth in claim 5, including a Bellville
spring and wherein the spool of the spool valve is biased by said
Bellville spring.
7. An apparatus, as set forth in claim 1, wherein the liquid of the
liquid pressure system and liquid controlling .[.systems.].
.Iadd.signals .Iaddend.is diesel fuel.
8. An apparatus, as set forth in claim 1, wherein the injection
system and the valve systems are powered by pressurized liquid from
the spool valve.
9. An apparatus, as set forth in claim 1, wherein the engine has a
plurality of cylinders each having at least one fuel injection
system, at least one exhaust valve system .[.and.]..Iadd.,
.Iaddend.at least one intake valve system .[.connected to.]..Iadd.,
.Iaddend.a respective .[.piezoelectric motor.]. .Iadd.electric
motor means .Iaddend.and a respective spool valve, each of said
.[.piezoelectric motors.]. .Iadd.electric motor means .Iaddend.and
spool valves being connectable to a common liquid pressure
system.
10. An apparatus, as set forth in claim 9, wherein the plurality of
.[.piezoelectric motors.]. .Iadd.electric motor means .Iaddend.are
connected to and receive controlling electrical signals from a
single microprocessor.
11. An apparatus, as set forth in claim 1, wherein the liquid
pressure system is a rail system.
12. An apparatus, as set forth in claim 11, wherein the liquid
pressure rail system has a high pressure rail and a low pressure
rail.
13. an apparatus, as set forth in claim 12, wherein the high
pressure rail is maintained at a pressure in the range of about
2000 to about 4000 psia/psig.
14. An apparatus, as set forth in claim 13, wherein the high
pressure rail is maintained at a pressure of about 3000
psia/psig.
15. An apparatus, as set forth in claim 12, wherein the low
pressure rail is maintained at a pressure in the range of about 100
to about 300 psia/psig.
16. An apparatus, as set forth in claim 15, wherein the low
pressure rail is maintained at a pressure of about 200 psia/psig.
Description
TECHNICAL FIELD
This invention relates generally to an apparatus for adjustably
controlling valve movement and fuel injection of an engine. More
specifically, this invention relates to means for adjustably
controlling valve movement and fuel injection of an engine in
response to electrical signals.
BACKGROUND ART
A conventional internal combustion engine uses either a cam and
push rod system or a direct acting overhead cam operating on a
rocker-arm to actuate the engine poppet valves. The camshaft
typically runs the length of the engine and is driven by a gear
train off of the crankshaft. The engine valve timing events are
fixed with respect to the crankshaft position and the lift rate of
the valve is proportional to engine speed. These restrictions upon
the engine valves induce compromises in engine performance
regarding fuel consumption, emissions, torque, and idle quality. To
minimize these compromises, numerous methods have been introduced
to vary the phasing of the intake and exhaust valve cams relative
to crankshaft position. The variable valve actuation mechanisms are
inherently costly and complex.
The diesel engine camshaft with direct fuel injection typically has
a cam to drive the injector plunger. The fuel injector cam
.[.lob.]. .Iadd.lobe .Iaddend.is especially prone to durability
problems with high pressure fuel injection systems. In another type
system, as taught in U.S Pat. No. 4,009,695 which issued on Mar. 1,
1977 to Louis A. Ule, the valves are operated by two separate valve
assemblies which are moved in response to a mechanical apparatus
which is controlled by engine speed.
The subject invention combines direct high pressure fuel injection
with intake and exhaust valve actuation in a single hydraulically
powered device. The subject invention replaces the camshaft and
conventional valve train components thereby reducing the engine
part count and maintenance. The subject invention has the ability
to electronically adjust valve and fuel injection timing which
provides a freedom to optimize engine performance at any engine
load or speed. The subject invention allows a modular approach to
engine design which would be difficult to accomplish with a
mechanical valve train system.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, there is provided an
apparatus for adjustably controlling valve movement and fuel
injection of an engine. The engine has at least one fuel injection
system, at least one exhaust valve system, at least one intake
valve system, a microprocessor controller for receiving input
signals and delivering engine controlling electrical signals, and a
liquid pressure system.
A single piezoelectric motor is connectable to the microprocessor
controller and the liquid pressure system. The piezoelectric motor
is adapted to receive engine controlling electrical signals from
the microprocessor and controllably deliver pressurized liquid
signals to the liquid pressure system in response to the received
signals.
A spool valve has a single spool and a plurality of inlets and
outlets. The spool valve is connectable to the liquid pressure
system for receiving pressurized liquid signals therefrom and
controllably moving the single spool of the spool valve. The spool
valve delivers liquid valve and injection controlling signals to
the valve system and injector system and controls both valve
movement and fuel injection responsive to engine controlling
electrical signals received by the piezoelectric motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of the apparatus of this
invention;
FIG. 2 is a diagrammatic view of another embodiment of the
apparatus of this invention;
FIG. 3 is a diagrammatic view of apparatus associated with the
apparatus of this invention; and
FIG. 4 is a graph of crankangles vs. lift.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIGS. 1 and 2, the apparatus 2 of this invention is
used for adjustably controlling movement of the intake valves 4
.[.,4'.]. .Iadd.or Z,Z'.Iaddend., the exhaust valves 6 .[.,6'.].
.Iadd.or Y,Y' .Iaddend.and controlling fuel injection of an engine
(not shown). FIG. 1 shows one intake valve 4, one exhaust valve 6
and one fuel injection system 8. FIG. 2 shows an embodiment wherein
each cylinder 10 of the engine is associated with two intake valves
.[.4,4'.]. .Iadd.Z,Z'.Iaddend., two exhaust valves .[.6,6'.].
.Iadd.or Y,Y' .Iaddend.and one fuel injection system 8.
A microprocessor controller 12, as is well known in the art, is
provided for receiving input signals and delivering engine
controlling electrical signals via line 14. The apparatus 2 has a
liquid pressure system 16 .[.as further shown in FIG. 3.]..
As better seen in FIG. 1, a single piezoelectric motor 18 is
connectable to the microprocessor controller 12 and the liquid
pressure system 16. The piezoelectric motor 18 is adapted to
receive controlling electrical signals via line 13 from the
microprocessor 12 and controllably deliver pressurized liquid
signals via line 20 to the liquid pressure system 16 in response to
said received signals.
The liquid pressure system 16 has a spool valve 22 which has a
single spool 24. The valve 22 has a plurality of inlets 26 and
outlets 28 and is connectable to the liquid pressure system 16 for
receiving pressurized liquid signals therefrom and controllably
moving the single spool 24 of the spool valve 22 which in turn
delivers valve and injection controlling signals to the valve
systems, which include the intake valve 4 and exhaust valve 6 and
to the fuel injection system 8. Thereby, the apparatus of this
invention controls both valve movement and fuel injection
responsive to engine controlling electrical signals received by the
piezoelectric motor 18.
The piezoelectric motor i8 is well known in the art and includes an
amplifier piston 30 which is adapted to increase, to a preselected
magnitude, the pressure of the pressurized liquid signals delivered
from the piezoelectric motor 18. Preferably, the amplifier piston
increases the liquid pressure signals to a ratio magnitude in the
range of about 5:1 to about 9:1, more preferably to a ratio of
about 7:1. Ratio magnitudes greater than about 9:1 are undesirable
because the large diameter required of the piezoelectric motor
.Iadd., .Iaddend.and ratio magnitudes less than about 5:1 are
undesirable because of the long length required of the
piezoelectric motor. As is known in the art, component sizes are
limiting factors because of crowded engine compartment
conditions.
The single spool 24 of the spool valve 22 is spring biased to a
first position and is movable in response to receiving the
pressurized liquid signals from the piezoelectric motor 18.
Preferably, the spool 24 of the spool valve 22 is biased by a
Bellville spring, as is well known in the art.
In order to provide a simple, yet effective system, it is preferred
that the liquid of the liquid pressure system 16 and the liquid
controlling signals is diesel fuel. Hence, the injection system 8
and the valves 4,6 are powered and controllably moved during
operation of the engine by hydraulics with the pressurized liquid
for controlling passing from the spool valve 22.
As is known in the art and shown schematically in FIG. 2, an engine
generally has a plurality of cylinders 10 .[.,10'.]. each having at
least one fuel injection system .[.(X).]. .Iadd.8.Iaddend., at
least one exhaust valve system (Y), and at least one intake valve
system (z). As is further known in the art, the engines generally
have a multiplicity of cylinders 10 and associated apparatus as
described above, however, for simplicity, only .[.two cylinders.].
.Iadd.one cylinder .Iaddend.10 .[.,10'.]. and associated apparatus
are shown with primed numbers representing similar or identical
apparatus.
The engine having the plurality of cylinders 10 and associated
apparatus are each connected to a respective separate piezoelectric
motor 18 and a respective spool valve 22 with each of said
piezoelectric motors and spool valves being connectable to the
common liquid pressure system 16. The plurality of piezoelectric
motors are connected to and receive engine controlling electrical
signals from a single microprocessor.
In the preferred embodiment, as better seen in FIG. 1 .Iadd.and 3
in conjunction.Iaddend., the .Iadd.common .Iaddend.liquid pressure
system 16 .[.is.]. .Iadd.includes .Iaddend.a rail system, as is
known in the art. One rail 32 is of high pressure and the other
rail 34 is of low pressure. The high pressure rail 32 is preferably
maintained at a pressure in the range of about 2000 to about 4000
psia/psig, more preferably at about 3000 psia/psig and the low
pressure rail 34 is preferably maintained at a pressure in the
range of about 100 to about 300 psia/psig, more preferably at about
200 psia/psig.
Pressures of high pressure rail 32 which are greater than about
5000 psig are undesirable because the high pressure pump would
represent waste and because it would be hard to maintain structural
integrity of the system.Iadd., .Iaddend.and pressures of the high
pressure rail 32 which are less than about 2000 .Iadd.psia/psig
.Iaddend.are undesirable because the injector intensifier piston
would have to be of a very large diameter in order to obtain the
proper amplifier ratio.
.[.Pressure.]. .Iadd.Pressures .Iaddend.of the low pressure rail 34
which are greater than about 400 .Iadd.psia/psig .Iaddend.are
undesirable because of excessive valve spring preload requirement
to offset the low pressure acting on the plunger driving the
valve.Iadd., .Iaddend.and pressures of the low pressure rail 34
which are less than about 14.7 psia are undesirable because there
would be cavitation in the passages connecting the spool valve to
the engine valves.
FIG. 3, shows a schematic of associated apparatus of this
invention. The associated equipment is well known in the art and
the elements are identified and associated with multiple cylinders
.[.10a-10f.]. .Iadd.10 .Iaddend.of an engine.
For simplicity, a written description of the well known equipment
and obvious liquid flow paths will not be described in detail as
one skilled in the art can easily construct this associated
equipment without inventive effort. However, it is preferred that
the low pressure pump serving the low pressure rail 34 is a common
gear pump and the high pressure pump serving the high pressure rail
32 is a radial type pump.
As is further known in the art, one skilled in hydraulics and spool
valves can readily position the grooves and associated inlets and
outlets of the spool valve to achieve the desired results.
Industrial Applicability
As stated above, one skilled in the hydraulic and/or valve art can
design the valve, the spool and various passageways after the
preferred timing is known. An example spool movement table is as
follows:
__________________________________________________________________________
STROKE (mm) VOLTAGE EXHAUST VALVE INTAKE VALVE INJECTOR
__________________________________________________________________________
0.5 300 LP closed LP open LP open 1.0 600 HP open, valve actuated.
LP open LP open 1.5 900 HP closed, LP open LP open LP ready to
open. 2.0 1200 LP open LP closed, LP open HP ready to open. 2.5
1500 LP open HP open, valve actuated. LP open 3.0 1800 LP open
actuation completed; LP open HP closed. 3.75 2250 LP open LP open
Start metering 4.32 2600 LP open LP open HP open; Start inj. 5.0
3000 LP open LP open Injection completed
__________________________________________________________________________
Relation to crank angle is as set forth in FIG. 4.
Therefore, when the piezoelectric motor 18 starts to energize at a
low voltage, 300 v. for example, the piezo stack expands 0.025 mm
and moves the spool 24 from rest position .[.1a to position 2a.].
through a 20:1 amplification or area ratio between the piezo disks
and the spool 24. At this position, the exhaust valve low pressure
line 28 is ready to close and the high pressure line 26 is ready to
open.
By increasing the voltage to 600 v. for example, the spool moves to
1 mm position. The exhaust low pressure is fully closed and the
high pressure is open. That actuates the exhaust valve 6 and the
exhaust plunger 38 for as long as the timing event is required.
By switching from high pressure to low pressure, reducing voltage
from 600 v back to 300 v, and allowing the valve momentum to
complete the valve opening cycle, hydraulic power consumption is
reduced. .[.This is an effective method of power
recuperation..].
By increasing the voltage to 900 v, the spool .[.location 1b.].
moves .[.to position 2b.]. and closes the HP line .[.21.]. .Iadd.26
.Iaddend.and at the same time opens low pressure line .[.28'.].
.Iadd.28.Iaddend.. The exhaust valve spring (not shown) shuts the
exhaust valve 6 and completes the exhaust valve actuation. The same
.[.recuperation.]. .Iadd.power reduction .Iaddend.scheme applies
here during the valve closing. The reduction in power consumption
is even more effective in closing than in opening. Further, the
closing .[.recuperation.]. .Iadd.power reduction .Iaddend.will
assist in reducing valve seating velocity.
By increasing the voltage to 1200 v, the spool .[.location 1g.].
moves to .Iadd.a .Iaddend.position .[.2g. The.]. .Iadd.whereby the
.Iaddend.intake valve low pressure line .[.28".]. .Iadd.28
.Iaddend.is ready to close and the high pressure .[.26".].
.Iadd.line 26 .Iaddend.is ready to open.
Further, increasing the voltage to 1500 v fully closes the intake
valve low pressure line and the high pressure line is wide open and
communicates with the passages 42 and 47, thereby actuating the
intake valve 4 through the intake plunger 46. The same
.[.recuperation.]. .Iadd.power reduction .Iaddend.technique
employed for the exhaust valve can be applied for the intake valve
4.
When the voltage increases to 1800 v the spool moves .[.from.].
.Iadd.to a .Iaddend.position .[.1i to 2i. The.]. .Iadd.whereby the
.Iaddend.passage 42 will be shut off and the high pressure line
.[.26".]. .Iadd.26 .Iaddend.will be closed. The low pressure line
.[.28".]. .Iadd.28 .Iaddend.will be open. The intake valve spring
will shut the intake valve 4 and complete the intake valve
actuation.
Other aspects, objects and advantages of this invention can be
obtained from a study of the drawings, the disclosure and the
appended claims.
* * * * *