U.S. patent application number 10/097729 was filed with the patent office on 2002-11-21 for cylinder block assembly with increased lubricant capacity.
Invention is credited to Lawrence, Howard J..
Application Number | 20020170524 10/097729 |
Document ID | / |
Family ID | 9910818 |
Filed Date | 2002-11-21 |
United States Patent
Application |
20020170524 |
Kind Code |
A1 |
Lawrence, Howard J. |
November 21, 2002 |
Cylinder block assembly with increased lubricant capacity
Abstract
In an internal combustion engine, a large volume of lubricant is
desirable to increase service intervals and thus reduce maintenance
costs. Large lubricant volumes typically require an undesirable
increase in engine size. A cylinder block assembly for an internal
combustion engine in accordance with this invention comprises a
cylinder block, a primary lubricant reservoir or sump below the
cylinder block, and a secondary lubricant reservoir at a side of
the cylinder block. The secondary lubricant reservoir may be formed
as a pannier oil tank by sealably attaching an apron to a side of
the cylinder block. A fluid passage extending between the secondary
lubricant reservoir and the primary lubricant reservoir is
closeable by a valve and is adapted to permit lubricant flow from
the secondary lubricant reservoir to the primary lubricant
reservoir when open. The secondary lubricant reservoir increases
the oil capacity of the cylinder block.
Inventors: |
Lawrence, Howard J.;
(Shirley, GB) |
Correspondence
Address: |
CATERPILLAR INC.
100 N.E. ADAMS STREET
PATENT DEPT.
PEORIA
IL
616296490
|
Family ID: |
9910818 |
Appl. No.: |
10/097729 |
Filed: |
March 14, 2002 |
Current U.S.
Class: |
123/196R |
Current CPC
Class: |
F01M 11/03 20130101;
F01M 2011/0058 20130101; F01M 2011/0033 20130101; F01M 11/061
20130101; F02B 67/00 20130101; F02F 7/0043 20130101 |
Class at
Publication: |
123/196.00R |
International
Class: |
F01M 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 16, 2001 |
GB |
0106510.1 |
Claims
What is claimed is:
1. A cylinder block assembly comprising a cylinder block, a primary
lubricant reservoir below the cylinder block, a secondary lubricant
reservoir at a side of the cylinder block, a fluid passage
extending between the primary and secondary lubricant reservoirs,
and a valve that can be actuated to open and close the fluid
passage, wherein the fluid passage is adapted to permit
gravitational flow of the lubricant from the secondary lubricant
reservoir to the primary lubricant reservoir when open, wherein
actuation of the valve is controlled by a level of lubricant in the
primary lubricant reservoir.
2. A cylinder block assembly as set forth in claim 1, wherein the
valve is a float valve.
3. A cylinder block as set forth in claim 1, wherein the fluid
passage comprises an aperture in the secondary lubricant
reservoir.
4. A cylinder block assembly as set forth in claim 1, further
including a cylinder head and a cylinder head cover on the cylinder
head, wherein the secondary lubricant reservoir communicates at
least one duct with an interior of the cylinder head cover.
5. A cylinder block assembly as set forth in claim 5, wherein the
valve is a float valve.
6. A cylinder block assembly as set forth in claim 1, further
including a crankcase above the primary lubricant reservoir,
wherein the secondary lubricant reservoir is provided with an
overflow aperture in a side wall thereof communicable with the
crankcase.
7. A cylinder block assembly as set forth in claim 1, further
including a crankcase above the primary lubricant reservoir,
wherein the secondary lubricant reservoir is provided with an
overflow aperture in a side wall thereof communicable with the
crankcase.
8. A cylinder block assembly as set forth in claim 1, wherein the
secondary lubricant reservoir is defined between a wall of the
cylinder block and an apron sealably mounted on the cylinder
block.
9. A cylinder block assembly as set forth in claim 8, wherein the
valve is a float valve.
10. A cylinder block assembly as set forth in claim 4, wherein the
secondary lubricant reservoir is defined between a wall of the
cylinder block and an apron sealably mounted on the cylinder
block.
11. A cylinder block assembly as set forth in claim 10, wherein the
valve is a float valve.
12. A cylinder block assembly as claimed in claim 1, wherein the
secondary lubricant reservoir is defined between an outer wall and
an inner wall of the cylinder block.
13. A cylinder block assembly as set forth in claim 14, wherein the
valve is a float valve.
14. A cylinder block assembly as set forth in claim 1, wherein the
secondary lubricant reservoir is defined between an outer wall and
an inner wall of the cylinder block.
15. A cylinder block assembly as set forth in claim 16, wherein the
valve is a float valve.
16. A cylinder block assembly as set forth in claim 1, wherein said
valve is actuated to close the fluid passage when the lubricant
level in the primary lubricant reservoir is above a predetermined
level, and wherein said valve is actuated to open the fluid passage
when the lubricant level in the primary lubricant reservoir is
below the predetermined level.
17. A cylinder block assembly comprising a cylinder block, a
primary lubricant reservoir below the cylinder block, a secondary
lubricant reservoir at a side of the cylinder block, a fluid
passage extending between the primary and secondary lubricant
reservoirs, and a valve that can be actuated to open and close the
fluid passage, wherein the fluid passage is adapted to permit
gravitational flow of the lubricant from the secondary lubricant
reservoir to the primary lubricant reservoir when open, wherein
said valve is actuated to close the fluid passage when the
lubricant level in the primary lubricant reservoir is above a
predetermined level, and wherein said valve is actuated to open the
fluid passage when the lubricant level in the primary lubricant
reservoir is below the predetermined level.
18. An engine comprising a cylinder block assembly and a cylinder
head mounted to said cylinder block assembly, wherein said cylinder
block assembly comprises a cylinder block assembly as set forth in
claim 1.
19. A method for lubricating an engine having a cylinder block, a
primary lubricant reservoir below the cylinder block and a
secondary lubricant reservoir, comprising the steps of: pumping
lubricant around the engine from the primary lubricant reservoir;
collecting a proportion of returned lubricant in the secondary
lubricant reservoir; and controlling the return of lubricant from
the secondary lubricant reservoir under gravity to the primary
lubricant reservoir.
20. A method as set forth in claim 19, wherein the return of
lubricant from the secondary lubricant reservoir to the primary
lubricant reservoir is controlled by a float valve, such that
return of lubricant is prevented when the lubricant level in the
primary lubricant reservoir is above a predetermined level, and
return of lubricant is allowed when the lubricant level in the
primary lubricant reservoir is below the predetermined level.
Description
TECHNICAL FIELD
[0001] This invention relates to a cylinder block assembly for an
engine having an increased lubricant capacity and in particular to
a cylinder block assembly in which the volume and flow rate of
lubricant within the engine is controlled. The invention also
relates to a method of lubricating an engine.
BACKGROUND
[0002] During operation of an engine, a lubricant such as engine
oil is pumped from a sump into the working portions of an engine in
order to lubricate, clean and cool the engine's moving parts.
Excess oil supplied to the moving parts is drained back to the sump
along various paths defined in the engine cylinder block and
cylinder head.
[0003] A large volume of lubricating oil is desirable in an engine.
For example, where the volume of engine oil is increased, service
intervals can be increased thereby minimizing maintenance costs.
However, the volume of oil that can be employed in an engine is
limited by engine size as, in general, it is desirable to maintain
engine size at a minimum while large volumes of oil require large
storage reservoirs in an engine.
[0004] UK Patent specification No 100,345 describes a lubricating
system for a car engine comprising a circulating oil tank located
beneath a cylinder block of the engine, and a fresh oil tank formed
in the side of the block. Filling of the fresh oil tank results in
overflow oil passing through a weir to the circulating oil tank.
The system includes a first pump to pump oil from the circulating
oil tank to the oil circulation system and a second pump which
supplies oil from the fresh oil tank to the oil circulation system.
While the fresh oil tank provides an extra volume of oil for the
engine, the means for supplying the fresh oil to the circulation
system necessitates the use of a pump in the supply line as the
disposition of the line is such that oil will not flow to the
circulating system when the line is open. Moreover, in order for
fresh oil to be supplied to the oil circulation system, both pumps
need to operate at the same time. These shortcomings result in a
lubricating system which is more expensive to manufacture and
operate. The present invention sets out to overcome one or more of
the disadvantages of the prior art.
SUMMARY OF THE INVENTION
[0005] According to the invention there is provided a cylinder
block assembly comprising a cylinder block, a primary lubricant
reservoir below the cylinder block, a secondary lubricant reservoir
at a side of the cylinder block, a fluid passage extending between
the primary and secondary lubricant reservoirs, and a valve which
can be actuated to open and close the fluid passage, wherein the
fluid passage is adapted to permit gravitational flow of the
lubricant from the secondary lubricant reservoir to the primary
lubricant reservoir when open, wherein actuation of the valve is
controlled by a level of lubricant in the primary lubricant
reservoir.
[0006] The invention also extends to an engine having such a
cylinder block assembly.
[0007] The invention also extends to a method for lubricating an
engine comprising the steps of:
[0008] pumping lubricant around the engine from the primary
lubricant reservoir;
[0009] collecting a proportion of returned lubricant in the
secondary lubricant reservoir; and
[0010] controlling the return of lubricant from the secondary
lubricant reservoir through the fluid passage to the primary
lubricant reservoir by means of the valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Various embodiments of the invention will now be described,
by way of example only, having regard to the accompanying
diagrammatic drawings in which:
[0012] FIG. 1a is a partial transverse cross section through a
cylinder block assembly according to one embodiment of the
invention, including a cylinder block provided with a secondary
lubricant reservoir at a side wall thereof, the cylinder block also
being provided with a primary lubricant reservoir and a cylinder
head; and
[0013] FIG. 1b is a partial transverse cross section through a
cylinder block assembly according to another embodiment of the
invention, including a cylinder block provided with a secondary
lubricant reservoir at a side wall thereof in which the pannier oil
tank is defined by the cylinder block and a cylinder block
apron.
DETAILED DESCRIPTION
[0014] A cylinder block 1 is provided with at least one secondary
lubricant reservoir which acts as an engine oil capacitor to
increase engine lubricating oil capacity. In the present example,
the secondary lubricant reservoir takes the form of a pannier oil
tank 11; however the secondary lubricant reservoir can be of any
construction that may be adapted by a skilled person in accordance
with the present invention.
[0015] In FIG. 1a, the pannier oil tank 11 is integrally formed in
the cylinder block 1 while in FIG. 1b the pannier oil tank 11 is
defined between the cylinder block 1 and a cylinder block apron 2.
The illustrated embodiments are described in more detail below, but
it is to be understood that the form and construction of the
pannier oil tank may be varied in accordance with the present
invention.
[0016] As shown in FIG. 1a, the cylinder block 1 is a casting made
up of a cylinder block body 4 and a cylinder block base 5. Two
cylinder block side walls 35 and two cylinder block end walls 36
upstand from the cylinder block base 5 (only one side wall 35 and
end wall 36 is shown). The cylinder block 1 is provided with a
primary oil reservoir in the form of a sump 37 attached to the
cylinder block base 5. The cylinder block 1 has a cylinder head 8
fitted with a cylinder head cover 9.
[0017] The side walls 35 are shaped to define a crankcase housing 7
of a crankcase 6 adjacent the cylinder block base 5. A crankshaft
10 is contained within the crankcase 6.
[0018] The side wall 35 of the cylinder block 1 is formed to define
the pannier oil tank 11 between a side wall outer wall 12 and a
side wall inner wall 13 adjacent the cylinder block base 5. The
pannier oil tank 11 is further defined by a bottom wall 14 at the
cylinder block base 5. A bottom wall valve opening 15 in the bottom
wall 14 provides a fluid passage 38 between the pannier oil tank 11
and the sump 37. The pannier oil tank 11 is open at a top end 34.
The bottom wall 14 may be formed as a separate plate to facilitate
core sand removal from the pannier oil tank 11 where the pannier
oil tank 11 is cast integrally with the cylinder block 1.
[0019] The pannier oil tank 11 is adapted to store lubricating oil
16 or other lubricant. The bottom wall valve opening 15 is openable
and closeable by a float valve 17 located in the sump 37. The float
valve 17 is of substantially conventional construction and is
provided with a valve head 18 moveable between an open position to
allow drainage of oil 16 from the pannier oil tank 11 through the
fluid passage 38 and into the sump 37, and a closed position to
allow filling of the pannier oil tank 11 in accordance with oil
levels in the sump 37. The bottom wall valve opening 15 is
dimensioned to allow relatively brisk oil flow in the open
position. As the lubricant level in the sump 37 increases, the
valve 17 closes the aperture 15 when the level of the lubricant 16
reaches a predetermined level.
[0020] At its open top end 34, the pannier oil tank 11 is adapted
to receive lubricating oil 16 through a filler tube 19 defined in
the side wall outer wall 12. Whilst the float valve 17 is in the
open position, oil received via the filler tube 19 will pass
through the pannier oil tank 11 and through the valve opening 15
into the sump 37. When the oil level in the sump 37 has reached a
predetermined design level, the float valve 17 will close the valve
opening 15 and the pannier oil tank 11 will commence to fill.
[0021] A conventional dipstick (not shown) or sight glass 40 is
used in conjunction with the pannier oil tank 11 to determine when
the design quantity of oil has been reached. It is envisaged that
the maximum oil level of the engine will be at or just below the
open top end 34 of the filler tube 19.
[0022] When the engine is in operation, oil is received in the
pannier oil tank 11 from a cylinder block duct 21 which extends
between the cylinder head 8 and the pannier oil tank 11 via a
cavity 20. The cylinder block duct 21 is located in the cylinder
block side wall 35.
[0023] The apparatus may be configured such that the pannier oil
tank 11 is the prime recipient of oil from the various oil return
sources in an engine. Those sources may include, for example, a
pressure relief valve 24, shown in FIG. 1b, that may be required to
relieve oil pressure in the lubricating oil circuit of the engine,
particularly at low engine speeds.
[0024] It may be found desirable to include, in an engine, more
than one float valve 17 or even a series of float valves 17, to
cater for the variable engine inclinations that the engine may
experience in use. The speed of oil drain from the pannier oil tank
11 into the sump 37 that may be required in use or in service may
also influence the number and location of float valves 17.
[0025] The side wall inner wall 13 is provided with an aperture 32
located at the top end 34 of the pannier oil tank 11. The aperture
32 serves as an overflow for the pannier oil tank 11 so that oil
can flow from the pannier oil tank 11, through the aperture 32,
into the sump 37 when the capacity of the pannier oil tank 11 is
exceeded.
[0026] FIG. 1b shows an engine including a cylinder block 1 with a
pannier oil tank 11 in accordance with a second embodiment of the
invention. The cylinder block 1 of FIG. 1b is broadly similar to
the cylinder block 1 of FIG. 1a. Accordingly, like numerals
indicate like parts. However, in the present embodiment, the
pannier oil tank 11 is defined by an apron 2 and the cylinder block
side wall 35. More particularly, the pannier oil tank 11 is defined
between the crankcase housing 7 and the apron 2.
[0027] The apron 2 is sealably adhered to the side wall 35 to
define the pannier oil tank 11. Briefly, the apron 2 is made up of
an apron bottom portion 26, an apron cylinder block portion 27 and
an apron cylinder head portion 28 attachable to the cylinder head
8. The apron 2 is formed from a metal sheet or other suitable
material and is shaped and contoured to complement the side wall 35
of the cylinder block 1. Advantage is thus taken of a natural
cavity that exists in the necked region of a conventional crankcase
to define, with apron 2, a pannier oil tank 11.
[0028] The apron 2 is folded at the bottom portion 26 to define an
elongate box-like beam 30 for reinforcing the apron 2 and the
cylinder block 1 to which the apron 2 is adhered. The beam 30 is
secured to a cylinder block flange 31 defined at the cylinder block
base 5.
[0029] The apron 2 may be provided with cooling elements 33 on its
outer surface in the region of the pannier oil tank 11 to
facilitate cooling of oil 16 contained within the pannier oil tank
11. The pannier oil tank 11 of FIG. 1b is also provided with a
bottom wall 14. However, in the present embodiment, the bottom wall
14 is formed by the cylinder block base 5.
[0030] Accordingly, the bottom wall valve opening 15 of the pannier
oil tank 11 and the fluid passage 38 of FIG. 1b are defined in the
cylinder block base 5. The bottom wall valve opening 15 is also
openable and closeable by a float valve 17 in the sump 37.
[0031] The pannier oil tank 11 of FIG. 1b, like pannier oil tank 11
of FIG. 1a is adapted to receive oil from a filler tube (not shown)
and the cylinder block duct 21 in communication with the cylinder
head 8 via the cavity 20 defined between the apron 2 and the
cylinder block 1. In the embodiments of both FIGS. 1a and 1b the
cylinder block duct 21 is in communication with the interior of the
cylinder head cover 9 via cylinder head ducts 29 provided in the
cylinder head 8 itself. The pannier oil tank 11 can also receive
oil from miscellaneous sources as described in relation to FIG.
1a.
[0032] The aperture 32 in the crankcase housing 7 also functions to
receive crankcase gases from the crankcase 6.
[0033] Both embodiments of the invention are provided with a sump
oil pick up 22 located in the sump 37 and an oil pump 23, also
housed in the sump 37, for pumping oil from the sump 37 to the
crankshaft 10. Oil is directed to the crankshaft 10 by a crankshaft
oil feed 25 in communication with the oil pump 23 while the
pressure relief oil valve 24 is disposed between the pannier oil
tank 11 and the crankshaft oil feed 25. An oil spray (not shown) in
communication with the oil pump 23 can also be provided to assist
in piston cooling and lubrication of piston pins and rings and the
cylinder block side and end walls 35, 36 respectively.
[0034] The lubricating oil is filtered by an oil filter (not shown)
to clean the oil and remove debris therefrom in conventional
manner.
INDUSTRIAL APPLICABILITY
[0035] The pannier oil tanks 11 of FIGS. 1a and 1b operate in a
similar manner and operation and use of the invention will now be
described in relation to a typical six cylinder 6.0 liter engine
having a pannier oil tank 11 on each cylinder block side wall 35.
However, it will be appreciated by those skilled in the art that
the invention finds application in engines having different numbers
of cylinders and different capacities while engines can be provided
with one, two or more pannier oil tanks 11 as required.
[0036] Lubrication oil 16 from engine main and big end bearings and
from piston cooling jets and the like is returned to the sump 37 in
a substantially conventional manner.
[0037] Other oil flow from the cylinder head 8, pressure relief
valves 24 and engine components including turbo-chargers,
camshafts, idler shaft bearings and the like may be returned first
to the pannier oil tanks 11 via the cylinder block ducts 21 and the
cylinder head ducts 29.
[0038] In the 6.0 liter engine of the present example, the sump 37
is adapted to receive ten liters of oil while the pannier oil tanks
11 are dimensioned to receive six liters of oil before overflowing
into the sump 37 through the aperture 32. Maximum oil flow from the
pannier oil tanks 11 via bottom wall valve openings 15 is
restricted to six or less liters per minute.
[0039] The fluid passage 38 is disposed such that, when open, oil
flows under the force of gravity from the pannier oil tank 11 to
the sump 37 without the need for an additional pump.
[0040] The float valve 17 is set at a level such that the bottom
wall valve opening 15 is open under least favorable operating
conditions when oil levels in the sump 37 are at their lowest
levels, due to the high volume of oil 16 in circulation in an
engine. Accordingly, the float valve 17 is closed under most
operating conditions.
[0041] As indicated above, the initial volume of oil is fed, prior
to engine start-up, into the pannier oil tank 11 via the filler
tube 19. When the oil level in the pannier oil tank reaches the
aperture 32 the additional fed oil overflows through the aperture
into the sump 37.
[0042] At engine start-up, the pannier oil tanks 11 are full under
normal conditions. The float valves 17 are closed due to the high
oil level in the sump 37.
[0043] Accordingly, upon engine start up, oil levels in the sump 37
are lowered as oil is pumped around the engine components, enabling
the float valve 17 to open to a limited extent.
[0044] At idle speed oil will circulate at a rate which returns 18
liters of oil per minute to the sump 37 and 6.5 liters of oil per
minute to the pannier oil tanks 11. If the float valves 17 are
closed, and the pannier oil tanks are full, then the 6.5 liters of
oil per minute returned to the pannier oil tanks will overflow
through the aperture 32 and return to the sump 37. However, under
abnormal conditions where the float valves 17 are open, then
assuming the float valves 17 are fully opened and sized to permit a
flow of 6 liters of oil per minute, the pannier oil tanks 11 are
filled approximately 12 minutes after start up, based on a net flow
of 0.5 liters of oil per minute into the pannier oil tanks.
[0045] In practice, the float valves 17 are generally completely
shut due to high oil levels 16 in the sump 37 so that the pannier
oil tanks 11 fill at a faster rate.
[0046] At most engine operating regimes, flow rate of oil returned
to the pannier oil tanks 11 greatly exceeds flow rate from the
pannier oil tanks 11. Flow rates are calibrated such that, at idle
speeds, oil in circulation is insufficient to allow oil levels in
the sump 37 to depress to the point where the valves 17 will open.
As previously described, any overflow from the pannier oil tanks 11
through the apertures 32 simply enters circulation in the engine.
At running speeds, oil levels in the sump 37 are further depressed
due to the increased volume of oil in circulation whereby the float
valves 17 may open. Opening of the float valves 17 in such a manner
therefore results in a stabilization of oil levels in the pannier
oil tanks 11 at a level proportionate to return flow of the oil
16.
[0047] Oil within the pannier oil tanks 11 is also cooled in the
embodiment described in FIG. 1b due to the cooling elements 33.
[0048] In short, oil level within the sump 37 is regulated to be at
a correct level in accordance with engine requirements at all times
due to the presence of the pannier oil tanks 11 and the
co-operation of the bottom wall valve openings 15 and float valves
17.
[0049] Table 1 below summarizes the above described oil flows in an
engine:
1TABLE 1 Typical Oil Flows Peak Torque/ Idle Cruise Rated Speed
Litre/min % Litre/min % Litre/min % Speed - rpm 700 1500 2200
Bearings 17 32 47 Cooling Jet 1 8 13 Return to sump 18 73% 40 44.1%
60 47.3% Turbo 3 4.2 4.5 Relief valve 0 30 40 Head/valve gear 1 2 2
Bypass filter 1 8 11.5 Miscellaneous 1.5 6.4 8.7 Return to pannier
6.5 27% 50.6 55.9% 66.7 52.7% oil tanks (11) Total flow 24.5 100%
90.6 100% 126.7 100%
[0050] As indicated above, where the engine is running the volume
of oil 16 in circulation results in oil levels in the sump 37 being
lowered so that the float valves 17 are partially opened. However,
when the engine is stopped, oil in circulation within the engine is
returned to the sump 37 and the pannier oil tanks 11 in proportions
relative to the engine operating speed immediately prior to shut
down. The float valves 17 remain open until the sump 37 is at least
partially filed with oil 16. In practice, return of oil 16 to the
sump 37 occurs in advance of return of oil 16 to the pannier oil
tanks 11 due to longer return paths from pannier oil tank filling
sources, such as the cylinder head 8. When the float valves 17 are
closed, the oil level in the sump 37 continues to rise to a normal
level due to the large volume of sump return oil 16 in
circulation.
[0051] When servicing the engine, oil drain may be achieved through
a sump plug or a suction tube into the sump 37. At a critical
drainage level, the float valves 17 are opened thereby permitting
the pannier oil tanks 11 also to drain.
[0052] On refilling, the pannier oil tanks 11 are filled through
the filler tube 19 and hence the sump 37 becomes filled via the
bottom wall valve opening 15. If an excessive filling rate is used,
the oil tank panniers 11 simply overflow into the sump 37 via the
apertures 32 as previously described.
[0053] The invention finds application in engines where it is
desired to incorporate an oil capacitor to supplement the oil sump
without detriment to engine servicing efficiency and without
compromising oil cleanliness and durability within the engine
during operation.
[0054] The invention is not limited to the embodiments herein
before described which may be varied in both construction and
detail.
* * * * *