Title: Engine lubrication system
Abstract: A lubrication system for an engine including a sump for lubricant, a main pump operable to pump lubricant to first lubrication positions within the engine, and an auxiliary lubricant pump also operable to pump lubricant to second lubrication positions within the engine and wherein the auxiliary pump is an electrically driven pump which is controlled by a system controller the output of the auxiliary pump being controlled according to engine operating conditions, the main pump in use, pumping lubricant to the first lubrication positions within the engine along a main lubricant feed line, and the auxiliary pump when operated pumping lubricant to the second lubrication positions within the engine along an auxiliary feed line, and wherein the main and auxiliary feed lines, are connected via a communication passage which includes a closeable communication valve, the communication valve when closed preventing the flow of lubricant from the auxiliary feed line to the first lubrication positions, and when open permitting the flow of lubricant from the auxiliary feed line to the first lubrication positions.
Patent Number: 6,941,922 Issued on 09/13/2005 to Williams, et al.
| Inventors:
|
Williams; David John (Hampton-on-the-Hill, GB);
Black; David Thomas (Birmingham, GB)
|
| Assignee:
|
Dana Automotive Limited (Birmingham, GB)
|
| Appl. No.:
|
437319 |
| Filed:
|
May 13, 2003 |
Foreign Application Priority Data
| Current U.S. Class: |
123/196R; 123/196S; 184/6.22; 184/6.28; 184/6.8 |
| Intern'l Class: |
F01M 001/00 |
| Field of Search: |
123/196 R,196.A,196.S,196.AB
184/63,68,621,622,628
|
References Cited [Referenced By]
U.S. Patent Documents
| 4424665 | Jan., 1984 | Guest et al.
| |
| 4531485 | Jul., 1985 | Murther.
| |
| 4626344 | Dec., 1986 | Fick et al.
| |
| 4629033 | Dec., 1986 | Moore et al.
| |
| 4685066 | Aug., 1987 | Hafele et al.
| |
| 5315825 | May., 1994 | Giberson.
| |
| 5351664 | Oct., 1994 | Rotter et al.
| |
| 5682851 | Nov., 1997 | Breen et al.
| |
| 6213080 | Apr., 2001 | Marsh et al.
| |
| 6644262 | Nov., 2003 | Matsuda et al.
| |
| 6739305 | May., 2004 | Takahara et al.
| |
| Foreign Patent Documents |
| 39 29 078 | Mar., 1991 | DE.
| |
| 0303938 | Feb., 1989 | EP.
| |
| 0408758 | Jan., 1991 | EP.
| |
| 0500487 | Aug., 1992 | EP.
| |
| 1172586 | Jan., 2001 | EP.
| |
| 1 553 885 | Oct., 1979 | GB.
| |
| 57 070907 | May., 1982 | JP.
| |
| 06 200721 | Jul., 1994 | JP.
| |
| 2001/ 241313 | Sep., 2001 | JP.
| |
Primary Examiner: Kamen; Noah P.
Attorney, Agent or Firm: Dykema Gossett PLLC
Claims
1. A lubrication system for an engine including a sump for lubricant, a main
pump operable to pump lubricant to first lubrication positions within the engine,
and an auxiliary lubricant pump operable to pump lubricant to second lubrication
positions, different from said first lubrication positions, within the engine and
wherein the auxiliary pump is an electrically driven pump which is controlled by
a system controller, the output of the auxiliary pump being controlled according
to engine operating conditions, the main pump in use, pumping lubricant to the
first lubrication positions within the engine along a main lubricant feed line,
and the auxiliary pump when operated pumping lubricant to the second lubrication
positions within the engine along an auxiliary feed line, and wherein the main
and auxiliary feed lines, are connected via a communication passage which includes
a closeable communication valve, the communication valve when closed preventing
the flow of lubricant from the auxiliary feed line to the first lubrication positions,
and when open permitting the flow of lubricant from the auxiliary feed line to
the first lubrication positions.
2. A system according to claim 1 wherein the main pump has a linear output relative
to engine speed at least during selected engine operating conditions in which the
main pump is operated and the auxiliary pump is inoperative or operating at a low output.
3. A system according to claim 2 wherein the main pump is mechanically driven
from an output member of the engine.
4. A system according to claim 1 wherein there is provided a main lubricant conditioner
in the main lubricant feed line.
5. A system according to claim 4 wherein the lubricant conditioner includes at
least one of a lubricant filter and a lubricant cooler.
6. A system according to claim 1 wherein there is an auxiliary lubricant conditioner
in the auxiliary feed line.
7. A system according to claim 1 wherein there is a main lubricant inlet to the
main pump and an auxiliary inlet to the auxiliary pump and a passage connecting
the main feed line and the auxiliary inlet, an isolating valve in the connecting
passage which in one position isolates the auxiliary pump inlet from the main feed
line and in another position provides communication between the main feed line
and the auxiliary pump inlet.
8. A system according to claim 7 wherein the isolating valve is a 90° two
position ball valve.
9. A system according to claim 1 wherein the engine includes a main lubricant
gallery from which lubricant passes to the first lubrication positions to lubricate
bearings of the engine crankshaft, and a head gallery from which lubricant passes
to the second lubrication positions to lubricate engine valve operating devices.
10. A system according to claim 9 wherein the engine includes a secondary lubrication
gallery from which lubricant passes to lubrication positions to lubricate and cool
the undersides of pistons of the engine.
11. A system according to claim 10 wherein a control valve is provided which
is selectively operated by the lubrication system controller to allow lubricant
to flow to the secondary lubrication gallery in selected operating conditions.
12. A system according to claim 1 wherein the sump includes an integral mounting
for at least one of the main and auxiliary pumps, and an integral mounting for
a lubricant conditioner.
13. A system according to claim 12 wherein there is a main lubricant inlet to
the main pump and an auxiliary inlet to the auxiliary pump and a passage connecting
the main feed line and the auxiliary inlet, an isolating valve in the connecting
passage which in one position isolates the auxiliary pump inlet from the main feed
line and in another position provides communication between the main feed line
and the auxiliary pump inlet and wherein the sump includes an integral mounting
for the isolating valve.
14. A method of operating a lubrication system for an engine which includes a
sump for lubricant, a main pump operable to pump lubricant along a main feed path
to first lubrication positions within the engine, and an electrically driven auxiliary
lubricant pump operable to pump lubricant along an auxiliary feed path to second
lubrication positions within the engine, and wherein the main and auxiliary feed
lines are connected via a communication passage which includes a closeable communication
valve, the communication valve when closed preventing the flow of lubricant from
the auxiliary feed line to the first lubrication positions, and when open permitting
the flow of lubricant from the auxiliary feed line to the first lubrication positions,
the method including, for selected engine operating conditions, operating the main
pump with the auxiliary pump inoperative or operating to provide a low level output,
and for alternative engine operating conditions operating the auxiliary pump or
operating auxiliary pump to provide a higher output.
15. A method according to claim 14 which includes operating the main pump with
the auxiliary pump inoperative or operative to provide a low level output for engine
speeds lower than a predetermined engine speed, and operating the main pump and
operating or increasing the output of the auxiliary pump for engine speeds higher
than a predetermined engine speed.
16. A method according to claim 14 which includes operating the main pump with
the auxiliary pump inoperative or operating to provide a low level output, and
upon bringing into operation an additional lubricant-using service, continuing
to operate the main pump and operating or increasing the output of the auxiliary pump.
17. A method according to claim 16 wherein the engine includes a main lubricant
gallery from which lubricant passes to the first lubrication positions to lubricate
bearings of the engine crankshaft, and a head gallery from which lubricant passes
to the second lubrication positions to lubricate engine valve operating devices,
and a secondary lubrication gallery from which lubricant passes to lubrication
positions to lubricate and cool the undersides of pistons of the engine, there
being a control valve which is selectively operated by the lubrication system controller
to allow lubricant to flow to the secondary gallery in selected operating conditions,
the method including operating the control valve to permit lubricant pumped by
the main pump to flow to the secondary gallery, and in alternative selected engine
operating conditions operating the control valve to permit lubricant pumped by
the auxiliary pump to flow to the secondary gallery.
18. A method according to claim 16 wherein the engine includes a main lubricant
gallery from which lubricant passes to the first lubrication positions to lubricate
bearings of the engine crankshaft, and a head gallery from which lubricant passes
to the second lubrication positions to lubricate engine valve operating devices
including a variable valve timing device, the method including operating the main
pump with the auxiliary pump inoperative or operating to provide a low output,
when the variable valve timing device is inoperative, and when the variable valve
timing device is operated, operating the main pump and operating or increasing
the output of the auxiliary pump.
19. A method according to claim 14 including prior to engine start-up or upon
main pump failure, operating the auxiliary pump whilst opening the communication
valve to allow the flow of lubricant from the auxiliary feed line to the main feed
line, and in normal engine operation, closing the communication valve so that the
main feed line is fed with lubricant at least primarily from the main pump.
20. A method of operating a lubrication system for an engine including a sump
for lubricant, a main pump operable to pump lubricant to first lubrication positions
within the engine, and an auxiliary lubricant pump operable to pump lubricant to
second lubrication positions, different from said first lubrication positions,
within the engine and wherein the auxiliary pump is an electrically driven pump
which is controlled by a system controller, the output of the auxiliary pump being
controlled according to engine operating conditions, the main pump in use, pumping
lubricant to the first lubrication positions within the engine along a main lubricant
feed line, and the auxiliary pump when operated pumping lubricant to the second
lubrication positions within the engine along an auxiliary feed line, and wherein
the main and auxiliary feed lines, are connected via a communication passage which
includes a closeable communication valve, the communication valve when closed preventing
the flow of lubricant from the auxiliary feed line to the first lubrication positions,
and when open permitting the flow of lubricant from the auxiliary feed line to
the first lubrication positions, wherein in the event that the main pump fails,
operating the auxiliary pump to provide a maximum flow of lubricant to the lubrication positions.
21. A method according to claim 20 which includes providing an output to an engine
management system to result in restriction of engine performance to below a pre-set level.
22. The method of claim 20, further including the steps of providing a lubricant
filter in one of the main lubricant feed line and the auxiliary feed line; sensing
the lubricant pressure in the one lubricant feed line on either side of the filter,
and comparing the pressures, and in the event that the pressure differential exceeds
a threshold value providing a warning signal.
23. A method of operating a lubrication system for an engine which includes a
sump for lubricant, a main pump operable to pump lubricant along a main feed line
to first lubrication positions within the engine, and an electrically driven auxiliary
lubricant pump operable to pump lubricant along an auxiliary feed line to second
lubrication positions, different from said first lubrication positions, within
the engine, and wherein the main and auxiliary feed lines are connected via a communication
passage which includes a closeable communication valve, the communication valve
when closed preventing the flow of lubricant from the auxiliary feed line to the
first lubrication positions, and when open permitting the flow of lubricant from
the auxiliary feed line to the first lubrication positions, the method including,
prior to engine start-up or upon main pump failure, operating the auxiliary pump
whilst opening the communication valve to allow the flow of lubricant from the
auxiliary feed line to the main feed line, and in normal engine operation, closing
the communication valve so that the main feed line is fed with lubricant at least
primarily from the main pump.
24. An engine including a lubrication system including a sump for lubricant,
a main pump operable to pump lubricant to first lubrication positions within the
engine, and an auxiliary lubricant pump operable to pump lubricant to second lubrication
positions, different from said first lubrication positions, within the engine and
wherein the auxiliary pump is an electrically driven pump which is controlled by
a system controller, the output of the auxiliary pump being controlled according
to engine operating conditions, the main pump in use, pumping lubricant to the
first lubrication positions within the engine along a main lubricant feed line,
and the auxiliary pump when operated pumping lubricant to the second lubrication
positions within the engine along an auxiliary feed line, and wherein the main
and auxiliary feed lines, are connected via a communication passage which includes
a closeable communication valve, the communication valve when closed preventing
the flow of lubricant from the auxiliary feed line to the first lubrication positions,
and when open permitting the flow of lubricant from the auxiliary feed line to
the first lubrication positions.
Description
ENGINE LUBRICATION SYSTEM
This application claims priority to United Kingdom Patent Application No. 0211110.2
filed May 15, 2002, the entire disclosure of which is incorporated herein by reference.
1. Background to the Invention
This invention relates to an engine lubrication system and to a method of operating
such a system.
2. Description of the Prior Art
Conventionally engine lubrication systems include a mechanically driven
lubrication pump, the output of which is solely dependent upon the engine speed.
In steady conditions and at lower engine speeds such mechanical pumps work well
and efficiently. However at higher engine speeds, such mechanical pumps tend to
pump lubricant in excess of that which is required for lubrication, making them
inefficient, and in non-steady conditions, for example when the engine is operating
at low speed under heavy load, it is possible that adequate lubrication will not
be provided.
Accordingly it has previously been proposed to utilise an electrically
driven lubrication pump, the output of which can be varied intelligently to match
engine operating conditions. However a straight replacement of the conventional
mechanically driven pump with an electrically driven pump only overcomes some of
the deficiencies of using conventional mechanically driven pumps.
SUMMARY OF THE INVENTION
According to one aspect of the invention we provide a lubrication system
for an engine including a sump for lubricant, a main pump operable to pump lubricant
to first lubrication positions within the engine, and an auxiliary lubricant pump
operable to pump lubricant to second lubrication positions within the engine and
wherein the auxiliary pump is an electrically driven pump which is controlled by
a system controller, the output of the auxiliary pump being controlled according
to engine operating conditions, the main pump in use, pumping lubricant to the
first lubrication positions within the engine along a main lubricant feed line,
and the auxiliary pump when operated pumping lubricant to the second lubrication
positions within the engine along an auxiliary feed line, and wherein the main
and auxiliary feed lines, are connected via a communication passage which includes
a closeable communication valve, the communication valve when closed preventing
the flow of lubricant from the auxiliary feed line to the first lubrication positions,
and when open permitting the flow of lubricant from the auxiliary feed line to
the first lubrication positions.
Thus by providing an auxiliary pump with a variable output, various advantages
may be realised. Moreover, prior to engine start-up, the communication valve may
be opened so that the auxiliary pump may be operated to pump lubricant to the main
gallery via the communication passage to prime the lubrication positions fed by
the main gallery, prior to engine startup.
The size of the main pump may be reduced compared to a similar system of similar
rating because the main pump does not need to be able to satisfy the maximum possible
demand for all engine speeds, as any deficiency may be made up by the auxiliary pump.
Thus the main pump may have a linear output relative to engine speed at least
during usual selected engine operating conditions.
Preferably the main pump is mechanically driven from an output member
of the engine, such as the engine output shaft or crankshaft.
In the main lubricant feed line there may be provided a main lubricant conditioner,
which may include at least one of a lubricant filter and a lubricant cooler, whilst
in the auxiliary feed line, an auxiliary lubricant conditioner may be provided.
There may be a main lubricant inlet to the main pump and an auxiliary inlet
to the auxiliary pump and a passage connecting the main feed line and the auxiliary
inlet, with an isolating valve in the connecting passage. In one position the isolating
valve may isolate the auxiliary pump inlet from the main feed line and in another
position may provide communication between the main feed line and the auxiliary
pump inlet, so that lubricant may be pumped by the main pump into the auxiliary
feed line past the auxiliary pump.
Although any suitable isolating valve may be used, the isolating valve may
be a 90° two position ball valve.
The engine may be of the kind which includes a main lubricant gallery from which
lubricant passes to the first lubrication positions to lubricate bearings of the
engine crankshaft, and a head gallery from which lubricant passes to the second
lubrication positions to lubricate, and operate in some cases, engine valve operating devices.
In some engines there may be a secondary lubrication gallery from which lubricant
passes to lubrication positions to lubricate and cool the undersides of pistons
of the engine. In this case, a control valve may be provided which is selectively
operated by the lubrication system controller to allow lubricant to flow to the
secondary gallery in selected operating conditions.
The sump may include an integral mounting for at least one of the main and auxiliary
pumps, and an integral mounting for a lubricant conditioner, to facilitate packaging
these, and as desired, other, components, such as the isolating valve where provided,
for which an integral mounting may also be provided by the sump.
According to a second aspect of the invention we provide a method of operating
a lubrication system for an engine which includes a sump for lubricant, a main
pump operable to pump lubricant to first lubrication positions within the engine,
and an electrically driven auxiliary lubricant pump operable to pump lubricant
to second lubrication positions within the engine, and wherein the main and auxiliary
feed lines are connected via a communication passage which includes a closeable
communication valve, the communication valve when closed preventing the flow of
lubricant from the auxiliary feed line to the first lubrication positions, and
when open permitting the flow of lubricant from the auxiliary feed line to the
first lubrication positions, the method including, for selected engine operating
conditions, operating the main pump with the auxiliary pump inoperative or operating
to provide a low level output, and for alternative engine operating conditions
operating the auxiliary pump or operating the auxiliary pump to provide a higher
pump output.
The method may include operating the main pump with the auxiliary pump inoperative
or operative to provide a low level output for engine speeds lower than a predetermined
engine speed, and operating the main pump and operating or increasing the output
of the auxiliary pump for engine speeds higher than a predetermined engine speed,
or alternatively the method may include operating the main pump with the auxiliary
pump inoperative or operating to provide a low level output, and upon bringing
into operation an additional lubricant-using service, continuing to operate the
main pump and operating or increasing the output of the auxiliary pump.
Where the engine is of the kind including a main lubricant gallery from which
lubricant passes to the first lubrication positions to lubricate bearings of the
engine crankshaft, and a head gallery from which lubricant passes to the second
lubrication positions to lubricate and in some cases operate engine valve operating
devices, and a secondary lubrication gallery from which lubricant passes to lubrication
positions to lubricate and cool the undersides of pistons of the engine, there
being a control valve which is selectively operated by the lubrication system controller
to allow lubricant to flow to the secondary gallery in selected operating conditions,
and the method may include operating the control valve to permit lubricant pumped
by the main pump to flow to the secondary gallery, and in alternative selected
engine operating conditions operating the control valve to permit lubricant pumped
by the auxiliary pump to flow to the secondary gallery.
Where the engine includes a main lubricant gallery from which lubricant passes
to the first lubrication positions to lubricate bearings of the engine crankshaft,
and a head gallery from which lubricant passes to the, second lubrication positions
to lubricate and in some cases operate engine valve operating devices including
a variable valve timing device, the method may include operating the main pump
with the auxiliary pump inoperative or operating to provide a low output, when
the variable valve timing device is inoperative, and when the variable valve timing
device is operated, operating the main pump and operating or increasing the output
of the auxiliary pump.
In each case, the method may include prior to engine start-up or upon main pump
failure, operating the auxiliary pump whilst opening the communication valve to
allow the flow of lubricant from the auxiliary feed line to the main feed line,
and in normal engine operation, closing the communication valve so that the main
feed line is fed with lubricant at least primarily from the main pump.
According to a third aspect of the invention we provide a method of operating
a lubrication system according to the first aspect of the invention in the event
that the main pump fails including the steps of operating the auxiliary pump to
provide a maximum flow of lubricant to the lubrication positions.
If desired the method of the third aspect of the invention may include providing
an output for an engine management system to result in restriction of engine performance
to below a pre-set level.
According to a fourth aspect of the invention we provide a method of determining
the state of blockage of a lubricant filter to which lubricant is supplied from
a pump, and in which the filter is provided in a lubricant feed line including
the steps of sensing the lubricant pressure in the lubricant feed line either side
of the filter, and comparing the pressures, and in the event that the pressure
differential exceeds a threshold value providing a warning signal.
According to a fifth aspect of the invention we provide a method of operating
a lubrication system for an engine which includes a sump for lubricant, a main
pump operable to pump lubricant along a main feed line to first lubrication positions
within the engine, and an electrically driven auxiliary lubricant pump operable
to pump lubricant along an auxiliary feed line to second lubrication positions
within the engine, and wherein the main and auxiliary feed lines are connected
via a communication passage which includes a closeable communication valve, the
communication valve when closed preventing the flow of lubricant from the auxiliary
feed line to the first lubrication positions, and when open permitting the flow
of lubricant from the auxiliary feed line to the first lubrication positions, the
method including, prior to engine start-up or upon main pump failure, operating
the auxiliary pump whilst opening the communication valve to allow the flow of
lubricant from the auxiliary feed line to the main feed line, and in normal engine
operation, closing the communication valve so that the main feed line is fed with
lubricant at least primarily from the main pump.
According to a sixth aspect of the invention we provide an engine with
a lubrication system according to the first aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be described with reference to the accompanying
drawings which are illustrative diagrams of a lubrication system in accordance
with the present invention.
FIG. 1 is an illustrative diagram of a lubrication system in accordance with
the present invention.
FIG. 2 is a perspective view of a lubrication system in accordance with the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawing there is shown a lubrication system
10
for an engine. The system
10 includes a sump
11 for lubricant, and
a main pump
12 for pumping lubricant from the sump
11 to lubrication
positions in the engine.
The main pump
12 in this example is a pump with a linear output relative
to engine speed at least over a normal engine speed operating range, and although
the main pump
12 may be electrically driven, preferably the pump
12
is mechanically driven from an output member (e.g. crankshaft) of the engine.
The main pump
12 includes a by-pass
14 so that any excess lubricant
the pump
12 is constrained to pump e.g. at higher engine speed by virtue
of being mechanically coupled to the output member of the engine, can be returned
to the sump
11 and thus not used for lubrication. Use of the by-pass
14
in this way represents an inefficiency of operation. A mechanically driven pump
in a conventional arrangement must be able to pump enough lubricant at any engine
speed to meet the maximum demand for lubricant, but the pumping of excess lubricant
unnecessarily increases engine fuel consumption.
In accordance with the invention, the main pump
12 may be of smaller capacity
than would be required for a conventional lubrication system of the same rating,
because an electrically driven and thus variable output auxiliary pump
17
is provided to provide for at least some lubrication, the auxiliary pump
17
having a variable output as demand requires. Any suitable kind of electrically
driven pump
17 may be provided such as for examples only, a gerotor pump,
a ring gear pump or a disc pump.
The main pump
12 pumps lubricant along a main feed line
13 to a
lubricant conditioner
15 which in this example includes a lubricant filter
21 and a lubricant cooler
25 arranged in-line, but in another example
the filter
21 and cooler
25 may be provided in series.
The pumped lubricant from the lubricant conditioner
15 then passes to
a main lubrication gallery
30 of the engine from where the lubricant passes
to first lubrication positions to lubricate bearings and other components of an
engine crankshaft and any turbo charger or other device driven from the engine
exhaust gases. The lubricant then passes under gravity back to the sump
11
for further conditioning and recirculation.
The main pump
12 draws lubricant from the sump
11 via a main lubricant
inlet I
1.
From the main lubricant feed line
13 there is a communication passage
P
1 in which there is provided a two-way control valve
40. In
one position of operation, the control valve
40 permits lubricant to flow
along the passage P
1 to a secondary lubricant gallery
32 from
where the lubricant may pass to lubrication positions
33 at the undersides
of pistons of the engine, for the purposes of cooling and lubricating the undersides
of the pistons. The control valve
40 is controlled by a lubrication system
controller
16.
The main feed line
13 also includes a further communication passage P
2
which connects the main feed line
13 with an auxiliary feed line
22,
the communication passage P
2 including a communication valve
23
which normally is closed, but may be controlled to be opened, by the controller
16, in certain engine operating conditions as will be described below.
The auxiliary pump
17 is also controlled by the controller
16,
and the auxiliary pump
17 when operative, draws lubricant from the sump
11 along an auxiliary inlet I
2. In another embodiment, instead
of the main and auxiliary pumps
12,
17 having separate inlets I
1,
I
2, a combined inlet may be provided.
The auxiliary pump
17 pumps lubricant along an auxiliary lubricant feed
line
22 in which there may be provided a further filter
24.
The main
13 and auxiliary
22 feed lines combine to provide a common
feed path
26 to a head lubrication gallery
35 having second lubrication
positions, for example as shown at
36 to lubricate the engine camshaft (where
provided); and at
37 to provide hydraulic pressure and lubrication to hydraulic
lash adjusters; and at
38 to provide lubrication for (and in some cases
hydraulic pressure to operate) a variable valve timing (VVT) mechanism.
In another example in which the engine is a camless engine, the head gallery
35
may have second lubrication positions for lubricating solenoid operated valves
or the like, as desired.
The control valve
40 in the first communication passage P
1,
when operated in a second position under the control of the controller
16,
may permit lubricant from the auxiliary feed line to flow to the secondary gallery
32, whilst preventing the flow of lubricant from the main feed line
13
to the secondary gallery
32, for the purpose described below.
In the auxiliary inlet I
2, there is provided an isolating valve
18
which may be operated by the system controller
16, to move between two operating
positions. Typically the valve
18 is a two way 90° ball valve, which
may be rotated by a valve drive motor under the control of the controller
16.
In a first operating position as shown in the drawing, the lubricant may pass along
the inlet I
2 from the sump
11 to the auxiliary pump
17,
but in a second operating position, at 90° to the first operating position
for this kind of valve
18, lubricant may also pass from the main inlet Ii
to the auxiliary pump
17, as hereinafter described.
A typical method of operating the lubrication system
10 will now be described.
Prior to engine start-up, e.g. when the engine ignition is switched on, engine
start-up is deferred until the auxiliary pump
17 is operated for a short
period to prime the engine with lubricant. The communication valve
23 in
the second communicating passage P
2 is opened by the controller
16,
and the isolating valve
18 in the auxiliary inlet I
2 is moved
as necessary to the position shown in the drawing. Thus lubricant will be drawn
from the sump
11 through inlet I
2 and pumped by the auxiliary
pump
17 along the auxiliary feed line
22, into the combined feed
path
26, to the head gallery
32 where the lubricant will lubricate
the head components and then flow downwardly under gravity back to the sump
11,
and via the second communicating passage P
2, through communication valve
23, to the main gallery
30 to lubricate the crankshaft etc.
If desired, if a temperature sensor S
1 in the sump
11 or elsewhere
determines that the lubricant temperature is below a predetermined temperature,
say 0° C., prior to operating the auxiliary pump
17, an electrically
operated lubricant heater, for example provided in the sump
11 may be operated
to heat the lubricant to facilitate the lubricant being pumped and flowing around
the lubrication system
10.
A few moments after the auxiliary pump
17 has been operated to prime the
engine with lubricant, the engine may be started.
Because the main pump
12 is mechanically driven by the engine, the
pump
12 will thus become operative, and then the communication valve
23
in the second communication passage P
2 may be closed by the controller
16.
Thus lubricant for the main gallery
30 will be supplied exclusively by
the main pump
12, and lubricant for the head gallery
35 will be supplied
exclusively by the auxiliary pump
17.
As the engine speed increases, the flow of pumped lubricant to the main gallery
30 will be increased linearly. The controller
16 may increase the
output of the auxiliary pump
17 to provide an appropriate increased flow
of lubricant to the head gallery
35 too. However upon any increase in demand
for lubricant, for example if the VVT mechanism is operated, or increase in the
engine load and/or temperature, the controller
16 may increase the output
of the auxiliary pump
17 to compensate.
If the controller
16 determines that the undersides of the pistons require
lubrication and cooling, for example because the engine speed exceeds a maximum
speed and/or the engine load increases and/or the engine temperature increases,
the control valve
40 may be operated either to permit lubricant to flow
to the secondary gallery
32 from the main feed line
13 and/or the
auxiliary feed line
17.
At high engine speeds, the output of the main pump
12 is likely to be
sufficient
to satisfy the entire demand for lubricant in the engine. In this circumstance,
the isolating valve
18 may be rotated by the controller
16 to permit
lubricant pumped by the main pump
12 to flow from the main feed line
13,
through the auxiliary pump
17, (which may free wheel) into the auxiliary
feed line
22 thus to flow to all lubrication positions
30,
33,
36,
37, and
38.
As engine speed decreases, the isolating valve
18 may be moved back to
the position shown in the drawing, and the auxiliary pump
17 again operated
to pump lubricant.
Upon engine shut-down, the main pump
12 will, because it is mechanically
driven from the output member of the engine, cease to operate. However the electrically
driven auxiliary lubrication pump
17 may continue to be operated with the
communication valve
23 in the second communication passageway P
2
open, to permit lubricant to continue to be pumped to the lubrication positions,
particularly where a turbocharger is provided which may have a flywheel which may
continue to rotate due to inertia, for a considerable time after engine shut-down.
If desired, either side of the filter
21 in the main feed line
13,
there may be provided pressure transducers S
2 and S
3 which together
may provide a pressure sensor to give an indication of the extent of blockage of
the filter
21. In the event that the pressure differential across the filter
21 exceeds a predetermined threshold, the controller
16 may be arranged
to give a warning signal, to indicate to a driver that the filter
21 needs
replacement. If desired, such a pressure transducer arrangement may be provided
for the filter
24 in the auxiliary feed line
22 also or alternatively.
It will be appreciated that in the event of main pump
12 failure or partial
failure, which may be determined from the inputs to the controller
16 from
the pressure transducers S
2 and S
3, the controller
16 may
be arranged to open the communication valve
23 in the second communication
passageway P
2, and to increase the output of the auxiliary pump
17
to a maximum so that lubrication and in some cases, hydraulic pressure to all the
lubrication positions may be provided by the auxiliary pump
17. To ensure
that the engine is only then operated within operating parameters for which adequate
lubrication can be provided by the auxiliary pump
17, the controller
16
may issue a signal 0
1 e.g. to any engine management system, to restrict
the operating conditions to which the engine may perform to below a pre-set level.
For example engine speed may be restricted to a low maximum.
When operating in such circumstances, a vehicle in which the engine is provided
may be able to continue to be driven e.g. home, so that repairs to the main pump
12 may then be effected.
If desired the lubrication system controller
16 may be an independent
assembly,
or may be included in part or entirely within the engine management system, or
integrally with one of the pumps
12,
17, or with the isolating valve
18.
Preferably the sump
11 is constructed so as to have integral mountings
for the auxiliary pump
17 and/or the main pump
12, and/or the isolating
valve
18, and/or the lubricant conditioner
15, and/or the lubricant
filter
21 in the auxiliary feed line
22,
50 that the major
operating components of the lubrication system
10 are conveniently packaged
with minimal interconnecting conduits for the lubricant being required. A sump
11 having integral mountings for the auxiliary pump
17, the lubricant
cooler
25 and lubricant filter
21 is illustrated in FIG.
2.
The embodiment described is only an example of how the invention may be performed.
For example in another engine, under-piston lubrication and cooling may not be
required in which case no secondary gallery
32 would be provided. The lubricant
conditioner
15 need not include an oil cooler
25 although this is
preferred and preferably the lubrication system
10 is coordinated with an
engine cooling system to provide for closer control of engine temperature, including
lubricant temperature under different engine operating conditions.
In another embodiment, instead of the main pump
12 primarily supplying
lubricant to the main gallery
30 and the auxiliary pump
17 to the
head gallery
35, the output of both pumps may simply be combined so that
the auxiliary pump
17 supplements the output of the main pump
12
as demand requires.
*
