GB2381294A

GB2381294A - I.c. engine with increased lubricant capacity

Info

Publication number: GB2381294A
Application number: GB0206295A
Authority: GB
Inventors: Howard Lawrence
Original assignee: Perkins Engines Co Ltd
Current assignee: Perkins Engines Co Ltd
Priority date: 2001-03-16
Filing date: 2002-03-18
Publication date: 2003-04-30
Also published as: GB0206298D0; US20020170524A1; GB0206295D0; GB2374635A; GB2374635B; GB0106510D0

Abstract

The engine has a primary lubricant reservoir or sump 37 below the cylinder block 1, and a secondary lubricant reservoir 11 at a side of the cylinder block 1 which may be formed as a pannier oil tank 11 by sealably attaching an apron 2 to a side of the cylinder block 1. An aperture 15 in the secondary lubricant reservoir 11 is closeable by a valve 17, eg a float valve, and is adapted to permit lubricant flow from the secondary lubricant reservoir 11 to the primary lubricant reservoir 37 when open. The secondary lubricant reservoir 11 increases the oil capacity of the cylinder block, while the aperture 15 allows rapid flow of lubricant when required, for example during drainage prior to servicing. Overflow apertures 32 may be provided for the secondary lubricant reservoirs 11. The apron 2 may be provided with cooling elements 33.

Description

238 1 294

1 A CYLINDER BLOCK ASSEMBLY WITH INCREASED LUBRICANT

2 CAPACITY

4 Technical Field

6 This invention relates to a cylinder block assembly 7 for an engine having an increased lubricant capacity 8 and in particular to a cylinder block assembly in 9 which the volume and flow rate of lubricant within 10 the engine is controlled. The invention also relates 11 to a method of lubricating an engine.

13 Background

15 During operation of an engine, a lubricant such as 16 engine oil is pumped from a sump into the working 17 portions of an engine in order to lubricate, clean 18 and cool the engine's moving parts. Excess oil 19 supplied to the moving parts is drained back to the 20 sump along various paths defined in the engine 21 cylinder block and cylinder head.

1 A large volume of lubricating oil is desirable in an 2 engine. For example, where the volume of engine oil 3 is increased, service intervals can be increased 4 thereby minimizing maintenance costs. However, the 5 volume of oil that can be employed in an engine is 6 limited by engine size as, in general, it is 7 desirable to maintain engine size at a minimum while 8 large volumes of oil require large storage reservoirs 9 in an engine.

11 UK Patent specification No 100,345 describes a

12 lubricating system for a car engine comprising a 13 circulating oil tank located beneath a cylinder block 14 of the engine, and a fresh oil tank formed in the 15 side of the block. Filling of the fresh oil tank 16 results in overflow oil passing through a weir to the 17 circulating oil tank. The system includes a first 18 pump to pump oil from the circulating oil tank to the 19 oil circulation system and a second pump which 20 supplies oil from the fresh oil tank to the oil 21 circulation system. While the fresh oil tank 22 provides an extra volume of oil for the engine, the 23 means for supplying the fresh oil to the circulation 24 system necessitates the use of a pump in the supply 25 line as the disposition of the line is such that oil 26 will not flow to the circulating system when the line 27 is open. Moreover, in order for fresh oil to be 28 supplied to the oil circulation system, both pumps 29 need to operate at the same time. These shortcomings 30 result in a lubricating system which is more 31 expensive to manufacture and operate. The present

1 invention sets out to overcome one or more of the 2 disadvantages of the prior art.

4 Summary of the Invention

6 According to the invention there is provided a 7 cylinder block assembly comprising a cylinder block, 8 a primary lubricant reservoir below the cylinder 9 block, a secondary lubricant reservoir at a side of 10 the cylinder block, a fluid passage extending between 11 the primary and secondary lubricant reservoirs, and a 12 valve which is actuable to open and close the fluid 13 passage, wherein the fluid passage is adapted to 14 permit gravitational flow of the lubricant from the 15 secondary lubricant reservoir to the primary 16 lubricant reservoir when open, wherein actuation of 17 the valve is controlled by a level of lubricant in 18 the primary lubricant reservoir.

20 The invention also extends to an engine having such a 21 cylinder block assembly.

23 The invention also extends to a method for 24 lubricating an engine comprising the steps of: 26 - pumping lubricant around the engine from the 27 primary lubricant reservoir) 28 - collecting a proportion of returned lubricant in 29 the secondary lubricant reservoir; and 30 controlling the return of lubricant from the 31 secondary lubricant reservoir through the fluid

1 passage to the primary lubricant reservoir by means 2 of the valve.

4 Brief Description of the Drawings

6 Various embodiments of the invention will now be 7 described, by way of example only, having regard to 8 the accompanying diagrammatic drawings in which: 10 Figure la is a partial transverse cross section 11 through a cylinder block assembly according to one 12 embodiment of the invention, including a cylinder 13 block provided with a secondary lubricant reservoir 14 at a side wall thereof, the cylinder block also being 15 provided with a primary lubricant reservoir and a 16 cylinder head; and 18 Figure lb is a partial transverse cross section 19 through a cylinder block assembly according to 20 another embodiment of the invention, including a 21 cylinder block provided with a secondary lubricant 22 reservoir at a side wall thereof in which the pannier 23 oil tank is defined by the cylinder block and a 24 cylinder block apron.

26 Detailed Description

28 A cylinder block 1 is provided with at least one 29 secondary lubricant reservoir which acts as an engine 30 oil capacitor to increase engine lubricating oil 31 capacity. In the present example, the secondary

1 lubricant reservoir takes the form of a pannier oil 2 tank 11; however the secondary lubricant reservoir 3 can be of any construction that may be adapted by a 4 skilled person in accordance with the present 5 invention.

7 In Fig la, the pannier oil tank 11 is integrally 8 formed in the cylinder block 1 while in Fig lb the 9 pannier oil tank 11 is defined between the cylinder 10 block 1 and a cylinder block apron 2. The 11 illustrated embodiments are described in more detail 12 below, but it is to be understood that the form and 13 construction of the pannier oil tank may be varied in 14 accordance with the present invention.

16 As shown in Fig la, the cylinder block 1 is a casting 17 made up of a cylinder block body 4 and a cylinder 18 block base 5. Two cylinder block side walls 35 and 19 two cylinder block end walls 36 upstand from the 20 cylinder block base 5 (only one side wall 35 and end 21 wall 36 is shown). The cylinder block 1 is provided 22 with a primary oil reservoir in the form of a sump 37 23 attached to the cylinder block base 5. The cylinder 24 block 1 has a cylinder head 8 fitted with a cylinder 25 head cover 9.

27 The side walls 35 are shaped to define a crankcase 28 housing 7 of a crankcase 6 adjacent the cylinder 29 block base 5. A crankshaft 10 is contained within 30 the crankcase 6.

1 The side wall 35 of the cylinder block 1 is formed to 2 define the pannier oil tank 11 between a side wall 3 outer wall 12 and a side wall inner wall 13 adjacent 4 the cylinder block base 5. The pannier oil tank 11 5 is further defined by a bottom wall 14 at the 6 cylinder block base 5. A bottom wall valve opening 7 15 in the bottom wall 14 provides a fluid passage 38 8 between the pannier oil tank 11 and the sump 37. The 9 pannier oil tank 11 is open at a top end 34. The 10 bottom wall 14 may be formed as a separate plate to 11 facilitate core sand removal from the pannier oil 12 tank 11 where the pannier oil tank 11 is cast 13 integrally with the cylinder block 1.

15 The pannier oil tank 11 is adapted to store 16 lubricating oil 16 or other lubricant. The bottom 17 wall valve opening 15 is openable and closeable by a 18 float valve 17 located in the sump 37. The float 19 valve 17 is of substantially conventional 20 construction and is provided with a valve head 18 21 moveable between an open position to allow drainage 22 of oil 16 from the pannier oil tank 11 through the 23 fluid passage 38 and into the sump 37, and a closed 24 position to allow filling of the pannier oil tank 11 25 in accordance with oil levels in the sump 37. The 26 bottom wall valve opening 15 is dimensioned to allow 27 relatively brisk oil flow in the open position. As 28 the lubricant level in the sump 37 increases, the 29 valve 17 closes the aperture 15 when the level of the 30 lubricant 16 reaches a predetermined level.

1 At its open top end 34, the pannier oil tank 11 is 2 adapted to receive lubricating oil 16 through a 3 filler tube 19 defined in the side wall outer wall 4 12. Whilst the float valve 17 is in the open 5 position, oil received via the filler tube 19 will 6 pass through the pannier oil tank 11 and through the 7 valve opening 15 into the sump 37. When the oil 8 level in the sump 37 has reached a predetermined 9 design level, the float valve 17 will close the valve 10 opening 15 and the pannier oil tank 11 will commence 11 to fill.

13 A conventional dipstick (not shown) or sight glass 40 14 is used in conjunction with the pannier oil tank 11 15 to determine when the design quantity of oil has been 16 reached. It is envisaged that the maximum oil level 17 of the engine will be at or just below the open top 18 end 34 of the filler tube 19.

20 When the engine is in operation, oil is received in 21 the pannier oil tank 11 from a cylinder block duct 21 22 which extends between the cylinder head 8 and the 23 pannier oil tank 11 via a cavity 20. The cylinder 24 block duct 21 is located in the cylinder block side 25 wall 35.

27 The apparatus may be configured such that the pannier 28 oil tank 11 is the prime recipient of oil from the 29 various oil return sources in an engine. Those 30 sources may include, for example, a pressure relief 31 valve 24, shown in Fig lb, that may be required to

1 relieve oil pressure in the lubricating oil circuit 2 of the engine, particularly at low engine speeds.

4 It may be found desirable to include, in an engine, 5 more than one float valve 17 or even a series of 6 float valves 17, to cater for the variable engine 7 inclinations that the engine may experience in use.

8 The speed of oil drain from the pannier oil tank 11 9 into the sump 37 that may be required in use or in 10 service may also influence the number and location of 11 float valves 17.

13 The side wall inner wall 13 is provided with an 14 aperture 32 located at the top end 34 of the pannier 15 oil tank 11. The aperture 32 serves as an overflow 16 for the pannier oil tank 11 so that oil can flow from 17 the pannier oil tank 11, through the aperture 32, 18 into the sump 37 when the capacity of the pannier oil 19 tank 11 is exceeded.

21 Fig lb shows an engine including a cylinder block 1 22 with a pannier oil tank 11 in accordance with a 23 second embodiment of the invention. The cylinder 24 block 1 of Fig lb is broadly similar to the cylinder 25 block 1 of Fig la. Accordingly, like numerals 26 indicate like parts. However, in the present 27 embodiment, the pannier oil tank 11 is defined by an 28 apron 2 and the cylinder block side wall 35. More 29 particularly, the pannier oil tank 11 is defined 30 between the crankcase housing 7 and the apron 2.

1 The apron 2 is sealably adhered to the side wall 35 2 to define the pannier oil tank 11. Briefly, the 3 apron 2 is made up of an apron bottom portion 26, an 4 apron cylinder block portion 27 and an apron cylinder 5 head portion 28 attachable to the cylinder head 8.

6 The apron 2 is formed from a metal sheet or other 7 suitable material and is shaped and contoured to 8 complement the side wall 35 of the cylinder block 1.

9 Advantage is thus taken of a natural cavity that 10 exists in the necked region of a conventional 11 crankcase to define, with apron 2, a pannier oil tank 12 11.

14 The apron 2 is folded at the bottom portion 26 to 15 define an elongate box-like beam 30 for reinforcing 16 the apron 2 and the cylinder block 1 to which the 17 apron 2 is adhered. The beam 30 is secured to a 18 cylinder block flange 31 defined at the cylinder 19 block base 5.

21 The apron 2 may be provided with cooling elements 33 22 on its outer surface in the region of the pannier oil 23 tank 11 to facilitate cooling of oil 16 contained 24 within the pannier oil tank 11. The pannier oil tank 25 11 of Fig lb is also provided with a bottom wall 14.

26 However, in the present embodiment, the bottom wall 27 14 is formed by the cylinder block base 5.

29 Accordingly, the bottom wall valve opening 15 of the 30 pannier oil tank 11 and the fluid passage 38 of Fig 31 lb are defined in the cylinder block base 5. The

1 bottom wall valve opening 15 is also openable and 2 closeable by a float valve 17 in the sump 37.

4 The pannier oil tank 11 of Fig lb, like pannier oil 5 tank 11 of Fig la is adapted to receive oil from a 6 filler tube (not shown) and the cylinder block duct 7 21 in communication with the cylinder head 8 via the 8 cavity 20 defined between the apron 2 and the 9 cylinder block 1. In the embodiments of both Figs la 10 and lb the cylinder block duct 21 is in communication 11 with the interior of the cylinder head cover 9 via 12 cylinder head ducts 29 provided in the cylinder head 13 8 itself. The pannier oil tank 11 can also receive 14 oil from miscellaneous sources as described in 15 relation to Fig la.

17 The aperture 32 in the crankcase housing 7 also 18 functions to receive crankcase gases from the 19 crankcase 6.

21 Both embodiments of the invention are provided with a 22 sump oil pick up 22 located in the sump 37 and an oil 23 pump 23, also housed in the sump 37, for pumping oil 24 from the sump 37 to the crankshaft 10. Oil is 25 directed to the crankshaft 10 by a crankshaft oil 26 feed 25 in communication with the oil pump 23 while 27 the pressure relief oil valve 24 is disposed between 28 the pannier oil tank 11 and the crankshaft oil feed 29 25. An oil spray (not shown) in communication with 30 the oil pump 23 can also be provided to assist in 31 piston cooling and lubrication of piston pins and

1 rings and the cylinder block side and end walls 35, 2 36 respectively.

4 The lubricating oil is filtered by an oil filter (not 5 shown) to clean the oil and remove debris therefrom 6 in conventional manner.

8 Industrial Applicability

10 The pannier oil tanks 11 of Figs la and lb operate in 11 a similar manner and operation and use of the 12 invention will now be described in relation to a 13 typical six cylinder 6.0 lithe engine having a 14 pannier oil tank 11 on each cylinder block side wall 15 35. However, it will be appreciated by those skilled 16 in the art that the invention finds application in 17 engines having different numbers of cylinders and 18 different capacities while engines can be provided 19 with one, two or more pannier oil tanks 11 as 20 required.

22 Lubrication oil 16 from engine main and big end 23 bearings and from piston cooling jets and the like is 24 returned to the sump 37 in a substantially 25 conventional manner.

27 Other oil flow from the cylinder head 8, pressure 28 relief valves 24 and engine components including 29 turbo-chargers, camshafts, idler shaft bearings and 30 the like may be returned first to the pannier oil

1 tanks 11 via the cylinder block ducts 21 and the 2 cylinder head ducts 29.

4 In the 6.0 litre engine of the present example, the 5 sump 37 is adapted to receive ten litres of oil while 6 the pannier oil tanks 11 are dimensioned to receive 7 six litres of oil before overflowing into the sump 37 8 through the aperture 32. Maximum oil flow from the 9 pannier oil tanks 11 via bottom wall valve openings 10 15 is restricted to six or less litres per minute.

12 The fluid passage 38 is disposed such that, when 13 open, oil flows under the force of gravity from the 14 pannier oil tank 11 to the sump 37 without the need 15 for an additional pump.

17 The float valve 17 is set at a level such that the 18 bottom wall valve opening 15 is open under least 19 favourable operating conditions when oil levels in 20 the sump 37 are at their lowest levels, due to the 21 high volume of oil 16 in circulation in an engine.

22 Accordingly, the float valve 17 is closed under most 23 operating conditions.

25 As indicated above, the initial volume of oil is fed, 26 prior to engine start-up, into the pannier oil tank 27 11 via the filler tube 19. When the oil level in the 28 pannier oil tank reaches the aperture 32 the 29 additional fed oil overflows through the aperture 30 into the sump 37.

1 At engine start-up, the pannier oil tanks 11 are full 2 under normal conditions. The float valves 17 are 3 closed due to the high oil level in the sump 37.

4 Accordingly, upon engine start up, oil levels in the 5 sump 37 are lowered as oil is pumped around the 6 engine components, enabling the float valve 17 to 7 open to a limited extent.

9 At idle speed oil will circulate at a rate which 10 returns 18 litres of oil per minute to the sump 37 11 and 6.5 litres of oil per minute to the pannier oil 12 tanks 11. If the float valves 17 are closed, and the 13 pannier oil tanks are full, then the 6.5 litres of 14 oil per minute returned to the pannier oil tanks will 15 overflow through the aperture 32 and return to the 16 sump 37. However, under abnormal conditions where 17 the float valves 17 are open, then assuming the float 18 valves 17 are fully opened and sized to permit a flow 19 of 6 litres of oil per minute, the pannier oil tanks 20 11 are filled approximately 12 minutes after start 21 up, based on a net flow of 0.5 litres of oil per 22 minute into the pannier oil tanks.

24 In practice, the float valves 17 are generally 25 completely shut due to high oil levels 16 in the sump 26 37 so that the pannier oil tanks 11 fill at a faster 27 rate.

29 At most engine operating regimes, flow rate of oil 30 returned to the pannier oil tanks 11 greatly exceeds 31 flow rate from the pannier oil tanks 11. Flow rates

1 are calibrated such that, at idle speeds, oil in 2 circulation is insufficient to allow oil levels in 3 the sump 37 to depress to the point where the valves 4 17 will open. As previously described, any overflow 5 from the pannier oil tanks 11 through the apertures 6 32 simply enters circulation in the engine. At 7 running speeds, oil levels in the sump 37 are further 8 depressed due to the increased volume of oil in 9 circulation whereby the float valves 17 may open.

10 Opening of the float valves 17 in such a manner 11 therefore results in a stabilization of oil levels in 12 the pannier oil tanks 11 at a level proportionate to 13 return flow of the oil 16.

15 Oil within the pannier oil tanks 11 is also cooled in 16 the embodiment described in Fig lb due to the cooling 17 elements 33.

19 In short, oil level within the sump 37 is regulated 20 to be at a correct level in accordance with engine 21 requirements at all times due to the presence of the 22 pannier oil tanks 11 and the co-operation of the 23 bottom wall valve openings 15 and float valves 17.

1 Table 1 below summarises the above described oil 2 flows in an engine: 4 TABLE 1

6 Typical Oil Flows Idle Peak Torque/ Rated Speed Cruise Litre/min % Litre/min % Litre/min % Speed-rpm 700 1500 2200 Bearings 17 32 47 Cooling Jet 1 8 13 Return to 18 73% 40 44.1% 60 47.3% sump Turbo 3 4.2 4.5 Relief valve 30 40 Head/valve 1 2 2 gear Bypass filter 1 8 11.5 Miscellaneous 1. 5 6.4 8.7 Return to 6.527% 50.6 55.9% 66.7 52.7% pannier oil tanks (11) Total flow 24.5100% 90.6 100% 126.7 100% 9 As indicated above, where the engine is running the 10 volume of oil 16 in circulation results in oil levels 11 in the sump 37 being lowered so that the float valves 12 17 are partially opened. However' when the engine is

1 stopped, oil in circulation within the engine is 2 returned to the sump 37 and the pannier oil tanks 11 3 in proportions relative to the engine operating speed 4 immediately prior to shut down. The float valves 17 5 remain open until the sump 37 is at least partially 6 filed with oil 16. In practice, return of oil 16 to 7 the sump 37 occurs in advance of return of oil 16 to 8 the pannier oil tanks 11 due to longer return paths 9 from pannier oil tank filling sources, such as the 10 cylinder head 8. When the float valves 17 are 11 closed, the oil level in the sump 37 continues to 12 rise to a normal level due to the large volume of 13 sump return oil 16 in circulation.

15 When servicing the engine, oil drain may be achieved 16 through a sump plug or a suction tube into the sump 17 37. At a critical drainage level, the float valves 18 17 are opened thereby permitting the pannier oil 19 tanks 11 also to drain.

21 On refilling, the pannier oil tanks 11 are filled 22 through the filler tube 19 and hence the sump 37 23 becomes filled via the bottom wall valve opening 15.

24 If an excessive filling rate is used, the oil tank 25 panniers 11 simply overflow into the sump 37 via the 26 apertures 32 as previously described.

28 The invention finds application in engines where it 29 is desired to incorporate an oil capacitor to 30 supplement the oil sump without detriment to engine 31 servicing efficiency and without compromising oil

1 cleanliness and durability within the engine during 2 operation.

4 The invention is not limited to the embodiments 5 herein before described which may be varied in both 6 construction and detail.

Claims

1 CLAIMS

3 1. A cylinder block assembly comprising a cylinder 4 block, a primary lubricant reservoir below the 5 cylinder block, a secondary lubricant reservoir at a 6 side of the cylinder block, a fluid passage extending 7 between the primary and secondary lubricant 8 reservoirs, and a valve which is actuable to open and 9 close the fluid passage, wherein the fluid passage is 10 adapted to permit gravitational flow of the lubricant 11 from the secondary lubricant reservoir to the primary 12 lubricant reservoir when open, wherein actuation of 13 the valve is controlled by a level of lubricant in 14 the primary lubricant reservoir.

16

2. A cylinder block assembly as claimed in Claim 1

17 wherein the valve is a float valve.

19

3. A cylinder block assembly as claimed in Claim 1 20 or Claim 2, wherein the fluid passage comprises an 21 aperture in the secondary lubricant reservoir.

23

4. A cylinder block assembly as claimed in any 24 preceding Claim, further including a cylinder head 25 and a cylinder head cover on the cylinder head, 26 wherein the secondary lubricant reservoir is 27 communicable by means of at least one duct with an 28 interior of the cylinder head cover.

30

5. A cylinder block assembly as claimed in any 31 preceding Claim, further including a crankcase above

1 the primary lubricant reservoir, wherein the 2 secondary lubricant reservoir is provided with an 3 overflow aperture in a side wall thereof communicable 4 with the crankcase.

6

6. A cylinder block assembly as claimed in any of 7 Claims 1 to 5, wherein the secondary lubricant 8 reservoir is defined between a wall of the cylinder 9 block and an apron sealably mounted on the cylinder 10 block.

12

7. A cylinder block assembly as claimed in any of 13 Claims 1 to 5, wherein the secondary lubricant 14 reservoir is defined between an outer wall and an 15 inner wall of the cylinder block.

17

8. An engine comprising a cylinder block assembly as 18 claimed in any of Claims 1 to 7.

20

9. A method for lubricating an engine having a 21 cylinder block, a primary lubricant reservoir below 22 the cylinder block and a secondary lubricant 23 reservoir, comprising the steps of: 24 - pumping lubricant around the engine from the 25 primary lubricant reservoir; 26 - collecting a proportion of returned lubricant in 27 the secondary lubricant reservoir; and 28 - controlling the return of lubricant from the 29 secondary lubricant reservoir under gravity to the 30 primary lubricant reservoir.

1

10. A method as claimed in Claim 9, wherein the 2 return of lubricant from the secondary lubricant 3 reservoir to the primary lubricant reservoir is 4 controlled by a float valve, such that return of 5 lubricant is prevented when the lubricant level in 6 the primary lubricant reservoir is above a 7 predetermined level, and return of lubricant is 8 allowed when the lubricant level in the primary 9 lubricant reservoir is below the predetermined level.

11

11. A cylinder block assembly substantially as 12 hereinbefore described with reference to the 13 drawings.

15

12. A method for lubricating an engine substantially 16 as hereinbefore described with reference to the 17 drawings.