NL2036162B1

NL2036162B1 - An internal combustion system comprising a lubrication circuit

Info

Publication number: NL2036162B1
Application number: NL2036162A
Authority: NL
Inventors: Johannes Maria Slotman Jeroen
Original assignee: Daf Trucks Nv
Priority date: 2023-11-01
Filing date: 2023-11-01
Publication date: 2025-05-13

Abstract

TITLE: An internal combustion system comprising a lubrication circuit In one aspect, it is aimed to provide an internal combustion system comprising a lubrication circuit in ﬂuid communication with a lubricant pump and provided for lubrication of a crank train in a cylinder block of said internal combustion system, and for lubrication of a valve train in a cylinder head of said internal combustion system, said cylinder head mounted to said cylinder block. The lubrication circuit comprises at least one supply channel in said cylinder block coupling said lubricant pump to a ﬁrst lubricant gallery in said cylinder block that provides lubricant towards said crank train. The supply channel is ﬂuidly coupled to a continued supply channel provided in said cylinder head that connects to a second gallery that provides lubricant towards said valve train; the supply channel and/or said continued supply channel traverses a coolant duct that is in thermal contact with said supply channel and/or continued supply channel, in order to provide a reduced lubricant temperature to said valve train.

Description

P135409NL00-DAF0465

TITLE: AN INTERNAL COMBUSTION SYSTEM COMPRISING A

LUBRICATION CIRCUIT

DESCRIPTION Field of invention

The invention relates to an internal combustion system comprising a lubrication circuit. More in particular, the invention relates to an internal combustion system comprising a lubrication circuit in fluid communication with a lubricant pump and provided for lubrication of a crank train in a cylinder block of said internal combustion system, and for lubrication of a valve train in a cylinder head of said internal combustion system, said cylinder head mounted to said cylinder block.

Description of the prior art

In heavy duty vehicles, especially vehicles having an internal combustion engine a conventional way of providing lubricant to selective engine components is via an oil/lubricant gallery, which is pressurized. The lubricant is pumped into the pressurized gallery via a lubricant conditioner, which may include an oil filter module, which conditions the oil, e.g. filters it and may heat/cool it additionally. Most of the engine systems are supplied with lubricant from a main lubricant gallery directly downstream of an oil cooler (and oil cooler bypass, if the cooler is closed or partly open).

The lubricant gallery is fluidly connected to selective engine parts to be lubricated via a manifold or like. An example of selective engine parts is the crank train, which is a general term for moving parts related to the crankshaft. Such moving parts include the crankshaft bearings, but may also include other moving parts to be lubricated that form part of a crank system. Another example of selective engine parts is the valve train, which is a general term for moving parts associated with cylinder valve actuation, used for controlling opening and timing of gas inlet and exhaust valves.

Cylinder valve actuation may be provided by many actuator systems that are closely coupled to the cylinder timing, which is in turn closely coupled to the crankshaft rotation, and may include camshaft and/or valve mechanisms or other (electronic) actuator systems that control the valve timing. Lubricant is typically provided from a lubricant collection chamber or sump; the lubricant pump has a pump inlet fluidly coupled to the sump; and a pump outlet fluidly coupled to a lubricant filter module. The filter module is located between the pump outlet and lubricant gallery that fluidly connects to selective engine components to be lubricated. Typically the engine internal lubrication system is downstream of the lubricant heat exchanger (oil cooler), which means that the approximately same oil temperature will be offered to all components and systems of the engine.

One of the challenges is that lubricant becomes less viscous with increased temperatures, and specific engine parts and or systems have different lubrication requirements, e.g. some parts and or systems that accept or need more viscous behaviour and other parts or systems that require less viscous behaviour of the lubricant. The invention aims to provide an internal combustion system comprising a lubrication circuit that accommodates lubrication in various viscosity regimes.

Summary of the invention

In one aspect, it is aimed to provide an internal combustion system comprising a lubrication circuit according to the features of claim 1.

In another aspect, the lubrication system according to the present invention is characterized by an internal combustion system comprising a lubrication circuit in fluid communication with a lubricant pump and at least one lubricant conditioner and provided for lubrication of a crank train in a cylinder block of said internal combustion system, and for lubrication of a valve train in a cylinder head of said internal combustion system. The lubrication circuit comprises at least one supply channel in said cylinder block coupling said lubricant pump to a first lubricant gallery in said cylinder block that provides lubricant towards said crank train. The supply channel is fluidly coupled to a continued supply channel provided in said cylinder head that connects to a second gallery that provides lubricant towards the valve train.

Specifically, said supply channel and/or said continued supply channel traverses a coolant duct that is in thermal contact with said supply channel and/or continued supply channel, in order to provide a reduced lubricant temperature to said valve train. In this way, for the cylinder head a different (lower) temperature regime can be provided than for the cylinder block which is more favourable for the valve train. More specifically, while in the crank train a typically less viscous oil is beneficial to reduce friction losses, in the valve train, such less viscous oil may induce wear which may be prevented. In practice a reduction of lubricant temperature of more than 5 degrees or even 10 degrees Celsius can be attained. This obviates a necessity for separate tailored system with different design characteristics each with a separate oil conditioning systems and separate lubricant circuits provided in different temperature and/or viscosity regimes. In this design a single oil conditioner/cooler can be used while at the same time multiple temperature regimes can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further elucidated in the figures:

Figure 1 shows a schematic front view of an internal combustion system comprising a lubrication circuit;

Figure 2 shows a schematic side view of the internal combustion system of Figure 1;

Figures 3a-c show schematic embodiments of a cooling interface provided between a lubricant supply channel and a coolant duct.

DETAILED DESCRIPTION

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs as read in the context of the description and drawings. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In some instances, detailed descriptions of well-known devices and methods may be omitted so as not to obscure the description of the present systems and methods.

Terminology used for describing particular embodiments is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "and/or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises" and/or "comprising" specify the presence of stated features but do not preclude the presence or addition of one or more other features.

While example embodiments are shown for systems and methods, also alternative ways may be envisaged by those skilled in the art having the benefit of the present disclosure for achieving a similar function and result. E.g. some components may be combined or split up into one or more alternative components. Finally, these embodiments are intended to be merely illustrative of the present system and should not be construed as limiting the appended claims to any particular embodiment or group of 5 embodiments. Thus, while the present system has been described in particular detail with reference to specific exemplary embodiments thereof, it should also be appreciated that numerous modifications and alternative embodiments may be devised by those having ordinary skill in the art without departing from the scope of the present systems as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

Any reference signs in the claims do not limit their scope; several "means" may be represented by the same or different item(s) or implemented structure or function; any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

According to the invention oil supply channel is designed to not only connect oil galleries for crank train and valve trains, as part of an oil supply system but in addition to function as an oil cooler traversing a coolant duct section that is in thermal contact with the supply channel in order to provide a reduced lubricant temperature to said valve train.

Thus oil in the supply channel is intentionally cooled while passing through the duct section which lowers the temperature supplied to the cylinder head and other components and systems fitted in and on it, downstream of the oil supply channel.

This idea enables the engine to operate with different oil system temperatures up- and downstream of the oil supply channel. E.g. by adjusting the heat exchange area of the oil channel cooling wall between the oil supply channel and cooling channels cooling performance can be optimized.

To manufacture the coolant duct section and a traversing oil supply channel, oil supply channel can be drilled in the same (casting) material as the cylinder block and cylinder head as a parent bore but for improved heat exchange an additional connection interface, e.g. a pipe with different material of higher thermal conductivity can be inserted as oil channel cooling wall. Additional features like ribbing and turbulators for increased heat exchange area and improved efficiency could be added to the design of the oil channel cooling wall as well, either as integral part of the structure of the cylinder block and / or cylinder head or as separate part.

Figure 1 shows a schematic perspective front view of an internal combustion system 100 comprising a lubrication circuit. Internal combustion system 100 comprises a lubrication circuit 14, 3, 5 in fluid communication with a lubricant pump 15 and a lubricant conditioner (not shown). The lubrication circuit is fluidly connected to lubricant gallery 3a in cylinder block 1 which extends along the crank tram 9 (represented by crankshaft centerline) towards multiple crankshaft main bearings 7 via oil supply drillings 6a of a crankshaft provided for lubrication of a crank train 9 in cylinder block 1 of said internal combustion system 100. In particular, the crank train 9 may comprise multiple crankshaft main bearings 7 and other bearings and or moving parts to be lubricated.

The lubrication circuit further connects to a second lubricant gallery 3b which extends along the valve train 10 (represented by camshaft centerline) towards multiple valve train bearings 8 via oil supply drillings 6b. In this embodiment, valve train 10 comprises a camshaft and second lubricant gallery 3b is for lubrication of the valve train in cylinder head 2 of said internal combustion system 100, which 1s mounted to said cylinder block 1.

A supply channel 14 extends in said cylinder block from the lubricant pump 15 to first lubricant gallery 3a in said cylinder block 1 that provides lubricant towards said crank tram 9. The supply channel continues in a supply channel 5a, fluidly coupled to a continued supply channel 5b provided in said cylinder head 2 that connects to second gallery 3b that provides lubricant towards the valve train 10. In particular, the valve train may comprise multiple camshaft bearings 8 and/or valve actuators to be lubricated.

Continuing describing the layout of the engine of Figure 1, cooling ducts 4a and 4b are provided that extend in the cylinder block and cylinder head respectively. The cooling ducts may be conventionally designed and will not be elaborated in detail for their specific cooling function, in particular for cooling the cylinder jacket and cylinder head(s). Main aspect of this disclosure 1s that supply channel 5a and/or said continued supply channel 5b traverses a coolant duct 4a and/or 4b. By traversing the coolant duct 4a and/or 4b thermal contact is established with lubricant in supply channel 5a in cylinder block 1 and/or cylinder head 2 , in order to provide a reduced lubricant temperature by heat transfer to the coolant. Since the lubricant flow is from the cylinder block 1 to cylinder head 2, the lubricant temperature in the cylinder head may be reduced so that the valve train can be provided with a lubricant of different conditioning than the lubricant flowing in part of the cylinder block 1.

Figure 2 shows a schematic side view of the internal combustion system of Figure 1, where it can be seen that supply channel 14 rises upwards to a first lubricant gallery 3a in connection with crank train 9 via lubricant supply channel 6a to main bearings 7 . In particular, lubricant gallery 3a extends along the crank train 9 towards multiple crankshaft main bearings 7. Further, supply channel 14 substantially traverses said first gallery 3a in said cylinder block 1 alongside cylinders 11 and towards said cylinder head 2. Supply channel 14 continues to supply channel 5a that traverses the length of cylinders 11, enclosed in coolant jackets 12. Although the direction of flow is generally upward, there is no particular requirement for carrying out the invention, as long as the supply duct 5a, traverses a coolant duct 4a, b at some point, either in cylinder block 1 or cylinder head 2. A cylinder head coolant jacket 13 may be in fluid contact with coolant duct 4b that traverses supply channel 5a. Here, traverse is to be understood that the supply channel traverses a coolant duct section where thermal contact is exchanged through the supply channel wall 5b, while it is not necessary that the supply channel traverses the coolant duct at all times. To the contrary to further improve thermal contact, in the coolant duct section 4a, 4b, there may be duct arrangements that are in parallel to the supply channel. When exiting the coolant duct section, supply channel is in fluid communication with a gallery. In the shown embodiment, the gallery 3a lubricates the camshaft bearings 8, and/or other valve train components (not shown). In other embodiments, camshaft bearings are not provided in the cylinder head, but the valve train comprises at least a valve actuation mechanism to be lubricated.

While not essential to the invention, also further orientation of the coolant ducts 4a an 4b 1s not essential, but in the disclosed embodiment, coolant duct 4a extends in parallel to said first gallery 3a and coolant duct 4b extends in said cylinder head in parallel to said second gallery 3b which conveniently provides coolant to all cylinders that are aligned along the engine length axis.

Figure 3 shows schematic embodiments of a cooling interface 51 provided between a lubricant supply channel 5 and a coolant duct 4 in a coolant duct section 40, as seen in cross section from above. In embodiment

A supply channel 5 traverses a diameter of said coolant duct 4, so that coolant is in thermal contact along a circumference 51 of the supply channel

5. Alternatively in Figure 3B, supply channel 5 traverses a coolant duct 4 section that 1s in thermal contact with said supply channel 5 via an interface 52. In yet another embodiment supply channel 5 is provided with a modified channel 53 wall that has an enlarged thermal interface with said coolant channel.

Claims

CONCLUSIONS

1. An internal combustion system comprising a lubrication circuit in fluid communication with a lubricant pump and at least one lubricant conditioner and provided for lubricating a crankshaft train in a cylinder block of said internal combustion system, and for lubricating a valve train in a cylinder head of said internal combustion system, said cylinder head being mounted on said cylinder block; — wherein the lubrication circuit comprises at least one feed channel in the cylinder block coupling the lubricant pump to a first lubricant gallery in the cylinder block supplying lubricant to the crankshaft brake; — said feed channel being fluidly coupled to a further feed channel in the cylinder head communicating with a second gallery supplying lubricant to said valve train, — wherein said feed channel and/or said continuous feed channel crosses a portion of a coolant conduit section in thermal contact with said feed channel and/or continuous feed channel, to provide a reduced lubricant temperature to said valve train.

2. The lubrication system of claim 1, wherein the supply channel intersects a diameter of the coolant conduit so that the coolant is in thermal contact along the circumference of the supply channel.

3. The lubrication system of claim 1, wherein the supply channel includes a modified channel wall with an increased thermal interface with the coolant conduit.

4. The lubrication system according to any one of the preceding claims, wherein the coolant line runs parallel to the first gallery.

5. The lubrication system according to any one of the preceding claims, wherein the coolant line extends parallel to the second gallery in the cylinder head.

6. The lubrication system according to any of the preceding claims, wherein the coolant line section is disposed in the cylinder block and is in communication with a cooling water jacket of the cylinder block.

7. The lubrication system according to any one of the preceding claims, wherein the coolant line section is disposed in the cylinder head and is connected to a cooling water jacket of the cylinder head.

8. The lubrication system of any preceding claim, wherein the supply channel extends substantially through the first gallery in the cylinder block, adjacent to a cylinder and toward the cylinder head.

9. The lubrication system of any preceding claim, wherein the first lubricant gallery extends along the crankshaft train to a plurality of crankshaft bearings.

10. The lubrication system of claim 9, wherein the crankshaft train bearings are crankshaft bearings.

11. The lubrication system of any preceding claim, wherein the second lubricant gallery extends along the valve train toward a plurality of valve train bearings.

12. The lubrication system of claim 11, wherein the valve train bearings are camshaft bearings and/or valve actuators.

13. The lubrication system of any preceding claim, wherein the lubricant conditioning module comprises a single lubricant cooler.