FIELD OF INVENTION:
[001] The present subject matter described herein, relates to supply of lubricant to internal combustion engine, and in particularly, to a lubricant supply system having two different oil pumps and oil tanks for reducing frictional losses in internal combustion engine to improve valve train durability, fuel consumption, and engine emission performance.
BACKGROUND AND PRIOR ART:
[002] Fig. 1 illustrates the existing lubrication system for lubricating the internal combustion engine. In existing engine lubrication system/circuit 100, a single lubrication circuit is used for engine lubrication, i.e., cylinder head 101 comprising valve train, VVT Mechanism and cylinder block 102 comprising piston, piston ring, crank train, crankshaft journal. Further, an oil sump 103 is placed at bottom of the system 100. Oil from oil sump/pan 103 is collected by oil pump 104 and pressurized oil is discharged to lubrication circuit through oil filter 105 for valve train lubrication 101 and lubrication circuit takes the oil to valve train system and lubricate the valve train parts, such as cam shaft journal and cam lobe interface via venturi. The oil pump 104 pressurized the oil into the cylinder block 102. Engine crank train operates in hydrodynamic lubrication zone however valve train operates in boundary lubrication zone. To reduce engine friction, engine oil viscosity is reduced to get benefit in hydrodynamic lubrication zone (crank train) however boundary lubrication zone (valve train) gets affected in terms of durability. Therefore, there is a trade off between reduction in hydrodynamic friction and durability of boundary layer lubricated parts. The cylinder head 101 of Valve train parts required high viscosity grade lubrication oil for wear and friction reduction because it operates in boundary lubrication zone. Due to high viscosity oil requirement in the valve train, it is required to supply high viscosity oil to the crank train also which lead to higher friction losses.
[003] This is a technical problem that same grade oil is supplied into both the cylinder head 101 and the cylinder block 102. Due to the same grade oil in both the blocks, the internal combustion engine has several technical problems which are mentioned below:
[004] The existing lubrication system has several losses. High viscosity grade oil is used due to valve train wear constraint which leads to higher engine friction. In order to pump high viscosity grade oil to cylinder head 101, a high capacity oil pump 104 is used for lubricating valve train and crank train. Further, lubrication circuit pressure loss is higher due to long path with inlet pipes 106 and outlet pipe 107 and 108. Due to long lubrication circuit, the VVT response time and lubrication start time lag is higher. Amount of lubrication oil reaching at the cam shaft is limited due to leakage from crank train bearing clearance and long lubrication oil circuit. The Valve train/ crank train lubrication oil temperature cannot be maintained separately as per valve train and crank train temperature requirement (high temperature in cylinder block and low temperature in cylinder head to improve engine performance) by use of separate oil cooling due to single oil circuit. Time lag between the lubrication of cam shaft journal/ cam lobe and starting of engine running due to long lubrication circuit leads to higher wear of valve train components. Quality and quantity of lubrication oil reached to valve train and crank train cannot be optimized accurately for each system as per functional requirement using single (common) crankshaft mounted oil pump.
[005] In the existing system, high capacity oil pump is required to supply lubricant oil into the cylinder head as well as cylinder block. The high capacity oil pump applies pressure on the engine for supplying lubricant oil hence increases fuel consumption.
[006] Accordingly, it is desirable to develop a lubrication system which can be efficiently supplied two different viscosity grade of lubrication oil to the cylinder head and the cylinder block. Therefore, there is a need in the art to provide an lubrication system that can be more simple and inexpensive, and which can be placed in the internal combustion engine of the vehicle without any substantial modification in any other part of the assembly to reduce frictional losses in the internal combustion engine.
SUMMARY OF THE INVENTION:
[007] The subject matter disclosed herein relates to lubricant supply system in the internal combustion engine. The present lubricant supply system has two separate oil pumps and oil sumps (reservoir) for valve train and for crank train separately. In the present lubrication oil supply system, there are two separate circuits one for cylinder head and another for cylinder block for supplying lubrication oil. Both the lubrication circuits have separate oil pump and oil filters. Further, there is no connection between the oil supply circuit of the cylinder block and the cylinder head. The cylinder head lubrication circuit has an oil tank, an oil filter, and an oil pump connected with each other through oil transfer gallery or cavities. The oil pump is connected to the oil tank from one end to suck the lubricant oil type 1 and to the oil filter from other end to filter the lubricant oil type 1. After filtering the lubricant oil type 1, the oil pump supplies the lubricant oil type 1 to a cylinder head oil gallery via the oil transfer gallery. On the other hand, the cylinder block lubrication circuit has an oil pan, an oil filter and an oil pump connected to each other. The oil pump connected with the oil tank from one end and with the oil filter from other end via oil supply gallery. The oil pump supplies lubricant oil type 2 from the oil pan to cylinder block gallery via oil supply gallery. The oil pump is cam shaft driven oil pump which is connected to cam shaft of the internal combustion engine (IC). Accordingly, there is no connection between the oil lubrication system of the cylinder head and the cylinder block, therefore, two different type of lubricant oils with different grade can be supplied to the cylinder head and the cylinder block. By supplying the required grade lubricant oil, there is less wear and tear in the system and fuel consumption also increased due to power management of the oil pump.
[008] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[009] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0010] Fig. 1 illustrate existing lubrication circuit and system for supplying the lubricant to the internal combustion engine; and
[0011] Fig. 2 illustrates lubrication circuit and system for supplying the lubricant to the internal combustion engine, in accordance with an embodiment of the present subject matter.
[0012] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0013] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0014] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0015] Fig. 2 illustrates lubrication circuit and system for supplying the lubricant to the internal combustion engine, in accordance with an embodiment of the present subject matter. In the cylinder head, high viscosity grade oil is used due to valve train wear constraint lead to higher engine friction. If low viscosity grade oil is used, it will lead to wear of valve train parts due to boundary lubrication.
[0016] In the process of developing the present invention, the inventors find at least the following problems: Low efficiency of lubrication system due to long lubrication circuit in existing system so length of oil circuit has to be reduced to minimize pressure losses. Size reduction of main oil pump of engine is not possible due to valve train requirement. Optimization of lubrication oil grade for crank train mechanism is not possible lead to friction loss penalty. Time lag of valve train parts lubrication lead to initial wear of valve train parts.
[0017] The present lubricant oil supply system 100 for internal combustion engine is structured to reduce frictional losses of IC engine. The present oil supply system 100 has separate lubrication circuitry for cylinder head and cylinder block. The cylinder head lubrication circuit 201 has an oil tank 201b, an oil filter 208, and an oil pump 207. The oil pump 207 is connected with each other through oil transfer gallery or cavities 209. The oil pump 207 is connected to the oil tank 201b from one end to suck the lubricant oil type 1 and to the oil filter 208 from other end to filter the lubricant oil type 1. After filtering the lubricant oil type 1, the oil pump 207 supplies the lubricant oil type 1 to cylinder head oil gallery 201a via the oil transfer gallery 209. The cylinder head oil gallery 201a supplies the lubricant oil to valve train, VVT mechanism and HLA mechanism. The oil pump 207 is cam shaft driven pump. The oil pump 207 receives power from the camshaft to supply the lubricant oil type 1. The oil pump 207 can be an electric oil pump to remove load on the IC engine. The cylinder head is modified to have an oil tank 201b which is inclined towards the opening of oil pump 207 so that all drained oil goes back to the oil pump 207 for recirculation. Accordingly, some changes have been made in the cylinder head to store the lubricant oil type 1. After supplying, the lubricant oil type 1 to the valve train, VVT mechanism, and HLA mechanism the lubricant oil type 1 drain towards the oil pump 207. The cylinder head has an oil cooler for cooling the temperature of the lubricant oil type 2.
[0018] On the other hand, the cylinder block lubrication circuit 202 has an oil pan 203, an oil filter 205 and an oil pump 204 connected to each other. The oil pump 204 is connected with the oil tank/pan 203 from one end and with the oil filter 204 from other end via oil supply gallery. The oil pump 204 supplies lubricant oil type 2 from the oil pan 203 to cylinder block oil gallery 202a via oil supply gallery 205a. The oil pump 204 supplies the oil to the oil filter 204 for filtration. After filtration, the lubricant oil type 2 is supplied to the cylinder block oil gallery 202a for lubricating the piston, piston ring, crankshaft journal. The oil pump 204 is crank shaft driven oil pump which is connected to crank shaft of the internal combustion engine (IC). The oil pump 204 can be electric oil pump. Further, capacity of the oil pump 204 depends on the viscosity of lubricant oil type 2 and area of supply. After supplying the lubricant oil type 2 to the cylinder block oil gallery 202a, the lubricant oil type 2 drains in the oil pan 203 via oil return gallery 206 for recirculation. Further, temperature of the lubricant oil type 2 is maintained by separate heat exchanger for oil cooling. The cylinder block has an oil cooler for cooling the temperature of the lubricant oil type 2.
[0019] The lubrication oil temperature of the cylinder head and the cylinder block can be maintained accurately as per valve train and crank train temperature requirements with the help of separate oil cooler for both lubricating circuits. This helps to maintain high temperature in cylinder block and low temperature in cylinder head to improve engine performance by way of optimized friction.
[0020] Accordingly, there is no connection between the oil lubrication system of the cylinder head and the cylinder block, therefore, two different types of lubricant oils with different grade can be supplied to the cylinder head and the cylinder block. By supplying the required grade lubricant oil, there is less wear and tear in the system and fuel consumption also reduced due to better energy management of the oil pump due to its reduced sizing.
[0021] In the present system, two different types of oil grades are used for lubrication of engine power train. Optimization of lubrication oil grade for valve train and crank train mechanism can be carried out separately. Efficiency improvement of lubrication system by reducing the lubrication circuit length /pressure loss of circuit and dividing it in two parts (Cylinder head and cylinder block). The use of Lubrication oil pump on cam shaft (Front side or back side) for lubricating cam shaft journal and cam lobe interfaces. G Rotor type oil pump (Gear type or any other type is also possible) fitted on cam shaft for valve train lubrication. Size reduction of main oil pump of engine, oil sump and oil filter and use of auxiliary cam shaft driven oil pump for valve train parts lubrication. Further use of separate oil cooler for both lubricating circuit to control different oil temperature of cylinder head and cylinder block.
[0022] In the present lubrication oil system, lubrication oil gallery from cylinder block to cylinder head is removed. Main oil pump, oil sump, and oil filter size is reduced to meet crank train requirements only. G rotor type/Gear type oil pump is fitted on cam shaft to lubricate cam shaft journal and cam lobe interface. An electric oil pump can also be used in place of mechanical pump. Separate (oil cooler) is fitted for crank train and valve train for separate oil temperature control of lubrication circuit. Size and capacity of both oil pumps is controlled as per requirement of each system.
[0023] Main gallery (Crank train journal) lubrication oil is supplied by Main oil pump through main oil filter and cooling of lubrication is done by main oilcooler or heat exchanger. Lubrication of cylinder head parts (Valve train) is done by cam shaft driven oil pump using separate oil strainer/ filter and oil cooler for lubrication. Different oil grade is used for both crank train and valve train lubrication circuit. Lubrication oil temperature, quantity and pressure is controlled separately for both the lubrication circuit to improve engine performance.
[0024] The present lubrication oil system is about:
[0025] Design of lubrication circuit for frictional losses reduction of IC engine.
[0026] Use of two different oil grades for lubrication of engine crank train and valve train system, respectively.
[0027] Efficiency improvement of lubrication system by changing the lubrication circuit and dividing it in two parts.
[0028] Use of Lubrication oil pump on cam shaft for lubricating valve train system.
[0029] Size reduction of main oil pump of engine and use of auxiliary oil pump for valve train parts lubrication.
[0030] Optimization of lubrication oil grade for valve train and crank train mechanism since lubrication requirement are different for both systems.
[0031] G rotor type oil pump fitted on cam shaft for valve train lubrication.
[0032] Time lag of valve train lubrication is improved since oil pump is much closer especially in cold condition and high viscosity oil.
[0033] Quality and quantity of lubrication oil reached to valve train and crank train can be optimized separately for each system as per requirement.
[0034] Uses of separate oil pump leads to reduction of main oil pump/ oil filter size and cost.
[0035] In case of hydraulic actuated VVT, response time is improved significantly.
[0036] If HLA is used in valve train then cam mounted oil pump improves the HLA performance also by reducing the time lag between engine starting and building up of oil pressure for proper functioning of HLA.
[0037] The present system also improves the aeration performance of oil because main contributor of oil aeration is oil pan and blow by gases. Improved aeration performance is better for HLA functioning and durability performance of valve train parts.
[0038] Because the valve train lubricating oil is not be in direct contact with blow by gases therefore the contamination and oxidation performance of oil improves leading to longer oil change intervals for valve train lubricating oil as compared to crank train oil.
[0039] Because valve train oil is different therefore crank train oil quantity can be reduced and oil pan size can be optimized. Reduced crank train oil which needs frequent change intervals directly reduces the service cost impact to customer.
[0040] Simplification of cylinder block, cylinder head and gasket cylinder head design due to elimination of blow by and oil return galleries. The present system directs impact on weight and cost reduction.
[0041] Frictional power losses improvement of engine by changing the lubrication circuit and dividing it in two parts. Size and cost reduction of main oil pump, oil sump, oil filter of engine and use of auxiliary oil pump for valve train parts lubrication. Time lag of valve train parts lubrication is improved. Valve train/ crank train lubrication oil temperature can be maintained accurately as per valve train and crank train temperature requirement accurately due to the used of separate oil cooler for both lubricating circuit.
[0042] Quality and quantity of lubrication oil reached to valve train and crank train can be optimized separately for each system as per requirement. Use of separate oil circuit lead lubricating oil temperature controlled separately for cylinder head and cylinder block which help to maintain high temperature in cylinder block and low temperature in cylinder head to improve engine performance. Eliminates need of oil metering venturi.
[0043] Improve hydraulic actuated VVT response time. Improvement in oil aeration for valve train to improve performance of HLA. Reduction in oil quantity of crank train which will reduce the service cost for customer. Simplification of cylinder block, cylinder head & gasket cylinder head design due to elimination of blow by and oil return galleries. This will have direct impact on weight and cost reduction. Longer life of valve train lubricating oil due to no direct contact with blow by gases.
[0044] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:
1. A lubrication oil supply system (200) for an internal combustion engine for supplying lubrication oil to cylinder head and the cylinder block, the lubrication oil supply system (200) comprising:
a cylinder head lubrication circuit (201) comprising:
an oil tank (201b) and a oil filter (208);
a oil pump (207) connected with the oil tank (201b) from one end and the oil filter (208) from other end, wherein the oil pump (207) supplies lubricant oil type 1 from the oil tank (201a) to a cylinder head oil gallery (201a) via oil transfer gallery (209); and
a cylinder block lubrication circuit (202) comprising:
an oil pan (203) and oil filter (205);
an oil pump (204) connected with the oil tank (203) from one end and with the oil filter (205) from other end via oil supply gallery, wherein the oil pump (204) supplies lubricant oil type 2 from the oil pan (203) to cylinder block gallery (202a) via oil supply gallery (205a), wherein the oil pump (204) is crank shaft driven oil pump which is connected to crank shaft of the internal combustion engine (IC).
2. The lubrication oil supply system (200) as claimed in claim 1, wherein the oil pump (207) of the cylinder head lubrication circuit (201) is cam shaft driven.
3. The lubrication oil supply system (200) as claimed in claim 1, wherein the oil pump (207) and the oil pump (204) is electric oil pump.
4. The lubrication oil supply system (200) as claimed in claim 1, wherein capacity of the oil pump (204) is higher than capacity of the oil pump (207).
5. The lubrication oil supply system (200) as claimed in claim 1, wherein viscosity of the lubricant oil type 1 in the cylinder head lubrication circuit (201) is higher than viscosity of the lubricant oil type 2 in the cylinder block lubrication circuit (202).
6. The lubrication oil supply system (200) as claimed in claim 1, wherein the cylinder head oil gallery (201a) supplies the lubricant oil to valve train, VVT mechanism and HLA mechanism.
7. The lubrication oil supply system (200) as claimed in claim 1, wherein the cylinder block gallery (202a) supplies the lubricant oil to piston, piston ring, and crank shaft journal.
8. The lubrication oil supply system (200) as claimed in claim 1, wherein the cylinder head is modified to have a cavity to store the lubricant oil type 1, wherein the cavity is inclined towards the opening of oil pump (207).
9. The lubrication oil supply system (200) as claimed in claim 1, wherein the oil filter (208) filters the lubricant oil type 1 received from the oil pump (207) and supplies the lubricant oil type 1 to the cylinder head oil gallery (201a).
10. The lubrication oil supply system (200) as claimed in claim 1, wherein the oil filter (205) filters the lubricant oil type 2 received from the oil pump (204) and supplies the lubricant oil type 2 to the cylinder block oil gallery (202a).
Dated this 1st day of March, 2018