Claims:WE CLAIM:
1. An internal combustion engine (100) for a motor vehicle (10), comprising:
a cylinder block (110), the cylinder block (110) having one or more liners (112) through which a cooling fluid can flow;
a cylinder head (120) provided on the cylinder block (110);
a cooling fluid inlet (130) for allowing entry of the cooling fluid in the internal combustion engine (100), the cooling fluid inlet (130) being provided on the cylinder head (120);
a cooling fluid outlet (140) in fluid communication with the cooling fluid inlet (130), the cooling fluid outlet (140) being provided on the cylinder head (120);
a gasket (150) provided between the cylinder block (110) and the cylinder head (120), the gasket (150) having a primary duct (152) for allowing the cooling fluid to pass from the cylinder head (120) to the cylinder block (110); and
a plurality of auxiliary ducts (154) provided on the gasket (150), the plurality of auxiliary ducts (154) being provided on top of the one or more liners (112), such that cooling fluid can pass from the one or more liners (112) on the cylinder block (110) to the cylinder head (120) through the auxiliary ducts (154).

2. The internal combustion engine (100) as claimed in claim 1, wherein the one or more liners (112) are provided on the cylinder block (110) such that a liner (112) extends across the circumference of a cylinder in an engine top view.

3. The internal combustion engine (100) as claimed in claim 1, wherein the plurality of auxiliary ducts (154) is provided in a distributed manner across the periphery of the gasket (150).

4. The internal combustion engine (100) as claimed in claim 1, wherein the cylinder block (110) comprises a first coolant passage (114) that receives the cooling fluid from the cooling fluid inlet (130), such that the cooling fluid absorbs heat from the cylinder block (110) as the cooling fluid travels along the first coolant passage (114).

5. The internal combustion engine (100) as claimed in claim 4, wherein the cylinder head (120) comprises a second coolant passage (124) that receives cooling fluid from the first coolant passage (114), such that the cooling fluid absorbs heat from the cylinder head (120) as the cooling fluid travels along the second coolant passage (124), and exits the cylinder head (120) from the cooling fluid outlet (140).

, Description:FIELD OF THE INVENTION
[001] The present invention relates to an internal combustion engine for a motor vehicle.

BACKGROUND OF THE INVENTION
[002] Conventional motor vehicles, especially saddle type vehicles with liquid cooled engines, are limited by a large number of challenges. The liquid cooled engines have a pump, a radiator and a set of tubes that connect the pump and the radiator to carry coolant in and out of engine. In that, a liquid-cooled engine with cylinder block and cylinder head have interconnected coolant channels running through them. At the top of the cylinder head all the channels converge to a single outlet. Such conventional liquid cooled engines are highly prone to leaks. Further, these engines are less durable if not maintained well because these engines involve complex passages and pathways to cool various regions of the engine effectively.
[003] Typically, these internal combustion engines are provided with a coolant inlet in one side face of a cylinder block and a coolant in a side face of a cylinder head on the side opposite to the coolant inlet. In such arrangements, cooling is only effective when the coolant inlet and coolant outlet are connected via substantially straight or L shaped connection paths. Any deviation from these configurations of the connection paths leads to inefficient coolant flow from the coolant inlet to the coolant outlet, thereby reducing the efficiency of the cooling mechanism, and thereby the engine performance and life.
[004] Further, provision of coolant inlets and outlets on the side of the cylinder block and cylinder head have an inferior cooling effect as compared to provision of inlets and outlets on the central portion of the cylinder block and cylinder head. In addition, since the coolant inlets and outlets are generally provided on the opposing sides on the cylinder block and cylinder head, effecting the layout of piping for the coolant remains difficult. Such layouts are also limited by the number of communication ducts that can be provided between the cylinder head and the cylinder block, thus further hampering cooling efficiency.
[005] Thus, there is a need in the art for an internal combustion engine for a motor vehicle which addresses the aforementioned problems.

SUMMARY OF THE INVENTION
[006] In an aspect, the present invention is directed towards an internal combustion engine for a motor vehicle. The vehicle has a cylinder block and the cylinder block has one or more liners through which a cooling fluid can flow. A cylinder head is provided on the cylinder block. A cooling fluid inlet is provided for allowing entry of the cooling fluid in the internal combustion engine. The cooling fluid inlet is provided on the cylinder head. A cooling fluid outlet is provided on the cylinder head, in fluid communication with the cooling fluid inlet. A gasket is provided between the cylinder block and the cylinder head. The gasket has a primary duct for allowing the cooling fluid to pass from the cylinder head to the cylinder block. Further, a plurality of auxiliary ducts are provided on the gasket, on top of the one or more liners, such that cooling fluid can pass from the one or more liners on the cylinder block to the cylinder head through the auxiliary ducts.
[007] In an embodiment of the invention, the one or more liners are provided on the cylinder block such that a liner extends across the circumference of a cylinder in an engine top view.
[008] In another embodiment of the invention, the plurality of auxiliary ducts is provided in a distributed manner across the periphery of the gasket.
[009] In a further embodiment of the invention, the cylinder block has a first coolant passage that receives the cooling fluid from the cooling fluid inlet, such that the cooling fluid absorbs heat from the cylinder block as the cooling fluid travels along the first coolant passage.
[010] In a further embodiment of the invention, the cylinder head has a second coolant passage that receives cooling fluid from the first coolant passage, such that the cooling fluid absorbs heat from the cylinder head as the cooling fluid travels along the second coolant passage, and exits the cylinder head from the cooling fluid outlet.

BRIEF DESCRIPTION OF THE DRAWINGS
[011] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a left side view of an exemplary saddle type vehicle in accordance with an embodiment of the invention.
Figure 2 illustrates an exploded view of an internal combustion engine, in accordance with an embodiment of the invention.
Figure 3 illustrates a top view of a cylinder block of the internal combustion engine, in accordance with an embodiment of the invention.
Figure 4 illustrates a top view of a gasket of the internal combustion engine, in accordance with an embodiment of the invention.
Figure 5 illustrates a sectional view of a cylinder head of the internal combustion engine, in accordance with an embodiment of the invention.
Figure 6 illustrates a sectional view of the internal combustion engine, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[012] The present invention relates to an internal combustion engine for a motor vehicle. More particularly, the present invention relates to an internal combustion engine for a saddle type vehicle.
[013] Figure 1 illustrates an exemplary saddle type motor vehicle 10, in accordance with an embodiment of the invention. The saddle type vehicle 10 comprises an internal combustion engine 100 that is vertically disposed. In an embodiment, the IC engine 100 is a single-cylinder type IC engine. The saddle type vehicle 10 further comprises a front wheel 14, a rear wheel 16, a frame member (not shown), a seat 18 and a fuel tank 20. The frame member includes a head pipe 22, a main frame, rear down tubes, and seat rails (not shown). The head pipe 22 supports a steering shaft (not shown) and two telescopic front suspensions 26 (only one shown) attached to the steering shaft through a lower bracket (not shown). The two telescopic front suspensions 26 support the front wheel 14. The upper portion of the front wheel 14 is covered by a front fender 28 mounted to the lower portion of the telescopic front suspension 26 at the end of the steering shaft. A handlebar 30 is fixed to upper bracket not shown and can rotate to both sides. A head light 32, a visor guard (not shown) and instrument cluster (not shown) is arranged on an upper portion of the head pipe 22. The frame member comprises a down tube 44 that may be located in front of the IC engine 100 and extends slantingly downward from head pipe 22. The main frame of the frame member is located above the IC engine 100 and extends rearward from head pipe 22. The IC engine 100 is mounted at the front to the down tube 44 and a rear of the IC engine 100 is mounted at the rear portion of the main frame. In an embodiment, the IC engine 100 is mounted vertically, with a cylinder block extending vertically above a crankcase (not shown). In an alternative embodiment, the IC engine 100 is mounted horizontally with the cylinder block extending horizontally forwardly from the crankcase. In an embodiment, the cylinder block is disposed rearwardly of the down tube 44.
[014] The fuel tank 20 is mounted on the horizontal portion of the main frame. Seat rails are joined to main frame and extend rearward to support the seat 18. A rear swing arm 34 is connected to the frame member to swing vertically, and a rear wheel 16 is connected to rear end of the rear swing arm 34. Generally, the rear swing arm 34 is supported by a mono rear suspension 36 or through two suspensions 36 on either side of the saddle type vehicle 10 (as illustrated in the present embodiment). A taillight unit 33 is disposed at the end of the saddle type vehicle 10 and at the rear of the seat 18. A grab rail 37 is also provided on the rear of the seat rails. The rear wheel 16 arranged below seat 18 rotates by the driving force of the IC engine 100 transmitted through a chain drive (not shown) from the IC engine 100. A rear fender 38 is disposed above the rear wheel 16.
[015] Further, an exhaust pipe (not shown) of the vehicle 10 extends vertically downward from the IC engine 100 up to a point and then extends below the IC engine 100, longitudinally along the vehicle length before terminating in a muffler (not shown). The muffler is typically disposed adjoining the rear wheel 16.
[016] Figure 2 illustrates an exploded view of the internal combustion engine 100, in accordance with an embodiment of the invention. As illustrated, the internal combustion engine 100 comprises a cylinder block 110. The cylinder block 110 is provided with one or more liners 112 through which a cooling fluid can flow. Further, the engine 100 has a cylinder head 120 that is provided on the cylinder block 110. The engine 100 further has a cooling fluid inlet 130 for allowing entry of the cooling fluid in the internal combustion engine 100. Specifically, the cooling fluid inlet 130 is provided on the cylinder head 120. The engine 100 further has a cooling fluid outlet 140 that is in fluid communication with the cooling fluid inlet 130. Specifically, the cooling fluid outlet 140 is provided on the cylinder head 120.
[017] As further illustrated in Figure 2, the engine 100 has a gasket 150 that is provided between the cylinder block 110 and the cylinder head 120. The gasket 150 is provided for sealing the cylinder block 110 from the cylinder head 120, thereby maintaining consistent pressure inside the cylinder block 110. The gasket 150 has a primary duct 152 for allowing the cooling fluid to pass from the cylinder head 120 to the cylinder block 110. The path of the cooling fluid is illustrated by means of arrows in Figure 2, wherein the cooling fluid, supplied by a pump (not shown), enters the engine 100 via the cooling fluid inlet 130 on the cylinder head 120, and thereafter enters the cylinder block 110 by means of the primary duct 152 provided on the gasket 150.
[018] In Figure 3, the entry of the cooling fluid in the cylinder block 110 has been denoted by a cross (X), and the path of the cooling fluid has been denoted by solid arrows. As provided in Figure 3, in an embodiment, the one or more liners 112 are provided on the cylinder block 110 such that a liner 112 extends across the circumference of a cylinder in an engine top view. In an instance, wherein the engine 100 is a multi cylinder engine, the number of liners 112 would equal the number of cylinders in the engine 100.
[019] As referenced in Figure 6, once the cooling fluid enters the cylinder block 110, the cooling fluid flows along the liners 112 provided in the cylinder block 110. The cylinder block 110 is provided with a first coolant passage 114 that receives the cooling fluid from the cooling fluid inlet 130, such that the cooling fluid absorbs heat from the cylinder block 110 as the cooling fluid travels along the first coolant passage 114. As the cooling fluid flows along the liners 112 and the first coolant passage 114 on the cylinder block 110, the cooling fluid absorbs the heat from the circumference of the cylinder and other parts of the cylinder block 110, thereby regulating the temperature of the cylinder block 110.
[020] As the cooling fluid absorbs heat in the liners 112 and the first coolant passage 114, the temperature of the cooling fluid itself is raised and thus, the cooling fluid tends to rise in the liners 112. To facilitate flow of this rising cooling fluid, as illustrated in Figure 4, the engine 100 has a plurality of auxiliary ducts 154 provided on the gasket 150. The plurality of auxiliary ducts 154 are provided on top of the one or more liners 112, such that cooling fluid, as it rises in the liners 112, can pass from the one or more liners 112 on the cylinder block 110 to the cylinder head 120 through the auxiliary ducts 154.
[021] As further illustrated in Figure 4, the plurality of auxiliary ducts 154 are provided in a distributed manner across the periphery of the gasket 150. The plurality of auxiliary ducts 154 and their distribution in such a manner ensure adequate flow of the cooling fluid through the gasket 150 from the cylinder block 110 to the cylinder head 120, thus ensuring not only efficient cooling of the engine 100 but uniform cooling across the cylinder head 120 and the cylinder block 110.
[022] Once the cooling fluid, on absorbing heat from the cylinder block 110, travels to the cylinder head 120 through the plurality of auxiliary ducts 154 on the gasket 150, as illustrated by dotted arrows in Figure 5, the cooling fluid enters a second coolant passage 124 provided on the cylinder head 120. The second coolant passage 124 thus receives the cooling fluid from the first coolant passage 114. As the cooling fluid travels along the second coolant passage 124, the cooling fluid absorbs heat from the cylinder head 120. The cooling fluid after absorbing heat from the cylinder block 110 and the cylinder head 120, as illustrated in Figure 6, exits the engine 100 via the cooling fluid outlet 140 provided on the cylinder head 120. The cooling fluid is then sent to a radiator (not shown) for heat exchange with the atmosphere, and is then recirculated through the engine 100.
[023] Further, in an embodiment, to further enhance the cooling characteristics of the engine 100, the crankcase is divided into a crankcase left hand side (LH) and a crankcase right hand side (RH), which in effect splits a crankshaft or crank chamber and gearbox in the engine 100. Engine oil then travels separately in the crank chamber and the gearbox and an oil pump is provided for ensuring engine oil flow between the crank chamber and the gearbox. To effectuate this split, the engine 100 has a cast wall that divides the crankcase into LH and RH. Such a split ensures that engine oil drag is substantially reduced in the engine 100, along with reduction in engine oil splatter between the crank chamber and the gearbox.
[024] Advantageously, the present invention provides an internal combustion engine for a motor vehicle, which provides for more efficient flow of cooling fluid within the cylinder block, the cylinder head and between the cylinder block and cylinder head, thus improving cooling characteristics of the engine. Further, provision of both the cooling fluid inlet and the cooling fluid outlet on the cylinder head, as opposed to cylinder block result in a significant decrease in engine weight.
[025] Provision of plurality of auxiliary ducts to facilitate flow of cooling fluid between the cylinder block and the cylinder head also ensure more uniform cooling throughout the cylinder block and the cylinder head, resulting in lower thermal load on engine components. Furthermore, the present invention involves minimal number of joints in the coolant path, thus ensuring minimal wear and tear, and lower susceptibility to leakage.
[026] In addition, the present invention allows for a better engine performance along with improved engine durability. The integration of the present invention in engines also remains easy as coolant path is compact.
[027] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.