FIELD OF INVENTION

This invention relates to a liquid-cooled internal combustion engine and more particularly to an improved cooling arrangement for such engines, which will reduce the likelihood of localized heating in areas those by virtue of their position are devoid of uniform coolant flow, and will promote more uniform cooling throughout the cylinder head of the engine.

BACKGROUND OF INVENTION

The use of liquid cooled internal combustion engines is well known. These engines are formed with cooling jackets in their major components, such as the cylinder block and/or cylinder head, and liquid is circulated through these cooling jackets for cooling the engine. In order to provide a simpler construction, the coolant is delivered into the engine through a main coolant inlet port. The internal portions of the engine are appropriately configured so that the coolant will flow from this inlet to a discharge outlet where it is passed through a radiator for cooling and returned to the engine.

Frequently, the coolant inlet is disposed so that the coolant will flow against a surface of the engine, which forms the combustion chamber. However, by virtue of engine layout, the coolant jacket at the highest point is devoid of uniform coolant flow that results in localized heating of a particular area that is undesirable.

It is, therefore, a principal object of this invention to provide an improved cooling arrangement for a liquid- cooled internal combustion engine wherein the cooling system can be maintained relatively uncomplicated, but wherein localized heating in the said areas is avoided.

SUMMARY OF INVENTION

Present invention deals with a cooling system for an internal combustion engine having a cylinder block with a coolant inlet, a cylinder head with multiple coolant outlets, multiple cooling jackets secured around the cylinder block and the cylinder head such that coolant enter cooling jackets through coolant inlet and exits through coolant outlets. Said cooling system further has a pump placed at coolant inlet such that it facilitates coolant flow inside cooling jackets.

Further, a heat discharging member (hereinafter radiator) is connected to the coolant outlets through a first connecting channel and to the coolant inlet through a second connecting channel. Mentioned cooling system has two types of outlets i.e. a main coolant outlet and a bypass coolant outlet out of which the main coolant outlet has thermostat housing with a thermostat valve for regulating coolant flow to the heat discharging member through the first connecting channel.

The cooling system further has a bypass conduit secured at top position of cooling jackets such that said bypass conduit is connected to bypass coolant outlet on one end and to the first connecting channel on other end in order to facilitate the exit of coolant without intervention of the thermostat housing and the thermostat valve.

Consequently, more uniform flow of coolant is achieved.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 is a left side view of a motorcycle constructed in accordance with an embodiment of the invention.

Figure 2 is an enlarged view of the engine layout in motorcycle of Figure 1.

Figure 3 is a view depicting the essential embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Figure 1 illustrates a two-wheeled motor vehicle, indicated by reference numeral 01, is a step through type two-wheeled motor vehicle mainly composed of a body frame 02, a front fork 08 attached to a head pipe 03 of the body frame 02, a front wheel 07 secured to the front fork 08 and a handle bar 11 further attached to the front fork.

Furthermore, a liquid cooled engine 09 is mounted to a rear portion of the body frame 02, along with the radiator that is positioned above the front wheel at location 04, a rear wheel 06 is secured to the body frame 02 in a vertically swing able manner using a swing arm 05. In addition, rear cushion units 10 suspend a rear end portion of the swing arm 05 from the body frame 02.

Figure 2 illustrate the layout of engine 09 in the vehicle 01, as can be seen the engine is positioned horizontally inclined with reference to the ground.

Figure 3 illustrates the internal combustion engine 09 with the claimed cooling system. Cylinder head jacket 12 and the cylinder block jacket 23 are covering the outer surface of the cylinder head and cylinder block respectively and said jackets 12, 23 are connected to each other in order to facilitate continuous flow of the coolant through many passageways present inside the coolant jackets 12, 23. Mentioned jacket has a coolant inlet 22 on which a pump 24 is connected which is pumping the coolant coming from the heat discharging member/ radiator (not shown in figure) inside the cooling jacket 12,23.

Further, said jacket 12, 23 has two outlets for the coolant exit i.e. main coolant outlet 14 and bypass coolant outlet 17. The main coolant outlet 14 is facilitating the flow of the coolant from the cooling jacket 12, 23 to the radiator through a first connecting channel 16. The flow of the coolant from the cooling jacket 12, 23 is regulated by the thermostat valve 20 secured inside the thermostat casing 18 placed in the main coolant outlet 14. The radiator is further connected to the pump inlet 25 through the second connecting channel 21 in order to facilitate supply of coolant.

The cooling system for the internal combustion engine 09 has a bypass conduit 15 as an essential embodiment of the invention, which is connected to the cooling jacket 12, 23 through the bypass coolant outlet 17 secured on top of the cooling jacket 12, 23. Said bypass conduit is connected to the first connecting member through a provision marked as 13. The bypass conduit 15 is enabling the coolant entrapped at the passageway defined by said coolant jacket 12, 23, that is at the highest point with reference to the ground, flow to the radiator.

The bypass conduit 15 is lesser in cross-section compared to the main coolant outlet 14 of the coolant jacket 12,23 so that the majority of coolant flows through the main coolant outlet 14 of the coolant jacket 12,23 and only the entrapped coolant passes through the bypass conduit 15.

It should be understood that the foregoing description is that of a preferred embodiment of the invention and that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.

While the illustrated vehicle depicts a horizontally inclined engine, certain features, aspects and advantages of the present invention may also find utility with other types of engine orientations.

WHAT IS CLAIMED IS:

1) A cooling system for an internal combustion engine, comprising:

a) a cylinder block having a coolant inlet;

b) a cylinder head having a plurality of coolant outlet;

c) a plurality of cooling jacket secured around the cylinder block and the cylinder head such that coolant enters the plurality of cooling jacket through the coolant inlet and exits through the plurality of coolant outlet;

wherein, the plurality of cooling jacket is defining a plurality of passageway facilitating coolant flow around the cylinder block and the cylinder head;

d) a pump secured at the coolant inlet, configured to facilitate coolant flow inside the plurality of cooling jacket;

e) a heat discharging member connected to the plurality of coolant outlet of the plurality of cooling jacket through a first connecting channel and to the coolant inlet of the plurality of cooling jacket through a second connecting channel;

wherein, the plurality of coolant outlet is comprising a thermostat housing with a thermostat valve configured to regulate coolant flow to the heat discharging member through the first connecting channel; and

f) a bypass conduit secured at top position of the plurality of cooling jacket such that said bypass conduit is connected to the plurality of coolant outlet on one end and to the first connecting channel on other end;

wherein, the bypass conduit is configured to facilitate the exit of coolant without intervention of the thermostat housing and the thermostat valve.

2) The cooling system, as claimed in claim 1, wherein the plurality of coolant outlet further comprising a main coolant outlet and a bypass coolant outlet.

3) The cooling system, as claimed in claim 2, wherein the main coolant outlet has the thermostat housing with the thermostat valve.

4) The cooling system, as claimed in claim 1, wherein the pump is connected to the heat discharging member through the second connecting channel.

5) The cooling system, as claimed in claim 1, wherein the bypass conduit is connected to the bypass coolant on one end and to the first connecting channel on the other end.