|Title of Invention||
AN AUTO DECOMPRESSION ACTUATING MECHANISM FOR IC ENGINES
|Abstract||An auto decompression actuating mechanism for m IC engine comprising a decompression cam mounted on the kick shaft of the engine and driving a rocker lever one end of which is hinged to a bracket mounted on the engine cover; a flexible cable one end of which is connected to the other end of the rocker lever, the cable, at its other end, being connected to the decompression valve provided on the cylinder head of the engine; and a lever for operating the kick shaft Fig. of drawings|
I he present invention relates to" Auto decompression actuating mechanism for IC engines".
Normally IC engines are started by cranking the crankshaft by operating a leg operated or hand operated lever and gear train. Some of the engines are provided with self-starting mechanism by electric motor. In order to reduce cranking effort and to improve the startability, some of the engines are equipped with a hand lever operated decompression valve. Decompression valve which is provided on the cylinder head of the engine, when operated helps to release part of the compressed charge from combustion chamber to outside, reducing the volume of charge to be compressed, lowers the pressure acting on the piston and hence less cranking effort This valve is manually closed at moment of start of the engine. In the case of engines with valves provided in the cylinder head, for example on four stroke engines, the decompression is achieved by pressing exhaust valve for starting. Operating lever is normally mounted at handle bar or front panel of the vehicle.
Operating decompression lever and valve needs precise manual control by the rider. The decompression valve has to be closed immediately when the engine is started. If closing is not done precisely, a large amount of effort and cylinder charge will be wasted. In some of the vehicle we need to operate a choke lever also to give rich air fuel mixture for starting. Operating decompression lever and choke lever simultaneously manually and that too by hand lever/leg lever is a very difficult task.
It is therefore an object of this invention to overcome the above problem by providing a cam-iever-cabte arrangement to precisely open arKi close the decompression valve automatically during the engine cranking.
The invention will now be explained in detail with reference to the following drawing
Fig.1 is a side view of a typical two-stroke engine showing the proposed arrangement
Fig. 1 consists of a typical 2 stroke Engine E consisting of cylinder head 4 provided with Spark plug 1. A Piston 6 is reciprocating inside the Cylinder block 5. A Connecting rod 7
moves the Piston 6 inside the Cylinder block 5. The Engine E is started by any known means of kick starter arrangement through a Kick shaft 10 which is housed in the Engine cover 13. A Lever 12, which can be either hand operated or leg operated operates the Kick shaft 10. A Decompression cam 9 is mounted on the Kick shaft 10 by any known means. The Decompression cam 9 drives a Rocker lever 8, which is hinged at Point P on a Bracket 11, which is mounted on the Engine cover 13.The other end of the Rocker lever 8 is connected to a flexible Cable 2. Another end of the Cable 2 operates the Decompression valve 3 provided on the Cylinder head 4.
The working of the system is as follows;
When the Lever 12 is operated either by hand or by leg. the kick shaft 10 rotates and the Decompression cam 9 mounted on the shaft 10 lifts the Rocker lever 8. The linear travel of the R^yefc;ertevev % puHs theCabte 2. ^(Wch ^?per«ftas the Decompresston valve 3.The amount of lift of cam and cam timing is optimized to give precise opening and closing events for Decompression valve 3. Since this mechanism operates automatically, no manual control is required.
Even, thouph the above explanation is given for a typical two-stroke engine, a similar arrangement for actuating the exhaust valve or decompression valve provided on four-stroke engine for decompression is possible.
l.An auto decompression actuating mechanism for en IC engine comprising a decompression cam mounted on the kicit shaft of tiie engine and driving a rocker lever one end of which is hkged to a bracket mounted on ^e engine cover; a flexible cable one end of which is connected to the other end of the rocker lever, the cable, at its other end, being connected to the decompression valve provided on the oylhider head of the engine; and a lever for operating the kick shaft
2. An auto decompression actuating mechanism forIC engines substantially as herein described with reference to and as illustr^ed in the accompanying drawings
|Indian Patent Application Number||627/CHE/2004|
|PG Journal Number||38/2010|
|Date of Filing||01-Jul-2004|
|Name of Patentee||TVS MOTOR COMPANY LIMITED|
|Applicant Address||"JAYALAKSHMI ESTATES", 8, HADDOWS ROAD, CHENNAI-600 006.|
|PCT International Classification Number||F01L13/08|
|PCT International Application Number||N/A|
|PCT International Filing date|