Speed sensing of an engine

Field of the invention

The present invention relates to "Speed sensing of an engine" and more particularly to speed sensing of an engine wherein the driven shaft in the engine is the sensing element.

Description of the prior art

It is a well-known concept to employ a toothed wheel or gear having equiangular spaced teeth on the engine crankshaft or camshaft in conjunction with a fixed sensor to provide a pulse train output signal as the toothed wheel rotates. The pulse train signal is used to provide information about the speed of the engine. The timing information that is derived there from is useful in controlling ignition timing as well as timing and fuelling of fuel injection systems inter alia. However, in the above construction, the sensor and the sensing element, both being in proximity of oil in the gear box, were subjected to fluctuations in oil temperature in addition to impurities, difficulty in maintenance, etc.

To avoid the above said problems in the prior art, electronic speed sensors were introduced in the engine sprocket cover. However, separate sensing elements were used along with the driven shaft that leads to cost and maintenance issues.

As a result of the above said lacunae in the prior art, the main objective of the present invention to provide a sensing element without the use a separate part.

Another objective of the present invention is to provide an effective mounting for the speed sensor so that it works in concurrence with the sensing element effectively.

Brief description of the invention

According to one of the embodiments, in the present invention, speed detecting system for an engine comprises an extended driven shaft and an driven sprocket mounted on the said driven shaft, an engine sprocket cover covering the said engine driven sprocket and the said driven shaft, wherein the extended portion of the said driven shaft is the speed sensing element, and a speed sensor is mounted on the said engine sprocket cover by means of a bracket. Moreover, the speed sensor is mounted on the said bracket by means of at least one bracket holding screw.

Brief description of the drawings

Figure 1 illustrates side view of a motorcycle.

Figure 2 illustrates a four stroke internal combustion engine.

Figure 3 illustrates the present invention.

Detailed description of the invention

A selected illustrative embodiment of the present invention will be now described with respect to the accompanying figures 1, 2 and 3.

A motorcycle as illustrated in figure 1 comprises of a frame 101, front fork 102 attached to a pivot tube 103 of the vehicle frame 101, a front wheel 104 attached to these front forks 102, a handle bar 105 connected to the front forks 102, a fuel tank 106 attached so as to straddle an upper part of the vehicle frame 101, a seat 107 attached to the upper rear portion of the vehicle frame 101, an engine unit 200 attached to the lower front section of the vehicle frame 101, a swing arm 109 attached to a lower rear section of the vehicle frame 101, suspended by a rear shock absorber 110 from the vehicle frame 101 and a rear wheel 111 attached to a rear end of swing arm 109. The intake system of the engine (not shown in the figure) comprises of a carburettor, intake duct and an air cleaner. The exhaust system of the "engine (not shown in the figure) comprises of exhaust pipe and a muffler. The motorcycle is also provided with a side cover 112 for covering a side section of the vehicle frame 101, a seat cover (not shown in the figure) for covering a rear section of the vehicle frame 101 below the seat 107, a front fender 113 for covering an upper part of the front wheel 104, and a rear fender 114 for covering an upper part of the rear wheel 111. The core part of the engine 200 as illustrated in figure 2 is the cylinder 201 with the piston 202 moving up and down inside the cylinder 201. Some of the key engine parts along with their functions are spark plug (nor shown in the figure) which supplies the spark which ignites the air/fuel mixture so that combustion could occur; valves 203 wherein the intake and exhaust valves open at the proper time to let in air and fuel to let out exhaust; a piston 202 which is a cylindrical piece of metal that moves up and down inside the cylinder 201; piston rings 204 that provide a sliding seal between the outer edge of the piston 202 and the inner edge of the cylinder 201; connecting rod 205 which connects the piston 202 to the crankshaft 206; crankshaft 206 which turns the piston's up and down motion into circular motion; a sump 207 which surrounds the crankshaft 206 and contains oil which collects in the bottom of the sump 207; etc. The said crankshaft 206 drives a driven shaft 300 through a counter shaft (not shown in figure). The blow by gases from the crankcase 208 (with right 306 and left 307 crankcase halves) is passed through the air filter unit that filters it and adds to the intake gases going into for combustion.

According to one of the embodiments, in the present invention, speed detecting system for engine 200 comprises an extended 'driven shaft 300 and an driven sprocket 301 mounted on the said driven shaft 300, an engine sprocket cover 302 covering the said engine driven sprocket 301 and the said driven shaft 300, wherein the extended portion of the said driven shaft is the speed sensing element, and a speed sensor 303 is mounted on the said engine sprocket cover 302 by means of a bracket 304. Moreover, the speed sensor is mounted on the said bracket by means of at least one bracket holding screw 305.

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. Further any shape and configuration of the extended surface is possible within the ambit of appended claims.

Claims

We claim:

1. A speed detecting system for a motorcycle having a four stroke internal combustion engine with a crankcase with left and right side crankcase halves comprising an extended driven shaft and an driven sprocket mounted on the said driven shaft, an engine sprocket cover covering the said engine driven sprocket and the said driven shaft, wherein the extended portion of the said driven shaft is the speed sensing element, wherein a speed sensor is mounted on the said engine sprocket cover by known mounting means.

2. The speed detecting system as claimed in claim 1, wherein the speed sensor is mounted on the said engine sprocket cover by means of a bracket.

3. The speed detecting system for as claimed in claim 1, wherein the speed sensor is mounted on the said bracket by means of at least one bracket holding screw.

4. The speed detecting system as claimed in claim 1, wherein the system is provided on the left side crankcase half.

5. A motorcycle having the speed detecting system as claimed in clam 1.

6. A speed detecting system for a motorcycle substantially as herein described with reference to, and as illustrated in, the accompanying drawings