Transmission system for an internal combustion engine

Field of the invention

The present invention relates to "Transmission system for an internal combustion engine" and more particularly to torque control mechanism for a single speed transmission system of an internal combustion engine.

Description of the prior art

Normally for a single speed transmission system includes an engine, a centrifugal clutch, a gearbox and a wheel. The transmission system is provided on the left side of the engine. A clutch arrangement is mounted on the crankshaft, which consists of shoes, which are pivoted on a plate, which rotates positively along with the crankshaft. A housing connected to the drive gear is freely mounted on the crankshaft. As the plate is rotated by the crankshaft at a speed more than a pre-determined value, due to centrifugal action, the shoes fly off and catch the housing inner surface and in turn rotate the housing and the gear along the crankshaft axis. The gear in turn drives a driven gear, which is mounted on a shaft in an axis parallel to the crankshaft axis. This shaft is mounted on crankcase L and cover clutch using bearings. On the outer side of the shaft, a drive sprocket is attached using splines. A chain drive is connected between the drive sprocket and driven sprocket.
The driven sprocket is attached on a shaft and which in turn is mounted on the extended portion of the crankcase L and a cover using bearings. On the right side of the shaft, the rear wheel is attached using splines and a central nut.

Normally in this type of arrangement, when a user starts the engine, it takes some time for the centrifugal clutch to get engaged and drive the wheel. This arrangement makes the user feel apparent loss of initial power or thrust momentarily after start of the motorcycle and before movement of the motorcycle. Therefore, the main objective of the present invention is to reduce this transient or momentary power loss felt by the user when the engine is started.

Objective of the invention

Achieving good initial acceleration in a single speed motorcycle without affecting mid-range and maximum speed requirement and improving single speed transmission motorcycle acceleration by assisting with an electric motor that provides additional torque required during initial as well as sudden acceleration.

Brief description of the invention

In the above configuration, the torque transfer from engine to wheel is through a chain drive mechanism. A hub motor is mounted to the rear wheel that rotates with the wheel and assists the engine during initial and also sudden acceleration. As a result of the above configuration in, the user doesn't feel the momentary loss of power to drive the vehicle that is assisted by the said hub motor connected to the drive wheel.

Brief description of the drawings

Figure 1 illustrates side view of a motorcycle having single speed transmission.

Figure 2 illustrates the hub motor arrangement in the present invention.

Figure 3 illustrates flow chart according to the present invention.

Figure 4 illustrates the circuit diagram involved in 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 with a single speed transmission system with a body frame 100 comprises a head pipe 101, at least a tube extending downwardly and then extends almost horizontally (not shown in the figure) and then at the posterior position extends upwards (not shown in the figure) and further backwardly and horizontally. The rear most part of the said tube is opened to the atmosphere. A front wheel 102 is carried through the intermediary of a front fork 103 that is rotatably mounted within the head pipe 101. A rear wheel 104 is carried on the rear end of a rear fork 105 that is swingably pivoted on the rearward lower position of the vehicle body frame 100. A seat 106 is disposed above the shock absorber 105. Forwardly of the seat, a fuel tank 107 is mounted over the mono pipe 101. Behind the fuel tank 107, a step through space 108 is provided between the fuel tank 107 and the seat 106. A four-stroke cycle engine 200 is mounted under a footboard 110 and behind the front wheel 102. The exhaust pipe 111 extends from the engine 109 to the rear portion of the vehicle. The swing arm 113 is not visible in this view.

In the above configuration (figure 2), the torque transfer from engine 200 to rear wheel 104 is through a chain drive mechanism 112. A hub motor 201 is mounted to the rear wheel 104 that rotates with the wheel 104 and assists the engine 200 during initial and also sudden acceleration. The operation of the above said configuration could be observed from the flow chart (figure 3) operation explained below.

Once the vehicle starting system is switched ON (1), there is ignition check (2). If at this moment ignition is switched off, the above system is in cut-off position (7). It the ignition is in ON state, the system goes for throttle position sensor check (4). If the rate of change of throttle position is within predetermined level, the system goes for engine RPM check (5). If the engine RPM is less than the predetermined level, it activates the hub motor for about N seconds (6). After N seconds, the system is disconnected (7) and the hub motor is switched off. In addition to above sensors, a speed check mechanism is also present for determination of vehicle speed to engage or disengage the hub motor. In normal conditions, N varies from 3 to 12 seconds. As a result of the above configuration in, the user doesn't feel the momentary loss of power to drive the vehicle that is assisted by the said hub motor connected to the drive wheel.

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 torque control mechanism for a single speed transmission system in a four stroke internal combustion engine for a motorcycle comprising

a. an ignition check means;

b. a throttle position sensing means;

c. an engine rpm sensing means;

d. a hub motor mounted on rear wheel of the motorcycle;

e. a vehicle speed determining means; and

f. a timer controlled switch.

2. The torque control mechanism as claimed in claim 1, wherein once the motorcycle starting system is switched ON, and the ignition is in ON state, and the rate of change of throttle position is within predetermined level, the system goes for engine RPM check and when the engine RPM is less than the predetermined level, it activates the hub motor for about N seconds.

3. The torque control mechanism as claimed in claim 2, wherein N ranges between 3 to 12 seconds.

4. A torque control mechanism for a single speed transmission system in a four stroke internal combustion engine for a motorcycle comprising a hub motor mounted to the rear wheel that rotates with the wheel and assists the engine during initial and sudden acceleration of the motorcycle.

5. A motorcycle having a torque control mechanism as claimed in claim 1 and claim 4.