Safety device for scooter type vehicle

Field of the Invention:

The subject matter described herein, in general, relates to a scooter type vehicle and in particular relates to automatic manual transmission control unit incorporating the safety features.

Background of the Invention:

In a conventional two wheeler, rotation of a crankshaft inside a crankcase cover of an engine is changed by a transmission. In this transmission, a multistage shifting mechanism including a main shaft of a gearbox, a drive shaft, and multistage change gears is housed therein, and a clutch for connecting/disconnecting transmission of rotation when shifting the gears is provided. Moreover, an automatic manual transmission control device for automatically actuating the clutch and shifting the change gears of the transmission, in other words an AMT mechanism is provided.

The AMT mechanism includes a clutch actuator for actuating the clutch, a shift actuator for shifting the change gears of the transmission, and other components necessary for the AMT. This AMT system increases fuel economy apart from driving comfort for the user. In this, individual driving preference are not restricted as rider can decide in which mode he/she wants to run the vehicle.

Moreover, there has been a problem that the AMT mechanism is susceptible to inefficient working during starting and cornering of the vehicle. If during the starting of the vehicle no information whether rider is sitting on the seat or not, is not fed to AMT controller, there will be a danger to the rider standing and starting the vehicle because there will be no restrictions from the AMT controller for shift up instruction.

Similarly, during cornering if no restriction is put on the shift up operation, it can lead to fatal accident. It is also necessary to detect the side stand state whether it has been released or is ON during the starting of the vehicle. Generally most riders have a habit of taking the seat first and then releasing the side stand, in such a case it might happen that the rider forgets to remove side stand and starts the vehicle which can lead to accidents too.

Therefore considering safety as an important factor, the above mentioned problems are answered in the present invention.

Summary of the Invention:

An object of the present invention is to enhance safety and comfort in two wheeler having AMT equipped engine.

Another object of the present invention is to incorporate the safety features in the existing controller for AMT.

Another object of the present invention is to provide evaluation means based on road condition and occupant state.

Yet another object of the present invention is to provide a cost effective means of ensuring extra safety for AMT vehicle.

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 from this detailed description.

Brief Description of the Invention:

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein

Figure 1 shows a conventional scooter type vehicle.

Figure 2 shows scooter type vehicle with the AMT controller according to the present
invention.

Figure 2a shows the AMT controller according to the present invention.

Figure 3 corresponds to the flow chart for AMT controller according to the present
invention.

Figure 4 shows the flowchart for interlock function based seat occupancy sensor
according to the present invention.

Figure 5 shows the flowchart for interlock function based on tilt angle sensor according to the present invention.

Detailed Description of the Invention:

The present invention now will be described more fully hereinafter with different embodiments. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather those embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the invention to those skilled in the art.

With reference to Figure 1,1 denotes a front wheel, 2 denotes a front fork, 3 denotes a front fender, 4 denotes a front cover, 5 denotes a leg shield made of resin or metal, 6 denotes a handle bar cover, 7 denotes a headlight, 8 denotes a handle bar ,17 denotes a rear fender and 18 denotes tail lamp.

The centre of the body forms a low floor board 9 for functioning as a part for putting feet and a under cowl 10 which is located below the rider's seat and covers at least a part of the engine, The under cowl is made up of metal or resin. The under cowl is hinged to the seat 11. A utility box 12 opens from the rear end to hinged portion. The utility box 12 is provided under the seat extending longitudinally of a vehicle body and the inside of the utility box has a large capacity so that a large article can be housed. A main frame 14 extended along the center of the body before and behind and made of a metallic pipe and is provided under the floor board 9. A swing type power unit 13 is coupled to the rear end of the main frame 14.

A rear wheel 15 is supported on one side of the rear end of the swing type power unit 13. The swing type power unit 13 is suspended in the rear of a body frame.

The side covers 16 both on left and right sides, covers the utility box 12 and other parts of the vehicle, thereby providing a good appearance to the vehicle.

According to one embodiment of the present invention and referring to Figure 2, an automatic manual transmission equipped engine 201 is supported by a scooter type body frame and having a clutch actuator configured to actuate clutch and shift actuator configured to shift the change gears. A controller 202 is provided for activating the said shift actuator and the clutch actuator. The said controller 202 for AMT 201 provides operating commands to the clutch and shift actuator considering input or feedback from various sensor signals like engine speed signal, vehicle speed signal, throttle position signal, gear position signal, clutch position signal, knock sensor interface signal, gear up signal, gear down signal, brake switch signal, drive mode signal, sport mode signal, start/stop signal, fuel select switch signal, power supply signal and like signals (shown in Figure 2a).

At most of the riding conditions it becomes desirable to effectively restrict an undesired shift up considering the safety of the rider/occupant.

When cruising is performed at a fixed speed, the gear ratio is set such that the shift up is performed one after another to enable the travelling at the engine rotational speed as low as possible. Due to such setting, when the vehicle arrives at the corner during travelling, unless a state that the vehicle is cornering is detected by certain means, the shift up which brings about the change of the engine rotational speed or engine output is performed in the same manner as the cruising even when the vehicle is cornering whereby the riding feeling is adversely affected.

To cope with such a drawback, a tilt sensor 204 is provided according to the present invention and which provides the vehicle tilt information to the AMT controller 202. The said tilt sensor 204 is mounted horizontally on PCB of the controller 202 which is placed parallel to the road surface. The said sensor 204 keeps sending the tilt angle information to the AMT controller 202. The said AMT controller 202 in turn uses this information (with some other vehicle parameters like throttle opening, engine speed and vehicle speed) to calculate the maximum tilt threshold angle which is allowed to activate the gear shift up operation.

During gearshift operation, the wheel traction force changes due to change of gear ratio for a same engine operating point. The traction force has two components viz horizontal component and vertical component. The vehicle tends to skid laterally due to horizontal component of this traction force. It is very much essential to maintain equilibrium point of the horizontal component of the traction force in the tilt situation for a safe driving.

The information of the tilt sensor 204 works as an interlock for the gearshift operation during the vehicle turning. The interlock does not allow any gear shift if the vehicle reaches maximum tilt threshold angle for that particular operating point.

The said tilt sensor 204 can be bidirectional /single directional, ON/OFF tilt sensor or normally open when placed horizontally. It can function as ON / OFF tilt sensing, normally open when above switch angle, normally closed when below switch angle. Switch angles can be 15 degree, 30 degree, 45 degree or can be customized as per the requirements. The sensor 204 is designed to be non-sensitive to vibration when horizontal.

Similarly during starting of the vehicle unlike in car, in two wheeler vehicle it is not necessary to sit on the seat and start the vehicle. There is a possibility that the driver may start the engine without occupying the seat on a two wheeler vehicle. As the gearshift operation is controlled by the AMT controller 202, the vehicle may start rolling or run away with the opening of throttle in above mentioned situation. This can be a very dangerous situation for both the driver and other road users. This situation can be avoided by monitoring the driver's seat occupancy state. According to the present invention a seat occupancy sensor (or detecting means) 205 is integrated and placed at centre of the rider's seat. The said sensor 205 has two output states viz ON and OFF. The output state depends on the weight on the sensor. If the rider sits on the said sensor 205, the output state changes to ON and vice versa. This output state information of this sensor 205 is used to detect the occupancy status of the rider. This information is fed to the AMT controller 202 for further processing. The output state information is used as a safety Interlock for unsafe gearshift operation. This safety interlock is very important during the starting of the vehicle. The gear shift functionality will be activated if and only if the driver has occupied the seat of the vehicle.

When the vehicle is started, it is cranking on, the safety function for rider seat occupancy is executed. If the seat occupancy status is detected as high and throttle position signal (or TPS) is greater than idle TPS and engine speed greater than maximum idle speed, than driving mode with gear up/down functionality is executed. If engine speed is less than stall speed the vehicle will be started again and if the vehicle tilt angle is greater than maximum threshold safety function for vehicle tilting is executed. After which it is checked if the vehicle tilt angle is less than maximum threshold, then the driving mode with gear up and down functionality is executed.

Referring to Figure 3, when the vehicle is started, the controller goes to step 1 and reads the values of TPS, engine speed, vehicle speed, gear position signal, clutch position signal and brake switch signal. Then it checks for rate of change of TPS and if it is equal to zero and brake signal is not equal to zero which is step 2. If the requirements are met in step 2, it checks for whether engine speed is greater than threshold engine speed, if it comes out in negative, it goes to step 1 and if comes affirmative in step 4 it checks whether gear position is not equal to maximum gear position, if "yes" goes to step 1 and if "no" comes to step 5 and disengages clutch by activating and controlling the position of the clutch actuator. Then in step 6 shifts the gear to the next upper gear by activating the gear shifting actuator. In step 7 it calculates the synchronising engine speed from vehicle speed and wait for it. In step 8 it engages clutch by activating and controlling the position of the clutch actuator.

If requirement of step 2 are not met it goes to step 9 and checks whether engine speed is less than low threshold engine speed. If the requirements are not met gear shifting process is not activated. If the requirements are met in step 9, then it goes to step 10 and checks whether gear position is equal to minimum gear position, if the answer is "yes" gear shifting process is not activated. If the answer is "no" it follows the step 5, 6, 7 and 8.

Referring to Figure 4, the flow chart for interlock function based on seat occupancy sensor is described herein after. When the ignition key is "on" in step 001 it checks whether gear is in neutral position, if it is negative it activates the gear and clutch actuator to bring the gear to neutral position and crank the engine in step 002, if it is affirmative it straight away cranks the engine in step 002. In step 002a it checks whether the side stand is ON/OFF. If the state of side stand is ON (i.e., when the side stand has not been released) it gives a beep sound and again checks the side stand state, it follows the loop till it finds that the side stand is in OFF state ( means side stand has been released). After the side stand is detected in OFF state, in step 003 it checks the driver occupancy sensor output state, if the state is OFF ( means nobody is sitting on the seat) it executes step 004 whereby it deactivates gear and clutch shift actuator and again goes back to step 003 and follows thereafter. If in step 002 the state is ON (means somebody is sitting on the seat) it goes to step 005 and activates the gear and clutch shift actuator according to rider demand.

Referring to Figure 5, the flow chart for interlock function based on tilt angle sensor is described herein after. When the vehicle is started it checks for whether vehicle speed is greater than low threshold value, if the requirements are not met the vehicle is started. If the requirements of step 006 are met, in step 007 it calculates the maximum tilting angle for the particular engine operating point and vehicle speed. Then in the next step 008 it reads the vehicle tilt angle information from tilt angle sensor. In step 009 it checks whether vehicle tilt angle is greater than maximum tilting angle, if it is not so it goes back to step 007 and follows the next steps accordingly. If the requirement in step 009 is met it deactivates the gear and clutch shift actuator in step 010 and again it goes back to step 007 follows the loop.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. A safety device for an automatic manual transmission (AMT) scooter type motor vehicle comprising clutch and shift actuators; a controller for activating the said actuators; a tilt sensor for sensing the angle of lateral inclination of the vehicle while cornering, and feeding this sensed data to the controller; a seat sensor for sensing the presence or absence of the rider on the seat, when the vehicle is being started, and feeding this sensed data to the controller for deactivating the said actuators in the absence of the rider; a side stand sensor for sensing the position of the said stand, when the vehicle is being started and feeding this sensed data to the controller for deactivating the said actuators whenever the position of the said stand is not in the fully raised position.

2. A safety device for an AMT scooter type motor vehicle as claimed in Claim 1 wherein the tilt sensor is mounted horizontally on the PCB of the controller which is placed parallel to the road surface.

3. A safety device for an AMT scooter type motor vehicle as claimed in Claim 1 wherein the controller does not allow any gear shift if the vehicle reaches a predetermined maximum tilt threshold angle for a particular operating point.

4. A safety device for an AMT scooter type motor vehicle as claimed in any one of the preceding Claims wherein the said tilt sensor is bidirectional /single directional, ON/OFF tilt sensor or normally open when placed horizontally.

5. A safety device for an AMT scooter type motor vehicle as claimed in any one of the preceding Claims wherein the said tilt sensor is ON/OFF type, normally open when above switch angle, normally closed when below switch angle.

6. A safety device for an AMT scooter type motor vehicle as claimed in any one of
the preceding Claims wherein the sensor is non-sensitive to vibration when horizontal

7. A safety device for an AMT scooter type motor vehicle substantially as herein described and illustrated