Field of the invention:
The invention relates to automatic start-stop system for vehicles.

Background of the invention:
Start-stop systems are included in vehicles so that the unnecessary consumption of fuel can be avoided when the vehicle needs to halt for small time periods during a driving cycle like at traffic signals. The start-stop system halts the engine operation either via driver input or automatically for the brief time period. Once the driver input indicates demand for movement of the vehicle, the engine is started automatically. Most of the presently available start-stop systems are provided with a switch or similar hardware elements to de-activate or disable the start-stop feature in the vehicle as per the driver requirement.

The proposed concept eliminates the need of a hardware interface like switch or push button for disabling the start-stop system.

Brief description of the invention:
It is an object of the present invention to reduce or remove the hardware elements required in a start-stop system. In accordance with the present invention a method to disable activation of a start-stop system of a vehicle is disclosed. According to the proposed method an indication is given to a driver of a state of the vehicle which satisfies the criteria for activation of the start-stop system. In case the driver wants to disable the activation of the start-stop system, instead of using a hardware switch, the driver needs to open and close the throttle of the vehicle in a predefined pattern. On detecting the variation in the throttle signal within a predefined time period the activation of the start-stop system is disabled.

In accordance with the present invention the hardware used for disabling the start-stop system from activating can be eliminated. The start-stop switch or push button, ""' wiring, fabrication of the housing, ECU pins dedicated for the start-stop system all can be avoided. Thus, the present invention contributes to reducing the cost of start-stop systems.

Further the user has an additional option of disabling the start stop system temporarily or permanently for the current drive cycle.
Brief description of the drawings:
The present invention is described with reference to the following drawing, Fig. 1 illustrates a flowchart for the method for disabling the start-stop system activation in accordance with the present invention.

Detailed description of the drawings:
Fig. 1 illustrates a method in accordance with the present invention for disabling the activation of start-stop system in case the driver does not want the start-stop mode enabled. For vehicles which have automatic activation of start-stop system, different vehicle parameters are continuously monitored. An indication is given to the driver of a state of the vehicle satisfying criteria for the automatic activation of the start-stop system (10). In case the driver does not intend to stop the vehicle for a significant time and does not wish to activate the start-stop mode, the driver opens and closes the throttle of the vehicle in a predefined pattern (12). Variations in the throttle signal are detected (14) and the automatic activation of the start-stop system is disabled (16) based on the same.

Typically vehicles with automatic activation of start-stop mode have means to monitor different vehicle parameters. Based on the status of these parameters the automatic activation of the start-stop system is carried out. When these parameters reach the threshold, the vehicle will automatically switch to a start-stop mode, an indication is given to the driver of an impending activation of start-stop system by an indicator. This indicator can be in form of a blinking light on the instrument cluster. After the light indicating an impending start-stop mode starts blinking, the driver has to give input within a predefined time window indicating that he does not wish to activate the start-stop. If the user does not give any input after the indication, then the start-stop mode is automatically activated. If within the predefined time period the user operates the throttle and opens and closes it in a predefined manner, then the change in the throttle signal is detected and the activation of start-stop mode is disabled.

In accordance with one embodiment of the invention, if it is detected that the driver opens and closes the throttle only once then the start-stop mode activation is disabled for that instant in the drive cycle. The next instant in that same drive cycle when the status of the parameters again indicates impending activation of start-stop mode, unless the user again gives an input, the start-stop mode will get activated.

In accordance with another embodiment of the invention, if it is detected that the driver opens and closes the throttle more than once within a specific time period then the activation of the start-stop mode is disabled for the entire drive cycle. Thus, even though if later during the drive cycle there is condition which would have triggered an indication for an impending automatic activation of the start-stop mode, the mode remains disabled.

When the vehicle ignition is switched OFF and ON again, the start-stop system gets reset and any input from the driver disabling the start-stop system is also reset.

The method in accordance with the present invention is implemented by a control unit for start-stop systems. The control unit is adapted to receive different vehicle parameters for automatic start-stop activation. Based on these parameters the control unit is adapted to give an indication to a driver of impending automatic start-stop activation. The control unit receives inputs from a throttle opening sensor. If the driver does not wish the start-stop system to be enabled, then he can vary the throttle position so that the control unit detects these variations in the throttle signal and disable the automatic activation of the start-stop system accordingly. If the driver opens and closes the throttle once then the activation of the start-stop system is disabled temporarily and if the throttle is opened more than once in quick succession with a predefined time period then the automatic activation of the start-stop system is disabled permanently for that particular drive cycle. Once the ignition is turned OFF the system is reset.

It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.

WE CLAIM:
1. A method to disable activation of a start-stop system of a vehicle, said method comprising the following steps indicating to a driver a state of the vehicle satisfying criteria for activation of the start-stop system (10); opening and closing the throttle of the vehicle by the driver in a predefined pattern (12); detecting the variation in the throttle signal (14); and disabling the activation of the start-stop system based on the throttle signal variations (16).

2. A method as claimed in claim (1) wherein indicating to the driver of an impending activation of start-stop system is by a visual light indicator.

3. A method as claimed in claim (1) wherein the opening and closing of throttle of the vehicle by the driver is to be done within a predefined time window after the indication of impending activation of start-stop system is given to the driver.

4. A method as claimed in claim (1) wherein disabling of the start-stop system is temporary or permanent for that drive cycle depending on the throttle opening pattern.

5. A method as claimed in claim (1) wherein for temporary disabling of the activation of the start-stop system the throttle is opened and closed once within the predefined time window.

6. A method as claimed in claim (1) wherein for permanent disabling of the activation of the start-stop system in the current driving cycle the throttle is opened and closed more than once within a predefined time window.

7. A method as claimed in claim (1) wherein the start-stop system is activated in case the driver does not give any throttle input within the predefined time window when there is an indication of impending start-stop activation

8. A method as claimed in claim (1) wherein resetting the ignition key to ON position enables the start-stop activation system.

9. A control unit for start-stop systems, said control unit adapted to receive different vehicle parameters for automatic start-stop activation, wherein said control unit is adapted to give an indication to a driver of impending automatic start-stop activation; to receive inputs from a throttle opening sensor and disable the automatic activation of the start-stop system when variations are observed in the throttle signal.