1. A method to operate an engine in a cruise mode to run a vehicle, said method comprising the steps: checking whether the vehicle is travelling with a speed greater than a speed threshold; detecting whether an clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold; and configuring said engine to run at a constant speed after detection of pressing of said clutch pedal for said predefined number of times.

2. The method as claimed in claim 1, further comprises identifying a release of an accelerator pedal within a second predefined time interval after detection of the clutch pedal pressed for predefined number of times.

3. The method as claimed in claim 1, wherein said constant speed is a vehicle speed maintained during a last clutch pedal press within the first predefined time interval.

4. The method as claimed in claim 1, wherein said constant speed is a vehicle speed with which the vehicle travels for an initial predefined time interval.

5. The method as claimed in claim 1, wherein exiting from said cruise mode when at least one of a first set of driving conditions is satisfied after configuration of said engine to run in said cruise mode, wherein the first set of driving conditions include said accelerator pedal is in the pressed state; said brake pedal is in the pressed state; and said clutch pedal is in the pressed state.

6. An engine control unit (ECU) 1000 to provide cruise mode for a vehicle, said ECU 1000 comprising at least one interface (101, 102, 103, 104) to receive a vehicle speed, accelerator pedal position, brake pedal position and clutch pedal position; a control means 105 adapted to check whether the vehicle is travelling with a speed greater than a speed threshold; detect whether an clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold; and configure said engine to run at a constant speed based on detection of pressing of said clutch pedal for said predefined number of times.

7. The engine control unit 1000 according to claim 6, wherein said interface (101, 102, 103, 104) is one of an input pin and an input port.

8. The engine control unit 1000 according to claim 6, wherein said control means 105 further configures the engine to come out of cruise mode on detecting at least one of a first set of driving conditions wherein the first set of driving conditions include said accelerator pedal is in the pressed state; said brake pedal is in the pressed state; and said clutch pedal is in the pressed state.

9. The engine control unit 1000 according to claim 6, further comprises said control unit 105 is adapted to identify a release of an accelerator pedal within a second predefined time interval after detection of the clutch pedal pressed for predefined number of times.

10. The engine control unit 1000 according to claim 6, wherein said constant speed is a vehicle speed maintained during a last clutch pedal press within the first predefined time interval. ,TagSPECI:Field of the invention [0001] The invention relates to a method and a device for automatically controlling a speed of a vehicle. Background of the invention [0002] Cruise control is a known technology in road vehicles, wherein a desired cruise speed is set by a driver of the vehicle and then vehicle automatically maintains the set desired cruise speed continuously until the driver of the vehicle intervenes. The cruise control system comprises a set switch by which a specific speed can be selected by the driver as desired cruise speed. The cruise control system improves the driver comfort in steady traffic conditions. A button or a switch is usually provided, for example, on the steering wheel, to the driver to activate cruise control in the vehicle. The cruise control may also have separate "on” and “off” switches. The cruise control systems can also have buttons for "set", "accelerate", “cancel”, "resume", and "coast" functions to enable respective operations of the cruise control. In these cruise control systems, the driver has to manually activate the switches to activate/deactivate corresponding cruise control functions. This may be a difficult task while driving. [0003] With the advent of engine management system and the dynamics with which the software can control the drivability characteristics, cruise behavior can be replicated without any need for a physical input (buttons).from the driver. This would reduce the components needed to make up a cruise system and the complex software that would be developed to monitor these signals. [0004] The Indian patent application, 429/CHE/2014, discloses an engine control unit (ECU) for providing cruise mode in a vehicle. The ECU comprises a first interface to receive a vehicle speed; a second interface to detect pressed and released states of an accelerator pedal; a control means to configure engine to run in a cruise mode if said vehicle speed was approximately constant for a pre-defined duration just before the accelerator pedal entered into released state. [0005] In the prior art, the cruise mode gets activated without driver’s intention (unintended acceleration) when the driver maintains a constant speed for the pre-defined duration and removes the foot from the acceleration pedal. Hence, an improved method of automatic cruise control is required to overcome the above mentioned problems. Short description of the drawing [0006] An exemplifying embodiment of the invention is explained in principle below with reference to the drawings. The drawings are, [0007] Figure 1 illustrates a schematic block diagram of an engine control unit to provide a cruise mode for a vehicle in accordance with this invention; and [0008] Figure 2 illustrates a flowchart of a method to operate the engine in the cruise mode in accordance with this invention. Description of the invention [0009] Figure 1 illustrates an engine control unit (ECU) 1000 to provide cruise mode for a vehicle in accordance with this invention. The ECU 1000 comprises at least one interface (101, 102, 103, 104) to receive a vehicle speed, an accelerator pedal position, a brake pedal position and a clutch pedal position. A control means 105 of the ECU 1000 is adapted to check whether the vehicle is travelling with a speed greater than a speed threshold; detect whether an clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold; and configure the engine to run at a constant speed based on detection of pressing of the clutch pedal for said predefined number of times. [00010] The ECU 1000 comprises a microcontroller, a memory unit, input and output ports, different functions and logics to control the engine. All of these parts are not shown in Figure 1. Only the components which are required to describe the invention are disclosed in the Figure 1. An interface of the ECU 1000 receives engine operating conditions from several sensors which are not shown in Figure 1. The engine operating conditions are, for example, an engine speed, an engine temperature, an engine load, an accelerator pedal position, a brake pedal position, a clutch pedal position, etc. The first interface 101 obtains a vehicle speed from a vehicle speed sensor located in the vehicle. [00011] The input ports are configured as a first interface 101, a second interface 102, a third interface 103 and a fourth interface 104. The first interface 101 is connected to a vehicle speed sensor which is located in the vehicle. The second interface 102 is connected to a sensor which provides position of accelerator pedal. Similarly the third interface 103 and fourth interfaces 104 are connected to sensors which provide position of brake pedal and clutch pedal respectively. [00012] The control means 105 receives engine operating conditions from various sensors which are not shown in Figure 1. The engine operating conditions may comprise engine speed, vehicle speed, engine temperature, ambient temperature, ambient pressure, engine load, torque demand, accelerator pedal position, brake pedal position etc. This list is only for illustration and not complete. The control means 105 computes the amount of fuel to be injected into the cylinder for the given engine operating conditions. Hence, the control means 105 controls the injectors and are not shown. [00013] The control means 105 according to the invention provides a feature where the cruise mode is triggered automatically on meeting certain conditions. The control means 105 receives sensor outputs from different sensors regarding the pressing and releasing of the accelerator pedal, the brake pedal and the clutch pedal respectively. The position of the accelerator pedal is sensed by a sensor and the signal is supplied to the control means 105. When the driver of the vehicle presses the accelerator pedal, the control means 105 detects the accelerator pedal to be in the pressed state. Released state of accelerator pedal is the one where the driver has removed his leg completely from the accelerator pedal. Same with the clutch pedal and brake pedal release states. [00014] The control means 105 checks whether the vehicle is travelling with a speed greater than a speed threshold. The speed threshold is a vehicle speed set by the user above which the cruise mode for the vehicle can be activated. The speed threshold is predefined by the user. An option may be provided to the user to change the value of the speed threshold via an interface of the engine control unit 1000. [00015] The control means 105 detects whether the clutch pedal is pressed for a predefined number of times within a first predefined time interval from the instant when the vehicle is travelling with a speed greater than the speed threshold. In an embodiment, the value of the predefined number of times is two. That is, the control means 105 detects whether the clutch pedal is pressed twice within the first predefined time interval from the instant when the vehicle is travelling with a speed greater than the speed threshold. The first predefined time interval is, for example, 5 seconds. The first predefined time interval is defined by the user of the vehicle. The time period of the first predefined time interval starts, when the user of the vehicle presses the clutch pedal for the first time when the vehicle is travelling with the speed greater than the speed threshold. [00016] Once the control means 105 detects the clutch pedal being pressed for the predefined number of times with the first predefined time interval, the control means 105 configures the engine to run at a constant speed. When the engine enters the cruise mode, the user may optionally be notified using audio or visual means for example by a voice message. [00017] In an embodiment, the constant speed is a vehicle speed maintained during a last clutch pedal press within the first predefined time interval. The control means 105 activates the cruise mode with a vehicle speed set equal to a speed maintained during a last clutch pedal press within the first predefined time interval. In an example, if the user selects “three” as the predefined number of times to press the clutch pedal within the first predefined time interval, then the cruise mode is set with the speed maintained during the third clutch pedal press. [00018] In another embodiment, the constant speed is a vehicle speed maintained during a first clutch pedal press within the first predefined time interval. The control means 105 activates the cruise mode with a vehicle speed set equal to a speed maintained during the first clutch pedal press within the first predefined time interval. In an example, if the user selects “two” as the predefined number of times to press the clutch pedal within the first predefined time interval, then the cruise mode is set with the speed maintained during the first clutch pedal press. [00019] In another embodiment, the constant speed is a vehicle speed maintained during the first predefined time interval. The control means 105 activates the cruise mode with a vehicle speed set equal to a speed maintained during the first predefined time interval till the last clutch pedal press. In an example, if the user selects “three” as the predefined number of times to press the clutch pedal within the first predefined time interval, then the cruise mode is set with the speed maintained during the first predefined time interval from the first clutch pedal press to the third clutch pedal press. [00020] In another embodiment, the constant speed is a vehicle speed with which the vehicle travels for an initial predefined time interval. The control means 105 checks whether the vehicle is travelling with a constant speed for an initial predefined time interval before the pressing of the clutch pedal for a predefined number of times. The engine control unit 1000 allows the user to set a value for the initial predefined time interval for which the user has to maintain the constant speed for the vehicle movement. Upon detection of the pressing of the clutch pedal for the predefined number of times after maintaining the constant speed for the initial predefined time interval, the control means 105 sets the cruise mode for the vehicle at the constant speed. [00021] Once the control means 105 detects the clutch pedal being pressed for the predefined number of times within the first predefined time interval, the control means 105 detects whether the accelerator pedal is released within the second predefined time interval. The control means 105 configures the engine to run in a cruise mode, with the user being notified using audio or visual means, for example by a voice message. [00022] In an embodiment, the control means 105 identifies whether the accelerator pedal is released from the pressed position within a second predefined time interval. The control means 105 identifies the position of the accelerator pedal after the detection of the clutch pedal being pressed for the predefined number of times. The second predefined time interval is defined by the user of the vehicle. The time period for the second predefined time interval starts from the time the control means 105 detects the last clutch press. If the control means 105 identifies the accelerator pedal being released from the pressed position, that is, when the accelerator pedal is not in the pressed position, then the control means 105 configures the engine to run in a cruise mode at the current speed constantly based on detection of the accelerator pedal in the released state. [00023] Configuring the engine to maintain constant speed may be achieved by electronic throttle control which is not shown. In electronic throttle control, the throttle opening and closing is controlled electronically using a motor or any other actuator. Depending upon the constant speed to be attained and other engine operating conditions, the control means 105 determines the amount of air to be sucked in the intake manifold which is not shown. Depending upon the amount of air to be sucked in, the throttle is controlled accordingly. According to the air sucked into the intake manifold, the control means 105 determines the amount of fuel to be injected and injects accordingly. This cycle is continued and maintained so that the engine speed is maintained at the constant speed. [00024] Whenever the driver presses either the clutch pedal or brake pedal or accelerator pedal, the control means 105 de-activates the cruise mode. Now the engine runs under normal mode where the engine speed is directly influenced by the position of the accelerator pedal. [00025] In the embodiment, the engine control unit 1000 as shown in Figure 1 performs the normal engine operation and also cruise control. In another embodiment it is possible that the engine control is done by the ECU 1000 and the cruise control may be performed by an independent electronic device. [00026] The first input interface 101 is an input pin or an input port which is connected to a vehicle speed sensor. Similarly the second interface 102 is an input pin or an input port which is connected to a sensor which provides position of accelerator pedal. The control means 105 in the ECU 1000 continuously stores a pre-defined number of samples of vehicle speed to determine one of the conditions for trigger of cruise mode. Once all the conditions to enter into cruise mode are met, the control means 105 configures the engine to maintain the constant speed. The cruise mode is the mode in which the engine runs with a constant speed when the accelerator pedal is in released state. The control means 105 further configures engine to come out of cruise mode on detecting press of a brake pedal or press of the accelerator pedal or press of a clutch pedal. [00027] In the embodiment in Figure 1, it is shown that the ECU 1000 is having different interfaces (101, 102, 103, 104) to read vehicle speed, position of accelerator pedal, position of brake pedal and position of clutch pedal respectively. In another embodiment there may be a single interface reading the vehicle speed, position of accelerator pedal, position of brake pedal and position of clutch pedal. [00028] As there is no need for separate button/switch and related components to activate/set the cruise mode, the associated hardware and software costs are reduced. [00029] Figure 2 illustrates a flowchart of a method to operate the engine in the cruise mode in accordance with this invention. At step S1, the control means 105 checks whether the vehicle is travelling with a speed greater than the speed threshold. At step S2, the control means 105 detects whether the clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold. At step S3, the control means 105 configures the engine to run at a constant speed after detection of the clutch pedal for the predefined number of times. [00030] As explained earlier, pressing of the clutch pedal for the predefined number of times is considered as a trigger to activate the cruise mode. In the cruise mode, the engine is made to run at the current speed constantly. The cruise mode is deactivated when one of the accelerated pedal, clutch pedal or the brake pedal is pressed. The invention enables the user/driver to activate a cruise mode without need for dedicated button and related hardware. Hence it also provides the options to easily activate cruise mode only with legs. [00031] It must be understood that the embodiments explained and the example provided in the above detailed description in only illustrative and does not limit the scope of this invention. The scope of this invention is limited only by the scope of the claims. Many modification and changes in the embodiments aforementioned are envisaged and are within the scope of this invention.

CLIAMS:We claim:
1. A method to operate an engine in a cruise mode to run a vehicle, said method comprising the steps:
checking whether the vehicle is travelling with a speed greater than a speed threshold;
detecting whether an clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold; and
configuring said engine to run at a constant speed after detection of pressing of said clutch pedal for said predefined number of times.
2. The method as claimed in claim 1, further comprises identifying a release of an accelerator pedal within a second predefined time interval after detection of the clutch pedal pressed for predefined number of times.
3. The method as claimed in claim 1, wherein said constant speed is a vehicle speed maintained during a last clutch pedal press within the first predefined time interval.
4. The method as claimed in claim 1, wherein said constant speed is a vehicle speed with which the vehicle travels for an initial predefined time interval.
5. The method as claimed in claim 1, wherein exiting from said cruise mode when at least one of a first set of driving conditions is satisfied after configuration of said engine to run in said cruise mode, wherein the first set of driving conditions include

said accelerator pedal is in the pressed state;
said brake pedal is in the pressed state; and
said clutch pedal is in the pressed state.
6. An engine control unit (ECU) 1000 to provide cruise mode for a vehicle, said ECU 1000 comprising
at least one interface (101, 102, 103, 104) to receive a vehicle speed, accelerator pedal position, brake pedal position and clutch pedal position;
a control means 105 adapted to
check whether the vehicle is travelling with a speed greater than a speed threshold;
detect whether an clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold; and
configure said engine to run at a constant speed based on detection of pressing of said clutch pedal for said predefined number of times.
7. The engine control unit 1000 according to claim 6, wherein said interface (101, 102, 103, 104) is one of an input pin and an input port.
8. The engine control unit 1000 according to claim 6, wherein said control means 105 further configures the engine to come out of cruise mode on detecting at least one of a first set of driving conditions wherein the first set of driving conditions include

said accelerator pedal is in the pressed state;
said brake pedal is in the pressed state; and
said clutch pedal is in the pressed state.
9. The engine control unit 1000 according to claim 6, further comprises said control unit 105 is adapted to identify a release of an accelerator pedal within a second predefined time interval after detection of the clutch pedal pressed for predefined number of times.
10. The engine control unit 1000 according to claim 6, wherein said constant speed is a vehicle speed maintained during a last clutch pedal press within the first predefined time interval. ,TagSPECI:Field of the invention
[0001] The invention relates to a method and a device for automatically controlling a speed of a vehicle.
Background of the invention
[0002] Cruise control is a known technology in road vehicles, wherein a desired cruise speed is set by a driver of the vehicle and then vehicle automatically maintains the set desired cruise speed continuously until the driver of the vehicle intervenes. The cruise control system comprises a set switch by which a specific speed can be selected by the driver as desired cruise speed. The cruise control system improves the driver comfort in steady traffic conditions. A button or a switch is usually provided, for example, on the steering wheel, to the driver to activate cruise control in the vehicle. The cruise control may also have separate "on” and “off” switches. The cruise control systems can also have buttons for "set", "accelerate", “cancel”, "resume", and "coast" functions to enable respective operations of the cruise control. In these cruise control systems, the driver has to manually activate the switches to activate/deactivate corresponding cruise control functions. This may be a difficult task while driving.
[0003] With the advent of engine management system and the dynamics with which the software can control the drivability characteristics, cruise behavior can be replicated without any need for a physical input (buttons).from the driver. This would reduce the components needed to make up a cruise system and the complex software that would be developed to monitor these signals.
[0004] The Indian patent application, 429/CHE/2014, discloses an engine control unit (ECU) for providing cruise mode in a vehicle. The ECU comprises a first interface to receive a vehicle speed; a second interface to detect pressed and released states of an accelerator pedal; a control means to configure engine to run in a cruise mode if said vehicle speed was approximately constant for a pre-defined duration just before the accelerator pedal entered into released state.
[0005] In the prior art, the cruise mode gets activated without driver’s intention (unintended acceleration) when the driver maintains a constant speed for the pre-defined duration and removes the foot from the acceleration pedal. Hence, an improved method of automatic cruise control is required to overcome the above mentioned problems.
Short description of the drawing
[0006] An exemplifying embodiment of the invention is explained in principle below with reference to the drawings. The drawings are,
[0007] Figure 1 illustrates a schematic block diagram of an engine control unit to provide a cruise mode for a vehicle in accordance with this invention; and
[0008] Figure 2 illustrates a flowchart of a method to operate the engine in the cruise mode in accordance with this invention.
Description of the invention
[0009] Figure 1 illustrates an engine control unit (ECU) 1000 to provide cruise mode for a vehicle in accordance with this invention. The ECU 1000 comprises at least one interface (101, 102, 103, 104) to receive a vehicle speed, an accelerator pedal position, a brake pedal position and a clutch pedal position. A control means 105 of the ECU 1000 is adapted to check whether the vehicle is travelling with a speed greater than a speed threshold; detect whether an clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold; and configure the engine to run at a constant speed based on detection of pressing of the clutch pedal for said predefined number of times.
[00010] The ECU 1000 comprises a microcontroller, a memory unit, input and output ports, different functions and logics to control the engine. All of these parts are not shown in Figure 1. Only the components which are required to describe the invention are disclosed in the Figure 1. An interface of the ECU 1000 receives engine operating conditions from several sensors which are not shown in Figure 1. The engine operating conditions are, for example, an engine speed, an engine temperature, an engine load, an accelerator pedal position, a brake pedal position, a clutch pedal position, etc. The first interface 101 obtains a vehicle speed from a vehicle speed sensor located in the vehicle.
[00011] The input ports are configured as a first interface 101, a second interface 102, a third interface 103 and a fourth interface 104. The first interface 101 is connected to a vehicle speed sensor which is located in the vehicle. The second interface 102 is connected to a sensor which provides position of accelerator pedal. Similarly the third interface 103 and fourth interfaces 104 are connected to sensors which provide position of brake pedal and clutch pedal respectively.
[00012] The control means 105 receives engine operating conditions from various sensors which are not shown in Figure 1. The engine operating conditions may comprise engine speed, vehicle speed, engine temperature, ambient temperature, ambient pressure, engine load, torque demand, accelerator pedal position, brake pedal position etc. This list is only for illustration and not complete. The control means 105 computes the amount of fuel to be injected into the cylinder for the given engine operating conditions. Hence, the control means 105 controls the injectors and are not shown.
[00013] The control means 105 according to the invention provides a feature where the cruise mode is triggered automatically on meeting certain conditions. The control means 105 receives sensor outputs from different sensors regarding the pressing and releasing of the accelerator pedal, the brake pedal and the clutch pedal respectively. The position of the accelerator pedal is sensed by a sensor and the signal is supplied to the control means 105. When the driver of the vehicle presses the accelerator pedal, the control means 105 detects the accelerator pedal to be in the pressed state. Released state of accelerator pedal is the one where the driver has removed his leg completely from the accelerator pedal. Same with the clutch pedal and brake pedal release states.
[00014] The control means 105 checks whether the vehicle is travelling with a speed greater than a speed threshold. The speed threshold is a vehicle speed set by the user above which the cruise mode for the vehicle can be activated. The speed threshold is predefined by the user. An option may be provided to the user to change the value of the speed threshold via an interface of the engine control unit 1000.
[00015] The control means 105 detects whether the clutch pedal is pressed for a predefined number of times within a first predefined time interval from the instant when the vehicle is travelling with a speed greater than the speed threshold. In an embodiment, the value of the predefined number of times is two. That is, the control means 105 detects whether the clutch pedal is pressed twice within the first predefined time interval from the instant when the vehicle is travelling with a speed greater than the speed threshold. The first predefined time interval is, for example, 5 seconds. The first predefined time interval is defined by the user of the vehicle. The time period of the first predefined time interval starts, when the user of the vehicle presses the clutch pedal for the first time when the vehicle is travelling with the speed greater than the speed threshold.
[00016] Once the control means 105 detects the clutch pedal being pressed for the predefined number of times with the first predefined time interval, the control means 105 configures the engine to run at a constant speed. When the engine enters the cruise mode, the user may optionally be notified using audio or visual means for example by a voice message.
[00017] In an embodiment, the constant speed is a vehicle speed maintained during a last clutch pedal press within the first predefined time interval. The control means 105 activates the cruise mode with a vehicle speed set equal to a speed maintained during a last clutch pedal press within the first predefined time interval. In an example, if the user selects “three” as the predefined number of times to press the clutch pedal within the first predefined time interval, then the cruise mode is set with the speed maintained during the third clutch pedal press.
[00018] In another embodiment, the constant speed is a vehicle speed maintained during a first clutch pedal press within the first predefined time interval. The control means 105 activates the cruise mode with a vehicle speed set equal to a speed maintained during the first clutch pedal press within the first predefined time interval. In an example, if the user selects “two” as the predefined number of times to press the clutch pedal within the first predefined time interval, then the cruise mode is set with the speed maintained during the first clutch pedal press.
[00019] In another embodiment, the constant speed is a vehicle speed maintained during the first predefined time interval. The control means 105 activates the cruise mode with a vehicle speed set equal to a speed maintained during the first predefined time interval till the last clutch pedal press. In an example, if the user selects “three” as the predefined number of times to press the clutch pedal within the first predefined time interval, then the cruise mode is set with the speed maintained during the first predefined time interval from the first clutch pedal press to the third clutch pedal press.
[00020] In another embodiment, the constant speed is a vehicle speed with which the vehicle travels for an initial predefined time interval. The control means 105 checks whether the vehicle is travelling with a constant speed for an initial predefined time interval before the pressing of the clutch pedal for a predefined number of times. The engine control unit 1000 allows the user to set a value for the initial predefined time interval for which the user has to maintain the constant speed for the vehicle movement. Upon detection of the pressing of the clutch pedal for the predefined number of times after maintaining the constant speed for the initial predefined time interval, the control means 105 sets the cruise mode for the vehicle at the constant speed.

[00021] Once the control means 105 detects the clutch pedal being pressed for the predefined number of times within the first predefined time interval, the control means 105 detects whether the accelerator pedal is released within the second predefined time interval. The control means 105 configures the engine to run in a cruise mode, with the user being notified using audio or visual means, for example by a voice message.
[00022] In an embodiment, the control means 105 identifies whether the accelerator pedal is released from the pressed position within a second predefined time interval. The control means 105 identifies the position of the accelerator pedal after the detection of the clutch pedal being pressed for the predefined number of times. The second predefined time interval is defined by the user of the vehicle. The time period for the second predefined time interval starts from the time the control means 105 detects the last clutch press. If the control means 105 identifies the accelerator pedal being released from the pressed position, that is, when the accelerator pedal is not in the pressed position, then the control means 105 configures the engine to run in a cruise mode at the current speed constantly based on detection of the accelerator pedal in the released state.
[00023] Configuring the engine to maintain constant speed may be achieved by electronic throttle control which is not shown. In electronic throttle control, the throttle opening and closing is controlled electronically using a motor or any other actuator. Depending upon the constant speed to be attained and other engine operating conditions, the control means 105 determines the amount of air to be sucked in the intake manifold which is not shown. Depending upon the amount of air to be sucked in, the throttle is controlled accordingly. According to the air sucked into the intake manifold, the control means 105 determines the amount of fuel to be injected and injects accordingly. This cycle is continued and maintained so that the engine speed is maintained at the constant speed.

[00024] Whenever the driver presses either the clutch pedal or brake pedal or accelerator pedal, the control means 105 de-activates the cruise mode. Now the engine runs under normal mode where the engine speed is directly influenced by the position of the accelerator pedal.
[00025] In the embodiment, the engine control unit 1000 as shown in Figure 1 performs the normal engine operation and also cruise control. In another embodiment it is possible that the engine control is done by the ECU 1000 and the cruise control may be performed by an independent electronic device.
[00026] The first input interface 101 is an input pin or an input port which is connected to a vehicle speed sensor. Similarly the second interface 102 is an input pin or an input port which is connected to a sensor which provides position of accelerator pedal. The control means 105 in the ECU 1000 continuously stores a pre-defined number of samples of vehicle speed to determine one of the conditions for trigger of cruise mode. Once all the conditions to enter into cruise mode are met, the control means 105 configures the engine to maintain the constant speed. The cruise mode is the mode in which the engine runs with a constant speed when the accelerator pedal is in released state. The control means 105 further configures engine to come out of cruise mode on detecting press of a brake pedal or press of the accelerator pedal or press of a clutch pedal.
[00027] In the embodiment in Figure 1, it is shown that the ECU 1000 is having different interfaces (101, 102, 103, 104) to read vehicle speed, position of accelerator pedal, position of brake pedal and position of clutch pedal respectively. In another embodiment there may be a single interface reading the vehicle speed, position of accelerator pedal, position of brake pedal and position of clutch pedal.

[00028] As there is no need for separate button/switch and related components to activate/set the cruise mode, the associated hardware and software costs are reduced.
[00029] Figure 2 illustrates a flowchart of a method to operate the engine in the cruise mode in accordance with this invention. At step S1, the control means 105 checks whether the vehicle is travelling with a speed greater than the speed threshold. At step S2, the control means 105 detects whether the clutch pedal is pressed for a predefined number of times within a first predefined time interval when the vehicle is travelling with the speed greater than the speed threshold. At step S3, the control means 105 configures the engine to run at a constant speed after detection of the clutch pedal for the predefined number of times.
[00030] As explained earlier, pressing of the clutch pedal for the predefined number of times is considered as a trigger to activate the cruise mode. In the cruise mode, the engine is made to run at the current speed constantly. The cruise mode is deactivated when one of the accelerated pedal, clutch pedal or the brake pedal is pressed. The invention enables the user/driver to activate a cruise mode without need for dedicated button and related hardware. Hence it also provides the options to easily activate cruise mode only with legs.
[00031] It must be understood that the embodiments explained and the example provided in the above detailed description in only illustrative and does not limit the scope of this invention. The scope of this invention is limited only by the scope of the claims. Many modification and changes in the embodiments aforementioned are envisaged and are within the scope of this invention.