Method and device for controlling an internal combustion engine in stop/start operation
First Claim
1. A method for controlling an internal combustion engine for a motor vehicle in stop-start operation, comprising the steps of:
- in response to a request for a switch-off of the internal combustion engine, controllably reducing the torque produced by the internal combustion engine while fuel injection is continued such that the speed of the internal combustion engine falls to below a predetermined setpoint idling speed,wherein the torque reduction is controlled such that the speed of the internal combustion engine is reduced in a controlled manner from (a) the predetermined setpoint idling speed (b) to a fuel injection switch-off speed at which a predetermined condition is met, the controlled manner of the speed reduction providing a less rapid reduction of speed than if the fuel injection was stopped upon the request for the switch-off of the internal combustion engine,if the request for switch-off of the internal combustion engine is canceled during the reduction of torque from the predetermined setpoint idling speed to the fuel injection switch-off speed, and before the fuel injection switch-off speed is reached, increasing the torque to or above the predetermined setpoint idling speed; and
if the request for switch-off of the internal combustion engine is not canceled by the time the fuel injection switch-off speed is reached, switching off the fuel injection such that the speed of the internal combustion engine rapidly falls to zero.
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Accused Products
Abstract
In a method for controlling an internal combustion engine (1) for a motor vehicle in stop-start operation, the internal combustion engine (1) is operated in the idling operating state. If there is a request for switch-off of the internal combustion engine (1) the torque produced by the internal combustion engine (1) is reduced while fuel continues to be injected. The fuel injection is switched off if the speed of the internal combustion engine (1) reaches a predetermined minimum value. The torque produced by the internal combustion engine (1) is increased again if the request for switching off the internal combustion engine (1) is canceled before the minimum speed is reached.
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Citations
18 Claims
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1. A method for controlling an internal combustion engine for a motor vehicle in stop-start operation, comprising the steps of:
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in response to a request for a switch-off of the internal combustion engine, controllably reducing the torque produced by the internal combustion engine while fuel injection is continued such that the speed of the internal combustion engine falls to below a predetermined setpoint idling speed, wherein the torque reduction is controlled such that the speed of the internal combustion engine is reduced in a controlled manner from (a) the predetermined setpoint idling speed (b) to a fuel injection switch-off speed at which a predetermined condition is met, the controlled manner of the speed reduction providing a less rapid reduction of speed than if the fuel injection was stopped upon the request for the switch-off of the internal combustion engine, if the request for switch-off of the internal combustion engine is canceled during the reduction of torque from the predetermined setpoint idling speed to the fuel injection switch-off speed, and before the fuel injection switch-off speed is reached, increasing the torque to or above the predetermined setpoint idling speed; and if the request for switch-off of the internal combustion engine is not canceled by the time the fuel injection switch-off speed is reached, switching off the fuel injection such that the speed of the internal combustion engine rapidly falls to zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A control device for an internal combustion engine of a motor vehicle, the control device being operable, in stop-start operation, to:
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in response to a request for a switch-off of the internal combustion engine, controllably reducing the torque produced by the internal combustion engine while fuel injection is continued such that the speed of the internal combustion engine falls to below a predetermined setpoint idling speed, control the torque reduction such that the speed of the internal combustion engine is reduced in a controlled manner from (a) the predetermined setpoint idling speed (b) to a fuel injection switch-off speed at which a predetermined condition is met, the controlled manner of the speed reduction providing a less rapid reduction of speed than if the fuel injection was stopped upon the request for the switch-off of the internal combustion engine, if the request for switch-off of the internal combustion engine is canceled during the reduction of torque from the predetermined setpoint idling speed to the fuel injection switch-off speed, and before the fuel injection switch-off speed is reached, increase the torque to or above the predetermined setpoint idling speed; and if the request for switch-off of the internal combustion engine is not canceled by the time the fuel injection switch-off speed is reached, switch off the fuel injection such that the speed of the internal combustion engine rapidly falls to zero. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification