Method of controlling an engine of a motor vehicle

Abstract

A method of controlling an engine of a stop-start enabled motor vehicle is disclosed in which the conditions used to determine whether to stop or start the engine are changed based upon whether maximum driver comfort or maximum fuel economy are requested by a driver of the motor vehicle.

What is claimed is: 
     
         1 . A method of controlling an engine of a stop-start enabled motor vehicle, the engine having at least first and second stop-start modes of operation in each of which stopping of the engine is effected when respective stop conditions are met and starting of the engine is effected when respective start conditions are met and a user input device to select the stop-start mode of operation to be used, wherein the method comprises:
 providing a first set of engine stop conditions for use when the first stop-start mode of operation is selected that is more restrictive than a second set of engine stop conditions for use when the second stop-start mode of operation is selected; and   providing a first set of engine start conditions for use when the first stop-start mode of operation is selected that are less restrictive that a second set of engine start conditions for use when the second stop-start mode of operation is selected.   
     
     
         2 . The method of  claim 1 , wherein there is at least one further engine stop-start mode of operation and a corresponding set of stop conditions and the further stop conditions are less restrictive than the first set of stop conditions and more restrictive than the second set of stop conditions. 
     
     
         3 . The method of  claim 1 , wherein there is at least one further engine stop-start mode of operation and a corresponding set of start conditions and the start conditions are more restrictive than the first set of start conditions and less restrictive than the second set of start conditions. 
     
     
         4 . The method of  claim 1 , wherein the first set of stop and start conditions increase the opportunities to start the engine and minimise the opportunities to stop the engine so as to bias control of the engine towards driver comfort. 
     
     
         5 . The method of  claim 1 , wherein the second set of stop and start conditions maximize the opportunities to stop the engine and minimise the opportunities to start the engine so as to bias control of the engine towards fuel economy. 
     
     
         6 . A system for controlling the operation of an engine of a stop-start enabled motor vehicle, the engine having at least first and second engine stop-start modes of operation in each which stopping of the engine is effected when respective stop conditions are met and starting of the engine is effected when respective start conditions are met, the system comprising:
 a stop-start controller arranged to receive information regarding the operating state of the motor vehicle, information regarding operation of one or more vehicle controls by an operator of the motor vehicle and information from a human machine interface of which engine stop-start mode of operation is selected for use, wherein the stop-start controller is operable to use a first set of engine stop conditions when the first engine stop-start mode of operation is selected and use a second set of engine stop conditions when the second engine stop-start mode of operation is selected, the first set of stop conditions being more restrictive than the second set of stop conditions and is operable to use a first set of engine start conditions when the first engine stop-start mode of operation is selected and use a second set of engine start conditions when the second engine stop-start mode of operation is selected, the first set of start conditions being less restrictive than the second set of start conditions.   
     
     
         7 . The system of  claim 6 , wherein there is at least one further engine stop-start mode of operation and a corresponding set of stop conditions and the further stop conditions are less restrictive than the first set of stop conditions and more restrictive than the second set of stop conditions. 
     
     
         8 . The system of  claim 6 , wherein there is at least one further engine stop-start mode of operation and a corresponding set of start conditions and the further start conditions are more restrictive than the first set of start conditions and less restrictive than the second set of start conditions. 
     
     
         9 . The system of  claim 6 , wherein the first set of stop and start conditions increase the opportunities to start the engine and minimise the opportunities to stop the engine so as to bias control of the engine towards driver comfort. 
     
     
         10 . The system of  claim 6 , wherein the second set of stop and start conditions maximize the opportunities to stop the engine and minimise the opportunities to start the engine so as to bias control of the engine towards fuel economy. 
     
     
         11 . A method of controlling a vehicle comprising:
 in response to user selection, selectively auto-starting an engine in response to a first or second set of engine start conditions and selectively auto-stopping the engine in response to a corresponding first or second set of stop conditions, wherein for a same drive cycle the first sets of stop and start conditions result in non-zero fewer engine stops than the second sets of stop and start conditions.   
     
     
         12 . The method of  claim 11 , wherein the first set of engine stop conditions is more restrictive than the second set of engine stop conditions and the second set of engine start conditions is more restrictive than the first set of engine start conditions. 
     
     
         13 . The method of  claim 12 , further comprising, in response to the user selection, selectively starting the engine in response to a third set of engine start conditions and stopping the engine in response to a third set of engine stop conditions, the third set of start conditions being more restrictive than the first set of start conditions and less restrictive than the second set of start conditions and the third set of stop conditions being less restrictive than the first set of stop conditions and more restrictive than the second set of stop conditions.