초록

A method and system that responds to non-propulsive needs of a hybrid vehicle by setting at least two thresholds related to engine support: one threshold to keep a running engine ON and a another threshold to turn the engine ON from an OFF state.

대표청구항 ▼

1. A method of reducing the number of times a main power unit of a hybrid electric vehicle is activated to support a plurality of auxiliary system of the vehicle during a given drive cycle comprising a sequence of the following steps: determining the ON/OFF status of said unit; if the unit is ON

1. A method of reducing the number of times a main power unit of a hybrid electric vehicle is activated to support a plurality of auxiliary system of the vehicle during a given drive cycle comprising a sequence of the following steps: determining the ON/OFF status of said unit; if the unit is ON requesting that the unit be maintained ON until the value of an auxiliary system parameter exceeds a first threshold value wherein said first threshold value is a unit ON auxiliary system threshold value; if the unit is OFF requesting that the unit be turned ON when the value of said parameter falls below a second threshold value wherein said second threshold value is a unit OFF auxiliary system threshold value; setting said unit OFF auxiliary system threshold value when the status of said unit is OFF; setting said unit ON auxiliary system threshold value when the status of said unit is ON; and wherein said step of requesting that a unit ON status be maintained is performed if a predetermined parameter in any of said plurality of auxiliary systems is below respective unit ON auxiliary system threshold values, and said step of requesting a unit ON status is performed if a predetermined parameter in any of said plurality of auxiliary systems is below respective unit OFF auxiliary system threshold value. 2. The method of claim 1 wherein said auxiliary system is a brake booster vacuum system. 3. The method of claim 1 wherein said auxiliary system is an air conditioning and heating system. 4. The method of claim 1 wherein said auxiliary system is a purge vapor system. 5. The method of claim 1 wherein said auxiliary system is a catalyst system. 6. A method of reducing the number of times a main power unit of a hybrid electric vehicle is activated to support an auxiliary system of the vehicle during a given drive cycle comprising a sequence of the following steps: determining the ON/OFF status of said unit; determining whether the value of an auxiliary system parameter is within or outside a window defined by first and second threshold values, where said first threshold value represents a parameter value to be attained before a unit that is ON should be turned OFF and the second threshold value represents a parameter value at which it is desirable for a unit that is OFF to be turned ON; requesting a change of status from OFF to ON if the value of the parameter falls below said second threshold value; and requesting a change of status from ON to OFF if the value of the parameter is greater than said first threshold value. 7. A system for reducing the number of times a main power unit of a hybrid electric vehicle is activated to support an auxiliary system of the vehicle during a given drive cycle comprising: means for determining the ON/OFF status of said unit; means for determining whether the value of an auxiliary system parameter is within or outside a window defined by first and second threshold values, where said first threshold value represents a parameter value to be attained before a unit that is ON should be turned OFF and the second threshold value represents a parameter value at which it is desirable for a unit that is OFF to be turned ON; means for requesting a change of status from OFF to ON if the value of the parameter falls below said second threshold value; and means for requesting a change of status from ON to OFF if the value of the parameter is greater than said first threshold value. 8. The system of claim 7 further comprising: means for setting said unit OFF auxiliary system threshold value when the status of said unit is OFF; and means for setting said unit ON auxiliary system threshold value when the status of said unit is ON.