SUB-IDLE DOWNSHIFT CONTROL OF A TRANSMISSION

摘要

A method is provided for use in a vehicle. The vehicle includes a transmission, a turbocharger, a transmission control module (TCM), an engine, and an engine control module (ECM). The engine includes a crankshaft that rotates at an engine speed and the turbocharger includes a turbine that rotates at a turbine speed. The method includes requesting a downshift of the transmission from an off-going gear ratio to an on-coming gear ratio. The turbine is rotating at an off-going turbine speed at the off-going gear ratio and the turbine is configured to rotate at an on-coming turbine speed at the on-coming gear ratio, greater than the off-going gear speed. A determination is made that the requested downshift is a powerdown low-throttle shift. An engine speed request value is then transmitted from the TCM to the ECM. The transmitted engine speed request value is at least equal to the on-coming gear speed.

主权项

1. A method for use in a vehicle having a transmission, a turbocharger, a transmission control module (TCM), an engine, and an engine control module (ECM), wherein the engine includes a crankshaft that rotates at an engine speed and the turbocharger includes a turbine that rotates at a turbine speed, the method comprising:
requesting a downshift of the transmission from an off-going gear ratio to an on-coming gear ratio; wherein the turbine is rotating at an off-going turbine speed at the off-going gear ratio and the turbine is configured to rotate at an on-coming turbine speed at the on-coming gear ratio, greater than the off-going turbine speed; determining the requested downshift is a powerdown low-throttle (PDLT) shift; and transmitting an engine speed request value from the TCM to the ECM; wherein the transmitted engine speed request value is at least equal to the on-coming gear speed.