Patent ID: 8874331

Claim:
An idle throttle variation unit for an automobile comprising: an engine having an engine output speed; an engine sensor configured to measure the engine output speed and to generate engine output speed data corresponding to the measured engine output speed; a torque converter coupled to the engine; a transmission coupled to the torque converter and having a transmission input speed; a transmission sensor configured to measure the transmission input speed and to generate transmission input speed data corresponding to the transmission input speed; a throttle coupled to the engine and configured to output an airflow to the engine during a current idle operation of the engine; a memory configured to store throttle airflow compensation values for torque converter loads corresponding to torque converter speed ratio values for an idle operation of the engine; and an engine control unit coupled to at least the engine sensor, the transmission sensor, and the memory, the engine control unit configured to: determine a torque converter speed ratio based on the engine output speed data and the transmission input speed data, determine a total target throttle airflow for the current idle operation of the engine based on the determined torque converter speed ratio and the stored throttle airflow compensation values for the torque converter loads, and control the airflow outputted by the throttle to the engine during the current idle operation of the engine based on the determined total target throttle airflow.