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AssigneeGeneral Motors Corporation
InventorsWilliam Leonard Aldrich III, Glenn P. O'Connell, Klaus J. Stutzer, Michael Lee Velliky
Estimating the term…
A control system and method maintains a constant engine idle speed during a garage shift of an automatic transmission-equipped vehicle with a torque converter. An engine control module or other processor identifies when transmission input clutch fill occurs. The engine control module increases engine output based on the transmission input clutch fill and before a decrease in engine idle speed occurs. The engine control module latches a turbine speed and a speed ratio (turbine speed/engine speed). The engine control module declares transmission input clutch fill if the latched turbine speed minus a current turbine speed is greater than the first calibration constant or if the latched speed ratio minus a current speed ratio is greater than the second calibration constant. The engine control module increases the engine output after waiting a first time delay after the transmission clutch fill.
A method for maintaining a constant engine idle speed during a garage shift of an automatic transmission with a torque converter, comprising:
A control system for maintaining a constant engine idle speed during a garage shift of an automatic transmission with a torque converter, comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
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Introducing closed-loop corrections: for idling
Controlling combustion engines
Term end not estimated
The present invention relates to automatic transmissions for vehicles, and more particularly to control systems for adjusting engine idle speed in a vehicle including an automatic transmission with a torque converter.
Vehicles such as automobiles, trucks, etc., typically include an internal combustion engine that is coupled by a hydraulic torque converter to an automatic transmission. The hydraulic torque converter includes a housing, a turbine, a stator and a pump. The housing is bolted to the flywheel of the engine. The housing rotates at the same speed as the engine. The pump includes fins that are attached to the housing. The fluid is directed by the fins radially outwardly into fins on the turbine, which causes the turbine to spin. The turbine is connected to the transmission. As a result, the hydraulic torque converter transfers engine torque to the transmission.
An engine control module (ECM) controls the internal combustion engine and modifies engine idle speed. The ECM modifies engine idle speed using idle air control (IAC), electronic throttle control (ETC), or other similar functions. The ECM typically receives the following control inputs: engine speed, transmission input speed, transmission temperature, transmission gear selector position, and vehicle speed. The transmission input speed is equal to a turbine speed of the torque converter.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 illustrates an uncompensated garage shift according to the prior art;
FIG. 2 is a functional block diagram of an engine control module (ECM) according to the present invention for compensating garage shifts to provide a constant engine idle speed;
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
The present invention detects transmission input clutch fill and performs engine idle speed compensation to provide a constant engine idle during the garage shift. In contrast to closed-loop feedback systems that compensate after engine idle speed decreases, the present invention anticipates a reduction in the engine idle speed before it occurs and provides compensation. As a result, engine idle quality is dramatically improved. While the transmission clutch fill detection and engine idle compensation will be described in conjunction with the engine control module (ECM), the present invention can be performed by one or more other vehicle processors.
Referring now to FIG. 2, an engine control module 50 is linked to an engine 52 and a transmission 54 with a torque converter. The engine control module 50 receives the following inputs from the engine 52 and the transmission 54: engine speed SE, transmission input speed ST, transmission temperature TT, transmission gear selector position GEAR, and vehicle speed SV.