Automotive powertrain control
AssigneeGeneral Motors Corporation
InventorsJoseph Mark Tolkacz, Eric Hans Gassenfeit
Life of this patent
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Abstract
Engine speed control during garage shift maneuvers of a transmission coupled, via a transmission input shaft, to a driven turbine of a hydrodynamic converter, the driven turbine fluidically coupled to a driving pump of the converter, the pump coupled to an engine output shaft, wherein engine output torque is controlled in response to a deviation in turbine acceleration away from a target turbine acceleration, to minimize rate of change in turbine acceleration (jerk) during the garage shift maneuver, so as to reject engine torque load changes that may result in undesirable engine speed variation.
Claims12
A method for controlling speed of an engine coupled, via a hydrodynamic converter, to an automatic transmission, the hydrodynamic converter having a pump rotating with an engine output shaft and a turbine rotating with a transmission input shaft, the transmission having driven and undriven states, the method comprising the steps of:
- sensing a request for transition between driven and undriven transmission states;
- determining actual change in turbine speed upon sensing the request;
- providing a target turbine speed change value;
- calculating an acceleration error representing a difference between the target turbine speed change and the actual turbine speed change;
- generating an engine output torque change as a function of the acceleration error to minimize the error;
- and
- varying engine output torque in accordance with the generated engine output torque change to control engine speed during the transition between driven and undriven transmission states.
In a control system for an automotive powertrain including an engine having an output shaft, a transmission having an input shaft, and a fluidic torque converter for coupling the engine to the transmission, the torque converter having a pump mechanically linked to the engine output shaft and a turbine mechanically linked to the transmission input shaft and fluidically linked to the pump, a method for varying engine output torque during a garage shift maneuver between undriven and driven transmission states to reject engine torque load changes so as to maintain a substantially constant engine speed throughout the garage shift maneuver, comprising the steps of:
- detecting initiation of a garage shift maneuver between undriven and driven transmission states;
- sampling, during the garage shift maneuver, a turbine speed signal indicating rate of rotation of the turbine;
- calculating change in turbine speed during the garage shift maneuver;
- calculating turbine acceleration error as a difference between the calculated turbine speed change and a target turbine speed change;
- determining an engine output torque change as a function of the calculated turbine acceleration error;
- and
- varying engine output torque during the garage shift maneuver in accordance with the determined engine output torque change.
Dependencies are inferred from the claim text.