Vehicle Torque Control During Tip-In Lash Transition
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Solution Overview
Problem
Existing engine control methods during vehicle acceleration following deceleration often result in poor driveability due to transmission or driveline gear lash issues, leading to clunk and increased response delay, which can be exacerbated by rate limiting torque changes.
Innovation Solution
A vehicle control method that coordinates throttle and ignition timing adjustments to manage engine torque during driver tip-in, retarding ignition timing and advancing spark angle to rapidly provide output torque once the driveline torque has transitioned past the lash zone, thereby reducing clunk without significantly increasing response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If rate limiting torque changes is applied to reduce clunk, then transmission lash impact is reduced, but engine response delay increases
Solution Approach 1:
The system performs preliminary action by pre-charging the intake manifold and cylinders with airflow before the driver tip-in event. This is achieved by coordinating throttle and ignition timing adjustments in advance, so that when the transition through the lash zone is complete, a more rapid torque increase is possible without excessive response delay
Solution Approach 2:
The system changes parameters by coordinating multiple torque actuators (throttle and ignition timing) during driver tip-in. By retarding ignition timing while adjusting engine airflow, the system enables a more rapid torque increase after transitioning through the lash zone, effectively increasing the rate of torque change when needed
2Object-affected harmful factors
If greater torque increase limitation is applied to reduce clunk, then transmission lash impact is reduced, but response delay increases
Solution Approach 1:
The system applies dynamics by making the torque actuator adjustments conditional and time-dependent. The coordination of throttle and ignition timing adjustments occurs specifically during the transition period through the lash zone, allowing the system to dynamically adapt the torque increase rate based on the driveline state
Solution Approach 2:
The system performs preliminary action by pre-charging the intake manifold and cylinders with airflow before the driver tip-in event. This is achieved by coordinating throttle and ignition timing adjustments in advance, so that when the transition through the lash zone is complete, a more rapid torque increase is possible without excessive response delay
Data Source
AI summary
A vehicle control method for a vehicle having an internal combustion engine coupled to a torque converter is described. In one embodiment, the engine air flow and spark are adjusted to control torque converter operation. The method can improve vehicle response to driver accelerator commands.