Hybrid Powertrain Controller Torque Redistribution for Engine Autostop
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Solution Overview
Problem
Hybrid vehicle powertrains face challenges in smoothly transitioning to electric motor-only operation during engine autostop, leading to perceivable torque disruptions that affect passenger comfort.
Innovation Solution
A controller is configured to manage the engine and electric motors by entering a deceleration fuel cut-off mode, increasing the first motor's torque to zero transmission input torque while decreasing the second motor's torque, maintaining constant total axle torque, thereby minimizing the perception of engine autostop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is turned off during certain operating conditions to achieve engine autostop, then fuel consumption is reduced, but torque disruption occurs that affects passenger comfort
Solution Approach 1:
The controller increases transmission input torque to zero before shutting off the engine, and pre-adjusts the second motor's torque to compensate for the upcoming torque disruption. This preliminary action ensures that when the engine stops, the total axle torque remains constant and passengers do not perceive any torque disruption.
Solution Approach 2:
The controller dynamically adjusts the torque parameters of the first and second motors during the engine autostop transition. Specifically, it increases the first motor's torque contribution and decreases the second motor's torque while maintaining constant total axle torque, thereby eliminating harmful torque disruptions during the energy-saving engine off-state.
2Use of energy by moving object
If the transmission input torque is increased to zero during engine autostop, then the engine can be shut off for energy saving, but the torque transition may cause passenger discomfort
Solution Approach 1:
The controller continuously monitors the torque output of both motors and the transmission input torque, dynamically adjusting the second motor's torque in response to changes in the first motor's torque. This feedback mechanism ensures that any torque disruptions are immediately compensated, maintaining passenger comfort while enabling energy-saving engine autostop operation.
Solution Approach 2:
Before the engine is shut off and transmission input torque reaches zero, the controller pre-adjusts the torque distribution between the two motors. This preliminary torque redistribution ensures a smooth transition that maintains passenger comfort while achieving the energy-saving goal of engine shutdown.
3Stability of the object's composition
If the torque of the second motor is decreased during the autostop procedure, then the first motor can compensate to maintain constant total axle torque, but the torque redistribution complicates the control system
Solution Approach 1:
The controller is designed to perform multiple functions: it manages normal engine operation, executes engine autostop procedures, and dynamically redistributes torque between the two motors. By integrating these functions into a single multi-functional control module, the patent manages control system complexity while maintaining constant total axle torque through coordinated torque adjustments.
Data Source
AI summary
A vehicle includes a first axle, a second axle, an engine having a crankshaft, a transmission having an input member that is operatively connected to the crankshaft and an output member that is operatively connected to the first axle, a first motor having a first rotor operatively connected to the crankshaft, a second motor having a second rotor that is operatively connected to the second axle, and a controller being operatively connected to the engine, the first motor, and the second motor. The controller is configured to selectively cause the engine to enter a deceleration fuel cut off mode, cause the transmission input torque to increase to zero, cause the torque of the second motor to decrease as the transmission input torque increases such that the sum of the first axle torque and the second axle torque remains substantially constant as the transmission input torque increases to zero.