Hybrid Powertrain Control for Imperceptible Engine Operation
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Solution Overview
Problem
Hybrid powertrain systems operating in electric vehicle mode at or near system limits can reduce customer satisfaction due to issues with engine startability and tip-in response.
Innovation Solution
A hybrid powertrain system with an internal combustion engine and electric machine mechanically coupled via a geartrain, where the engine operation is controlled to be imperceptible in the passenger compartment by determining specific speed/load regions and operating the engine at a preferred speed that is imperceptible, ensuring smooth and responsive torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hybrid powertrain operates in EV mode at or near system limits, then electric vehicle mode operation is enhanced, but engine startability and tip-in response are reduced
Solution Approach 1:
The control system performs preliminary action by pre-charging the energy storage device before EV mode operation is needed. The system determines when to charge the energy storage device in advance, ensuring sufficient charge is available before EV mode activation, thereby preventing engine startability issues and tip-in response problems that occur when operating at system limits
2Ease of operation
If the engine is operated to be imperceptible in the passenger compartment, then customer satisfaction is enhanced, but torque generation capability is reduced
Solution Approach 1:
The control system applies parameter changes by adjusting engine operating parameters (speed and load) to specific ranges that make engine operation imperceptible to passengers. The system determines speed/load regions where engine operation is quiet and smooth, then controls the engine to operate within those regions, maintaining customer satisfaction while still providing necessary torque generation capability through the hybrid powertrain system
Data Source
AI summary
A method for controlling a hybrid powertrain system includes determining an operator-selected mode and a charging mode for the energy storage device. A first speed/load region at which the internal combustion engine is in an OFF state is determined for the operator-selected mode and the charging mode for the energy storage device, wherein the first speed/load region is defined by output torque and vehicle speed. A second speed/load region includes a preferred speed that is selected for operating the internal combustion engine is determined for the operator-selected mode and the charging mode for the energy storage device. The preferred engine speed is substantially imperceptible in a passenger compartment of the vehicle. The internal combustion engine is operated at the preferred engine speed that is imperceptible in the passenger compartment when the output torque request and the present vehicle speed are within the second operating region.