Hybrid Engine Idle Speed Control via Electric Motor Torque Split
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Solution Overview
Problem
Conventional engine idle speed control in hybrid electric vehicles is inefficient due to the need for quick output responses, which leads to unstable speed control and inefficient engine operation.
Innovation Solution
An apparatus that uses an electric motor connected to the engine to control idle speed by determining engine target speed and torque, splitting control torque between the electric motor and engine, and adjusting torque compensation to maintain stable engine speed, thereby improving speed control performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional idle speed control is performed by controlling air volume, fuel volume, and ignition timing to achieve quick output response, then speed control responsiveness is improved, but engine operating efficiency deteriorates
Solution Approach 1:
The patent introduces an electric motor as an intermediary device to assist the engine in idle speed control. The electric motor provides quick torque response to compensate for speed fluctuations, allowing the engine to operate at higher efficiency points while maintaining stable idle speed. This mediator approach resolves the contradiction by decoupling the speed control function from direct engine parameter adjustments.
Solution Approach 2:
The patent merges the idle speed control function with the electric motor's torque output capability. By combining the engine's steady-state efficiency characteristics with the electric motor's dynamic response characteristics, the system achieves both quick responsiveness and high operating efficiency simultaneously during idle conditions.
2Stability of the object's composition
If engine idle speed control is performed by adjusting air volume, fuel volume, and ignition timing, then engine speed stability is improved, but system complexity increases
Solution Approach 1:
The electric motor serves as a mediator that simplifies the control system architecture. Instead of relying solely on complex adjustments of multiple engine parameters (air volume, fuel volume, ignition timing), the system uses the electric motor's torque output as a direct and simple control means to maintain engine speed stability, thereby reducing overall system complexity.
3Speed
If the electric motor assumes full control torque during idle speed control, then speed control performance is improved, but the engine operates inefficiently under increased friction loads
Solution Approach 1:
The patent applies partial action by having the electric motor provide only the necessary compensation torque rather than full control torque. The control system calculates the required compensation torque based on the difference between target and actual engine speed, allowing the electric motor to intervene only when needed. This partial intervention maintains speed control performance while minimizing impact on engine operating efficiency.
Solution Approach 2:
The system dynamically changes the torque distribution parameter between the electric motor and engine based on operating conditions. When friction loads increase, the control algorithm adjusts the torque split to optimize engine efficiency while maintaining adequate speed control performance, rather than maintaining a fixed torque allocation strategy.
Data Source
AI summary
An apparatus for controlling engine idling of a hybrid electric vehicle having an engine, an electric motor and a driving motor includes: an engine target speed determination part to determine an engine target speed when an engine idle speed control is requested; an engine target torque determination part to determine an engine target torque when the engine idle speed control is requested; a speed control part to determine a control torque for maintaining an engine speed at a predetermined speed based on a difference value between the engine target speed and an engine actual speed; a power split part to determine an output torque of the electric motor and an engine compensation torque of the engine based the control torque; and a final engine torque determination part to sum the engine compensation torque and the engine target torque to determine a final engine torque.