Series Hybrid Drive Control Optimizing Efficiency and Acceleration
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Solution Overview
Problem
Conventional series hybrid vehicle control systems fail to provide an acceleration feeling consistent with engine speed changes and suffer from decreased power generation and engine efficiency, particularly when vehicle speed or battery charging levels are low.
Innovation Solution
A drive control device for series hybrid vehicles that includes an accelerator pedal level detector, a charging level detector, and a controller to adjust engine speed and torque based on accelerator pedal input, optimizing power generation efficiency and battery charging by shifting engine operating points according to vehicle speed and battery state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fixed-point operation is used to maintain maximum engine efficiency, then power generation efficiency is improved, but engine sound does not correspond to vehicle speed changes causing strange driving feeling
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-point engine operation to dynamic engine speed control that adapts to vehicle conditions. The controller adjusts engine speed based on vehicle speed and accelerator pedal opening degree, allowing the engine to operate at varying speeds rather than a fixed point, thereby maintaining efficiency while providing natural acceleration feeling and corresponding engine sound.
Solution Approach 2:
The patent changes the operating parameters of the engine from fixed values to variable values. By adjusting engine speed and torque as variables based on vehicle conditions (vehicle speed, accelerator pedal opening), the system maintains power generation efficiency while enabling engine sound to reflect acceleration states, improving driving feeling.
2Ease of operation
If completely associated operation is used to match accelerator pedal opening with engine speed, then acceleration feeling is improved, but power generation efficiency decreases due to prolonged power-consumption balance time
Solution Approach 1:
The system uses dynamic control to adjust engine operation based on real-time vehicle conditions. Rather than maintaining complete association between accelerator pedal and engine speed, the controller dynamically adjusts engine parameters to balance acceleration feeling with power generation efficiency, operating at optimal points during charging phases.
Solution Approach 2:
The patent implements periodic action through alternating operation modes: power generation priority mode during charging phases and acceleration priority mode during discharge phases. This periodic switching between modes allows the system to maintain both good acceleration feeling and high power generation efficiency at different times.
3Loss of energy
If engine operates at maximum efficiency point, then power generation efficiency is improved, but engine efficiency decreases when vehicle is stopping or fully accelerated
Solution Approach 1:
The patent changes engine operating parameters based on vehicle state. During stopping or full acceleration conditions, the controller adjusts engine speed and torque parameters to prevent efficiency degradation, ensuring the engine operates within efficient ranges even during transient states.
Solution Approach 2:
The system uses feedback from vehicle speed sensors and accelerator pedal position sensors to continuously monitor operating conditions. This feedback enables the controller to adjust engine parameters in real-time, maintaining both power generation efficiency and engine efficiency during various vehicle states including stopping and full acceleration.
Data Source
AI summary
A hybrid system includes a hybrid controller which controls the speed and torque of an engine based on the operated level of an accelerator pedal within a first range where the power generation efficiency of the system becomes equal to or higher than a preset power generation efficiency to allow the engine to operate at an engine operating point when the SOC detected by an SOC sensor is equal to or higher than an HEV low SOC, and which controls the speed and torque of the engine based on the operated level of the accelerator pedal within a second range where the power generated by a power generator motor becomes larger than that of the first range to allow the engine to operate at the engine operating point when the SOC detected by the SOC sensor is lower than the HEV low SOC.