Hybrid Drive Control Apparatus Engine Speed Torque Management
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Solution Overview
Problem
In hybrid electric vehicle drive control systems, maintaining engine speed within limits while ensuring sufficient drive torque and protecting batteries from overvoltage, overdischarge, and overcharge is challenging, as high engine speed can lead to reduced engine output and potential battery damage.
Innovation Solution
A drive control apparatus that calculates and manages engine speed and torque targets to prevent excessive engine speed, uses electrical power limits based on battery state, and controls motor generators to operate within power running or regenerating modes, ensuring the engine speed does not exceed an upper limit and that electrical power targets do not exceed battery charging or discharging limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine speed is prevented from becoming high, then the engine output is reduced, but the drive torque requested by the vehicle driver cannot be satisfied
Solution Approach 1:
The patent combines the engine output with motor generator outputs to achieve the required drive torque. When engine speed is limited, the motor generators compensate for the reduced engine output, ensuring the total drive torque meets driver demands while keeping engine speed within safe limits.
Solution Approach 2:
The motor generators act as intermediaries between the limited engine output and the required drive torque. They bridge the gap by providing additional power when engine speed is constrained, allowing the system to satisfy driver torque requests without exceeding engine speed limits.
2Power
If the motor generators are controlled to operate in power running mode or regenerating mode to provide drive torque, then the drive torque can be satisfied, but overvoltage during battery charge/discharge may occur
Solution Approach 1:
The control system continuously monitors battery voltage and adjusts motor generator operation accordingly. When battery voltage approaches dangerous levels during charging or discharging, the feedback mechanism reduces or stops power transfer to/from the battery, preventing overvoltage conditions while still providing necessary drive torque through engine contribution.
3Reliability
If the engine speed is kept lower to prevent overvoltage, then battery protection is improved, but the engine output becomes insufficient
Solution Approach 1:
The system dynamically changes operational parameters by adjusting the contribution ratio between engine and motor generators based on battery state. When battery voltage is high, the system shifts toward engine-driven operation with reduced motor generator charging, protecting the battery while maintaining sufficient total power output through parameter optimization.
Data Source
AI summary
An arrangement which prevents excessive engine speed, satisfies a driver's requested torque and protects a battery from overvoltage. A control apparatus provides a torque control to a hybrid electric vehicle, and calculates an engine speed final target so that an engine speed temporary target does not exceed an upper limit. In addition, the control recalculates an engine operating point target based on the calculated engine speed final target, and calculates an engine power final target based on the recalculated engine operating point target. An electrical power target is calculated and may not exceed an upper limit for battery charging and an upper limit for battery discharging. Engine torque is controlled based on the calculated engine operating point target (especially the engine torque final target). Motor generators are controlled to operate based on the calculated engine operating point target and electrical power target.