Hybrid Vehicle Control Device Engine Speed Rise Rate
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Solution Overview
Problem
Conventional vehicle control systems for hybrid vehicles with internal combustion engines and rotary electric machines experience delayed rotational speed increase during high-speed operation, leading to uncomfortable acceleration performance due to inefficient power distribution and torque management.
Innovation Solution
A vehicle control apparatus that dynamically adjusts the rise rate of the internal combustion engine's rotational speed based on vehicle speed and acceleration requests, using a hybrid ECU to set a higher rise rate during high-speed running and adjust torque distribution to minimize fluctuations and improve acceleration feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal combustion engine is started by the rotary electric machine during high-speed vehicle operation, then the engine can be started, but the time for raising the rotational speed is delayed and acceleration performance deteriorates
Solution Approach 1:
The control device dynamically adjusts the rise rate of engine rotational speed based on vehicle operating conditions. During high-speed vehicle operation, the control device sets a higher rise rate for engine rotational speed compared to low-speed operation, enabling the engine to reach its target rotational speed faster and improve acceleration performance while maintaining reliable starting capability.
Solution Approach 2:
The control device changes the parameter of rotational speed rise rate according to vehicle speed and acceleration requests. By detecting vehicle speed and acceleration pedal operation, the control device selects appropriate rise rate values, increasing the rise rate during high-speed operation to prevent acceleration deterioration while ensuring reliable engine starting during low-speed operation.
2Device complexity
If a conventional rise rate is used during high-speed operation, then the system is simple to control, but the acceleration performance becomes uncomfortable for the driver
Solution Approach 1:
The control device implements dynamic adjustment of engine rotational speed rise rate based on real-time detection of vehicle speed and acceleration requests. This dynamic control strategy improves acceleration performance during high-speed operation without requiring complex hardware modifications, maintaining reasonable system complexity while enhancing driver comfort.
Solution Approach 2:
The control device uses feedback from vehicle speed sensors and acceleration pedal position sensors to determine the appropriate rise rate of engine rotational speed. This feedback mechanism enables the system to automatically adjust control parameters based on actual operating conditions, improving acceleration performance while keeping the control logic relatively simple through rule-based decision making.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enhances acceleration performance by rapidly increasing engine rotational speed during high-speed operations, reducing the impact of inertia torque on power distribution and improving the driver's acceleration feel by smoothing torque transmission to the drive wheels.
Implementation Method 1
a rotary electric machine... operative to rotate the output shaft of the internal combustion engine with the power of the rotary electric machine
Data Source
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Figure 3(a)~3(d)
AI summary
Disclosed is a vehicle control apparatus which can execute a start-up control for improving acceleration performance at the time of starting an internal combustion engine during the running of a hybrid vehicle. When a hybrid ECU determines that a predetermined time (T1) has not yet elapsed after termination of the start-up control of the engine (NO in Step (S12)), and that the hybrid vehicle is in a high speed, high load condition, but not in a warming-up state (YES in Step (S13)), the hybrid ECU sets a value Nupest2 larger than a value Nupest1, that is usually set as a maximum value Krmx of a rise rate of an engine rotational speed (Step (S 15)).