Vehicle Control Device Engine Speed Transition
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Solution Overview
Problem
Existing vehicle control systems do not effectively manage the transition from hybrid traveling mode to engine traveling mode without causing driver discomfort due to the operating sound of the internal combustion engine.
Innovation Solution
A control device that shifts from hybrid traveling mode to engine traveling mode by increasing the internal combustion engine's rotational speed with vehicle speed, then decreasing it to a lower speed, and using a calculated decrease rate to smoothly transition to engine traveling mode, thereby minimizing discomfort from engine sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the traveling mode is shifted from hybrid traveling mode to engine traveling mode, then the vehicle can travel by engine power, but the driver experiences discomfort due to engine operating sound
Solution Approach 1:
The control device performs preliminary actions by increasing the engine rotational speed before the mode transition, then decreasing it to a lower speed, and calculating the decrease rate. This preliminary preparation of the rotational speed profile ensures that when the transition to engine traveling mode occurs, the engine sound changes smoothly, preventing driver discomfort.
Solution Approach 2:
The system dynamically adjusts the engine rotational speed based on the transition requirements. The control device calculates the decrease rate of rotational speed and applies it dynamically during the mode transition, making the engine sound profile adaptive and smooth rather than abrupt, thereby resolving the contradiction between maintaining traveling capability and reducing harmful sound effects.
2Power
If the engine rotational speed is increased in accordance with vehicle speed increase, then the engine can provide sufficient power, but the engine operating sound becomes more noticeable
Solution Approach 1:
The control device implements periodic action by increasing the engine rotational speed in stages - first increasing with vehicle speed, then decreasing to a lower speed, and maintaining it with a calculated decrease rate. This periodic adjustment pattern allows the engine to provide sufficient power while managing the operating sound levels through controlled speed variations.
Solution Approach 2:
The system changes the engine rotational speed parameter dynamically - increasing it to maintain power output, then decreasing it to reduce sound, and calculating the optimal decrease rate. This parameter change strategy resolves the contradiction by adjusting the rotational speed to balance power requirements with sound comfort during mode transitions.
Data Source
AI summary
A control device includes an internal combustion engine control unit configured to control an internal combustion engine. The internal combustion engine control unit is configured to, in a case where a first traveling mode, increase a rotational speed of the internal combustion engine in accordance with an increase in a speed of a vehicle and when the rotational speed reaches a predetermined first rotational speed, decrease the rotational speed to a second rotational speed lower than the first rotational speed, calculate a decrease rate of the rotational speed of the internal combustion engine per unit time when the rotational speed is decreased from the first rotational speed to the second rotational speed, and in a case where the traveling mode setting unit shifts from the first traveling mode to the second traveling mode, decrease the rotational speed of the internal combustion engine based on the decrease rate.