Driving Source Speed Suppression for Smoother Vehicle Acceleration
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Solution Overview
Problem
Existing vehicle control systems that limit excessive rotational speed of the driving source can deteriorate the driving feeling by causing large output fluctuations or poor acceleration, leading to a compromised driving experience.
Innovation Solution
A vehicle control method that includes a control circuitry and actuator system to suppress the output power of the driving source based on a preset upper threshold, with the suppression amount adjusted according to the excess time period and degree of rotational speed exceeding the threshold, thereby maintaining optimal driving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If output suppression of the engine is started when the rotational speed is around the excessive rotational speed, then the excessive rotational speed is limited, but the output fluctuation width becomes large and driving feeling deteriorates
Solution Approach 1:
The suppression start rotational speed is dynamically adjusted based on the rotational speed change rate. When the rotational speed is increasing rapidly, the suppression start rotational speed is set higher, and when the increase is gradual, it is set lower. This dynamic adjustment allows the suppression to start at the appropriate moment, limiting excessive rotational speed while minimizing output fluctuations that would deteriorate driving feeling.
Solution Approach 2:
The control system changes the suppression start rotational speed parameter based on the rotational speed change rate. By making this parameter variable rather than fixed, the system can adapt to different driving conditions and rotational speed trajectories, achieving both rotational speed limitation and smooth output suppression that maintains driving feeling.
2Reliability
If the output suppression of the engine is started when the rotational speed is lower than the excessive rotational speed, then the excessive rotational speed is limited, but the acceleration feeling of the vehicle deteriorates
Solution Approach 1:
The suppression start rotational speed is dynamically determined based on the current rotational speed and its change rate. This dynamic approach ensures that suppression begins at the optimal moment - high enough to maintain acceleration feeling but low enough to prevent excessive rotational speed - adapting continuously to the engine's operational state.
3Reliability
If the rotational speed of the driving source is limited to a predetermined excessive rotational speed or less, then the excessive rotational speed is prevented, but the output power suppression causes large fluctuations and deteriorates driving feeling
Solution Approach 1:
The control system continuously monitors the rotational speed and its change rate, using this feedback to dynamically adjust the suppression start rotational speed. This feedback mechanism ensures that output power suppression is timed appropriately, preventing large fluctuations and maintaining driving feeling while still limiting excessive rotational speed.
Data Source
AI summary
A vehicle includes: a driving source; a rotation sensor that detects a rotational speed of the driving source; control circuitry; and an actuator that operates the driving source. When the rotational speed of the driving source has exceeded a preset upper threshold, the control circuitry executes suppression control that suppressed an output power of the driving source in comparison with before the rotational speed of the driving source exceeds the upper threshold. In the suppression control, the control circuitry gives to the actuator a command that makes the output power of the driving source suppressed in comparison with before the suppression control is executed, in accordance with an excess degree set in relation to an excess time period that is a time period in which the rotational speed of the driving source has exceeded the upper threshold.