Vehicle Shift Control for Adaptive Neutral Switching Timing
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Solution Overview
Problem
Existing vehicle control devices may inadvertently switch to the neutral position more than necessary during traveling due to operation speed not accurately reflecting the need to cut off driving force, leading to erroneous switching and suboptimal response times.
Innovation Solution
A control device that adjusts the neutral position switching time based on the vehicle's driving force, setting a shorter time for higher driving forces and a longer time for lower driving forces to improve erroneous switching prevention and response performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the neutral position switching time is set to a fixed value based on operation element speed, then the switching control is simple, but the switching accuracy and response performance deteriorate due to erroneous switching during traveling
Solution Approach 1:
The patent applies dynamics by making the neutral position switching time variable rather than fixed. The control device dynamically adjusts the switching time based on real-time driving force conditions detected during vehicle operation. When high driving force is detected, a shorter switching time is applied for rapid response, while under low driving force conditions, a longer switching time prevents erroneous switching, thus resolving the contradiction between switching accuracy and response performance
Solution Approach 2:
The patent changes the parameter of neutral position switching time based on driving force magnitude. By monitoring driving force conditions and adjusting the switching time parameter accordingly, the system achieves both high switching accuracy (by preventing erroneous switching under low driving force) and fast response (by using shorter times under high driving force), while maintaining relatively simple control logic through clear parameter thresholds
2Speed
If the neutral position switching time is shortened for faster response, then the switching response performance improves, but erroneous switching increases during traveling
Solution Approach 1:
The system dynamically adapts the switching time parameter based on real-time driving force detection. During high driving force conditions when rapid neutral switching is needed, the system uses a shorter switching time for fast response. During low driving force conditions when erroneous switching is likely, the system automatically extends the switching time, thereby maintaining both fast response capability and high switching reliability without contradiction
Solution Approach 2:
The control device implements feedback by continuously monitoring driving force conditions and using this information to adjust the neutral position switching time. This closed-loop approach ensures that the switching time is optimized based on actual operating conditions, preventing erroneous switching while maintaining fast response when needed, thus resolving the reliability-speed contradiction
3Ease of operation
If the determination time is set based on operation speed to the brake position, then the control logic is simple, but the switching performance deteriorates when the operation speed to neutral position does not reflect the need to cut off driving force
Solution Approach 1:
The patent changes the basis for determining switching time from operation element speed alone to a composite parameter including driving force magnitude. This allows the system to maintain simple control logic through clear decision thresholds while dramatically improving switching efficiency by preventing erroneous neutral switching and enabling faster appropriate switching, thus resolving the contradiction between control simplicity and switching efficiency
Data Source
AI summary
The vehicle includes a power source, a power transmission device that transmits power from the power source to a drive wheel, and an operation device that is operated by a driver to an operation position corresponding to a shift position of the power transmission device. The control device of the vehicle includes a shift control unit that changes an N-position switching time from when the vehicle is operated to the neutral operation position until when the vehicle is switched to the neutral position based on the vehicle state. The shift control unit shortens the N-position switching time as compared with a case where the driving force of the drive wheel is large.