Vehicle Control Device Gear Shift During Speed Limitation
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Solution Overview
Problem
Vehicle speed limitation systems (ASL) face a significant decrease in fuel efficiency when setting a relatively low vehicle speed upper limit, as they often maintain the vehicle in low-speed gear stages with large gear ratios, leading to poor drivability and increased fuel consumption.
Innovation Solution
A vehicle control device and method that includes a gear stage setting apparatus to shift the transmission to a higher gear stage with better fuel efficiency during engine output suppression, while maintaining the vehicle speed within the set upper limit, using a control unit connected to sensors and actuators to adjust engine output and gear shifts based on driving state and accelerator input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle speed upper limit is set to a relatively low speed and gear stage changes are prohibited during ASL execution, then the vehicle speed does not exceed the upper limit, but fuel efficiency decreases remarkably
Solution Approach 1:
The patent applies dynamics by making the gear stage changeable during ASL execution rather than fixed. The transmission control unit dynamically adjusts the gear stage based on vehicle speed and acceleration conditions, allowing the system to adapt to changing driving conditions while maintaining speed limitation. This resolves the contradiction by enabling the gear stage to transition from a static prohibited state to a dynamic adjustable state that optimizes fuel efficiency.
Solution Approach 2:
The patent changes the parameter of gear stage ratio by allowing upshifts during ASL execution under specific conditions. When the vehicle speed is below the upper limit by a predetermined value or more and acceleration is below a threshold, the transmission shifts to a higher gear stage with a smaller gear ratio. This parameter change enables better fuel efficiency while still maintaining the speed limitation function.
2Use of energy by moving object
If the gear stage is shifted up to a higher speed side gear stage during engine output suppression, then fuel efficiency improves, but vehicle speed control becomes more complex
Solution Approach 1:
The patent implements feedback control by continuously monitoring vehicle speed, acceleration, and gear stage conditions to determine when upshifts should occur during ASL execution. The transmission control unit uses feedback from the vehicle speed detection unit and acceleration information to make intelligent decisions about gear stage changes. This feedback mechanism manages control complexity by using simple, rule-based decision logic rather than complex algorithms.
Solution Approach 2:
The patent applies preliminary action by setting predetermined thresholds and conditions for upshift decisions before they are needed. The system pre-defines the conditions under which upshifts should occur (vehicle speed below upper limit by predetermined value, acceleration below threshold), allowing the control unit to make immediate decisions without complex real-time calculations. This reduces control complexity by preparing decision criteria in advance.
Data Source
AI summary
Even if an adjustable speed limitation function (ASL) sets a vehicle speed upper limit to a relatively low vehicle speed, a control unit 10 is configured to, in order to suppress the problem of a decrease in fuel efficiency while the ASL is executing the vehicle speed limitation, suppress an output of an engine 2 so that the vehicle speed does not exceed the vehicle speed upper limit, and cause a gear stage of an automatic transmission 3 to be shifted up to a higher speed side gear stage having higher fuel efficiency than a gear stage that is set based on the driving state of a vehicle 1, when a deviation between the vehicle speed detected by a vehicle speed sensor 21 and the vehicle speed upper limit that is set by a vehicle speed upper limit setting switch 24 becomes less than a predetermined threshold.