Shift Control Apparatus for Exhaust Supercharger Deceleration
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Solution Overview
Problem
Existing shift control systems for vehicles with exhaust superchargers fail to effectively manage deceleration delays, leading to unnatural engine brake behavior and reduced driver satisfaction due to delayed torque reduction and ineffective engine braking.
Innovation Solution
A shift control apparatus that detects the driver's deceleration intention and adjusts the gear ratio transition speed to the minimum reduction gear ratio side by comparing actual and target engine torque, slowing the gear shift when the actual torque is higher than the target, thereby reducing sudden engine speed decreases and enhancing engine braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the accelerator pedal is returned to reduce engine torque, then deceleration intention is achieved, but torque-down is delayed due to supercharging pressure not decreasing, causing engine brake inefficacy
Solution Approach 1:
The control device delays the gear ratio transition to the minimum reduction gear ratio side when deceleration is detected, proactively preparing the transmission system to maintain engine speed within the engine brake effective range before torque-down completes, ensuring engine brake efficacy is preserved during the transient period
Solution Approach 2:
The gear ratio transition speed is dynamically adjusted based on the difference between target torque and actual torque. When this difference exceeds a threshold, the transition is slowed down; when it falls below the threshold, normal transition resumes, creating a dynamic adaptation to the torque-down process
2Productivity
If the gear ratio transitions quickly to the minimum reduction gear ratio side, then shift control efficiency is improved, but engine speed decreases suddenly, reducing engine brake effectiveness
Solution Approach 1:
The control system dynamically adjusts the gear ratio transition speed based on real-time torque difference. When the difference between target torque and actual torque exceeds a threshold, the transition to minimum reduction gear ratio is slowed down, preventing sudden engine speed drops that would reduce engine brake effectiveness
Solution Approach 2:
The control device continuously monitors the difference between target torque and actual torque, using this feedback to determine whether to delay the gear ratio transition. This closed-loop control ensures engine speed remains within the effective range for engine braking
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
This approach reduces the sense of unnaturalness felt by the driver by delaying the gear ratio transition to the minimum reduction gear ratio side, increasing engine brake effectiveness and improving deceleration smoothness.
Implementation Method 1
an engine (1) with an exhaust supercharger (4)
Implementation Method 2
a turbine continues rotating without stopping
Data Source
AI summary
A shift control apparatus for a vehicle which has an engine with an exhaust supercharger, and a transmission, if there is a deceleration intention of a driver, compares a target torque and an actual torque, and while the actual torque is higher than the target torque and a difference therebetween is greater than or equal to a predetermined threshold value, controls a speed at which to cause a gear ratio of the transmission to change to the target gear ratio to be slower than at a time of normal shift control.