Transmission Ratio Control for Smooth Vehicle Reacceleration

Solution Overview

Problem

Existing vehicle control systems may downshift during reacceleration after detecting a deceleration factor, leading to uncomfortable acceleration and potential misperception of deceleration factors, causing discomfort to the driver.

Innovation Solution

The vehicle maintains the current speed ratio when a deceleration factor is detected and stepwise changes to a lower speed ratio only upon a driver-initiated deceleration request, ensuring smooth reacceleration and avoiding unnecessary changes in speed ratio when no actual deceleration factor is present.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the transmission speed ratio is changed to the lower speed side when a deceleration factor is detected, then the vehicle is prepared for subsequent reacceleration, but the driver may feel discomfort due to increased deceleration when the deceleration factor is erroneously perceived

Engineering Contradiction:

Improvereacceleration readinessVSAvoiddriver discomfort

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The transmission speed ratio is changed to the lower speed side in advance when a deceleration factor is detected, preparing the vehicle for subsequent reacceleration. This preliminary action ensures that when the driver requests reacceleration, the vehicle can respond more effectively without needing additional downshifts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors whether the detected deceleration factor is still present or has disappeared. When the deceleration factor disappears, the system provides feedback by maintaining the current speed ratio to prevent unnecessary deceleration and driver discomfort, while still being ready for reacceleration requests.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If the transmission speed ratio is maintained when a deceleration factor is detected, then driver discomfort is avoided during erroneous perception, but the vehicle cannot be smoothly accelerated during reacceleration

Engineering Contradiction:

Improvedriver discomfortVSAvoidacceleration smoothness

Core Design Contradiction:

Object-affected harmful factorsVSSpeed

Solution Approach 1:

The transmission speed ratio is changed to the lower speed side in advance when a deceleration factor is detected, preparing the vehicle for subsequent reacceleration. This preliminary action ensures that when the driver requests reacceleration, the vehicle can respond more effectively without needing additional downshifts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the transmission speed ratio based on the presence or disappearance of the deceleration factor and driver input. When the deceleration factor disappears and the driver requests acceleration, the system transitions from maintaining the current ratio to allowing downshifts, providing smooth and responsive acceleration.

Inventive Principle:

Principle #15Dynamics

3Speed

If the transmission downshifts during reacceleration after deceleration factor detection, then the vehicle responds to acceleration demand, but the acceleration feels unnatural and uncomfortable to the driver

Engineering Contradiction:

Improveacceleration responseVSAvoidacceleration smoothness

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The transmission speed ratio is changed to the lower speed side in advance when a deceleration factor is detected, preparing the vehicle for subsequent reacceleration. This preliminary action ensures that when the driver requests reacceleration, the vehicle can respond more effectively without needing additional downshifts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system maintains the prepared lower speed ratio continuously after the deceleration factor disappears, ensuring that the transmission is already in the optimal state for acceleration. This eliminates interruptions and ensures continuous, smooth acceleration when the driver demands it.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS11215278B2Vehicle and method for controlling same

Publication Date: 2022.01.04 TOYOTA JIDOSHA KK

AI summary

The disclosure provides a vehicle and a method for controlling the vehicle. The vehicle includes: an engine; a transmission configured to transmit power from the engine to drive wheels; a deceleration factor detection device configured to detect a deceleration factor that is present ahead of the vehicle; and an electronic control unit configured to maintain a speed ratio of the transmission as a current speed ratio on condition that the deceleration factor is detected by the deceleration factor detection device, and change the speed ratio stepwise to a lower speed side than the current speed ratio and maintain the changed speed ratio, in response to a deceleration request from a driver.