Vehicle Inertia Control via Deceleration Threshold

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Solution Overview

Problem

Conventional vehicle control systems experience deceleration shocks and reduced fuel efficiency due to frequent switching between clutch-on and clutch-off states during inertia operation, affecting drivability and fuel consumption.

Innovation Solution

A vehicle control device that calculates the actual deceleration degree and compares it to threshold values to determine whether to start or maintain inertia operation, preventing frequent switching and optimizing deceleration behavior based on driver input and vehicle state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the clutch device is frequently switched between on and off states during inertia operation, then the fuel efficiency is improved, but the drivability is degraded due to deceleration shocks

Engineering Contradiction:
Improvefuel efficiencyVSAvoiddrivability
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The control device continuously monitors the actual deceleration degree of the vehicle and compares it with a threshold value. Based on this feedback comparison, the system intelligently determines whether to maintain or terminate inertia operation, thereby avoiding frequent clutch switching while still achieving fuel efficiency improvements.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the operational parameter (clutch state) based on the deceleration degree parameter. By monitoring deceleration degree and comparing it with a threshold, the system determines the appropriate clutch state to maintain, thus reducing frequent switching while preserving fuel efficiency benefits.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the inertia operation state is immediately terminated when brake or accelerator operation is performed, then the vehicle responds quickly to driver input, but deceleration shocks occur due to sudden clutch switching

Engineering Contradiction:
Improveresponse speedVSAvoiddeceleration shock
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The system uses feedback from the deceleration degree sensor to determine whether to terminate inertia operation. Only when the actual deceleration degree exceeds the threshold value does the system terminate the operation, ensuring quick response to genuine driver intent while avoiding shocks from unnecessary clutch switching.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control device performs preliminary assessment by comparing the actual deceleration degree with the threshold value before terminating inertia operation. This preliminary check ensures that clutch switching occurs only when truly necessary, preventing deceleration shocks while maintaining responsive vehicle control.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If the clutch device is kept in shut-off state during deceleration, then the fuel consumption is reduced, but the deceleration behavior becomes inconsistent with driver expectations

Engineering Contradiction:
Improvefuel consumptionVSAvoiddeceleration behavior consistency
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system continuously monitors deceleration degree and compares it with the threshold to determine whether to maintain clutch shut-off state. This feedback mechanism ensures that fuel-saving inertia operation is maintained only when deceleration behavior matches driver expectations, while still achieving fuel consumption reduction.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The clutch state parameter is changed based on the deceleration degree parameter. By setting the clutch shut-off condition based on deceleration degree comparison with threshold, the system achieves fuel consumption reduction while maintaining consistent deceleration behavior that aligns with driver intent.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3954917B1Vehicle control device for controlling inertia operation of vehicle
Publication Date: 2023.05.03 DENSO CORP
  • EP3954917B1 patent drawingFigure 1
  • EP3954917B1 patent drawingFigure 2~3
  • EP3954917B1 patent drawingFigure 4~5

AI summary

A vehicle control device is configured to be applied to a vehicle including an engine configured to serve as a motive power source and a clutch device provided on a power transmission path leading to an output shaft of the engine. The vehicle control device puts the clutch device into a shut-off state to put the vehicle into an inertia operation state in response to a predetermined executing condition being met, and puts the clutch device into a connection state to terminate the inertia operation state in response to a predetermined terminating condition being met during inertia operation. The vehicle control device comprises: a deceleration degree calculating means configured to calculate an actual deceleration degree that is a deceleration degree of the vehicle in a vehicle deceleration state during non-inertia operation; a determination means configured to determine whether the actual deceleration degree calculated by the deceleration degree calculating means is less than a threshold value defined on the basis of a deceleration degree of the vehicle in such a state that no accelerator operation is performed and the clutch device is connected; and an operation control means configured to start the inertia operation if the actual deceleration degree is determined to be less than the threshold value, and maintain the non-inertia operation if the actual deceleration degree is determined to be greater than the threshold value.