Accelerator Pedal Click Position Compensation

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Solution Overview

Problem

Variations in mechanical precision of the click mechanism in accelerator pedals lead to inconsistent detection of the click position, resulting in unpredictable kick-down performance of automatic transmissions, causing either premature or delayed kick-down, which affects driver expectations and drivability.

Innovation Solution

A vehicle shift controller that integrates stay time of the accelerator pedal within a predetermined stroke range to calculate a click stroke, updating the control stroke relationship to ensure accurate kick-down performance, even with variations in click position precision, by using stay time integrating and click stroke calculating means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed kick-down stroke is set based on a predetermined voltage threshold, then the kick-down control is simple to implement, but variation in click mechanism precision causes inconsistent kick-down timing

Engineering Contradiction:

Improvekick-down controlVSAvoidkick-down timing consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the parameter used for kick-down detection from a fixed voltage threshold to a dynamic threshold based on the detected click position. The ECU detects the actual click position through the stroke sensor and sets the kick-down stroke accordingly, allowing the system to adapt to variations in click mechanism precision while maintaining simple control logic.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the kick-down stroke is set lower to prevent premature kick-down, then false early kick-down is avoided, but hysteresis for upshift and downshift becomes insufficient

Engineering Contradiction:

Improvekick-down timing accuracyVSAvoiddrivability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent makes the kick-down stroke dynamic rather than fixed. The kick-down stroke is determined based on the detected click position, allowing the system to automatically adjust the threshold to maintain appropriate hysteresis while preventing premature kick-down. This dynamic adjustment preserves drivability by ensuring sufficient hysteresis for smooth shift transitions.

Inventive Principle:

Principle #15Dynamics

3Reliability

If the kick-down stroke is set higher to ensure proper click position detection, then premature kick-down is prevented, but delayed kick-down occurs when click position varies

Engineering Contradiction:

Improvekick-down timing accuracyVSAvoidkick-down response time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements feedback by continuously monitoring the actual click position through the stroke sensor and using this information to dynamically adjust the kick-down stroke threshold. This feedback mechanism ensures that the kick-down timing accurately reflects the driver's intent regardless of variations in click mechanism precision, preventing both premature and delayed kick-down.

Inventive Principle:

Principle #23Feedback

4Reliability

If variation in click mechanism precision is compensated by lowering the kick-down stroke, then consistent kick-down timing is achieved, but the vertical widths of shift lines become narrower

Engineering Contradiction:

Improvekick-down timing consistencyVSAvoidshift map hysteresis

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary detection of the click position before setting the kick-down threshold. By detecting the actual click position first and then using this information to determine the appropriate kick-down stroke, the system prepares the correct threshold in advance, ensuring consistent kick-down timing without requiring overly narrow shift line widths that would compromise hysteresis.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10100921B2Vehicle shift controller

Publication Date: 2018.10.16 HONDA MOTOR CO LTD

AI summary

A stay time integrating device integrates stay time of an accelerator pedal in each pedal stroke position within a predetermined stroke range including a click position. A click stroke calculating device calculates a click stroke based on a pedal stroke position where stay time calculated by the integrating device is the shortest. Thus, it is possible to correctly calculate the click stroke with which the accelerator pedal is actually depressed beyond the click position. In accordance with the click stroke, a control stroke calculating device updates a relationship of the control stroke with a pedal stroke. Accordingly, even if the click stroke varies from one vehicle to another, kick-down which a driver intends can be performed in synchronism with depression of the accelerator pedal beyond the click position by compensating for the variation.