Throttle Control for Centrifugal Clutch Work Vehicle Starts

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Solution Overview

Problem

Existing work vehicles with centrifugal clutches disturb the driver due to rapid engine rotational speed increases during clutch connection, leading to undesirable impacts and discomfort.

Innovation Solution

Implementing a throttle controller with a filter value deriver that adjusts throttle responsiveness based on engine rotational speed and clutch connection conditions, using a three-dimensional map to derive opening degree filter values that reduce throttle responsiveness before clutch connection, thereby smoothing the engine response.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine rotational speed increases rapidly during clutch connection, then the vehicle can start traveling quickly, but the driver experiences disturbance and discomfort due to the impact

Engineering Contradiction:

Improvevehicle start speedVSAvoiddriver disturbance

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary action by detecting the clutch connection state in advance and preemptively adjusting the throttle responsiveness before the actual clutch connection occurs. When the clutch is detected to be in the process of connecting, the throttle controller reduces throttle responsiveness, which slows down the rate of engine rotational speed increase, thereby reducing the impact and disturbance to the driver while still enabling timely vehicle start.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the clutch connection state through the clutch state detection sensor and using this information to dynamically adjust the throttle responsiveness. The throttle controller receives feedback signals about the clutch state and automatically modifies the throttle valve opening rate accordingly, creating a closed-loop control system that balances vehicle start performance with driver comfort.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If the throttle responsiveness is reduced to minimize clutch connection impact, then driver comfort improves, but the vehicle responsiveness to driver input deteriorates

Engineering Contradiction:

Improveclutch connection impactVSAvoidvehicle responsiveness

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system applies dynamics by making the throttle responsiveness adjustable rather than fixed. The throttle controller dynamically changes the throttle responsiveness based on the real-time clutch connection state detected by the sensor. When the clutch is not connecting, normal throttle responsiveness is maintained for good vehicle responsiveness. When clutch connection is detected, the system dynamically reduces throttle responsiveness to minimize impact, then restores it after connection completes, thus adapting to different operational phases.

Inventive Principle:

Principle #15Dynamics

3Reliability

If the engine rotational speed is increased quickly to prevent vehicle movement on slopes, then safety improves, but the clutch connection impact increases

Engineering Contradiction:

Improvevehicle stability on slopeVSAvoidclutch connection impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system introduces an intermediary control mechanism (the throttle controller with adjustable responsiveness) between the driver's accelerator input and the engine's rotational speed response. This intermediary smoothly modulates the throttle valve opening rate based on clutch connection state, preventing sudden engine speed increases that would cause both driver discomfort and ensuring controlled power delivery for vehicle stability on slopes without excessive impact.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Reduces driver discomfort by minimizing the impact of clutch connection through controlled throttle responsiveness, ensuring smooth vehicle start and preventing unintended movement on slopes.

Implementation Method 1

a centrifugal clutch between the engine and the transmission device

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS20250382924A1Work Vehicle

Publication Date: 2025.12.18 KUBOTA CORP

AI summary

A work vehicle includes an engine; a transmission device configured to adjust motive power from the engine; a centrifugal clutch between the engine and the transmission device; and a throttle controller configured to electronically control an opening degree of a throttle valve of the engine, the throttle controller including a filter value deriver configured to derive an opening degree filter value from an engine rotational speed of the engine and the opening degree, the throttle controller being configured to electronically control the opening degree with use of the opening degree filter value, the filter value deriver being configured to derive a first opening degree filter value for decreasing throttle responsiveness of the engine under a derivation condition of the engine rotational speed being not higher than a centrifugal clutch connection rotational speed of the centrifugal clutch.