Industrial Vehicle Speed Control via Dynamic Accelerator Limiting

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Industrial vehicles using engines as a drive source face challenges in improving fuel economy due to inefficient speed control mechanisms.

Innovation Solution

A vehicle speed control device that includes a vehicle speed detector and a controller to derive and set vehicle speed limit values, adjusting engine rotation speed to control industrial vehicle speed, particularly by varying the speed limit based on accelerator pedal operation and actual speed, thereby optimizing fuel efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the vehicle speed control device limits vehicle acceleration by setting upper limit values based on actual speed and predetermined limit values, then fuel economy is improved, but vehicle acceleration performance may be restricted

Engineering Contradiction:
Improvefuel economyVSAvoidvehicle acceleration
Core Design Contradiction:
Use of energy by moving objectVSSpeed

Solution Approach 1:

The speed limit value is not fixed but dynamically adjusted based on the deviation between target speed and actual speed. When deviation is large, the speed limit value is set higher to allow faster acceleration; when deviation is small, the speed limit value is reduced to improve fuel economy. This dynamic adjustment resolves the contradiction between acceleration performance and fuel economy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of speed limit value based on operating conditions (deviation between target and actual speed). By varying this parameter according to real-time feedback, the system achieves both good acceleration response and improved fuel economy, resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the controller derives vehicle speed limit values by adding predetermined limit values to actual vehicle speed, then fuel consumption is reduced, but the vehicle may not reach maximum speed quickly enough

Engineering Contradiction:
Improvefuel consumptionVSAvoidtime to reach maximum speed
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The speed limit value is dynamically adjusted based on the deviation between target speed and actual speed. When the deviation is large (vehicle needs to accelerate quickly), the speed limit value is set higher, reducing time loss. When the deviation is small (vehicle is near target speed), the speed limit value is reduced to minimize energy loss. This dynamic approach resolves the contradiction between fuel consumption and time to reach maximum speed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller preliminarily sets an appropriate speed limit value before the vehicle reaches the target speed, based on the current deviation. This preliminary action ensures that the vehicle can accelerate efficiently without excessive fuel consumption, resolving the contradiction between energy loss and time loss.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If the vehicle speed control device continuously adjusts engine rotation speed to maintain speed within limit values, then fuel efficiency is improved, but control system complexity increases

Engineering Contradiction:
Improvefuel efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The control system uses feedback from the vehicle speed detector to continuously monitor actual speed and compare it with the target speed. Based on this feedback, the controller adjusts the speed limit value and engine rotation speed to maintain optimal fuel efficiency. The feedback mechanism enables improved fuel efficiency without requiring overly complex control logic.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system automatically adjusts the speed limit value and engine rotation speed based on real-time speed deviation, without requiring manual intervention. This self-service capability improves fuel efficiency while keeping the control system relatively simple, as the system manages its own optimization.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3222481B1Vehicle speed control device for industrial vehicle
Publication Date: 2021.09.15 TOYOTA INDUSTRIES CORP
  • EP3222481B1 patent drawingFigure 1
  • EP3222481B1 patent drawingFigure 2~3
  • EP3222481B1 patent drawingFigure 4

AI summary

A vehicle speed control device for an industrial vehicle is configured to control a vehicle speed of the industrial vehicle. The vehicle speed control device includes an operation detector that is configured to detect whether an accelerator pedal is being operated and a controller that is configured to control the vehicle speed of the industrial vehicle by controlling the rotation speed of the engine. The controller is configured to derive a vehicle speed limit value that increases during an operated state of the accelerator pedal and decreases during a non-operated state of the accelerator pedal, and set an upper limit value of the vehicle speed to the derived vehicle speed limit value.