Engine Controller Mode Switching for Industrial Vehicle Operability

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Solution Overview

Problem

The installation of exhaust gas purification devices on working vehicles is hindered by their larger and heavier size, restricting engine room space and exposing engine controllers to high exhaust heat and low-frequency oscillations, leading to poor operability and comfort due to the gap between operator expectations and vehicle responses, especially under isochronous control.

Innovation Solution

A working vehicle with an engine controller that can select between isochronous and droop control modes based on brake operation states, allowing for improved control mode switching and maintaining a fixed rotation speed during travel while adjusting to load changes during work, along with a control mode selection switch and display device for operator convenience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If exhaust gas purification device is mounted to the engine, then emission control is improved, but engine room space is restricted and engine controller installation is constrained

Engineering Contradiction:
Improveemission controlVSAvoidengine room space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The engine controller is relocated from the traditional engine compartment to the driver's cab, utilizing a different spatial dimension. This resolves the space constraint caused by the exhaust gas purification device while maintaining emission control functionality through continued connection to the engine via communication interfaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

A communication interface (CAN bus or similar) acts as an intermediary between the engine controller in the cab and the engine in the engine room. This allows the controller to be positioned away from the engine while still maintaining control functionality, thus resolving the spatial conflict.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If engine controller is installed near the engine, then control responsiveness is improved, but exposure to exhaust heat and oscillation increases

Engineering Contradiction:
Improvecontrol responsivenessVSAvoidexhaust heat and oscillation
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The engine controller is extracted from the harsh environment near the engine and relocated to the protected driver's cab. This eliminates exposure to exhaust heat and low-frequency oscillation while maintaining control functionality through remote communication interfaces.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Communication interfaces serve as intermediaries that transmit control signals and data between the engine controller in the cab and the engine, enabling responsive control without direct physical proximity to the engine's harmful environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If isochronous control is used, then vehicle speed regulation is improved, but brake response feels delayed and operability deteriorates

Engineering Contradiction:
Improvevehicle speed regulationVSAvoidbrake response
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The control system dynamically switches between isochronous control and droop control based on operating conditions. During braking operations, the system transitions to droop control which provides more natural brake response characteristics, while maintaining isochronous control for steady-state speed regulation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control parameter (control mode) is changed based on operating conditions. The system monitors brake operation status and switches control modes accordingly, changing from isochronous control to droop control during braking to improve operability while maintaining speed regulation during normal operation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3124774B1Industrial vehicle
Publication Date: 2020.05.27 YANMAR CO LTD
  • EP3124774B1 patent drawingFigure 1
  • EP3124774B1 patent drawingFigure 2
  • EP3124774B1 patent drawingFigure 3

AI summary

The present invention aims at providing a working vehicle which can make an operator feel favorable operability. An engine controller (311) selects any one of an isochronous control and a droop control and controls an engine (5), and is provided with a control mode selection switch (350) which can alternatively select the isochronous control and the droop control. In the case that the isochronous control is designated by the control mode selection switch (350), the engine (5) is controlled according to the isochronous control when one of right and left brake operation devices (251, 251) is in a non-operation state, and the engine (5) is controlled according to the droop control when both of the right and left brake operation devices (251, 251) are in an operation state.