Work Vehicle AC Compressor Control to Prevent Engine Stalls

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Solution Overview

Problem

Gasoline engines in work vehicles are prone to engine stalls when the air conditioner device is activated, especially during cold starts or when external power devices are used, due to low robustness against abrupt load changes.

Innovation Solution

Implementing an air conditioner control system that issues a compressor drive command based on engine state information, such as rotation speed, to ensure the engine is in a suitable state before driving the compressor, thereby preventing engine stalls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the air conditioner device is activated during cold start or when external power devices are used, then the air conditioning function is provided, but the engine may stall due to low robustness against abrupt load changes

Engineering Contradiction:

Improveair conditioning functionVSAvoidengine stall prevention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The control unit checks engine state information (rotation speed, load) before issuing a compressor drive command. This preliminary verification ensures the engine can handle the additional load from the compressor without stalling, allowing safe activation of air conditioning during cold start or when external power devices are in use.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors engine state information and uses this feedback to control compressor operation. The control unit adjusts compressor drive commands based on real-time engine conditions, preventing stalls while maintaining air conditioning functionality when engine capacity allows.

Inventive Principle:

Principle #23Feedback

2Speed

If the compressor is driven immediately when the air conditioner device is turned on, then the air conditioning response is fast, but the engine may stall due to abrupt load increase

Engineering Contradiction:

Improveair conditioning response speedVSAvoidengine stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

Instead of immediately driving the compressor when the air conditioner is turned on, the control unit first checks engine state information to verify the engine can handle the load. This preliminary check maintains fast response when conditions permit while preventing stalls when engine capacity is insufficient.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts compressor drive commands based on real-time engine state. The control unit modifies compressor operation according to engine rotation speed and load conditions, optimizing the balance between air conditioning response speed and engine stability.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20250319747A1Work Vehicle

Publication Date: 2025.10.16 KUBOTA CORP

AI summary

A work vehicle includes a gasoline engine, a drive cabin covering a cabin space, an air conditioner device including a compressor driven by the gasoline engine, an air conditioning unit configured to generate an air conditioning airflow supplied to the cabin space, and an air conditioner control unit configured to control the air conditioner device. The compressor is driven in response to a compressor drive command at start of the air conditioner device which compressor drive command is issued based on engine state information on a state of the gasoline engine.