Vehicle Control Unit Engine Stop-Start Strategy for Air Conditioning

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Solution Overview

Problem

Existing vehicle control units face challenges in balancing vehicle speed control and air conditioning performance, leading to degradation of air conditioning performance during engine deactivation and reduced fuel efficiency when prioritizing air conditioning.

Innovation Solution

An integrated control unit that adjusts vehicle speed control, power train control, and air conditioning control based on the operation of the air conditioning system, ensuring continuous air conditioning performance while optimizing fuel efficiency by modifying the engine's operation periods and acceleration factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the engine is repeatedly driven and stopped to maintain target cruising speed, then fuel efficiency is improved, but air conditioning performance deteriorates

Engineering Contradiction:

Improvefuel efficiencyVSAvoidair conditioning performance

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control unit dynamically adjusts the engine stop/start strategy based on air conditioning system state. When the air conditioning system requires engine power (compressor operation, heater operation), the control unit prevents engine stoppage or extends operation periods, thereby adapting the fuel efficiency optimization to the current thermal management needs.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control unit continuously monitors the operation state of the air conditioning system and uses this feedback to modify the vehicle speed control strategy. When air conditioning demand is detected, the system adjusts engine operation timing to ensure continuous compressor operation or heater availability, creating a closed-loop control that balances fuel efficiency with thermal comfort requirements.

Inventive Principle:

Principle #23Feedback

2Reliability

If the engine operation is extended to maintain air conditioning performance, then air conditioning reliability is improved, but fuel efficiency deteriorates

Engineering Contradiction:

Improveair conditioning performanceVSAvoidfuel efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of continuously running the engine, the control unit applies partial action by selectively extending engine operation periods only when air conditioning demand is detected. The system uses minimal necessary engine runtime to maintain air conditioning functionality while allowing engine stoppage during periods of low thermal demand, thereby avoiding excessive fuel consumption.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The control unit changes operational parameters (engine stop/start timing, operation duration) based on air conditioning system state. When air conditioning is active, the system adjusts these parameters to ensure continuous compressor operation or heater availability, optimizing the balance between reliability and energy consumption through dynamic parameter modification.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the vehicle speed control is optimized for fuel efficiency, then energy consumption is reduced, but air conditioning system operation is compromised

Engineering Contradiction:

Improveenergy consumptionVSAvoidair conditioning system operation

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control unit integrates multiple control functions (vehicle speed control, powertrain control, air conditioning control) into a unified system. This multi-functional approach allows the system to simultaneously optimize for fuel efficiency while ensuring air conditioning reliability by coordinating engine operation, vehicle speed, and thermal management requirements through a single control decision-making process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11511728B2Control unit for controlling traveling state and air conditioning state

Publication Date: 2022.11.29 DENSO CORP

AI summary

A control unit that controls a travelling state and an air conditioning state of a vehicle includes: a drive control unit performing a vehicle speed control and a power train control, the vehicle speed control selectively executing an acceleration operation where an engine mounted on the vehicle is operated and a deceleration operation where the engine is stopped to allow the vehicle to coast, the power train control selectively executing activation or deactivation of the engine; m and an air conditioning control unit that controls an air conditioning system provided in the vehicle to execute an air conditioning control. A content of control is changed for at least one of the vehicle speed control, the power train control and the air-conditioning control while the air conditioning system is operating, compared to a case where the air conditioning system is not operating.