Vehicle HVAC Controller Dynamic Engine Stop Duration

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Solution Overview

Problem

Conventional vehicle engine controllers that temporarily stop engines to reduce fuel consumption fail to maintain passenger compartment comfort by allowing rapid temperature changes, leading to discomfort due to fixed engine stop durations, which do not account for varying conditions such as outside temperature or passenger load.

Innovation Solution

A controller that uses sensors to detect air and evaporator temperatures, humidity, and vehicle conditions to dynamically determine engine stop duration, continuing blower fan operation and restarting the engine when necessary to maintain comfort while minimizing fuel consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the engine stop duration is set to be longer to reduce fuel consumption, then fuel economy is improved, but the temperature in the passenger compartment changes rapidly causing passenger discomfort

Engineering Contradiction:

Improvefuel consumptionVSAvoidtemperature change in passenger compartment

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The engine stop duration is made dynamic rather than fixed. The control device determines the stop duration based on real-time conditions including evaporator temperature, outside air temperature, and air conditioning load. This allows the system to adapt the stop duration to current thermal conditions, preventing passenger discomfort while maximizing fuel savings.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses feedback from temperature sensors (evaporator temperature detector, outside air temperature detector) and control devices (air conditioning control device) to continuously monitor the thermal state of the passenger compartment. This feedback loop enables the control device to adjust the engine stop duration to maintain comfort while reducing fuel consumption.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If the engine stop duration is set to be shorter to maintain passenger comfort, then temperature stability is improved, but fuel consumption increases

Engineering Contradiction:

Improvetemperature change in passenger compartmentVSAvoidfuel consumption

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The system changes the parameter of engine stop duration based on multiple input parameters including evaporator temperature, outside air temperature, and air conditioning load. By adjusting this key parameter dynamically, the system optimizes the balance between fuel consumption and passenger comfort, achieving longer stops when conditions permit and shorter stops when comfort is at risk.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a fixed engine stop duration is used to simplify control, then device complexity is reduced, but adaptability to varying conditions deteriorates

Engineering Contradiction:

Improvecontrol system complexityVSAvoidadaptability to outside temperature and passenger load

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The control device automatically determines the appropriate engine stop duration by itself, using built-in sensors and control algorithms. The system self-adjusts based on detected conditions (evaporator temperature, outside air temperature, air conditioning load) without requiring external input or complex manual configuration, achieving high adaptability with manageable complexity.

Inventive Principle:

Principle #25Self-service

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

This approach effectively reduces fuel consumption while preventing rapid temperature rises or falls in the passenger compartment, enhancing comfort by adjusting engine stop duration based on real-time conditions, thereby reducing passenger discomfort and maintaining a stable environment.

Implementation Method 1

an evaporator which is connected to the refrigerant circulation passage and which is provided in a circulation passage of air blown into the passenger compartment by the blower fan, and which air-conditions the passenger compartment

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a heat exchanger which is in communication with the coolant circulation passage and which is provided in a circulation passage of air sent into the passenger compartment by the blower fan to heat ambient air by the heat radiation from the coolant circulating in the coolant circulation passage

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentUS8347642B2HVAC controller for vehicle

Publication Date: 2013.01.08 HONDA MOTOR CO LTD

AI summary

A controller for a vehicle includes an in-passenger-compartment temperature sensor which detects the temperature of the air supplied to an evaporator by actuating a blower fan, an outside air temperature sensor, an evaporator temperature sensor which detects the temperature of the evaporator, and an engine stop duration determiner which determines an engine stop duration on the basis of the temperature detected by the evaporator temperature sensor immediately before an engine stops and the temperatures detected by the outside air temperature sensor and the in-passenger-compartment temperature sensor. An engine control unit continues the operation of the blower fan after a stop condition holds and the engine is stopped, and then restarts the engine and actuates a compressor when the engine stop duration has elapsed.