Vehicle Engine Control for Cabin Temperature Threshold Timing

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Solution Overview

Problem

The frequent stopping and starting of a vehicle's engine in hybrid electric vehicles, driven by the need to maintain cabin temperature, affects fuel economy, driveability, and noise levels due to sensitive temperature thresholds.

Innovation Solution

A control system that determines the time until a comfort threshold is reached based on vehicle environment and interior conditions, and only requests the engine to run if this time is less than a predetermined minimum, thereby minimizing unnecessary engine cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the engine is stopped when cabin temperature is below threshold, then fuel economy is improved, but frequent stopping and starting occurs which worsens driveability and increases noise vibration and harshness

Engineering Contradiction:

Improvefuel economyVSAvoiddriveability

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The system performs preliminary action by determining the time until the cabin temperature reaches the threshold before actually stopping the engine. By calculating whether this time is greater than a minimum time threshold, the system prevents premature engine shutdown that would cause frequent cycling. This preliminary calculation allows the system to maintain the engine running when stopping would be detrimental, thus improving driveability while still pursuing fuel economy benefits.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If the engine is stopped to save fuel, then fuel economy is improved, but noise vibration and harshness increases due to frequent starts and stops

Engineering Contradiction:

Improvefuel economyVSAvoidnoise vibration and harshness

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system calculates the time until threshold temperature is reached before making the stop decision. This preliminary action identifies conditions where stopping would lead to frequent cycling, allowing the system to avoid those stops and reduce noise vibration and harshness while still achieving fuel economy improvements in appropriate conditions.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If the engine is stopped when cabin temperature is slightly below threshold, then fuel economy is improved, but the cabin temperature would quickly exceed threshold causing frequent engine starts

Engineering Contradiction:

Improvefuel economyVSAvoidtemperature control stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system performs a preliminary calculation of the time required for cabin temperature to reach the threshold before stopping the engine. By comparing this calculated time against a minimum time threshold, the system ensures that stops are only made when the temperature is likely to remain below threshold for a sufficient duration. This prevents stops when temperature is only slightly below threshold and would quickly rise again, thereby maintaining temperature control stability while still achieving fuel economy benefits.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8151581B2System and method for controlling a vehicle engine

Publication Date: 2012.04.10 FORD GLOBAL TECH LLC

AI summary

Systems and methods to control an engine configured to drive a compressor of a vehicle air conditioning system having a desired temperature are provided. A time until a threshold is reached is determined based on an environment condition and a vehicle interior condition. A request for the engine to run is removed if the time is greater than a minimum time.