Engine Stopping Position Control via Expansion Combustion

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Solution Overview

Problem

Internal combustion engines often stop at undesirable crankshaft angles, making it difficult to crank the engine and increasing the required torque capacity of the starter motor, which can lead to higher system costs and reduced reliability.

Innovation Solution

Injecting fuel into a cylinder on an expansion stroke in response to an engine stop request, when the engine speed is within specific thresholds, to control the engine's stopping position and facilitate easier restarting through expansion combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the engine stops at random crankshaft angles, then the engine can be stopped without control intervention, but the starter motor requires higher torque capacity and system cost increases

Engineering Contradiction:

Improveengine stoppingVSAvoidstarter motor torque capacity

Core Design Contradiction:

Ease of operationVSWeight of stationary object

Solution Approach 1:

The system performs preliminary action by injecting fuel into the cylinder on the expansion stroke before the engine stops, creating expansion combustion that rotates the crankshaft to a favorable stopping position. This advance action ensures the engine stops at an optimal angle, reducing the torque capacity requirements for the starter motor during subsequent engine starts.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the engine stops at unfavorable crankshaft angles, then no additional fuel injection is needed, but engine starting reliability decreases and cranking time increases

Engineering Contradiction:

Improveengine starting reliabilityVSAvoidengine cranking time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

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 allows the engine to be reliably started with a smaller starter motor and reduces engine cranking time by positioning the crankshaft at a more favorable angle, enhancing starting consistency and reducing system costs.

Implementation Method 1

injecting fuel into a cylinder on an expansion stroke in response to an engine stop request

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

combust the fuel during the expansion stroke

Methodology Applied

Scientific EffectExpansion combustion: Combustion

Data Source

PatentUS11572844B2Methods and system for stopping an internal combustion engine

Publication Date: 2023.02.07 FORD GLOBAL TECH LLC

AI summary

A method for stopping an engine within a desired crankshaft angular range is disclosed. In one example, the method may take no control actions if it is determined that the engine will stop within the desired crankshaft angular range. However, if it is determined that the engine may stop outside of the desired crankshaft angular range, expansion combustion may be initiated in a cylinder so that the engine stops in a desired crankshaft angular range.