Engine Start Reproducibility via Crankshaft Position Control

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Solution Overview

Problem

The start-stop operation of internal combustion engines in vehicles results in varying speed developments due to different cylinder charges during start optimization, leading to unpredictable and uncomfortable engine behavior, as chemical energy is not reproducibly converted into kinetic energy, causing a tendency to roll in the vehicle.

Innovation Solution

A method to increase reproducibility by calculating a maximum speed gradient for initial combustion based on the stop position, adjusting the ignition angle and inlet valve timing to achieve a set speed gradient that corresponds to the most frequent stop position, ensuring consistent engine behavior and comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If start optimization is used to enable engine restart before crankshaft synchronization, then fuel consumption is reduced and start-up time is shortened, but the speed development becomes unpredictable and varies with stop position

Engineering Contradiction:

Improvestart-up timeVSAvoidreproducibility of start behavior

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The control unit determines the stop position of the crankshaft before ignition occurs and calculates the maximum speed gradient based on this predetermined position. This preliminary determination allows the system to optimize ignition timing and fuel injection specifically tailored to each stop position, ensuring reproducible start behavior while maintaining the benefit of early restart capability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts ignition timing and fuel injection parameters based on the calculated maximum speed gradient corresponding to the specific stop position. By changing these parameters adaptively rather than using fixed values, the system achieves consistent speed development and reproducible start behavior across different stop positions

Inventive Principle:

Principle #35Parameter changes

2Productivity

If direct injection is used to enable fuel injection after inlet valve closing, then cylinder charge can be optimized for start optimization, but the cylinder charge varies with stop position causing varying speed development

Engineering Contradiction:

Improvestart optimization capabilityVSAvoidcylinder charge consistency

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The control unit determines the stop position before ignition and calculates the maximum speed gradient in advance. This preliminary calculation allows the system to predict the cylinder charge characteristics for each stop position and adjust injection parameters accordingly, ensuring consistent combustion behavior despite varying stop positions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the calculated maximum speed gradient as a feedback parameter to adjust fuel injection quantity and ignition timing. By continuously adapting the injection strategy based on the predicted cylinder charge conditions for each stop position, the system maintains stable and reproducible combustion characteristics

Inventive Principle:

Principle #23Feedback

3Reliability

If conventional start strategy is used without start optimization, then crankshaft synchronization must occur before restart, but fuel consumption increases and start-up time is longer

Engineering Contradiction:

Improvestart behavior predictabilityVSAvoidstart-up time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The control unit determines the stop position and calculates the maximum speed gradient before ignition occurs, enabling the system to prepare optimized ignition timing and fuel injection parameters in advance. This preliminary preparation allows the engine to start before crankshaft synchronization while maintaining predictable and reproducible start behavior

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts ignition timing and fuel injection parameters based on the calculated maximum speed gradient for each stop position. By changing these parameters adaptively, the system achieves both early restart capability and consistent, predictable start behavior across different operating conditions

Inventive Principle:

Principle #35Parameter changes

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

The method ensures a reproducible and comfortable start experience by reducing the maximum speed gradient to a set level, adapting the efficiency of initial combustion to match the most frequent stop position, thereby minimizing variations in engine behavior across different stop positions.

Implementation Method 1

the position of the engine after the internal combustion engine has stopped, so that, when a first tooth flank of the crankshaft sensor is detected

Methodology Applied

Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

chemical energy is not reproducibly converted into kinetic energy

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS7134412B2Method for increasing the reproducibility of the start-up during start-stop operation of an internal combustion engine

Publication Date: 2006.11.14 VITESCO TECHNOLOGIES GMBH

AI summary

This invention relates to a method for increasing the reproducibility of the start-up in the start-stop operation of an internal combustion engine of a motor vehicle with start optimization. The reproducibility of the start-up is increased by reducing a maximum speed gradient that can be achieved for different stop positions of the internal combustion engine to a set speed gradient.