Multi-Strike Ignition for Direct-Start Engine Misfire Reduction

Solution Overview

Problem

Vehicles using direct-start control strategies for internal combustion engines experience misfires, variable torque output, and increased emissions due to the unpredictable position of the piston and improper air-fuel mixture during idle-stop operations, leading to customer dissatisfaction and increased noise, vibration, and harshness (NVH).

Innovation Solution

Implementing a multi-strike ignition operation during direct-starts, where a selected combustion chamber with a piston closer to the top dead center (TDC) is prioritized for ignition, and adjusting the spark ignition signal parameters based on piston position, engine temperature, and fuel rail pressure to enhance combustion stability and reduce emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If direct-start control strategy is used to quickly restart the engine from idle-stop conditions, then fuel consumption and emissions are reduced, but misfires and variable torque output occur due to unpredictable piston position and improper air-fuel mixing

Engineering Contradiction:

Improvefuel consumptionVSAvoidcombustion stability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The control system performs preliminary detection of piston position before initiating the direct-start sequence. By identifying that the piston is proximate to top dead center, the system can pre-adjust ignition timing and fuel injection parameters to ensure proper air-fuel mixing and combustion stability from the first combustion event after restart

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The ignition and fuel injection parameters are made dynamic rather than fixed. The control system continuously monitors piston position and adjusts ignition timing, fuel injection quantity, and injection pressure in real-time based on the detected piston position, allowing the system to adapt to the unpredictable piston location during direct-start conditions

Inventive Principle:

Principle #15Dynamics

2Loss of energy

If direct-start control strategy is used to quickly restart the engine from idle-stop conditions, then fuel consumption and emissions are reduced, but noise, vibration, and harshness (NVH) are exacerbated due to variable torque output

Engineering Contradiction:

Improvefuel consumptionVSAvoidnoise, vibration, and harshness

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The control system performs preliminary detection of piston position before initiating the direct-start sequence. By identifying that the piston is proximate to top dead center, the system can pre-adjust ignition timing and fuel injection parameters to ensure proper air-fuel mixing and combustion stability from the first combustion event after restart

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control system uses feedback from piston position detection to continuously adjust ignition and fuel injection parameters. This closed-loop control ensures that torque output remains stable during direct-start operation, reducing NVH by compensating for variations in piston position and air-fuel mixing conditions

Inventive Principle:

Principle #23Feedback

3Speed

If the piston is positioned proximate to top dead center during direct-start, then the engine can be restarted quickly, but air-fuel mixing becomes inconsistent leading to incomplete combustion

Engineering Contradiction:

Improverestart speedVSAvoidair-fuel mixing consistency

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The control system performs preliminary detection of piston position before initiating the direct-start sequence. By identifying that the piston is proximate to top dead center, the system can pre-adjust ignition timing and fuel injection parameters to ensure proper air-fuel mixing and combustion stability from the first combustion event after restart

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes key parameters including fuel injection pressure, injection duration, and ignition timing based on the detected piston position. When the piston is near top dead center, the system increases fuel injection pressure and adjusts timing to compensate for reduced mixing effectiveness, ensuring consistent combustion despite the unfavorable piston position

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 multi-strike ignition operation improves combustion efficiency, reduces emissions and torque variations, and balances current draw during engine starts, enhancing customer satisfaction by minimizing NVH and optimizing energy usage.

Implementation Method 1

ignited via a spark discharge to quickly and seamlessly re-start combustion within the engine

Methodology Applied

Scientific EffectElectrical discharge: Electric Spark

Implementation Method 2

fuel may be injected into to a selected combustion chamber

Methodology Applied

Scientific EffectFuel injection: Injector

Implementation Method 3

re-start combustion within the engine

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS8047188B2Direct-start engine operation utlizing multi-strike ignition

Publication Date: 2011.11.01 FORD GLOBAL TECH LLC

AI summary

A method for engine starting is provided. The method may include performing idle-stop operation, and during a subsequent re-start, applying multi-strike ignition operation for a first combustion cycle. In this way, improved engine starting may be achieved with reduced emissions.