Cylinder-Specific Fueling Error Compensation for Engine Restart

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Solution Overview

Problem

Existing engine restart systems fail to adequately address cylinder-to-cylinder air-to-fuel ratio variations during engine cranking, leading to engine speed fluctuations and NVH issues due to insufficient learning and compensation of fueling errors tied to combustion events.

Innovation Solution

A method that correlates fueling errors with engine cylinders based on the number of combustion events and cylinder identity during engine restart, using crankshaft speed fluctuations to identify and compensate for air-to-fuel ratio errors, and stores these corrections in a look-up table for subsequent engine restarts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fueling adjustments are made based on engine speed-load conditions as in Kita, then general air-to-fuel ratio control is achieved, but cylinder-to-cylinder air-to-fuel ratio variations are not sufficiently addressed

Engineering Contradiction:

Improveair-to-fuel ratio controlVSAvoidcylinder-specific fueling error detection

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the fueling error analysis by dividing it into individual cylinder contributions. By analyzing crankshaft speed fluctuations and attributing them to specific cylinders based on firing order and crankshaft position, the system isolates cylinder-specific fueling errors from aggregate engine behavior, enabling precise identification of which cylinder is misfiring or underperforming.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements feedback by continuously monitoring crankshaft speed fluctuations during engine operation and using these measurements to identify and correct cylinder-specific fueling errors. The learned fueling corrections are applied in real-time to adjust fuel injection timing and quantity for each cylinder, creating a closed-loop control system that improves air-to-fuel ratio precision.

Inventive Principle:

Principle #23Feedback

2Power

If fueling corrections are learned as a function of engine speed-load conditions, then general torque control is improved, but fueling errors cancel out over time and cylinder-specific deviations persist

Engineering Contradiction:

Improvetorque controlVSAvoidengine startability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies preliminary action by learning and storing cylinder-specific fueling corrections during normal engine operation under various speed-load conditions. These pre-learned corrections are then retrieved and applied during engine restart events, allowing the system to anticipate and compensate for cylinder-specific fueling deviations before they cause performance issues, rather than reacting to problems after they occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes parameters by transitioning from general engine-wide fueling control to cylinder-specific fueling control. By modifying the control parameters to include individual cylinder identification and specific fueling corrections for each cylinder, the system transforms the control strategy to address cylinder-to-cylinder variations while maintaining overall engine performance.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If engine restart systems use general air-to-fuel ratio control, then fuel savings are achieved, but engine speed fluctuations and NVH issues occur during cranking

Engineering Contradiction:

Improvefuel consumptionVSAvoidengine speed fluctuations

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by implementing cylinder-specific fueling control rather than uniform engine-wide control. Each cylinder receives tailored fueling corrections based on its individual performance characteristics and identified deviations, allowing precise local adjustment of air-to-fuel ratio for each cylinder while maintaining overall fuel efficiency during engine restart and operation.

Inventive Principle:

Principle #3Local quality

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 improves engine startability by reducing engine speed and torque fluctuations, thereby minimizing NVH issues and enhancing the quality of engine restarts.

Implementation Method 1

crankshaft speed fluctuations to identify and compensate for air-to-fuel ratio errors

Methodology Applied

Scientific EffectCrankshaft speed fluctuation detection:

Data Source

PatentUS9328680B2Method and system for engine speed control

Publication Date: 2016.05.03 FORD GLOBAL TECH LLC

AI summary

Methods and systems are provided for accurately determining cylinder fueling errors during an automatic engine restart. Fueling errors may be learned during a preceding engine restart on a cylinder-specific and combustion event-specific basis. The learned fueling errors may then be applied during a subsequent engine restart on the same cylinder-specific and combustion event-specific basis to better anticipate and compensate for engine cranking air-to-fuel ratio deviations.