Engine Torque Shock Suppression via Dynamic Cylinder Fuel Injection

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Solution Overview

Problem

Existing engine control methods fail to reliably suppress torque shock during engine stopping and restarting, particularly when engine revolution speed or transmission reduction ratio deviates from reference settings, as they do not account for varying combustion intervals and torsional vibrations in the drivetrain.

Innovation Solution

Implement a control method that determines a predetermined number of cylinders to undergo combustion after fuel supply stop, temporarily restarting fuel supply to specific cylinders based on engine revolution speed and reduction ratio, adjusting the number of injection stop and execute cylinders to align with engine torque fluctuations and reduce torque shock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a preset fuel injection pattern is invariably applied to suppress torque shock, then the control is simple and easy to implement, but the torque shock cannot be reliably suppressed when engine revolution speed or transmission reduction ratio differs from reference settings

Engineering Contradiction:
Improveease of control implementationVSAvoidreliability of torque shock suppression
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by making the fuel injection control pattern variable rather than fixed. The control device dynamically adjusts the injection pattern based on detected engine revolution speed and transmission reduction ratio, changing the number of cylinders receiving fuel injection and the timing accordingly. This dynamic adaptation ensures reliable torque shock suppression across different operating conditions while maintaining manageable control complexity through automated detection and adjustment.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If fuel supply is stopped to reduce fuel consumption, then fuel efficiency improves, but torque shock occurs during stopping and restarting

Engineering Contradiction:
Improvefuel consumptionVSAvoidtorque shock
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent applies partial action by selectively controlling fuel injection to only certain cylinders rather than all cylinders or continuous injection. During torque shock suppression periods, fuel is injected into a specific number of cylinders (less than all cylinders) to generate just enough engine torque to counteract the torque shock, rather than applying full power. This partial fuel injection achieves the necessary vibration suppression while minimizing fuel consumption compared to full-cylinder injection.

Inventive Principle:
Principle #16Partial or excessive action

3Object-affected harmful factors

If the number of cylinders receiving fuel injection is increased to suppress torque shock, then vibration control improves, but fuel consumption increases

Engineering Contradiction:
Improvevehicle vibrationVSAvoidfuel consumption
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The control device dynamically adjusts the number of cylinders receiving fuel injection based on the detected engine revolution speed and transmission reduction ratio. At different operating conditions, different numbers of cylinders are selected to receive fuel during the torque shock suppression period. This dynamic optimization ensures that the minimum necessary number of cylinders are activated to suppress vibration, avoiding unnecessary fuel consumption while maintaining effective vibration control.

Inventive Principle:
Principle #15Dynamics

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

Effectively suppresses torque shock by generating engine torque at appropriate times and durations, aligning with drivetrain torque fluctuations, thereby improving vibration control during both stopping and restarting fuel supply.

Implementation Method 1

determined whether a first predetermined number of cylinders have undergone a combustion stroke after the stop of the fuel supply

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3514353B1Control method and control device for engine
Publication Date: 2021.03.03 NISSAN MOTOR CO LTD
  • EP3514353B1 patent drawingFigure 1
  • EP3514353B1 patent drawingFigure 2~3
  • EP3514353B1 patent drawingFigure 4

AI summary

It is determined whether a predetermined fuel supply stop condition has been fulfilled; stop time vibration suppression control of, after stop of fuel supply in response to fulfillment of the predetermined fuel supply stop condition, temporarily performing fuel supply to the engine to suppress vehicle vibration is executed; and fuel supply to all cylinders is stopped after the execution of the stop time vibration suppression control. In the stop time vibration suppression control, it is determined whether a first predetermined number of cylinders according to an engine revolution speed or a reduction ratio from the engine to drive wheels have undergone a combustion stroke after the stop of the fuel supply, and in a case where the first predetermined number of cylinders have undergone the combustion stroke, fuel supply to a second predetermined number of cylinders is performed. The first predetermined number is increased as the engine revolution speed is higher, and increased as the reduction ratio from the engine to the drive wheels is higher.