Engine Firing Sequence Control for Cylinder Deactivation Vibration

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Solution Overview

Problem

Existing engine cylinder deactivation systems often increase noise and vibration when adjusting the firing sequence, limiting their applicability due to lack of consideration for noise and vibration performance.

Innovation Solution

A system comprising a vibration prediction module and a firing sequence module that predicts and optimizes the engine firing sequence to balance torque output, fuel economy, and vibration by estimating torque pulses and modal responses, allowing for the selection of firing sequence options that minimize vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If cylinder deactivation is implemented to decrease fuel consumption, then fuel economy is improved, but vibration increases

Engineering Contradiction:

Improvefuel consumptionVSAvoidvibration

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the firing sequence of engine cylinders based on real-time modal response predictions. When cylinders are deactivated, the control system modifies the firing order and timing of remaining active cylinders to adapt to changing vibration characteristics, thereby minimizing vibration while maintaining fuel economy benefits

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters including spark timing, injection timing, and valve timing for deactivated and active cylinders. By adjusting these parameters, the system optimizes the firing sequence to reduce vibration caused by uneven combustion forces when cylinders are deactivated

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If firing sequence is adjusted during cylinder deactivation, then vibration can be reduced, but system complexity increases

Engineering Contradiction:

ImprovevibrationVSAvoidcontrol system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system performs preliminary calculations of modal responses for different firing sequence options before actual cylinder deactivation occurs. By pre-computing vibration predictions and selecting optimal firing sequences in advance, the system avoids complex real-time adjustments while achieving vibration reduction

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses simplified models and pre-characterized modal response data to predict vibration behavior without requiring complex real-time simulations. This copying approach using predetermined vibration characteristics reduces computational complexity while maintaining accurate vibration prediction

Inventive Principle:

Principle #26Copying

Data Source

PatentUS9726139B2System and method for controlling a firing sequence of an engine to reduce vibration when cylinders of the engine are deactivated

Publication Date: 2017.08.08 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A system according to the principles of the present disclosure includes a vibration prediction module and a firing sequence module. The vibration prediction module predicts a modal response of a vehicle based on a firing sequence of an engine when a cylinder of the engine is deactivated. The firing sequence module adjusts the firing sequence of the engine based on the predicted modal response of the vehicle.