Engine Drag Torque Control During Cylinder Deactivation Transition

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Solution Overview

Problem

Internal combustion engines experience engine drag torque during deceleration, which can lead to increased energy expenditure and noticeable torque vibrations, affecting fuel efficiency and passenger comfort.

Innovation Solution

A method that involves transitioning from a cylinder deactivation state to an all-cylinder state and immediately decreasing engine drag torque, utilizing control systems to manage airflow and throttle positions to minimize torque disturbances and energy loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the engine operates in cylinder deactivation state during deceleration, then fuel efficiency is improved, but torque vibrations become more noticeable

Engineering Contradiction:

Improvefuel efficiencyVSAvoidtorque vibrations

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The control system increases engine drag torque immediately before transitioning from cylinder deactivation to all-cylinder state. This preliminary action prepares the engine to absorb the torque disturbance that occurs during the transition, thereby reducing noticeable vibrations in the passenger compartment while maintaining fuel efficiency benefits of cylinder deactivation during deceleration

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If engine drag torque is minimized during deceleration, then energy expenditure is reduced, but torque vibrations are amplified

Engineering Contradiction:

Improveenergy expenditureVSAvoidtorque vibrations

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts engine drag torque based on the operational state. During cylinder deactivation, drag torque is minimized to reduce energy expenditure. However, when transitioning to all-cylinder state, drag torque is temporarily increased to dampen vibrations. This dynamic adjustment allows the system to optimize both energy efficiency and vibration reduction at different moments during deceleration

Inventive Principle:

Principle #15Dynamics

3Power

If the engine transitions from cylinder deactivation state to all-cylinder state, then torque capacity is increased, but torque disturbances are generated

Engineering Contradiction:

Improvetorque capacityVSAvoidtorque disturbances

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The control system applies preliminary anti-action by increasing engine drag torque right before the cylinder deactivation to all-cylinder transition. This increased drag torque acts as a counter-force to the sudden torque increase that occurs during the transition, thereby reducing the magnitude of torque disturbances transmitted to the vehicle chassis and passenger compartment while still achieving the necessary torque capacity increase

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS9416736B2Method and apparatus for controlling an internal combustion engine during a combustion transition

Publication Date: 2016.08.16 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A method for operating an internal combustion engine includes increasing engine drag torque, transitioning from a cylinder deactivation state to an all-cylinder state, and decreasing engine drag torque immediately subsequent to transitioning to the all-cylinder state.