Engine Torque Control Fast Exit Mode Cylinder Deactivation

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Solution Overview

Problem

Engine control systems face challenges in managing unexpected increases in engine torque output, leading to driver experience "push" or unexpected engine speed, particularly when vehicle torque requests exceed driver requests due to events like wheel drag, faults, or mode changes.

Innovation Solution

An engine control system with an immediate torque control module and a fast exit mode module that selectively adjusts torque output and deactivates engine cylinders when the estimated maximum torque output exceeds the driver torque request, mitigating the "push" by disabling spark or fuel to specific cylinders based on driver torque requests and predetermined conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine produces torque in excess of driver torque request to handle vehicle systems requests (e.g., wheel drag elimination, traction control), then vehicle stability and traction are improved, but unexpected engine speed increases occur causing driver discomfort

Engineering Contradiction:

Improvevehicle stabilityVSAvoiddriver comfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The control system continuously monitors the difference between actual engine torque output and driver torque request, and dynamically adjusts cylinder deactivation timing based on this feedback to maintain vehicle stability while preventing excessive engine speed increases that would cause driver discomfort

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically switches between different operational states (normal operation, fast exit mode with cylinder deactivation) based on real-time conditions, allowing the engine to adapt its torque output characteristics to balance vehicle stability requirements with driver comfort

Inventive Principle:

Principle #15Dynamics

2Speed

If the engine rapidly reduces torque output when vehicle torque request is aborted, then response time is improved, but driver experience unexpected engine speed changes

Engineering Contradiction:

Improvetorque response speedVSAvoiddriver comfort

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The system preemptively deactivates cylinders before the torque reduction is complete, preparing the engine for faster torque output reduction while managing the rate of change to avoid sudden engine speed drops that would be perceptible to the driver

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fast exit mode bypasses normal gradual torque reduction procedures by directly deactivating cylinders, allowing the system to rapidly reduce torque output when needed while still controlling the overall response characteristics to maintain driver comfort

Inventive Principle:

Principle #21Skipping (Rushing through)

Data Source

PatentUS8047961B2Fast exit mode engine torque control systems and methods

Publication Date: 2011.11.01 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An engine control system of a vehicle comprises a first module and a cylinder deactivation module. The first module selectively adjusts torque output by an engine based on a vehicle torque request that is greater than a driver torque request. The cylinder deactivation module selectively deactivates a cylinder of the engine when a difference between an estimated maximum torque output of the engine and the driver torque request is greater than a predetermined maximum torque.