Adaptive Engine Torque Control for Vehicle Attitude Stability

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Solution Overview

Problem

In multi-cylinder internal combustion engines, the transition between all-cylinder and reduced-cylinder operation modes leads to differences in torque reduction timing, causing vehicle behavior inconsistencies and a less responsive steering experience due to varying combustion intervals and engine operating conditions, particularly at low engine speeds.

Innovation Solution

A control device that adjusts the rate of change in engine torque based on the number of combustion events per unit time, increasing the rate of torque reduction as the number of deactivated cylinders or engine speed decreases, to synchronize torque reduction with steering wheel operations and improve responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the engine operates in reduced-cylinder mode to improve fuel economy, then fuel consumption is reduced, but the combustion interval increases causing delayed torque reduction response

Engineering Contradiction:

Improvefuel consumptionVSAvoidtorque reduction response speed

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent applies dynamics by making the torque reduction rate adaptive rather than fixed. The control device dynamically adjusts the torque reduction rate based on real-time detection of cylinder operation mode (all-cylinder or reduced-cylinder mode) and engine speed, ensuring optimal response characteristics under varying operating conditions while maintaining fuel economy benefits of reduced-cylinder mode

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of torque reduction rate based on cylinder operation mode and engine speed. By detecting whether the engine is in all-cylinder or reduced-cylinder mode and the current engine speed, the control device adjusts the torque reduction rate parameter to compensate for the increased combustion interval in reduced-cylinder mode, thereby maintaining consistent torque reduction timing across different operation modes

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If the combustion interval is increased in reduced-cylinder operation, then fuel economy is improved, but the timing consistency between operation modes deteriorates

Engineering Contradiction:

Improvefuel economyVSAvoidtiming consistency

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent implements feedback by continuously detecting the cylinder operation mode and engine speed, then using this information to adjust the torque reduction rate. This closed-loop control ensures that the torque reduction timing remains consistent between all-cylinder and reduced-cylinder modes by compensating for the different combustion intervals through adaptive parameter adjustment

Inventive Principle:

Principle #23Feedback

3Use of energy by moving object

If the engine speed is reduced to improve fuel efficiency, then fuel consumption decreases, but the torque reduction responsiveness deteriorates

Engineering Contradiction:

Improvefuel consumptionVSAvoidtorque reduction timing delay

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent changes the torque reduction rate parameter based on engine speed detection. When engine speed is low, the control device adjusts the torque reduction rate to compensate for the naturally longer combustion interval, ensuring that torque reduction responsiveness is maintained across different engine speed ranges while preserving fuel efficiency benefits

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3415746B1Vehicle control device

Publication Date: 2020.06.17 MAZDA MOTOR CORP

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AI summary

A control device for a vehicle includes: an engine (10); an engine torque adjustment mechanism for adjusting an output torque of the engine; and a PCM (50) configured, upon satisfaction of a vehicle attitude control executing condition that the vehicle is traveling and a steering angle-related value is increasing, to control the engine torque adjustment mechanism to reduce the engine torque to thereby generate deceleration of the vehicle so as to control vehicle attitude. The PCM (50) is further configured to set a rate of change in the engine output torque being reduced, such that the rate of change becomes larger as the number of times of combustion per unit time in the engine (10) becomes smaller, and to control the engine torque adjustment mechanism to reduce the engine output torque according to the rate of change set by the torque reduction change rate-setting part.