Variable Compression Ratio Engine Supercharger Response

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Solution Overview

Problem

Variable compression ratio internal combustion engines face response delay issues with superchargers during acceleration, affecting acceleration performance due to the time lag in increasing supercharging pressure.

Innovation Solution

The engine adjusts its compression ratio to a lower setting during acceleration, increasing exhaust gas pressure and reducing supercharger response time, while maintaining heat efficiency and preventing knocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the compression ratio is maintained at a high basic compression ratio to ensure heat efficiency and prevent knocking, then thermal efficiency is improved, but supercharger response time increases during acceleration

Engineering Contradiction:

Improvethermal efficiencyVSAvoidsupercharger response time

Core Design Contradiction:

Loss of energyVSLoss of time

Solution Approach 1:

The compression ratio is made dynamically adjustable rather than fixed. During acceleration, the compression ratio is temporarily reduced to increase exhaust gas pressure and improve supercharger response. The system transitions from a static high compression ratio to a dynamic variable compression ratio that adapts to operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The compression ratio parameter is changed temporarily during acceleration from the basic high compression ratio to a lower compression ratio. This parameter change increases exhaust gas pressure and energy available to the supercharger, reducing response delay while maintaining acceptable thermal efficiency.

Inventive Principle:

Principle #35Parameter changes

2Loss of time

If the compression ratio is reduced to increase exhaust gas pressure and improve supercharger response, then supercharger response time is improved, but thermal efficiency decreases

Engineering Contradiction:

Improvesupercharger response timeVSAvoidthermal efficiency

Core Design Contradiction:

Loss of timeVSLoss of energy

Solution Approach 1:

The reduced compression ratio is applied periodically or temporarily only during acceleration events rather than continuously. The system switches to lower compression ratio when acceleration is detected and returns to the basic high compression ratio when acceleration ends, minimizing the impact on overall thermal efficiency while achieving improved supercharger response when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The compression ratio is reduced in advance upon detection of acceleration demand to quickly increase exhaust gas pressure and improve supercharger response. This preliminary action prepares the system for the upcoming load increase, ensuring the supercharger can respond promptly to acceleration requests.

Inventive Principle:

Principle #10Preliminary action

3Speed

If the compression ratio is reduced during acceleration to improve supercharger response, then acceleration performance is improved, but knocking risk increases

Engineering Contradiction:

Improveacceleration performanceVSAvoidknocking risk

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors engine operating conditions including knock detection sensors. Based on feedback from knock sensors and other parameters, the control system adjusts the compression ratio appropriately during acceleration, reducing it only when and where it improves supercharger response without inducing knock, and maintaining or increasing it when knock risk is detected.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The compression ratio parameter is dynamically adjusted during acceleration based on real-time engine conditions. The system changes the compression ratio from the basic high value to a lower value selectively during acceleration events, optimizing the balance between improving supercharger response and preventing knock by adapting to actual operating conditions.

Inventive Principle:

Principle #35Parameter changes

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

This adjustment enhances acceleration performance by shortening supercharger start-up time and increasing torque, effectively addressing response delay and maintaining engine efficiency.

Implementation Method 1

a supercharger driven by the exhaust gas from the internal combustion engine for supercharging intake air to the internal combustion engine

Methodology Applied

Scientific EffectExhaust gas energy conversion: Heat Engine

Implementation Method 2

compressing air by means of a compressor attached to the rotary shaft same as the turbine shaft and supplying the compressed air into the cylinder

Methodology Applied

Scientific EffectMechanical compression: Compression

Data Source

PatentUS7627417B2Variable compression ratio internal combustion engine

Publication Date: 2009.12.01 TOYOTA JIDOSHA KK

AI summary

The invention provides a technology that enables to control response delay of the supercharger in a variable compression ratio internal combustion engine under acceleration. When the variable compression ratio internal combustion engine is under acceleration, the compression ratio of the internal combustion engine is set to a compression ratio lower than a basic compression ratio that is so determined in accordance with the running condition of the internal combustion engine to realize a predetermined heat efficiency while suppressing knocking, thereby raising the exhaust gas pressure and shortening the response time of the supercharger.