Combustion Engine Transfer Valve Timing for Gas Flushing

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Solution Overview

Problem

Internal combustion engines operating in over-expansion mode face challenges in properly flushing out combustion gases during partial load operations, leading to reduced performance and efficiency due to prolonged gas residence time and back pressure, which can limit the engine's ability to accept fresh intake air.

Innovation Solution

The engine employs a timed transfer valve and exhaust valve to cut off direct gas communication between combustion chambers before the end of the exhaust stroke, allowing a small overlap period for intake and exhaust, and uses a poppet valve with a flattened wall portion and auxiliary valve to reroute gases through the existing exhaust system, minimizing flow losses and optimizing gas expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the transfer channel remains open during the exhaust stroke to allow overexpansion, then fuel efficiency is improved through additional gas expansion, but combustion gases cannot be properly flushed out leading to reduced performance

Engineering Contradiction:

Improvefuel efficiencyVSAvoidgas flushing efficiency

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The transfer valve is timed to close before the end of the exhaust stroke, preliminarily stopping the overexpansion process before it interferes with the gas flushing function. This timing ensures that the beneficial expansion occurs first, then the system transitions to the flushing mode without conflict.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The transfer valve operates periodically, being open during the power stroke to enable overexpansion and closed during the exhaust stroke to enable gas flushing. This periodic switching allows the system to alternately achieve both fuel efficiency improvement and effective gas removal.

Inventive Principle:

Principle #19Periodic action

2Productivity

If the transfer valve closes early to enable gas flushing, then fresh intake air can be accepted properly, but the power benefits of overexpansion are lost

Engineering Contradiction:

Improveintake air acceptanceVSAvoidpower output

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The transfer valve closes preliminarily before the exhaust stroke completes, ensuring that gas flushing is enabled in time for the intake stroke. This timing allows the system to maximize the overexpansion benefit while still preparing for effective gas removal and fresh charge acceptance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The valve timing is designed to maintain continuous useful action by seamlessly transitioning from the overexpansion phase to the gas flushing phase. The close timing ensures no loss of power benefit while the exhaust valve timing ensures continuous gas removal capability.

Inventive Principle:

Principle #20Continuity of useful action

3Loss of energy

If the transfer channel is optimized for minimal longitudinal dimension, then flow losses are reduced, but the valve timing control complexity increases

Engineering Contradiction:

Improveflow lossVSAvoidvalve timing control

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The exhaust system is segmented into multiple functions: the transfer channel for overexpansion, the exhaust valve for gas removal, and the transfer valve for mode switching. This segmentation allows each component to be optimized for its specific function while the control system coordinates them through timed valve operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The transfer channel serves multiple functions: it acts as an expansion volume during the power stroke and as an exhaust passage during the exhaust stroke. This multi-functionality is achieved through the coordinated timing of the transfer valve and exhaust valve, allowing a single structural element to fulfill different roles.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enhances engine performance by ensuring efficient gas flushing, reducing engine vibrations, and maintaining power benefits during partial load operations while minimizing flow losses and heat loss, thus improving fuel efficiency and operational flexibility.

Implementation Method 1

the principle of overexpansion

Methodology Applied

Scientific EffectOverexpansion:

Implementation Method 2

a timed transfer valve and exhaust valve to cut off direct gas communication between combustion chambers

Methodology Applied

Scientific EffectGas flow control:

Implementation Method 3

uses a poppet valve with a flattened wall portion and auxiliary valve to reroute gases through the existing exhaust system, minimizing flow losses

Methodology Applied

Scientific EffectFlow loss reduction:

Data Source

PatentUS11746690B2Combustion engine

Publication Date: 2023.09.05 AIRDAPTIVE LLC

AI summary

A combustion engine is provided having combustion chambers with reciprocating pistons, intake ports and exhaust ports. Transfer ports may be provided between adjacent combustion chambers to provide a transfer channel that closes during a high load mode of operation of the engine and opens during a partial load mode of operation. Also provided are embodiments in which exhaust ports of adjacent combustion chambers are joined into a common exhaust channel that communicates with an exhaust header of the engine through valve means that open during the high load mode of operation of said engine and close during a partial load mode of operation.