2-Cycle Engine Intake Exhaust Timing Inversion

Solution Overview

Problem

2-stroke internal combustion engines suffer from inefficiencies such as unburned air/fuel mixture escape, pollution, and limited torque due to their design, which results in lower power output and higher emissions compared to 4-stroke engines.

Innovation Solution

The engine design is modified to reverse the sequence of the intake and exhaust cycles, with the intake cycle starting earlier and lasting longer than the exhaust cycle, and incorporating a trapezoidal shaped exhaust port for improved scavenging, allowing for a longer power stroke and unidirectional airflow, eliminating the need for a turbocharged air pump.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a traditional 2-cycle engine design is used, then the engine has a simpler structure and higher power-to-weight ratio, but unburned air/fuel mixture escapes into the exhaust and exhaust gas remains in the cylinder during the following cycle, reducing efficiency and increasing pollution

Engineering Contradiction:

Improveengine structureVSAvoidfuel efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent inverts the traditional sequence by having the exhaust valve open before the intake port, rather than after. This reversal allows the exhaust to clear from the cylinder before fresh charge enters, preventing the mixing of exhaust gases with the fresh air/fuel mixture and eliminating the energy loss associated with re-compressing and re-burning exhaust gases.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful effect of exhaust back-pressure into a beneficial timing mechanism. By opening the exhaust valve early in the downward stroke, the back-pressure helps seal the intake port longer, preventing premature entry of fresh charge and ensuring complete exhaust clearance before intake begins, thus improving fuel efficiency without adding complexity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Device complexity

If a traditional 2-cycle engine design is used, then the engine has a simpler structure, but a significant portion of unburned air/fuel mixture escapes into the exhaust, increasing pollution

Engineering Contradiction:

Improveengine structureVSAvoidpollution

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the traditional sequence by having the exhaust valve open before the intake port, rather than after. This reversal allows the exhaust to clear from the cylinder before fresh charge enters, preventing the mixing of exhaust gases with the fresh air/fuel mixture and eliminating the energy loss associated with re-compressing and re-burning exhaust gases.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful effect of exhaust back-pressure into a beneficial timing mechanism. By opening the exhaust valve early in the downward stroke, the back-pressure helps seal the intake port longer, preventing premature entry of fresh charge and ensuring complete exhaust clearance before intake begins, thus improving fuel efficiency without adding complexity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If a traditional 2-cycle engine design is used, then the engine operates with ports for intake, but the exhaust cycle and intake cycle overlap, limiting torque production

Engineering Contradiction:

Improveoperation simplicityVSAvoidtorque

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent inverts the traditional sequence by having the exhaust valve open before the intake port, rather than after. This reversal allows the exhaust to clear from the cylinder before fresh charge enters, preventing the mixing of exhaust gases with the fresh air/fuel mixture and eliminating the energy loss associated with re-compressing and re-burning exhaust gases.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs dynamic timing control where the exhaust valve remains open longer into the downward stroke than in traditional designs, and the intake port timing is adjusted to open later. This dynamic sequencing optimizes the overlap period to maximize torque production while ensuring complete exhaust clearance, allowing the engine to maintain operational simplicity while improving force characteristics.

Inventive Principle:

Principle #15Dynamics

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 configuration enhances fuel efficiency, reduces pollution, increases torque, and ensures complete combustion by maintaining fresh air flow, resulting in a more environmentally friendly and powerful 2-stroke engine.

Implementation Method 1

a piston located within a bore in the cylinder head for linear movement therein, and a crankshaft located within the engine block and operatively connected to the piston

Methodology Applied

Scientific EffectMechanical energy conversion:

Implementation Method 2

The air/fuel mixture, once ignited, expands rapidly and forces the piston downward. This is referred to as the 'power' stroke

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 3

The exhaust port preferably has a trapezoidal shape in cross section for better timed and complete cylinder scavenging

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11293358B12-cycle engine

Publication Date: 2022.04.05 PARKER BILLY RAY

AI summary

A 2-cycle internal combustion engine in which the intake cycle begins before and ends after the exhaust cycle, resulting in a longer power stroke, increased torque and greater efficiency is disclosed herein. In the preferred embodiment, the 2-cycle engine has a power stroke of about 160 degrees, an exhaust stage of about 70 degrees, and an intake cycle of about 110-115 degrees.