Internal Combustion Engine Valve Recess Asymmetry

Solution Overview

Problem

Conventional internal combustion engines experience increased emissions due to the inclination of the central axis of swirl flow caused by uneven forward and backward tumble flows, leading to inefficient fuel combustion and potential smoke generation.

Innovation Solution

The engine design incorporates specific valve recess configurations on the piston, with the intake-side valve recess inclined toward the center and the exhaust-side valve recess inclined outward, and the use of both tangential and helical intake ports, where the tangential port generates a larger tumble flow, to balance and reduce the effects of tumble flows on swirl flow, thereby minimizing emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a tangential port is used to generate swirl flow, then fuel vaporization and atomization are accelerated, but the central axis of swirl flow becomes inclined causing increased emission

Engineering Contradiction:

Improvefuel combustion efficiencyVSAvoidemission

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetry by configuring the valve recesses with different inclination directions: the first valve recess inclines toward the center of the combustion chamber while the second valve recess inclines toward the periphery. This asymmetric configuration creates opposing tumble flows that cancel each other's inclining effects on the swirl flow central axis, maintaining combustion efficiency while reducing emission.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent uses the counterweight principle by introducing two valve recesses with opposite inclination directions that generate counterbalancing tumble flows. The first valve recess generates a tumble flow in one direction while the second valve recess generates a tumble flow in the opposite direction, creating a balancing effect that prevents the swirl flow central axis from inclining and reduces emission.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

2Productivity

If tumble flow is generated to improve fuel mixing, then combustion efficiency increases, but swirl flow central axis inclination occurs reducing air-fuel mixture ratio

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidair-fuel mixture ratio

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies asymmetry by configuring the valve recesses with different inclination directions: the first valve recess inclines toward the center of the combustion chamber while the second valve recess inclines toward the periphery. This asymmetric configuration creates opposing tumble flows that cancel each other's inclining effects on the swirl flow central axis, maintaining combustion efficiency while reducing emission.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent uses the counterweight principle by introducing two valve recesses with opposite inclination directions that generate counterbalancing tumble flows. The first valve recess generates a tumble flow in one direction while the second valve recess generates a tumble flow in the opposite direction, creating a balancing effect that prevents the swirl flow central axis from inclining and reduces emission.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 balances forward and backward tumble flows, reducing their combined impact on swirl flow, leading to improved fuel distribution and combustion efficiency, thereby decreasing emissions and enhancing engine performance.

Implementation Method 1

a forward tumble flow which is a tumble flow flowing along an upper surface in the combustion chamber from the intake port toward an exhaust port

Methodology Applied

Scientific EffectTumble flow:

Implementation Method 2

a backward tumble flow which is a tumble flow flowing along a lower surface in the combustion chamber from the intake port toward the exhaust port

Methodology Applied

Scientific EffectTumble flow:

Implementation Method 3

a swirl flow (a vortex flow in a circumferential direction of a cylinder) generated in the combustion chamber

Methodology Applied

Scientific EffectSwirl flow:

Implementation Method 4

vaporization and atomization of fuel is accelerated by stirring in the combustion chamber

Methodology Applied

Scientific EffectVaporization: Evaporation

Implementation Method 5

vaporization and atomization of fuel is accelerated by stirring in the combustion chamber

Methodology Applied

Scientific EffectAtomization:

Data Source

PatentUS10711685B2Internal combustion engine

Publication Date: 2020.07.14 TOYOTA JIDOSHA KK

AI summary

When an amount of a backward tumble flow is smaller than an amount of a forward tumble flow, the intake-side valve recess is used as a first valve recess and the exhaust-side valve recess is used as a second valve recess. When the amount of the backward tumble flow is larger than the amount of the forward tumble flow, the exhaust-side valve recess is used as a first valve recess and the intake-side valve recess is used as a second valve recess. An inclination angle of the first valve recess is larger than an inclination angle of the second valve recess when comparing the inclination angle such that a height of the recess decreases gradually toward an inner side of a cross-section.