Asynchronous and Synchronous Water Injection Valves for Intake Port Cooling

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Solution Overview

Problem

In internal combustion engines with water injection, water collection on intake port and cylinder walls reduces evaporative cooling efficiency and can mix with engine oil, causing clouding and increased crankcase pressure.

Innovation Solution

The engine employs an asynchronous injection valve and a synchronous injection valve with different injection characteristics, including angle and rate, to minimize water collection on walls by injecting water at varying angles and rates based on intake valve states, ensuring efficient vaporization and reduced mixing with engine oil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water injection is performed into the intake port, then evaporative cooling effect is improved, but water collects on wall surfaces reducing cooling efficiency and mixing with engine oil

Engineering Contradiction:
Improveintake air temperatureVSAvoidwater collection on wall surfaces
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The asynchronous injection valve performs water injection before the intake valves close, allowing water to be injected when the intake port is sealed. This preliminary action ensures water is injected at an optimal timing before airflow changes, reducing water collection on wall surfaces while maintaining evaporative cooling effectiveness

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically switches between asynchronous and synchronous injection modes based on operating conditions. The asynchronous mode (injection before intake valve closure) and synchronous mode (injection after closure) provide flexible adaptation to different engine states, optimizing water distribution and preventing wall surface accumulation

Inventive Principle:
Principle #15Dynamics

2Temperature

If large quantity of water collects on intake port or cylinder wall surface, then water mixes with engine oil causing clouding and crankcase pressure increase, but reducing water injection quantity reduces cooling effect

Engineering Contradiction:
Improveintake air coolingVSAvoidengine oil clouding and crankcase pressure
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

By injecting water asynchronously before the intake valves close, the system performs the cooling function before water can accumulate on wall surfaces. This preliminary injection action ensures water evaporates in the intake air flow rather than collecting and mixing with engine oil, preventing both cooling loss and oil contamination

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system converts the potential harm of water injection (wall surface accumulation) into a benefit by timing the injection to occur when the intake port is sealed. This transforms what would be harmful wall wetting into effective evaporative cooling of intake air, while preventing oil mixing and crankcase pressure issues

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

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 limits port and liner wall wetting, preventing engine oil clouding and crankcase pressure increases, while maintaining effective water injection and airflow management.

Implementation Method 1

injected water is vaporized to cool intake air

Methodology Applied
Scientific EffectEvaporative cooling: Evaporation

Implementation Method 2

an asynchronous injection valve configured to inject water into the intake port when the one or more intake valves are closed, and a synchronous injection valve configured to inject water into the intake port when the one or more intake valves are open

Methodology Applied
Scientific EffectFluid injection: Jet

Data Source

PatentEP4257819B1Internal combustion engine
Publication Date: 2025.03.26 TOYOTA JIDOSHA KK
  • EP4257819B1 patent drawingFigure 1~2
  • EP4257819B1 patent drawingFigure 3~4

AI summary

An internal combustion engine includes an asynchronous injection valve configured to inject water into an intake port when one or more intake valves are closed and a synchronous injection valve configured to inject water into the intake port when the one or more intake valves are open. The asynchronous injection valve and the synchronous injection valve are configured to have injection characteristics that are different between the asynchronous injection valve and the synchronous injection valve.