Engine Combustion Chamber Partition Wall Fuel Adhesion Prevention
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Solution Overview
Problem
During engine warm-up operations, low temperatures in the combustion chambers lead to poor combustion stability of the air-fuel mixture, resulting in increased hydrocarbons and nitrogen oxides in the exhaust gas due to fuel adherence to the partition wall, which complicates the execution of a successful warm-up operation.
Innovation Solution
The engine employs a control system that coordinates the injection of fuel and air through separate injectors, creating an air layer on the partition wall to prevent fuel adhesion during the compression stroke and ensures proper ignition timing, allowing for efficient combustion by injecting a small amount of fuel after air injection, thereby reducing hydrocarbon emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel is injected into the main combustion chamber during compression stroke, then the air-fuel mixture can be prepared for combustion, but fuel adheres to the low-temperature partition wall causing poor combustion stability and increased hydrocarbon emissions
Solution Approach 1:
The combustion chamber is divided into a main combustion chamber and a sub-combustion chamber separated by a partition wall. The partition wall is further segmented with through-holes that allow controlled passage of air and fuel. This segmentation prevents fuel adhesion to the partition wall surface while enabling proper mixture preparation and combustion stability during warm-up operations.
Solution Approach 2:
Air injected into the sub-combustion chamber acts as an intermediary medium that flows through the through-holes in the partition wall. This air flow creates a protective effect that prevents direct fuel contact with the partition wall surface, thereby reducing fuel adhesion and hydrocarbon emissions while maintaining combustion stability.
2Object-generated harmful factors
If separate air and fuel injectors are used with overlapping injection periods, then an air layer can be formed on the partition wall to prevent fuel adhesion, but the device complexity increases
Solution Approach 1:
The partition wall with through-holes serves multiple functions: it separates the main and sub-combustion chambers, enables air flow from the sub-combustion chamber to the main combustion chamber, and acts as a surface for air layer formation to prevent fuel adhesion. This multi-functionality reduces the need for additional complex components while achieving fuel adhesion prevention.
Solution Approach 2:
The air injection and fuel injection systems are merged in their operational timing and spatial arrangement. Air is injected into the sub-combustion chamber and fuel is injected into the main combustion chamber with overlapping periods, creating a coordinated system where the air layer forms on the partition wall to prevent fuel adhesion without requiring separate complex control mechanisms.
3Reliability
If ignition timing is delayed during power stroke, then combustion can be optimized after fuel injection, but combustion stability deteriorates during warm-up due to low temperatures
Solution Approach 1:
Air is injected into the sub-combustion chamber during the compression stroke before ignition occurs. This preliminary air injection creates a protective air layer on the partition wall and prepares the combustion environment, preventing fuel adhesion and ensuring stable combustion conditions are established before the power stroke ignition timing is activated.
Solution Approach 2:
The injection timing and duration of air and fuel are dynamically adjusted with overlapping periods during the compression stroke. This dynamic coordination ensures that the air layer forms on the partition wall at the appropriate time, preventing fuel adhesion while maintaining optimal combustion stability and efficiency during the warm-up operation.
Data Source
AI summary
An engine is configured to ignite an air-fuel mixture with an electric spark to ignite an air-fuel mixture. The engine includes: a cylinder head including a chamber partition wall having through holes and defining a main combustion chamber and a sub-combustion chamber; a fuel injector that injects fuel into the main combustion chamber; an air injector that injects air into the sub-combustion chamber; an ignition device causes an electric discharge between an ignition electrode and the chamber partition wall; and a control system that controls the fuel and air injectors, and the ignition device. At a compression stroke during a warm-up operation, the fuel is injected throughout a first period, and the air is injected throughout a second period at least partially overlapping the first period. At a power stroke during the warm-up operation, the electric discharge is caused after the fuel is injected.