Internal Combustion Engine Fuel Injection Control
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Solution Overview
Problem
Existing internal combustion engines face challenges in reducing NOx emissions while maintaining the homogeneity of the air-fuel mixture, especially when injecting a small amount of ignition fuel, which can lead to decreased injection performance and deteriorated mixture homogeneity due to cooling fuel injection.
Innovation Solution
The engine employs an electronic control unit to manage fuel injection modes, allowing for single-stage or multiple-stage injection of cooling fuel from the second fuel injection valve, with the option to inject additional cooling fuel from the first fuel injection valve during intake valve opening, ensuring the homogeneity of the air-fuel mixture and reducing NOx emissions by optimizing fuel distribution and ignition timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a small amount of ignition fuel is injected from the in-cylinder fuel injection valve to reduce NOx emissions, then the amount of NOx emissions is reduced, but the injection valve is not sufficiently cooled and injection performance decreases
Solution Approach 1:
The fuel injection system is divided into two separate injection valves: a first fuel injection valve for injecting homogenization fuel into the intake passage, and a second fuel injection valve for injecting ignition fuel into the combustion chamber. This segmentation allows the second valve to receive sufficient cooling fuel without compromising the homogeneity of the air-fuel mixture formed by the first valve.
Solution Approach 2:
The first fuel injection valve acts as an intermediary that supplies homogenization fuel to the intake passage, which then mixes with air before entering the combustion chamber. This intermediary approach ensures that the cooling fuel injected by the second valve does not directly deteriorate the homogeneity of the main air-fuel mixture.
2Temperature
If cooling fuel is injected from the in-cylinder fuel injection valve to cool the valve and combustion chamber, then cooling effect is achieved, but the homogeneity of the homogeneous air-fuel mixture deteriorates
Solution Approach 1:
The fuel injection function is segmented between two valves: the first valve injects homogenization fuel into the intake passage where it mixes with air to form a homogeneous mixture, while the second valve injects cooling fuel directly into the combustion chamber. This segmentation isolates the cooling fuel injection from the homogenization process.
Solution Approach 2:
Cooling fuel is injected locally into the combustion chamber near the ignition plug rather than being mixed with the main air-fuel mixture in the intake passage. This local injection provides cooling effect where needed while preserving the overall homogeneity of the air-fuel mixture formed by the first injection valve.
3Reliability
If cooling fuel is injected to cool the in-cylinder fuel injection valve, then injection performance is maintained, but the homogeneity of the air-fuel mixture deteriorates
Solution Approach 1:
The system segments the fuel injection into two separate valves with distinct functions: the first valve handles homogenization fuel injection into the intake passage, while the second valve handles both ignition fuel injection and cooling fuel injection into the combustion chamber. This segmentation resolves the conflict between maintaining injection performance through cooling and preserving mixture homogeneity.
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 approach effectively suppresses the deterioration of air-fuel mixture homogeneity and reduces NOx emissions by strategically managing fuel injection and ignition timing, maintaining combustion efficiency and stability even under lean burn conditions.
Implementation Method 1
the in-cylinder fuel injection valve is not sufficiently cooled by the latent heat of vaporization at the time of fuel injection
Data Source
AI summary
An electronic control unit of an internal combustion engine is configured to, when cooling fuel is supplied to a combustion chamber, calculate a target amount of supply of the cooling fuel and calculate a first upper limit injection amount that is an upper limit of an amount of fuel allowed to be injected from a second valve as the cooling fuel, when the target amount of supply is less than or equal to the first upper limit injection amount, supply the cooling fuel in the entire target amount of supply from the second valve to the combustion chamber in a first mode in which single-stage injection is performed, and, when the target amount of supply is greater than the first upper limit injection amount, supply the cooling fuel to the combustion chamber in a second mode in which the cooling fuel more easily diffuses than in the first mode.