Engine Control Device Cylinder Wall Temperature Fuel Adhesion
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Solution Overview
Problem
The existing control devices for internal combustion engines with direct fuel injection fail to effectively manage fuel adhesion to the cylinder wall surface due to variations in cylinder wall surface temperature and heat transfer characteristics during transient operating conditions, such as engine startup or deceleration, leading to increased unburned hydrocarbons in exhaust gases.
Innovation Solution
An internal combustion engine control device that calculates the cylinder wall surface temperature based on cylinder pressure and uses this real-time data to adjust fuel injection timing, number of injections, and split injection ratios to minimize fuel adhesion, incorporating a wall surface temperature calculation unit and a combustion control unit to optimize combustion parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fuel is directly injected into the cylinder to cool the air-fuel mixture and suppress knocking, then thermal efficiency is improved, but fuel adhesion to the cylinder wall surface increases and unburned hydrocarbons in exhaust gas increase
Solution Approach 1:
The system performs preliminary heating of the cylinder wall surface before main fuel injection by injecting a small amount of fuel beforehand. This preliminary action raises the wall surface temperature to prevent excessive fuel adhesion during the main injection, thereby reducing unburned hydrocarbons while maintaining the thermal efficiency benefits of direct injection
Solution Approach 2:
The system uses periodic post-injection of fuel after the main combustion event to maintain cylinder wall temperature and prevent fuel adhesion. This periodic action creates a cycle of heating and cooling that prevents continuous fuel accumulation on the walls, reducing unburned hydrocarbon emissions while preserving the cooling effect during main injection
2Measurement precision
If the cylinder wall surface temperature is low during transient operations, then fuel adhesion to the wall surface increases, but the existing control system using only intake air temperature and cooling water temperature cannot accurately detect the actual wall surface temperature
Solution Approach 1:
The system replaces traditional temperature sensors with an in-cylinder pressure sensor to indirectly measure wall surface temperature. By analyzing pressure variations during the compression and expansion strokes, the system calculates wall surface temperature without direct thermal contact, enabling accurate detection during transient operations where conventional temperature sensors respond too slowly
Solution Approach 2:
The system uses in-cylinder pressure as an intermediary parameter to infer wall surface temperature. The pressure sensor detects pressure changes caused by heat transfer between the cylinder wall and gas, allowing the ECU to calculate actual wall surface temperature and adjust fuel injection accordingly, preventing fuel adhesion during transient conditions
3Adaptability or versatility
If the EGR rate varies during operation, then the composition and temperature of post-combustion gas vary, causing cylinder wall surface temperature to fluctuate, but the existing map-based control cannot adapt to these variations
Solution Approach 1:
The system implements continuous feedback control by monitoring in-cylinder pressure to detect actual wall surface temperature and adjusting fuel injection parameters in real-time. This feedback mechanism allows the system to adapt to EGR rate variations and other transient conditions, maintaining optimal wall surface temperature and preventing fuel adhesion regardless of changing operating conditions
Solution Approach 2:
The system transitions from static map-based control to dynamic adaptive control. By continuously calculating wall surface temperature from pressure data and adjusting injection timing and quantity accordingly, the system dynamically adapts to EGR variations and transient operations, maintaining temperature stability and preventing fuel adhesion under varying conditions
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 allows for real-time control of fuel injection and combustion parameters, reducing fuel adhesion to the cylinder wall and improving combustion efficiency, thereby minimizing unburned hydrocarbons and optimizing engine performance during transient operations.
Implementation Method 1
an in-cylinder pressure sensor 19 that measures a pressure in the cylinder 15
Implementation Method 2
a wall surface temperature calculation unit 201 that calculates a wall surface temperature of the cylinder 15 based on the pressure in the cylinder 15
Implementation Method 3
a direct injection technique of injecting fuel directly into a cylinder. Since the fuel is directly injected into the cylinder, the air-fuel mixture is cooled by vaporization heat of the fuel
Implementation Method 4
a heat transfer coefficient between the post-combustion gas and the wall surface also varies every cycle
Data Source
AI summary
Provided is a technique capable of suppressing the amount of fuel adhering to a wall surface of a cylinder in an engine whose wall surface temperature varies every cycle. An internal combustion engine control device that controls an internal combustion engine, which injects fuel into a cylinder and generates combustion by ignition, includes: a wall surface temperature calculation unit that calculates a wall surface temperature of the cylinder based on a pressure in the cylinder; and a combustion control unit that controls the combustion of the internal combustion engine based on the calculated wall surface temperature.