Internal Combustion Engine Fuel Injection Control for Alcohol Blend Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines using fuel containing alcohol face unstable combustion due to low cylinder temperatures before warming-up, as the vaporizability of fuel decreases, especially when injection occurs only in the second half of the compression stroke.
Innovation Solution
An internal combustion engine system with a control device that calculates and controls fuel injection in multiple crank angle sections, including the compression and intake strokes, based on cylinder temperature, alcohol concentration, and engine speed to ensure the fuel is injected when the cylinder temperature is above its boiling point, promoting vaporization and stabilizing combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cylinder injection is executed only in the second half of the compression stroke, then the device complexity is reduced, but combustion stability deteriorates when cylinder temperature is below fuel boiling point
Solution Approach 1:
The injection control device dynamically determines injection timing and duration based on real-time engine conditions (coolant temperature, alcohol concentration, engine speed, load). The control strategy adapts between different injection patterns: single-phase injection in compression stroke when temperature is sufficient, two-phase injection (compression + valve closed period) when temperature is low but injection amount is small, and three-phase injection (adding intake stroke) when injection amount is large, thereby maintaining combustion stability across varying conditions.
Solution Approach 2:
The system changes injection parameters (timing, duration, phase distribution) based on fuel properties and engine state. Specifically, it calculates injection timing to ensure fuel is injected when cylinder temperature exceeds fuel boiling point, and adjusts the distribution of injection across different strokes based on requested injection amount, thereby optimizing vaporization under different conditions.
2Reliability
If cylinder injection is executed in multiple strokes (compression, valve closed period, intake), then vaporization is improved, but the device complexity increases
Solution Approach 1:
The injection process is segmented into distinct phases (compression stroke, valve closed period, intake stroke) with specific injection amounts allocated to each phase based on engine conditions. The control device calculates and executes injection in each phase separately, allowing precise control over fuel distribution timing and location, thereby managing complexity through structured phase-based control.
Solution Approach 2:
The system dynamically selects which phases to inject into based on real-time conditions. Not all three phases are always active; the control device determines the appropriate combination of phases based on coolant temperature, alcohol concentration, and requested injection amount, thereby reducing unnecessary control complexity while maintaining combustion stability.
3Reliability
If fuel injection timing is advanced to promote vaporization, then combustion stability improves, but the risk of fuel sticking to surfaces increases
Solution Approach 1:
The system precisely controls injection timing parameters to target specific crank angle ranges where cylinder temperature exceeds fuel boiling point. By calculating optimal timing based on engine speed, load, and fuel properties, the system ensures fuel is injected at temperatures sufficient for immediate vaporization, preventing sticking while promoting stable combustion.
Solution Approach 2:
The injection strategy creates different local conditions in different phases: in the compression stroke, injection occurs during high-temperature adiabatic compression; in the valve closed period, injection occurs in the heated cylinder environment; in the intake stroke, injection occurs with fresh charge. Each phase provides locally optimized temperature and flow conditions to ensure vaporization without sticking.
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 ensures stable combustion by optimizing fuel injection timing and duration across various engine conditions, enhancing vaporization and reducing the risk of fuel sticking to surfaces within the cylinder.
Implementation Method 1
in a second half of a compression stroke in which gas is adiabatically compressed in the cylinder and a cylinder temperature increases
Data Source
AI summary
An internal combustion engine system includes an internal combustion engine including a cylinder, an intake valve and an exhaust valve, a cylinder injection valve, and a variable valve drive mechanism, and a control device that controls the cylinder injection valve and the variable valve drive mechanism. The control device includes a calculation unit that calculates a first crank angle section where a temperature of the cylinder is equal to or higher than a boiling point of the fuel in a compression stroke before completion of warming-up of the internal combustion engine and a second crank angle section where the temperature of the cylinder is equal to or higher than the boiling point of the fuel in the valve closed period, and an injection controller that executes fuel injection in the first and second crank angle sections by the cylinder injection valve.