Fuel Quality Dependent Injection Timing Control
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Solution Overview
Problem
Existing methods for controlling direct fuel injection in internal combustion engines are limited in their ability to optimize engine operation across varying fuel qualities, particularly in reducing pollutant emissions and ensuring consistent performance across different speed and load ranges.
Innovation Solution
A method that determines a target value for the crank angle at which half of the fuel mass is burned (MFB50) based on fuel quality, using a two-part approach: the first part determines the target value from fuel quality parameters, and the second part adjusts the start of injection (SOI) to match this target, utilizing a predefined map and feedback signals from the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine operates with varying fuel qualities without detailed control, then the operation range is restricted and performance deteriorates, but implementing detailed control increases device complexity
Solution Approach 1:
The system performs preliminary determination of fuel quality parameters (cetane number, density, viscosity) before actual engine operation. Based on these pre-determined values, target MFB50 values are pre-calculated and stored in lookup tables. This preliminary preparation allows the control system to quickly retrieve appropriate target values during operation without performing complex real-time calculations, thus maintaining reliability while limiting the increase in control system complexity.
Solution Approach 2:
The patent replaces complex mechanical control adjustments with electronic control and software-based solutions. Instead of physically adjusting injection timing mechanisms for different fuel qualities, the system uses electronic sensors to detect fuel properties and software algorithms to calculate and retrieve optimal MFB50 target values from pre-computed lookup tables. This substitution of mechanical adjustment systems with electronic control reduces mechanical complexity while improving control precision and reliability.
2Reliability
If the engine restricts operation range to accommodate low quality fuel, then performance is maintained, but productivity decreases
Solution Approach 1:
The system dynamically adjusts the target MFB50 value based on real-time detection of fuel quality parameters and current engine operating conditions (speed and load). Rather than restricting the engine to a fixed limited operation range, the control system continuously adapts the injection timing target to match the actual fuel quality and operating point. This dynamic adaptation allows the engine to operate across a wide speed and load range while maintaining optimal performance and combustion efficiency regardless of fuel quality variations.
Solution Approach 2:
The patent changes the control parameter from fixed injection timing to variable MFB50 target values that are functions of fuel quality parameters (cetane number, density, viscosity), engine speed, and load. By making the injection timing parameter adaptive and dependent on multiple variables, the system expands the usable operation range. The control unit calculates appropriate MFB50 target values for any combination of fuel quality and operating conditions, enabling the engine to maintain optimal performance across the entire speed-load map rather than being restricted to limited operating bands.
3Object-affected harmful factors
If the engine uses traditional injection timing control, then device complexity is low, but pollutant emissions increase
Solution Approach 1:
The system implements a feedback control mechanism where the actual MFB50 value is continuously monitored and compared against the target MFB50 value derived from fuel quality parameters and operating conditions. The control unit calculates the deviation between actual and target values and adjusts the injection timing accordingly to minimize this deviation. This feedback loop ensures optimal combustion phasing that reduces pollutant emissions (NOx, soot, CO) while maintaining a relatively simple control architecture by using lookup tables for target value determination rather than complex real-time optimization algorithms.
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 precise control of engine operation, reducing pollutant emissions and ensuring optimal performance across different fuel qualities by adjusting the start of injection based on real-time fuel quality feedback, thereby reducing the need for restrictive operating conditions.
Implementation Method 1
the fuel is ignited by injecting the fuel directly into the combustion chamber after the gas contained therein has been compressed
Implementation Method 2
the fuel is ignited by injecting the fuel directly into the combustion chamber after the gas contained therein has been compressed
Implementation Method 3
using a pressure sensor within the combustion chamber
Data Source
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AI summary
A method for controlling an automotive internal combustion engine (1) having direct fuel injection is described, the method comprising a fuel adaption part in which a fuel quality parameter (F) is determined using a first fuel quality parameter determination procedure under predetermined conditions, and a control part which uses the value of a fuel combustion characteristics parameter (MFB50) derived from the fuel quality parameter (F) as a target value (αT) in a closed-loop control of the start of injection (SOl) at the engine (1), with the closed-loop control using a second fuel quality parameter determination procedure being different from the first fuel quality parameter determination procedure to determine an actual value (αA) of the fuel combustion characteristics parameter (MFB50).