Engine Start Fuel Injection Control via Friction Torque Gradient
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Solution Overview
Problem
Existing methods for starting internal combustion engines during cold operations struggle to accurately adjust fuel vaporization, leading to excessive unburnt hydrocarbons and increased emissions due to variable fuel volatility, particularly in cold weather, as they fail to account for changes in engine friction torque.
Innovation Solution
A method that adapts the quantity of fuel injected based on the comparison between an engine speed gradient measured during a previous start-up and a reference gradient, corrected by the evolution of friction torque, allowing for more precise fuel vaporization control without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel injection quantity is calibrated for low volatility fuel (BPVR), then combustion is ensured, but unburnt hydrocarbons increase when high volatility fuel (HPVR) is used
Solution Approach 1:
The patent implements dynamic adjustment of fuel injection quantity based on real-time monitoring of engine speed gradient. The system transitions from static calibration to dynamic control by continuously comparing measured speed gradient against reference values and adjusting injection quantity accordingly, allowing adaptation to different fuel volatilities while maintaining reliable combustion
Solution Approach 2:
The system uses feedback control by measuring the engine speed gradient after fuel injection, comparing it with reference gradient values, and using this comparison to adjust subsequent fuel injection quantities. This closed-loop feedback mechanism enables the system to automatically compensate for fuel volatility variations and prevent excessive unburnt hydrocarbon emissions
2Reliability
If fuel injection quantity is increased to ensure sufficient vaporization, then combustion is improved, but excess fuel creates black smoke during cold start
Solution Approach 1:
The system dynamically adjusts fuel injection quantity based on measured engine speed gradient, which reflects actual vaporization conditions. By transitioning from fixed injection quantities to dynamic adjustment, the system optimizes fuel vaporization for reliable combustion while preventing excess fuel injection that would cause black smoke during cold start operations
3Device complexity
If fixed fuel injection calibration is used, then system complexity is reduced, but measurement precision of fuel volatility estimation deteriorates
Solution Approach 1:
The patent uses engine speed gradient as an intermediary parameter to indirectly measure fuel volatility. Instead of directly measuring volatile properties of fuel, the system monitors the engine speed response gradient after injection, which serves as a proxy indicator for fuel vaporization characteristics, enabling volatility estimation without complex direct measurement equipment
Solution Approach 2:
The system replaces complex chemical or physical measurement systems for direct fuel volatility assessment with a simpler mechanical measurement approach using engine speed gradient. By substituting direct fuel property measurement with engine response measurement, the system achieves accurate volatility estimation while maintaining low device complexity
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 improves engine start-up robustness and reduces pollutant emissions by ensuring a stoichiometric mixture, minimizing unburnt hydrocarbons and black smoke, even in cold conditions, by dynamically adjusting fuel injection based on friction torque variations.
Implementation Method 1
the quantity of fuel in gaseous form is well controlled
Data Source
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AI summary
The invention relates to a method for starting an internal combustion engine associated with means for adapting, during an engine start operation, an amount of fuel injected based on an estimation of the volatility (PVR) of the fuel based on the comparison between a gradient of the engine speed measured upon a preceding start operation and a reference gradient (1 10) corresponding to a predetermined fuel, characterised by the step (111) of correcting the reference gradient based on a change (?CMF) in the engine friction torque.