Fuel Injector Control Using L-Terminal Signal for OBD-II Compliance
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Solution Overview
Problem
The existing learning strategy for internal combustion engines is not OBD-II compliant, leading to inaccuracies in fuel injection, increased pollutant emissions, combustion noises, and vibrations, especially when injecting small fuel quantities.
Innovation Solution
A method that adjusts the fuel requested quantity by measuring electrical energy and engine speed, using a PWM signal's duty-cycle to calculate a reference value, ensuring compliance with OBD-II standards without modifying hardware or software, and incorporating a target value for mechanical energy to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the F-terminal signal is used for calculating the reference value of fuel requested quantity, then the learning procedure can be performed, but the diagnostic protocol is not OBD-II compliant
Solution Approach 1:
The patent introduces an intermediary approach by using the L-terminal signal (which is OBD-II compliant) as a substitute for the F-terminal signal (which is not OBD-II compliant). The L-terminal signal serves as a mediator that provides the necessary information for calculating the reference value while maintaining compatibility with OBD-II diagnostic protocols. This allows the learning procedure to function reliably without violating diagnostic standards.
Solution Approach 2:
The patent creates a copy or alternative representation of the F-terminal signal functionality using the L-terminal signal. Instead of directly using the non-compliant F-terminal signal, the system copies the essential information (duty-cycle values) from an OBD-II compliant source (L-terminal signal) to perform the same calculation function, thereby achieving both reliability and compliance.
2Measurement precision
If the fuel requested quantity is adjusted by closed-loop controlling engine speed, then fuel injection accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the engine speed is continuously monitored and used to adjust the fuel requested quantity. The closed-loop control system compares the actual engine speed with the target speed and modifies the fuel injection accordingly. This feedback approach improves fuel injection accuracy by compensating for variations in injector performance while managing system complexity through efficient control algorithms.
3Object-generated harmful factors
If small fuel quantities are injected, then emission control is improved, but injection accuracy deteriorates due to production spread and tolerances
Solution Approach 1:
The patent uses feedback control to compensate for the reduced accuracy inherent in small fuel quantity injections. By continuously monitoring engine speed and comparing it with target values, the system can detect and correct deviations caused by production tolerances and injector variations. This allows small fuel quantities (such as pilot injections) to be injected with sufficient accuracy, thereby controlling emissions while maintaining precision through active correction.
Data Source
AI summary
A method of operating an internal combustion engine, and more particularly a fuel injector is disclosed. The fuel injector is commanded to inject a fuel requested quantity. The fuel requested quantity is adjusted by closed-loop for controlling an engine speed to match a target value thereof. A value of a first parameter indicative of an amount of electrical energy supplied to an electric battery by an electric generator coupled to the internal combustion engine is measured. A value of a voltage generated by the electric battery and a value of the engine speed are measured. A reference value of the fuel requested quantity is calculated on the basis of the voltage value, the engine speed value and the value of the first parameter. A difference between the value of the adjusted fuel requested quantity and the reference value is calculated and used to control the internal combustion engine.