Fuel Injection Control for Small Engine Emissions
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Solution Overview
Problem
Small internal combustion engines face challenges in meeting exhaust gas emission legislation due to the high cost and complexity of sophisticated fuel injection systems, which are not economically viable for these applications, leading to coarse fuel control and inefficiencies.
Innovation Solution
A method of fuel injection that uses an injector to deliver a set amount of fuel, with control strategies that calculate and adjust the number of operations per engine cycle based on engine speed and load, allowing for finer control by aggregating fuel demand over multiple cycles, thereby reducing fuel wastage and improving efficiency without increasing system complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sophisticated fuel injection system is used, then fuel delivery precision and emission control improve, but system cost and complexity increase
Solution Approach 1:
The patent segments the fuel injection control into multiple discrete operations within each engine cycle. Instead of continuous control, the system divides fuel delivery into a series of discrete injector activations, where each activation delivers a predetermined fuel amount. This segmentation allows precise fuel metering through simple on/off control signals rather than complex analog control systems.
Solution Approach 2:
The patent employs periodic action by activating the fuel injector in repeated cycles within each engine operating cycle. The controller commands the injector to operate multiple times at specific intervals, delivering fuel in periodic pulses. This periodic activation pattern enables precise fuel dosing through time-based control rather than complex flow regulation mechanisms.
2Object-generated harmful factors
If a sophisticated fuel injection system is used, then emission compliance improves, but system cost increases
Solution Approach 1:
The patent segments fuel delivery into discrete operational steps, where the controller determines the number of injector activations needed to meet emission requirements. By dividing fuel delivery into countable units, the system achieves precise fuel metering for emission compliance using simple digital counting logic rather than expensive continuous control systems.
Solution Approach 2:
The patent implements self-service through the predetermined fuel amount mechanism. The injector is designed to deliver a fixed, known amount of fuel per activation, eliminating the need for complex flow sensors or feedback control systems. The controller simply counts activations to determine total fuel delivery, allowing the system to self-regulate fuel quantity without additional expensive components.
3Device complexity
If the injector operates a set number of times per cycle, then system simplicity is maintained, but fuel control precision deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the optimal number of injector activations for various engine operating conditions. The controller uses lookup tables or pre-programmed logic to determine the exact number of times the injector should operate based on sensed engine parameters, eliminating the need for complex real-time calculations while maintaining precise fuel control.
Solution Approach 2:
The patent implements dynamics by making the number of injector activations variable based on engine operating conditions. Rather than a fixed number of operations, the system dynamically adjusts the activation count based on engine load, speed, and other parameters, allowing precise fuel control across varying operating conditions while maintaining simple discrete control logic.
Data Source
AI summary
A method of operating an internal combustion engine. With reference to FIG. 1, fuel is supplied to charge air using an injector (116) which in each operation delivers a set amount of fuel. The amount of fuel supplied to the charge air in each engine cycle is controlled by how many times the injector (116) operates in each cycle. A desired fuel demand is calculated as a number of operations of the injector per cycle, calculated to at least one decimal place. The desired fuel demand is rounded to a near integer to provide an output fuel demand for the injector as a number of operations of the injector for the next operating cycle in varying operating conditions of the engine. The controller calculates an aggregate number of operations for a plurality of engine cycles which is closer to an aggregated desired fuel demand for the plurality of cycles than if for each cycle of the plurality of output cycles the output fuel demand is calculated independently.