Engine Fuel Delivery Control Using Temperature Offset
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Solution Overview
Problem
Small internal combustion engines lack cost-effective methods for controlling air-fuel mixtures and ignition timing, particularly without oxygen sensors or storage batteries, which are expensive and complex.
Innovation Solution
A method and system that includes determining peak power conditions, measuring engine temperature, comparing it to a known temperature, calculating an offset value, and adjusting the air-fuel mixture or ignition spark timing using a control module and power generation unit to optimize engine performance across various conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oxygen sensors or Lambda probes are used to indicate air-fuel ratio, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential measurement function from complex oxygen sensors and implements it through a simplified system using a heater and temperature sensor that measures exhaust gas temperature to infer air-fuel ratio, eliminating the need for expensive Lambda probes while maintaining measurement capability
Solution Approach 2:
The invention replaces expensive, complex oxygen sensors with inexpensive temperature sensing elements (thermocouples or RTDs) that can be easily replaced if needed, significantly reducing system cost while providing sufficient measurement precision for engine control applications
2Reliability
If a storage battery is used for the ignition system, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a self-service ignition system where the engine itself generates electrical energy through a magneto or alternator to power the ignition coil, eliminating the need for an external storage battery while maintaining reliable ignition function through self-generated electrical power
Solution Approach 2:
The ignition system is designed to serve multiple functions: the magneto/alternator not only provides ignition power but also charges the capacitor and can power auxiliary systems, reducing overall system complexity by eliminating dedicated battery components
3Power
If air-fuel mixture is enriched for peak power condition, then power output is improved, but fuel economy deteriorates
Solution Approach 1:
The patent implements dynamic air-fuel mixture control that adjusts the mixture ratio based on real-time engine operating conditions (load, speed, temperature), enriching the mixture only when peak power is required and using leaner mixtures during normal operation to optimize both power output and fuel economy
Solution Approach 2:
The system uses feedback from temperature sensors and engine performance monitoring to continuously adjust air-fuel mixture delivery, ensuring optimal mixture composition for current operating conditions rather than using a fixed rich mixture, thereby improving fuel economy while maintaining peak power capability when needed
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 efficient engine operation by adjusting the air-fuel mixture and ignition timing, improving performance, reducing emissions, and enhancing fuel economy across a wide range of operating conditions without the need for expensive sensors or batteries.
Implementation Method 1
sensing means including at least one thermocouple or RTD for sensing exhaust gas temperature
Implementation Method 2
sensing means including at least one thermocouple or RTD for sensing exhaust gas temperature
Implementation Method 3
a solenoid associated with the body and with one or more control passages through which fuel or air flow. The solenoid includes a valve that may be opened to permit communication between two or more passages and may be closed to prevent communication between said two or more passages
Implementation Method 4
In operation, a pressure differential causes liquid fuel to flow out of the fuel passages and into the air and fuel mixing passage where the fuel becomes mixed with air to create the air and fuel charge
Implementation Method 5
A choke valve is disposed in the air and fuel mixing passage near the upstream end to control a quantity of air flowing into the mixing passage during engine cold starting and warm up
Data Source
AI summary
A method of operating an engine is disclosed, which includes determining a peak power condition for the engine, measuring a temperature associated with the engine at said peak power condition, comparing the temperature measured with a previously determined temperature associated with a known peak power condition of the engine, determining an offset value based on the comparison made in step, controlling at least one of an air-fuel mixture delivered to the engine or ignition spark timing based on said offset value. Various engine fuel delivery systems, carburetors, fuel injection and control systems also are disclosed.