Carburetor-Integrated MAF Sensor for EFI Conversion
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Solution Overview
Problem
Existing mass-airflow rate measurement systems for internal combustion engine carburetors, particularly aftermarket EFI conversions, face challenges such as complex installation requirements due to sensitivity to air stream geometry changes and 'filling and emptying' effects in the intake manifold, which can lead to inaccurate fuel calibration.
Innovation Solution
A mass-airflow measurement conversion apparatus that uses multiple pressure sensors along the air intake path, an air temperature sensor, and a throttle position sensor, processed by a calculation section to generate a mass air flow rate signal, allowing for accurate measurement and compensation for manifold filling effects, thereby simplifying installation and improving calibration accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external MAF sensor is used for mass air determination in aftermarket EFI conversions, then the engine calibration effort is significantly reduced, but the installation complexity increases due to fitting and plumbing requirements and sensitivity to air stream geometry changes
Solution Approach 1:
The patent extracts the MAF sensor from the traditional external installation and relocates it to an internal position within the carburetor body. This extraction from the external environment eliminates the need for complex upstream and downstream plumbing while maintaining the measurement function, directly resolving the contradiction between measurement accuracy and installation complexity
Solution Approach 2:
The carburetor body is designed to serve multiple functions: it maintains its traditional fuel mixing role while simultaneously housing the MAF sensor and serving as the sensor's mounting structure. This multi-functionality eliminates the need for separate external mounting hardware and plumbing, reducing installation complexity while preserving measurement capabilities
2Measurement precision
If a MAF sensor is installed externally with proper plumbing, then accurate mass air flow measurement is achieved, but the original carburetor appearance is altered and additional duct work is required
Solution Approach 1:
The MAF sensor is nested within the carburetor body itself, with the sensor housing integrated into the carburetor structure. This nesting approach allows the measurement function to be contained within the existing carburetor form factor, preserving the original appearance while enabling accurate mass air flow measurement
3Device complexity
If traditional carburetion systems are used, then the installation is simple and appearance is maintained, but mass air flow measurement accuracy is insufficient for modern EFI conversions
Solution Approach 1:
The patent merges the MAF sensor integration with the carburetor body design, combining the measurement function with the existing fuel delivery structure. This merging allows the system to maintain the simplicity of carburetor installation while incorporating modern electronic measurement capabilities, resolving the contradiction between installation simplicity and measurement accuracy
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 solution provides a more accurate and simplified method for mass-airflow rate measurement, reducing installation complexity and maintaining the original appearance of the carburetor, while improving engine performance, drivability, and emissions.
Implementation Method 1
a plurality of pressure sensors disposed at different location along an air intake path of an internal combustion engine, each sensor adapted to sense a pressure of air flowing into the internal combustion engine and output an electrical signal as a pressure signal corresponding to the sensed air pressure
Implementation Method 2
an air temperature sensor disposed at an entrance to the air intake path and adapted to measure temperature of air entering the air intake path and output an electrical signal as a temperature signal corresponding to the sensed air temperature
Data Source
AI summary
A controller for an electronic fuel injection system for an internal combustion engine includes: a plurality of analog-to-digital (A/D) converters; a memory; and a processor communicatively coupled to the A/D converters and the memory. The A/D converters are configured to receive analog electrical signals representing pressures generated by a plurality of pressure sensors disposed at different locations along an air intake path and output corresponding digital signals representing the pressures, one or more of the pressure sensors are disposed in a body of a carburetor rendered permanently inoperable to mix fuel with air flowing in the air intake path, and the processor is configured to receive the digital signals representing the pressures output from the A/D converters and output a mass air flow signal representing a mass air flow rate as to an engine management system to control the electronic fuel injection system based on the received pressure signals.