Car With The Development Of The Heat Flow Meter

The method of acquiring the air flux of the main pressure pipelines through measuring the side branch air flux finds a new approach for large air flux measurement. This method is not only cost-efficient, simple to install and operate, but can be equipped with different small air flow meters- on the branch. To measure the intake air flux of the internal combustion engine by this method, efforts are made as follows:1. The author summarizes the development and the-state-of-the-art of application of the internal combustion engine electronic fuel injection system and air flow measurement technology, analyzes working principle and advantages and shortcomings of several different kinds of air flow meters. In the end, the author selected one kind of micro-bridge thermal mass airflow meter on the side branch by comparison.2. In order to calibrate the thermal mass air flow meter by the method of standard flow meter, this paper designs a suit of thermal flow meter's calibration test-bed. The micro-bridge mass airflow meter's output characteristic curves are achieved, and the author also analyzes the flow meter's temperature characteristics.3. The structure model of measuring the total air flux through measuring the side branch air flux is designed. For simplicity, the above designed structure model and the apparatus that process its signal output was named as partial flow thermal gas meter in this paper. In order to design partial flow thermal gas meter of different measuring range, the author also designed one kind of throttling device based on the standard orifice plate throttling device's design principle. Ultimately, two kinds of partial flow thermal gas meters and the corresponding two throttling devices with different diameters , I and II type, are designed in this paper.4. The paper presents an experimental study of the two kinds of partial flow thermal gas meter, the results show that the partial flow meter has the same output and temperature characteristics with the small thermal meter installed on the branch. But, the author finds the partial flow thermal gas meter's output signalsare instable when very small flux gas flow through the meter, which is one shortcoming of the partial flow thermal meter, it is necessary for us to study the problem further.5. Taking an experiment on the single-cylinder four-stroke engine SD1110 connected with the partial flow thermal gas meter directly, and monitoring the output waveform on the real time. Combined with the characteristic of the internal combustion engine's intake airflow, the paper analyzes the monitored waveform and puts forward to two solutions of measuring the pulsant airflow.