1. Classification of Air Flow Sensors According to different methods of detecting intake air volume, air flow meters can be divided into two types: volumetric and mass. Among them, the volumetric type is divided into blade type, Kalman vortex type, and core type; Quality based air flow meters are divided into hot wire type and hot film type. Many cars such as Mercedes Benz, BMW, Volkswagen, etc. use hot film air flow meters. Early engine fuel injection systems were divided into two types: D-type (pressure type) and L-type (air flow type). The D-type fuel injection system does not have an air flow sensor. Figure 2-2 shows the basic control architecture of the D-type fuel injection system. Figure 2-4L Basic Control Architecture of Fuel Injection System for L-type Engine The fuel injection system for L-type engine (Figure 2-5) adopts a direct measurement method, which uses an air flow sensor to directly measure the air flow into the intake pipe. L-type sensors are divided into two types: volumetric flow sensors and mass flow sensors. Figure 2-5L Fuel Injection System Million Purchase Subsidy

2. What are the types of thermal gas flow meters

Thermal gas flow meters are mainly divided into four categories according to measurement principles and installation forms, which can adapt to different industrial scene needs. 1. The thermal distributed gas flowmeter adopts the principle of thermal conduction, and two temperature sensors are installed inside the pipeline: one measures the gas temperature, and the other generates a temperature difference through heating. The larger the gas flow rate, the smaller the temperature difference, thus calculating the flow rate value. Its advantages lie in its simple structure and low cost, but it should be noted that gas composition or temperature and pressure changes may affect measurement accuracy, making it more suitable for working conditions with stable composition. 2. Immersion thermal mass flowmeter sensors are directly inserted into the flowing gas to obtain flow data by measuring the rate at which the gas carries away heat. This type of equipment has industrial grade high precision, with a response time usually less than 1 second, and is particularly suitable for real-time monitoring of large-diameter pipelines, such as process gas flow control in chemical plants. When installing plug-in gas flow meters, there is no need to cut off the pipeline, and deployment is completed through flange components with probes. The probe is equipped with heating elements and temperature measurement modules, which have extremely low requirements for existing pipeline modifications and are easy to install and maintain online. This type of equipment is widely used in fields such as natural gas transmission and distribution, sewage treatment aeration systems, etc.

4. Thermal dissipation mass flow meters convert flow values by precisely controlling heating power and monitoring the degree of heat loss, with the core advantage being a repeatability error of less than ± 0.5%.

3. How to calibrate thermal mass flow meters

The core methods for calibrating thermal mass flow meters are divided into three categories, each sui

『SILVER Official Website SERVICE』