How to get out of the measurement error of fuel dispensers

It is not ruled out that there are individual gas stations that are profit-seeking and use the tanker to maliciously cheat. However, after many years of investigations and handling by the quality supervision department, most gas station complaints were false complaints. The main reason for this was due to the driver’s unclear questions about the structure of the tanker, car fuel tanks, fuel gauges, and fuel consumption. Mao Zhiping, deputy director of the Municipal Quality Supervision Bureau, answered reporters' questions on refueling metering knowledge.

Reporter: What is the working principle of fuel dispensers? Are the fuel dispensers currently used at gas stations accurate?

Mao Zhiping: The fuel dispenser is a metered fuel volume device composed of oil pump, oil and gas separator, measuring transducer (flow meter), counter, indicating device, oil finder, oil gun and other major parts. Its working principle is: The motor-driven oil pump pumps the fuel in the oil storage tank into the oil-gas separator through the suction pipe and the filter, and separates the oil and gas. The fuel is input into the machine through the flow meter, the oil monitor and the oil gun under the pressure of the pump. Motor car. At present, gas stations are commonly used computer refueling machines using electronic counting display devices. Fuel refueling machines belong to the measuring instruments that are legally verified by the state and incorporated into key management, and the statutory metrological verification agencies impose compulsory verification on the refueling machines. The General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China (AQSIQ) has formulated the "Measures for Gas Station Metrology Supervision and Management" to regulate the measurement of gas stations.

According to the “Measurement Regulations for Fuel Tanker Calibration”, the accuracy of the tanker is ±0.3%, that is, 100 liters of fuel is added, and the actual volume should not be less than 99.7 liters. After regular inspection of the fuel tanker, its measurement is in line with the provisions in the “Measurement Regulations for Fuel Tanker Calibration”.

Reporter: Is it possible to accurately determine how much oil is added by using vehicle fuel tanks, fuel indication, and fuel consumption?

Mao Zhiping: The driver used to determine how much fuel is refueled. There are about three kinds of basis, namely, fuel tank capacity, fuel gauges, and mileage.

The fuel tank capacity on the car is the rated capacity of the fuel tank, which is usually given by the manufacturer as a technical parameter of the car. It refers to the safety capacity of the tank rather than the maximum capacity. According to the GB18296-2001 "Safety Performance Requirements and Test Methods for Automobile Fuel Tanks" national standard, the safety performance requirements for the fuel tank are "The rated capacity should be controlled at 95% of the maximum liquid capacity of the fuel tank," and the rated capacity is usually 85%-90 of the maximum capacity. About %, the excess space is reserved for the expansion of fuel due to the increase in temperature. Therefore, it is also possible that the fuel refueling amount is greater than the rated capacity of the tank. The owner can know the information about the maximum capacity of the fuel tank to the dealer or the designated maintenance point, and he knows what to do.

The fuel tank is equipped with a fuel gauge sensor assembly, and the sensor assembly mainly includes a buoy and a corresponding conversion circuit. The buoy floats on the surface of the oil and rises and falls as the liquid level rises and falls. The position of the liquid level is converted into the corresponding oil amount information through the conversion circuit and is displayed on the oil amount indication table. However, the oil meter is not a measuring instrument and cannot quantitatively display the amount of oil, and the operation is unstable, and it is easy to affect the accuracy due to irregular refueling operations. The oil quantity indication table can only qualitatively reflect the amount of remaining oil, and can roughly estimate the fullness of the fuel tank as a reference for judging when refueling is required. The fuel oil has been added to the overflow and the oil gauge indicator has not yet reached the top. The oil gauge shows that there is still one grid and the car has been anchored due to lack of oil. I believe many car owners have encountered or heard about it.

In addition, there are two kinds of understanding for the “full fill” of the tank. One is to add to the oil gun jumper and the other is to add to the tank port. Gas stations are all refueled with automatic refuelling guns. The deeper the refuelling gun is inserted into the fuel tank, the lesser the “full-up” volume is when the gun is thrown. The usual practice is for the refueling officer to put the gun after the oil gun jumps into the gun. Lift up a little and continue to refuel. According to our practice, the latter kind can sometimes add about one liter to the former. For the sake of safety, it is generally not advisable to fill the tank with oil.

The question of how many kilometers of oil can be added relates to the condition of the vehicle, driver's driving skills, road conditions, speed, load conditions, and temperature conditions. Skilled drivers are usually more fuel-efficient than novices. They drive on high-speed roads more than they do in the urban areas. The proportion of empty cars is fuel-efficient. They do not open air-conditioners to open air-conditioners and save fuel. Summertime is more fuel-efficient than winter. Therefore, simply judging whether a gas station is short-sizing or not is not reliable based solely on the relationship between the fuel quantity and the mileage.

Reporter: What should we pay attention to when refueling?

Mao Zhiping: First, we must refuel at reputable gas stations. The owner should judge according to his own experience, or according to the results of the relevant departments, choose reputable, business norms, oil quality and measurement are guaranteed gas station fixed point refueling, try to avoid gas station to their unfamiliar fuel. Second, check whether the tanker passes the metrological verification. The tanker that is in use must be subject to compulsory verification by the designated metrological verification agency, obtain the verification certificate and post it on the tank of the tanker before it can be used. The owner should pay attention to the date of verification and the effective date on the certificate, and avoid refueling on the overdue refueling machine. Third, observe the refueling staff's full refueling operations. Before refueling starts, observe whether the tanker's counter display is set to zero. When the quantitative pre-refueling, pay attention to observe each step of the refueler on the keyboard. Refuel officers are reminded to avoid filling the entire tank. Fourth, after the payment, invoices and other refueling vouchers should be obtained to provide evidence for the claim.