In the real world, it is not easy to judge the performance of a car's fuel consumption. It is almost impossible to achieve absolute objective fairness. The reason is simple, because absolutely no two driving conditions will be the same! Therefore, official or factory-owned, the fuel consumption data they publish is actually an “ideal value.” In the real world, it is not easy to achieve such fuel consumption performance.
In general, although the standards vary from country to country, the methods for testing fuel consumption are almost the same - at least the principle is the same. Basically, three fuel consumption values will be tested, one is in urban areas, one is at 90 km/h at fixed speed, and the other is on highways. In some countries, the non-realistic 90km/h fixed-speed fuel consumption value is replaced by a mixed model of “urban+highway”. The test unit will first use a car to run the three driving conditions it wants to test. These driving modes will be connected to the computer through the fifth round and recorded on the tape or floppy disk.
After being sent to the testing unit, the test car submitted for inspection will be “tied” on the chassis power meter. There is a wheel on the chassis power meter. The wheels of the test vehicle are located on these wheels. The chassis power meter is controlled by a computer. When the driving status recorded on the magnetic tape or magnetic disk is input into the computer, the chassis power meter is moved. The test vehicle is passively carried by the chassis power meter and runs in place. It runs. The situation will be exactly the same as the driving condition recorded by the test unit at the time. It will be fueled, parked, and sometimes decelerated. The driving conditions are completely controlled by the transmission method on the magnetic disk. The purpose of this is to make the test conditions of all test vehicles consistent. Maintain the fairness of fuel consumption test data.
The official data or factory data of automobile fuel consumption is calculated in this way, and the transmission methods affecting fuel consumption performance will also be adjusted according to the progress of engine technology, environmental protection requirements, etc., and will be adjusted every few years. The direction of adjustment is definitely becoming increasingly stringent, and this has become the driving force for automakers to continue research and development.