The dashboard shows that the fuel consumption per 100 kilometers is 7L. In fact, it seems to be 9L, or even 10L. How is the manufacturer cheating? Got a fun table to sell his car?
How is the apparent fuel consumption calculated?
By calculating the working time of the fuel injector, the fuel consumption is obtained. First of all, we need to know how the apparent fuel consumption is calculated. Zhang Baoyuan and others published a paper "Testing and Research on Fuel Consumption Accuracy of Automobile Instruments" in Beijing Automotive magazine. It says that the total fuel injection can be obtained by the working time of the injector, and then divided by the mileage to get the average fuel consumption.
Incorrect fuel consumption is a common phenomenon.
It seems that the data is available and the calculation should be accurate, but the actual situation shows that the phenomenon of inaccurate fuel consumption is very common.
In the previous paper, four cars were tested, and the results showed that the fuel consumption was 5% to 9% lower than the actual fuel consumption. Li Haibin of Nanjing University of Science and Technology's master thesis "Study on the Influencing Factors of Customer Satisfaction with Automobile Fuel Economy in China Market of F Company", in which the actual fuel consumption of eight different models was tested.
According to the amount of fuel added at the gas station, divided by the mileage, it is found that the apparent fuel consumption of eight vehicles is lower than the actual fuel consumption by 1% to 9. 1%, which is a floating interval. Therefore, if the actual fuel consumption per 100 kilometers is 8L, the apparent fuel consumption will generally be around 7.2L to 7.9L. ..
The difference is that the manufacturer deliberately reduced the apparent fuel consumption.
It stands to reason that the new car can be more accurate. Why is the difference so big? If the car has been aging for a long time, or the technical level was limited at that time, the sensor was not good, and the measured fuel consumption was not accurate, which is understandable.
However, the apparent fuel consumption of many new models is much lower, which is really tricky. Because now the error can be made very small technically, otherwise the rocket can still send satellites?
Kun Hailin of Jilin University and others published a paper in Automobile Engine, an experimental study on the relationship between injection pulse width and fuel consumption quality of electronically controlled gasoline engines. It is concluded that the method of calculating fuel consumption according to the working time of injector can make the error within 65438 0%, which is very accurate.
What "optimizations" have manufacturers made?
Therefore, if the new car shows low fuel consumption, it is generally the manufacturer's intention to reduce it. How to do it specifically? For example, if the actual speed is replaced by the apparent speed, the mileage used for calculation will be higher than the actual mileage and the apparent fuel consumption will be lower.
Just like we go to a new gym to work out, the speed and kilometers on the treadmill are empty targets. Pay attention, really.
After running 10km, I don't feel very tired. Will there be "physical strength getting better?" , this illusion.
The American Automobile Association (AAA) has a report, "Accuracy of Estimating Fuel Consumption". It says: the reason why some models have low fuel consumption is that mileage is not allowed. China's national standard GB 15082-2008 "Automobile Speedometer" stipulates that the speed displayed by the speedometer shall not be lower than the actual speed. According to the calculation formula, when the actual speed is 100km/h, if the error is the largest, the dashboard can display 1 14km/h at most.
If the fuel consumption is 8L, the apparent fuel consumption becomes 7L, with a difference of1L.. If it is cleaned regularly, the probability of inaccuracy will be higher. There is also a method of 1, that is, when the fuel consumption is high, it is beautified by algorithm adjustment and theoretical fuel consumption. If you are used to cleaning up fuel consumption regularly, the probability of inaccurate fuel consumption will be higher.
Refer to Ding Jiajun's paper "Research on Computer Algorithm and Software Realization of Automobile Instrument Cluster Drive Based on CAN Bus" published in Auto Parts magazine. It says: When the fuel consumption has just been cleared, the car stops and stops, and the fuel consumption is relatively high, the instrument will be adjusted by adding the theoretical fuel consumption algorithm.
Usually, after 1 month, the actual fuel consumption will completely replace the beautified data of the algorithm. 1 Cars with a theoretical fuel consumption of about 6L stop and go in urban areas, and it is normal to exceed 10L. Therefore, it is not impossible that there is a difference of 2 to 3L between the apparent fuel consumption and the actual fuel consumption in a short time after cleaning.
What can I do to know the real fuel consumption?
What can I do to know the real fuel consumption of the car? The most accurate method is to measure the exact mileage with GPS positioning, and then go to the gas station to fill it up and see how much oil is used. The amount of oil taken is divided by the actual kilometers and multiplied by 100, which is more accurate, and the fuel consumption per 100 kilometers.
But most friends can't record mileage with high-precision GPS every day, can they? So it is obviously more realistic and convenient to refer to the odometer directly. If you want to know the long-term fuel consumption, you can also use some apps that record fuel consumption. Every time you refuel, you can enter the number of kilometers and the amount of oil, and the fuel consumption per 100 kilometers will be directly displayed.
Common is low apparent fuel consumption.
Generally speaking, low fuel consumption is actually very common. Don't worry about the car breaking down. It is likely that the manufacturer is doing something bad. You can refer to it appropriately, and don't think it must be accurate, especially when it is just cleared, the error will generally be relatively large.