How to calculate the fuel consumption of a car How to calculate the fuel consumption of a car
Many car owners are puzzled by the fuel consumption value of a hundred kilometers provided by automobile manufacturers: Why is the fuel consumption of my vehicle always larger than this value? To understand this problem, we must first understand the meaning and measurement method of this value.
At present, the world's commentary on the fuel economy of vehicles is generally expressed in terms of fuel consumption or oil mileage. For fuel consumption representation, the smaller the value, the better the fuel economy; for the oil mileage representation, the larger the value, the better the fuel economy (converted relationship: 1 gallon = 4.546L, 1 mile = 1.609km).
There are two methods for determining the fuel economy of a car: one is a driving test method; the other is a constant speed fuel consumption test on a flat road and under certain conditions.
The fuel consumption of a constant speed 100 km fuel consumption vehicle at constant speed on a smooth road with no slope is equal to 100 km fuel consumption. The so-called constant speed also includes the case of driving at constant speed at different speeds. The constant speed driving at different speeds and the fuel consumption per 100 kilometers are different.
Select a section of flat concrete or asphalt pavement with no slope, and the car will drive at the same speed at the highest speed and at different speeds (take one point every 10km/h) at constant speed. Impact of slope), note the fuel consumption, you can get 100 km fuel consumption at different speeds, the so-called constant speed 100 km fuel consumption. Its shape is generally two high middle concave.
The fuel consumption of one of the vehicle speeds is the lowest, and the vehicle speed is called the economic speed. If the manufacturer indicates that the fuel consumption of a certain type of vehicle is 4.5L/100km, it usually refers to the 100km fuel consumption of the vehicle that is the most fuel-efficient at the economical speed. In fact, this kind of fuel consumption index will never be reached in your driving on weekdays.
The fuel consumption of the cycle due to constant speed fuel consumption and actual driving conditions are very different, in fact can not fully assess the car's fuel economy. Nowadays, cycle fuel consumption is generally used to assess the fuel economy of a car. The cycle fuel consumption refers to the fuel consumption when the vehicle is traveling under different set conditions within a specified section of a typical road. At least three kinds of operating conditions including constant speed, acceleration and deceleration must be stipulated, and the complicated ones should be counted as start and idle stop. A variety of conditions, and then converted into 100 kilometers of fuel consumption. For example, China has six operating conditions cycle fuel consumption (trucks) and the city's four operating conditions cycle fuel consumption (passenger), Europe has ECE-R15 operating cycle fuel consumption, the United States has a road cycle and city cycle fuel consumption.
The urban fuel consumption and highway fuel consumption given by modern cars are more comprehensive. It should be the comprehensive fuel consumption of the city and the comprehensive fuel consumption of highways. It is also referred to as the urban cycle fuel consumption and the road cycle fuel consumption. In China, it is more simply called urban fuel consumption and highway fuel consumption.