How to look at car fuel consumption, how should we count
The largest consumption of automobiles is fuel, so fuel economy has become one of the most important indicators of the economy of automobiles, and it is also one of the most concerned indicators for the majority of automotive consumers.
Fuel consumption testing methods mainly include the following:
Constant speed fuel consumption: 100 km fuel consumption when driving at a constant speed on a good road surface. A basic operating condition of a car running on a highway at constant speed. This fuel consumption is easy to measure, so it is widely used. For example, French and German regulations set the constant fuel consumption of 90 km/h and 120 km/h as the main fuel economy. index.
However, constant speed fuel consumption does not reflect the actual conditions of driving a variety of operating conditions and thus the fuel consumption value and actual fuel consumption have a greater difference, so foreign countries have increasingly widely used cyclic operating conditions method to determine fuel consumption.
The average fuel consumption under the limited conditions: the plain trunk road above Grade 3, with a length of not less than 50 kilometers, under normal traffic conditions, as far as possible to maintain a constant speed (60 kilometers for cars), and to test each time.
Road cycle fuel consumption: On a good road surface, the car travels according to the specified speed—the time specification. In order to make the fuel consumption close to the actual fuel consumption of the car under various typical driving conditions, urban circulation, suburban circulation, and interstate circulation are specified.
Car dynamometer cycle fuel consumption: The use of chassis dynamometer (drum test bench) in the indoor simulation of various conditions for testing. Such as ECE / EC test cycle, the city cycle includes idle, acceleration, uniform, deceleration conditions, three cycles, 200 seconds, four cycles, each cycle mileage of 1.013Kg; suburban conditions plus a variable speed driving 400 seconds.
In addition, there is a concept of economic speed, which is the minimum fuel consumption speed. The fuel consumption curve of a sedan is a shape with two ends curled up, that is, the fuel consumption is increased at low speed and high speed, and the fuel consumption is minimal at medium speed, generally 40 to 50 kilometers per hour. The fuel consumption curve of a jeep is a slowly rising straight line, that is, the higher the speed, the higher the fuel consumption. Of course, in addition to participating in the fuel-saving competition, it is rarely possible to use this speed for a long time. In actual driving, the car must constantly change operating conditions and often travel at more than economic speed, so the fuel consumption is higher than the value given by the manufacturer. In order to establish fuel consumption quotas, transport companies often use fuel consumption correction factors such as the increase in cargo turnover, cargo quality, roads, temperatures, altitude, and operating conditions.
The factors that affect fuel consumption are relatively complex, so paying attention to vehicle maintenance and nurturing good driving habits are the keys to vehicle fuel economy.
How to calculate the fuel consumption of a car
The fuel consumption of a car has a direct relationship with engine displacement. It is very difficult to accurately compare the fuel consumption of a vehicle because there are too many factors that affect fuel consumption. The same type, displacement, and age of a vehicle are comparable, and the driving conditions have a direct impact on fuel consumption. Accumulated feelings are the most accurate. The
For new cars,
Generally about 2 liters of displacement of the car, the city should be about 9 liters, about 7 liters of high-speed. The automatic transmission is about 10% more expensive than the manual transmission. The higher cross-country and SUV models of the vehicle body, due to the large windward area of the vehicle body, have a corresponding increase in wind resistance, and require more oil. The
For old cars of 5 to 6 years and 100,000 to 150,000 kilometers, it is reasonable to consume 5% to 10% more fuel per hundred kilometers than new cars of the same brand. It is reasonable that 10 to 200,000 kilometers of old cars in 10 years are more than 5% to 10% or even 20%.