Hello everyone, I'm Xiao Li. I used to hear old drivers say that if we want to save fuel, you will drive at high speed, and whether a car is good or not, you will know it after you get on the highway. But many people will find that our daily scooters are not necessarily fuel-efficient when they are on the highway, and the fuel consumption of some cars will be relatively high when they run at high speeds, but some cars will be particularly fuel-efficient after they are on the highway. My own main scooter has always been a small displacement model, said that the displacement is not particularly small, anyway 1.5 liters of standard, ordinary family cars are this displacement, until the large displacement of the car on the highway to know the secret of high-speed fuel saving.
In fact, if you drive a large displacement car to the city, although its speed is not high, the performance of the engine has not been brought into play, and the engine is in a state where it cannot be used, and this kind of car is more fuel-intensive when running in the city. For example, if a big man himself carries 100 pounds of things to the 3rd floor at one time, then he will feel tired after carrying 1000 pounds of things to the 3rd floor, but he will not feel very desolate and tired, right? But if you only let him carry 50 pounds each time, then he will double the number of times he climbs the stairs, although he carries relatively light things, but climbing the stairs itself is very tiring, and doubling the number of stairs climbing for him is that he has no strength to make it, and he will definitely be more tired and consume more physical strength.
In fact, the larger the displacement of the engine, the more powerful it is, so the engine will rev lower when maintaining high speeds. If you want to pull the car to a speed of 120 km/h, then you have to pull the engine up to the maximum power output as close as possible to achieve this goal. But the higher the speed, the more intense the engine burns, and the faster the engine burns, the faster the fuel injection, right? At this time, the car burns more oil, and the following two pictures are the speed performance of the car with different displacements in my hand at the same speed at high speed.
Figure 1
Figure 2
WE CAN SEE THAT IN THE FIRST PICTURE, WHEN MAINTAINING A SPEED OF 110KM/H, ITS ROTATION SPEED IS ONLY ABOUT 2100, BUT IN THE SECOND PICTURE, IT ALSO MAINTAINS A SPEED OF ABOUT 110KM/H, AND THE ROTATION SPEED RUNS TO ABOUT 3100. There is a minimum speed difference of 1000 rpm between the two cars. But both cars have the same speed at their maximum power, both at 6200 rpm. The car in the first picture has a displacement of 1.8, while the car in the second picture has a displacement of 1.5 liters.
In this case, it is obvious that the car corresponding to the first picture has lower fuel consumption when driving at a speed of 110 km/h, and the car corresponding to the second picture has a higher engine combustion because it has higher speeds. It needs to consume more oil, so it consumes more fuel.
Therefore, it is not that all cars can save fuel after going to high speed, the secret of fuel saving on high speed is that the displacement of the engine should be large, and the faster the speed of the car with a small displacement, the greater the fuel consumption, but some large displacement cars are still within the economic speed range even if they are driven at the highest speed limit. Since many people don't know how to judge the economic speed of their car, I will share my experience in judging the economic speed of the car with you.
I have told you before, you will divide the maximum power output of the engine into three parts, generally when we drive on the national highway, the gearbox does not go up to the highest gear, but the speed is always controlled in the first third of the range, at this time the fuel consumption of the car is much lower than the urban area, right? When the engine speed exceeds one-third and does not exceed two-thirds, it is generally when we need to overtake and step on the accelerator deeply, and the fuel consumption at this time must be relatively large.
For example, the maximum engine output of my car above is 6200 rpm, and about 2000 rpm when I am about a third of the time, but when I want to overtake, I usually step on 2800 or even 3,000 rpm. WHEN MY CAR RUNS 110KM/H, IT IS ITS ECONOMIC SPEED. When driving a 2.5L Toyota Camry, when it runs to 120KM/H, his speed is only about 1800 rpm, and the maximum power output speed of this car is 6600 rpm, which means that this car is still in its economic speed range when driving 120KM/H, so can it not save fuel?
In general, the large-displacement car, after the high-speed run, according to the regular speed, this time is the closest to its economic speed, this is the large-displacement car on the high-speed after the secret of fuel-saving. But after you get on the high-speed of a small-displacement car, if you run at the regular speed, the engine will already howl, and the economic speed exceeding it is too much, so it is not fuel-efficient.