What speed is the most fuel efficient?
Many people wonder: Does driving speed affect fuel consumption and what speed is the most fuel-efficient?
For motorbikes
Many people think that driving a motorbike at slow speed will save more fuel than driving at high speed. However, this is considered a misconception because technical experts believe that all slow-moving vehicles waste fuel.
The reason why driving too slowly (from 5 - 20 km/h) does not save fuel is because the engine rotates at 1,000 - 3,000 rpm while the car is in low gear (slow running) corresponding to a larger number of engine revolutions per km, more fuel is pumped in and burned for each rotation cycle. In addition, when driving slowly, the centrifugal shaft will not operate to connect the wheel movement, causing fuel waste.
At higher speeds, the bike shifts into a higher gear but the engine revs still between 1,000 and 3,000 rpm. The engine turns less per kilometer and uses less fuel. However, when you go slow, there is less air resistance, while going fast increases the resistance.
A car going 80 km/h will have 8 times more air resistance than a car going 40 km/h. Doubling the speed will quadruple the air resistance. So the engine will have to work harder to overcome the air resistance. That is why going fast does not save fuel.
Therefore, the average speed recommended by the manufacturer for popular vehicles (100cc - 150cc) is 40-60km/h. At that time, the wind resistance is not large and the engine shifts to a higher gear for a more optimal km/revolution index. In addition, when traveling on inner-city roads, you should choose a less congested section of road, even if it is a little further than a heavily congested section.
For cars
The most fuel-efficient speed for a car depends on many factors, for example, smaller cars with better aerodynamic designs will be more fuel-efficient at high speeds than trucks or larger cars in general.
Many people think that the best fuel-efficient driving technique is to drive slowly. However, similar to motorbikes, this is not actually beneficial.
Because when driving slowly, the engine speed is still at 1,000 - 3,000 rpm, the car shifts to a low gear, the number of engine revolutions per km will be greater. Conversely, when driving fast, the car shifts to a high gear, the engine speed is at 1,000 - 3,000 rpm, the number of engine revolutions per km is lower.
But driving fast has a disadvantage: there is more air resistance than driving slowly. When air resistance increases, the engine has to work harder to overcome this resistance. This means more fuel is consumed. When the speed of the car is doubled, the air resistance will increase by four times.
Therefore, driving at low or high speed is not the way to save gas. The most accurate way to save gas is to keep the car at medium speed. Because at this time, the car can shift to a higher gear but also does not have to endure large air resistance. According to experts, maintaining a speed of 48 - 80 km/h is considered the best way to save gas.