We all know that the average fuel economy of a car increases when we're stuck in a traffic jam in the city because a lot of the fuel is used for idling. In fact, there will be a relationship between the speed and fuel consumption, the relationship is when the speed up to a certain speed, fuel consumption will reach the optimal value, is called the economic speed, and when the vehicle passed the economic speed, speed and then go up fuel consumption will increase.

       Economic speed is when the vehicle is running at this speed, the speed of the vehicle and engine resistance to reach an optimal value, can make the average fuel consumption of the vehicle to the minimum, generally speaking, the greater the displacement of the car economy speed will be higher, because the power base is large, the more easy to push the vehicle.

      Suppose that the economic speed of a 1.3 displacement mini van may be in the 50 to 60km/h, and then the need to use the speed to pull, because the power itself is not enough, plus the body resistance is large, so the 120km/h when the fuel consumption is much higher than the 60km/h, sometimes even more than half.

       And some of the big power car, such as my own audi A6L 2.8 liter, when open to 50 RPM to 1000 RPM, speed can not economy, at the time of open until around 100, RPM to 1500 RPM, I personally feel that time is one of the most fuel efficient, so if I'm in the speed limit of 100 km/h in the highway, table of fuel consumption can be reduced to 7 l / 100 km, and if it is in the highway speed limit of 120 km/h, table show fuel consumption will rise to more than 8 litres, if again drive a bit faster and even more than 9 litres, This is the relationship between a car's speed and its fuel consumption.

       For motorcycles, the same is true, when the motorcycle will also have an economic speed, for example, a simple example: the same 120km/h high-speed cruise, chunfeng 650NK will be more fuel efficient than suzuki GW250, but in the city at low speed when the fuel consumption of GW250 will be more fuel efficient than chunfeng 650.

     This explains in the motorcycle inside, also be the model with bigger power economy hour is higher, but when exceed economy hour hind, the faster the car speed is faster the meeting of oil consumption is higher. Suzuki GW250 economic speed of about 70 km/h, in this life can reach almost 400 kilometers per hour, but if is 120 km/h cruise, rotational speed can reach more than 8000 r/min, almost 200 kilometers oil started to flash, thus it can be seen in the motorcycle, and after more than economic speed faster the more fuel.

       To sum up, for internal combustion engine, the faster the speed needed to fuel injection quantity will be higher, and some of the power is not car but only have speed, is enough to run fast, so after more than economic speed, the faster the speed, the more fuel-efficient vehicles, but when the speed more than economic speed will speed the closer economic speed will be more fuel-efficient.