I want to change trams, but I run more at high speed. Considering the high power consumption at high speed and the need to buy trams, I want to ask Miss Xia, what is the reason for the sharp increase in power consumption at high speed? Is it because the wind resistance increases or the efficiency of the motor decreases at high speed?
A: If the high-speed mileage accounts for a large proportion, my suggestion is to consider buying hybrid power, plug in or not. Of course, plug in experience is more abundant, such as stronger power performance and more scenarios of using pure electric driving. If you live in a city, especially if the proportion of driving time in the city is more than 70%, then plug-in hybrid can play a great role, and it can also let you enjoy the treatment of new energy vehicles. In addition, it avoids the problem of low electric efficiency when running at high speed. Note, however, that this does not include incremental power. Because its fuel engine cannot be driven directly, it can only generate electricity, and can’t avoid the problem of low electric efficiency when running at high speed.
When driving at high speed, the power consumption increases, mainly because the efficiency decreases when the speed of the motor is high, which is similar to that of the internal combustion engine. Electric vehicles usually have a transmission ratio, that is, a direct gear, which makes the speed of the motor increase linearly with the speed of the vehicle. Unlike the fuel engine, the speed can be adjusted by gear. Even if the vehicle speed is high, the engine speed can be reduced to less than 2000 rpm. The higher the driving speed of the vehicle, the greater the reaction of air resistance. Multi-gear allows the fuel engine to use fuel more efficiently. The electric car has only one gear. If it is efficient at low speed, it will only be inefficient at high speed. In the general ledger, the proportion of low-speed and medium-speed application scenarios is larger. When setting the transmission ratio of the only gear, we can only focus in this direction.
However, for the motor, its speed range for maintaining power performance is wide enough, and it is not necessary to equip with multi-shift transmission. At present, the Porsche Taycan is also equipped with two-gear transmission on the rear axle. Another thing is the weight. Electric vehicles often weigh 300~400 kilograms more than the same fuel vehicles, which can not be ignored for the additional energy consumption. Therefore, the balance of plug-in hybrid shows its value, especially the electric power of electric vehicles is not really green now.