Is direct engine drive really fuel efficient? Uncover the advantages and principles of range extende

Mondo Cars Updated on 2024-02-02

In the development process of new energy vehicles, extended-range electric vehicles and plug-in hybrid vehicles are two different technical routes, each with its own advantages and disadvantages, and each has its own supporters. However, some people believe that the fuel consumption of extended-range electric vehicles must be higher than that of plug-in hybrids, because extended-range electric vehicles cannot realize that the engine directly drives the wheels, but has to go through multi-stage transmission such as generators, batteries, and electric motors, which will cause energy loss. Is this view correct? Today, we will tell you the truth and uncover the mystery of fuel consumption of extended-range electric vehicles and plug-in hybrids.

First of all, we need to understand that the biggest difference between a range-extended electric vehicle and a plug-in hybrid is that the engine of a range-extended electric vehicle is only used to generate electricity and is not involved in the drive, while the engine of a plug-in hybrid can both generate electricity and directly drive the wheels. In this way, the powertrain of a range-extender electric vehicle is simpler and requires only a generator and a drive motor, while the powertrain of a plug-in hybrid is more complex and requires a generator, a drive motor, as well as a gearbox and a differential. This means that the power system of the extended-range electric vehicle has advantages in terms of weight, volume, cost, and maintenance, while the power system of the plug-in hybrid vehicle has advantages in terms of efficiency, dynamics, and driving experience.

Secondly, we must know that the fuel consumption of extended-range electric vehicles and plug-in hybrids is not a fixed value, but depends on a variety of factors, such as the capacity of the battery, the charging and discharging efficiency of the battery, the thermal efficiency of the engine, the conversion efficiency of the generator, the conversion efficiency of the electric motor, the weight of the vehicle, the air resistance of the vehicle, the rolling resistance of the vehicle, the driving conditions, the driving habits, and so on. Therefore, to compare the fuel consumption of extended-range electric vehicles and plug-in hybrids, it is necessary to consider different situations, such as urban conditions, high-speed conditions, comprehensive conditions, etc.

So, how does the fuel consumption of range-extended electric vehicles and plug-in hybrids perform under different operating conditions? We can analyze it based on some data.

In urban conditions, the fuel consumption advantage of extended-range electric vehicles is more obvious. Because urban conditions are characterized by low speed, multiple stops and walks, and frequent acceleration and deceleration, this will cause the fuel economy of traditional engines to be very poor, while the fuel economy of electric motors is very good, because electric motors can achieve efficient energy**. Therefore, the extended-range electric vehicle can make full use of the electric energy of the battery in urban conditions, reduce the number of engine starts and working time, and thus reduce fuel consumption. The plug-in hybrid vehicle can also use the electric energy of the battery in urban working conditions, but because the capacity of the battery is limited, it still needs the assistance of the engine, and the start and stop of the engine will also cause energy loss, so the fuel consumption is relatively high. According to some data, the fuel consumption of extended-range electric vehicles per 100 kilometers in urban conditions is about 15 liters, while the fuel consumption of a plug-in hybrid is about 2 per 100 kilometers in urban conditionsAbout 5 liters.

At high speeds, plug-in hybrids have a more pronounced fuel consumption advantage. Because the characteristics of high-speed working conditions are high speed, stability, and less acceleration and deceleration, this will cause the fuel economy of the motor to be very poor, because the energy of the motor is very small, and the electric energy of the battery will be exhausted quickly, and the engine needs to be supplemented. Therefore, the plug-in hybrid vehicle can realize the engine directly driving the wheels under high-speed conditions, the transmission efficiency is higher, and the engine can work in the optimal combustion efficiency range, thereby reducing fuel consumption. In high-speed working conditions, the extended-range electric vehicle cannot directly drive the wheels of the engine, but has to go through multi-stage transmission such as generators, batteries, and motors, which will cause energy loss, so the fuel consumption is relatively high. According to some data, the fuel consumption of plug-in hybrids is about 4 per 100 kilometers at high speedsAbout 5 liters, while the fuel consumption of extended-range electric vehicles in high-speed conditions is about 6 per 100 kilometersAbout 5 liters.

In the comprehensive working conditions, there is not much difference between the fuel consumption of extended-range electric vehicles and plug-in hybrids. Because the combined operating conditions are the average of urban operating conditions and high-speed operating conditions, the advantages and disadvantages of range-extended electric vehicles and plug-in hybrids will also cancel each other, and the fuel consumption performance will also be similar. According to some data, the fuel consumption of extended-range electric vehicles per 100 kilometers under comprehensive working conditions is about 3It is about 5 liters, while the fuel consumption of plug-in hybrid vehicles is about 3 per 100 kilometers under comprehensive working conditions0 liters or so.

To sum up, we can see that the fuel consumption of range-extended electric vehicles and plug-in hybrids is not static, but changes with changing operating conditions. In urban conditions, the fuel consumption of extended-range electric vehicles is lower, while in high-speed conditions, plug-in hybrids have lower fuel consumption, and in comprehensive conditions, the difference between the two is not large. Therefore, we cannot generalize that the fuel consumption of extended-range electric vehicles must be higher than that of plug-in hybrid vehicles, but we must choose a suitable technical route according to their actual needs and usage.

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