Get cost-effective extended-range electric vehicles without changing the existing chassis structure of the car
A range extender generally refers to a component that provides additional electrical energy that causes the vehicle to travel a greater distance. A range extender in the traditional sense refers to a combination of an engine and a generator and an intelligent controller.
The biggest difference between the range extender and the engine is that it can always operate at its best and maintain the highest thermal efficiency.
The extended-range electric vehicle adopts a series hybrid structure which is a type of plug-in hybrid vehicle. The motor directly drives the vehicle, and the engine does not participate in the drive. When the battery is low, the extended-range engine works to generate electricity, and part of the generated electric energy is used to directly drive the motor, and the other part is to charge the battery. Semi-charged and half-discharged operation mode When the battery's power reaches a certain upper limit, the extended range engine stops working, and the battery directly drives the motor; as the travel time and mileage increase, the battery consumption becomes larger and larger, when the battery When the electric energy is lower than a certain lower limit, the extended range engine starts to work, and the subsequent extended range engine will always work in such a cycle state, and the start and stop of the extended range engine is completely dependent on the electric energy supply of the battery.
The range extender can also be seen as a reliable transition from hybrid drive to pure electric drive. In the common hybrid system, the engine is the main, and the electric motor is the supplement. The extended-range electric vehicle is mainly based on electric motors and supplemented by engines. The only role of the engine is to generate electricity.
The extended-range hybrid vehicle itself has basically the same principle as a pure electric vehicle, and can be externally charged. After the battery is fully charged, it can be used for a certain mileage. When the battery is low, the engine starts to charge the battery. The extended-range electric vehicle is completely the same as the pure electric vehicle, achieving zero emissions and zero pollution.
Ranger classification: According to the layout position: trailer type, plug-in type, vehicle type; according to the structure consists of: large capacity battery range extender, fuel cell range extender, engine generator set extender.
Specific working principle:
The range extender works by converting chemical energy into kinetic energy and then converting it into electrical energy. This part of the electrical energy is mainly to drive the motor and to charge the battery.
The controllers on general electric vehicles all come with a system that protects the battery. When only 30%-40% of the power is left, the ranger will detect the voltage shortage and start generating electricity. The range generator generates more electricity than the protection system. Therefore, the battery is not losing power at this time. When the battery is full, the range extender can also detect the battery voltage. The default is that the battery does not lose power. At this time, the range extender will reduce the power to the battery. Charge to prevent the battery from overheating the drum kit.
The key to electric vehicle owners' mileage-free anxiety is the range extender. The range extender is not new, and there are several cars in the domestic market, such as the BMW i3, the Chevrolet volt and the Buick Velite.
The model of the extended program has already topped the list in Japan, and Nissan's extended-sale small car "Note Epower" sold 73.38 million units in the Japanese market in the first half of this year.
The electric vehicle range extender is basically divided according to the power. The small range extender output power is below 1KW. Due to the small volume and power, it can be used for lead acid or lithium battery models of 800W and below (two rounds). Electric vehicles), as for the power and size of the range extender, are basically used in three- or four-wheel electric vehicles.
The performance of the range extender greatly affects the driving performance of the whole vehicle. Therefore, from the technical point of view, the range extender industry will have the following four trends.
First, the efficiency of energy conversion is further enhanced. In an electric vehicle with a range extender, the energy conversion efficiency cannot reach the level of a mechanically coupled hybrid vehicle model in the extended range mode, and there is a large room for improvement in this aspect.
Second, the range extender is effectively matched to the vehicle's powertrain. According to the vehicle parameters and design specifications, the performance of the range extender and the whole vehicle is matched, so that the range extender can select the low-power engine as much as possible to improve the fuel of the range extender. Economical, and make the battery as low as possible while satisfying the dynamic performance of the vehicle.
Third, the high-quality power generation of the range extender. At present, the types of starter/generator integrated motors for range extenders, including switched reluctance motors, asynchronous motors and permanent magnet brushless motors, are traditionally used in electric applications, and their applications in power generation are still new. Technology, how to issue dynamic and static performance, high efficiency, and meet the power requirements of the main drive motor power is worthy of in-depth study.
Finally, the overall structure of the range extender is optimized. The compact, compact design of the range extender that optimizes the overall configuration of the vehicle, engine and starter/generator motor is worthy of further study in order to obtain a cost-effective extended-range electric vehicle without changing the existing chassis structure of the vehicle.