[0016] Such as figure 1 As shown, the drive system of a series hybrid vehicle includes an engine, a first motor (used as a generator), an inverter, and a battery connected in sequence, and a second motor (used as a motor) connected to the battery through the inverter The second motor is connected to the wheels through a speed change mechanism (not shown) to provide power for the vehicle to drive it to travel. The vehicle controller can control the engine, the first motor, and the second motor at the same time, and control their start and stop. In addition, the battery can also be charged by the power supply.
[0017] The driving method of a series hybrid vehicle provided by the present invention includes: driving a vehicle in a driving state, wherein, when the battery charge is greater than a lower limit threshold and the acceleration is not greater than the upper limit acceleration, the battery supplies power to the motor to drive the motor The vehicle is running and the engine is not working; when the battery charge is less than the lower limit threshold or the acceleration is greater than the upper limit acceleration, the engine is started to drive the generator to generate electricity.
[0018] For ease of description, the vehicle is divided into 5 working modes, namely, pure electric mode, series mode, full load mode, brake feedback mode and portable charging mode.
[0019] The following will refer to figure 2 The shown flow illustrates the working steps of the method provided by the present invention.
[0020] According to the method of the present invention, when the vehicle starts, the vehicle controller will first read the battery charge (SOC) and determine whether the SOC value is greater than the lower threshold. If the SOC value is greater than the lower threshold, the vehicle uses the battery as the second motor When the SOC value is greater than the lower limit threshold, and the speed changes smoothly, that is, the acceleration is not greater than the upper limit acceleration, the vehicle still only uses The battery is powered and driven by the second motor, which is still a pure electric mode. The energy flow of the pure electric mode is as Figure 3A Shown.
[0021] According to the method of the present invention, when the SOC value is less than the lower limit threshold or the acceleration is greater than the upper limit acceleration, the engine will be started to drive the generator to generate electricity. But there is a difference between the two. When the SOC value is less than the lower threshold and the acceleration is not large, the battery needs to be charged and the vehicle also needs a power source, then the engine is started, the engine drives the generator to generate power to the motor, and the motor drives the vehicle to travel, and The generator charges the battery. This mode is called series mode, and its energy flows like Figure 3B Shown. When the SOC value reaches the upper charging threshold, the vehicle will exit the series mode and switch to pure electric mode operation. When the SOC value is not less than the lower limit threshold but the acceleration is greater than the upper limit acceleration, the battery cannot meet the needs of the vehicle and the engine needs to be started. Then the battery is used to power the motor while the engine is used to drive the generator. The power generation supplies power to the electric motor, which drives the vehicle. This mode is called full load mode operation, and its energy flows like Figure 3C Shown. When the acceleration decreases, the vehicle will exit the full load mode and switch to pure electric mode operation.
[0022] According to the method of the present invention, when the vehicle is in a running state, when the acceleration is greater than the feedback acceleration and is negative, if the battery charge is less than the upper threshold, the motor converts the mechanical energy generated by braking into electrical energy and stores it in the battery. If the battery charge is greater than the upper threshold, the battery can no longer be charged at this time, and the mechanical energy is not converted. This working mode in the braking phase is called the brake feedback mode. When the speed changes smoothly, the mode is pushed out, and its energy flows like Figure 3D Shown.
[0023] According to the method of the present invention, when the vehicle is at a standstill, the battery is charged by the power source. This mode is called the portable charging mode, and its energy flows like Figure 3E Shown.
[0024] Generally speaking, overcharge and overdischarge of the battery have an adverse effect on the life of the battery. In the method of the present invention, the lower threshold is the lower SOC value of battery discharge; the upper threshold is the upper SOC value of battery charging, which is used to limit whether to enter the brake feedback mode when braking, both of which are based on battery charging Based on characteristics, for example, the lower threshold may be 5% to 10%, and the upper threshold may be 90% to 95%. The upper limit acceleration is related to the battery used in the electric vehicle. The size of the discharge current of the battery and the duration of high current discharge determine the maximum output power that the battery can provide, and the range of the upper limit acceleration can be calculated accordingly. Calculated according to the batteries commonly used in the field at present, the range of the upper limit acceleration is 2.3-2.5 m/s 2 That is to say, when the vehicle's forward acceleration exceeds this range, the vehicle should enter the full load mode to meet the output power demand. The feedback acceleration corresponds to the acceleration when a sudden brake occurs, generally greater than or equal to 2.6 m/s 2 , Which means that when the reverse acceleration of the vehicle is not less than 2.6 m/s 2 When the time, the vehicle should enter the brake feedback mode in order to recover the braking energy, thereby increasing the driving range of the vehicle.
[0025] Preferably, in the method of the present invention, a set threshold is used instead of the upper threshold for battery charging as the actual limit threshold for the engine to drive the generator to charge the battery. The actual limit threshold is the same for the unit time before the current charge. Or similar mileage, or the average value of multiple charges during the same time. Its value is determined by the vehicle controller through self-learning of the accumulated battery power consumption. Generally speaking, it is far less than the upper limit of battery charging threshold determined by the battery characteristics, so as to maximize the use of electricity and reduce the use Fuel, to achieve the best fuel economy.
[0026]The method for determining the actual limit threshold will be described below through examples. For example, for office workers, their daily driving route is basically fixed, roughly the distance from home to the company, and their energy consumption and distance are regular, so that the car owner is in the process of returning (assuming that the distance is a little far away, and the battery is not enough Round trip use) will start the engine to start generating electricity when the battery power reaches the lower threshold. However, if the power generation is stopped until the battery power reaches the upper threshold, there may be a large amount of battery power remaining when the vehicle is parked. At this time, the entire vehicle on the car The controller will record the SOC value of the battery during parking (set to SOC5), SOC5-lower threshold + on-road loss = power generation = engine power x power generation time, so you can calculate the approximate amount of charge required during the return journey. This value is added After the lower limit threshold is SOC6, that is to say, when returning, you only need the engine to drive the generator to charge the battery to SOC6 and you can get home. After multiple recordings (the number of times is N) the value of SOC6, the vehicle controller takes the average value and After saving the value in the memory, the vehicle controller will control the engine to drive the generator to charge the battery only to SOC6, so as to maximize the use of the battery and use less fuel. If the driving distance changes for a long time, the vehicle controller will re-record the SOC6 value according to the actual situation; if the driving distance temporarily changes, when the SOC value is less than the lower threshold, the vehicle will enter the series mode again. Based on the above requirements, the multiple charging capacity is stored in the memory of the vehicle controller.
[0027] The drive system for a series hybrid vehicle provided by the present invention includes an acceleration sensor, a power measurement device, a vehicle controller, an engine, a generator, an inverter, an electric motor, and a battery. The motor is connected to the battery in sequence, and the motor is connected to the battery through the inverter and connected to the wheels through the speed change mechanism to drive the vehicle. Among them, the acceleration sensor is connected to the vehicle controller to measure the acceleration of the vehicle and send the acceleration To the vehicle controller; the power measurement device is connected with the battery and the vehicle controller to measure the battery charge and send the power to the vehicle controller; the vehicle controller is used to receive the acceleration and the acceleration measured by the acceleration sensor The battery charge is measured by the power measurement device, and the acceleration and battery charge are compared with their respective thresholds. When the battery charge is greater than the lower threshold and the acceleration is not greater than the upper acceleration, the battery is controlled to provide power to the motor to drive the vehicle. , And keep the engine off; when the battery charge is less than the lower limit threshold or the acceleration is greater than the upper limit acceleration, the engine is started to drive the generator to generate electricity.
[0028] Preferably, the vehicle controller is also used to start the engine when the battery charge is less than the lower limit threshold, the engine drives the generator to generate electricity to supply power to the motor, the motor drives the vehicle to travel, and the generator charges the battery.
[0029] Preferably, the upper limit threshold of the battery charging is the average value of the same or similar mileage in a unit time, or the average value of multiple times of charging for the same time before the current charging. The multiple charging capacity is stored in the vehicle controller.
[0030] Preferably, the system further includes a motor state switching device, the vehicle controller is also used for when the acceleration is greater than the feedback acceleration and is negative, if the battery charge is less than the upper threshold, the device will switch the motor to the generating state to brake The generated mechanical energy is converted into electrical energy and stored in the battery.
[0031] For the motor, it can double as an engine and a motor, which is controlled by the motor controller. The motor state switching device is a device that enables the motor controller to perform the motor state switching, which can be connected to an acceleration sensor The switch controlled by the comparator may also be a switch controlled by the driver of the vehicle.
[0032] Preferably, the vehicle controller is also used for when the acceleration is greater than the upper limit acceleration, while the battery is used to power the motor, the engine is started to drive the generator to generate power for the motor, and the motor drives the vehicle.
[0033] The acceleration sensor of the system of the present invention can use various acceleration sensors known in the art, such as photoelectric type, mercury type, differential transformer type and semiconductor type, etc., and can be installed at the position of the vehicle, generally in the luggage of the vehicle. In the cabin or in the engine compartment.
[0034] The electric quantity measuring device, vehicle controller, engine, generator, inverter, electric motor, and battery of the system of the present invention are well known to those skilled in the art, and various electric quantity measuring devices, vehicle controllers, engines, and generators can be used. The specific structure of the machine, inverter, motor and battery will not be repeated.
