What are the principles and diagnostic methods that need to be followed for the fault diagnosis of p

In the process of using pure electric vehicles, once a fault occurs, it will look for maintenance technicians to diagnose and repair the fault, and many maintenance personnel in the diagnosis of the fault, the most important thing is to use the long-term experience accumulation, according to some obvious symptoms when the fault occurs, to think and analyze, reasonably judge the cause of the failure, and then through their own series of experiments to carry out the verification and elimination of inference.

The use of such a diagnostic method is quite high requirements for maintenance technicians, not only to have solid professional knowledge and professional skills, but also to have many years of accumulated experience, good professionalism and related technical support. The technical support mentioned here mainly refers to the professional technical training and technical guidance of the manufacturers of pure electric vehicles, as well as the diagnostic tools, diagnostic instruments, and related maintenance guides for electric vehicles provided to maintenance personnel.

In addition, electric vehicle maintenance personnel should have a certain patience and careful work attitude, only with a high level of electric vehicle professionalism, in order to efficiently find the type and cause of electric vehicle failure, and correctly solve these faults, to ensure the recovery of the state of electric vehicles, normal driving.

For the diagnosis methods of electric vehicle failures, people often use the following methods: vehicle experiment method, empirical judgment fault diagnosis method, decoder diagnosis method and expert guidance diagnosis method.

With the continuous improvement of electric vehicle production technology and use technology, electric vehicle manufacturers will often conduct necessary technical training for technical personnel engaged in electric vehicle maintenance, so that they can master the new technologies, new methods of fault diagnosis and new fault handling methods used in the production of electric vehicles, so that maintenance personnel are not helpless in the face of new technical failures of electric vehicles, but can effectively deal with them with confidence.

Maintenance technicians have mastered certain maintenance knowledge and maintenance technology, and then conduct on-the-spot inspections of faulty electric vehicles, carefully study the performance of faults, and according to their own professional knowledge and practical experience, they can objectively find the causes of failures, and with the help of some professional fault detection equipment, effective detection, the search for the cause of the fault is much simpler and faster.

With the help of a decoder, the fault handling of the electric vehicle is determined, and finally the test run is carried out to check the health of the electric vehicle and determine whether the previous fault has really been eliminated. Practice has proved that as long as the maintenance technician adopts the correct diagnosis method and fault handling method, the fault will be quickly found and dealt with. The above operation is a common way in the current fault handling of pure electric vehicles, which is very useful and efficient for the maintenance of electric vehicles.

It is necessary to find the existence of specific problems, which can be diagnosed with such instruments, and when checking the fault, it is necessary to understand the basic problems of the car, and then find the appropriate maintenance method, and to understand the configuration standards of the electric vehicle.

The diagnosis method is that it can be diagnosed according to the fault, solved according to the problems that occur in the vehicle, diagnosed by the problems that appear, diagnosed according to some of the situations that are manifested, and can also be diagnosed through the introduction of the owner.

When a pure electric vehicle is repaired, it is necessary to check whether the power supply mechanism of the electric vehicle is normal. Electrification maintenance technology can be used to carry out inspections.

The long-term accumulation of experience in the building, according to the occurrence of the fault makes some obvious conditions, the cause of the fault is reasonably judged, and the diagnosis methods usually include vehicle experiment method, empirical judgment fault diagnosis method, decoder diagnosis method, and expert guidance diagnosis method.

(1) The vehicle enters the workshop.

2) Analyze the faults described by the user.

3) Connect the smart diagnostic device to the diagnostic socket of the vehicle.

4) Read the fault code and freeze-frame data, and record it. If there is a fault code related to the CAN communication system, then.

CAN communication should be checked and repaired first.

5) Clear the fault code.

6) Confirmation of fault symptoms. If the fault does not occur, the fault symptom simulation is carried out; If the fault rental is vertical, check the fault code and related.

Data stream. for information.

7) Conduct basic inspections and consult relevant information.

8) Fault diagnosis is carried out according to the fault phenomenon, fault code, related data flow and combined with other detection methods to find out the cause of the fault.

9) Troubleshooting.

10) Confirm troubleshooting.

1. Power battery failure.

Most of the ternary lithium batteries on the market are now used in 18650 models, 18 refers to the single cell 18 mm, 65 refers to the height of the single cell 65 mm, and 0 refers to the cylindrical cell. The advantage of ternary lithium battery is obvious, that is, the battery has a high energy density, which can reach 140wh kg. Let's do the math simply, for example, a 250kg battery can reach 35kWh of electricity.

The voltage of a single cell is generally that the voltage platform for our whole vehicle needs a certain number of cells in series. For example, if we string 96 single cells, then his voltage is. The power of each string of batteries is, then we are tied to 48 groups of cells, and the power of the whole vehicle at this time is.

2. DCDC converter.

DCDC DC converter is a low-voltage power supply platform that transforms the voltage of 345V into 12V. Because so far, many cars are 12V systems, and the 12V of the whole vehicle needs to be given to VCU, BMS, lights, glass regulators, central control screens, instruments, door locks, wipers, reversing images, pedestrian reminders, ABS systems, air conditioning control boxes, horns, electronic cigarette lighters, on-board chargers, motor controllers, fans, lead-acid batteries, and all other electrical appliances of the vehicle, so don't look at the DCDC voltage is not high, but the power is not low, it can reach left and right, or higher. The current is about 125A.

3. Motor controller.

As the main core component of the motor controlling the vehicle drive system, the motor controller is also one of the frequent failures. Mainly the output torque, target torque, speed and so on of the motor controller sometimes need to be calibrated, if the calibration is not correct, then there will often be some similar bus overcurrent, overvoltage, brake feedback failure, power limiting, etc., start-stop jitter speed is too high and so on.

<> above is the fault information that can be prompted by the fault lamp for reference.

Most of the faults of new energy vehicles refer to the faults of the three-electric system, which can be solved by professional physical stores, professionals, and special decoders and standardized operations.

The maintenance technology of pure electric vehicles is mainly manifested in the following aspects: First, the battery is prohibited from parking for a long time in a state of power loss. The main reason is that the battery will undergo a series of chemical reactions in a state of power loss.

Sulfation occurs, causing the product to adhere to the electrodes, resulting in a decrease in battery capacity [3]. Second, do a good job of carefully inspecting the battery. For pure electric vehicles, the battery is the core part of it, and various failures often occur.

If the battery fails, it can cause other parts of the car to fail. Therefore, it is necessary to do a good job in the regular inspection, maintenance and replacement of the battery to ensure that the motor is always in a normal operating state. In the inspection and maintenance of the controller, it is necessary to ensure the safety and reliability of the entire working environment in order to ensure the safety of the life and property of the staff.

Then special care should be taken not to disassemble the controller arbitrarily, and the wiring in the contactor cannot be replaced at will. Finally, keep the controller and its surroundings clean and tidy, and clean up dust regularly to prevent malfunctions.

<> above is a list of electric vehicle faults, which contains system faults, which you can use as a reference.