Automobile Inspection Technology

Chapter 25 Vehicle Inspection Technology (1)
ST knowledge points
1. The type, setting and testing items of the vehicle inspection station;
2. The detection principle and detection method of automobile power and economy;
3. Detection methods and requirements of vehicle sideslip;

4. Test items and detection methods of automobile braking performance;
5. Vehicle exhaust pollution components, emission standards and testing methods;
6. Detection of car noise and headlights.

Learn
1. Understand the basic settings, testing items and testing procedures of the vehicle testing station;
2. Master the main testing items and methods of automobile power and economy;

3. Master the detection standards and common detection methods of vehicle sideslip and braking performance;
4. Master the main detection methods of automobile exhaust pollution; understand the emission inspection standards of gasoline and diesel vehicles;
5. Master the basic detection methods of car noise and car headlights;
6. Understand the speedometer detection and body electronic detection technology.

(Section [-]) Vehicle Inspection Station
Automobile inspection station is an institution that comprehensively uses modern inspection technology to carry out non-disintegration inspection and diagnosis of automobiles.It has modern testing equipment and testing methods, and can detect various performance parameters of the vehicle indoors, providing a basis for comprehensive and ready evaluation of the performance and technical status of the vehicle.

The motor vehicle inspection station is entrusted by the relevant state authorities (public security or transportation department), according to the relevant laws, regulations and standards of the state, conducts performance inspections on motor vehicles without disassembly.The detection line refers to the detection system composed of several detection equipment arranged in sequence.The testing station generally includes one or several testing lines depending on its function and scale.According to the different functions of the testing stations, the testing stations can be divided into safety and environmental protection performance testing stations, comprehensive performance testing stations and automobile maintenance testing stations, which are respectively managed by the public security department and the transportation department.

[-]. Types and functions of vehicle testing stations
1. Automobile Safety Inspection Station
According to the requirements of relevant policies and regulations, the vehicle safety and environmental performance testing station has the following basic testing functions:
(1) Initial inspection

Article 17 of the "Regulations on Road Traffic Management of the People's Republic of China" stipulates that a vehicle must pass the inspection of the vehicle management agency, obtain a number plate and a driving permit before it is allowed to drive. "So before using the car, the car owner must first go to the inspection station designated by the vehicle management department to conduct an initial inspection of the car. After passing the inspection, he can apply for registration, receive a license plate, driving license and other procedures.

The purpose of the initial inspection is to ensure the legitimacy of the source of the car, and to ensure that the technical performance of the car must meet the requirements of the relevant state regulations.The basis of the current technical inspection is mainly the national standard "Motor Vehicle Operation Safety Technical Conditions KGB7258-2004) and other standards.

(2) Regular inspection

Regular inspection means that in-use cars must regularly go to designated inspection stations for safety technology inspections in accordance with the requirements of the public security department.Many countries have requirements for regular inspections of in-use vehicles.Through regular inspection, technical problems can be found in time.Any vehicle that fails to pass the inspection is not allowed to go on the road and must be adjusted or repaired.

At present, under normal circumstances in our country, it is stipulated that automobiles are inspected once a year, which is also called annual automobile inspection.In some cases, inspections may be required several times a year.

(3) Temporary inspection

In addition to regular inspections, in some cases cars are subject to ad-hoc inspections.E.g:
① When a new car or modified car receives a temporary license plate;

② When the motor vehicle is used again after being left unused for a long time;
③The motor vehicle is seriously damaged, after repair and before going on the road;
④ When foreign and foreign vehicles are approved to drive in my country for a short period of time;

⑤Other circumstances stipulated by the vehicle management department (such as operating vehicles during the freight period), etc.

(4) Special inspection

This refers to inspections performed under special circumstances for special purposes.For example, the inspection of modified vehicles, accident vehicles, chief executive vehicles or foreign affairs vehicles.The content and requirements of such inspections are often different from those of general inspections.For example, for modified vehicles, in addition to the necessary inspections according to the regulations, special performance (such as sealing, heat insulation, etc.) must also be checked. Handling stability and safety performance, etc.

According to the provisions of GB21861-2008 motor vehicle safety technical inspection items and methods, the inspection methods and inspection items of the safety technical inspection of motor vehicles with four or more wheels (except wheeled special mechanical vehicles) are shown in Table 5-1.

2. Automobile comprehensive performance testing station
The vehicle comprehensive performance testing station is a technical service organization for comprehensive performance technical supervision and testing, vehicle maintenance quality supervision and testing, and vehicle performance diagnosis of road transport vehicles. It is an important technical base for road transport management agencies to engage in road transport management.The Ministry of Communications' "Administrative Measures for Vehicle Comprehensive Performance Testing Stations in the Automobile Transportation Industry" (Ministry Order No. 29) has made detailed regulations on the construction, management, responsibilities, basic conditions, and identification of automobile comprehensive performance testing stations. Legal basis for site management.

(1) Functions of testing station
The vehicle comprehensive performance testing station is a testing station under the management of the traffic management department.It is mainly used for the supervision and comprehensive performance inspection of the technical condition of the transport vehicles.According to the Ministry of Communications Order No. 1991 in 29, the main tasks of the comprehensive performance testing station are:

① Check and diagnose the technical status of the transport vehicles in use.

② Carry out quality inspection on maintenance vehicles in the automobile maintenance industry.

③Accept the entrustment to test the vehicle modification, transformation, scrapping and related new processes, new technologies, new products, scientific research achievements and other items, and provide the test results.

④Accept the entrustment of the departments of public security, environmental protection, commodity inspection, metrology and insurance, etc., to carry out the inspection of relevant items and provide the inspection results.

It can be seen that the function of the comprehensive performance testing station is stronger than that of the safety-environmental protection testing station, and it is also a technically authoritative inspection department.

According to the national standard "General Technical Conditions for Automobile Comprehensive Performance Testing Stations KGB/T17993-1999), comprehensive performance testing stations can be divided into A and B levels according to their functions.

A-level station: A comprehensive performance testing station for vehicles that can undertake testing of vehicle technical conditions, vehicle technical level assessment, maintenance quality testing, and testing of vehicles and related items entrusted by relevant departments.

Class B station: an automobile comprehensive performance inspection station that can undertake automobile technical condition inspection and maintenance quality inspection.It can be seen that among the two-level detection stations of A and B, the function of the A-level station is stronger.

(2) Testing items and equipment requirements
See Table 5-2 for the testing items and equipment requirements of the comprehensive performance testing station.

3. Automobile maintenance inspection station
Automobile repair and inspection stations refer to inspection stations established by automobile transport enterprises or maintenance enterprises to provide professional services for automobile maintenance.The vehicle maintenance testing station mainly focuses on vehicle performance testing and fault diagnosis. By performing technical status testing and fault diagnosis before vehicle maintenance, it can determine additional operations, minor repair items, and whether the vehicle needs major repairs; Technical testing and diagnosis can monitor the quality of car maintenance.

[-]. The composition of the safety inspection station and its station layout

1. Test content and use equipment
(1) Test items and equipment used
According to the requirements of the national standard "Motor Vehicle Operation Safety Technical Conditions KGB7258-2004), the main testing items of the safety and environmental performance testing station are as follows:

① Appearance inspection.It is a manual inspection item, which can be roughly divided into on-vehicle and under-vehicle inspections, mainly including:

a. The appearance of the vehicle, such as whether the sprayed characters are in good condition, whether the license plate complies with the regulations, etc.

b. Whether various lights, rearview mirrors, wipers, horns, instruments and other equipment are complete and reliable.

c. The sealing condition of the cab and the compartment, whether the opening and closing of the doors and windows, and the lifting and lowering of the glass of the doors and windows are normal.

d. Whether the free travel of the steering wheel, clutch and brake pedal meets the requirements.

e. Leakage of oil, water, electricity and gas systems.
.
Whether the parts of the steering system, brake system and transmission system are connected firmly and rotate flexibly.

g. Whether the front and rear axles, transmission shafts, frame and other devices are obviously broken, damaged or deformed.

h. Whether the connection of exhaust pipe, muffler, fuel tank, battery, shock absorber, cooling fan, etc. is reliable.

② Front wheel sideslip.Use a skid test bench to check the amount of front wheel skid.

③ Axle load measurement.Use an axle load gauge to measure the axle load (sometimes an axle load gauge is combined with a brake test stand).

④Brake inspection.Use the brake test bench to test the braking force of each wheel.

⑤ Check the speedometer.Check the prompt error of the speedometer on the speedometer test bench, and calibrate the speedometer.

⑥ noise measurement.Use a sound level meter to measure interior noise and horn sound levels.

⑦ Inspection of headlights.Use the headlight tester to detect the luminous intensity and irradiation direction of the headlight, mainly to measure the high beam.

⑧Exhaust pollutant detection.Gasoline engines use exhaust gas analyzers to detect the content of C0, HC, C02, O02 and N0 in the exhaust gas of automobiles; diesel engines use smoke meters to check the exhaust smoke.

(2) Layout of testing stations
A general detection line has 3-5 stations, too few stations, and low detection efficiency; too many stations, the detection line is too long, and occupies too much land.In order to improve the detection efficiency, several detection items can be detected at one station at the same time, but at the same time, the time used for the detection of each station should be approximately the same.In addition, there are sequential requirements among some testing items, such as weighing the axle must be carried out before measuring the brake.Since a lot of exhaust gas needs to be removed when testing exhaust, smoke and vehicle speed, and the noise is relatively large, the testing of these items should not be arranged in the middle of the testing line as much as possible.

At present, the layout of the detection line introduced in my country generally includes: the appearance inspection station on the upper part of the car body, called L station (Lamps and Safety Device Inspection), and the side slip brake speedometer station, called ABS station (A-alignment, side Sliding test bench; B-braketester, brake test bench; S-speedometer, speedometer test bench), light exhaust station, called HX station (H-headlight, headlight tester; X-exhaustagstester, exhaust gas analysis instrument), the bottom inspection station is called P station (pitinspection trench inspection).The inspection of the bottom of the vehicle should set up a trench.Figure 5-1 shows the layout of the four-station safety detection line.Among them, the first station is the vehicle declaration and appearance inspection station, the second station is the ABS and noise inspection station, the third station is the HX station, and the fourth station is the vehicle bottom inspection and result printing station.

Manual and semi-automatic safety inspection lines generally combine appearance inspection and vehicle bottom inspection into one station, and three stations are set up.The five stations are generally the car data input and safety device inspection station, ABS station, HX station, P station, comprehensive judgment and main control room station.As shown in Figure 5-2, the domestic five-station automatic safety inspection line is shown.

Regardless of the number of stations in the safety and environmental protection inspection line, because the inspection items are fixed, in order to facilitate the flow operation, they are all arranged in a straight channel type to improve the inspection efficiency.

2. Detection process

The process flow of manual and automatic safety and environmental protection testing lines is shown in Figure 5-3 and Figure 5-4.

As shown in Figure 5-2, the five-station detection layout, the detection process is as follows:
(1) Car data input and L station
According to the indication of the incoming line indicator light, when the light is green, the detection line of the vehicle under inspection stops at the first station.According to the driving license and the inspection form, the registration staff will input the relevant information of the vehicle into the population computer.The input information includes: license plate number, engine number, chassis number, brand model, vehicle owner, fuel type, headlight system (two lights or three lights), driving mode, vehicle condition (new car or in use), inspection type ( Initial inspection or annual inspection), inspection frequency, etc.The inspectors shall carry out the visual inspection of the upper part of the vehicle according to the specified items. At this time, the driver shall operate according to the prompter of the inspection program at L station and cooperate with the inspectors in the inspection.The inspection results are entered into the computer by the registrant.These data will be sent to the main control computer, as long as there is an unqualified item, the main control computer will judge that the safety device inspection is unqualified, and the result will be displayed on the inspection program indicator.When there is no car at the second station, the prompter will display the word "advance".When the car drives away, the photosensitive switch is blocked, and the incoming line prompt light turns green to notify the next car to enter.

(2) ABS and noise inspection station

①Let the car pass the sideslip test bench at low speed along the ground marking line.When passing, the car should be perpendicular to the side skateboard, and the steering wheel cannot be turned.After passing, the main control computer will also judge whether it is qualified or not, and the result will be displayed on the second station indicator.

②Drive the vehicle onto the axle load gauge or wheel load gauge to measure the axle load.

③ Drive the front wheels onto the brake test bench to measure the braking force of the front axle.Press the brake pedal to the bottom according to the prompt of the position indicator, and the maximum braking force of the left and right wheels can be measured.If unqualified, it is allowed to test again.

④ Drive the rear wheel onto the brake test stand, and press the brake pedal according to the indicator.The indicator will indicate the result of the rear brake test.If unqualified, it is allowed to test again.

⑤ Tighten the parking brake and detect the maximum braking force of the left and right wheels (only detect the axle connected to the parking brake).

⑥ Drive the wheel connected to the speedometer on the speedometer test stand, and the driver holds the test switch.Put the gear lever in the highest gear, step on the accelerator pedal slowly according to the instructions of the inspection program indicator, and press the test button when the car is evenly accelerated to 40km/h (the value indicated by the speedometer in the cab).After the main control computer judges whether it is qualified or not, the result is displayed on the indicator.If unqualified, it is allowed to test again.

⑦ Press the horn for about 2 times according to the prompt, or measure the noise inside the car as required. After the test is completed, the prompter will display the test result.

It should be noted that the location of the driving wheel of the car and the installation location of the parking brake are different, and the detection procedures are also different:
a. Rear drive, rear parking.Front brake, rear brake, parking brake, speedometer.

b. Front drive, front parking.Front brake, parking brake, speedometer, rear brake.

c. Front drive, rear parking.Front brake, speedometer, rear brake, and parking brake.

When the indicator prompts "forward", the car can be driven to the next station.

(3) HX station
① Park the car on the parking line at a certain distance (generally 3m) away from the headlight detector according to the instruction of the guide indicator, and pay attention to keep it perpendicular to the guide rail of the headlight detector.Turn on the high beam according to the instruction of the indicator, and the headlight detector will automatically drive out to detect the luminous intensity and the direction of the optical axis of the left and right high beam respectively.The detection result is displayed on the indicator.If one of the left and right headlights is unqualified, the comprehensive judgment of the headlights is unqualified.

② When testing a gasoline engine, insert the probe of the exhaust gas analyzer into the exhaust pipe of an idling car according to the instructions of the guide indicator, and take a gas sample, and the indicator will display the test result after a few seconds.When testing the diesel engine, insert the probe of the smoke meter into the exhaust pipe of the car to the specified depth according to the instruction of the guide indicator, and then press the accelerator pedal to the bottom quickly under the idling state according to the instruction, and do four free accelerations.The average value of the next three test data by the computer is used as the smoke test value.After the judgment, the test result is displayed on the indicator.

After the detection is completed, when the indicator prompts "forward", the car can be driven to the next station.

(4) Station P This station manually checks the condition of the vehicle bottom.Inspectors check in the trench whether the connection of components is firm, whether there is deformation, breakage, water, electricity, oil, gas leakage, etc., and transmit the test results to the main control computer through walkie-talkie or special keyboard and other equipment.When the main control computer judges the result, as long as there is one unqualified item, it is judged that the vehicle bottom inspection is unqualified.And the judgment result is displayed through the station inspection program prompter.

After all the tests are completed, the main control computer makes a comprehensive judgment based on the previous test results.Only when all inspections are qualified, the overall judgment of the vehicle inspection is qualified, and as long as one item is unqualified, the overall judgment is unqualified.Then print out the test list after storing the data.After the driver gets the test result report, he immediately drives the car out of the test line, and the whole line test is over.

Cars that fail the test must be sent to a repair shop for repairs, and then re-inspected.

[-]. Control system of automobile inspection line

Modern automobile inspection lines have generally adopted computer control systems.On the fully automatic vehicle inspection line, the computer control system can automatically complete the inspection tasks of the corresponding inspection items of the inspection line and save the inspection results by controlling each inspection equipment.

1. Composition of computer control system
In the automatic inspection line of automobiles, the computer control system consists of two parts: hardware and software.

(1) Control system hardware
The hardware of the computer control system is composed of inspection machine, main control machine, interface control box, stand-alone instrument and auxiliary equipment.

(2) Control system software
In addition to the testing program, the software part of the control system generally includes database management, equipment calibration program, testing standard correction program, system self-test and self-diagnosis maintenance program, etc.Among them, data management can archive the data of all vehicles that have been detected, and can retrieve, browse and process according to certain conditions.

2. The control method of the computer control system
Generally speaking, the computer control system mainly has two kinds of control methods: distributed and centralized.

(1) Centralized control system

The centralized control system uses a single host to directly monitor the entire site, and the structural control system without a workstation is shown in Figure 5-5. It uses software to perform logical division of workstations and time-sharing processing to complete the automatic control of the controlled equipment. Detection control.

(End of this chapter)