Car Maintenance Basics

Chapter 13 Project Five Automobile Testing Equipment (3)
5. Tool finishing and site cleaning
[-]. Teacher Evaluation

Evaluation status of serial number evaluation items
Good to bad

1 Attendance
2 dressing situation

3 classroom order
4 Whether learning is proactive
5. Fill out the learning task book

6 Use of tools and instruments
7. Tool finishing and site cleaning
Four vehicle performance testing equipment

Learn
Knowledge goal:

Learn about the types of automotive performance testing equipment.

Master the basic knowledge of automotive performance testing equipment.

Skill Goal:
Able to operate commonly used automotive performance testing equipment.

Master the skills of using automobile performance testing equipment to carry out automobile maintenance.

task description
Under the guidance of relevant knowledge, understand the basic knowledge and technical requirements of commonly used equipment for automotive performance testing.Under the guidance of work order tasks, can operate vehicle performance testing equipment for vehicle testing.By learning and mastering the operation skills of automobile performance testing equipment, record and archive the completed work, and consciously maintain safe operation and 5S work requirements.

related information
[-]. Power performance testing equipment

1. Automobile chassis dynamometer

The automobile chassis dynamometer is shown in Figure 5-18.It is used as follows:

① Before starting the machine, prepare the chassis dynamometer according to the requirements of the instruction manual.

② Operate according to the prescribed procedures.

③The inertial simulation system is not allowed to be used arbitrarily except for multi-condition fuel consumption test, acceleration and coasting test.

④ In the event of a sudden power failure, the driver should release the accelerator immediately and put it in neutral.

⑤The driver must strictly follow the prompts of the guidance system to operate.

2. Wulunyi

The five-wheel instrument is shown in Figure 5-19.Its usage is as follows:

(1) Installation of the five-wheel instrument
①Fixly install the five-wheel instrument at the rear of the test vehicle so that the center of the mounting plate is about 600mm from the ground.

②Use the sensor clip to securely install the sensor on the connecting arm facing the ring gear at a distance of 1mm from the top of the tooth.

③Inflate the Wulunyi tires properly.

④ Connect the wires.During the braking test, fix the foot switch on the brake pedal; during the continuous shift test, fix the foot switch on the clutch pedal.

(5) Sensor coefficient calibration and setting
Whether the sensor coefficient is accurate or not will directly affect the accuracy of the test results.Before the test, the sensor coefficient must be calibrated.The calibration of the sensor coefficient is carried out under the premise that the five-wheel instrument is installed and the sensor is in good working condition.

① Check the working status of the sensor.Turn on the power switch, after the display [Reset], press the [Calibration] key twice, and then press the [E] key, the five-wheel instrument enters the calibration state.At this time, slowly rotate the five wheels for 1 week, and the display shows [172] (rotating w circles should show 172-n).

Then [Reset] on the display, press the [Speed] key, and then press the [Execute] key to enter the speed working condition.After turning the pentameter at a slow speed, the red light of the LED on the display will flicker, and the display of the speed value will also be stable.

If the above two conditions are met at the same time, it means that the sensor is in good working condition; otherwise, after checking the installation of the sensor and the connection of the wires, check the working condition of the sensor again.

② Sensor coefficient calibration.

a. Accurately measure 100m or 50m in the test road section as the calibration distance, and erect benchmarks at both ends.

b. After the display [Reset], press the [Calibration] key twice, and the display will display [dl00] at this time, indicating that the calibration distance is 100m; if the calibration distance is 50m, you can directly press the number key [5][], When the display shows [d50], it means the calibration distance is 50m.

c. The test vehicle runs at a low speed (less than 20km/h). When the vehicle reaches the starting point, press the [E] key to enter the calibration condition; when the vehicle reaches the end point, press the [D] key to end Calibration working conditions, the display automatically prints the calibration results, and the sensor coefficients are automatically stored.

For example, the print result is: d=09969, which means the sensor coefficient is 09969cm/pulse.

d. In order to make the sensor coefficient calibration accurate, it is recommended to perform two calibrations, take the average value of the two calibration results as the sensor coefficient of this test, and set the sensor coefficient in the display.

③Sensor coefficient setting.

After the display is reset, press the [Calibration] key, and then press the [kd] key, the display will display [7], at this time press the new sensor coefficient key to complete the coefficient setting work.

For example: kd=09969, then key [09969] and display [09969].

Another example: kd=10260, then key [010260] and display [010260].

If you make a mistake in keying, you can press the [kd] key again to key in a new value.

After the coefficient setting is completed, the test can be carried out.Note that the machine cannot be turned off during the test, otherwise the sensor coefficient should be reset.

(3) Test operating procedures
①Initial stage.Turn on the machine or press the reset button, play the opening song, and display the word "Good".

② Select working conditions.According to the content to be tested, press the corresponding function key, and the instrument will automatically enter the control program of the working condition.

③Preset data.According to the test procedure, first set the relevant parameters (such as: initial speed, final speed, sampling speed interval, etc.).Before setting and inputting the above parameters, press the corresponding letter key before the relevant parameters, add B before the initial velocity value, add A before the final velocity, and add C before the sampling interval, (if the final velocity of the acceleration test is 70, then A70 should be pressed.)
④ preparation stage.After checking that the test conditions are fully met, press the [Execute] key.

⑤ Test process.The test vehicle starts to run, and when the driving speed reaches the initial speed requirement of the test, press the [Execute] button again, and the instrument enters the test sampling stage.

⑥ The test is over.After the test sampling is finished, the instrument prints the test results by itself.

⑦ Reverse test.If you want to repeat the test in reverse, you can press the [Execute] key twice in succession. When the vehicle speed reaches the initial speed of the test, press the [Execute] key again. After the test sampling is completed, the instrument will print out the test results.If you need to output the average of the positive and negative two test results, you can press the [Execute] key again, and the instrument will print out the average value.

For the use of the instrument in the specific test, the instruction manual should be read in detail.

[-]. Economic performance testing equipment

, the car will be printed out when driving at a certain speed.

[-]. Brake performance testing equipment

The multi-function fuel consumption meter is shown in Figure 5-20.In the road test to detect fuel consumption, the fuel consumption sensor is generally used in conjunction with a non-contact or contact five-wheel meter.When all conditions meet GB/T12545-1990, start the road test.Taking the non-contact five-wheel instrument as an example, first set the measurement distance (500m) and the measurement gear on the non-contact five-wheel instrument, and then start detection. When the vehicle speed stabilizes to a certain measurement speed (for example, 50km/h), Press [START] on the speedometer.Until the car travels 500m mileage (the speedometer automatically stops measuring at 500m because the distance of 500m is set), then press the [Stop] button.The fuel consumption of the 500m mileage and the converted fuel consumption per 5 kilometers are shown in Figure 21-[-] on the vertical drum brake test bench.Its usage is as follows:

① The tire pressure of the inspected vehicle should meet the specified value, and the tire surface should be clean.If there are oil stains, water stains or small stones embedded in the tire pattern, they must be removed and wiped; otherwise, the adhesion coefficient between the tire and the roller will be reduced, and the detection accuracy will be affected.

② Turn on the main power supply of the brake test bench.

③Start the lifter between the rollers.

④ Drive the inspected vehicle between the two rollers.

⑤ Lower the lifter between the rollers and ensure that the lifter supports
The plate is completely disengaged from the wheel.

⑥ Turn on the power supply of the drive roller motor of the test bench to make the roller rotate.

⑦Depress the brake pedal and read the maximum braking force value indicated on the meter.

⑧ The front and rear axle wheels are detected in sequence, and after the detection is completed, the power supply of the drive motor is cut off.

⑨The lifter is raised, and the car drives out of the test stand.

⑩After the test is completed, cut off the main power supply of the test bench.

[-]. Headlight performance testing equipment

The car headlight tester is shown in Figure 5-22.Its usage is as follows:

① Slowly drive the inspected vehicle to the headlight tester, ensure that the longitudinal axis of the vehicle is perpendicular to the light guide rail of the headlight tester, and keep the standard distance between the headlights and the tester (determined according to the model of the tester).

②The engine is idling and the battery is charging.

③Use the aligner on the headlight tester to align the tester with the headlight of the vehicle to be tested.

④ If the car is made of four lights, cover the headlights that are not tested temporarily, and only keep one headlight.

⑤ Turn on the headlights, and measure the axis deflection and luminous intensity of the headlights respectively.

⑥ According to the above steps, inspect each headlamp one by one.

⑦ After the test is completed, the headlight tester is removed, the car drives away from the test station, and the power supply of the tester is cut off.

[-]. Speedometer test bench

The car speedometer test bench is shown in Figure 5-23.In actual use, due to the different forms and grades of the speedometer test bench, its use method is also different.Before use, be sure to read the "Instruction Manual" of the test bench carefully, and use it correctly according to the provisions of the "Instruction Manual".The general usage is as follows:

1. Preparation before testing
(1) Test bench preparation Figure 5-23 Automobile speedometer test bench

① When the drum is in a static state, check the zero position of the indicating instrument, and adjust it if there is any deviation.

② Check whether the drum is stained with oil, water, mud and other sundries, and remove them if any.

③ Check whether the lifter moves freely and whether there is any air (or oil) leakage, otherwise, repair it.

④ Check the connection of the wires, if there is a bad contact or an open circuit, it should be repaired.

Checked vehicle preparation
①Adjust the tire pressure according to the regulations of the manufacturer.

②Remove the water, oil, mud and stones embedded in the tire tread grooves on the tires.

2. Detection method

① Turn on the power of the test bench.

② Raise the lifter between the rollers.

③The vehicle under test drives into the test bench from the direction where its longitudinal centerline is perpendicular to the axis of the roller, so that the wheels with vehicle speed signals are placed on the roller.

④ Lower the lifter until the tires are completely separated from the lifter support plate.

⑤ For the sake of safety, no one should stand in front of the vehicle, and block the wheels outside the test bench roller.

⑥For standard speedometer test bench:
a. Start the car.After the driving wheel of the car is stable on the roller, put it in the highest gear, step on the accelerator pedal, and make the driving wheel accelerate smoothly.

b. When the indicated value of the speedometer of the vehicle reaches the specified detection speed (0km/h), read the indicated value of the speedometer of the test bench; or when the indicated value of the speedometer of the test bench reaches the detection speed, read the indication of the speedometer of the vehicle value.

⑦ For motor-driven speedometer test bench:
a. Engage the test bench clutch to connect the drum shaft to the motor pivot.

b. The transmission of the car is in neutral, and the power supply of the test bench is connected to make the motor drive the drum to rotate.

c. When the speedometer of the vehicle reaches the detection speed, read the indication value of the speedometer of the test bench; or when the indication value of the speedometer of the test bench reaches the detection speed, read the indication value of the speedometer of the vehicle.

⑧ After the test is over, lightly step on the brake pedal of the car to stop the rotation of the drum.Note that for the motor-driven test bench, the power supply must be cut off first.

⑨Raise the lifter to remove the block, and the car drives away from the test stand.

⑩ Cut off the power supply of the test bench.

[-]. Gasoline vehicle emission pollutant testing equipment

The automobile exhaust gas analyzer is shown in Figure 5-24.Its usage is as follows:

1. Preparation of the Instrument

① Turn on the power and preheat the analyzer for more than 0.5h.

② Calibrate with standard gas sample.

③Simple calibration, turn on the simple calibration switch.For analyzers with scale lines for calibration positions, use the standard adjustment knob to adjust the pointer of the indicator to face the scale lines for calibration.If there is no scale line for the calibration position, mark the standard indication value when calibrating the standard gas sample, and then perform a simple calibration immediately, so that the needle of the instrument indicator 524 coincides with the mark of the standard indication value.

④Install the sampling head and sampling conduit on the analyzer, and note that if the pointer of the instrument exceeds zero, it indicates that there is more HC adsorbed on the inner wall of the conduit, and it is necessary to clean the sampling probe and conduit with compressed air or cloth strips.

2. Prepare the vehicle to be inspected
①Start and preheat the engine to make it reach the specified thermal state.

②Adjust the idle speed and ignition timing according to the regulations in the instruction manual of the vehicle.

③ The exhaust system of the inspected vehicle must not leak.

④Insert the sampling probe of the analyzer into the exhaust pipe (muffler). Different sampling probes should be used for engines with different stroke numbers, and the depth of insertion into the exhaust pipe should not be less than 400mm; Airtight.

3. Detection steps

① Accelerate the engine from idle speed to medium speed, maintain it for more than 5s, and then reduce to idle speed.

②Turn the reading conversion switch of the indicating instrument of the analyzer to the highest range gear.

③Insert the sampling head into the exhaust pipe at a distance of 400mm.

④ Select an appropriate range, and read after the pointer stabilizes.

⑤ If there are multiple exhaust pipes, take the arithmetic mean of the values ​​of each pipe.

⑥ After testing, take out the sampling probe, let it inhale fresh air for 5 minutes, and then turn off the power after the pointer of the meter returns to zero.

[-]. Diesel vehicle emission pollutant testing equipment

The smoke meter is shown in Figure 5-25.Its usage method is:
1. Instrument Preparation
① Instrument calibration.

② Check the working conditions of the various parts in the sampling device and the control device, especially check whether the foot switch and the piston pump are in sync.

③ Check whether the pressure of compressed air for control and compressed air for cleaning meets the requirements.

④ Check whether the filter paper feeding mechanism works normally.

⑤ Check whether the filter paper is qualified, it should be clean and free from dirt.

2. Vehicle preparation
①The air intake system should be equipped with an air filter, and the exhaust system should be equipped with a muffler.

② Diesel oil should comply with the provisions of GB10327, and fuel additives are not allowed.

③ When measuring, the temperature of the cooling water and lubricating oil of the engine should reach the thermal state specified in the instruction manual of the vehicle.

④ Since July 1995, 7, for diesel engines used in newly produced diesel vehicles, it should be ensured that the start-up enrichment device will no longer work under non-start conditions.

3. Measurement procedure
①Clean the sampling pipeline with compressed air at a pressure of 0.3-0.4MPa.

②Place the piston pump at the position to be pumped, put the clean white filter paper at the position to be sampled, and clamp it tightly.

③Fix the sampling probe in the exhaust pipe, the insertion depth is equal to 300mm, and make its axis parallel to the axis of the exhaust pipe.

④Introduce the foot switch into the cab of the car, but do not fix it on the accelerator pedal for the time being.

⑤ Write down the test serial number, test conditions and test date on the blackened filter paper for preservation.

⑥ When the test is over, turn off the power and air source in time.

task implementation
According to the guidance of the work order, complete the operation of the common equipment used in automobile maintenance. In the process of task implementation, learn the operating procedures and maintenance methods of automobile maintenance equipment, and implement in groups to complete the work within the specified time.

[-]. Tool preparation

Tip: Before implementing the homework, each group should prepare the materials and tools needed for this learning task according to the table below.

Data, number of names of tools Data, number of names of tools
One set of commonly used tools for the whole vehicle

One jack, one light detection equipment

One exhaust gas analyzer One two-column lift

A set of car testing equipment

[-]. Technical standards and requirements
① All operations meet the requirements for safe operation.

② All operations are in compliance with the operating procedures of automobile performance testing equipment.

③ Safety accidents are not allowed during the operation.

[-]. The work to be done

1. Check the brake performance of the car with the brake tester. The operation steps refer to the relevant knowledge content, and fill in the following table for the test record.

2. Use of exhaust gas analyzer
Refer to the equipment instruction manual for the operation steps, and record the inspection results.

3. The use of light detection equipment
Refer to the relevant knowledge content for the operation steps, and record the inspection results.

[-]. Training report

How to use and operate steps of automobile brake test bench, automobile light inspection instrument, automobile exhaust gas analyzer and other equipment.

learning assessment
[-]. Self-evaluation

1. Summarize the main types of vehicle testing equipment.

2. Please write down your experience of this learning task.

3. Self-evaluation of the learning environment (including dress, learning attitude, mastery of knowledge and skills, completion of work pages, etc.).

[-]. Group evaluation

Evaluation status of serial number evaluation items
Good to bad

1 team spirit
2 Whether learning is proactive
3 The situation of obeying the work arrangement

4 Use of tools and instruments
5. Tool finishing and site cleaning
[-]. Teacher Evaluation

Evaluation status of serial number evaluation items
Good to bad

1 Attendance
2 dressing situation

3 classroom order
4 Whether learning is proactive
5. Fill out the learning task book

6 Use of tools and instruments
7. Tool finishing and site cleaning
thinking and practice
1. Precautions for using the car multimeter?
2. Measure the sensor waveform with a car oscilloscope and analyze it-
3. What are the functions of the fault decoder?
4. Briefly describe the operation steps of four-wheel alignment.

5. Briefly describe the steps of headlamp performance testing.

(End of this chapter)