Diesel vehicles free acceleration smoke detection

Diesel vehicle exhaust smoke detection, preclude the use of no-load free acceleration.

(1) the preparation of the smoke meter.

The smoke meter is turned on after the warm-up period of time (filter type smoke meter for 5min as described above, not through the photometer for more than 15min). When necessary, should carry out a calibration check. For the filter smokemeters available smoke card, available for the opacity of the smoke meter linearity check and filter check.

1) Automatic linearity check. The instrument automatically generate a 509 ^ to meet the range check signal ‘and automatically check the corresponding output to meet the requirements.

2) The filter checks. Will filter into the instrument detection unit checks jack, the instrument displays the corresponding readings, the error is greater than ± 2% opacity.
(2) the preparation of the car.

Pre-test, the diesel engine in the idling condition.

(3) smoke detection.

Exhaust smoke should be the relevant provisions of GB3847 – 2005 test, the sub-filter smoke and opaque smoke two kinds of test methods. Diesel vehicles free acceleration smoke test procedures are as follows:
1) Install the sampling probe. Insert the sampling probe into the exhaust pipe, depth of not less than 300mm, and its center line and the exhaust pipe parallel to the axis.
2) blow the accumulated material. Starting the engine, acceleration three times, the free acceleration smoke test specification shown in Figure 4-17, to blow the carbon residue accumulated net exhaust pipe.
3) measurement of sampling. For the filter smokemeters, sampling of the smoke meter should be foot pedal switch to the accelerator pedal, gas pedal quickly step on the end, sustained 4s, and then release the accelerator pedal 11s. For opaque smokemeters, must be within 1s to the accelerator pedal fully adopted in the end, so that the injection pump to supply the maximum amount of oil in the shortest time. Each free acceleration measurement, release the accelerator pedal, the engine must reach the speed of the fuel cut-off point.

The filter smokemeters loop measurement four times, the calculation results to take the arithmetic mean of three readings measured free and opacity smoke meters, measuring at least six times, the calculation results to take the last three free acceleration measurements the arithmetic mean. Can be ignored in the calculation of the mean difference between the measurement value and measurement mean.

Opacity smoke meter testing smoke

 The opaque smokemeters smoke instruments to measure light in the exhaust flue gas abatement extent. Opacity smoke meter is divided into the full flow and diversion categories. Full-flow opacity smoke meter to detect the smoke through the measurement of all the exhaust transmittance attenuation rate Split opacity smoke meter is to detect smoke transmittance decay rate by measuring the part of the flue gas. (1) detection principle. Not the transmittance smokemeters mainly by the composition of the light source, optical channel and optical receiver, the basic detection principle shown in Figure 4-14. Opacity smoke meters light visible light emitted by the light of a certain effective length, filled with the measured flue gas channel, the light intensity is flue gas absorption, while the amount of light attenuation through the flue gas reaches the optical absorption, so the optical absorption The output light intensity attenuation is proportional to the opacity signal, so as to detect smoke. Exhaust the absorption of light (or attenuation) and the ability to reflect the size of the exhaust smoke, the available optical absorption coefficient (K) said. The optical absorption coefficient (K) the attenuation coefficient of the length of the beam to be as early bit of smoke, which is the unit volume of the particle number n, the extinction coefficient of the average projected area of ??the particles A and particles Q multiplied by the three in the measurement of smoke , most of the operating conditions of the diesel soot particles A and Q values ??changed little, while the density of each particle is roughly equal, therefore, can be approximated that the quality is directly proportional to the concentration of the optical absorption coefficient of soot. According to GB3847-2005, the light absorption coefficient as evaluation of the smoke emissions from diesel vehicles, so the opacity of the smoke meter optical absorption coefficient should be used as the unit of measurement, it is an absolute units of light absorption. But some opacity of the smoke meter with opacity as a unit of measurement, opacity means the light was absorbed by smoke and can not reach the percentage of the optical receiver. (2) full-flow opacity of the structural principle of the smoke meter. The full-flow opacity the smokemeter structure principle shown in Figure 4-15. It is based on the photoelectric conversion principle, the light transmission to the determination of exhaust gas concentration. Side not far from the exhaust in the exhaust pipe smoke beam are arranged on both sides of the light source and photocell, smoke, light battery to accept the opacity degree of signal proportional to the exhaust smoke. In order to reduce the thermal effects of exhaust, the light source and photoelectric components on a certain distance away from the exhaust channel. (3) Split opacity of the structural principle of the smoke meter. Split opacity smoke meter uses light to measure the decay rate through the opaque part of the flue gas exhaust smoke, and its structural principle is shown in Figure 4-16. Blower to the air calibration tube before the test blown clean air ‘rotating change-over lever, so that the light source and photocell calibration tubes were placed on both sides, for the zero point correction. Then, and then rotate the conversion handle, move the light source and a photocell to test tubes on both sides and part of the exhaust to be measured continuously import test tubes, light sources part of the exhaust flue gas attenuation, the photoelectric detection unit continuous measurement of the intensity of light emission of light transmittance through the row, gas, and photoelectric conversion shows the measurement results. Smoke indicated value of 0 indicates that smoke-free, 100 black. Opacity smoke meter for continuous measurement of diesel exhaust emission regulations according to the requirements of smoke measurement of the steady-state and non-steady state conditions, low smoke have a higher resolution, the current , has been widely used in countries around the world.

Circuit test method

 Circuit detection method is the use of automotive multimeter or oscilloscope test equipment such as circuit, the components of the system and line of resistance, voltage, current, digital signals for dynamic and static testing, test results and then according to the standard and comparison service manual to determine failures.

1.4.3   Special instruments test

 General use of special equipment, there are two, namely, the configuration of the decoder and factory testing of a system with the monitor.Original decoder can be divided into two types of special-and general-purpose.Original purpose-decoder, such as: Volkswagen VAG1551 and VAG1552; Ford STAR2; Chrysler DRB2 and so on.  U.S. real Snap (Snap-On) produced Scanner; Ouwa Dayton Le tools produced OTC decoder; OBD2 self-diagnostic OBD2 system supporting various types of decoders.Domestic decoder has electric eyes，instrument king，Repair auto King and so on.

Automatic transmission electronic control system malfunction diagnostic tests

1.4.1  Array of the original car it self-diagnostic system for diagnosis method

 Electronic control unit (ECU) is an important role in the signal received at any time a comparative analysis, if the abnormal situation is a warning signal, and abnormal (fault) in the form of content to code stored by fault diagnosis system extract fault codes to guide maintenance work.

 Self-diagnostic fault information system there are two access methods, namely artificial reading and reading instrumentation (the decoder). Reading is the use of artificial fault diagnosis way across the connector terminals and terminals shorted to self-diagnosis, through the fault light flashing frequency to determine the fault. Manual reading convenience, no special equipment, but requires technical personnel familiar with the various models and different methods of reading the code content. Decoder reading just need to know the interface and the instrument detection and diagnosis methods of operation, you can easily read the fault directly to the content, but the car must be equipped with adaptive decoder.

Dragging the rear brake failure

Models: Santana 20000Gli type, produced in 1998.

Symptom: right rear wheel bearing damage fast, two replacement mileage interval less than 200km.

Diagnosis and exclusion: the right rear wheel, the outer bearing in such a short time continuous damage, the bearing may be due to poor quality, poor lubrication, assembly gap is too small. Outside in the last replacement bearings, inner and outer bearings are short sleeves, they were filling up to two lithium based bearing grease. The bearings are original replacement parts. Second replacement bearings, two bearing grease on to become very thin, and most have been out, indicating the bearing overheated. Analysis of the wheel bearing overheated reasons:
(1) wheel bearing assembly too tight;
(2) outside the shaft bearing seal or cover damage caused by grease thrown from the defects, due to lack of lubrication of the bearing and overheating;
(3) The vehicle is in motion, there is a serious brake drag wiring, brake drum and brake shoe heat, melt the grease out of bearings due to lack of lubrication and overheating;
(4) filling of the oil is not oil resistant Gao Wen.

Asked that maintenance personnel, the last adjustment of the right wheel bearing clearance, and also confirmed after dismantling the proper clearance, the bearing is not tight. And then check the wheel oil seal, oil seal is aging. However, according to Seal the current situation, not only in vehicle running in 2001 ^ 01 bearing on the burn. Check the vehicle outside the shaft well cover, brake drag the rest of the reason is stagnated. Dragging a single wheel brake reasons:
(1) poor brake lines or brake sub-Li card;
(2) The brake gap is too small;
(3) The brake shoe return spring is too soft, break or fail;
(4) The parking brake system block phenomenon.

Check the patency of the right rear brake lines, brake wheel cylinder flexible movement; Santana rear brake with automatic adjustment of the gap function, check the gap is also appropriate; normal brake shoe return springs; continuous pull the parking brake several times , we found that sometimes the right rear wheel parking brake does not return bit by checking the parking brake cable is damaged.

Replacement parking brake cable, put in new bearings and seals, and put on the brake drum, the outer bearing clean, coated with an appropriate amount of lithium grease, and then fitted; then fitted thrust washer, screw Thrust hexagonal bond mother, the bearing pressed, then turn the hex nut counter-clockwise, and check the wheel bearing clearance. Santana models bearing clearance requirements are: using a screwdriver under pressure in the fingers, just to toggle thrust washers. The correct adjustment, the vehicles run properly.

Analysis: Due to bearing overheating, melting the lubricant out of the phenomenon, in practice also called “dump oil”, is a common symptom on the wheel.

This case failure, reflecting the kind of thinking, that if a system failure or institution, except in the system or organization looking for reasons, but also deal with the system or institution closely associated with the analysis of systems or institutions, to find fault the reason why. If the engine temperature is too high, because in addition to cooling, the ignition timing are not allowed, burning of poor quality, lack of lubricating oil and other reasons, but also make the engine temperature is too Gao.

 Typical failure of braking system 

 
6.4.1  Brake not working Fault

 Models: the hatchback Fukang cars, produced in 1996, the cumulative mileage 250000km.

 Symptom: When deceleration is very soft, emergency braking, the braking distance was too long.

 Diagnosis and exclusion: to prevent the phenomenon known is the brake not working. This failure caused by many reasons, such as the pedal free travel is too large, lack of brake fluid, hydraulic brake cylinder cup seal the total poor, poor brake pipe system with air, improper adjustment of the wheel brakes.

 Test the car’s braking performance, four had no locking phenomenon, the initial failure to determine the brake master cylinder and brake pipe in the road. Through the brake pedal test, free travel normal, depresses the brake pedal did not play sexy, and you can step on the brake pedal hard, do not sink, failure is not caused by air resistance, nor is it the brake master cylinder or pipe leak caused of. So is what causes it? Asked the driver that the car has been in other repair shop repair, brake system, the main assembly parts are replaced (brake master cylinder, wheel cylinders>, but the fault still exists.

 Check whether there is air in the brake pipe was found, at each wheel cylinder exhaust bolts Although there is no bubble, but the discharge of oil pressure is low. Further check the brake lines, not found flattened, bent at. Low oil pressure at the wheel cylinder brake lines cause is poor.

 The brake fluid within the braking system exclude clean, would go to the oil and strong cleaning agent added to the tank, the repeatedly depresses the brake pedal, brake wheel cylinder from the exhaust bolts at the exclusion cleaner. Rule out the color deep and turbid liquid, that the accumulation of dirt, the brake pipe quite thick, making the actual flow of brake fluid narrow diameter, the resistance increase. When cleaning the system once again, excluded from the wheel cylinder fluid pressure at significantly increased. After filling the new brake fluid. The exclusion of the air system, the brake fluid pressure is high, were sprayed. After a road test, good braking performance, troubleshooting.

 Analysis: This type of failure, the mileage or long life of the vehicle hydraulic brake widespread.

Chassis Troubleshooting

 Learning objectives

 Knowledge of the target
 1 can be briefly described automobile chassis common symptoms and causes, the correct description of the chassis common fault characteristics;
 2 master chassis common fault analysis to determine the ideas and methods, and can sum up the essence of failure.

 Ability to target
 1  under the guidance of teachers, the failure to analyze the phenomenon of the chassis, the right to determine where the fault;
 2  able to complete the fault diagnosis of common chassis, and can eliminate common problems.

 Chassis technology pros and cons of the situation related to vehicle handling and stability when driving and safety, but also affects the transmission of engine power and fuel consumption. Therefore, timely and accurately determine the portion of the chassis and remove the fault is very important. The unit will be from the transmission system, driving system, steering system and braking system and other parts, introducing the chassis phenomenon common fault, cause analysis and diagnostic troubleshooting.

Car diagnostic Training courses

(1) under the guidance of teachers, setting the engine electronic control common failure to understand the failure characteristics, learning to use automotive diagnostic failure.
(2) set in the common electronic control engine failure, use the correct method to determine and troubleshooting.

Thinking and practice
First, fill in the blank
(1) There are two forms of fault code ____ and ____ There have been over but now there is no fault called ____.
(2) electronic control unit is faulty cause ____,____。
(3) throttle position sensor failure will lead to ____,____,____,____。
(4) oxygen sensor failure can cause ____,____,____,____。
(5) Knock sensor failures can cause ____,____。
(6), the fuel pressure is too low will lead to ____,____,____,____ symptoms.

Second, the choice
(1) air flow sensor failure may lead to ____ failure.
A. No B. Engine will not start high voltage ignition engine idle speed instability C.
(2). PCV valve failure will result in ____ failure.
A. B. engine idling engine overheating engine emissions exceeded adverse C.
(3) failure indicator light indicates that the vehicle ____
Electronic control system malfunction A. B. C. faulty instrument has mechanical failure
(4). VAG1551 is ____ decoder.
A. General B. VW car Private European cars C.
(5) damage to the crankshaft position sensor, engine ____
A. can not B. dysfunctional C. the car difficult to start
(6) when excluding electronic control system failure, fault codes ____
A. disappear B. C. can not be disappeared to clear the fault code to be processed before it disappears

Third, determine the question (the right picture V, the wrong picture X>
(1) throttle position sensor malfunction can cause the engine not starting. ()
(2) ignition signal generator damage to the engine will not start. ()
(3) appropriate to reduce the fuel pressure regulator adjustable hydraulic can reduce fuel consumption. ()
(4) hair only in the cold start injector when starting work. ()
(5) premature ignition timing is an important reason leading to deflagration. ()
(6) that the engine fault light does not shine without failure. ()
(7) replacement of defective devices from the engine, the fault code will be automatically removed. ()
(8) fiscal code 05 electronic control system failure may reflect the failure of a cylinder injector. ()
(9) repair throttle position sensor, the need to use the decoder to reset the throttle position. ()
(10) hot-film air flow meter output voltage increases with the amount of air. ()

Fourth, Questions and Answers
(1) how to clear engine fault codes?
(2) intake air temperature sensor failure which may lead to symptoms?
(3) how to distinguish where the system failed?
(4) signs of the engine without the car, how to determine the fault position?
(5) Try to analyze the possible causes unstable idle.
(6) Try to analyze the possible reasons for lack of engine power.

 use special instruments to obtain Failure code

 ① Select the detection and diagnosis of models supporting seat, in the ignition switch turned off and the engine cradle is connected to the diagnosis.
 ② Open the fault diagnostic, select the test models, input the necessary data.
 ③ Turn the ignition switch, read the fault code, fault code according to the initial prompt to determine the fault position.
 ④ actuator detection of suspected faulty components in depth inspection to determine the faulty components.
 ⑤ replace the faulty device, clear fault codes, re-starting the engine, check whether there fault code, fault symptoms are gone.
 Read fault code, fault code table can be read against the meaning of failure, the fault location may be further confirmed.

 2.1.2   Using common methods to read, clear the fault code

 Some models can be shorted fault diagnosis socket, according to the fault warning lights flashing message read fault codes, such as the red car, Tianjin Wei Chi has such a detection.
 Turn the ignition switch “ON ‘, does not start the engine. With a short troubleshooting spare fuse socket (blue) shown in Figure 3-20, this time, the warning light goes out immediately. After 3.2s, if the system is no fault is no fault code flashing light cycle code “12″; if the system failure, malfunction indicator light flashes according to the sequence of failure fault code, fault codes for each successive flash three times. Note: to read fault codes , fault diagnosis socket short time do not exceed 7min, otherwise it will remove all the code. warning light flashing fault code consists of ten and a bit double-digit form, each number is the number of flashing warning lights to represent the number of times, 0 flashes 10 times, 1 flash 1, 2 flashes 2 times, and so on. lights flashing interval of 0.4s, and bit and bit flash gap between the 1.2s, the groups the interval between the flashes 3.2 s.
 Clear the fault code after repair when the ignition switch “ON”, do not start the engine, with a spare fuse socket 7min short troubleshooting over the fault code will be automatically eliminated, warning light flashes trouble codes code “12″ . Unplug the spare fuse, clear fault code completion.

 2.2    Part of the vehicle engine control system failure code

2.2.1  Santana 2000GLi common engine control system malfunction code
 Table 3-5 shows equipment 200000 Santana AFE: engine electronic fuel injection system common trouble codes.

2.2.2  Red car engine control system failure code table
 Red car equipment CA488 series and CA4GE series engines produced by Siemens AG of Germany (SIMOS) electronic control system, the fault code can be an ordinary method call, can also be used VAG1551 automotive fault diagnostic testing, the meaning of the failure code is shown in Table 34.

Electronically controlled engine fault diagnosis system applications

The electronically controlled engines are equipped with self-diagnostic function, when the system fails, the code will fail category to keep people in the form of memory failure for maintenance personnel to find fault with, but the failure warning light on the dashboard lights to alert the driver system failure, timely maintenance. Faults stored in two forms: one is intermittent fault that the system there have been but now there is no failure, it does not affect the current work the engine, such failures have caused by vibration or bad, when the engine starts more than certain number of times, if no failures occur, many models of the electronic control system will automatically eliminate such fault code; the other is a permanent fault, it is the failure of the engine there is now a direct impact on engine performance, the fault code has been stored in the fault memory, the need to rule out the failure to remove and clear the code, then the electronic control system will enable the backup program (also known as claudication function), take appropriate protective measures (limited engine speed) to maintain engine , making the vehicle can go home or go to the repair shop for maintenance. Backup program system, also known as home systems.

2.1 Fault code display and clearance method Fault code of display and cleared method has two kinds: (1)Use special decoder or universal decoder,For example the public series special equipment is VGA1551 fault diagnostic instrument or VGA1552 car system diagnostic instrument,General decoder by the United States as the red box MT2500 decoder,Germany BOSCH company produces the KTS300/500 decoder,The production of OTC series decoder and domestic production electric eyes (432 ME) the car like dr king instrument, etc。 (2)Some of the vehicles available to ordinary method, short sub fault diagnosis summoned a fault code。