Maintenance example

& gt& gt

54

The Great Wall Haval supercharged * * rail engine emits black smoke.

Black smoke; Suddenly accelerated, black smoke billowed.

Before describing fault diagnosis, it is necessary to

GW2.8TC supercharged * * rail diesel engine is simple.

Introduction. This engine is made by Baoding Great Wall internal combustion engine.

The company launched in August 2006, which is the first model in China.

Supercharged * * rail engine with independent intellectual property rights adopts

The power supply is provided by CRS2.0 high voltage * * * rail of BOSCH company.

Oil system. The maximum oil supply pressure of the system is

145MPa, and the oil supply process is controlled by Bosch EDC 16C39.

E electronic control unit for control.

Main control of engine electronic control system

It consists of various sensors, ECU,

Actuator and connecting wire harness, etc.

All right. Its sensor has water temperature transmission.

Sensor (negative temperature coefficient, 2)

Terminal), engine speed

Sensor (electromagnetic induction type, with

3 terminals), camshaft

Phase sensor (Hall effect

Type, 3 terminals), acceleration

Pedal position sensor (dual)

Horizontal type, 6 terminals),

Air flow sensor (hot film

Type, 4 terminals) and * * *

● Text/Heilongjiang Liu Hua

Fault phenomenon

A 2007 rear-wheel drive Great Wall Haval

CUV car, with a mileage of 2300km, equipped with GW2.8TC

T-type turbocharged diesel engine and 5-speed manual gearbox.

According to users, the engine of the car is emitting black smoke.

fault diagnosis

After repairing the car, start the engine and start it smoothly.

Move it. The engine idles smoothly and accelerates strongly, but idles.

The flue gas discharged during operation is grayish white; Uniform acceleration, exhaust pipe

Rail pressure sensor (pressure sensitive element type, 3 terminals)

Son). The actuator controlled by ECU is fuel injector (2 connections).

Line terminal), high pressure oil pump feed metering proportional solenoid valve (2

Terminal), such as the right solenoid valve (2 terminals

Sub), glow plug, air conditioner and electric fan.

The fuel supply system of the engine consists of low-pressure oil circuit and

Composition of high pressure oil circuit. The low-pressure oil circuit comprises an oil tank, an oil pipeline,

Fuel filter (with oil-water separator and hand oil pump), transmission

Oil pump (gear type, located in high-pressure oil pump) and high pressure

Low pressure area of oil pump; The high pressure oil circuit is high pressure.

High pressure area of oil pump, * * * rail, high pressure oil pipe and injector, etc.

All right. Oil supply system of GW2.8TC supercharged * * rail diesel engine

The general layout is shown in figure 1.

Fuel supply, fuel supply advance angle and

The fuel supply law is mainly determined by ECU according to the position of accelerator pedal.

Sensor, engine speed sensor, air flow transmission

The output parameters of sensor and water temperature sensor are determined by fuel injection.

Solenoid valve control on the controller. Injection pressure is determined by ECU.

Under the working condition, it enters the metering ratio oil through the high-pressure oil pump.

Control solenoid valve.

X43 1 connection failure of special components of Great Wall Motor.

Diagnostic instrument, the ignition switch is turned on, and the engine diagnosis function is entered.

Yes, read the fault code and output no fault code; produce a flame (by striking flint)

After that, the engine idles until the water temperature rises, and the engine is read.

Power system data stream (***40), partial data

See table 1 for the process.

Analyzing the data stream, no obvious anomalies were found.

According to. Using the Engine Test function of the scan tool,

Cut off the oil one by one to judge whether each cylinder works normally.

The test results show that the four cylinders of the engine run well at idle speed.

Considering that the car is new, the engine is idling.

Smooth, good acceleration performance, no obvious abnormality in data flow,

However, the phenomenon of black smoke from the engine, coupled with the previous maintenance firewood,

Oil engine experience, decided to focus on checking the accelerator pedal position.

Sensor, coolant temperature sensor, fuel injector, EGR

Electromagnetic valve and EGR valve, turbocharger, etc.

Accelerator pedal position sensor check-connection failure

Obstacle diagnostic instrument, turn on the ignition switch and read its data stream.

In the process of never stepping on the accelerator pedal and fully stepping on the bottom,

Output voltage of accelerator pedal position sensor 1# potentiometer

The value gradually increased from 0.8V to 4V; 2# potentiometer output

The voltage value gradually increases from 0.4V to 2V; as time goes on

Fig. 1 GW2.8TC supercharged * * rail diesel engine oil supply system pipeline layout.

1- oil tank; 2- Fuel filter; 3- oil return valve; 4- oil return tee; 5- High pressure oil pump

Oil inlet metering proportional solenoid valve; 6-CP 1H high pressure oil pump; 7- Oil transfer pump; 8-*** rail pressure

Force sensor; 9- high voltage * * * rail; 10- syringe; 11-EDC16c39 electronic control unit

S E R V I C E C A S E S

Maintenance example

55

The output voltage of 1# potentiometer varies with the position of accelerator pedal.

This value is always twice the output value of 2# potentiometer. Impeccable

The test shows that the accelerator pedal position sensor has good performance.

Coolant temperature sensor check-turn off ignition switch

Switch, remove the water temperature sensor, and measure the plug on the harness side.

The voltage is 5v; The hot water temperature sensor measures its resistance value.

At 20℃, the resistance value is 2530Ω, and the resistance value is 2530Ω.

The resistance value is180Ω at 100℃. All measurements are positive.

Within the normal range.

Turbocharger inspection-this engine has adopted.

Exhaust gas turbocharger (supercharger is Mitsubishi)

TF035HM type, with the highest rotating speed of 180000r/min, the most

The high pressure ratio is 2), which is controlled by the mechanical exhaust valve.

Pressurize. Check the turbocharger turbine, compressor and lubrication.

Slip part, no abnormality found; Check the line with a manual vacuum pump.

Air release valve, good action.

EGR Solenoid Valve and EGR Valve Inspection -EGR

The solenoid valve has two terminals, which are controlled and measured by ECU.

Measure its resistance value, which is normal; Remove EGR and find the valve.

There is carbon deposit, but it is well sealed. Clean with carburetor cleaner.

The EGR valve, EGR solenoid valve and EGR valve should be cleaned.

faultless

Fuel injector inspection-the fuel injector is B O S C H.

CR 1P2, the specification of injector is 6×0. 137, electromagnetic.

The valve sensitivity is 0.2 ms Unplug the main relay and start the engine.

After the fire, when the engine naturally stops (depressurizes), turn off the engine.

Ignition switch, unplug the fuel injectors and measure each fuel injector.

The resistance of the coil is about 0.7 Ω, which provides power.

The voltage is 12.4V, which is normal; Remove high pressure

Found pipes, syringes, syringe nozzles.

Serious carbon deposition; Remove the lower body of the fuel injector and use the

Carburetor cleaning agent inspection found that all fuel injection.

The spray hole of the device is not blocked. Considering the nozzle

Serious carbon deposition, use special ultrasonic for diesel engine.

Wave cleaning instrument cleaned all syringes (note

Meaning: If a new fuel injector is replaced, it must be used.

Scan tool Match input.

Code of new fuel injector).

Up to now, the fault source has not been found.

Because. After reassembling the related components,

Start the engine and the fault still exists. At this moment,

Think about whether the fault is due to lack of fuel.

How about it? Ask the driver to know this.

Cars always add 0# firewood at Sinopec gas station.

Oil, never refuel at a small gas station. from

There is a mineral spring in the fuel filter pipe leading to the fuel tank.

Major, home, point, comment

As a maintenance technician, solve any faults,

First of all, we should comprehensively analyze the possibility of failure.

The reasons for the failure, and analysis according to the reasons for the failure.

Sex test. Although the car uses the latest electricity.

The diesel injection system that controls the * * rail has a black smoke fault.

It should still be poor combustion (diesel oil is not completely burned)

Result. We should start from this point first.

The possibility of failure is analyzed, not all at once.

Test the electronic control system. Automobile fault detection and

But not all systems and components of the vehicle.

Check it again, but analyze what to check and what not to check.

Check what? The author of this case is interested in the electronically controlled track system of * * * Group.

The detection of each part of He Cheng is introduced in detail.

Shao, just give readers some maintenance skills.

Technical data for readers' future reference.

In this case, the diesel engine emits black smoke from the root.

This analysis is nothing more than the following reasons: First,

It is insufficient cylinder pressure, poor compression and insufficient combustion;

Second, the diesel oil in the * * * rail has low pressure and poor atomization;

Third, the pressure in the * * * rail is on the high side, and there is too much oil injection and mixing.

Too much gas; Fourth, improper fuel injection timing or valve timing.

Mistakes; Fifth, the fuel injector is dirty, and the atomization of fuel injection is poor and mixed.

Insufficient gas formation; Six, the electronic control system related parameters.

Error (usually, the fault code will be recorded or downloaded from the data stream.

The problem can be found in); Seventh, the fuel quality is not good, firewood

The cetane number of the oil is not suitable or the diesel oil contains much gum.

Too much, easy to form carbon deposit. With the above analysis and

This is a new car that has only traveled 2300 kilometers, so it can be ruled out.

Possibility of mechanical problems; Pass fault code

And data flow can eliminate the problems in the electronic control system;

The only remaining problems are dirty fuel injectors and fuel quality problems.

Fuel quality problems are often easily overlooked by maintenance personnel.

A little. The author reminded me very much in the final summary of the article.

Well, Sinopec's diesel is indeed the same as PetroChina's diesel.

Difference, remind the majority of maintenance technicians to cause high weight.

See.

In addition, I want to say that I find a lot of maintenance.

During maintenance, personnel always repeat the test. For example, in this case,

The author detected the dynamic data stream with the detection instrument, and also knew it.

There are no obvious anomalies in the data stream, but the author still

Treat each sensor and actuator "honestly".

Okay, Cha, is that necessary? If you can find and ask

Problem, the data flow must be abnormal because

All the data are normal, which is enough to explain the sensor book.

There is nothing wrong with the fuselage and wiring, so there is no need to do it again.

"Honesty" should be tested one by one, and it is best to have that time.

Think more, think about problems, or listen romantically.

Just listen to the song! (Editor Liang You)

Table 1 GW2.8TC engine data flow (parts)

Parameter values of data flow items

Engine speed 799 rpm.

The rail pressure of the fuel system is 31.64mpa.

The set value of rail pressure is 30.95Mpa.

The maximum actual rail pressure is 31.42mpa.

The output voltage of the rail pressure sensor is1.20V.

At present, the fuel injection quantity of the system is 8.63mg/cyc.

The EGR rate required by the intake system is 60.78%.

The voltage value of accelerator pedal 1 potentiometer is 0.80V V v.

The voltage value of accelerator pedal 2 potentiometer is 0.39V V v.

The accelerator pedal degree before filtration is 0.00%.

The fuel injection quantity set by the system is 9.02mg/cyc.

The pre-control value of rail pressure controller is1.11cm3/s.

The oil supply setting value of the oil metering device is1.64cm3/s.

The duty cycle of the temperature signal output by the air mass flow sensor is 7.06%.

The low voltage output by the water temperature sensor is1.30v.

The engine cooling water temperature is 63.86℃

The battery voltage is14.47V.

The output duty ratio of proportional solenoid valve of fuel gauge is 20. 17%.

No diesel oil in the water bottle was found by naked eye observation. helpless

Next, I decided to try to replace PetroChina's 0# diesel. Jiangyuan

After all the fuel in the fuel tank is drained, add 10L PetroChina.

0# diesel oil, manually deflate the oil pump, and then start the engine.

Idle for about 5 minutes, slam on the accelerator and start.

The motive smoke actually returned to normal. The engine seems to be black.

The smoke fault is really rooted in the fuel quality. Two different manufacturers

The produced diesel oil is different in color and transparency.

Because there is no fuel detection means, it is difficult to analyze it in detail.

Cause of failure.

Maintenance summary

Recently, it has also been used in other regions.

GW2.8TC supercharged * * rail diesel engine was discovered.

If there is black smoke, replace PetroChina 0# diesel oil and clean it.

After cleaning the injector and EGR valve, the fault of black smoke accelerates.

It was eliminated. Some regions have already sent this information back to Zhong Shi.

Change. Please pay attention to fuel products when repairing such faults.

Quality can reduce detours.