The 28 Questions You Must Know When You Repair Common Rail System Cars
With the diesel fuel technology increasingly mature and perfect, the diesel engines also occupy an increasing market share and diesel common rail vehicle maintenance industry also came into being. In the maintenance process, we will meet a variety of various types of failures and problems, and some problems we must know as a common rail industry maintenance staff. Now ERIKC sort out the 28 questions you must know when you repair common rail system cars, hope it can help you.
1> The performance of pull out the fuel metering unit?
All the fuel go into the common rail tube leads to the rail pressure over high, pressure limiting valve opens and enters the limping mode. It is also easy to cause oil temperature rising, not good to the whole system. PRV valve frequent opening will affect the system life. You need to plug in the fuel measurement unit, and re-start car.
2>The effect of accelerator when the car in limping mode?
The accelerator works, but the power can not pull on, rotating speed can only go to1500 rpm.
3>What is the maximum, minimum, and normal value of the pressure and temperature after through intercooler?
The pressure and temperature are closely related with the engine emissions and performance after after through intercooler, the specific values can reference the technical center laboratory bench test data. Generally speaking, under the rated conditions, 240Ps, after the cold pressure is 110kPa, 360Ps after cold pressure is160kPa, temperature 55 ± 5 ℃.
4>The density of the gas before and after the intercooler?
We generally only focus on pressure, temperature, volume, PR / V = constant, which is the general equation.
5>What is the maximum, minimum, and normal value of oil pressure and temperature?
Normal operating oil pressure range (oil temperature ≥ 80 ℃) ... ... ... ... .100 - 600kPa
Diesel engine start instantaneous oil pressure peak. .................................. 1000kPa
Normal operation of the minimum oil pressure
-The rated condition .................................... ... ... ... ... ... ... ... ... ... ... ... 380kPa
- Maximum torque conditions ......................................................... ..... ... 250kPa
- Idle conditions ....................................................................................... 100kPa
Oil pressure alarm value ........................................................................... 60kPa
The maximum temperature of oil in the main oil passage ........................... 100 ℃
The maximum temperature of oil in oil tank ........................... ....................120 ℃
6>What is the maximum, minimum, and normal value of water?
Water temperature normal value of 80-95 degrees, 85 degrees is easy to accept the temperature of the driver
Allow the maximum temperature of the diesel engine coolant outlet (alarm temperature) ... .. 96 ℃
Recommended minimum temperature of diesel engine coolant outlet ........................ .......... 60 ℃
Short time to allow the maximum temperature of the coolant .................. ... ... ... ... ... ........ 105 ℃
7>What are the oil requirements for engine oil and diesel?
Diesel Engine Lubricant Oil Grade (GB11122-1997) CF Grade
Fuel grade (GB252-2000)
Should Europe Ⅲ have special requirements for diesel? (Yes. There are several indicators, such as sulfur content, polycyclic aromatic hydrocarbons and other factors affecting emissions. For details, please reference the emission standard GB17951-2005)
8>What is the principle and testing standard for all sensors?
testing method:
--first check whether the circuit, and then check whether the short circuit;
--Check the size of the resistance (the size of the resistance is the number of specific?)
9>What is the fuel injector control strategy?
Duty cycle output
10>Synchronous signal principle
Determine the ignition position (crankshaft position, cylinder)
11>Can pumps provide pressure? Is there a check valve for low pressure oil
<9 bar absolute pressure (Euro III); there is a one-way valve in the hand pump
12>What's the fuel injection hole of fuel injectors?
Roughly within 20 wires (<0.2mm). We judge the injector from the flow, such as 860ml / 30sec. In a rail pressure, spray 860ml diesel in 30 seconds.
13>How much water temperature can be started (if the temperature is too low, easy to cause pull cylinder)?
Generally require the user to start the engine after the first idle run 2-3 minutes, the oil pressure should be higher than 100kPa, when the water temperature is not higher than 60 ℃ do not suddenly rapid high-speed heavy load operation. When the water temperature is too high, it is lack of cooling capacity, also easy to pull the cylinder.
14>How much air intake of air filter ? What is the limit value?
The driver felt refueling, black smoke would think of replacement, or have an experienced mileage. Rarely to detect.
There are two concepts here, one is the actual air intake of air filter, that is the engine air intake, and the other is the air filter rated air intake, in general, the rated air intake will be greater than the actual intake air volume
Recommended rated flow rate for air filter ........................ ..... ≥ ≥ 1400 m3 / h
When the air filter resistance is greater than 6kPa should be cleaned or replaced air filter cartridge
15>If the injector terminal has positive and negative?
No
16>What is the pressure difference of intercooler?
Normal 4-7KP. The intercooler pressure drop should not be greater than 12kPa
17>The cause of piston roofing?
In generally, we considered that the injector atomizer is not well and burns abnormally at the top of the piston, resulting in the gradual development of the high temperature on the top of the piston.
18>What is the amount of oil consumption?
Oil to diesel consumption ratio: 4: 1000
MAN ratio: 10: 1000
GB standard vehicle diesel engine rated working hours when the oil and diesel consumption ratio of not more than 0.2%.
At Euro III, the oil consumption conference affects particulate emissions
19>The high pressure oil circuit in common rail tube after parking?
In general, the oil leak from the fuel injectors.
20> Does the battery loss affect the ECU's work?
The normal working range for ECU is 6V-32V, the battery is the biggest impact on the starter, will cause the starter can not work properly.
21>What is the speed when the starter starts?
200r/min
22>If the KTS can detect it if the engine 6 tanks all leak?
If a cylinder leaks can be tested by compression test.
By comparing with the speed of other engines to determine the six tank leak situation.
23>If there is automatic oil off function if the high-pressure tubing broken?
No.
24>Is the power of the exhaust brake valve electric or compressed gas?
Compressed gas
25>Does the break of Double brake installed in the same gas road? Is it a pneumatic switch?(For some car, front and rear wheels are braked)
A mechanical switch mounted on the same gas path
26>The installation location of clutch switch and brake switch?
Under the clutch and brake switch
27>Does the exhaust brake have a big damage for supercharger and engine?
It has little damage if use normally
28>The cooling circuit of the ECU is a straight pipe, is the cooling effect obvious?
As the fuel continues to flow, the temperature is low, the cooling effect is obvious.
The pressure and temperature are closely related with the engine emissions and performance after after through intercooler, the specific values can reference the technical center laboratory bench test data. Generally speaking, under the rated conditions, 240Ps, after the cold pressure is 110kPa, 360Ps after cold pressure is160kPa, temperature 55 ± 5 ℃.
4>The density of the gas before and after the intercooler?
We generally only focus on pressure, temperature, volume, PR / V = constant, which is the general equation.
5>What is the maximum, minimum, and normal value of oil pressure and temperature?
Normal operating oil pressure range (oil temperature ≥ 80 ℃) ... ... ... ... .100 - 600kPa
Diesel engine start instantaneous oil pressure peak. .................................. 1000kPa
Normal operation of the minimum oil pressure
-The rated condition .................................... ... ... ... ... ... ... ... ... ... ... ... 380kPa
- Maximum torque conditions ......................................................... ..... ... 250kPa
- Idle conditions ....................................................................................... 100kPa
Oil pressure alarm value ........................................................................... 60kPa
The maximum temperature of oil in the main oil passage ........................... 100 ℃
The maximum temperature of oil in oil tank ........................... ....................120 ℃
6>What is the maximum, minimum, and normal value of water?
Water temperature normal value of 80-95 degrees, 85 degrees is easy to accept the temperature of the driver
Allow the maximum temperature of the diesel engine coolant outlet (alarm temperature) ... .. 96 ℃
Recommended minimum temperature of diesel engine coolant outlet ........................ .......... 60 ℃
Short time to allow the maximum temperature of the coolant .................. ... ... ... ... ... ........ 105 ℃
7>What are the oil requirements for engine oil and diesel?
Diesel Engine Lubricant Oil Grade (GB11122-1997) CF Grade
Fuel grade (GB252-2000)
Should Europe Ⅲ have special requirements for diesel? (Yes. There are several indicators, such as sulfur content, polycyclic aromatic hydrocarbons and other factors affecting emissions. For details, please reference the emission standard GB17951-2005)
8>What is the principle and testing standard for all sensors?
testing method:
--first check whether the circuit, and then check whether the short circuit;
--Check the size of the resistance (the size of the resistance is the number of specific?)
9>What is the fuel injector control strategy?
Duty cycle output
10>Synchronous signal principle
Determine the ignition position (crankshaft position, cylinder)
11>Can pumps provide pressure? Is there a check valve for low pressure oil
<9 bar absolute pressure (Euro III); there is a one-way valve in the hand pump
12>What's the fuel injection hole of fuel injectors?
Roughly within 20 wires (<0.2mm). We judge the injector from the flow, such as 860ml / 30sec. In a rail pressure, spray 860ml diesel in 30 seconds.
13>How much water temperature can be started (if the temperature is too low, easy to cause pull cylinder)?
Generally require the user to start the engine after the first idle run 2-3 minutes, the oil pressure should be higher than 100kPa, when the water temperature is not higher than 60 ℃ do not suddenly rapid high-speed heavy load operation. When the water temperature is too high, it is lack of cooling capacity, also easy to pull the cylinder.
14>How much air intake of air filter ? What is the limit value?
The driver felt refueling, black smoke would think of replacement, or have an experienced mileage. Rarely to detect.
There are two concepts here, one is the actual air intake of air filter, that is the engine air intake, and the other is the air filter rated air intake, in general, the rated air intake will be greater than the actual intake air volume
Recommended rated flow rate for air filter ........................ ..... ≥ ≥ 1400 m3 / h
When the air filter resistance is greater than 6kPa should be cleaned or replaced air filter cartridge
15>If the injector terminal has positive and negative?
No
16>What is the pressure difference of intercooler?
Normal 4-7KP. The intercooler pressure drop should not be greater than 12kPa
17>The cause of piston roofing?
In generally, we considered that the injector atomizer is not well and burns abnormally at the top of the piston, resulting in the gradual development of the high temperature on the top of the piston.
18>What is the amount of oil consumption?
Oil to diesel consumption ratio: 4: 1000
MAN ratio: 10: 1000
GB standard vehicle diesel engine rated working hours when the oil and diesel consumption ratio of not more than 0.2%.
At Euro III, the oil consumption conference affects particulate emissions
19>The high pressure oil circuit in common rail tube after parking?
In general, the oil leak from the fuel injectors.
20> Does the battery loss affect the ECU's work?
The normal working range for ECU is 6V-32V, the battery is the biggest impact on the starter, will cause the starter can not work properly.
21>What is the speed when the starter starts?
200r/min
22>If the KTS can detect it if the engine 6 tanks all leak?
If a cylinder leaks can be tested by compression test.
By comparing with the speed of other engines to determine the six tank leak situation.
23>If there is automatic oil off function if the high-pressure tubing broken?
No.
24>Is the power of the exhaust brake valve electric or compressed gas?
Compressed gas
25>Does the break of Double brake installed in the same gas road? Is it a pneumatic switch?(For some car, front and rear wheels are braked)
A mechanical switch mounted on the same gas path
26>The installation location of clutch switch and brake switch?
Under the clutch and brake switch
27>Does the exhaust brake have a big damage for supercharger and engine?
It has little damage if use normally
28>The cooling circuit of the ECU is a straight pipe, is the cooling effect obvious?
As the fuel continues to flow, the temperature is low, the cooling effect is obvious.
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