Timing belt kit CT 1077K2/WP2 for Opel, Alfa, Fiat, Saab, Chevrolet Various 1.6/1.8 models from 2003 onwards

Problem: 

The tensioning pulley supplied differs visually from the pulley fitted in the vehicle. 

Cause: 

ContiTech supplies two different versions of the tensioning pulley, with and without pin KM-6333. The two designs differ in their fitting, but they can both be used without reserve.

Solution: 

Variant 1 
The version without a pin has to be tightened clockwise initially using a 6mm hex key after mounting on the engine (20Nm + 120°) to enable the belt to be fitted. Once the hex key is removed, the tension is automatically set. 


Variant 2 
In the version with a prefitted pin, the pin is only withdrawn once the belt has been fitted. Here, too, the tension is then automatically set. 

(Content protected by copyright)                                  

AdBlue (part II)

After having started in the above mentioned topic in this blog (consult "AdBlue for passenger cars "), on this occasion, we intend to elaborate on the structure and operation of the analysed system adopted by the different manufacturers in their vehicles.

Each manufacturer "baptises" their NOx treatment system for the diesel engine with a commercial name, normally under the umbrella of the word “Blue”.

It is worth mentioning that some makes/brands, such as Volkswagen, Audi, and Seat do not assign any name that is visible in the vehicle logo.

Reducing agent:As noted on previous occasions, the AdBlue reducing agent is based on an aqueous solution consisting of a 32.5% urea and 67.5% water. This compound is not dangerous to people or the environment.
However, included in the features of this product we highlight two peculiarities capable of generating problems:
-Due to its high water content it freezes at -11°C.
-In contact with the air, the Adblue tends to crystallize and can cause blockages in pipes and ducts.

Summary of the operation: 
As you know, the AdBlue reducing agent is dosed directly into the exhaust pipe thanks to the electronic injector. With the exhaust temperature, the additive is transformed into ammonia and enters the SCR reduction catalytic converter. This takes care of removing the NOx by chemical reaction, transforming them into nitrogen and water. The NOx sensor located at the output of the SCR checks there are no nitrogen oxides present at the output.

Features of the system 

Exhaust line:
In the exhaust line, manufacturers tend to use the same structure (injector, particulate filters and SCR). Here we find a difference in the French PSA group, who first mount the SCR and then the particulate filter.

Additive tank: 
Usually integrated into the tank is the pump-gauge, which is for measuring the volume of the tank and pumping the reducing agent at sufficient pressure to the exhaust pipe injector.

The assembly includes the following components:

- Reducing agent level sensor.
- Reducing agent pump
- Switch valve for the reducing agent.
- Reducing agent pressure sensor.
- Reducing agent temperature sensor.

Reducing agent level sensor: 
Determines the volume of AdBlue contained in the tank. Normally it discriminates between three volumes and there is no indicator “needle” on the instrument panel, the driver is warned via a warning or indicator on the multi-function display.

Electric pump for reducing agent: 
The pump sucks the additive from the tank and pumps it at a pressure of between 4 and 6 bar to the injector. This does not work continuously, it only works when it is necessary to inject additive. Some systems include a accumulator so there is immediate pressure at the start of the injection.

Switch valve for the reducing agent: 
The fact that the AdBlue freezes means that protection measures have to be incorporated into the additive circuit.
The switch valve is one of these measures. When the engine stops, the pump starts up and the switch valve changes the direction of flow of the reducing agent, collecting the liquid from the injector duct and draining it back into the tank.

Reducing agent pressure sensor:
This is a conventional pressure sensor which transmits the pressure information via a variable voltage signal.

Reducing agent pressure sensor 
Its signal ranges between 0.5 and 4.5 volts, the higher the pressure the higher the voltage.

Reducing agent temperature sensor: 
Of the NTC type, this temperature sensor is immersed in the additive reservoir. Its information is used to control the heating system for the additive system.

Heating circuit: 
To combat the problem of the product freezing, the additive circuits are protected by a heating system which starts up when the temperature is low.
The heating is distributed into three branches that can be activated independently:
-Additive pump heater: there is an electrical resistor inside the pump capable of heating the component.
-Tank heater: a resistor is immersed in the tank to prevent the stored AdBlue product from freezing.
-Reducing agent lines: the whole length of the pipe is protected by a heating resistance.

Reducing agent injector:
The additive process finishes when the reducing agent is dosed into the exhaust. The injector is controlled from the injection unit and when it opens it receives an electrical signal for its activation.

NOx sensor: 
After the SCR catalytic converter, the NOx sensor measures the efficiency of the system. If this compound is present at the output, the engine fault light comes on and indicates a fault in the SCR system.

Starting lock 
The EU VI anti-pollution regulations require that whenever a vehicle uses an additional reactive agent for treating exhaust gases, the engine starter can be locked whenever there is no reducing agent or any fault that could cause the vehicle to pollute more than specified by the standard.
As the reducing agent is used up the driver is advised with different alert levels:
Alert at 2400 km: this is the first indication, advises of the remaining range, once this alert has been given it is repeated every 100 km.
The yellow SCR system indicator lights up permanently.
1000 km indication: indicates the remaining range. Warns the driver that if the level is not reset it will not be possible to start the engine once it has stopped.
The warning is repeated every 50 km.
The SCR system indicator light is yellow and flashing.
Indication of absence of reducing agent: indicates prohibition on starting the engine.
The SCR system indicator is permanently red.

It is possible to cancel the engine start lock with the diagnostic tool in order to drive 50 km to take the vehicle to the workshop.


Generally, if the last warning has been given, the system requires an adaptation process with the diagnostic tool.

(Content protected by copyright)

AdBlue for passenger cars

On 1 September 2014, the Euro 6 European anti-pollution standards came into force, and on this occasion there were new stipulations relating to the reduction of emissions for light vehicles with a diesel engine. 

See where the change is:

(Comparison between the EURO 5 and EURO 6 standards)

As can be seen in the graphics, the new EURO 6 standard has evolved with the objective of substantially reducing nitrogen oxides (NOx).

Nitrogen oxides (NOx) and the diesel engine

The diesel engine, due to its operating characteristics, generates a high level of
NOx, as this gas is generated under high pressure and temperature conditions.

From some time now exhaust gas treatment systems have been used, one of the best known by professionals in the sector is the exhaust gas recirculation system EGR, this consists of reducing the creation of nitrogen oxides (NOx), by introducing burnt gases from the exhaust into the cylinder.

With the new emission limits required by EURO 6, many engines (especially larger capacity engines) will not achieve the target required by the standard.

AdBlue, the solution for NOx

This technology started in the industrial, agricultural and heavy machinery vehicle sector, and is the same system (with just small differences) that is currently installed in passenger cars and light commercial vehicles.

AdBlue is an additive in the form of an aqueous solution made up of 32.5% urea and 67.5% water. This is not a flammable product, it is safe to handle and in general is not a hazardous substance for people or the environment.

The components:

Additive tank: this has a capacity of approximately 20 litres and is usually located under the vehicle next to the fuel tank, it can also be located in the cavity left by the spare wheel.
Internally, the tank has a built-in pump, a level gauge and an electric heating system.

Injector: this is installed in the exhaust line, it is controlled electrically by the control unit and is responsible for dosing the additive directly into the exhaust.

SCR catalytic converter: This is a "Selection Catalytic Reduction" type converter, it is a ceramic monolith inserted in the exhaust pipe that can be located before or after the particulate filter.

SCR catalytic converter

Warning! The SCR catalytic converter does not have anything to do with the particulate filter:
The particulate filter (FAP) is responsible for removing the particulates.
The catalytic converter (SCR) is responsible for removing the NOx.

It facilitates the chemical reaction that will remove the nitrogen oxides generated by the combustion of the diesel oil.
                   
Nitrogen oxide (NOx) sensor: this sensor can detect the presence of NOx. It is installed downstream of the SCR catalytic converter in order to verify that there is no NOx at its outlet.

If the AdBlue system malfunctions in any way and NOx is emitted, the sensor detects it and informs the system's control unit.

Nitrogen oxide sensor

The NOx sensor has an integrated electronic module (inseparable assembly).

Control unit: this is the electronic unit that manages the system. Unlike in industrial and agricultural vehicles where this is a separate unit, in passenger cars, the AdBlue management functions are integrated into the same unit as that for engine control.

Operation:

The operation of the system is very simple and with few complications.
The process is started when the exhaust gas is hot (approximately 200°C), from this moment the control unit activates the electric additive supply pump (fitted inside the tank), which ensures the correct supply of additive to the injector.

When the unit activates the injector's electric control, it dispenses the amount required into the exhaust pipe (approx 1 litre of additive every 1000 km).

A chemical reaction takes place inside the exhaust pipe and the additive (AdBlue) undergoes a transformation which produces ammonia (NH3).

The exhaust gases and the ammonia (NH3) enter the reduction catalytic converter (SCR), the ammonia reacts with the nitrogen oxides (NOx) and transforms them into nitrogen and water.

System settings:

The additive tank empties over the miles and the vehicle user will be informed via a message on the instrument panel that varies depending on the range.

AdBlue information displayed on the instrument panel

As you can see, if the driver ignores the warnings, eventually the starting of the engine will be prevented.

Depending on the manufacturer and the current warning level, the system will normally have to be reset by means of a suitable diagnostic tool (after filling the additive tank).

(Content protected by copyright)