Wednesday, 16 November 2016

The AdBlue (part II)

After having started in the above mentioned topic in this blog (consult "the AdBlue, now also 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.

Thursday, 10 November 2016

Performance of the energy recovery system of the BMW Series 1

The principle of energy recovery is based on fuel economy during engine start up and a reduction in polluting emissions from the exhaust gases. In this way, according to the driving profile, we can save up to 3% of CO2 and thus save energy.

This system is applied to the intelligent regulation control system of the alternator, also known as the IGR system by BMW.

Operating principles

Operating principles

The application of strategies in the battery charging regulation system which enables the battery to be charged only up to a defined measurement and depending on the different environmental conditions such as the outdoor temperature, the temperature inside the battery, the age of the battery, battery charge, etc. 

In this way, the constant regulation of the system prevents energy being wasted while the engine is running without repercussions on the thermal efficiency of the latter.

Operating phases

Energy recovery is carried out during the vehicle's
propulsion phases. At this time, the alternator is fully activated and generates the electrical energy that supplies the battery. Once the vehicle is launched, it does not consume fuel as the kinetic energy acts from the vehicle under propulsion to the alternator passing through the wheels and engine.

However, during the acceleration phases of the vehicle the alternator is not activated, therefore it does not use any power or fuel to produce electrical energy.

Wednesday, 2 November 2016

Noise in gearbox after engaging 5th gear

This post discusses a fault that causes a noise in the area of the vehicle's gearbox when driving on the road, until eventually the 5th gear cannot be engaged.

Affected models 
The engines motors that could be affected are the following:

Noises in the gear shifting area when driving the vehicle, regardless of the speed at which it is driven.
Problems engaging 5th speed.
Gearbox oil leak

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