Three-way converters unlimite

This sort of catalytic converter is made for gasoline engines. At operating temperature, it converts the next substances:

1. unburned hydrocarbons (HC) into carbon dioxide (CO2) and water vapor (H2O)
2. Carbon Monoxide (CO) to Carbon Dioxide (CO2)
3. Nitrogen oxides (NO, NO2) in nitrogen (N2) and oxygen (O2)

These three processes take place simultaneously in theconverters unlimited . It is therefore referred to as a three-way converters unlimited.

A three-way converters unlimited needs a specific exhaust gas composition. Only this way can it unfold its full effect. Exactly just as much oxygen must certanly be released as must oxidize the hydrocarbons and carbon monoxide. This occurs when one the main fuel is mixed with 14.7 parts of air and burned in the engine. This is referred to as a so-called “stoichiometric mixture” (lambda = 1). So as to do this mixture, the lambda probe placed between the engine and the catalytic converter measures the remainder oxygen content in the exhaust gas. The engine control processes the measurement result and gives the control impulses for optimal mixture formation.

With the obligatory introduction of the EURO 5 emissions legislation since January 1st, 2011, new developments in the field of converters unlimited became necessary. Modern three-way catalytic converters now warm up in just a few seconds. This so-called “light-off” behavior is supported by the use of special coatings.

Along with the coating concepts, structurally demanding catalyst geometries (“close couple” or systems near to the engine) are increasingly being used. And also this includes so-called “manifold converters unlimited” in that your converters unlimited and the exhaust manifold form a unit.

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With the exhaust gas concepts mentioned, the hot exhaust gases from the combustion notion of the engine are routed straight into the converters unlimited . The enormous temperatures in the output section of ​​the engines or turbochargers cause temperatures all the way to 1,000 °C.

Another special feature may be the high acceleration forces. As a result of direct connection between the engine and the exhaust system, these could be up to 75g. These new designs need to be adapted when it comes to flow technology. This is necessary to guarantee the inflow of the built-in exhaust gas sensors at all times and thus to provide the control units with the necessary information on temperatures, exhaust gas compositions, and back pressures.

safety

In the case of converters unlimited that use ceramic monoliths, so-called “mounting mats” are used to fix the carrier. These protect the converters unlimited  from impacts and seal off secondary exhaust gas flows. To date, fine ceramic fibers suspected to be carcinogenic have been used in many cases. A so-called “green mat” was introduced to make sure a high level of environmental compatibility. These may have two properties: either they are made of biosoluble fibers that are quickly dissolved in body fluids in order that they do not cause any damage to the organism, or they can not get into the lungs for their size.

value retention

converters unlimited are subject to a natural aging process and have a typical service life of 80,000 to 100,000 km. High temperatures (up to over 800 °C) and mechanical loads (vibrations) contribute to the during normal driving. Because of these factors, the precious metal-containing coating of the carrier could be lost over time.

As well as the contact of the converters unlimited  when driving over obstacles, the next factors can cause premature aging of the converters unlimited

converters unlimited POISONING

If the engine burns too much oil, the additives contained in it can deposit on the catalyst surface and lock it. The exhaust gases can’t reach the precious metals and the converters unlimited loses its function.

Another basis for catalyst poisoning may be short trips. In this instance, however, the converters unlimited can be regenerated by driving longer on the motorway.

Leaded gasoline is employed to cause poisoning. Today, however, this could only happen once you refuel abroad. To avoid this, care should be used to ensure that unleaded fuel (unleaded; sans plomb) is used.

MELTING OF THE converters unlimited

Faults in the ignition or mixture preparation system may result in an unburned fuel-air mixture entering the catalytic converter and burning on the converters unlimited surface. The temperatures in the converters unlimited can rise to over 1000 °C. This destroys the catalyst support. Faults in the ignition or mixture preparation should therefore be rectified immediately in a specialist workshop.

environmental Protection

Modern exhaust after treatment systems make a major contribution to the noticeable improvement in health conditions. The combustion process in the engine produces the following pollutants along with the primary elements water (H2O), co2 (CO2), and nitrogen (N2):

•  carbon monoxide (CO)
• hydrocarbon (HC)
• Nitrogen Oxide (NOX)
• sulfur dioxide (SO2)
• Particulate matter (PM) – primarily from diesel engines

With the increasing tightening of national and international emission and immission regulations, further optimization of engine measures is essential. Additionally, the usage of complex exhaust gas after-treatment systems is important to meet the limit values. A technically optimized converter, which brings the car in to a higher emission standard and can thus also give the vehicle owner a tax advantage, increases the resale value of the vehicle.

catalyst pictures

• Image 1: Catalyst ©Eberspächer

• Image 2: Particulate filter ©Eberspächer

• Figure 3: Catalyst diagram

• Figure 4: Manifold catalytic converter

Select a picture to enlarge it.