Silencer

Adequate catalytic converter volume.
Precious-metal coating.


Catalytic converters clean

Catalytic converters treat exhausts and are thus vital to humans and the environment. Indispensable for effective pollutant conversion is an adequate catalytic converter volume and a suitable coating of noble metals. ERNST guarantees them – as the result of an uncompromising premium strategy that knows only one goal: maximum customer satisfaction.

Whether casing, absorbent mat, heat shield or coated monolith, all components of ERNST catalytic converters are subject to stringent control by the ERNST quality assurance people. Premium technology which meets all demands on the performance, efficiency and reliability of a catalytic converter also essentially conduces to a long service life for the entire exhaust system.

Three-way catalytic converter

Based on the specific combustion process of the petrol engine, the three-way catalytic converter with lambda control (lambda (λ) = 1) enables both the oxidation of carbon monoxide (CO) and hydrocarbons (HC) and the reduction of nitrogen oxides (NOX). The very precise control systems of petrol engines employ lambda sensors.

State-of-the-art vehicles frequently are fitted with two sensors. The first, positioned upstream of the three-way catalytic converter, detects the oxygen content of the exhaust gas for the purpose of primary mixture control. A second sensor downstream of the catalytic converter determines the condition of the exhaust gas subsequent to treatment and, in consequence, the effective catalytic activity of the catalytic converter.

Show diagram "Air/fuel ratio lambda"

Oxidation catalytic converter

The oxidation catalytic converter for diesel engines effectively oxidises carbon monoxide (CO) and hydrocarbons (HC). However, since the combustion process involves excess air, i.e., lambda (λ) > 1, and the exhaust gas thus has a high residual oxygen content, reduction of the nitrogen oxides (NOX) is not possible.

NOx catalytic converter

In order to achieve nitrogen reduction in spite of this, in engines operating with excess air (λ > 1) – direct-injection petrol and diesel engines – storage catalytic converters are used. But they function optimally only within a limited temperature range which requires special temperature management.

Particulate filter

To minimise particulate emissions (soot), suitable filters are used in the exhaust system. These systems require careful matching of the exhaust system to the engine and the engine management system.