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AECC

Association for Emissions Contol by Catalyst

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Two-and three-wheelers

Motorcycles and mopeds

The emissions regulations for motorcycles and mopeds also cover on-road tricycles and quadricycles. They therefore include vehicles such as the small 3-wheel light trucks used in some parts of Europe. Euro 4 requirements were introduced from 2016 and, subject to an environmental study by the European Commission, a Euro 5 stage is planned in 2020.

2-stroke petrol engines and diesel engines

The emissions limits for this class of vehicle fitted with 2-stroke petrol engines or diesel engines are such that they may not require emission exhaust gas aftertreatment. Nevertheless, it is possible to use oxidation catalysts (or diesel oxidation catalysts) with these engines.

4-stroke petrol engines

Historically, motorcycles for the European market have used either oxidation catalysts or three-way catalysts to meet the emissions regulations. Since the introduction of Euro 3 in 2006, all new 4-stroke motorcycles have been equipped with three-way catalysts.

The principle of operation of these catalysts is the same as for car engines. For the three-way catalyst the exhaust system will include an oxygen sensor or air:fuel ratio sensor that monitors the oxygen content of the exhaust and continuously adjusts the fuelling to match the conditions. This also ensures that the system alternates rapidly between very slightly fuel-lean and very slightly fuel-rich conditions. In this way both the oxidation functions (conversion of CO and HC into CO2 and water) and the chemical reduction function (NOx into nitrogen) can operate simultaneously. For motorcycles, of course, space is a limiting factor. The catalyst generally has to be quite small and built into a short exhaust pipe. Metal substrate catalysts are often used in this type of application.

  • Position Papers
  • Presentations
  • Scientific Publications
01.02.2011

AECC comments on European Commission proposal for Regulation on approval and market surveillance of two- or three-wheel vehicles and quadricycles

30.11.2011

Regulated and Non-Regulated Emissions of Selected State-of-the-Art European Mopeds, SIA conference, Strasbourg

13.05.2011

Particle Emissions of Powered Two Wheelers, Cambridge Particles Meeting

22.03.2011

Emissions of Motorcycles and Mopeds, Public Hearing on “Clear Internal Market rules for mopeds, scooters & motorcycles”, European Parliament, Brussels

02.04.2009

AECC – Ricardo Poster Regulated and Unregulated Exhaust Emissions Performance of 5 Modern Motorcycles over Euro 3 & WMTC Test Cycles, CAPoC8 Conference, Brussels

02.10.2008

AECC Summary on the 2008 AECC Motorcycle programme for the MVEG Motorcycles meeting, Brussels

01.12.2011

Regulated and Non-Regulated Emissions of Selected State-of-the-Art European Mopeds, SIA conference, Strasbourg

17.06.2009

An Emissions Performance Evaluation of state-of-the-art Motorcycles over Euro 3 and WMTC Drive Cycles, SAE Fuels & Lubes Conference, Florence

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