DI Two Stroke Engine Catalyst Development for 2 wheelers application 2001-01-1847

New legislation on two wheelers pollutant emissions has forced two stroke engine manufacturers to study the DI technology. Piaggio scooter ET2 Injection is the first two wheelers engine in mass production, using a Direct Injection two stroke 50 cc engine. This DI engine, using the FAST system, strongly decreases the pollutant emissions and increases the engine efficiency.

Piaggio was the co-ordinator of the DOLCE project (Development Of innovative Low pollutant, low noise, low fuel Consumption two stroke spark ignition Engines for future vehicles for individual urban mobility) supported by the European Commission where ROSI and IFP have worked together on the optimisation of the catalyst system design of this engine. This project has been completed in 2000.

For a such a DI 2 stroke engine, exhaust gas can be very lean. To optimise the catalyst after treatment, several catalyst precious metal (PM) loads and configurations (size, density,…) have been tested on a Piaggio 125 cc FAST engine, set up on a dyno test bench where it was possible to reproduce equivalent R40 ECE driving conditions.

Influence of hot tubes or coated wall on the catalyst efficiency and on the catalyst temperature has been investigated.

The main work has been focused on HC and CO efficiency but the catalytic behaviour for NOx has also been investigated, DI 2 stroke engines producing more NOx than carburetted engines.