Current catalytic formulations for motorcycles consist of so called three way catalysts (TWC) that are able to reduce the emissions of carbon monoxide (CO), nitrous oxides (NOx) and hydrocarbons (THC) below the regulatory emission limit. These catalysts mostly contain platinum (Pt), palladium (Pd) and rhodium (Rh), also called platinum group metals (PGM) in different ratios and concentrations. Another important component is the so-called oxygen storage material (OSC) that is compensating fluctuations in lambda during acceleration and deceleration.
Currently existing catalyst formulations must be modified to fulfill the more stringent emission limits with simultaneous consideration of a more realistic test cycle. In this paper we will present the modification of an existing catalytic formulation for a 690 cm3 motorcycle from model year 2012. The motorcycle is equipped with a quick-change muffler to be able to compare different formulations in a simple way. The motorcycle was used off-shelf, during our tests no modifications of the ECU or the engine mapping haven taken place. Basically this motorcycle was used as a reference source of emissions to be able to compare the performance of different catalyst formulations. We will also show data of a modified formulation after an in-service durability run on a motorcycle from model year 2014 using the same engine as our testing motorcycle.
By changing the catalyst formulation, we will show that we were able to modify the catalyst to fulfill Euro IV by keeping catalyst size and total platinum group metal content on a Euro III level.