Control System Packaging/Impact on Performance – Some have argued that catalyst systems cannot be readily utilized on motorcycles because of packaging constraints associated with the limited space available on the vehicle to install the device, the greater space velocity through the catalyst compared to an automobile traveling at the same speed, and the potential backpressure build-up that could adversely affect performance. Packaging is an engineering challenge, but experience in related applications has clearly demonstrated that these challenges can be met. This is demonstrated by the fact that catalyst technology has been successfully designed, packaged, and equipped on over 15 million motorcycles worldwide.
Catalyst formulations and substrate designs have been developed, and continue to advance, which maximize emission control performance for small and larger SI engines like those used on motorcycles while minimizing the impact on backpressure and vehicle performance (see e.g., SAE Paper Nos. 2001-01-1821 and 2001-01-3814). A wide variety of concepts have been commercially applied to address the issue of limited space available on smaller vehicles. For example, in the case of on-road motorcycles and mopeds, packaging techniques have included placing the catalyst within the muffler system, mounting the catalyst close to the manifold, and using catalyst-coated plates and tubes, including flexible tube designs for exhaust pipes. These types of packaging strategies do not add any volume or complexity to the vehicle.
Operator Safety – Contrary to the claims of some, catalyst-based systems can be easily and safely applied to motorcycles. Indeed, the 10 year experience with on-road motorcycles and mopeds is proof of this fact. The countries that have successfully implemented catalyst-based regulatory programs have not identified any special safety issues associated with the use of catalyst technology on motorcycles and mopeds in real world applications. This fact is particularly significant given that it is not uncommon in India or Southeast Asia for catalyst- equipped motorcycles to carry two to four riders in all manner of attire.
September 17, 2002