Particulate emission from diesel engines is one of the most important pollutants in urban areas. With increasing worldwide regulatory requirements to lower particulate matter (PM) standards for heavy duty diesel powered vehicles, the interest in diesel particulate filter based emission control solutions such as the Continuously Regenerating Technology (CRT®) have significantly increased. This system has been applied to thousands of heavy-duty diesel vehicles in Europe over the last six years to meet various local and governmental requirements, while recently introduced in the US.
Among the numerous demonstration programs taking place in the US, one important one is the evaluation of CRT filter systems on urban transit buses in NY City. Here, several NY City transit buses with DDC Series 50 engines have been equipped with CRT filters and operating on ultra low sulfur diesel (< 30 ppm S) in transit service in Manhattan since February 2000. Emission testing results from this program have shown >90% reduction in PM and CO and > 80% for HC with the CRT system after 12 - 16 months of operation. The on-road operational data demonstrated very durable and near maintenance-free operation of the CRT system. Under similar test programs in California, CRT systems have also been successfully evaluated on transit buses and grocery trucks for over 16 months of operation.
A selection of CRT filters were removed from the field in Europe, after high road mileage accumulation, up to 600,000 km and tested for performance on a diesel engine on a dynamometer. The test results demonstrated the CRT filter system achieving high durability and up to 95% PM reduction.
In this paper, the emission performance and durability data of the CRT filter system will be discussed from these different applications in the US and Europe.
These results have demonstrated that the CRT filter system has been proven to be highly effective and robust and it is anticipated that this technology will be applied worldwide to meet the increasingly stringent emissions requirements from diesel engines.