CDTi’s Purifilter™ EGR diesel particulate filter, an update to the technology on its Purifilter™ model, can now operate at even lower temperatures.
Whether taking students on a long route for a field trip or a routine pickup and drop-off route, keeping the air around them as clean and as free of particulate matter as possible and maintaining the emissions-control equipment that does this is becoming even easier. Product offerings such as diesel particulate filters (DPFs) and mufflers get rid of up to 90% of particulate matter with minimal maintenance.
Additionally, engine pre-heaters help school bus operators keep their buses comfortable during cold weather without idling and prolong the life of DPFs by reducing the load on the engine. For example, Paul Baczewski, school bus account manager for Webasto, says, a recent study conducted by an independent emissions testing lab showed that the amount of particulate matter being introduced into a DPF at 70 F can be reduced by almost one-third simply by pre-heating the engine.
SBF spoke with officials from five suppliers of these products to get the latest details on their emission-control offerings.
Clean Diesel Technologies Inc.
Clean Diesel Technologies Inc. (CDTi) now offers the Purifilter™ EGR DPF for school buses, an update of the technology on its Purifilter™ model. Both are EPA-certified and provide California Air Resources Board (CARB)-certified level 3-plus performance, with more than 85% particulate matter reduction, Ian MacDonald, VP of sales and marketing at CDTi, says.
Purifilter™ includes a catalytic coating that oxidizes the gaseous pollutants to carbon dioxide and water, and lowers the ignition temperature of the soot and burns it off during operation. In addition, Purifilter™ EGR also features the coating and augments it with proprietary Mixed Phase Catalyst technology, an upstream diesel oxidation catalyst and thermal insulation, allowing it to operate at significantly lower temperatures than the Purifilter™.
“The Purifilter™ requires 25% of the duty cycle to be over 280 C, while the Purifilter™ EGR can operate at either a condition of 10% above 300 C or 30% over 240 C,” MacDonald says.
Like Purifilter™, the Purifilter™ EGR is also a passive system, meaning minimal operator intervention is needed, even at lower temperatures. The Purifilter™ Plus model features an electrical plug-in that allows operators to only have to clean the filter from time to time, according to MacDonald.
The LNF muffler from Donaldson Co. reduces particulate matter emissions by more than 90%.
Donaldson Co. Inc.
Donaldson’s latest product offerings for school buses include its LNF and LXF mufflers, Todd Lewis, sales manager, says.
The LNF and LXF mufflers reduce particulate matter emissions by more than 90%. The LNF is designed for model year 1993 to 2006 high nitrogen oxide engines, while the LXF is designed for model year 2002 to 2006 low nitrogen oxide engines.
Both muffler kits are equipped with an Emissions Device Monitor that indicates when DPF cleaning is required. The monitor also sends alerts to the vehicle operator through an in-cab display when abnormal or undesirable operating conditions are detected.
The LNF and LXF mufflers are passive systems. The exhaust gas temperature profile for the LNF is: greater than 235 C for at least 40% of the time or greater than 300 C for at least 10% of the time.
The temperature profile for the LXF muffler is: greater than 245 C for at least 40% of the time or greater than 310 C for at least 10% of the time.