AC Transit’s Commitment to Cleaner Air

News Articles
04/24/2002

AC Transit’s focus on creating a zero-emission bus fleet has not side-tracked its efforts to clean up the exhaust emitted by today’s engines.

AC Transit’s Central Maintenance Facility (CMF), located on 98th Avenue in Oakland, has been in the forefront of these efforts. To date, CMF has retrofitted 40 1993-model coaches with new low-emission engines.

In addition to cleaner exhaust, the state-of-the art engines also provide better fuel mileage and better mechanical durability. Plans are to repower the remaining 2800s in the fleet. The Gillig Corporation in Hayward, California manufactured the 2800 series in the first quarter of 1993.

Equally important are ongoing programs that keep engines in top working condition. Routine inspections, performed every 3,000 miles, help to ensure optimal engine performance. Also, Maintenance performs exhaust opacity tests on all buses twice yearly, which exceeds the requirements of state law. Out of 6,800 opacity tests run since mid-1999, only 49 “failures” were recorded, and those engines were quickly repaired.

This year, AC Transit switched to cleaner-burning ultra low sulfur diesel fuel, which will be mandated by the state of California in July. This reduced-sulfur fuel helps in cutting down on tailpipe emissions.

A major campaign is being prepared to retrofit exhaust filters to trap particulate matter in engine exhaust on 378 coaches. Industry experts say this fully funded project should achieve a major reduction in emission of the microscopic soot-like particles that now cloud engine exhaust.

The District last month sent coach #3010 to Cummins West’s San Leandro plant for installation of a test exhaust gas recirculation (EGR) unit. Similar to automotive EGR systems, this unit is designed to cut nitrogen oxide (NOx) emissions—a contributor to smog. In addition to substantially reducing the NOx gases, the test installation will include an after-treatment trap to reduce particulates.