Page 1 of 2
[IMAGE]Daimler.jpg[/IMAGE]In early February, Daimler Buses North America (DBNA) held a transit clinic at its Mississauga, Ontario, plant to give customers a sneak peak at its revamped transit offering — the EPA 2010-compliant Orion VII model. In addition to being equipped with a propulsion system that adheres to the Environmental Protection Agency (EPA) emission standards, the new vehicle is also a showcase for new customer options such as BRT roof styling, a 1:6 slope ramp and floor hatches. Other innovations that aren't as visible include the standardization of various components and the simplification of processes across the hybrid, diesel and CNG models.
"The first goal was to reach EPA 2010, as well as reach a new level of quality," says Danijel Miklaucic, project EPA2010 manager, of the undertaking.
EPA 2010 changes
To be compliant with the EPA emission standards, the company employed SCR (selective catalytic reduction) technology, which required some adjustments to the vehicle frame, said Ian Moger, senior engineer manager for DBNA. The SCR technology needed to occupy the space of the rear air- conditioning unit, which led to the use of a roof-mounted air conditioning unit. The CNG model still uses the rear engine compartment to house the air- conditioning unit.
The hybrid product is equipped with a Cummins ISB 280 Diesel engine; the diesel bus is equipped with Cummins ISL 280 Diesel; and the CNG model features the Cummins ISL-G 280 CNG engine. The company integrated the latest in transmissions for the vehicle as well to further improve fuel economy performance. A new T-Drive Hybrid arrangement was also developed with BAE Systems.
"We looked for optimizations of standardizations in the area of the cooling system, battery tray, driver's barrier and bridge panel," Moger says. "We eliminated the engine cradle with the EPA2010 design and we've made improvements to the front and rear suspensions."
Other design standardizations included the mounting brackets for pipes and harnesses. "We've reduced the number of studs on the vehicle as well as reduced the number of ways we attached harnesses from 20 to about eight," Moger says.
In addition, more customer options were added to the new EPA2010 Orion VII, including BRT roof styling, disc brakes, a ramp with 1:6 slope and floor hatches that provide easy access to such areas as connections on transmissions.
"Bad road" testing
Once the prototypes were completed, DBNA conducted structural durability testing on the vehicles. This program, also know as the "bad road" test, was an all-new testing process for the new EPA 2010 compliant Orion VII transit bus. Daimler's testing program is comprised of the following tests: Altoona, endurance, functional, all-season road testing and the bad road test. The structural durability testing evaluates the lifetime of the bus in a compressed timeframe, allows for three-dimensional testing for the frame and includes all driving maneuvers (steering, braking, etc.). It takes up to one year to complete, while the previous testing method includes the use of the "shaker" test, which lasts three months and simulates vertical forces in a controlled, indoor environment.
The Daimler Durability Testing program is conducted at the Bosch Proving Ground in New Carlisle, Ind. During the 12-month test period, the buses are driven 24 hours a day over a track, which includes numerous "bad road" conditions such as impact bumps, staggered bumps, resonance road and light cobblestones as well as the Altoona upper/lower track." Our goal is to simulate the service life of our customers," says Oliver Kurz, manager of testing and prototyping.
Following 2,400 laps on the Bad Road Proving Ground, the EPA 2010 Orion VII will have completed a simulation of driving conditions representative of over 500,000 transit service miles in North America's most severe operating environment. Vehicle engineers are able to assess the long-term structural durability; steering and drive train effects; wear and tear of brakes; and wear and tear of the engine and other components based on this testing process." It takes one year to complete this testing versus three months with the shaker test," says Kurz. "And the benefits are far superior."