“I have never driven a bus that handles as well as this,” he said. “This is a pleasure, for sure.” The EcoCoach features ZF axles all around and uses an independent front suspension setup, which may explain the drivers’ positive responses to the smooth handling and stability. Ian Macpherson, director of product engineering for DesignLine who lead development on the CNG EcoCoach, was on hand to explain the technical aspects.
“The higher roll center of the independent front suspension, along with anti-roll bars at the front and rear, improves cornering at speed,” says Macpherson. The EcoCoach enjoys a 43-foot turning radius, two feet shorter than the length of the bus. Macpherson says for any operator needing something tighter, such as for narrow city streets, the company also offers a ZF steerable tag axle as an option. The reinforced stainless steel chassis and aluminum body frame make for a rigid frame that is also light weight. The custom-designed extrusions bolt together rather than welding which Macpherson says allows for tighter tolerances in their manufacturing process.
Experienced bus and coach drivers are expressing amazement with the CNG fuel economy, which they report to be averaging approximately 30 cents per gallon.
Experienced bus and coach drivers are expressing amazement with the CNG fuel economy, which they report to be averaging approximately 30 cents per gallon.
The 320 HP Cummins ISL-G CNG engine fits into a very open rear compartment designed for easier access and service. “The idea was to keep all the most serviceable components curbside, like the fuel filters, air compressor and air dryer, while keeping as much open space as possible to enable work on the engine,” says Macpherson. The ZF Transmission runs the most upto-date software that includes Automatic Idle Shifting (AIS). When the vehicle comes to a complete stop under certain pre-set conditions, the transmission will actually disengage the driveline to save on engine drag on the transmission torque convertor. The Vehicle Acceleration Control maintains equal performance of the engine and transmission, whether the coach is loaded with passengers or running empty. “This helps with lowering the fuel consumption,” says Macpherson. “With the performance always identical under any circumstance, the coach uses only as much power as it actually needs at the time. In any situation, the performance of the coach will always feel the same to the driver.” The coach features six-wheel antilock brake systems with Bendix/Knorr-Bremse disk brakes all around. Having a common brake setup on each wheel means a reduction in the number of spare parts required, like brake pads. The EMP miniHybrid Thermal Kit mounts above the engine compartment. The fans blow through the front of the highmounted radiator, drawing from both sides and from the top of the bus. “This configuration allows a cleaner airflow,” say Macpherson. “The higher suction points are out of line of the spray from the tires. This keeps the radiator cleaner for longer.” DesignLine says it gave a lot of attention to aesthetics and cosmetics inside and out. “We put a high degree of emphasis on styling this coach,” says DesignLine Director of Sales and Marketing Steven Justice. “Most notable are the enlarged flush mounted windows that evoke a European look. It’s a little different. It expands the view and lends openness to the interior.” BR
Ian Macpherson, director of product engineering for DesignLine, was on hand to explain the technical aspects to David Hyink, Valley Metro’s fleets and facilities supervisor.
BUSRide
January 2013
23