Euro VI is coming - Mercedes-Benz is already there: at the FIAA show in Madrid from 23 – 26 October 2012 the brand will be presenting a new generation of bus chassis designed to comply with the future Euro VI emissions standard. The OC 500 LE chassis for regular service buses and OC 500 RF chassis for touring coaches are made in Spain, where Mercedes-Benz is the sole manufacturer of bus chassis.
New engines: clean, fuel-efficient, durable, powerful
The core of the new chassis generation is the newly developed powertrain for the Euro VI emissions standard. The chassis centre around a totally new generation of engines forming part of the BlueEfficiency Power concept. The engines already comply with the Euro VI emissions standard in all power ratings. Common features include the basic technical configuration with common rail injection and emission control using SCR technology with AdBlue injection, as well as an oxidation catalytic converter connected in series and a particulate filter.
All the engines combine impressive performance with lively acceleration right from the low rev range and extremely smooth running with low fuel, AdBlue and engine oil consumption while displaying exemplary environmental credentials. Despite the engines' compliance with Euro VI, fuel consumption is generally below that of the predecessor engines. A further notable feature is the long intervals of up to 120,000 km for engine oil changes in touring use.
The new Mercedes-Benz OM 936 six-cylinder in-line engine is particularly compact and light. It comes in two variants generating 220 kW (299 hp) and 260 kW (354 hp) from a displacement of 7.7 l. This engine is to be deployed both in the low-entry Mercedes-Benz OC 500 LE chassis and the two-axle touring coach chassis of the OC 500 RF series.
The equally new OM 470 six-cylinder in-line engine with a displacement of 10.7 litres belongs to the heavy-duty class. Tailor-made for use in the touring coach chassis of the OC 500 RF series, it is available in two power ratings – 290 kW (394 hp) and 315 kW (428 hp).
The positioning of the engines corresponds to that in the fully equipped buses from Mercedes-Benz with high-floor rear-end: as a general rule the exhaust system is now installed on the left side, the cooling on the right. The radiator unit is separated from the engine by a bulkhead and is also encapsulated on top.
Manual, fully automated and automatic transmissions
The engine power on the OC 500 RF is transmitted as standard via manual six-speed transmissions from Mercedes-Benz. A new development is the Mercedes-Benz GO 250-8 PowerShift fully automated eight-speed bus transmission. This progressive transmission now offers even faster and more comfortable gear shifting. The shift mechanism is completely new: all functions are conveniently and compactly incorporated in a steering column switch.
The OC 500 LE regular service bus chassis from Mercedes-Benz comes with the ZF EcoLife automatic transmission with torque converter. This transmission is equally ideal for urban and rural regular-service buses and is also suitable for buses based on the OC 500 RF.
A new retarder is employed in conjunction with all manual transmissions. It uses the engine cooling water as a braking and cooling medium. The previously necessary oil/water heat exchanger is no longer required. The new design results in a weight reduction of around 30 kg, accompanied by an increase in continuous braking power.
Defining features of the modified Mercedes-Benz RO 440 drive axle are low weight, low friction, quiet running, further improved suspension and enhanced ride comfort. The load-carrying capacity has risen to over 12 tons.
High-tech to cut added Euro VI weight
The new rear axle is one of numerous components by means of which the developers have managed to largely offset the unavoidable increase in weight relating to compliance with Euro VI. Other measures concern high-strength steels for the frame, the lighter retarder, lighter yet higher-capacity alternators and the new encapsulation under the engine.
Proven and popular worldwide: chassis from Sámano
EvoBus Ibérica produces buses for all types of use in Sámano/Spain. Its customers include Spanish coach builders and markets throughout the world. The chassis are produced in buggy design with a transport frame and undergo cathodic dip priming to ensure optimum anti-corrosion protection.
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