Mercedes-Benz Introduces Natural Gas Econic NGT

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Press Release / August 21, 2014

After receiving a comprehensive upgrade last year which included new diesel engines, suspension, frame, electronics and a revised cab, Mercedes-Benz has now gone one step further with their Econic model.

Available in two purpose-built variants designed for the waste collection and local distribution segments, the Euro-6 Econic NGT features the new M936G natural gas engine. The new six-cylinder in-line powerplant delivers the same performance as a diesel engine while at the same time setting a new benchmark in terms of noise and exhaust emissions.

For Mercedes-Benz, sustainability and resource conservation are key to its corporate philosophy. That's why the Econic NGT (Natural Gas Technology) has been available since 2002.Whether running on fossil-based natural gas or biogas from renewable resources, the Econic exceeds the required emissions standards while ensuring that urban centers remain clean and environmentally friendly.

With its new, state-of-the-art generation of engines, Mercedes-Benz has further developed its natural gas powertrains to comply with Euro-6 standards. The result is the new Econic NGT 1830 and 2630.

The new M936G natural-gas engine in the Econic is based on the 7.7-liter OM936 turbocharged diesel engine. As a mono-fuel engine (gas-powered only), it runs on compressed natural gas (CNG) and has an output of 302 horsepower (222 kW) while delivering maximum torque of 1200 Nm. The single-stage turbocharged engine’s performance is on par with its diesel-powered counterpart, while setting new standards in terms of environmental compatibility, with CO₂ emissions up to 20 percent below those of a diesel engine. Using biogas₂-further improves the carbon footprint.

To a large degree, the new M936G uses the same parts as the OM936 engine on which it is based. The cylinder block and cylinder head are the same, having merely been adapted to run on CNG. Newly developed, on the other hand, are the turbocharger, charge-air ducting, ignition and the entire mixture preparation, including exhaust-gas recirculation. The packaging, however, remains identical, with the natural-gas engine having the same dimensions as its diesel-powered counterpart.

The ignition system in a natural-gas engine is identical to that in a gasoline engine. The M936G uses spark plugs with pencil-type ignition coils. They are housed in the same space that originally accommodated the fuel injectors in the diesel engine. The piston combustion cavity has been given a new geometry for natural-gas operation.

Similarly to a modern-day gasoline engine, the new natural gas engine employs a stoichiometric combustion ratio of lambda = 1. It uses neither excess air, a lean mixture such as in the previous engine, nor a rich mixture. This results in especially clean combustion allied to high power output and low pollutant emissions.

A turbocharger with asymmetrical turbine geometry ensures an excellent response from the engine while at the same time supplying the cooled exhaust gas recirculation, the purpose of which in this case is not to minimize the pollutant emissions, but to lower the exhaust-gas temperature in the interests of durability. For design-inherent reasons, the exhaust-gas temperature in a natural gas engine is higher than in a diesel engine.

The fact that combustion is virtually soot-free obviates the need for a particulate filter of the kind now common on diesel engines with the introduction of Euro-6 (EPA2010). As in a spark-ignition (gasoline) engine, emission control is by means of a three-way catalytic converter.

While meeting the legally required 80 dB(A) limit, the noise level of the new natural gas engine is even lower across the entire engine-speed range than that of the already quiet OM936 diesel engine.

Another advantage of the new natural gas engine is that the extra weight compared with its diesel counterpart has now been halved to just around 500 kg, representing a payload increase of 400 kg over the previous Econic NGT with a wheelbase of 3900 mm. This is due to new gas cylinders in carbon fiber-encased rugged steel specially produced for a lightweight construction.

Stop-and-go traffic plays a major role in the daily operations of Econic users while also placing special demands on both engine and transmission. For this reason, the powertrain in the Econic continues to include the Allison six-speed automatic transmission – there's hardly a more agreeable way to navigate in dense urban traffic. The new Euro-6 Econic NGT features new ECO software, which saves fuel while at the same time increasing the ride comfort.

At the heart of the Econic concept is the ergonomically low-entry and highly spacious cab with its single-step entrance. Wherever driver and front passenger(s) frequently need to leave the cab in the course of their work, this configuration significantly improves their working conditions.

Bearing the design signature of the new generation of Mercedes-Benz trucks, the modern design of the Econic cab is characterized by its new front grille, rugged bumper and standard-fit LED daytime running lamps.

The low-entry cab, which has been successfully retained despite the additional space needed for Euro-6 emissions components, also features a redesigned interior. Driver and passenger(s) in the Econic will appreciate the cab more than ever with its tried-and-tested low entry and exceptional roominess. A totally revised cockpit including a new multifunction steering wheel for quicker access to the instrument cluster, and individually positionable switches, provides drivers with the ideal working environment.

The relocation of the parking brake and transmission controls to the same height as the steering wheel makes them easier to use, safer and more ergonomic. There is added stowage space thanks to lockable stowage compartments above the front-passenger seats as well as cup holders in the central console. Behind the front-passenger seats there is also further space for up to three drinks bottles.

Other highlights of the cab include reconfigured air vents and electrically operated sunblind, which, in combination with more extensive insulation of the cab and engine tunnel, makes for a better working environment inside the cab. Both driver and passenger(s) continue to benefit from a low entry and fully glazed, pneumatically opening folding door on the side away from the traffic.

The Econic NGT is available in 4x2, 6x4 and 6x2/4 configurations with electro-hydraulically and progressively steered tag and pusher axles in permissible gross weight ratings of 18 and 26 tons (39,683lb and 57,320lb).

The two- and three-axle vehicles come in different wheelbases from 3450 mm to 5700 mm. The cab can be ordered in high (1745 mm inside height) and low (1295 mm) variants.

As the Econic offers fundamentally different individual solutions to suit the varying requirements of different operators, new changes to the chassis are of great importance for bodybuilders. For instance, the Econic can be used by local authorities as a waste collection vehicle, by food and drinks delivery firms or by fire services as a vehicle with turntable ladder, or as an auxiliary fire-extinguishing vehicle. In addition, the Econic is now applicable as a tanker or catering vehicle at airports.

Uniform hole patterns in combination with a movable end cross member and rearranged components behind the cab result in improved body-mounting ability while providing extra implement-mounting space. The load capacity of the front axle has also been increased to 8 tons (17,676lb).

In line with the common-parts concept behind the Econic, the engine, chassis and axles are put together from the same set of basic components used in our large trucks, providing customers with significant servicing and maintenance benefits.

The tried-and-tested components of the Econic cab provide class-leading levels of safety. Low and easy entry and exit, air suspension on all axles, large panoramic windsshield with mirror system as well as a fully glazed, electro-pneumatically operated folding door on the side of the vehicle opposite traffic, contribute to the safety of both the crew and other road users while at the same time guaranteeing excellent all-round visibility and minimizing blind spots. Added to this is the vehicle's superb handling owing to a low center of gravity.

Introduced earlier than required by law, a stability control system (ESP) makes the new Econic safer, as does the electro-pneumatic braking system. These two assistance systems now augment the existing anti-lock braking system (ABS) and acceleration skid control (ASR) to play a key role in the Econic's safety concept.

The new Mercedes-Benz Econic 2630 NGT 6x2/4 powered by the new M936G natural gas engine will be on display at the IAA Commercial Truck Show in Hannover, Germany from September 25 thru October 2.

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