Mercedes Citaro NGT - another IAA debut

© Daimler BusesClean, green and not at all mean - the new Citaro NGT city bus

To be quite frank, the new Citaro NGT (Natural Gas Technology) was not a world premiere – it was first presented at the Busworld fair in Kortrijk, Belgium, in 2015. However, this was the first time the bus was displayed on the show floor of the IAA in Hanover.

The latest incarnation of the methane-powered Citaro comes in 12- (solo) and 18-metre (articulated) versions. Their passenger capacities are, respectively, 96 and 153 people. The engine offers high output, low fuel consumption (thus also low CO₂ emissions), low noise emissions and long maintenance intervals.

The natural gas engine is a compact unit with a displacement of 7,7 l. It's operating characteristics resemble those of a diesel equivalent, while obviously nitrous oxides and particulate matter emissions are virtually eradicated and noise levels are significantly lower. The turbocharged motor bears the designation M 936 G and is based on the modern and advanced OM 936 diesel unit.

© Daimler BusesThe CNG tanks are made of composite materials and mounted on the roof

The engine generates 222 kW (302 PS) of power and a whopping 1200 Nm of torque between 1200 and 1600 rpm. Despite providing such impressive performance figures, the unit produces emissions well below Euro 6 required levels. Both fossil natural gas and renewable biomethane can be used as fuel. In the latter case, the bus is practically neutral in terms of carbon dioxide emissions.

From the engine, power is transmitted to the rear wheels via an automatic gearbox featuring a torque converter. The roof-mounted CNG tanks feature composite liners reinforced with carbon and glass fibre soaked in resin. This technology provides extra sturdiness and safety (no risk of corrosion), all the while maintaining relatively low weight (the entire tank battery weighs in at 485 kg) and greater capacity. This means the number of vessels has been recuded by one (compared to the previous-generation Citaro NGT), but the capacity remained unchanged.