Daimler engines as Wrightbus targets Euro growth

Streetlite

A development of the Streetlite EV is a new version equipped with Induction Power Transfer (IPT). The first examples have been delivered to Milton Keynes

At Euro6, apart from the StreetDeck and the NBfL double deckers, WrightBus will be offering the Streetlite single decker as part of its complete integral range in both door forward and wheel forward configurations.

Engine options will be either the Cummins ISB4.5L delivering 160hp (120kW), 180hp (134kW) or 210hp (157kW) and, as in the StreetDeck, the Mercedes-Benz OM934, though for the Streetlite this is rated at either 180hp (130kW) or 207hp (155kW).

Gearbox options are the Voith DIWA 824.6 four-speed automatic or the Mercedes-Benz automated manual AM-T unit which has been specially designed to operate with the OM934 engine and with which it shares a single ECU system. Designed to cope with torque of 1,100Nm, we were told that the latest version changes more quickly, incorporates a creep function and delivers a 6-10% fuel saving over the Voith.

In First Group’s V3 comparative fuel test cycle, an 11.5m Streetlite Max achieved 10.2mpg which was 17.2% better than an undisclosed medium weight vehicle returning 8.7mpg and 37.8% better than an undisclosed heavyweight bus which returned 7.4mpg.

Micro Hybrid

A Streetlite Max for First equipped with the cost effective new Micro Hybrid package

Developed at Euro5 and now carried over for Euro6 across the Streetlite range is Wright’s Micro Hybrid technology. This recovers braking energy, stores it and uses it to power the vehicle’s ancillary pneumatic, electrical and hydraulic systems so that the engine does not need to reducing overall fuel usage. Control software systems consider the system charge state and the workload and if parts of a route don’t generate sufficient energy recovery the system reverts to demand based charging. It uses the vehicle’s standard batteries and compressed air tanks to store the energy, ensuring the concept can offer savings without the cost or weight disadvantage of a full hybrid. For between £6-9,000 per bus, it gives an overall fuel saving of 9.2%.

Streetlites fitted with the Micro Hybrid system will qualify for Low Carbon Emission Bus (LCEB) certification, enabling operators to claim an additional fuel subsidy of 6-pence per km in England and 14-pence per km in Scotland under current legislation.

Brian Maybin commented, ‘In the LCEB testing programme, a 11.5m Streetlite Max fitted with Micro Hybrid technology shaved a further 10% off fuel consumption. This was on top of the class-leading fuel efficiency figures already delivered by the conventional Streetlite. With exceptionally low CO2 emissions (711 gms per km tank to wheel), this equates to a potential environmental saving of 155 tonnes over 15 years compared to its nearest rival. This is all from a vehicle that has passenger capacity of 70, with 45 seated.’

The first generation of the system is also to be incorporated in the StreetDeck product. An upgraded second generation is also under development and is expected to be available in the Streetlite in early 2015.