Even Scania switches to the parallel hybrid drive system. There is an eco-sustainable solution based on the Citywide LE model with the engine running on biodiesel

THE SCANIA PARALLELHYBRID

Since 30 years the Scania designers have been trying their hand at hybrid drives.

The construction of the first Scania hybrid bus prototype dates back to the mid 80s. In recent times, on the international markets the-re has been a rising tide of interest for this drive system that we saw at the UITP 2007 in Helsinki where Scania also presented its Concept bus with hybrid-series technology (motogenerator diesel plus supercapacitors and electric traction motor). Many have con-sidered this system as the most suitable one for city buses.But the market has its own laws and at the UITP 2013 in Geneva, Scania took note sta-ting that the energy storage systems (batte-ries and supercapacitors) have not evolved enough to provide a commercially satisfac-tory solution when it comes to service life and lifecycle cost. Hence the development of

Length mm 12,000 Width mm 2,550 Height mm 3,360 Seats 33+1H+1 (3 doors) Seats 37+1H+1 (2 doors) Diesel engine Scania DC09 108 Displacement cc 9,290 Power kW/cv 235/320 at 1,900 rpm Torque Nm/rpm 1,600/1,050-1,300 Gearbox Scania E-GRS895 Electric machine 150 kW/1,050 Nm Battery pack lithium-ion Voltage 650 V Usable energy 1.2 kWh Inverter 150 kW DC/DC converter 7.5 kW

SCANIA CITYWIDE LE 12 HYBRID

BusToCoach on-line Magazine - September 2015

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1 Energy storage.2 DC/DC converter.3 Junction box.4 Coolin system for energy storage.5 Coolin system for inverter and DC/DC converter.6 Battery heater. 7 Scania Opticruise with electric machine. 8 Inverter. 9 DC link. 10 Coolant circuit for the inverter. 11 Cooler for gearbox oil. 12 Diesel engine Scania DC09 320 hp.

a parallel-hybrid system (diesel engine plus online electric motor and battery pack) pre-sented at the IAA 2014 in Hanover. The 12-metre low-entry Citywide model (and the 3-axle version of 14.8 metres) has a drive system comprising the Scania Euro VI 9-litre diesel engine in 320 hp. The engine is coupled to the 12-speed automatic gearbox Opticruise integrated with a synchronous electric machi-ne with permanent magnet of 150 kW.The 1.2 kWh energy storage is provided by a lithium-ion battery integrated in the roof structure at the front of the vehicle, housed together with DC / DC voltage converter from 650 to 24 volt (power of 7.5 kW) that replaces the traditional alternator, the heater for batteries and cooling systems for batteries, converter and inverter with a capacity of 150 kW, that is positioned in its turn at the engine compartment.

Using the Citywide LE hybrid, Scania de-clares that you can face the city and suburban traffic with the same performance, being able to easily reach speeds up to 100km / h. And as for consumption, the use of the Scania hybrid system together with a DC/DC converter, stop-start function and Hybrid Eco-roll, provides savings between 20 and 25%, or between 1, 2 and 2.5 litres per hour of operation.If we use 100% biodiesel (possibility offered by the 320 hp engine), CO2 emissions are re-duced by 65%.The Scania Citywide hybrid is working quie-tly especially at low speeds when functioning only with the help of electrical system. When the vehicle is running with low torque, hybrid

eco-roll is activated. The electric machine then takes care both of pulling away and braking, thus keeping to a mi-nimum the engine wear. Finally, the engine stress is also reduced by stopping it at bus stops when a door is open or when the gear-box is in neutral and the parking brake is ap-

plied.The Citywide LE Hybrid is also

equipped with the Scania Commu-nicator, which is the link to the Scania

Fleet Management for the collection, analy-sis and transmission of data. The vehicle and the driver data can then be fully monitored remotely via an interface. Driver assistance is provided by Scania Driver Support which continuously informs the driver on the driving style.In the three-door configuration with two double and a single-leaf door on the rear overhang, the 12-metre Citywide hybrid can accommodate 33 seats. The floor has been lowered to 350 mm of the ground till the se-cond door and two steps give access to the corridor in the raised rear part.The Citywide hybrid alongside with the who-le range is built at the Scania plant of Slupsk, Poland, with underfloor structure made in steel and body in extruded aluminum profi-les bolted and covered with aluminum rive-ted and bonded panels. The same material is also used for the two heads, in addition to the polyurethane and polyester shockproof panels. •

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