Automotive Intelligence - the web for automotive professionals and car enthusiasts
December 06, 2011
Off-road figures like an SUV. Away from made-up roads the Cross Coupé makes its mark with bodywork figures that fall almost into the range of classic SUVs. The front angle of approach, for example, is a good 24.2 degrees and the rear in terms of off-road use an excellent 32.5 degrees. The Cross Coupé also features good off-road ground clearance.
Electrically powered rear axle
Three motors in one car. The Cross Coupé has not one but three motors, which work together efficiently as a hybrid system. At the front under the bonnet is a 110 kW TSI petrol engine delivering maximum torque of 210 Nm and an electric motor with an output of 40 kW and 180 Nm of torque. Together or individually these two motors power the front axle. If the Cross Coupé is to be used in all-wheel drive or pure electric power mode, a further electric motor cuts in. This has been integrated as a co-axial drive unit into the rear axle layout. This motor drives the rear wheels. This second electric motor generates up to 85 kW and develops torque of 270 Nm. The overall output of the system (petrol engine + battery) is a maximum of 195 kW.
Tunnel battery powerhouse. When the vehicle is being driven purely on electric power, the electric motors receive their current from an 8-module lithium ion battery. The battery holds 9.8 kWh of energy and is located inside the Cross Coupé’s centre tunnel, i.e. where the drive shaft is found in conventional SUVs. An electronic power control module, operating at around 370 volts and integrated into the engine compartment, manages the flow of high-voltage energy from and to the battery and to the electric motors. Meanwhile, the Cross Coupé’s low voltage electrical system is supplied with the necessary 12 volts through a DC/DC converter. The electric drive system causes no space restrictions in the vehicle’s interior. The battery gets charged either via external electricity sources (230-volt connection) or – in motion – via the TSI engine and battery regeneration (both front and rear axles).
Fuel consumption of just 2.7 litres per 100 km. With a full tank of fuel the Cross Coupé weighs 1,748 kg (58% on the front axle, 42% on the rear). It can take a further load of 450 kg and be driven a distance of up to 45 km on purely electric power. In doing so the vehicle produces no emissions. In the New European Driving Cycle (NEDC) the TSI engine’s fuel consumption is just 2.7 litres per 100 km, equating to CO2 emissions of only 62 g/km. With a fuel tank capacity of 55 litres, the theoretical range in hybrid mode is 815 kilometres. Adding in the electric range, the Cross Coupé can do 855 km without stopping for fuel.
Sustainable and yet still dynamic. Despite the focus on sustainability the concept car being shown in Tokyo is still sporty. The Cross Coupé accelerates from 0 to 100 km/h in just 7 seconds and has a top speed of 201 km/h. If forward propulsion is being provided solely by the electric motors, the top speed is regulated down to 120 km/h. Both the consumption figures and driving performance are positively influenced by the Cross Coupé’s aerodynamic properties. The optimally balanced aerodynamics built into the design and the very low overall height (for an SUV) produce a very good drag coefficient of 0.329.
How the hybrid drive system works. Both electric motors help (boost) the petrol engine (TSI) during acceleration. As mentioned above, however, they can also power the concept car on its own for a distance of up to 45 kilometres, depending on conditions. Here, by opening the clutch, the TSI gets disconnected from the drive-train and switched off. The clutch on the gearbox side, however, remains closed and the seven-speed DSG thus remains connected. Cross Coupé drivers can themselves also choose to drive relatively long distances on pure electric power (as long as the battery has enough charge). To do so the driver simply presses the relevant driving mode button on the centre console next to the gear lever. As soon as the TSI needs to be brought back into play due to the battery’s level of charge or any other parameters, the engine starts up – almost imperceptibly for driver and passengers – and smoothly engages with the drive train.
Charging at the press of a button. Whenever the Cross Coupé’s brakes are applied, both electric motors act as a generator, utilising the braking energy to charge the battery (battery regeneration). The driver can (via another button next to the gear lever) also consciously charge the battery from the TSI engine – for instance, in order to have sufficient electric power to drive later in a regulated zone preserved exclusively for zero-emission electric vehicles. At all times, the current electric range and the Cross Coupé’s overall range are displayed on the instrument panel. The engine controller regulates all energy flow and drive management tasks taking into account the minute-by-minute demands for power made by the driver.
‘Electric power’, ‘Charge’ and three further modes. Based on the amount of drive (for instance, loss of traction on the front axle) or through the driver consciously switching to all-wheel or electric mode, the second electric motor integrated with the rear axle engages it in an instant. In general there are three driving modes available to the driver: City (eco-mode with minimal fuel consumption), Sport (dynamic driving) and Offroad (permanent all-wheel drive).
(30 November 2011)