A New Innovative Automobile Concept in the Compact Car Class

Within the vehicle concept the sills are relatively high,with the result that the position of the seats in a sideimpact collision is above the area most commonlyaffected by intrusion, providing a very high standard ofsafety. The strong door impact members, in conjunctionwith the B-post taking the form of a large-size ribbedcasting and side airbags fitted as standard, reduce theload on the car's occupants. The structure with a roofframe designed for maximum rigidity in addition affordsvery good protection in a rollover.The Audi Space Frame is likewise beneficial in a rear-endcrash. The sturdy structure formed by the longitudinaland cross-members at floor level permits effective energyabsorption and braces the impact forces in a forwarddirection. Energy is absorbed in a highly effective mannerthanks to the folding-dent behaviour of the extrudedsections of the rear longitudinal members. The casting infront of these is designed such that it sustains minimumdeformation, to keep the fuel tank protected. Thedeformation of specifically only the rear section meansthat the passenger cell protects the occupants veryeffectively in a rear-end collision, too.AERODYNAMICSAudi’s new aero-acoustic wind tunnel was used for theaerodynamic testing of this model. With the road surfacemoving at the wind speed being simulated, and thanks tothe rotation of the vehicle wheels, the boundaryconditions that prevail in reality can also be simulated, sothat realistic measurements are obtained.The good aerodynamic performance has been achievedby defining the vehicle's fundamental characteristics at anearly stage:The range of engines, Table 1, currently includes a 1.4 lspark-ignition engine and two Diesel engines withdisplacements of 1.2 l and 1.4 l. These engines are sharedwith other cars built by the VW Group, and have beenadopted on the A2 with slight modifications.1.4L 55 KW SPARK-IGNITION ENGINEThe 1.4 l engine has an output of 55 kW at 5000 rpm anddevelops a torque of 126 Nm at 3800 rpm.This engine, designed for low weight and fuelconsumption, has an aluminium diecast crankcase withcast-in grey cast iron liners. The engine is fitted with ashell-type plastic intake manifold and an exhaust systemmade entirely from stainless steel.The two camshafts, which each operate two valves viafrictionally-optimized timing gear with roller cam follower,are mounted in the two-piece cylinder head. The enginecharge cycle has been designed for an ample torquecharacteristic.The frictionally optimized engine is an ideal basis for lowfuel consumption. The A2 1.4 l recorded fuelconsumption of 6.0 l/100 km over the MVEG II cycle.The low fuel consumption is partly attributable to the lowidle speed of 680 min -1 . CO2 emissions are only 144g/km. The EU 4 emission standard is fulfilled in particularthanks to the inclusion of a primary catalytic converter inthe front pipe.• Short rounded front structure• Flat, inclined windscreen that flows continuously intothe arched roof• Relatively high, aerodynamically effective fastback• Optimized exterior rear mirrorsThe aerodynamic fine-tuning, such as the measures to theunderbody, has produced low c D values. A dragcoefficient of c D = 0.28 has been measured for the basicversions with the two 1.4 litre engines, and of c D = 0.25for the 1.2 l TDI.The aerodynamic drag, which is proportionally c D * A, isrelatively low, particularly on the A2 1.2 l TDI, at 0.544.Unlike other vehicle concepts, Fig 7, the A2's lowaerodynamic drag is achieved by reducing the dragcoefficient, and not the cross-sectional area. Theergonomics of the A2 are consequently much better thanfor comparison vehicles.ENGINES AND PERFORMANCEFig. 7: Cross-sectional area and c D value comparison.1.4 l 55 kW DIESEL ENGINEThe following features are making the 1.4l 55 kW TDIDiesel engine particularly suitable for use on the A2:• Inline 3-cylinder engine as a spacesaving, weightoptimizedpower unit for transverse installation,4