GIVING CUSTOMERS WHAT THEY WANTThe objectives of the up! project were to create a car that was good value for money, consumed as little fuel

as possible, was highly practical, and had a level of ride comfort typical of all Volkswagens. To achieve this, a

comprehensive quality assurance process was put in place from the initial phases of the project through to

production release.

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vIRTUAL cUSTOMER ORIENTED vALIDATION

In the up! new technologies for virtually displaying and assessing the characteristics of the whole vehicle were used in the early stages of the car’s development to assess its characteristics and ensure that customer demands were being met. The virtual inte-rior mock-up is one of the key tools the experts use to assess the car from the cus-tomer’s point of view, because thanks to the head-mounted display, for example, it pro-vides the tester with a true-to-life, three-dimensional representation of the vehicle.

Together with Concept Development, we used these new methods to evaluate the first design concepts and make improvements with regard to ergonomics, interior space, and all-round visibility. We also tested the car’s serviceability which enabled us to identify, early on, that the position we had planned to fit the oil filler neck, namely on the exhaust camshaft side, restricted access when trying to re-fill the oil. 1. Using virtual technologies in the early stages of the car’s develop-ment has improved the quality of the development process and cut modification costs dramatically.

SIMULATINg ThERMAL SAfETy MEASURES

To ensure the car operates safely, even under extreme driving conditions – such as driving at high speeds or in mountainous areas – numerical simulation procedures where carried out and measurements taken on the prototype to assess how safe the car was under extreme operating temperatures. These results were then used to implement the necessary measures. Components, for example, in the engine compartment or on

the underbody that are near to the exhaust system must be protected from high temper-atures or must be installed far enough away so as to ensure they do not get damaged.

In the new 1.0 l engine – 44 kW and 55 kW – of the up!, the exhaust system is situated on the bulkhead side of the engine to speed up catalyst heating.

Starting in the early concept phase, we simulated the surface temperatures to find which areas in the engine compartment and underbody were subjected to high thermal loads, 2. After that the components and their shielding were designed, which again were approved by simulation. In a final step, temperature measurements were con-ducted with real vehicles in a climate wind tunnel as well as on different test tracks, in order to affirm and release whole vehicle.

REDUcINg wEIghT

Great care was taken to monitor the weight of the vehicle while it was being developed. This was to ensure that it did not exceed the

target weight specified at the start of the project, a goal set with performance and CO2 emissions in mind. The real challenge in the A00 class was to find efficient solu-tions for the construction of and the materi-als used in lightweight designs. To achieve these goals, we developed innovative inter-disciplinary solutions and identified and implemented new ways of reducing the weight of the vehicle.

Examples of these solutions include the use of lightweight components in the chas-sis (subframe), in the drive train (cylinder block and crankcase), and in the equip-ment (seats). All this means that the up! has an EU curb weight of just 929 kg – which is the best in its class.

fUEL cONSUMpTION

The up! has set new benchmarks for fuel consumption and CO2 emissions in its class. In the standard version of the up! with the 1.0-l 44 kW MPI engine, CO2 emissions are just 105 g/km, 3. This is achieved by

DIpL.-INg. MIchAEL wULff is Technical Group Spokesperson for Whole Vehicle Function and Release

VW120 at Volkswagen AG in Wolfsburg (Germany).

AuThoR

1 Discovery of collision when filling engine oil (left) and realized optimization after collision check (right)

2 Simulating surface temperatures on the underbody during the early concept phase

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: optimising the aerodynamics : a lightweight design : a low curb idle speed : a camshaft phaser to improve the

torque curve at low RPM.These measures allow for an energy-efficient gear ratio and the use of a high economy gear with low RPM, even at high speeds.

The 1.0-l gasoline engines with 44 kW and 55 kW are also available with the environmentally friendly BlueMotion Tech-nology. BlueMotion Technology is based on innovations such as the start-stop sys-tem, regenerative braking, and low-rolling-resistance tires. This means the up! with the 44 kW MPI engine and manual gear-box consumes only 4.2 l/100 km and emits only 97 g of CO

2 per km.Another excellent way to reduce fuel con-

sumption and CO2 is with the eco-friendly CNG engine in combination with BlueMo-tion Technology. This consumes, on aver-age, only 2.9 kg of natural gas per 100 km and emits only 79 g of CO2 per km. In doing so the up! CNG emits 28 g/km less than its only competitor in the A00 class, 4.

AcOUSTIcS

When it comes to the acoustics of a car in the A00 class, it is imperative to find the right balance between cost and weight. This is because the project specifications often do not allow much scope for focus-ing on acoustics during the car’s develop-ment. With the up! we also had the chal-lenge of achieving the optimum acoustic performance for a car in its class.

Offering an engine in two different power classes made achieving this goal that much easier, because the powertrain mount could be optimised for this powertrain. This means the pitch-control mount with rubber-metal elements used in the up! is lighter than those used by the competitors, while still performing very well. It also requires the components to be matched perfectly for idle speed, load change, and acoustics while driving. This is because three-cylinder pow-ertrains naturally exhibit higher levels of vibration displacement.

In addition, during the design phase of the up!, we also made sure that we could use lightweight sound absorption solu-tions. By making sure there was enough space in the bulkhead area, we were able to use low-cost, light stamped-sheet insula-tion to sound-proof the bulkhead, instead

of the usual expensive mold. The precisely tailored structural insulation, combined with the acoustic elements, ensures a rich sound and a well-insulated interior.

Another key objective was to seal the body systematically to reduce the amount of outside noise entering the interior, mini-mising the amount of insulation material needed. We were able to achieve this – from the beginning of the construction phase right up to the start-up phase – by working closely with all the departments involved.

When designing the exhaust system, we also worked on a version for the CNG ver-sion right from the start. By using a main exhaust muffler in the tunnel, we were able to install the gas tank in the underbody sec-tion of the rear end. A conventional exhaust system – consisting of a front and a rear exhaust muffler – would have been far more difficult to incorporate into the car.

The result of all the optimisations is a car that has superior acoustics in its class and lower noise levels than its competitors, ➎.

4 Co2 emissions and Eu curb weights

➎ Interior noise for the VW up! compared with competitors

3 Fuel consumption and performance – projections subject to confirmation from the Type Approval

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