World Record for Mercedes E 320 CDI: In Detail

Press Release

From production line to world-record circuit

 

Record-breaking Mercedes-Benz E 320 CDI is a production model

 

The three Mercedes-Benz E 320 CDI models involved in the world-record run in Laredo, Texas, set out to prove that perfectly standard products from Mercedes-Benz are outstandingly durable, even when subjected to the most extreme stresses. The fact that no fewer than three vehicles set out to set a record was for a simple reason: it proved the reliability of today's E-Class three times over. Areas of special interest were the powertrain with the newly developed V6 diesel engine and 7G-TRONIC automatic transmission as well as peripheral assemblies such as the fuel system, engine management system and, in particular, the entire exhaust system with its diesel particulate filter. The only modifications to the record vehicles involved the installation of an interior roll-over bar. In addition, coloured plastic sheeting was affixed to each car, and the fog lamps and exterior mirrors were coloured for easy identification.

 

Before the record run could start, Mercedes-Benz had to satisfy a number of conditions imposed by the FIA. The first of these involved compliance with the Category B, Group 3, Class 11 classification of the vehicles. This means that that the record bid had to be conducted using standard-production vehicles powered by a turbodiesel engine with a maximum displacement of 3 litres. Furthermore, an accurate list indicating the records which were being targeted had to be prepared. A total of 22 international FIA records were specified, ranging from the 10-kilometre short distance to the final long-distance targets of 100,000 kilometres and 100,000 miles (160.934 kilometres). In accordance with the vehicle classification, an official from the DMSB (Deutscher Motorsport-Bund), the German body representing the FIA, chose nine new E 320 CDI models from a random group of vehicles on the assembly line in Sindelfingen; tamper-proof seals were applied to these vehicles. The nine cars were allowed to be run-in briefly by Mercedes-Benz employees under the supervision of the FIA official. Three vehicle were then selected from the group of nine, fitted with a roll-over bar and marked in different colours. They were then tamper-sealed once again before being transported to Laredo. Here, too, they were under the constant supervision of FIA* officials.     

 

Strict rules for world-record bid

 

Stewards and Technical Observers from the USAC (United States Auto Club) are also on hand to monitor events at the Texan test track throughout the 30 days of the record bid. They report to the ACCUS (Automobile Competition Committee for the United States), which in turn represents the FIA* as a local national body. Strict limits are set for the scope of repairs during the run: the replacement of entire assemblies such as the engine or transmission is prohibited. And limitations also apply to any repairs over and above the usual servicing activities or the replacement of lubricants and wearing parts. Before the start of the record attempt, the Mercedes engineers had to specify replacement parts which are kept in an FIA*-sealed container next to the track. The vehicles participating in the record bid have to carry a weight equivalent to that of these replacement parts, limited to 5% of the vehicle weight plus 20 kg, at all times. And, of course, the record clock keeps running during refuelling stops, servicing and any repairs which may be necessary. As a further hurdle during record-breaking bids with standard-production vehicles, additional measuring or transmitting systems such as telemetry are not permitted. Only the standard diagnostic software which can be found in Mercedes-Benz workshops may be used.

 

* The Paris-based FIA (Fédération Internationale de l´automobile) is acknowledged as the

   governing body for world-record attempts in the automotive sector

 

 

E 320 CDI: Overview of technical data

 

 

Laredo – the venue for the world record

 

Torture in a good cause

 

The surroundings look more like the setting for a remake of a classic western than the venue for an automotive world record. The Auto Testing Properties Laredo (ATP Laredo for short) proving ground is situated in the middle of the Texan prairie, not far from the border city of Laredo on the Rio Grande. At first glance, the test site would seem to offer optimum conditions for conducting a world-record bid with average speeds in excess of 200 km/h. And with an annual count of 320 days of sunshine and an average temperature of 23.5 degrees Celsius, the climatic conditions also seem ideal. 

 

Heat, dust and a bumpy circuit

 

But a closer examination soon reveals that the ATP Laredo facility is subject to a number of factors which are more likely to be detrimental to the vehicles and engines involved in a world-record bid. Daytime temperatures in March are already over 30 degrees Celsius while the nights are decidedly chilly. Whenever the wind picks up it drives a large amount of dust into the air, thereby putting particular demands on the filter systems for the engine and passenger compartment which, like every other aspect of the vehicles, have to demonstrate their effectiveness throughout the 30-day record run. The repertoire of this somewhat uneven circuit also includes potholes, cracks and bumps which ensure that the vehicles will be subject to continuous shaking and vibration over the entire record distance. The five-mile circuit with its slightly banked curves does not even out lateral forces, so the drivers constantly have to make steering corrections. The lateral forces acting on the car all the time mean that the steering system and front suspension are subject to severe stresses and strains.

 

A link in the worldwide network of DaimlerChrysler test facilities

 

Covering an area of some 810 hectares, the ATP Laredo facility is one of the larger test sites in the worldwide network of test sites owned by DaimlerChrysler. In addition to its high-speed circuit, the facility features a two-mile (3.22 km) oval and a very wide range of torture tracks such as undulating block sections, coarse cobbled roads, mud tracks, potholed tracks, splash troughs, off-road sections and steep grades. A handling section and various circular surfaces for driving dynamics testing complete the list of test facilities.

 

Set up in 1963 by United States Rubber Company, the facility was taken over by tyre manufacturer Michelin in 1990 before it went on to be integrated in the worldwide DaimlerChrysler network as ATP Laredo in 1998. Some six million dollars have been invested in the modernisation of the site since it was taken over.  

 

New V6 diesel engine from Mercedes-Benz

 

Agility and driving pleasure as standard

 

The concept of diesel driving pleasure achieves a new quality with the new CDI engine. As the successor to the five and six-cylinder in-line engines it offers an increase in output and torque of up to 38 percent, ensuring faster acceleration, brisk intermediate sprints and a higher top speed. The maximum torque of 510 Newton metres is already available from 1600 rpm, and remains constant up to 2800 rpm. Accordingly the new V6 has torque characteristics which are unsurpassed in this displacement class. In combination with the unique 7G-TRONIC seven-speed automatic transmission, this ensures the best possible exploitation of the remarkable output and torque potential in any driving situation.

 

Despite a significantly higher output, the fuel consumption remains at the exemplary level of the previous five and six-cylinder diesel engines.

 

The choice of materials, design, fuel injection and engine management system reflect the state of the art. As a world first for a diesel engine in this displacement and output class, Mercedes-Benz has developed an aluminium crankcase with cast-in grey iron cylinder liners for this unit which makes a major contribution to weight reduction. As a result, the new V6 weighs a total of only approx. 208 kilograms (acc. to DIN) and is therefore only very slightly heavier than the previous five-cylinder engine. The power-to-weight ratio has increased by more than 20 percent to 0.79 kW/kg – a major contribution to the outstanding diesel agility offered by the new engine. The engine block, components and ancillary units form a very compact entity, which means that in future the new V6 will also be installed in Mercedes model series and 4MATIC variants where no six-cylinder diesel engine was previously offered.

 

Fuel injection at 1600 bar and innovative piezo injectors

 

Mercedes engineers have refined the common-rail direct injection system, achieving further progress in fuel consumption, exhaust emissions and combustion noise with this third-generation technology. Newly developed piezo injectors work much faster and more precisely than the previous solenoid valves and ensure the fuel supply to the cylinders is very accurately metered. This allows the fuel injection to be even more precisely adjusted to the current load and engine speed, and now makes five injections per power stroke possible at a peak pressure of up to 1600 bar.