fastfivecars TRIVIA: Safety research test lab on wheels

OFFICIAL PRESS RELEASE

Stuttgart, Germany, May 04, 2004

- June 1974: Presentation of the ESV 24 Experimental Safety Vehicle
- Numerous equipment features incorporated in present-day production models
- ESV 24 marks the end of Mercedes-Benz's ESV program


Safety research has always been writ large at Mercedes-Benz. A major contribution to safety was rendered by the ESV 24 which continued the tradition of earlier Experimental Safety Vehicles. It was based on the production version of the S-Class (W 116) with all its protective features but with a specially modified front end to permit the investigation of design solutions for a frontal impact at 65 km/h against a rigid barrier. At Mercedes-Benz, the ESV 24 marked the end of the international ESV (Experimental Safety Vehicle) research program, "because an optimum compromise between the original ESV specifications and our present-day production cars has been reached with this vehicle," it said in a development report written in 1975. The ESV program had been initiated by the US Department of Transportation in 1970 and requested motor manufacturers to build safety vehicles which met extreme demands on active and passive safety.

Within the framework of this program, Mercedes-Benz developed a large number of equipment features which were integrated in production models at a later stage. These included:

- Head restraints for all occupants
- Three-point inertia-reel seat belts
- Belt tensioners
- A particularly rigid passenger cell with optimized front-end, rear-end and side structures
- Safety steering

From the ESV 24 the following features were adopted:

- Belt force limiters
- Airbags
- Belt anchorage integrated in the seats

Prior to the ESV 24, the ESV 05 (1971) and the ESV 13 (1972) had been presented to the public. Both corresponded to the ESV specifications of the US Department of Transportation and in particular met the demands on occupant protection in a frontal crash at 80 km/h. However, these cars were some 50 percent heavier that the basic Mercedes-Benz 250 (W 114), with adverse effects on fuel consumption and emissions. This was one of the reasons why Mercedes-Benz compiled its own specifications book and concentrated on researching occupant protection at the impact speeds considered to be relevant, i.e. between 80 and 50 km/h, using a European design of the three-point seat belt. The ESV 22 presented in 1973 provided protection at an impact speed of 65 km/h but was still some 20 percent heavier than the basic car from the Mercedes-Benz S-Class (W 116).

The ESV 24 based on the same model finally had an unladen weight of 1,940 kilograms, just ten percent more than the production version, and was thus clearly closer to production standards. The permissible gross weight was 2,340 kilograms. The fully operational car was powered by a V8 engine with a displacement of 4.5 liters and an output of 165 kW (225 hp); its emission control system corresponded to the US specifications for model year 1974.

When Daimler-Benz decided in 1971 to participate in the ESV program, the company had already been engaged in safety research for years and was determined not to lose its leading position ahead of other motor manufacturers. As many as 31 ESV were built, all of them based on production models. They were used for research activities and their end was predetermined: they were destined for destruction in crash tests. Only five vehicles were shown to the public.


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