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Mercedes for the kids |
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Cedy´s world
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May 1995: ESP makes its debut
in the Mercedes-Benz S 600 coupe
Milestone in safety engineering
Risk of skidding significantly reduced in all situations
ESP is today standard equipment on all Mercedes-Benz passenger
cars
Ten years ago, a milestone in safety engineering was
incorporated in the large-scale production of the Mercedes-Benz
S 600 coupe: the Electronic Stability Program, ESP. ESP reduces
the risk of skidding during cornering and keeps the car on
course even under extremely difficult conditions such as black
ice or wet roads. The system today forms part of the standard
equipment of all Mercedes-Benz passenger cars.
“If all cars were equipped with the Stability Program, more than
20,000 serious traffic accidents with over 27,000 accident
victims could be prevented in Germany every year,” says Dr.
Thomas Weber, member of the DaimlerChrysler Board of Management
with responsibility for Research and Technology and head of
Development within the Mercedes Car Group. According to a
representative random analysis of the latest accident statistics,
Mercedes-Benz passenger cars have been involved in serious
accidents much less frequently than cars of other brands ever
since ESP was incorporated in large-scale production. While in
1998/1999, the share of newly registered Mercedes-Benz models in
the total number of cars involved in accidents was 20.7 percent
on average, this figure had declined by more than 42 percent by
2002/2003 thanks to ESP. By contrast, the proportion of cars
from other brands in the number of cars involved in accidents
declined by just 13 percent. Weber: “Alongside the seat belt,
airbag and ABS, ESP is by far the most significant safety system
of modern passenger cars.”
ESP improves handling safety by selectively decelerating
individual wheels, thereby counteracting the car’s tendency to
skid near the critical limits and retaining the driver’s control
of the car. Oversteering on corners is corrected by the
deceleration of the outer front wheel, understeering by the
deceleration of the inner rear wheel. In addition, ESP is
capable of throttling engine output with the aim of reducing the
car’s road speed.
The history of ESP
Arjeplog, northern Sweden, March 1994: On the frozen Lake
Hornovan, two Mercedes-Benz test cars drive lap after lap. While
one of them remains dead on course in completing the circular
course, the driver of the second car clearly has problems in
staying on course. Time and again, the rear of his car breaks
away on the black ice, forcing him to countersteer and
accelerate anew. Standing at the edge of the track, journalists
from all over the world watch the tests, witnessing the world
premiere of a milestone in automotive engineering, one that has
jointly been developed by Mercedes-Benz and Robert Bosch GmbH.
The test car that remains on course is equipped with the active
handling safety system ESP. Less than one year after the press
presentation in Arjeplog, this ground-breaking new system is
incorporated in large-scale production at Mercedes-Benz: The S
600 coupe (C 140 series) is the world’s first car to feature
this system, followed a few months later by the S-Class sedan (W
140 series) and the SL roadster (R 129 series).
First patent as early as 1959
As early as 1959, Professor Fritz Nallinger, Chief Engineer and
a member of the Board of Management of Daimler-Benz AG, filed a
patent for a “control device” that was to prevent the spinning
of the driven wheels through engine, transmission or brake
intervention. His idea was good but remained theory for a long
time to come because the relevant prerequisites – sensors and
control units capable of intervening with a stabilizing effect
in split seconds – simply did not exist. It was not before the
advent of microelectronics that progress became possible.
Microelectronics proved its suitability for everyday use in the
anti-lock braking system (ABS) which made its debut in the
S-Class (W 116 series) in 1978. At the same time, the ABS
created the foundation for the development of additional
systems. It served as the basis for acceleration skid control (ASR,
production start in 1981), which controls the longitudinal
forces between tires and road surface not only during braking
but also, and for the first time, during acceleration, acting on
both the brakes and the engine. This was followed by the
automatic locking differential (ASD, 1985) and the innovative
permanent four-wheel drive 4MATIC (1985). A common feature of
all these systems is the recording and limiting of wheel slip by
means of advanced microelectronics and hydraulics with the aim
of improving the so-called longitudinal dynamics of the car.
Handling safety under all conditions
But the Mercedes-Benz engineers were still not satisfied. Their
next goal was to improve handling safety under all conditions,
i.e. also during cornering, in evasive maneuvers or in other
transverse dynamic vehicle movements with a high risk of
skidding. They therefore launched another ambitious development
project. Under the working title “transverse acceleration
control”, the engineers investigated technical means of
identifying skidding movements of a passenger car and reducing
them by means of selectively controlling running gear, engine
and transmission. After extensive computer simulations and
preliminary investigations, the first tests with such a system
were staged in 1987, and in subsequent years, thousands of test
kilometers were driven. At the same time, the system proved its
suitability for everyday use in the driving simulator in Berlin,
where the Mercedes-Benz engineers sent 80 male and female
drivers onto a trip along an imaginary country road at a speed
of 100 km/h, incorporating treacherous black-ice traps with
tire-to-road adhesion reduced by over 70 percent on four corners.
The result of the tests: without ESP, 78 percent of the drivers
had no chance of keeping the car safely on course and skidded
off the road up to three times in succession. With the active
handling safety system engaged, however, all tests were
completed without skidding and without accidents. Small wonder,
therefore, that the Mercedes-Benz engineers did not hesitate to
test ESP on real-world roads. Series development began in 1992.
More than 40 engineers from Mercedes-Benz and Bosch worked
together on this ground-breaking project which was completed
with the incorporation of the system in large-scale production
in 1995. |
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