| Bosch puts the brakes on |
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Accident researcher Professor Klaus Langwieder explains why side impacts are more serious: “In contrast to the deformation zones in the front and rear end, a passenger car offers fewer options when it comes to side-impact protection – this is evidenced by the large numbers of seriously injured or killed people in side collisions.” Based on the study, the Institute for Vehicle Safety issued a clear recommendation in favour of electronic safety systems that enhance vehicle stability, such as Electronic Stability Programme (ESP). Since that study, the motor industry as a whole has recognised the benefits of ESP, as evidenced by the startling increase in systems made by Bosch. After starting production of ESP in 1995, Bosch had produced three million systems by the end of 2000. Just two years later, halfway through 2002, Bosch made its 10-millionth system. As is virtually always the case, ESP started out the preserve of the premium car market, but no more. ESP is now available on the Smart, Renault Megane, Toyota Avensis, Toyota Corolla, Nissan Primera and the VW Polo. At the heart of ESP is a small computer, or controller, which is constantly fed information from sensors around the car. These compare the vehicle’s speed and direction with the position of the steering wheel, looking for signs that it is starting to break away from its intended course, or that it is starting to swing round sideways. If it spots this starting to happen the ESP controller sends signals to a hydraulic modulator which can brake individual wheels to help bring the car back on track. It can also tell the engine management to cut engine power to stabilise the vehicle.
“Of course, ESP cannot overcome the laws of physics. However, through targeted intervention, the system can do everything physically possible to prevent the vehicle from skidding – much better by far than even the most experienced driver." Since it first introduced ABS 25 years ago, Bosch has constantly introduced new brake control technology. Traction control, a system first developed in motorsport, followed shortly after and today ESP, which utilises both of these previous technologies, represents the greatest step forward in road safety for some time. And it does not stop with ESP. Bosch, and the automotive industry as a whole, refer to modern braking systems as active braking systems. This is because they all incorporate electronic control that, independently of the driver’s actions, can apply braking in different ways to achieve the optimum effect. By adding extra sensors and more powerful software, electronic braking control also allows for the introduction of a wide range of additional functions, each bringing safety and comfort benefits.
Cornering Brake Control selects separate and optimum braking pressures for each of the inside and outside wheels to increase directional stability during normal braking through a corner, giving a smoother ride, with less body roll. Drive-Away Assist prevents the car from rolling backwards or forwards on hills or steep drives – stepping on to the brake pedal quickly, but sharply, activates the function. “Soft-Stop” ensures gentle and smooth stopping, a significant comfort benefit around town. Adaptive Cruise Control uses signals from sensors at the front of the car to enable the cruise control system to proactively reduce speed, or even brake, in order to maintain a safe distance to the vehicle in front. Traffic Assist, linked to Adaptive Cruise Control, offers benefits during stop-and-go traffic. The driver only needs to use the accelerator pedal; once they take their foot off the accelerator the brake system will take over and bring the car to a standstill at a steady rate. As well as the introduction of these additional functions, electronic control has paved the way for a whole new era of braking, referred to as “brake-by-wire”. Brake-by-wire replaces the hydraulic part of the brake system with electric motors, all controlled centrally, creating faster braking times and allowing for even greater integration of additional braking functions. The world’s first example of brake-by-wire for passenger cars is a hybrid system referred to as electro-hydraulic braking by Bosch and named SBC by Mercedes, which pioneered it in its SL. Such was the success of the application of the system – reducing braking distance by an estimated 3% at 75 mph – that Bosch and Mercedes-Benz were given a special award by an association of approximately 350 international brake and safety specialists. Another significant step forward resulting from electronic control is the development of a better relationship between tyre, road conditions, and braking system. Bosch has entered into an agreement with Michelin to develop integrated vehicle dynamics management systems that offer improved safety and mobility. One of the first objectives of the project is to increase vehicle mobility in the event of pressure loss in a tyre by applying Michelin’s run-flat tyre solution in combination with ESP or further brake-by-wire systems from Bosch. This system could be seen on passenger cars as early as 2004.
The safety benefits of these developments are clear, but the automotive industry has to be able to integrate them in an economically viable way. Bosch is helping this process with innovations such as its Generation 8 modular electronic-braking platform, which offers vehicle manufacturers’ upgradeable configurations for ABS, Traction Control and ESP in a single unit. At just 1.6kg, it is 900g lighter and almost 40% smaller in volume than previous versions. Bosch’s expansion within this field to become a manufacturer of complete braking systems in the mid-90s is now paying off. Already a leading supplier across Europe, last year Bosch gained a major new order that will make it the largest supplier of chassis systems by far in North America by 2006. This success will ensure Bosch can continue to develop braking systems that make our roads safer. |
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