Since 1980 Bosch manufactured precisely 111,111,111 airbag control units. They deploy the restraint devices based on the kind and severity of the accident, as measured by their sensors.

In 1977, Bosch started development of an electronic airbag control unit equipped with centrally positioned sensors. The first patent application with the title ‘trigger device circuit (alternative release mechanism) for a vehicle occupant restraint system’, was filed in March 1978. When the first system was installed in the Mercedes-Benz S-Class saloon, it consisted of three separate components: an electronic control unit, a voltage converter, and an energy storage unit. In its basic configuration, the latest generation of the system, dubbed Airbag 10, takes up some 70 percent less space and consists of a single control unit.

Airbag performance has improved steadily over the years. Deployment systems now include additional sensors installed in the side panels of the vehicle that make it possible to determine the force and direction of impact more quickly. Other sensors installed inside the passenger cell provide information on the weight and seating position of the driver and front-seat passenger. If the vehicle occupants do not weigh much or are leaning forward, the airbag release mechanism is inhibited or fired in gradual stages, reducing the risk of injuries. Additional functions to prevent injury to pedestrians, such as automatically raising the hood in the event of a collision, can also be integrated into the safety system. Current control units are capable of controlling up to 32 restraint devices including airbags and seat belt pretensioners.

Since airbag technology first went into series production 31 years ago, Bosch engineers have never ceased to refine it. The size and weight of the control units have been reduced by some 70 percent. The reduction in costs over the same period means that passive safety systems have become an affordable feature for buyers at all levels of the market. Bosch has even introduced a “light” version of its airbag control unit to meet the needs of the low-cost vehicle market in countries such as China, India, and Brazil.

Airbags have been standard equipment for a number of years in all vehicles sold in Europe, the United States, and Japan. On average, some 80 percent of new vehicles manufactured in the world are equipped with at least one airbag. In the BRIC states (Brazil, Russia, India, and China), however, the proportion is currently only one in two. Bosch started to manufacture the world’s first electronic airbag control units in 1980. The next year, they were incorporated for the first time into a series-production car, the Mercedes-Benz S-Class saloon, where they controlled the activation of the driver airbag and a seat belt pretensioner. Many cars today contain as many as nine airbags, together with belt pretensioning mechanisms that complement the action of the airbags, by further limiting the consequences of an impact for passengers.

The risk of fatal injuries to occupants of vehicles involved in road accidents in Europe was twice as high in the 1990s as in 2008. “The widespread introduction of airbags had a major impact that the number of road fatalities has been cut by nearly half since then,” says Werner Struth, the president of the Bosch Chassis Systems Control division. Driver airbags are also becoming increasingly common in emerging markets such as those of Asia and South America. In 2009, the governments of Brazil and Argentina adopted a resolution making it compulsory for all new passenger vehicles and light commercial vehicles to have front-seat airbags as of 2014. Bosch manufactures restraint systems in Europe, Asia, and North America.

Yet more safety functions can be introduced when airbag control units are linked with the sensors and systems used to provide driver assistance and vehicle communication. An example of such a safety function is Secondary Collision Mitigation, which links the airbag system with the ESP electronic stability program. If the collision sensors detect an impact, the ESP automatically applies the brakes to slow down the vehicle, reducing its kinetic energy and thus minimizing the force of a possible second collision.