Delphi's passive occupant detection system is fitted to the 2003 Cadillac Escalade ESV.

Front passengers of select 2003 General Motors full size pick-up trucks and sport utility vehicles have a reduced risk of airbag-induced injury via a system that decides whether to deploy or suppress the safety device. Delphi Corp.'s second-generation Recognition Passive Occupant Detection System features a fluid-filled, seat-based load sensor as well as a seatbelt tension sensor. (The first generation of the system did not incorporate the seatbelt tension-sensor aspect.) The 2003 Chevrolet Suburban, GMC Denali, and Cadillac Escalade, are among the first automobiles in compliance with FMVSS 208 regulations.

"The system measures the seated weight of the occupant and then turns that weight into a pressure reading," said Joe Garcia, General Motors Airbag Safety Development Engineer, adding, "The pressure reading is sent to the electronic control unit and along with the belt-tension sensor, it determines an overall pressure signal. Based on the overall pressure signal, it determines whether it's above or below an airbag-enabled threshold."

To suppress the airbag, input from the weight-pressure sensor must indicate the weight is at or below the combined mass of a six-year-old child in a booster seat, or the safety-belt sensor must indicate that belt tension is above 15 lb (6.8 kg). An enabled airbag means the pressure sensor, mounted under the passenger seat cushion, must indicate a weight at or above that of a properly seated 108-lb (49-kg), 5th percentile female occupant, and the safety-belt tension sensor must indicate a value below 15 lb (6.8 kg).

Through the use of occupant classification algorithms and signal processing, the vehicle airbag controller is notified to deploy or suppress the passenger airbag. The seat-belt-tension sensor uses an algorithm compensation feature as a means of determining whether a child seat with a tightly cinched seat belt or a person is occupying the seat.

"The end result is a product that is robust, meets government and customer requirements, is easily adapted to nearly every vehicle seat type, and has achieved unprecedented market success," said Delphi engineer Craig Tieman, Chassis Safety Product Marketing Manager.

- Kami Buchholz

Bosch and the new E-Class

The Mercedes-Benz E-Class can be fitted with a dynamic multicontour seat, for which Bosch supplies the control until with integrated valve block and the sensor technology with air pump.

Among the many technical innovations on the new Mercedes-Benz E-Class, two significant electronic contributions by Bosch include a battery management system and the active seating technology that helps make the dynamic multicontour seat possible.

In the year 2000, some 15% of all vehicle breakdowns were due to dead or defective batteries, according to ADAC (German Automobile Club) statistics. The aim with battery management systems is to help to avoid breakdowns, as well as prevent exhaustive discharges, adding to the service life of the battery.

The electronic battery management system, which Bosch calls EBM 1.0, is designed to ensure a sufficient electrical energy supply to the car's various systems under varying operating conditions. The condition of the battery is all the more important since car buyers are insisting on more comfort features, such as seat heating or additional electrical heating, which are increasing onboard electrical load requirements.

The E-Class EBM measures temperature, voltage, as well as energy flow to determine battery state-of-health and -charge. It also allows for reliable prediction of the expected state-of-charge based on a charge profile continuously adapted to the changing conditions of the onboard network. If the state-of-charge threatens to fall under a defined value due to a continuing negative energy balance, the information is passed via a CAN bus to a central control unit. To guarantee a stable and reliable electrical energy level, the control unit can switch off the energy supply to all nonsafety-relevant loads or reduce the supply in a targeted way to safely satisfy higher priorities. And when the end-of-service life for the battery does approach, the system will forewarn the driver in advance.

For the optional E-Class dynamic multicontour seat for driver and front passenger, Bosch developed the adaptive-control technology. Used for the first time in the E-Class, the seat provides improved long-distance comfort and lateral support for sporty driving via five inflatable bolsters for adjustability of the four-way lumbar support, side bolsters, and seat-bolster depth. Used in other Mercedes-Benz models, the E-Class application adds dynamic adjustment of backrest side bolsters and a massage function. A control unit with integrated valve block and sensor technology adjusts the air pressure (thus size) of the bolsters (via a pump with accumulator) to the driving conditions.

The system receives information on driving conditions via a CAN bus from, among other sources, the vehicle's Electronic Stability Program to react immediately to the needs of the driver. A switch on the seat allows the driver to select individual static contour settings, control the massage function, and activate/deactivate the dynamic lateral support. The selected static seat contours can be memorized and be activated by key, keyless-go card, or memory button.

- Kevin Jost

Pacifica power/control module from Yazaki

The 2004 Chrysler Pacifica enters the market in the spring of 2003 on a new platform with Yazaki North America's Integrated Power Module.

The 2004 Chrysler Pacifica uses second-generation technology to power vehicle devices as well as control functions of electrical systems not associated with engine, chassis, or safety system duties. Yazaki North America's one-piece integrated power module (IPM) essentially "reads both digital and analog device inputs (i.e., from switches, sensors, other modules), analyzes the inputs, and acts accordingly—turns on/off power to a device, sends a message to another module, or sets a diagnostic code," said Andy Russo, Director of Sales, DaimlerChrysler Business Unit for Yazaki North America.

A first-generation integrated power control module appeared on the 2002 Dodge Ram as a two-piece unit. (Yazaki supplied the assembly's power distribution center; Motorola supplied the front control-module assembly.) The second-generation module "houses both a power board PDC (power distribution center) and digital core FCM (front control module) in a single housing. Component capacity is: 18 cartridge fuse links, 21 mini fuses, 7 mini ISO relays, and 11 micro relays. "The Pacifica's integrated power module also contains one PTC (Positive Temperature Coefficient) device, but does not utilize any board-mounted relays," said Russo.

The second-generation module is about 15% smaller in volume and has added features in comparison to the first generation module. "The Pacifica's IPM has more functionality than the 2002 Dodge Ram's IPM while having only 57 conventional components—i.e., fuses and relays—versus 73 conventional components in the Dodge Ram IPM," said Russo.

High-temperature-rated nylon-based plastic is the underhood IPM's housing material on the Pacifica. "By integrating the electronic components into the larger power distribution center, which includes metal substrates, it actually becomes easier to dissipate the heat," said Russo.

Pacifica's IPM can handle a number of functions, including rear heated seat and rear washer-wiper power/control, as well as power for the sunroof, door node, liftgate, manifold tuning valve, radiator fan, and navigation system. "The Pacifica IPM also has expandability for the addition of heated steering wheel and headlamp washer power/control," said Russo, adding, "The important thing to note about the increase in functionality and decrease in packaging volume is that it is accomplished not only by combining two modules into one, but also through the utilization of more electronics for power and control."

Although the IPM is not new technology, the Pacifica application represents a milestone. "It is the first mainstream, high-volume use of an underhood-mounted, one-piece module that handles most power distribution and body control functions through the use of solid-state electronics instead of conventional fuses and relays," said Russo, adding, "Although the IPM is not 100% solid state, it does go a significant way toward achieving that goal."

- Kami Buchholz