As opposed to valve-based systems, Delphi's MagneRide semi-active suspension system has a monotube design with no electromechanical valves or small moving parts.

The 2002 Cadillac Seville STS will trade in its continuously variable road-sensing suspension (CVRSS) struts in midyear 2002 for Delphi Automotive Systems' next-generation variable damping system, MagneRide, which provides controlled, independent damping at all four corners of the vehicle. "(It) is an evolutionary, not revolutionary, technology," said Fred Wood, Development Engineer for the Seville, noting that not much has changed from the current suspension system other than the damper. Even so, MagneRide reacts at least five times faster than the current damper, said Wood, and will enable improved handling, ride quality, and road isolation as well as safety.

As opposed to valve-based systems, the MagneRide semi-active suspension system has a monotube design with no electromechanical valves or small moving parts for quieter operation—an industry first, according to the Troy, MI-based supplier. MagneRide consists of magneto-rheological (MR) fluid-based monotube struts and shock absorbers; a sensor set that consists of a relative position sensor between each control arm and the body as well as a lateral accelerometer and a steering-wheel angle sensor, which are also part of the Stabilitrak system (a yaw rate sensor is used indirectly by the MagneRide system in active-brake-apply events); an onboard controller; and an optional leveling compressor module, which has underbody or engine-compartment packaging capabilities and integrates with the existing sensors and controller.

The control system architecture for MagneRide. Click to enlarge

Delphi and Lord Corp. co-developed the MR fluid, which consists of suspended iron particles in a base fluid of synthetic hydrocarbon, specifically for the shock-absorber application. In its "off" state, the MR fluid is not magnetized, and the iron particles are dispersed randomly; however, in the "on" state, the applied magnetic field aligns the metal particles into fibrous structures, changing the fluid rheology and thus regulating the damping properties of the monotube struts.

Based on the wheel inputs from the road-sensing suspension—as well as driver inputs such as steering and braking—the system's onboard computer sends electrical currents up to 1000 times per second to the electromagnetic coils in each damper to change the flow properties of the damping fluid. According to Delphi, the MR fluid can change from a mineral-oil-like consistency for low damping forces to a jelly-like one for high damping within 1 ms. The result is continuously variable, real-time damping that provides the following benefits:

• Flatter ride through more controlled vehicle body motions and reduced wheel bounce, which greatly reduces heave, pitch, and roll
• Greater sense of safety and security due to improved road-holding capabilities on uneven surfaces and during braking
• Enhanced handling by controlling the lateral and longitudinal load transfer characteristics of the suspension during transient movements
• Reduction of high-frequency road disturbances transferred through the dampers
• Greater vehicle-dynamics control when combined with Delphi's Unified Chassis Control (see September AEI, page 30).

In the "off" state, the magneto-rheological (MR) fluid is not magnetized and the iron particles are dispersed randomly; however, in the "on" state, the applied magnetic field aligns the particles into fibrous structures, changing the fluid rheology and thus regulating the damping properties of the monotube struts. Click to enlarge

The new system also contributes to low-frequency body control and enhanced roll control during transient steering and evasive maneuvers. In addition, MagneRide integrates with other vehicle systems such as ABS and traction-control systems to further improve the car's performance, comfort, and safety characteristics. The operating temperature range for the dampers is -40 to +70°C (-40 to +158°F).

The MagneRide damping system will also be used on Cadillac's 2003 two-seat roadster.

- Ryan Gehm

Q45 gets latest Visteon Voice Technology

A button on the Infiniti Q45 steering wheel enables the car's Visteon Voice Technology.

Second-generation voice technology from Visteon Corp. makes its first appearance on an Infiniti vehicle, the 2002 Q45 sedan. Voice commands can control navigation, CD, radio, cassette tape, and climate functions. Voice command for a cellular phone will be available after initial launch.

Visteon Voice Technology interprets continuous word commands. "It's speaker independent, so it's not trained to one voice," said Bill Klingler, Voice Products Supervisor for Visteon. He added that slow, deliberate voice commands are counterproductive since the system "was actually designed for normal speech patterns."

Compared to first-generation Visteon Voice Technology (which debuted on the Jaguar S-Type), the second-generation product offering improves the human/machine interface (HMI). Consider the setup for personalizing/storing a radio station nametag; in the next-generation version, a voice command is given once instead of repeating the nametag storage command three times during HMI dialogue.

To issue a command, the user must press a button "so you always have control as a user as to when you want to issue that command," said Klingler. In the first-generation version, pressing a steering-wheel-located button activated the voice command system. The first-generation was also U.S./UK-limited. Second-generation Visteon Voice Technology adds Australian/English, German, Italian, French, and Spanish languages. However, the Infiniti Q45 application will be U.S./UK specific.

Engineers added more in-vehicle speakers during the second generation's product development phase. The additional speakers, used to monitor in-vehicle noise occurring from idle to about 113 km/h (70 mph), resulted in improved voice models. An omni-directional microphone in the headliner and a push-to-talk button on the Q45 steering wheel are the system's main hardware components. The command process starts at the microphone and ends with the SAE J1850 vehicle bus relay to control audio, climate, and navigation. "Voice technology is very software-intensive," said Klingler.

The technology on the Q45 provides speech-adaptation capability and can be particularly useful for people who speak English as a second language. When speech adaptation is employed, the system uses 25 phrases spoken by the user to adapt to that person's voice.

Future versions of the Visteon technology may see integration with other products—such as part of the audio/head unit—instead of today's stand-alone module.

- Kami Buchholz