Technical Developments out of Friedrichshafen & Beyond

What is it? Smart Urban Vehicle.

What you need to know about it. This is an electric vehicle. One that ZF has engineered to be able to do things that other EVs can’t. A primary reason for a difference in its capability: the front axle provides steering angles of up to 75°. 

The rear axle setup is important in this regard, as well. The semi-independent rear suspension setup is called an “electric twist beam.” There are electric motors in aluminum housings on both the right and left sides (these are not wheel motors; they are located just inboard of the wheels). Each provides 40 kW for propulsion. The axle torque is 1,400 Nm (1,032 lb-ft). The vehicle can travel at up to 150 km/h (93 mph).

The ability of the front wheels to turn supplemented by the torque vectoring provided by the rear motors allows the car to have a turning circle diameter of less than 7 m (23 ft). This means that the vehicle is ideally suited to maneuvering in conjected urban environments.

One of the things that it does exceedingly well is fit into tight parking spaces. This is not only because of the extreme steering angle, but also because of another technical development, named “Smart Parking Assist.”

Smart Parking Assist makes use of 12 ultrasonic sensors and two infrared sensors that are deployed around the vehicle. These sensors are used to determine whether a suitable parallel parking space is located. Then the driver can activate the self-parking feature.

Not only can the self-parking system be deployed when the driver is behind the wheel of the vehicle—and more about the steering wheel in a moment—but the driver can also control the vehicle through an Android-based smart watch or tablet from outside of the vehicle.

This out-of-the-car capability gives rise to the possibility of autonomous parking. According to Dr. Harald Naunheimer, Head of Corporate Research and Development at ZF, “When implementing the concept, we weren’t only looking at the benefits for the driver. If passenger cars in the future park without a driver, parking space can be used more effec-tively. As such, the door opening angles would no longer need to be taken into account in the parking garage—thus making the parking spaces smaller. All of which also takes the pressure off cities because the freed-up space can then be used productively as additional living and working areas.”

Then, of course, there is what everyone from Amazon to automakers are talking about: the cloud.

Another function that ZF has developed for demonstration in the Smart Urban Vehicle is called “PreVision Cloud Assist.”

Essentially, the vehicle communicates driving information to the cloud. This is not just GPS coordinates, but also information about speed and lateral and longitudinal information.

Say this is the route that you drive home every day. Information about the route and how you drive the route are stored in the cloud. Then it is possible for the PreVision Cloud Assist to control the car such that when going into a curve, the amount of acceleration is adjusted to best handle the curve without requiring any braking, which helps maintain battery charge (remember: this is an electric vehicle).

Another capability that the PreVision Cloud Assist provides would be predicated on there being multiple vehicles so equipped. By having that information sent to and from the cloud, it is possible for the assistance function to be predicated on the data from multiple vehicles, thereby optimizing the vehicle’s driving performance.

(Note: During a drive on a test track in a vehicle with PreVision Cloud Assist inactive and then active, the difference between how I accelerated and braked and how the car with the system active performed based on information from how several other people who had previously run the route was discernable.)

Which brings us to the aforementioned steering wheel. There are two key aspects to the wheel in the Smart Urban Vehicle. One is an organic light-emitting diode (OLED) display that is located at the 12-o’clock position on the wheel. This provides information regarding how the PreVision Cloud Assist system is performing.

The other is a full capacitive system around the entire wheel that is capable of determining whether the driver’s hands are on the wheel. The information obtained by the steering wheel sensors is sent via a local interconnect network to the vehicle controller. Depending on the conditions assessed by the vehicle’s sensor system, automated driving can be activated.

Explained Dr. Alois Seewald, Technical Director of Integrated Active & Passive Safety Technologies at ZF TRW, “With the hands-on detection, we are creating the basis for assistance and automated driving functions which reduce the driver’s workload, such as in urban traffic, which is characterized by strenuous stop-and-go phases during rush-hour periods.”

What is it? Eight-speed automatic transmission for hybrids.

What you need to know about it. ZF has been producing eight-speed automatic transmissions since 2009, and during this time, it has deployed the transmission in some 600 different production-vehicle applications. The company has developed a second-generation transmission that is more efficient than the first (primarily by addressing internal drag losses).

And this second-generation model is sufficiently modular such that a hybrid version has been developed that has improved torsional vibration decoupling thanks to the use of two dampers, one of which is a speed-adaptive damper. This means that compared with the first-gen version, this transmission operates at high loads from idling speed without jarring noises or vibrations.

There is an electric motor, designed as a permanent field synchronous machine, that is integrated into the transmission housing. It provides peak output of 90 kW and constant power of 45 kW. Depending on the type of battery system used in the vehicle, the transmission is capable of providing an electric range of up to 50 km (31 miles).

What is it? Lightweight rear suspension.

What you need to know about it. In order to reduce mass in the rear suspension setup and to achieve part consolidation, ZF engineers developed a McPherson-style system that includes a trailing link, toe link, wheel-guiding damper, and, most importantly, a wheel-guiding traverse spring.

Notably, the spring is made with glass-fiber reinforced plastic rather than steel. Not only does this mean that the com-ponent is lighter, but the component was engineered such that the spring serves several functions, including that of a chassis control arm.

In terms of mass, the weight of the system is approximately 13% less than a conventional multilink suspension. Due to the multi-functionality of the spring and the consequent part count reduction the setup is said to be cost neutral.

What is it? Semi-automated driving system.

What you need to know about it. One of the reasons why ZF acquired TRW is because of its capabilities in steering, braking, suspension . . . and sensors. All key elements of autonomous driving systems.

Said Peter Lake, executive vice president, Sales and Business Development, ZF TRW, “We’re following a building-block approach to automated driving functions.”

And they put together a system that they’re calling “Highway Driving Assist” that combines an AC1000 79 GHz radar system, an S-Cam 3 video camera sensor, Electrically Powered Steering Belt Drive, and Electronic Stability Control EBC 460. The combination results in adaptive cruise control (ACC) and lane-centering assist (LCA) capabilities when a vehicle is driving at speeds above 40 km/h (25 mph).

In other words, the car is capable of automatic steering, braking and acceleration. The ACC keeps the vehicle at the preset speed or, if a slower car is encountered ahead, then slows to maintain a preset gap between vehicles. The LCA, using the forward-looking camera, makes sure that the car stays centered between the lane markers.

The next step is to use a 360° sensor system that will permit lane changing. This will be predicated on making sure that the selected lane is open for moving over. The driver will indicate the lane change by using the turn signal, then the vehicle will shift lanes.

Lake: “The next decade represents a huge opportunity to improve not only the driving experience, but fundamentally road safety.”