Defining that wow feeling

In the past, when developing vehicles with internal combustion engines, individual components such as the engine, chassis and brakes were separately engineered for peak performance and only subsequently harmonised with each other in the vehicle. In contrast, electric vehicles’ systems are more closely interconnected. This has to be factored into the development process from the start.

Kay Friedmann puts it in a nutshell: “We not only develop components with outstanding properties, but also optimum vehicle characteristics. That’s important because individual systems interact to a much greater extent in an electric vehicle.”

When choosing a conventionally powered vehicle, customers can pick a specific engine option—for instance, a four-cylinder TFSI or even a V6 power plant. When it comes to electric vehicles, however, there are probably very few customers out there who consider the difference between an asynchronous motor or a permanently excited synchronous motor to be a deciding factor. What matters is the overall performance of the powertrain. As Friedmann says, “There’s no point in building a high-performance electric motor if the high-voltage battery can’t put that power to work in the vehicle.”

For another example, look no further than the interaction between the traditional braking system and the electric motor’s recuperation behavior, which together are responsible for slowing the vehicle. This means that exceptional deceleration capabilities go hand in hand with the special nature of the thrust behavior.

What’s more, the fact that the car comes with electric motors on the front and rear axles as standard opens up a lot of new potential for refining driving dynamics at the upper end of the performance range. As a result, the chassis developers enjoy greater freedom in achieving optimum handling.

These new aspects call for a 360-degree approach to development. To this end, Audi has already pooled everything related to energy supply, storage and distribution in a single organisational unit. Looking ahead, this approach will be taken a step further by combining drive and chassis development into a single unit. Consequently, the drive, steering and braking systems will be controlled via an intelligent network.

Taking their cue from customer needs, interdisciplinary teams establish vehicle characteristics, which then form the basis for defining the development requirements. It’s essential that the engineers in the development departments are given a feasible brief in addition to specific use cases and special guidelines that illustrate the requirements.

The focus must always remain squarely on what the customer will “feel” in the vehicle. Kay Friedmann explains: “The fact that, on paper, a vehicle can accelerate from zero to 100 kilometers per hour in five seconds is no longer enough. What the driver experiences in the process is equally vital. In other words, what does the acceleration gradient look like? Is it linear, concave or convex? Will I feel myself being pushed back into my seat?”

Electromobility opens several new doors to engineers. What used to require a laborious mechanical development process can now be easily fine-tuned with electrical controls. In other words, what you achieve by precisely injecting fuel into the combustion chamber in a conventional car can be replicated by precisely controlling phases in the electric motor’s power electronics.

How much power does the motor receive at any one time and how does the vehicle drive as a result? Another Audi engineer, Roberth Eichner—project manager for the proof of concept vehicles and functional aspects—paints a picture of how this works. His team tests and experiences various drive functions for the first time. And they do so with the Brutus concept car, which is Eichner’s responsibility.

A former Audi e-tron prototype, Brutus is equipped with a wide variety of functional applications and measurement technology that allow various features to be activated at the touch of a button and experienced live. “This is what makes electromobility so fascinating—the fact that we can switch on a range of functions in this proof-of-concept vehicle and thus lend Brutus a broad spectrum of character traits,” says Roberth Eichner.