A variable steering ratio makes turning into parking spaces and around corners easier while delivering greater precision with less effort. Enjoy getting completely misdirected. A variable steering ratio is used in progressive steering to provide more precision with less effort and a more immediate steering reaction.
In This Article...
Describe Audi steer.
A competent steering wheel should be able to handle all types of driving conditions, whether you’re traveling on busy highways, bustling city streets, or pothole-filled city streets on your way to the grocery store. In this interview, Carsten Jablonowski, Team Lead for the Development of Driving Characteristics, describes the difficult process of adjusting the chassis and steering, which gives an Audi its distinctive steering feel.
How would you characterize the typical feel of an Audi steering wheel, Mr. Jablonowski? The way a car’s steering feels to us when we’re in the driver’s seat varies depending on a number of variables. The general layout, the weight and weight distribution of the vehicle, the particular chassis parts, the tires, and the steering system all come into play. Now that I’ve driven several different Audi models, I quickly recognize the familiar sensation of how easily, smoothly, and precisely the car steers. And this holds true whether I’m parking, navigating tight corners, or just driving about the city.
I can navigate curves precisely and quickly because an Audi steering wheel produces more torque. Our models have extremely accurate direction changes, especially when moving quickly via alternate turns. On the other hand, an Audi is completely jitter-free and will smoothly drive straight ahead at high highway speeds. The car’s interaction with the road is thus constantly apparent to me. The steering wheel directly informs me of the car’s balance, grip level, and road irregularities like potholes and ruts. Overall, this is critical for a secure and enjoyable driving experience.
The creation of a vehicle can take up to five years. How can you make sure that steering feel is given enough thought at this time? The handling characteristics for the respective series are first defined. Each model has a specified range of acceptable steering angles. The front steering axle’s transmission ratio curve or necessary steering ratio are among the characteristics that are determined by this. The front axle steering system is then created in accordance with this. We also use rear-axle steering due to the increased demands on driving dynamics and handling in larger vehicles like the Q7 and Q8.
How is a steering system calibrated in the real world or on a computer? Both. The majority of what we refer to as basic calibration is done online. Over the course of a vehicle’s complete speed range, we recreate standardized driving and steering procedures that we have established. We primarily concentrate on the linear range, with low lateral forces and typical steering frequencies, that the typical customer typically drives. In addition, we test the vehicle’s handling under extreme lateral acceleration and rapid steering frequencies. With this method, basic calibration performs quite well, even for intricate systems like dynamic all-wheel steering. However, it definitely does not provide outcomes deserving of final approval.
What comes next in the process of fine-tuning? Through simulations, it is currently not able to adjust and harmonize all of the chassis parts. Only after we put the steering through its paces can we accurately evaluate how it feels. To check whether the parameters we chose at the initial calibration are in the proper direction, trials are necessary. We first test-drive the car on various test tracks for this reason. During the calibration procedure, both objective and arbitrary criteria are taken into consideration. We ponder things like: How is the self-steering behavior of the car? Do the driver’s commands reach the wheels directly or indirectly through the steering wheel? Does the driver get a decent sense of the road’s surface? Is the steering wheel quick to respond or hesitant?
What should you do if you find that the wheel hasn’t been adjusted correctly? We make the required adjustments and immediately set off for the next test drive if a test drive reveals that something has to be altered or that we should attempt a different setting. We modify the control unit’s parameters while taking various drive and tire configurations into consideration. On public roadways, a lot of the calibration and fine-tuning is done. After all, this is where the automobiles will eventually carry out their daily operations. We improve the standards and the system as a whole with each calibration run until it is eventually ready for production.
How do you particularly handle the original tire issue in this context? In the end, our cars’ cutting-edge technology is made possible by the tires. The driving and steering characteristics of the vehicle can be dramatically altered by choosing different tires. This means that the chassis and steering system must work flawlessly as a unit. It takes time for a new Audi and a certain kind of tire to become the ideal combination. We create a suitable tire composed of cutting-edge materials specifically for each Audi model in collaboration with top manufacturers. In this process, we align our requirements with the selection of tires that our partner firms have to offer. An original Audi tire must fulfill a large list of requirements during thorough testing.
What standards are involved here? The summer and winter tire designs go through various rounds of fine-tuning before we are happy with their performance in terms of runout quality, rolling resistance, driving dynamics and handling, braking characteristics, fast running, aquaplaning, winter testing, and uniformity. The tread rubber compound, carcass, and tire substructure are continuously customized to the vehicle model during the procedure. We raised the bar during the development process above what was required by law. A tire can only be sold on an Audi after about 50 testing. We travel 40,000 kilometers in total during our endurance testing.
Currently, Audi offers a variety of steering methods. What advantages does this have? The foundation for all of our steering systems was set by our electromechanical power steering system. This mechanism makes it possible to adjust the steering help based on speed. The development of progressive steering was based on this concept. This uses a progressive transmission ratio to operate as the name says. This implies that depending on the steering angle, steering movements are conveyed differently. This significantly lessens the amount of effort needed to steer the car while turning and parking. But because the steering is more direct, the driver will experience a more dynamic response on curvy country roads and when turning. When dynamic steering was introduced, the rise followed. It enables the steering ratio to be changed independently of the steering angle. This fixed a number of technical issues. Additionally, drivers can use Audi drive choose to modify the steering ratio to suit their demands.
Then there is dynamic all-wheel steering, which is currently the best technology available for steering systems. What advantages do rear-axle steering provide? The inclusion of rear-axle steering, sometimes referred to as all-wheel steering at Audi, greatly enhances the handling of the car. Every single one of us has inadvertently crossed the kerb in a tight parking garage while advancing to the next level with the inside rear wheel. This is no longer as common because of the all-wheel steering. The rear axle is directed counterclockwise to the steering wheel angle when traveling at a slow pace. As a result, the vehicle’s path is narrower and its turning radius is substantially lower when moving. On the other hand, if you’re moving more quickly, the steering is done in the other way. Driving stability is greatly increased as a result of the wheels turning in the same direction on both axles, especially when passing. The benefits of dynamic and all-wheel steering are ultimately combined in dynamic all-wheel steering. In that regard, we continue to gain from earlier innovations.
Uses electronic steering in Audi?
The electromechanical power steering in the A6 and A7 Sportback can also be upgraded with Audi active lane assist, which aids the driver in maintaining their lane. The full-size versions’ park assist technology is also a particularly potent feature.
The definition of progressive steering
A constant steering ratio is used in conventional steering systems. Progressive steering is based on a progressive steering ratio, as the name suggests. This considerably lessens the effort needed for parking and low-speed maneuvering. The driver will experience a more dynamic response due to the more direct steering on curvy roads and at intersections. Additionally, there is a lot less need to exchange money. Progressive steering differs from electromechanical steering in that it has a more potent electric motor and changeable tooth spacing on the rack and pinion.
Progressive power steering: what is it?
Another speed-dependent steering aid is progressive steering. The progressive gearbox ratio enhances automobile handling at high speeds while greatly reducing steering effort at low speeds or during parking. Progressive steering gives improved control during sporty driving as well as added convenience when used often.
How does all-wheel steering in an Audi work?
Currently, five different steering systems from Audi let the vehicle move quickly, comfortably, and safely through traffic. With Audi’s typical steering character, which guarantees accurate and dynamic application of steering movement, they symbolize effortless, controlled driving across various models. The Dynamic All-wheel Steering is the best system. With that system, Audi is combining manageability with incredibly high precision while pushing the boundaries of what is physically feasible.
The state-of-the-art power steering system in today’s premium vehicles is electro-mechanical. Without hydraulic components, the system operates and uses considerably less energy as a result. Additionally, it theoretically enables all steering-interactive assistance systems. Directional stability is improved and steering assistance with a speed adjustment is provided by electro-magnetic power steering. This gives the driver a dynamic steering feel and provides the driver with feedback from the road that is incredibly precise and highly differentiated.
“Progressive” refers to steering that is applied differentially based on the steering wheel’s angle. The steering rack and pinions are designed and geared specifically to accomplish it. The gear ratio is smaller and the steering is more direct at a steep steering angle. It just takes two and a half rotations of the steering wheel to go between the two maximum settings when the driver has to maneuver or park. Due to the more direct gearing, drivers will enjoy a more dynamic ride on winding roadways. Power steering boost is adapted to vehicle speed. It rises to a high height for easier handling at low speeds and falls as speed rises. At Audi, electro-mechanical progressive steering is the most often used steering system.
Depending on the driving speed, steering angle, and mode chosen in the Audi drive choose dynamic handling system, dynamic steering can be applied up to 100% of the time. The superimposition gearing in the steering column is the key element. Similar to a car with a traditional steering column, it transmits the driver’s steering inputs clearly. Additionally, there is a direct mechanical connection between the steering gear itself, which is located on the front axle, and the forces on the wheels that it responds to. By increasing or decreasing the steering angle under the control of the electric motor, the superimposition gearing continuously modifies the steering ratio to suit the current driving circumstance. This enhances the tracking behavior and steering comfort depending on the vehicle’s speed and driving conditions. Dynamic steering works very directly when driving at moderate speeds in city traffic and when navigating; two complete spins are all it takes to move from one end stop to the other. Parking and maneuvering are made simpler by the strong power steering boost. On back roads, the steering response’s directness and the electric assistance gradually deteriorate. In order to eliminate jerky steering motions and permit straight tracking at high highway speeds, indirect gear ratios and low power assist are used.
Audi pioneered all-wheel steering with the Q7 in 2014 and raised the bar for agility in the process. The system has individual steering angle controls for the front and back axles. It employs an electric spindle drive and two tie rods for the rear axle steering and electro-mechanical power steering for the front. Drive-by-wire technology is used to electrically send the turn signal to the steering linkage and actuators in the back of the vehicle. At slow speeds, the rear wheels can rotate up to five degrees counterclockwise to the front wheels. This lessens the turning radius by around one meter (3.28 feet), which is very useful when navigating and parking.
However, from a speed of roughly 60 km/h (37.28 mph), the rear wheels travel in lockstep with the front wheels. Driving behavior at highway and expressway speeds is generally calmer and more stable while turning up to two degrees in the same direction. Additionally, Audi’s luxury-class SUVs are among the most nimble vehicles in their class thanks to all-wheel steering.
The Audi S81 comes standard with Dynamic All-wheel Steering, an advancement in all-wheel steering that is an option on the Audi A6, A7, and A8. It combines dynamic front- and rear-axle steering and is now the most advanced steering system offered by Audi. Audi is pushing the boundaries of what is physically possible with that system. The system has many advantages, particularly in the threshold range. It blends superb driving stability with a direct, sporty steering reaction, or, to put it briefly: manageability with very high precision. At low speeds, the overall steering ratio fluctuates between 9.5 and 17.0 direct, while being consistent at high speeds.
What is the electromechanical steering in an Audi?
Progressive steering with electromechanical technology improves comfort and driving dynamics. Depending on the steering angle, a specially interlocked steering rack on the vehicle changes the gear ratio. The steering becomes more direct as the steering angle rises. This lessens steering effort in maneuvering in city traffic, and the automobile is more nimble in tight turns. Additionally, progressive steering adapts its power boost to the vehicle’s speed. This increases for improved agility at low speeds.
Does fluid exist for electric power steering?
The three power steering systems all carry out the same crucial task, but they do so in three different ways. An electric system employs an electric motor and sensors, an electro-hydraulic system uses an electric motor to pressurize fluid, and a hydraulic system uses high pressure fluid that is physically pushed. The ultimate result is always the same: The steering wheel is simple to turn. Fully electric power steering systems are more dependable than hydraulic systems, use less fuel, and require less maintenance.
Hydraulic Power Steering
To reduce steering effort, this system uses pressurized power steering fluid, which is supplied by the power steering pump. High-pressure power steering fluid is delivered to the input side of the power steering gear-control valve via the high-pressure hose by the pump, which is activated by an engine-driven accessory drive or serpentine belt.
When moving the front wheels, the driver is helped by high pressure acting on the control valve. A reservoir is used to store the power steering fluid. When the fluid returns from the steering gear at a significantly reduced pressure, the reservoir’s proper fluid level is maintained. Systems with hydraulic power steering constantly pump fluid and are vulnerable to engine speed Low revolutions per minute provide low pressure, while high revolutions per minute produce high pressure. A power steering pump employs a bypass valve to maintain consistent pressure so that it is independent of engine speed.
Electro-Hydraulic Power Steering
Instead of using a serpentine belt or an accessory drive powered by the engine, these systems use a brushless electric motor to drive the hydraulic power steering pump. The functionality and feel of this system are identical to those of a traditional hydraulic power steering system.
Electric Power Steering or Motor-Driven Power Steering
Hydraulics and pressurized fluid are not used in this system. A brushless bi-directional permanent magnet motor attached to the steering gear or steering column rotates the front wheels whenever the driver turns the steering wheel. To help the steering gear turn in the right direction, sensors track which way the steering wheel is turned.
Power steering only affects the steering gear when the driver moves the wheel, regardless of the type of system you have.