The Audi RS Q e-tron and Q4 e-tron share Audi’s spirit of bringing electric mobility to all territories. The Q4 e-tron is the first electric Audi in the compact SUV segment, while the RS Q e-tron represents an innovative concept for competing in the Dakar with an alternative powertrain.
Audi’s goal with the RS Q e-tron is to demonstrate that electrification can also succeed on the toughest stage of motorsport and, at the same time, to develop innovative technologies that can be applied later in the development of production vehicles. The challenges during its design have been the energy density and performance required in a test like the Dakar, with daily stages with hundreds of kilometres, the enormous resistance generated by the fine desert sand, the high outside temperatures and a weight minimum of the vehicle fixed by the regulation of two tons.
The spirit of the Audi Q4 e-tron range is to offer electric mobility without compromise and to be a vehicle for everyone and everything. The Audi Q4 e-tron and Q4 Sportback e-tron offer a progressive design, a spacious interior, a high range (up to kilometers, WLTP), a fully digital user experience, safe, sporty and comfortable driving, and a wide range of driving assistance systems.
With their similarities and differences, both are the perfect companions for Carlos Sainz in his daily life and in competition.
Same base, different concept to get the most out of electric propulsion.
Different concepts to reduce the carbon footprint
“It is impossible to build a fully electric all-terrain vehicle to compete in the Dakar Rally using current battery technology,” says Lukas Folie, high-voltage battery engineer at Audi. “What we are going to try has never been done before, we are facing the biggest challenge for an electric propulsion system,” says Andreas Roos, head of the Dakar Project at Audi Sport.
The drive system of the Audi RS Q e-tron is electric. Since there are no opportunities to recharge the battery in the desert, an innovative concept has been chosen: a TFSI engine like the one used in the Audi RS 5 DTM acts as an energy converter in charge of recharging the high-voltage battery while driving. . The engine operates in a particularly efficient range between 4,500 and 6,000 rpm, allowing specific consumption well below 200 grams per kWh.
All of this technology is housed in a tubular steel frame with carbon fiber and cyclone structural components. The set has four-wheel drive and a suspension system designed to overcome all the obstacles of a test like the Dakar.
The Audi Q4 e-tron and Q4 Sportback e-tron have a self-supporting body made of high-strength steel and aluminum and are built on the MEB modular platform, designed for electric-powered vehicles. Depending on the version, they are equipped with one or two electric motors and rear-wheel drive or quattro, powered by a high-capacity battery that can be recharged from the mains, and which also receives a charge while driving through the recovery system. energy in deceleration or braking phases.
The difference between a street dashboard and the brutal dashboard of a Dakar vehicle.
electric propulsion
The Audi Q4 e-tron and Q4 Sportback e-tron have two battery variants and three engines to choose from to meet the demands of very different customers. The compact battery of the Q4 35 e-tron has a net capacity of 52 kWh (55 kWh gross); in the Q4 40 e-tron and Q4 50 e-tron quattro the capacity is 77 kWh net (82 kWh gross). The Q4 35 e-tron and Q4 40 e-tron have an electric motor that drives the rear wheels, with an output of 125 kW (170 PS) and 150 kW (204 PS), respectively. The top-of-the-range version, the Q4 50 e-tron quattro, has two electric motors, one on each axle, with a combined power of 220 kW (299 hp). Account, therefore, with electric all-wheel drive.
The Audi RS Q e-tron uses a motor-generator unit (MGU) on each axle like those used in the current Audi e-tron FE07 developed by Audi Sport for the 2021 Formula E season. The maximum power of the propulsion system electric is 500 kW (680 hp), but is limited to 288 kW by Dakar regulations. The round cell lithium ion battery system has a capacity of 52 kWh and weighs 370 kilos.
The RS Q e-tron has to use a gasoline engine to charge its battery, because in the desert it would be difficult to find a charging station.
The recharge
The Audi RS Q e-tron’s battery is recharged while driving with power from the power converter and a third MGU unit, which in this case acts as a generator. Algorithms have been designed and programmed to maintain the battery charge level within defined ranges based on energy demand. The power of the motor-generators installed on the front and rear axles is limited to a maximum of 288 kW, to comply with the regulations. However, the power converter can only provide a maximum charging power of 220 kW. Therefore, only in extreme cases, consumption is slightly higher than the power generation capacity.
The Audi Q4 e-tron and Q4 Sportback e-tron can be charged with different powers depending on the battery, using alternating current (AC) and direct current (DC). The larger capacity battery allows charging with a power of up to 11 kW using alternating current, and up to 125 kW (HPC high power charging) with direct current. With high power charging and in ideal conditions, you can go from 5 to 80 percent of battery capacity in just 38 minutes, and 10 minutes are enough to recover about 130 km of autonomy 130 km.
energy feedback
MGU units installed on the front and rear axles of the Audi RS Q e-tron can convert the rotational movement of the wheels into electrical energy. And to this is added the energy recovered by the intelligent braking system (IBS), which combines hydraulic braking with regenerative electric braking.
In the Audi Q4 e-tron and Q4 Sportback e-tron, energy recovery can be regulated through the driving programs and with the paddles on the steering wheel, which allow the driver to manually select three different levels of retention. When braking, in most daily driving situations recovery is done only by the electric motor of the rear axle. The quattro versions can electrically achieve a deceleration of 0.3 g, which is equivalent to a recovery capacity of up to 145 kW. The system only activates the hydraulic wheel brakes if further deceleration is required.
thermal management
The Audi RS Q e-tron has a sophisticated cooling system to dissipate heat in demanding desert conditions. For this, it has six different cooling circuits: low temperature for the high voltage battery (HVB), low temperature for the motor-generator units (MGU), cooling circuits for the power steering and lifting jacks, air conditioning refrigeration, and high temperature circuits for refrigerant and charge air.
In compact electric SUVs, the thermal management system is not only responsible for dissipating heat, but also for heating the system when the outside temperature is low. It consists of two cooling circuits. One of them controls the temperature of the electric motors, their power electronics, the charger installed on board and the DC/DC transformer, which connects the high-voltage electrical system with the 12V one. This medium-temperature circuit is connected to a low temperature one that only cools the traction battery.
Driving
The Audi RS Q e-tron and the 50 e-tron quattro versions of the Audi Q4 e-tron and Q4 Sportback e-tron benefit from the advantages of electric drive, automatic transmission and four-wheel drive. In both cases they boast a balanced character, thanks to their low center of gravity and the even distribution of the load between the axles due to the low and central location of the propulsion system components.
The Audi RS Q e-tron only needs a transmission with a single forward gear. As in the brand’s electric vehicles, there is no mechanical connection between the front and rear axles. Audi-developed software distributes the quattro’s torque between the axles, serving as a freely configurable virtual center differential, which has the positive side effect of saving weight and space that the axles would have required. transmission and a mechanical differential.
In street models, electric propulsion adapts to any request from the driver, providing a progressive, powerful and consistent thrust, and a quick throttle response. In the competition car, the way this type of engine delivers the torque increases the traction of the tires and will be a great ally in the Dakar arena.
control system
With its control and handling concept, the Audi RS Q e-tron redistributes various roles between driver and front passenger. There are eight buttons on the steering wheel, located directly in front of the driver. Behind the steering wheel is a screen that provides information on tire pressure, selected direction of travel, current speed and various alerts. Two small displays installed above and towards the windshield work as “repeaters” and provide essential information in the field of vision: the direction indicated by the compass is shown on the left, while the speed is shown on the right. A screen located right in the center of the dashboard offers information on tire pressure, brake distribution, brake-by-wire and many other functions. The information is highlighted in green while the different systems are working correctly, or in red when an error occurs. Below this screen is a switch panel whose individual keys react sensitively to touch with a pressure point. In order to orient themselves in the terrain and, at the same time, maintain the prescribed route, the co-pilots have to consult the screens of two tablets.
The cockpit of the Q4 e-tron and Q4 Sportback e-tron offers a design…
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