Hybrid strategy and predictive efficiency assistant
The new Audi Q7 e-tron quattro* is an out-and-out know-it-all – especially when it comes to predictive energy management. Even three-time Le-Mans winner and hybrid professional Marcel Fässler is surprised.
“That was the signal, I just felt it.” Marcel Fässler smiles and lifts his foot off the gas. The Audi Q7 e-tron quattro carries on up the hill with gusto. “But why here, it’s uphill?” Seconds later, he reaches the crest, the road continues on a slight downhill course. Then a roundabout comes into sight, less than 200 meters away, just after the city limits. “That’s why,” says engineer Philipp Seyberth, also smiling.
The scene obviously needs some explanation: The signal that race driver Marcel Fässler got from the new SUV with plug-in hybrid drive was a slight pulsing of the gas pedal against his right foot. He should recognize that as a request to lift off the gas and let the car “glide”, i.e. coast along without any driving force. Why? Because the Q7 e-tron quattro knows perfectly well it has more than enough kinetic energy to reach the roundabout over the crest of the hill, and that no further drive energy is therefore necessary. Predictive means being able to look ahead and forecast, and the artificial intelligence of a Q7 e-tron quattro can forecast a whole lot – at least when comes to the best use of energy in a car.
Customers will make a conscious
decision to buy the e-tron.
And they will be equally conscientious
when they use it.
Project Management Hybrid Functions
In the case of the new e-tron model, that energy comes not only from the diesel fuel that feeds the 190 kW (258 hp) 3.0 TDI, but also from the lithium-ion battery. Its 17.3 kWh capacity is ideally charged with electricity from renewable sources. The battery pack in the rear of the SUV is enough for more than 50 kilometers of battery-electric driving – theoretically. In practice, it’s very often sufficient for a bit more, thanks to the amazingly smart hybrid operating strategies. As project manager for the hybrid functions in the Q7, Philipp Seyberth spent the last few years working on these, along with around 20 co-workers. And the team came up with a great many features that make this car unique right now among the competition.
The small village of Aranzueque, northeast of the Spanish capital Madrid, is now behind us and Marcel Fässler accelerates the Q7 with considerable oomph, using only the 350 newton meters of its electric motor. “Our active drive pedal uses a slight pressure point to signal the edge of the operating envelope of the electric drive,” explains Seyberth. “If you push on through that, the TDI cuts in,” he continues. The V6 is so well insulated against noise and vibration, the interaction of the two drives so natural, that the change is virtually imperceptible. If the driver selects the S shift program for the eight-speed automatic, the engine and electric motor work in unison at all times, with the reward being acceleration from zero to 100 km/h in just 6.2 seconds. “It moves pretty fast,” is the succinct comment from the racing driver, although the smile on his lips says it all.
Battery summary – green: EV 66,6 %, yellow: Hybrid 66,6 %, purple: Hold 18,2 %
Hybrid modes used in the Audi Q7 e-tron quattro – green: EV, yellow: Hybrid, purple: Battery Hold
Drive modes used in the Audi Q7 e-tron quattro – green: purely electric, red: combustion engine in use
Fässler and Seyberth have been traveling through the hilly Castile countryside for a good 50 kilometers. This morning’s tour is almost double that distance. Philipp Seyberth entered it into the navigation system and the digital assistant in the background calculated the optimum operating strategy using GPS files that are now incredibly detailed. The software uses an enormous number of parameters – one of them being that most of the electrical energy stored in the battery should be used up by the time the destination is reached. The battery can then be recharged at the wall. Another premise is to drive on battery power alone through built-up areas. If a larger city lies at the end of the route, the system plans for this accordingly.
The Audi works driver and three-time Le-Mans winner Marcel Fässler is extremely familiar with the term “hybrid strategy” from his regular ride, the Audi R18 e-tron quattro. “The regulations specify precisely how much energy we are permitted to use per lap, down to the last gram. We’re absolutely not allowed to exceed them, or else we’ll be penalized.” This notwithstanding, the driver has to achieve maximum performance lap after lap, has to make his way through the traffic on the track and battle hardfought duels – always with an eye on the “consumption gauge”. “Obviously, in the course of any one lap, you often go above the allowance,” says Fässler, which means savings then have to be made. In the first years with the hybrid car, the driver lifted off a little earlier. Now, the hybrid system controls such gliding phases on its own, mostly on high-speed sections of the track and just before the braking and recuperation point, in order to lose as little time as possible. “It sometimes doesn’t even take 100 meters until we’re back in the black.”
The first section this morning was highway, where the Audi Q7 e-tron used the engine almost the whole time – obviously with gliding and recuperation phases wherever possible. The predictive efficiency assistant opted for the “battery hold” hybrid mode. This means that no energy is drawn from the battery, reserving it for subsequent sections of the route. We are now heading along small, winding country roads at speeds of 70 to 90 km/h. The intelligent assistant in the background is convinced the Q7 will manage the rest of the route on its remaining reserves of electrical energy – so the SUV is now driving in “electric vehicle mode” with zero emissions. Almost. On a couple of longer uphill stretches, the hybrid strategy in the control unit calls on the help of the TDI. This is also the case during one or two acceleration phases coming out of builtup areas or pulling away from stoplights, where Mr.Race Driver chooses to ignore the pressure point in the pedal, wanting to feel a bit more of the 275 kW (373 hp) maximum system power.
Marcel Fässler is fascinated by how smoothly the highly complex interaction of all the Q7’s technology components actually runs. “You have to listen really carefully to notice when the TDI cuts in.” This applies even more to the so-called blending of the brakes. As much as possible, the e- tron brakes with its electric motor and stores the recuperated energy in the battery. The wheel brakes kick in only when there is a need for really heavy braking. The Q7’s driver senses absolutely none of this. “The race car runs on the same principle, just that the recuperation and braking phases are shorter but more intense.”
The drive management is
extremely smooth. You hardly feel the
engine and motor switching
on and off. But it delivers real performance, too.
You can really push on if you want to.
Audi Works Driver
Friendly support – With its smart drive control and multi-faceted assistance systems, the Audi Q7 e-tron quattro is a first-class, innovative technology package.
Electric fuel station – Marcel Fässler tests the charging connection. His Le Mans race car is obviously not charged via cable. It draws electrical energy from recuperation alone.
When it comes to carbon footprints these days, hundredths matter. However, it goes without saying that, even with a drive system as sophisticated as that of the Q7 e-tron, a major efficiency factor is the driver’s right foot. Nevertheless, the extensive package of assistants does its absolute utmost to help. The ACC adaptive cruise control, for instance, even has a predictive function. Driving speed is calculated based on route data. The Q7 knows the course of the road and the radius of the bends from the map, while the camera “reads” traffic and town signage with a high degree of precision. All the driver has to do is steer. “I don’t think I’ve ever had such a relaxed drive,” smiles Fässler as he tests this function, before switching back into “manual” mode. At the end of the day, he wants to feel the full performance of the Q7, with its sophisticated running gear.
And how does the efficiency assistant calculate if no navigation destination has been entered, meaning it doesn’t know the planned route? “Then is restricts itself to the next three or four kilometers along the road,” says Seyberth. “Strategic energy planning isn’t possible in this situation, but good recommendations for the next gliding and recuperation phases can certainly be made over that distance, based on upcoming gradients.”
After almost one-and-a-half hours, we are approaching the endpoint of our tour. The Q7 e-tron is driving on battery power alone, yet still manages to keep pace with the sometimes extremely hectic traffic on the outskirts of Madrid. “You’re more attentive driving this than a conventional car,” observes the Le Mans winner. The power display in the fully digital virtual cockpit, the energy-flow readouts in the MMI display and the active drive pedal are, of course, supplying new and additional information. And the efficiency recommendations are most effective when the person at the wheel actually follows them. “Customers will make a conscious decision to buy the e-tron,” says Seyberth with conviction, continuing, “And they will be equally conscientious when they use it.”
The record for this little morning trip shows how excellently the Q7 e-tron functions in practice. Philipp Seyberth had installed a data logger from his development stores to track precisely all 95.9 kilometers. Marcel Fässler drove on battery power alone for two thirds of the way, give-or-take exactly 66 kilometers. During that time, the battery was not charged by the TDI, with the high range ultimately achieved through the recuperation phases alone. And the consumption of the TDI, factored up to 100 kilometers, stands at just 3.9 liters. This is a fantastic – and absolutely realistic – figure for an SUV of this performance class with permanent all-wheel drive. “Of course it is. I stuck to the efficiency assistant’s recommendations,” says Fässler with a smile. “Most of the time, at least.”
* Audi Q7 e-tron 3.0 TDI quattro:
Combined fuel consumption in l/100 km: 1.8
Combined CO2 emissions in g/km: 48