FORUMula1.com - F1 Forum

[darwin dali]

ESPNF1:
How an F1 car is more energy efficient than the latest Tesla

Thanks to efficiency gains made under the current set of engine regulations, Lewis Hamilton's Mercedes W07 Hybrid is more energy efficient than the average electric road car.

Orders for the latest Tesla have been skyhigh after a price tag of roughly $35,000 was announced.
News last week that Tesla has received more than 276,000 pre-orders for its new family-sized electric car, underlines the shift in thinking in the automotive industry towards electric vehicles. Yet in a county like the U.S.A. where at least 66 percent of electricity comes from coal- and oil-fired energy stations, with just 13 percent coming from renewables, an F1 car is arguably a greener alternative.

The thermal efficiency of Mercedes' class-leading hybrid F1 engine has now exceeded 45 percent, with 50 percent thermal efficiency a very real target in the next couple of seasons. By contrast, coal and oil power stations achieve thermal efficiency of just 33%, meaning the power used to drive an electric car is likely to be coming from a less efficient source than an F1 engine.

Mercedes technical director Paddy Lowe believes F1 technology could offer a more efficient future for the automotive industry, but says the message is not being spread widely enough.

"Electric cars are seen as green and the solution to all carbon emissions, but they are absolutely not," Lowe told ESPN. "It all depends where you get the electricity from and in a typical country with a regular profile of electricity generation, a Formula One car is massively more efficient than any electric car being charged from a power plant which is burning hydrocarbons. It is incredible that we've done that, but nobody is really talking about it that much."

The beauty of F1's drive for efficiency is that it is the only way to gain more performance. By limiting the amount of fuel and its flow rate to the engine, the only way to have a more powerful engine is by making better use of the fuel available.

"The really exciting point is that because the regulations drive us to get more efficiency, the only way to get more performance is to be more efficient," Lowe explains. "And while we have already achieved 45 percent, we are not even stopping and so we will probably in two or three years' time achieve 50 percent efficiency. When you bear in mind that road cars have been stuck around 30 percent for the last 50 years that is just mind blowing."

Lowe believes the biggest failing of the current engine regulations, which are still talked down by F1 CEO Bernie Ecclestone, is the sport's inability to convey its successes to the outside world.

"The 2014 changes were all geared around efficiency, an environmental message and a road-relevance message. I think they've been very successful and one of the least successful aspects is how we talk about that and what has been achieved and leverage that as a success story and how that may influence the public and the automotive industry, as it was intended to do.

"We set out with that objective, we achieved it technically, but we haven't gone and harvested the intent, which is a bit strange for me. The technical stories in there are absolutely amazing. We have hybrid engines now that are more than 45% efficient."

Although the latest F1 technology has yet to filter into road cars, the potential for it to do so is realistic, as explained by Mercedes engine boss Andy Cowell.

[darwin dali]

ESPNF1:
How two-cylinder engines and F1 technology could redefine road cars

Formula One technology and very small capacity engines should be the future for road cars, according to Mercedes' F1 engine boss Andy Cowell.

The current F1 engine regulations were designed to promote hybrid technologies and since their introduction manufacturers have improved thermal efficiency from 29 percent to more than 45 percent, meaning more than 45 percent of the potential energy in the fuel is delivered to the crankshaft. Cowell believes those efficiency gains will start to filter down to road cars in the near future, allowing family-sized cars to be powered by small capacity, two-cylinder engines.

Asked what drivetrain he would use if he was designing the next generation of Mercedes C-Class, Cowell came up with a proposal quite different to the brand's current offering of straight fours, V6s and V8s.

"If I get the job of the next C-Class and we can get parts for free -- so somebody doesn't pull the cost out of it without destroying the efficiency -- you would definitely go for a very small capacity engine, tiny, maybe half a litre," he said. "It would be less than three cylinders, down at 400cc -- let's start talking about cc and not litres. So a 400cc, 90-degree, v-twin with 200bhp!"

Cowell's idea of a two-cylinder engine would also be turbocharged much like the current F1 engines, with an F1-style MGU-H to control turbine speeds in order to combat turbo lag. Independent MGU-Ks would also be fitted on the front wheels to harvest energy under braking and provide four wheel drive when necessary under acceleration.

"I hate brake discs getting warm on any vehicle, so it's probably having an electric machine at the front two corners if we are staying rear-wheel drive for a nice driving experience. So one electric machine on the powertrain, two electric machines on the front that have got enough power to absorb over half a G braking.

"You would have a miniaturised version of the F1 assembly to recover energy from the turbine and you would use that when you really want to get away from the traffic lights. So you'd have the front drive motors, four-wheel drive, you'd have the engine pulling you away and then when you want to do your zero emissions around town, you would have used the engine in the suburbs to make sure the battery is full.

"You need a decent battery, efficient power electronics and then it's a question of how much would the engine actually be doing? At that point is it not just a range extender? Is it not that the C-Class has a 400cc, v-twin range extender that sits there and operates at full throttle with around 54% thermal efficiency?"

The MGU-K on an F1 car controls the turbine speed for optimum boost pressure, with any excess energy either harvested and stored in the battery or delivered straight to the crank shaft via the ERS. The biggest difference with an F1 power unit and a road car is the way the driver demands power, as a road car is unlikely to be driven at full throttle on the straights with heavy braking in the corners. Cowell said that would have to be considered on the road car engine design.

"It's the drive cycle aspect of whether the electric machine recovering from the turbine is of merit, because how many of us drive our road cars at full throttle? Not many. And even if we do, it's only for a few seconds. The electric turbo recovering from the turbine needs full throttle, which is then where you are getting into the electric machine doing even more."

Despite a trend for electric cars in recent years, Cowell sees hybrid gasoline engines as the future for journeys outside of cities.

"I think there is a beautiful partnership between high-voltage hybrid systems and internal combustion engines, where they can help each other," he explained. "There is a huge problem with the mass of batteries in pure electric vehicles. Cars need to have low aerodynamic losses and be lightweight [to be efficient], but as soon as you say 'lightweight' and 'electric vehicle' there is a huge conflict. So what you want is a system that recovers all that kinetic energy and a system that uses gasoline because gasoline has great energy density. But you want an engine that converts that at greater than 50% efficiency to useful work.

"If in the future we are all going to be living in cities and close together, then electric cars are fine. But we need to make sure that the electricity comes from an honourable source -- it's very important that we keep an eye on that. What comes out of our three-pin [wall] socket hasn't necessarily come from a great source.

"If it's coming from solar panels on all the buildings then fine, but if it's coming from coal-fired power stations or gas turbines, I don't think it's that honourable. In cities an EV [electric vehicle] with zero emissions is perfect, but as soon as we start doing say 100km or maybe even 80km -- not a big number -- then a hybrid makes more sense."