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Posts Tagged ‘Porsche’

Somebody KERS!

February 14th, 2010 Comments off

Last August, I posed the question, “Who KERS?” in regards to the limited success of the Kinetic Energy Recovery System employed in the 2009 Formula 1 season, and the elimination of the system for 2010.  Well, it turns out that at least one of the systems developed by an F1 team will in fact live on.

As recently described by AutoBlogGreen, Porsche is utilizing the Williams-developed flywheel-based energy storage system in its 911 GT3 R Hybrid.  The 911 GT3 R is the race version of Porsche’s bread-and-butter 911.  The hybrid system leaves the conventional 480-hp flat-6 powering the rear wheels untouched, while adding a pair of 80-hp electric motors to each of the front wheels.

Porsche 911 GT3 R Hybrid

Porsche has always done things a little differently than other automakers, at least with respect to the 911.  Instead of competing in the horsepower wars using 8-, 10- and 12-cylinder engines with massive displacement, they’ve continually developed their horizontally opposed 6-cylinder combined with lightweight (and often exotic) materials to maintain their competitive edge.  Until just over a decade ago, this engine was still air-cooled, in contrast to literally every other automaker’s water-cooled powerplants.  And even now, in a triumph of engineering over physics, Porsche still hangs the motor way out back behind the rear axle.  So it comes as no surprise that they’ve taken the less-traveled path of using a flywheel (instead of a battery) to recovery the energy from braking.

In the simplest terms, the system works by the front-axle motors acting as generators to convert the kinetic energy of the spinning wheels to electrical energy under braking.  The electrical energy is then converted back to kinetic energy at the flywheel (which is essentially another electric motor), as it spins at speeds up to 40,000 rpm.  Under acceleration, the flywheel then acts as a generator, converting the kinetic energy of its spinning mass to electricity, which is routed to the front-wheel motors, where it is converted back to kinetic energy to help power the wheels. (One thing I’ve often wondered in systems like this is – why all the conversions? You want kinetic energy to move the car, and with a flywheel you’ve got a kinetic energy storage system.  Seems like there’d be fewer conversion losses if you could skip the electro-part of the electro-mechanical system, and just connect the flywheel to the drive system by an intelligently activated clutch or viscous coupling.  I’m sure the hybrid system designers out there could give me countless reasons why this wouldn’t work, however.)

And finally, am I a hypocrite because I like this car so much more than the BMW X6 ActiveHybrid, which I criticized here?  Of course not.  BMW has taken a conventional fuel-efficient technology and applied it to a mass-market car solely for performance purposes, with almost no efficiency benefit.  (Plus, the X6 is ugly.)  Porsche, on the other hand, has taken an unproven fuel-efficient technology, and applied it to a limited production race-car as sort of a rolling laboratory to spear-head the development of this new technology, before potentially applying it to its road-going cars.

And although I (like many others) question the feasibility of flywheels as the energy storage solution for mass-market hybrid vehicles, people also once criticized the throwing-a-dart-backwards handling characteristics of the rear-engined 911.  And by most measures, Porsche has been successful with that effort…

Porsche Goes Lithium, Saturn Leaves Orbit

October 8th, 2009 Comments off

Buried in the pages of the November issue of Road & Track is a short description of the 2010 Porsche 911 GT3 RS.  (For those unaware, the 911 is Porsche’s bread-and-butter sports car.  The GT3 version is the ultra-high-performance, race-bred version of the 911.  The RS is the insane, barely-street-legal, over-the-top version of the GT3.  It’s the one I want.)  It’s got all the goodies you’d expect, but one option really sticks out in my mind: a lithium-ion battery to replace to the conventional lead-acid battery, resulting in a 22-pound weight reduction.  Now, this isn’t a hybrid or electric vehicle of any sort.  The battery is used, as it is in any conventional car, to turn the starter and to power the accessories when the car’s not running.  And while racers have used down-sized lead-acid batteries (barely capable of starting the car) for weight savings for quite some time, this is the first time I’m aware of that a manufacturer has offered a Li-ion starter battery.

There are folks that criticize Li-ion batteries as being too unsafe and too expensive to be a real solution to automotive energy storage.  There are even those that suggest lead-acid batteries are more than capable of storing the energy we need in hybrid and electric vehicles, not to mention the starting-duties of internal combustion engine cars.  (I’d agree with respect to starter batteries, but certainly not the other points.)  But now Li-ion has made it’s way into what most would agree would be lead-acid’s territory for the foreseeable future!  Sure, it’s probably an expensive box to check on your GT3 RS order form, and it really is a niche application.  But it may also be a glimpse into the future of automotive batteries.  (Though I do find it ironic that Porsche is offering this option to save 22 pounds – less than 1% of the weight of the vehicle – while they’ve refused to offer weight-saving and arguably more practical options on their GT3 to the North American market in the past, such as carbon-fiber fixed-back racing seats.)

2010 Porsche 911 GT3 RS

2010 Porsche 911 GT3 RS

In other news, it was announced over a week ago (and how did I miss it?!) that the deal whereby Penske would acquire the Saturn brand and sell vehicles under a contract-manufacturing agreement with various automotive OEMs won’t happen happen after all, and the Saturn brand will disappear.  I find this disappointing, simply because it was a new business model in the automotive world, and I was interested to see how it would work out.  Unfortunately, I guess I now have my answer:  not well.

The Great Pumpkin

October 6th, 2009 Comments off

They say the two best days in a guy’s life are when he buys a race car, and when he sells that race car.  (They also say the same thing about boats.  And spouses.  …But this is about cars.)

Great Pumpkin

The Great Pumpkin

I bought the Great Pumpkin – a 1978 Porsche 911SC – about 6 and a half years ago, from its former owner whose life had brought him to the point that he no longer needed a race car.  (Who needs a race car? you might ask.  Well, doesn’t everybody?)  I bought it to replace my ’89 Porsche Carrera, which I totaled at Virginia International Raceway in 2002.  I also bought it to go Porsche Club Racing, which I did fairly successfully for a few years before life dictated that I, too, should pass the Great Pumpkin on to someone else.

Every little boy dreams of owning a Porsche.  …Or at least a fast car.  As a kid in the ’70s and ’80s I had Porsche posters on my bedroom walls, and decided in the late 1990s that I might actually be able to buy one.  The iconic design of the Porsche 911 has endured for nearly 45 years now.  It remained virtually unchanged for its first 25 years, but even the latest iteration is instantly recognizable as directly linked to the original from 1965.  No other car in the world can claim such direct lineage.  And no other car is equally at home on the race track as it is on the street.  (Well, OK, there might be a few others…)

Yesterday, I sold the Great Pumpkin, to a guy in New York who plans to race it in the SCCA.  (Coincidentally, when I met him, we realized we could be long lost brothers – a fact that was pointed out by one random passer-by who noted our similarly disappearing hairlines.)  I hope he enjoys it as much as I have.

They say the best two days in a guys life are when he buys a race car, and when he sells that race car.  But that’s crap.  The day he sells the race car is much worse.

Categories: General, Racing Tags: , ,

Internal Combustion

August 7th, 2009 Comments off

Those who know me, and those who read this blog (yes, both of you) know that I am bullish on powertrain electrification.  The truth is, though, that virtually all of the cars on our roads today have internal combustion engines, and it will be that way for quite some time.  Fortunately, the internal combustion engine has come a long way from where it started, and it still has a long way to go.  And although the average fuel economy of vehicles in the U.S. has stagnated over the past couple o’ decades, the engines themselves have become much more efficient, moving around more and more mass at ever greater speeds without an increase in fuel use.

2010 Porsche 911 GT3

2010 Porsche 911 GT3

Recently, I was reading an article in Panorama (the official magazine of PCA) about the 2010 Porsche 911 GT3, whose 3.8 liter engine makes 435 hp.  That’s  114.6 hp/liter!  Not so long ago, the 100 hp/liter barrier was nearly impossible to breach, without using forced induction, but the GT3 blows right through it.  How did Porsche do it?  Well, for one thing, they rev it up to 8400 rpm, and to keep it from disintegrating when it gets there they use forged pistons, titanium rods, and light-weight tappets to actuate the valves.  They use variable valve timing and lift to optimize both the intake and exhaust valves across all regions of the rev range.  They use a variable intake manifold, again to optimize the timing with which the incoming pulses of air reach the backs of the intake valves at various revs.  They use a high compression ratio of 12.0:1.  The whole process is controlled through a sophisticated engine management system which constantly monitors conditions and precisely adjusts any variable related to combustion.

Of course, many of these tricks aren’t confined to high-end sports cars like the GT3.  Many production cars these days using variable valve timing, and variable intake manifolds are becoming mainstream as well.  Another technology with the GT3 eschews, but which auto makers are employing, is direct-injection of the fuel into the combustion chamber, resulting in more control of the combustion process.

Coming down the pike, we see efficiency improvements through technologies like variable compression ratio, such as that demonstrated by MCE-5; GM’s homogeneous charge compression ignition (HCCI), which combines concepts of both spark-ignition and diesel engines; and Fiat’s MultiAir technology, which very precisely controls the valve timing of each cylinder individually.  Combining these efforts with smaller engines using forced induction, such as Ford’s Ecoboost effort, may yield fuel efficiency improvements that go beyond today’s hybrids.  (And the technology compounds – the use of turbos means the ability to use variable turbine geometry!)

Internal combustion engines these days are a far cry from what they were 30+ years ago, when carburetors used low-pressure air to suck fuel out of a hole, and ignition timing was controlled through the centrifugal force of a couple of weights attached to the distributor.  …It will be a long time before we’re all driving pure electric vehicles.  And let’s face it: even PHEVs (and EREVs) have internal combustion engines.  So, let’s hope the advances continue!

Tesla v. Fisker

July 25th, 2009 Comments off
Fisker Karma Front

Fisker Karma

Fisker Karma

No, this isn’t another post about the legal battles between Tesla and Henrik Fisker, who had a shot at designing Tesla’s all-electric sedan before starting a car company on his own.  (You can find those on countless other websites.)  This is my subjective opinion, a comparison of the Tesla Model S and the Fisker Karma – two high-end, electrified automobiles intended to excite the car-guy as much as the environmentalist.  These two vehicles will be natural competitors once they’re available in 2010/2011.

Let’s start with the Karma, since Fisker intends to start delivering it in mid-2010, about a year and a half ahead of Tesla’s Model S.  The Karma is a plug-in hybrid of the serial variety (meaning its gasoline-powered GM-sourced 4-cylinder engine merely serves to recharge its lithium-ion battery once its electric range of 50 miles has been reached).  Fisker promises acceleration to 60 mph in under 6 seconds, and a top speed of 125 mph.  While the top-speed is slow compared to most sports cars, it’s well above any legal speed here in the U.S., and is a limitation of the electric drivetrain when used with a transmission with a single forward gear.  And while the acceleration is on par with other sports sedans, the Karma doesn’t look like other sports sedans.  It looks exotic, in the vein of Aston Martin or Maserati.  Only something’s not quite right.  It’s hood is a little too long (think Jaguar E-type, only not beautiful).  It looks like it’s wearing braces.  The diamond shaped reverse-lights mimic the diamond shaped vents in the front fascia, and neither is stylistically correct.  And My God, have you seen that interior?  …The Karma wants to be an Aston Martin V8 Vantage – a stunning automobile also designed by Henrik Fisker.  But it comes across as a not-quite-final sketch that should have ended up in the wastebasket.  In any case, it can be yours for just shy of $90,000 (excluding federal tax credits).  We’ll finally get to see one in motion in mid-August.

Tesla Model S

Tesla Model S

Now on to the Tesla Model S.  I have to admit, I was blown away when the Model S was revealed in mid-March.  Like Tesla’s Roadster, the Model S is motivated by an all-electric powertrain, going 0-60 mph in 5.6 seconds with a top-speed of 120 mph – specs which are almost identical to the Karma’s.  The base version will cost just shy of $60,000 (exluding tax credits) and have a 160-mile range (with optional upgrades to 230 or 300 miles).  The lack of an internal combustion engine allows for more space for occupants as well – the Model S claims it can carry 5 adults PLUS two children.  And it looks good.  Damn good.  It’s not quite as exotic as the Karma; instead, it looks like something you might see on the street.  It looks like what the Porsche Panamera should’ve looked like.  It aims to compete with the BMW 5-series, or perhaps the Mercedes S-class, or maybe the Panamera.  And it does it well.  It’s Achilles-heel is the fact that production likely won’t begin until the end of 2011 (despite the fact that we’ve already seen the prototype going out for a test drive).  And for more Model S design eye-candy, check out this video.

I wish both Fisker and Tesla immense success.  But if I had $90k burning a hole in my pocket, I believe I’d wait the extra 18 months and drive home in a Model S (with the 300-mile battery-pack, thank you).

Doppelkupplungsgetriebe

July 5th, 2009 Comments off

I noticed in the mid-1980s, about the time I became of legal driving age, that cars with manual transmissions get slightly better fuel economy than their automatic transmission equivalents.  I was surprised recently to find out that this wasn’t common knowledge.  And I’ve long wondered, what if we all drove stick-shift?  How much fuel would that save, given that nearly 3/4 of the vehicles sold in North America come equipped with automatic transmissions and the associated 1-2mpg penalty?

A friend recently asked me, why are automatics less efficient?  Now, automatic transmissions are one of the most mysterious components on a vehicle to me.  Inside the transmission are a collection of planetary gearsets, clutches, bands, hydraulic pumps, plates, valves, modulators, and pixie dust that make the car go.  All of this is typically heavier than the components of a manual transmission, and uses a portion of the engine output in its operation.  But the thing which enables the automatic transmission to work (besides the pixie dust) is the torque remover converter.  This is the device that provides a fluid coupling between the engine and transmission, and allows your engine to idle while you’re sitting still with your foot on the brake pedal … and which also accounts for some of the efficiency loss in automatics.

A proper manual gearbox is much more straightforward:  You have a clutch which engages/disengages the connection between the engine and the transmission via your left leg, and gears on the input shaft (from the engine) which engage with gears on the output shaft (to your wheels, through a differential).  No pumping losses, inefficent fluid couplings, pixie dust, or other such nonsense.

Green Technology?

Green Technology?

Blurring the line between manuals and automatics, dual clutch transmissions (DCTs) have been introduced to the mass market in recent years.  VW‘s is called DSG (direct shift gearbox); Audi calls it S-tronic; BMW calls theirs DKG, abbreviating the German “doppelkupplungsgetriebe” (literally, double clutch transmission); Porsche‘s is called PDK (Porsche DoppelKupplungsgetriebe).  These are effectively manual transmissions in which a computer does the shifting for you.  (Of course, they also have a manual mode, allowing the driver to be more involved in the process.)  Note, these boxes are vastly different than the “manumatics” of the past, such as Dodge’s “autostick” and Porsche’s “tiptronic,” which are actually planetary gearset, torque converter-based automatics that pretend to let the driver be in charge.  The new gearboxes are both more efficient than traditional automatics, and often even higher performance – faster shifts – than even the best driver-actuated manuals.  This is achieved by essentially encasing two manual transmissions (one for even gears, one for odd) in a single case – hence, the “dual” nature.  By the computer anticipating and preselecting the next gear to be chosen, shift-time is dramatically reduced.

Could these be a replacement for traditional automatics?  In my opinion, YES, and I back that up with an anecdote: A friend of mine recently bought a DSG-equipped VW Jetta.  He told me it was an automatic, for which I belittled him.  Upon seeing it, I realized it was a DSG and informed him of that fact.  He had no idea, even after driving it a few thousand miles.

A recent article in Automative Engineering International (a publication of the Society of Automotive Engineers) mentions that such gearboxes have been around since the early 1980s, but have only recently become commercially viable because of advances in electronics, sensors, and computing power on-board the vehicle.  New technology has enabled better fuel efficiency AND better performance.  …Ain’t technology great?!