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Jaguar Introduces C-X75 Gas Micro-turbine Extended Range Electric Vehicle Concept

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The C-X75. Click to enlarge.

Jaguar has unveiled the C-X75 concept, an extended range electric vehicle that uses twin gas micro-turbines from Bladon Jets to power two switched reluctance generators from SR Drives. (Earlier post.) Traction is provided by four 145 kW (195 bhp), 400 N·m (295 lb-ft) traction motors at each wheel for total drive power of 580 kW/780 bhp.

The plug-in, electric drive supercar has an all-electric range of 110 km (68 miles) plus a potential top speed of 330 km/h (205 mph), acceleration from 0-100 km/h (62 mph) in 3.4 seconds, and 80-145 km/h (50-90 mph) in 2.3 seconds. Active aerodynamics allow for a simple fuselage section that remains stable at very high speeds. The plug-in will produce 28 grams of CO2 per kilometer on the EU test cycle, according to Jaguar.

The mid-mounted 70 kW (94 bhp) micro gas-turbines can generate a combined 140 kW (188 bhp) to charge the batteries and extend the range of the car to 900 km (560 miles)—or, when in Track mode, provide supplementary power directly to the electric motors. The four electric motors provide torque-vectored, all-wheel drive traction and grip, which Jaguar deems essential in a car that produces 1,600 N·m (1,180 lb-ft) of torque.

The single-speed transmission has a final drive ratio of 3.1:1.

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  Cx75-3
C-X75 powertrain. Click to enlarge.   C-X75 airflow. Click to enlarge.

The driver and passenger are seated ahead of a sealed airbox that houses the micro gas-turbines. The seats are fixed to the bulkhead as in a single-seater racing car, and air to feed the turbines passes smoothly around them via channels in the structure of the body. With the seats anchored in place, the steering wheel, controls, main binnacle and pedal box all adjust towards the driver.

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Micro-turbine genset diagram. Click to enlarge.

Micro-turbines. UK-based Bladon Jets achieved a recent breakthrough in producing the multi-stage axial flow compressors—the technology used on all large gas turbines—on a miniaturized scale and to very high tolerances. This increased the compression and efficiency of micro gas-turbines to the point at which they can be viewed as a realistic power source. Each of the micro gas-turbines weighs just 35 kg and produces 70 kW of power at a constant 80,000 rpm.

Because the exhaust gases form part of the active aerodynamic package, Jaguar has utilized a specialized zirconia-molybdenum coating. This advanced heat-resistant coating is regularly used in Formula One cars and is applied in a plasma spray to the carbon-fiber diffuser to protect it from the exhaust gases.

Turbines offer a number of advantages over a reciprocating piston engine when powering range-extending generators, Jaguar says. With fewer moving parts and air bearings, turbines do not need oil lubrication or water-cooling systems, all of which offers considerable weight-saving benefits. They can also be run on a range of fuels including diesel, biofuels, compressed natural gas and liquid petroleum gas.

Turbines reach their optimum operating speed and temperature in seconds and so can be used in short bursts to top up the batteries without compromising fuel consumption or life-cycle. Coupled to two switched reluctance generators supplied by SR Drives, the turbines operate either in sequence or together, depending on energy needs, to charge the batteries—or provide power directly to the electric motors—as dictated by the propulsion system supervisory system.

Active aerodynamics. Jaguar is already aiming to reduce the drag coefficient of its future models in order to increase fuel efficiency. The C-X75 presented the additional challenge of managing the high volume of air required by the turbines. To achieve this active aerodynamics have been utilized for the first time on a Jaguar.

By opening the front grille and brake cooling vents only when necessary, Jaguar has increased the design’s aerodynamic efficiency. At the rear corners of the car vertical control surfaces automatically engage at higher speeds to direct airflow aft of the rear wheels for increased stability and efficiency.

The carbon-fibre rear diffuser, a crucial element in guiding airflow under the car and creating downforce includes an active airfoil, which is lowered automatically as speed increases. Vanes in the exhaust ports then alter the directional flow of the gases to further increase the effectiveness of the Venturi tunnel.

The C-X75 has a drag coefficient of 0.32 Cd and active downforce created through the use of an underbody Venturi. The underbody Venturi and directional exhaust gas control kept the car as sleek, compact and low as possible while still generating large amounts of grip and downforce. Indeed, the movement of air itself was one of the principal drivers behind many of the design cues that were incorporated into the bodywork.

We wanted to emphasize how the air makes its way not just over the car but is also channelled into the rear airbox. When operating at 80,000 rpm, each gas-turbine requires 35,000 liters of air a minute which means we needed a series of carefully honed intakes.

—Principal designer Matt Beaven

Advanced lightweight aluminium construction techniques provide weight-saving and economy benefits. Additionally, up to 50% of the metal content is recycled.

Batteries. Battery technology is currently the greatest limiting factor in the development of high-performance electric vehicles with a realistic range. Jaguar says its engineers are currently carrying out research with leading battery suppliers into the next generation of power cells in order to find the best compromise between energy and power densities. The batteries used in the C-X75 are of a composition which offers benefits in terms of weight, lifecycle, energy density and safety.

Braking. The C-X75 is fitted with the brakes used on the supercharged XFR which in 2009 became the fastest Jaguar ever, achieving 363 km/h (226 mph) at the Bonneville Salt Flats in Utah. In this application, regenerative braking technology on all four wheels helps recharge the batteries during driving. The 380 mm internally ventilated front discs and 345 mm rears are covered by polished alloy wheels of 21 and 22 inches wrapped in bespoke hand-cut Pirelli rubber measuring 265/30 ZR21 and 365/25 ZR22 front and rear respectively.

Comments

Roger Pham

It is also a matter of physics that any recip genset that can deliver the kind of power like this twin turbine gensets would be five times heavier and would not even fit into this super-mobile.

If I am to shop for the likes of the Ferrari Testarossa, I would shell out $200K for this Jag instead of $300K+ for a high-end Ferrari, and will be laughing all the way to the bank to deposit the extra $100K that I've just saved.
Going to work daily using grid electricity, I will also smile pleasingly everytimes I would pass a gas station, and would even give them a dirty finger at times.

Knowing that these simple turbines will last forever and will not even need routine oil change like a recip, I will be saving even more $$$. Those electrical components will likewise not need any intensive scheduled maintenance like change of spark plug, valve jobs, transmission repairs, and I can even get away without having any brake jobs nor the brake pads for the entire life of the car, if I can restrict myself to an "occasional need for speed!", instead of succumbing to the urge of blasting away from every traffic light. Those exotic recip sport cars break down fairly regularly, and the cost of fixin' em is prohibitive for anyone having to earn wages for a livin'!

Now, folks with only a $100 grands to spare need not despair!
Just tell Elon Musk to take a good look at this Jag, and manage to take out 2/3 of the battery capacity of the Tesla, to replace it with this 35-kg turbine genset, and Voila, you've got yourself a true jetmobile, the envy of every sport-car enthusiasts in your street and even your city. Just to get to listen to the whine of the turbine once in a while, and to smell the burning of the kerosene will be pure pleasure.

kelly

@ UnnaturallyAspirated,

Jag specs. and what Roger Pham notes, including the Tesla modification.

UnnaturallyAspirated

Roger,
Clearly you are a fan of this concept, but I am surprised by your comments. You can't believe that a 140kw recip would not package in this car? This could easily be a 3cyl gasoline, or 4 cylinder diesel @.5L per cylinder. 5X weight difference is probably about right when you consider all the accessories, but even at this delta, what you are talking about is 250 lbs. Sure it isn't negligible, but no ground vehicle will give up 50% BTE for 250 lbs. Weight simply is not that important unless you are airborn.

As for the supposed infinite life that Capstone and Bladon like to talk about with air bearings or gas turbines in general, this is total B.S. My company is one of the highest volume, highest technology air-bearing gas turbine manufacturers and consumers in the world. I can assure you they do wear out. Turbomachinery suffers from cyclic fatigue and airbearings have limited lift off cycles. As we agree, its a matter of physics.

@ Kelly,

Be sure to write Rattan Tata and beg him to put it into production. He championed the Nano and can bring this to life too if he chooses. Left to the marketing, finance, and engineering team, it won't happen because it doesn't have a compelling business proposition.

UA

kelly

" it won't happen because it doesn't have a compelling business proposition." How many $300k cars do, but many father the tech and implementations that will..

UnnaturallyAspirated

Most car manufacturers are in the business of making money, or least they aspire to. Making cool toys happens to be the method that they choose to accomplish their goal. Many of the manufacturers of 300k cars for sale today seem to be doing well enough to stay afloat and bring new products to market regularly, which suggests they have a compelling business case, either as stand alone, or as a flagship brand as part of a larger organization. vehicles without business cases either don't make it to market or go away soon after.

kelly

"Most car manufacturers are in the business of making money.."

Unnat.. this is why, after 75 years, Jaguar still introduced the C-X75 Gas Micro-turbine Electric Vehicle, even, apparently without your written compelling business case.

Roger Pham

Thanks, UA, for giving us an insider's perspective on micro gasturbine technology.
Sometimes emotion overshadow reason, and we can expect future purchasers of this Jaguar C-X75 jetmobile to do so because they will be overwhelmed emotionally, as I am right now!

But, to put matters in perspective again, the latest Ferrari 599 and Ferrari Scaglietti are listed for @ $320K, having 620 bhp, and have an EPA rating of 12 mpg combined. The tamer Ferrari F430 is capable of 490 hp at an "entry level" price of ~200K+, and it has an EPA rating of 13 mpg combined.

Owner of this Jag jetmobile with ~32 mpg on turbine power should be very happy and proud of its green credential. Being a PHEV will give it all kinds of perks in most cities, such as HOV lanes, and special parkings as well as charging receptacles, plus waiving the gas-guzzler tax.

Heck, we may see this Jag C-x75 again in the next James Bond movie. Perhaps Barbara Broccoli has already taken note!

Darius

UnnaturalyAspirated,
Many things you say are true. But technical partnof your estimation is far from truth. If your figure concernig ICE efficiency would be trouth the avearge milege would be no less than 100 MPG or 2 liter/100 km. Those figures are valid for genset application not for direct motion or auto applications. Another technical issue 70 kW one turbine would be far enough instead of having two. The high power need for automobiles lasts very short time. In EV architecture (or EREV) there is always battery reserve for this part of second and can be imediatly compensated next second. Max. continiuos load driving 15 % grade at 90 MPH speed with AC on would be arround 40 kW. There is plan to install 140 kW genset. Too much redunduncy. That looks like marketing point.

Henry Gibson

Rarely does an automobile engine have the high efficiency that it could if it were operated in the most efficient mode; the average efficiency will be well below 25% and perhaps below 10%. The efficiency of transportation also depends on the speed and is much lower at high speeds. UnnaturallyAspirated could also show the difference between the energy required to do a trip at 80 mph and at 40 mph or 55. Electric motors can be 95+ percent efficient but the car operated at 80 mph will be very less efficient. SwitchedReluctance Drives is a UK company and the motors-generators are very efficient and lighter weight than induction motors or permanent magnet motors and can be cheaper and more reliable.

For ordinary automobiles, the NOAX free piston engine could be far cheaper, reliable and efficient, but it is nice to see that there is enough money and wealth for such inovations to be built and tested. The widely expanded use of fossil fuels are the reason for the wealth. Packard could not get its diesel airplane engines accepted in the 1930s and there was not enough money, but now diesel piston engines and "diesel", JET-A, turbine engines are available to fly all sizes of planes. ..HG..

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