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CPT VTES Electric Supercharger Selected for Two Projects

The VTES unit (inset) and installed in the AVL VW Passat demonstrator. in Click to enlarge.

Controlled Power Technologies’ VTES (Variable Torque Enhancement System) electric supercharger (earlier post) is being incorporated in a project by engine developer AVL (earlier post) and will also feature in the Ricardo-led £3 million (US$5-million) HyBoost program announced by the Technology Strategy Board on 9 September (earlier post). Both projects are seeking to maximize powertrain efficiency at the lowest possible cost.

VTES is an air-cooled Switched Reluctance machine, coupled to power electronics and an optimized radial compressor, that delivers high airflow, pressure and efficiency. The electric supercharger operates independently of engine speed, making it suitable to maintaining vehicle transient performance and driveability. The product is designed for integration into both Otto and Diesel engines to deliver enhanced torque, emissions control and CO2 reduction. VTES is optimized to use the standard 12V vehicle architecture.

When applied to a radically downsized 1.2-liter turbocharged engine, VTES delivers in excess of a 50% increase in torque at engine speeds below 3,000rpm, more than compensating for insufficient power from the exhaust turbine. More than 90% of the available torque is delivered in less than a second. Compared with a 1.6-liter naturally aspirated engine, the downsized engine with electric supercharger reduces the 70-100 km/h (44-63 mph) top gear acceleration time from 18 to 11 seconds.

CPT’s electric supercharger significantly increases an engine’s air charge density over the critical first 10 combustion cycles of a low speed transient. Fitted with a low inertia compressor, the supercharger accelerates from idle to its maximum speed of 70,000 rpm in less than a third of a second enabling even a turbocharged engine to achieve full load torque within one second at very low engine speeds. This fast dynamic response and rapid air boosting enables the system to react instantly to high transient load conditions, delivering up to 25 kW (33 bhp) of additional power at the crankshaft. This is more than enough to compensate for any turbo lag and more cost effective than integrating a 25 kW electric motor into the powertrain since only a 12-volt alternator and battery system is required, according to CPT.

CPT recommends a combination of the highly dynamic electric supercharger in series with a conventional exhaust-driven turbocharger to optimize the overall response of the system, compared to other air charging methods. The VTES technology can also help reduce soot and particulate emissions from diesel engines, particularly when the driver accelerates at low engine revs, which, in turn, creates an opportunity to reduce the size and cost of the diesel particulate filter (DPF).

Our electric supercharger is an ideal enabling technology for the extreme engine downsizing being advocated by European carmakers. The system has been designed to be sufficiently flexible to enable use of a common solution across a wide range of gasoline and diesel engine platforms. It delivers the required economies of scale and complements the micro-hybrid strategy of using the existing 12-volt vehicle architecture as an economic alternative to higher voltage ISG based torque assistance.

—Mark Criddle, CPT senior engineering manager

CPT will showcase VTES at the international supercharging conference held in Dresden 24-25 September 2009. The company says it’s progressing a number of confidential development contracts that will lead to commercial applications, initially for small- and medium-volume production, and will continue to work with the industry’s powertrain developers to verify and validate the benefits of electric superchargers.

Controlled Power Technologies was set up in 2007 as a management buy-in funded by venture capital initially to acquire advanced powertrain technologies from Visteon Corporation and its technology development partner Emerson Corporation.



Another technology that could have been in use for decades to improve ICE performance. An electric turbocharger was a possibilty 50+ years ago.

One could wonder what many thousands well paid mechanical/electrical engineers, working for car/truck manufacturers, have been doing for the last 50+ years.

How many performance enhancing technologies will be incorporated in most ICE in the next 10 years?

A new 50+ mpg or 60+ mpg (or a 100 g/Km CO2 level) CAFE may be required to accellerate the process. Will a single country dare do it?

One could wonder what many thousands well paid mechanical/electrical engineers, working for car/truck manufacturers, have been doing for the last 50+ years.

I'm not so sure about the "well paid" , but for the most part they show up to work and do what Management tells them to do. If you think it was easy to break out of that mold, I remind you of what happened to Preston Tucker.



You have a good point, but in a free country like USA, one could expect much more.... A few Bill Gates etc +++ in the automotive arena could have helped to provoke changes.

Nick Lyons

This wasn't done earlier because efficiency was not a priority. Efficiency was not a priority because gasoline/diesel prices were low and CAFE standards were stagnant for years. The SUV craziness was fueled by cheap gas and the high marginal profits of light trucks. Jimmy Carter called for a new energy paradigm 30 years ago, but for various economic and, ultimately, political reasons, we didn't listen. Now it's catch up time.

The difficulties with improving transportation efficiency are political, not technical. No amount of 'automotive Bill Gates' will change that.


Gates was blessed with extreme, varied abilities, energy, vision, and an IBM that let him own/bundle/distribute their PC operating system.

Auto industry mechanical/electrical engineers(EEs) were lead by GM marketers (not engineers), EV/CARB law crushing, and face(d) the high new vehicle cost-of-entry with federal regulations.

Still, it would be nice to have 4 second:0-60mph/4-seat/1000 mpg(or charge)/$100 vehicles - the sort of gains EEs/programmers give us in computers.



If USA's vehicle efficiency gain is political; and the voting majority wants oversized gas guzzlers; and politicians have to be re-elected; the road to efficent locally built vehicles will be very long.

It will therefore take a very strong national leader to convince the majority that catch up time has arrived.


There was a "Bill Gates" in the automotive industry, it was called Henry Ford... That's about the time when cars stopped being a novelty.


Just goes to prove the auto companies have been without good leadership for decades; else they would have listened to President Carter instead of fighting cafe standards and buying off politicians. Instead of paying engineers to design and to develop new efficient engines, management spent the money on PR, lawyers and politicians, a shameful display of protecting profits instead of innovating and building markets for new products.


Lad sounds right, we had a chance - till the Florida voting chads got us..

Henry Gibson

MITI has had a combination air bearing electric turbo supercharger for a number of years. APT has had a similar one. Hydraulic hybrids will give all the needed starting torque. Reading these pages must give anyone the clue. Big engine plus big torque plus big vehicle equals big profit. I know this, and if someone gave me a F350 used, old and working well, I would keep it and drive it as much as I do my present vehicle. ..HG..

Alex Kovnat

Last summer my wife and I were looking for a good used car for our son, who recently graduated Ohio State University and needed a car to look for a job. We wanted to limit ourselves to no more than 10 grand. A clever used car salesman tried to intrest us in a used, turbocharged VW for a price within our limits.

But I recommended against it. You want to know why? The turbo VW (not Diesel) required premium gasoline to avoid destructive knocking under acceleration. That's what supercharging or turbocharging, at least potentially, leads to. So I worry this novel electric motor driven turbocharger might lead to the same problem.


Sounds like people are confusing promises with reality here.

Even with the todays newly available electronics to control such a device, I am unconvinced it is better to add this expensive gear to a turbocharger rather than just improving the control of the turbocharger.

Roger Pham

I'm surprise there was no mentioning the ability to use the electric motor/generator mechanically connected to a turbocharger for both power boost (for rapid acceleration and torque at low speeds), AND as electrical turbo-compounding during cruise, whereby the energy of the exhaust gas is harvested into electrical energy for the car's electrical loads and any excess electrical power can be fed to the starter/generator/motor unit for additional power to the drive train.

Turbo-compounding is a well-known method for increasing fuel economy of post WWII piston transport aircraft by as much as 15-20%. When the engine is highly downsized, it operates at higher manifold pressures and thus will have more residual energy in the exhaust gas.

Thomas Pedersen

I was at a conference about oil reserves in Washington D.C. 5 years ago. There was a professor, John Heywood, head of MIT's engine department giving a presentation.

He basically said that car companies had more than a dozen almost fully developed fuel-saving techniques sitting idly on their shelves because the market wasn't ready for it. It was just not economical with cheap gas.

So go ahead and blame mechanical engineers (who actually developed and researched those technologies) and the car companies, but please try to remember how you and your friends spent their money on cars 5-10 years ago...

So what about the seemingly slow adaptation of these fuel saving technologies..? Well, car models have a very long lead-time. In order to make these technical marvels so unbelievably cheap, car makers have to have highly specialized tools to build them and these tools have to produces hundreds of thousands of units to be economical. Basically, the economical cars we see today, aside from Prius and Insight, look exactly like the other models, structurally. What has been changed? Maybe low resistance tyres, lower ride height, blanketing off some of the air intake, maybe a new front bumper, aerodynamic underside of the car, higher gearing ratio, new engine software, new battery/alternator and electrical power management, and in extreme cases electrical power steering and A/C drive. Stop'n'go technology can be bought as a kit from Bosch without requiring changes of the engine room layout, which is extremely expensive to implement.

The new VW Golf VI is an example of a car, where the entire design was dictated from the get go - it had to be exactly like the previous model on all the key measurements of the car. It basically has the same chassis.

However, have patience for another 5 years and we will see car makers have a lot more room to maneuver because they are not already locked in by investments made several years ago. I expect to see body shapes with improved aerodynamics. I drive a Golf V and I'm actually a little frustrated that it's too tall. I'm 6 feet tall and I have 5-6'' above my head in the cabin... I don't need that much more space - it's just hurting the aerodynamics of the car. And all the other little tricks will come into play and make a big difference.

This is also why Prof. Heywood did not think the hybrids stood much of a chance - because of their high cost and the numerous relatively cheap technologies available to make ICE cars get MUCH better gas mileage.


There was something very political about the inefficiency of America's vehicle fleet: Remember the SUV tax loophole?

Stan Peterson

This seems like a good technology, but a day late and a dollar short.

For all you auto industry bashers, please realize that your hated Suburban, the very anti-green definition of bad vehicle, achieves 50% better mileage than the most economical car on the road, when CAFE was first measured.

And every other car or truck on the road, no matter the company, does better than the best of 1973. That is a long road to have come, in the competition to combat the monopolistic, oil PRICE crisis, in the relatively short time since then.

Fuel economy has doubled, and then doubled again, to get to where we are today. At the same time the newest cars exceed all toxic emissions requirements; and most newly introduced power trains in them, are producing ZERO Pollution now.

Tremendous advances, with cars offering triple digit economy, and genuine substitutes, requiring little or no oil, are on the verge of being offered for sale.

Please take your complaints back to 1980, when they might have been valid. Complaining about not using today's technology, back before it was invented, is particularly mindless.

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