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Mercedes-AMG HPP awarded Dewar Trophy for PU106A Hybrid F1 Power Unit

The Dewar Trophy was presented to Andy Cowell, Managing Director of HPP, along with members of his project team from Brixworth. Click to enlarge.

The UK’s Royal Automobile Club (RAC) has awarded the prestigious Dewar Trophy, presented for outstanding technical achievement in the automotive industry, to Mercedes-AMG High Performance Powertrains (HPP) for the design of the PU106A Hybrid Formula One Power Unit. (Earlier post.)

The team at HPP was recognized for its development of the most advantageous powertrain within the new Formula One regulations. The aim for 2014 was to raise the engine efficiency from around 29% for the previous normally aspirated 2.4-liter V8 to better than 40% with the new 1.6-liter V6 Hybrid turbo. The successful design, research and teamwork resulted in the Mercedes-Benz PU106A Hybrid Power Unit, which has not only been the dominant powertrain in this first season under the new Formula One rules, but is also arguably among the most thermally efficient gasoline powertrains ever produced, with a claimed thermal efficiency of greater than 40%.

PU106A Hybrid Formula One Power Unit. Click to enlarge.

Previous Formula One regulations have concentrated on a simple mechanical limitation such as engine capacity. The challenge to produce the most effective engine was mainly one of flowing as much fuel and air through that engine as possible; the manufacturer who achieved that could be expected to dominate. This led to very high-revving engines with limited relevance to road cars.

The new regulations specify a maximum fuel flow rate—i.e., the best engine will be the one that obtains the most power from that specified quantity of fuel and thus, for the first time, performance is aligned with thermal efficiency. The best Formula One engine will be the one that converts energy the most efficiently and this has direct relevance to road car powertrains of tomorrow.

A traditional rule of thumb decrees that the conventional gasoline engine achieves efficiency of around one third. In other words, of the energy available in a gallon of gasoline, a third is lost as waste heat, another third disappears out of the exhaust with only the remaining third available for useful work. The new Formula One regulations tackle this challenge head-on, particularly by the use of hybrid systems in the form of electrically controlled turbochargers and brake energy recovery.

In an interview with Motori No Limits in January, Andy Cowell explained:

To achieve the step change in efficiency required in order to maintain performance levels, we have developed technologies that break new ground not just in racing but also in the wider automotive world. When the regulations were written, it was decided to fix aspects such as the engine configuration, bore size and crankshaft center line height, to stop the engineers spending time on areas that we are familiar with but where there’s no efficiency gain to be had. So instead you focus on areas such as the waste energy in the exhaust flow from the Internal Combustion Engine (ICE), where you can put in a turbine to recover some of that energy, use it to drive the compressor and improve the efficiency of the ICE.

Likewise, any excess energy can be put into the battery via an electric motor for use to minimize turbo lag and therefore make the car faster. Equally, we recover kinetic energy under braking, through another electric motor connected to the battery. And having that motor coupled with the ICE allows us to maximize shaft power during acceleration. We have achieved an efficiency gain of over 30%—in other words, we are producing over 30% more power for every unit of fuel consumed compared with last year’s V8 engine.

Daimler won the Dewar Trophy in 1909 for two sleeve-valve engines of 22.8 hp and 34.4 hp respectively, which performed on 132 hours of bench test and 2,000 miles on Brooklands track.

This is Mercedes-Benz’ third award in the 108-year history of the Dewar Trophy; the first was in 1909, and the second in 2009.

For Mercedes-Benz, the association between hybrid technology and motorsport stretches back more than a century to the Mercedes Mixte race car of 1907. This employed a series hybrid drive incorporating a 30 / 55 hp gasoline engine and a dynamo that converted the energy of the engine into electric energy, subsequently supplying power to two wheel hub motors on the rear axle.

102 years later, the Mercedes-Benz KERS Hybrid system powered Lewis Hamilton to the first ever Hybrid Formula One victory at the 2009 Hungarian Grand Prix, and earned the the team at Brixworth (then known as Mercedes-Benz High Performance Engines, or HPE) the second Dewar Trophy.

(During the early development phases of KERS in 2007, the system weighed in at more than 100 kg and worked at a thermal efficiency level of 39%. By the end of the 2012 season the KERS units weighed just 24 kg and were capable of 80% thermal efficiency levels. In other words, Formula One development enabled a twelve-fold increase in power density from KERS systems: the impact of which has filtered down into hybrid systems used by the everyday motorist.)

Ford was awarded the Dewar Trophy in 2012 for the 1.0-liter EcoBoost engine.

In the Dewar Trophy’s 108-year history there have only been 43 recipients, and only four from the Formula One industry. These include; G. A. Vandervell of Vanwall (1958) – winners of the first ever Formula One World Constructors’ Championship; Leonard Pelham Lee of Coventry Climax (1963) – creators of the Climax Formula One engine, which powered three of the first six Constructors’ Championship winners; and Keith Duckworth of Cosworth (1969) – the company behind the DFV engine, which won every race of the Formula One World Championship that season.

Winning the Dewar Trophy is the result of hard and excellent teamwork. Formula 1 is the most intense development laboratory in the world: new technologies are pursued vigorously and quickly, more than in any other development environment worldwide. In the course of this, it is paramount to pay maximum attention to every detail and, at the same time, deliver an integrated high-tech package. This is precisely the strength of Mercedes-Benz. There is a reason why the new S 500 PLUG-IN HYBRID is the first luxury sedan with the performance of a V8 and yet the consumption of a compact vehicle. And this marks only the beginning of our strategic hybrid initiative: by 2017 we will have introduced up to ten new Plug-in Hybrid models on the market.

—Prof. Dr. Thomas Weber, Member of the Board of Management of Daimler AG responsible for Group Research and Mercedes-Benz Cars Development

The Dewar Trophy, which was first awarded in 1906, goes to an outstanding British technical achievement in the automotive field during the preceding year, or one that is known to have reached a significant stage of development, application or utilization during the year. For 2014, entries for the Dewar Trophy were considered in the following categories:

  • Internal combustion engine cycle efficiency improvements
  • Vehicle electronics and electric systems
  • Intelligent transport systems
  • Material developments
  • Safety and sustainability
  • Race car technology


Peter Martin

I am SO PLEASED to see thermal efficiency FINALLY being addressed! We need 48% or greater in all our Petrol powered vehicles.

SWRI did the research on this, they need to apply that re-circulation tech to make this happen in road cars.

Thomas Pedersen

The exhaust turbo driving a generator (also employed in some marine diesel engine systems) is great because it obviates Atkinson/Miller cycles with their low specific output.

Mounting an e-motor on the shaft of a turbo has been the dream of power unit designers for decades, but ridden with technical difficulties. Perhaps the development pace and risk willingness of Formula 1 has cracked the code.

The benefits are manifold; aside from boosting efficiency during steady state, the motor/generator could adjust turbo speed both up and down during gear changes. It could produce power with the gas normally lost in the waste gate and accelerate the turbo during down-shift or at low ICE rpm. It would virtually negate the need for mechanically vulnerable variable guide vanes and similar complicated technologies. The additional motor-driven compressor in Audi's new diesels would likewise make little sense if you could just rev up the main compressor.

The turbo motor/generator is inherently small due to the 100,000 - 300,000 rpm it operates at. It would be a cost effective way of recovering and utilizing quite a lot of energy electrically. Of course, it cannot recover braking energy.

I suppose the application where it makes the most sense is in vehicles that do little breaking and a lot of cruising while being able to utilize the additional electrical output. Long-haul trucks immediately springs to mind. Their turbos also rotate at more 'reasonable' speeds and with less variation in rotational speeds.


Heat is a problem for magnets, but an induction alternator might work. Volvo had an electric supercharger feed a turbo, that gets rid of lag and makes the boost more controlled.

There are lots of uses for a small boosted engine, make it direct inject then it has more power with low end. There is less friction, lower pumping losses, lighter weight, now make that a Miller cycle with FFV hybrid, you might just have something.


As I recall, the TIGERS system used a switched-reluctance generator to get around problems with permanent magnets.

Account Deleted

Mercedes AMG has not revealed all of the secrets of the PU106A. One can only speculate what are some of the components that contribute to its outstanding power and efficiency.
F1Sport.it in April showed a picture that possibly revealed some of these secrets (http://www.f1sport.it/2014/04/20/f1-vi-sveliamo-segreto-v6-mercedes/). It depicts a "ruota libera" or flywheel. This would have an impact on turbo lag, turbo size, and electric generator size.
Marcus Duesmann, former chief of Mercedes-Benz's Formula One engine development had a patent US20070101714 which describes an "exhaust gas turbocharger for an internal combustion engine comprising a compressor and a turbine interconnected by a shaft in a rotationally fixed manner, and an electric machine which can be connected to the exhaust gas turbocharger via a clutch, the exhaust gas turbocharger can be driven at least temporarily by a disk-shaped flywheel rotatably supported on the shaft . . .".
It will be a few years before all of this technology filters down to future road cars, but it should be a very important part of improving auto efficiency.

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