7 tricks to keep F1 cars fast and fuel-efficient

 作者:霍坍     |      日期:2019-03-06 03:16:01
By Paul Marks (Image: Sutton Images) FORMULA ONE motor racing is all about the noise, the fumes, the gas-guzzling cars that would trash the climate in a heartbeat, were we all to drive them. But not any more… As the 2014 F1 season kicks off this weekend in Melbourne, Australia, the drivers will race machines with far greater relevance to future road cars. One day their fuel-efficient, energy-recovery technologies will make their way into the cars we drive. “The F1 cars will have far greater relevance to road cars, with fuel-efficient, energy-recovery tech” Until now, the F1 spectacle has been all about the power of the engine. The 2013 cars, for instance, were powered by beefy eight-cylinder, 2.4-litre engines and before that they were even more powerful 10-cylinder, 3-litre beasts. This year the engine capacity of F1 cars is dropping to just 1.6 litres – the same as family cars like the world’s bestselling hatchback, the Ford Focus. The idea is to kit out the cars with a small engine of a “road-car relevant” size complete with a clutch of energy recovery techniques. Along with better aerodynamics, these will ensure the engine has both green credentials and the speed the spectacle demands. Jenson Button, former F1 world champion with the Brawn GP team, who now drives for McLaren, is impressed. “The power of the engine is nice. It’s very torquey,” he told New Scientist, referring to the new car’s acceleration. So why the change? Major carmakers like Ford, Honda, Toyota and BMW have dropped out of F1 competition in recent years and Volkswagen-owned Audi has declined to join because they argue that F1 is irrelevant to improving road cars. So F1’s governing body, the FIA, and the sport’s three engine-makers – Renault, Ferrari and Mercedes – have worked out how to realign F1’s rules with the greener aims of mainstream carmakers. They hope that will attract more of the mainstream to F1. The goal is to maximise fuel efficiency. “The automotive industry is focused on fuel consumption and the CO2 emissions it generates. So F1 has turned the rules on their head to align with that,” says Andy Cowell, managing director of Mercedes AMG High Performance Powertrains in Brixworth, UK, which develops F1 engines. “The fundamental challenge now is to convert as much of the chemical energy in the fuel into mechanical energy as efficiently as possible.” FIA’s new rules are tough: the new F1 engine has to be at least 30 per cent more fuel-efficient than last year’s engines. If they are not, some of F1’s multimillionaire drivers risk red faces by not finishing the race. That’s because fuel efficiency is now being enforced by two mechanisms: a maximum fuel flow rate of 100 kilograms per hour, which caps the engine power, and a total race fuel allowance of just 100 kilograms, compared with last season’s 150 kilograms. This means teams have to finish the 305-kilometre race on two-thirds of last season’s fuel allowance. But to keep the spectators happy, they must do so at the same speeds. To make this possible the 1.6-litre engine needs to play a few tricks to recover energy that normally goes to waste. Giving a hint of just how complex the new engine is, Mercedes says on its website: “The engine is no more. Long live the power unit”. The heart of the 2014 power unit is the newly shrunk engine that has also had its maximum rotational speed cut from 18,000 revolutions per minute to a more efficient 15,000 rpm. Then a raft of energy-recovery techniques come in to play (see diagram, below). Since 2009, F1 cars have used a regenerative braking system, like that used in hybrid cars, to charge the car’s 25-kilogram, lithium ion battery. Once a lap the battery can discharge into a motor, giving a 7-second kinetic energy boost to the car’s drive shaft. This Kinetic Energy Recovery System (KERS) comprised a combined motor and generator, but this has now been upgraded and is known as the motor-generator unit-kinetic. In generator mode, the MGU-K can now harvest up to five times as much braking energy as the KERS, at 2 megajoules per lap. As a motor, it can take 4 megajoules of energy from the battery and send it to the engine, equating to an extra 161 horsepower (120 kilowatts) over 30 seconds. The next energy-recovery trick is a novel take on a turbocharger, something that has been used in F1 before but which comes with an extra trick up its sleeve this year. In a standard turbocharger a turbine sits in the hot exhaust gas stream and turns a compressor on the air intake side of the engine. This boosts the power of the engine by pumping higher pressure air into the firing cylinders. In the new turbocharger, nothing gets wasted. Once the exhaust gas pressure pushes the compressor in the air intake to 100,000 rpm any extra energy from the turbocharger’s turbine is harvested to turn a device, called the motor-generator unit-heat, or MGU-H. This can charge the car’s battery still more or dump energy into the MGU-K to send to the drivetrain to give the driver an extra boost. This means it uses less fuel for more power. All of this, in pre-season testing in Spain and Bahrain at least, seems to supply the necessary efficiency gains. “We are producing over 30 per cent more power for every unit of fuel consumed compared with last year’s V8 engine,” says Cowell. “We are producing over 30 per cent more power for every unit of fuel consumed” These changes should make life easier for the drivers too as they do not have to think about activating the kinetic and heat recovery systems – jointly known as the Energy Recovery System (ERS) – as they did with KERS in previous years. Smart electronics make sure it is all available through the throttle: if the energy is available from the engine or the battery they can have it on demand. Similarly, harvesting braking energy to charge the battery is now automatic, too. The identical electronic control units in F1 cars are made under FIA rules by McLaren Applied Technologies (MAT) of Woking, UK – a company kept strictly separate from the firm’s McLaren F1 racing team, for the sake of fairness. The control units choreograph everything from throttle control down to changing the gears. Their software has been completely rewritten for the new energy-recovering turbos, says MAT vice-president Peter van Manen. “In terms of road relevance, the whole concept of recovering energy from the exhaust is very exciting because half the energy of a road car is lost as heat through the tailpipe,” Van Manen says. “Being able to recover some of that could have a big impact on carbon emissions and fuel economy.” The true test will be the reliability of the complex turbo engines with all their electric add-ons – and the reaction of the F1 fans to the engine sound, starting at the Albert Park Lake Grand Prix Circuit in Melbourne, this weekend. Some diehard fans may be disappointed. “It’s definitely quieter and more melodic,” says one F1 team member who watched trials in Jerez, Spain. Ahead of the race, things were looking good for the driving experience: “Coming out of the corners you have so much torque it’s exciting,” says Button. “I think the positive thing is we have the ERS unit to fill in the gaps. I would say it’s a very drivable engine at this early stage.” Leader: Formula 1 will spearhead greener cars for us all This article appeared in print under the headline “A mean green machine” More on these topics: