Petrol engines are changing dramatically. You’ll have heard of the phrase ‘downsizing’ and most major manufacturers are shrinking their regular gasoline engines to trim emissions and fuel consumption – while employing new tech to keep up the horsepower and torque outputs.
This is the holy grail for engineers: maintain the power and performance of the existing big capacity engines we’ve become wedded to, but in a smaller, more economical package. How? By forced induction, clever valve timing and new, more efficient ways of managing fuel injection.
Downsizing: sounds too good to be true!
They are many competing demands of modern petrol engines. Here’s how they do it. Take Ford’s new Ecoboost engine family. They claim that the new 1.6 Ecoboost engine for the Focus class has the performance of a contemporary 2.0-litre petrol but the fuel economy and emissions of a much smaller motor. There will also be a 2.0-litre Ecoboost engine primarily aimed at the Mondeo segment to replace larger lumps (farewell the 2.5 five-pot) and a smaller, unspecified engine small engine for the Fiesta/Ka class, most likely with a capacity of between 1.0 and 1.2 litres.
Make no mistake, those badges on car boots are going to tumble dramatically, ending years of corporate car park one-upmanship.
>> Click ‘Next’ below to read about the new technology that will make petrol engines cleaner and greener
Turbocharging engines of the future
Ford will turbocharge its new Ecoboost engines, which will be sold in the US first, followed by Europe and – eventually – the rest of the world. The latest blowers are smaller and cleverer, their low inertia allowing them to spin at more than 200,000rpm. It helps pump air into the engine at lower speeds, so a juicy wave of torque is available from just 1500rpm.
Everyone’s at it. Volkswagen has set a lead here with its Twincharger engines – in the Golf, it adds a supercharger and turbocharger to a 1.4 engine with outputs as high as 168bhp. Not so long ago, anything with a specific power output of 100bhp per litre would have been found on a racetrack. Turbocharging is everywhere – even BMW is turning to forced induction and the next M5 is set to be a V8 turbo in place of the high-revving V10.
Direct injection: here to stay
Meanwhile, fuel will increasingly be injected into these new, smaller engines by direct injection. It uses technology seen previously in diesels, with incredibly precise metering and droplets of petrol of just 0.02mm (one fifth the width of a human hair) fed into the cylinders at pressures of up to 200 bar.
Direct injection also has the effect of charge cooling, bringing denser air for combustion that’s richer in oxygen. Result? More power, more efficient burning. Downsides? The injection equipment is specialist and very expensive.
>> Click ‘Next’ below to read about the new technology that will make petrol engines cleaner and greener
Valvegear: what to expect
Clever operation of the intake and exhaust valves will be magnified in the new, downsized age. By carefully controlling the valve timing manufacturers will exaggerate the scavenging effect to increase air flow through the engine and bolster low-end torque.
Valves will increasingly be programmed to open and close for carefully controlled times and duration, depending on load, throttle and how warm the engine is. Every single variable will have an effect.
Reducing friction and losses
Car manufacturers and oil producers are working hard to reduce friction inside engines and oils, and you can expect more systems to bring engines up to operating temperature quickly. Clever thermal management systems will recapture energy from the exhaust, micro-hybrids will claw back energy wasted during braking and stop-start systems will stymie every last drop of fuel that’s not spent on forward propulsion.
Ferrari’s even taken to super-polishing some components to cut the friction as low as possible.
>> Click ‘Next’ below to read about the new technology that will make petrol engines cleaner and greener
Petrol engines: the outlook
‘Conventional petrol and diesel engines will dominate the market for at least the next decade,’ vows Ford of Europe’s powertrain development manager Andrew Fraser. ‘Forget all the talk about hybrids – a lot of it is expensive propaganda. Our strategy is to make a small difference to a lot of people. If we can make every Focus in the country 1% more economical, it’ll save more fuel than every single hybrid in the UK.’
The petrol engine of the future: 70g/km, 94mpg
Bosch, the world’s biggest automotive supplier, points out that a modern petrol car can drive 40 times further than an electric car per kilogramme of energy stored. And it has great plans for the long-term survival of petrol engines.
‘We aim for a 29% reduction in fuel consumption by 2015,’ says Dr Rolf Leonhard, executive vice president of engineering. ‘This will involve downsizing the engine to 1.1 litres without compromising power and torque thanks to turbocharger boost pressure increasing from 1.8 to about 2.4 bar. And by around 2015 we’ll see the first series application of the new HCCI homogenous charge compression ignition engines, potentially reducing gasoline consumption by a further 2-3%.’
Seems like there’s life in the old petrol engine yet.
>> Click ‘Add your comment’ below and let us know what you think of the first instalment of CAR’s Tomorrow’s world series
Petrol engines: the outlook
‘Conventional petrol and diesel engines will dominate the market for at least the next decade,’ vows Ford of Europe’s powertrain development manager Andrew Fraser. ‘Forget all the talk about hybrids – a lot of it is expensive propaganda. Our strategy is to make a small difference to a lot of people. If we can make every Focus in the country 1% more economical, it’ll save more fuel than every single hybrid in the UK.’
The petrol engine of the future: 70g/km, 94mpg
Bosch, the world’s biggest automotive supplier, points out that a modern petrol car can drive 40 times further than an electric car per kilogramme of energy stored. And it has great plans for the long-term survival of petrol engines.
‘We aim for a 29% reduction in fuel consumption by 2015,’ says Dr Rolf Leonhard, executive vice president of engineering. ‘This will involve downsizing the engine to 1.1 litres without compromising power and torque thanks to turbocharger boost pressure increasing from 1.8 to about 2.4 bar. And by around 2015 we’ll see the first series application of the new HCCI homogenous charge compression ignition engines, potentially reducing gasoline consumption by a further 2-3%.’
Seems like there’s life in the old petrol engine yet.
>> Click ‘Add your comment’ below and let us know what you think of the first instalment of CAR’s Tomorrow’s world series