F1 engines: From ICE to MGU-K
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Bob McMurray explains the complexities of the F1 engine
Remember the days when racing cars failed on track, with flames, smoke and shrapnel erupting in a large cloud in their wake? Puddles of oil as witness to something having gone just a tad wrong?
Drivers would trudge disconsolately back to the pits, helmet slung loosely in hand and go into the garage to talk to the — and shortly after, when the journos of the day demanded an answer as to the cause of the spectacular on track eruption of volcanic proportions, the various engine manufacturer representatives would bravely front the press and announce that it was an “electrical failure”.
Well, sort of true, in that an internal part of the engine, usually a connecting rod of some sort, exited the high revving engine at a point not normally allowed for the purpose and flew into the alternator, which exploded and consequently stopped the electrical charge to the spark plug, which then caused the engine to stop.
Engine failure? No sir. Electrical failure it was!
Those days are gone in top-level motorsport. Now we have multiple hybrid, computer controlled “power units” (not plain engines, of course) with high-tech turbos rotating in excess of 100,000rpm with six various elements that go to making the “power unit” as a whole.
So, what do all these elements do?
This is one of those subjects on which most people who are into the sport will nod sagely and assure all and sundry that they understand all the bits that club together to make a Formula 1 car go forward.
So the following is not for them, but for those people who think they know what is happening but are not too sure.
An idiot’s guide follows. And I know it is an idiot’s guide, because I wrote it.
Six basic bits
There are basically six bits of kit that go to make the whole.
The first is the “ICE” (the internal combustion engine).
This is the bit that most closely resembles the beating heart of the old 1.6-litre Toyota Corolla in the garage.
It has pistons that go up and down and make a bang when fed a mixture of fuel and air, which is then ignited in a cylinder. That operation in turn makes a crankshaft go around, which then turns a shaft which eventually, through a complicated series of gears, makes the wheels turn around.
Then we get to the “TC” (the turbocharger).
This magic thing is almost as old as the motor car itself, having been patented in 1905. It is now a favourite for every type of engine from boy racers driving whistling and backfiring boom boxes to aeroplane engines, from 2000-tonne ship engines to 125cc motorcycles, petrol or diesel.
This device takes the exhaust gases produced by the ICE to turn a fan, which sucks fresh air in, then pushes that air into the ICE (engine) cylinders under pressure and makes a bigger bang, which means more power.
So far, so simple. But now we come to the MGU-K (the motor generator unit-kinetic).
When you brake in a road car, the discs (rotors) get hot as they absorb the energy of the vehicle braking. Obviously, it’s the same — with a huge amount more energy — in a Formula 1 car, but the difference is that this braking energy, called kinetic energy, is then collected by a form of generator around the braking system and sent to the ES, (the energy store — or batteries to you and me).
Thermal energy recovery
On then to the MGU-H (motor generator — heat) a thermal energy recovery system, which collects energy in the form of heat from the TC (turbo) and ICE (engine) exhaust gases and converts that to electrical energy, which also then flows on to the hungry little battery.
All these bits hum along in harmony, but in solo performances.
Something has to manage all this lot, so in comes the orchestra’s conductors, the CE (control electronics) and the ECU (electronic control unit) and a wheelbarrow full of wiring and software to connect it all together and hopefully make sense of it all.
What we end up with is a huge amount of energy being collected each lap from these various elements and stored in the battery for use when needed. It is needed at various points during each lap so you have times when the car is “harvesting” this energy — a red light flashes at the rear of the car to make following drivers aware the car in front may not be on full power; that has to happen for around 17 seconds per lap to get maximum charge — and then times when the battery is pushing the power out.
This electrical power output feeds back to the driven wheels through the MGU-K (versatile thing this) and can boost the available power to the car by around 120kW (160hp) for approximately 30 seconds per lap. A standard road car battery produces just 1kW.
Although engine manufacturers rarely release actual power unit figures, the estimate for the beginning of the 2016 season was about 670kW (900hp plus) with 745kW (1000hp) on the horizon.
Sometimes a Formula 1 car stops before the electrical energy has been safely dispersed, so the wearing of safety gloves is needed to avoid a shock from the highly conductive carbon fibre.
In short, the ICU burns the fuel and, boosted by the TC, makes the power, then the MGU-K and MGU-H harvest the heat, convert it to electrical energy then pass that on to the ES, which in turn feeds it back in the form of extra power through the MGU-K, while the CE and ECU keep all the bits singing along in harmony.
So nowadays, when a Formula 1 car resembles an old steam engine on the track, it really is likely to be an “electrical” problem.