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Saturday, 22 February 2014

The Rise Of The Cool Economy Engine

NISMO president Shoichi Miyatani holding the new Nissan ZEOD RC's engine
This picture's actually photoshopped, but it makes a point about its size
Historically, the coolest version of a car is the one with the biggest engine and the most kit. The best hatch is a hot one, for example, and if you don't have eight cylinders in your executive car then maybe you just aren't executive enough yet. However, we now live in a world that looks up at the sky and frowns, so the keyword for most engineering and design advances in the automotive world these days is "efficiency." Getting the most out of the least. Even Formula 1 has been affected, with the new V6 Turbo hybrid engines that are getting around 700 horsepower out of 1600cc and then boosting that further with electric motors and energy harvesting. As a result, some of the coolest and most advanced cars coming out are actually the ones packing the smallest engines.

Let's start with the one above, which is no bigger (or heavier) than a student's backpack. It's a three-cylinder turbo engine displacing 1500cc, but those aren't interesting numbers. No, seeing as this is about getting the most out of the least, there are two numbers you need to memorise about this engine. The first is that it weighs just 40kg, or 88lbs if you're an imperial sort, which on its own is mightily impressive. To add perspective, the 2400cc V8 Formula 1 engines that have just been retired from service were limited to a minimum weight of 90kg all-up. F1 engines are not simple things, nor are they engineered in a weekend. Or a week. But it gets better. What's the most they got out of this 40kg three-pot engine? 400PS. Yup, four hundred horsepower. This engine actually has a higher power/weight ratio than that of the new V6T engines that Renault can't get to work in their brand new F1 cars!

This mostly-aluminium engine is an impressive feat of engineering, so it deserves an appropriately futuristic chassis to sit in. Enter the Nissan Zero Emissions On Demand Race Car, mercifully shortened to "ZEOD RC." This DeltaWang-based creation takes the hybridisation of racing cars to the next step by being able to run on full electric power only for a short time. Running purely on invisible lightning it can still manage a top speed of 186mph (300km/h), and at Le Mans after the car has run out of petrol, the battery can last for... one lap. OK, so that bit's not so impressive, as it will only do one lap of each 1-hour stint as an EV, but it's a start! Nissan are entering the ZEOD RC as the "Garage 56" entry at the 2014 Le Mans 24 hours, the one grid spot each year for experimental cars that don't play by the GTE/LMP rules (essentially, anything goes as long as it's safe and unlikely to beat the LMP1 cars). The extremely low-drag shape and a weight figure likely under 500kg for the whole car should put it somewhere amongst the LMP2 cars like the 300-horsepower DeltaWing that spawned it.

Keep an eye on that, then. But that's a pure racing car, what about normal stuff? Well that's getting pretty interesting too, actually. Take the Fiat TwinAir engine, a 0.9-litre two-cylinder turbo engine found in the 500, Panda and Punto. Compared to my 1.2-litre four-cylinder engine it's more powerful, lighter, much more efficient and produces quite a lot more torque as well, plus it makes a pleasing 'putter-putter' sound like a weeny Italian city car should.

Then there's the British-engineered Ford 999cc EcoBoost engine. This highly-advanced triple can produce either 100 or 123bhp, the same choice of power figures as the 1.6 non-turbo four-cylinder it replaces. However, while the higher-tune 1.6 makes 117lb/ft of torque, the new 1.0T makes 125lb/ft in its higher tune, which can then be temporarily increased to more significant 148lb/ft when you engage the overboost system, say to overtake or merge onto a motorway/A-road. Thus, a Focus (or Focus-based C-Max) shouldn't feel wanting for pace with this engine. In fact, Ford are even considering putting the 123bhp version into the base model Mondeo (or Fusion in the US). That will be cool just as long as the weight difference isn't too high, as shifting more weight requires more work from the engine and would dent the economy figures.

Those economy figures are as follows: The 100bhp version emits just 109 grams per kilometre (g/km) of CO2, which is very low indeed for a petrol engine, while the 123bhp tune emits 114g/km and can, Ford claims, average 56.5 miles per gallon. By contrast, the 1.6 NA engine can only manage 48mpg, according to the Focus spec sheet. An interesting fact about this new engine is that when the original Focus came out in 1999, it needed a 2.0-litre engine to make 128bhp and could only do 33mpg. This new, equally-powerful 3-cylinder engine is half the capacity. Now that's modern technology at work!

Image from Car. Click to embiggen
But what modern technology? Well, the engine block is so small that the whole thing can sit on a single sheet of A4 paper. Because of this, they decided to make the block out of cheaper cast iron instead of a lighter alloy, because the weight difference is minimal and cast iron transmits less noise. Lightness is always a good thing. Carrying on this Lotus-like fat trimming is the lack of a balancer shaft, which is normally present in three-cylinder engines to make it smoother. Ford decided instead to make the flywheel slightly out of balance to achieve the same effect with less parts and weight, which also saves them money. I'm not entirely sure how this works, but at a guess I'd say that when the engine zigs, the unbalanced (spinning) flywheel zags, and it evens out. Meanwhile, the exhaust manifold and cylinder head casting have been combined together, reducing the exhaust gas temperature by 100°C (partly thanks to the cooling system). That means that the fuel-air mixture doesn't have to get richer when you floor it, which means it uses less fuel. As for the air side of things, the turbo is of a cleverly-simple design. Finally, it has twin variable camshaft timing, uses low friction coatings on some internal components to save more energy and the crankshaft is offset slightly to align more efficiently with the pistons’ connecting rods.

All this translates to a 1-litre engine that can do the job of a 1.6 or 1.8-litre engine from last generation while wasting much less energy and using much less fuel. The amount of thought and engineering that went into the smallest engine available in any Ford is at least as great as what's gone into their biggest engines, certainly within Ford Europe where they only really do 3- and 4-cylinder engines now. So if you've just bought the Ford Fiesta 1.0 EcoBoost that was crossing Ukraine on TopGear last week, don't go thinking you've got a basic, uninteresting car. Not only can Ford do brilliant chassis for your back-road enjoyment, but that engine is that start of something big... and it's all about being small.

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