Nissan Micra DIG-S

Yeah. One of life's little rules: never buy a French car.

That's not strictly true is it?

The engines you desribe as Atkinson cycle are not true Atkinson cycle engines. The true Atkinson cycle never really worked well and was really invented as a way to avoid breaching the patent on the Otto cycle engine. The engines that are called Atkinsons these days were, I believe, effectively derived from Miller cycle engines with the super charger removed.

Sp you're right in saying that all Miller cycle engines have some form of supercharger, but that doesn't make them Atkinsons with an added supercharger.

The reason that the Miller cycle engine seems to be undergoing a resurgence is that mechanically driven supercharger design has taken leaps forward of late and superchargers themselves are much more efficient than even a few years ago. The result being that the efficiency and performance of the Miller cycle engine has also improved.

Bear in mind however that the Nissan's engine is a long way from being a converntional Miller cycle engine.

As to the styling, we had one of the first one's in the country. It was distracting to have people taking photographs on their camera phones while driving. People forget quite how innovative it was back in 2003, particularly as so many companies have copied elements of the styling since.

Conversly

Driving a small fast RWD car can be very unsettling for a FWD car trying to follow, as their braking areas are different.

Stuff FWD hatches, Chrysler/Talbot knew how to build a hot hatch, 2 models in fact.

Fewer cylinders = Fewer parts = Cheaper to make

Because they've come up with algorithms to dynamically balance an engine without needing balancer shafts, they're cheaper to make.

Also if they can share more parts this saves on tooling costs.

e.g. 1.2 3cylinder and 1.6 4 cylinder, same pistons, rods and associated components.

In automotive, if they can save 10p per car on 500,000 cars they will try to.

3 cylinder Suzuki

Hmm 750 2 stroke triple

The vibrations made by a multi cylinder engine are inherent in it's design, not in the number of cylinders. Funilly enough an inline four cylinder engine is not actually particularly well balanced.

There are two basic ways to make a triple (if we ignore odd things like V3's) one is to have a 180 degree crank shaft, the other is to have a 120 degree crankshaft. Usually a 180 degree crankshaft has pistons 1 and 3 at TDC while 2 is at BDC. This means that the vertical movement of the two pistons is not balanced by the other. This is poor primary balance in the vertical. Try to correct it with weighted crank webs and you have poor balance in the horizontal. Such an engine is hard to balance and manufacturers will often throw in a balance shaft to try to counter the inherent shakes. Four cylinder engines tend to have 1 and 4 at TDC while 2 and 3 are at BDC. This means the pistons vertical accelerations balance each other out. You will notice however that the longtiudinal seperation between the pistons along the crank means you have a rocking couple that is trying to bend the whole engine in the middle.

A smoother three cylinder engine has a 120 degree crank where the crank pins are seperated evenly spaced. This is a much smoother engine as the pistons motions balance each other out. You will notice in the cutaway picture of the engine that number 1 is at BDC, number 3 is at TDC and number two is in the middle of a stroke. It's a 120 degree crank.

The 180 degree engine is cheaper to manufacture. Partly because it's more like a four cylinder engine so things like crank and camshafts are easier to tool for. And partly because ignition and injection systems are easier to setup build. For example you can use the good old wasted spark system between 1 and 3. Try that on a 120 degree crank and you'd be in trouble.

The micra is built here

Unions

Unions and a general apathy towards quality didn't help.