ALT-2 Engine Configurations on Motorcycles
This article is for all those who want to know the basics about the different types of engine configurations used in modern day multi cylinder motorcycles. I shall summarize the different engine configurations, and their pros/cons:
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1) The Inline Engine:
This type of engine places the cylinders along the width of the motorcycle, in a straight line. (e.g. The Honda CBR 1000 RR, the Yamaha R1)
Pros: This is by far the most popular choice when it comes to performance motorcycles: There's a reason for that. The Inline engine facilitates one single set of valvetrain (camshafts etc.) for the whole engine, thereby reducing weight massively and also improving throttle response manyfolds. Inline engines are also the highest revvers around.
Cons: As we can deduce from the pics, the inline engine can make the motorcycle very wide. current day Jap litrebikes work around this problem by passing the twin spars of the frame over and above the engine than on both sides of it. The inline 6's of yesteryear were seriously wide machines.
2) The Tandem engine:
Here also, the Cylinders are in a straight line, but the difference is that they are not along the width of the motorcycle, but along the length of it.
Pros: The tandem configuration allows the motorcycle to be as narrow and compact as a single.
Cons: The tandem also makes the motorcycle extremely long, and for this reason, tandems are very rare in the motorcycle realm, more seen in lightweight aircrafts.
3) The Transverse V engine:
This is another common engine configuration seen in motorcycles. Here the cylinders(or banks of cylinders) are along the same plane as the length of the motorcycle, and are at an angle. In simpler terms, nothing sticks out from the sides. The 90 degree V twin is also called the L twin. A V four will have 2 cylinders per bank, a V6 ,3 per bank etc.. (e.g. The Ducati 916, the Suzuki TL 1000R).
Pros: An L twin(90 degree) is the most perfectly balanced engine around. The vibes of each cylinder cancel the other one out, thereby making the motorcycle extremely smooth to ride. The V pattern engine also has a very rider friendly power pulse, and provides superior feedback to the rider compared to the "all-or-nothing" approach of the "screamer" inlines. "Growler" inlines attempt at re-creating the V power pulse by altering the firing order.
Cons: In cars, V engines are used to save space. But in bikes, the converse is true. V engines make the motorcycles longer than inline ones. Packaging is a nightmare with V engined motorcycles. Another problem associated with them is the extra weight. each cylinder (bank of cylinders) will have to sport a set of valve train. this also reduces the throttle response. A transverse V4 is very difficult to package, as it is near impossible to get a front biased weight distribution.
4) The Longitudinal V engine:
This format has the cylinders(banks) sticking out from either side of the motorcycle at an angle, and is made most famous by Moto Guzzi. (e.g. The Moto Guzzi Breva).
Pros: The motorcycle can be made really short. None of the length issues associated with transverse V's are applicable here. Extremely characteristic power delivery.
Cons: the cylinders sticking out from either side are ungainly to the eye. Additional mechanical bits are needed to transfer power from the crank to the wheels. Hardly a formula for sportbikes. Ground clearance during cornering is a serious issue.
5) The Flat (boxster) engine:
Tis type of engine has cylinders sticking out of either side of the motorcycle, parallel to the ground. It is made popular by BMW motorcycles. (e.g. The BMW R1200S)
Pros: Massive savings in terms of length again, very torquey, easy access to engine for maintainence.( We can see this in action in the Paris Dakar rally, where Beemers are the fastest to be repaired in the event of a mechanical malfunction).
Cons: Again, everything that was mentioned about the Longitudinal V's are applicable here too.
Phew! That does it for now. There are also some weird stuff like radial engined motorcycles:
But we shall save them for another day.
