 Two-wheeled vehicle engines
Here is the entire powertrain
The demands placed on cooling systems are particularly evident in motorcycle engines. Here, cost pressures are even greater, and a compact design is required. Just look at how little space this four-cylinder
engine block (pictured) takes up, especially in terms of building height.
When you think of particularly compact and cost-effective engines, two-stroke engines immediately come to mind. They are difficult candidates for cooling because, for example, an ignition cycle per crankshaft
revolution generates even more heat.
Two-stroke engines are also harder to control in terms of noise. Depending on the type of rinsing type, there has also been a very uneven distribution of mass in the history of the automobile, for example on the
piston. Even a cylinder with different openings on different sides tends to deformation when subjected to intense heat.
On motorcycles, air cooling often goes hand in hand with wind cooling. In this context, air baffles tend to be counterproductive, as, among other disadvantages, they also impede heat radiation. An exception
would be a dedicated air duct to the cylinder covers for high speeds and the associated engine load.
Is it any wonder that, especially as emissions regulations become stricter, the technologies used in four-wheeled vehicles are gradually being adopted? Thus, for instance, with models such as the Zündapp KS
50 or Hercules Ultra, two-stroke moped engines of the simplest liquid-cooled design appeared, yet ones that were, notably, equipped with a pump and thermostatic control.
Of course, the system with 1 bar of overpressure will also be introduced for motorcycles. There's even a small expansion tank. Although, or perhaps precisely because, space is limited, coolers and fans can
be found in all sorts of places; most recently, even one just above the rear wheel.
It’s important not to forget about oil cooling, which is also a particularly effective way to dissipate heat in motorcycles. The picture shows a small oil cooler with pipes protected by metal meshes. As a general
rule, oil cooling systems must be equipped with a thermostatic control to prevent excessive cooling.
Finally, here’s a true specialty of the two-wheeler sector: the complex rear swingarm of a scooter. The engine is mounted at its rear and transmits its torque directly to the rear wheel via a clutch and
transmission, or, more commonly these days, an automatic transmission. This is where the fan blade (arrow) makes sense, because this motor is located under a metal cover and is definitely not exposed to
the airflow.
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