Cooling water for Harley Davidson engine: Twin cooled system

The topic we're going to discuss is the new liquid cooling on American bicycles: in Harley Davidson's big twin engine, liquid cooling has been speculated for many years, and finally arrived in 2014 under the famous Rushmore project.
Due to the emission control reasons (stabilizing the engine temperature is an important factor in this respect), the application of these factors is more and more strict. Brand engineers need to carry out real technical innovation to maintain the classic V-twin system and make it as accurate as possible. Origin.

History of development
An engine converts chemical energy into mechanical energy, which generates a lot of heat in the process. In order for the engine to operate properly, this heat must be controlled in some way to avoid damage to the components. HD engines traditionally use air cooling to provide large aluminum wings for the cylinder and the butt (the hottest part of the engine) to allow air to flow as it circulates with the vehicle. This air reduces the temperature by "stealing" the heat from the engine.

It must be noted that the liquid cooling system installed by Harley Davidson is different from the traditional cooling system in that the liquid cooling system and gun stock are installed in the "wet shirt" of water circulation.

In order to maintain the traditional air-cooled appearance, the xr1200 model from a few years ago was used There, the butt of an internal oil circuit is connected to an external radiator (precisely coordinated) to reduce the operating temperature of the hottest components around the exhaust valve.

"Invisible" solutions
After the Milwaukee plant successfully tested the system, water had to be used instead of oil, and there was almost a liquid cooling system.
But not everything is as simple as it seems. Like the ABS brake system, the challenge is to completely hide the system so as not to affect the traditional aesthetics of the motorcycle.
The solution is to split the heater into two parts and cover it up in the next sink.

A mixture flows through it, consisting of equal amounts of water and coolant, driven by a pressure pump placed in the front of the chassis under the voltage regulator. If the situation requires, a fan installed behind each radiator will be activated.

The filling plug regulates the overall pressure of the system, plus the expansion container, all at the bottom of the right.
The system has a temperature sensor and an automatic thermostat to cut off the rotation of refrigerant to the radiator when the engine is cooling, thus reducing the time required to reach the engine operating temperature. At this time, it is time to turn to the radiator to cool the circuit.

Models and Applications
In addition to the benefits of temperature control for compliance with increasingly stringent regulations, there are other improvements to the liquid cooling system.
One of the reasons is that the heat generated by the engine has been greatly reduced, and the new position of the exhaust pipe has also improved the comfort of passengers.
Another advantage is that the compression of the cylinder can be increased from 9.6 to 10.1, thereby increasing the power of the propellant.

Present and future
At present, the liquid cooling model "twin cooling", known as Moco, is some version of the tourism series. However, in the next few years, the scope of application is likely to gradually expand to more models.

Frank Burgan

#mecanicaharley