Hopper cooling

Cooling water is heated by the engine and evaporates from the surface of the hopper as steam.

[2] Internal combustion engines are rather inefficient and require cooling to dispose of the waste heat they generate when running.

Water-cooled engines remove this heat from around the cylinder head by surrounding it with a water jacket.

This is both an advantage and a disadvantage: it maintains a low operating temperature, helping to preserve the fragile piston rings and exhaust valves of these early engines.

To avoid frost damage, the hopper could be drained easily through a large brass tap.

As the cooling water evaporated continuously when running, no anti-freeze or anti-corrosion additives were used.

A handful of engines, now largely diesels, retained hopper cooling into the 21st century.

Single cylinder horizontal diesel engines were built in India and China and were briefly imported to the West around 2000, but were outlawed by emission control regulations.

Evaporative or steam cooling was used experimentally for high-powered aircraft engines in the 1930s, notably the Rolls-Royce Goshawk.

Aircraft evaporative cooling, like radiator systems, used a pumped closed-loop for the coolant, without loss.