Over the two hundred years
since the invention of the Stirling engine, there have been
and various methods developed to vary the speed of the
Some of them rather complicated.
installed a Stirling in a 25ft cabin cruiser called “Jan de
There is even a You Tube
of it. (Wait till minute 3:22)
It's part 2 of a long video – part one is also
very well worth watching
Their method was to vent the
pressurised helium to a reservoir and then pump it back to
engine when required.
It clearly worked, but I would
class it as an “engineer’s solution” which
“ever more complicated engineering”.
UK Stirling group have developed a far simpler method.
pipe, with tap, is used to connect the gas above the piston with
the gas below the piston.
When the tap is partially
opened, the high pressure which would otherwise be used to
the piston, is allowed to escape to the crank case. The
pressure on the piston is reduced.
The power and speed of the
engine is reduced.
When the tap is closed, power is
No need for a pump to rebuild the
the tap is fully opened, the pressure above and below the piston
is no force on the piston. The engine stops.
control of the engine speed, a needle valve is needed.