Anyone know how it worked ? What's a "6 stroke" when it's at home?
Talking of at home, is anyone hereabouts looking after one ? There's supposed to be one in Bath, ex- Brum Museum of Transport, but no-one seems to know where it has got to. Best lead I've had is that a local engine collector is looking after it.
"The Griffin System: In engines of this cycle there are two explosions every three strokes, but since the Griffin engine is double-acting, one impulse is given to the piston every revolution and a half.
The successive stages are: (1) Aspiration of the gas and air mixture. (2) Compression. (3) Ignition, expansion, driving stroke. (4) Exhaust of the burnt gases. (5) Admission of air blast to complete the expulsion of the burnt gases. (6) Exhaust.
Admission and ignition are controlled by a slide valve, and the speed is regulated within small limits by means of a governor, which acts on the gas admission valve placed on the top of the cylinder. As the speed varies the governor suitably advances a triangular wedge, which holds the valve open for a longer or shorter period. Two valves worked by two cams at periods of 1-1/2 revolution serve alternatively for the exhaust from the two sides of the piston. From official tests of a 12 h.p. engine, the consumption is stated to be about 28 cu. ft. of gas per horse-power hour, and for regularity of working the engine was placed in the first class. Considering the six-
-stage system of working, this result is worthy of notice."
".......Samuel Griffin's reasonably successful double-acting engine made at Kilmarnock, Scotland, by Dick, Kerr and Co. By having a combustion chamber on each end of the piston a power impulse was delivered every one and a half revolutions. The "Griffin" was sometimes referred to as a "three-cycle" engine. An opposed, single-acting piston version was also brought out by Dick, Kerr. It had separate cylinders like the Beck, each making one power stroke out of the six. This engine was thought of highly enough to be included in the Society of Arts trials with the Atkinson and Crossley engines. Its performance in gas consumption came out slightly below the other two."