From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
2-stroke compression ignition engine seen at the Commercial Motor Transport Exhibition.
| Identifier | ExFiles\Box 179\1\ img091 | |
| Date | 14th November 1931 | |
| FROM E.{Mr Elliott - Chief Engineer} CHP ORIGINAL C. to G.{Mr Griffiths - Chief Accountant / Mr Gnapp} W. H.{Arthur M. Hanbury - Head Complaints} HS.{Lord Ernest Hives - Chair} PH. COMMERCIAL MOTOR TRANSPORT EXHIBITION. 2 STROKE COMPRESSION IGNITION ENGINE. The most interesting exhibit in the way of engines is without doubt the Junkers 6 cyl. ported two stroke comp. ignition shown on the Gilford Motor Co's Stand. In spite of having opposed pistons with 2 sets of crankshafts and con. rods the engine is extremely compact and neat and compares favourably with the more orthodox types, especially when it is remembered that the stroke is 8.25". This is somewhat explained when it is considered that the unit is made up of two small engines of 4.125 stroke and 2.75 bore placed with piston heads only separated by the thickness of the combustion space. Very little was known about the engine on the stand as the example shown was only received shortly before the Show opened. If the output stated of 120 BHP. at 2000 RPM. can be maintained the weight per BHP. should be quite good. The crankshafts, which appear to be fitted with comparatively small flywheels, are coupled together at the end of the block with a line of 4 equal gears, the drive being collected from the second gear from the bottom through a double plate clutch having a divided central driving plate to provide air cooling. The injection pumps arranged in 2 groups of 3 occupy very little space on one side of the cyl. block. On the other side at the rear is a drive for the scavenging blower, this latter unit apparently projecting over the clutch case. I was informed that this engine starts very easily from cold by turning it over with the usual starter motor. The starting and driving torque of the engine would of course be of equivalent smoothness to a 12 cyl. 4 stroke. It would be interesting to know how long the piston rings on the exhaust end will run before gumming up. On the Trojan 2 stroke petrol engine, where the exhaust gas would be relatively hotter, the rings on the exhaust side piston are said to stand remarkably well. (1) | ||