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).
Proposal to experiment with a third valve in an internal combustion engine to address detonation.
| Identifier | ExFiles\Box 1\3\ B001_X 93-page96 | |
| Date | 11th November 1927 | |
| 493 Hs.{Lord Ernest Hives - Chair} Derby. Copies to:- Whr.{Mr Wheeler} London By.{R.W. Bailey - Chief Engineer} Derby E.P. Derby C.W.B. Since Professor W. A.{Mr Adams} Whatmough appears to have made out a good case for his theory that though many circumstances may contribute yet the real cause of detonation in internal combustion engines is the comparative high temperature of the exhaust valve, it seems to me that it might be worth while to experiment with an engine having its exhaust and inlet valves pocketed either side or overhead, and fit a third valve to close off the aperture between this pocket and the combustion space proper. This would, in my opinion, have many advantages inasmuch as though No. 3 valve would be subjected to the high temperatures of the exhaust gases, yet it would be cooled down again by the incoming charge. The period of opening of the 3rd valve would, of course, be roughly double that of either of the other valves, that is to say, it would open as the exhaust valve opened and close as the inlet valve closed, though it might be found that a little lag or lead or both would be advantageous in practice. The other advantages which I think would accrue are as follows:- Higher compressions could be used without fear of detonation, fuels having lower self ignition temperatures could be utilised, - larger valve areas would be possible, - some of the heat now wasted would be utilised to improve carburation of incoming wet mixtures, - With the two original valves opposed in a pocket the incoming charge would impinge upon both the exhaust valve proper and No.3 valve, and though there might be some disadvantage in the shape of increased wire drawing, yet I think this would be off-set by the advantages of increased turbulence,- by utilising the hot valves to improve carburation and utilising the incoming cooling gases to lower valve temperatures, some economy in fuel might result, also the volumetric efficiency of the engine might be increased by a reduction in temperature of hot spot. I suggest, with all due deference, that with this type of valve gear perhaps combined with a modified Ricardo head, | ||