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).
Engine fuel distribution, comparing dry gas versus liquid petrol and evaluating the 'Dorris' scheme.
| Identifier | ExFiles\Box 75\2\ scan0264 | |
| Date | 8th August 1921 | |
| Contd. -2- Hs{Lord Ernest Hives - Chair}/LG23. 8. 21. distribution but you want a dry gas. My answer to that is "Agreed, but where are you going to obtain your dry gas from?" You have proved and we have proved that the worst condition for liquid petrol to pour into the cylinders is when starting up cold. Under that condition there is no means available for providing heating so that there is nothing else for it but for the liquid to be slopped into the cylinders. Now, our contention is that as it is impossible to obtain a dry gas under all conditions, the next best thing is to try and slop an equal amount of liquid into each cylinder. We claim that individually, each cylinder can deal with a slight amount of excess liquid petrol but if one or two cylinders get the lot, then it has an accumulative effect, because of them having an over-rich mixture the temperature of the explosion is very much reduced which means that a particular cylinder can deal with even less liquid petrol so that it builds up until it misses fire either due to over-richness or due to sooting of the plugs. We think it is futile for you crying out for dry gas when it is not to be had. Your tests have shown that under normal running conditions when the engine is warm, there is very little liquid passes into the engine. You go to the trouble of explaining that our cars are used in the Winter, mostly in the cities and are only run for short distances. It is no use crying out for dry gas under those conditions, therefore, we claim that equal distribution of liquid petrol to all cylinders is of prime importance. These arguments are put forward not counting the "Dorris" scheme. We agree now that the Dorris scheme of collecting the liquid petrol opens up a fresh avenue. The Dorris scheme levels up the distribution to all cylinders, that is proved definitely by the fact that there is a tremendous difference in the amount collected from individual cylinders. As you point out the Dorris scheme works exceedingly well without any heating at all. We agree with you. It works very well cold because it provides an equal amount of liquid petrol to each cylinder. You do not imagine for one minute that when you are running with the Dorris scheme and one watches the heavy ends of the fuel pour into the bottles, that the mixture which is passing into the cylinders is a dry gas, it is not, the mixture which is going into the cylinder is absolutely wet but because of equal distribution it can be handled by cylinder conditions. We think that the Dorris scheme has the best possibilities of anything we know of. We are not certain that we should not place the Dorris scheme higher in value than the exhaust heated throttle. There is no doubt that the combination of the two is the best because it leaves much less liquid to be dealt with by the Dorris scheme. Further tests with the exhaust heated throttle are encouraging. contd:- | ||