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).
The effects of air temperature on engine performance, including pinking, carburation, fuel consumption, and warming up.
| Identifier | ExFiles\Box 123\1\ scan0101 | |
| Date | 26th August 1936 guessed | |
| -3- Effect on Pinking As the air temperature was raised so pinking became more intense. Alteration to the ignition advance cut out pinking but reduced power. There is no doubt in the writer's mind that severe pinking troubles experienced on heavy duty vehicles during very hot weather are caused by excessive bonnet temperature. Effect on Carburation The test engine was run with cold water circulating in order to reduce the warming effect of the water on the induction system. With the air temperature set at 80°F.{Mr Friese} perfect pulling at 500 r.p.m. under full load was obtained without signs of piling up; power output was slightly lower than at normal working temperatures owing to lower mechanical efficiency due to the coolness of the cylinder walls. Petrol Consumption At first sight it would be thought that a high temperature intake air would reduce fuel consumption. The writer made many tests but failed to find any benefit. The leanest settings possible were used but increasing air temperature only reduced power output without effecting economy. Rapid Warming Up Here lies the great advantage of the device. When first the instrument was tested the time taken from starting to raise the air temperature from 70°F.{Mr Friese} to 90°F.{Mr Friese} was 3 minutes 25 seconds. Larger pipes to the heater coil were then fitted and the time was reduced to 1 minute 30 seconds. By suitable design 90°F.{Mr Friese} could be obtained in 60 seconds on a really cold morning. Efficiency of the Air Heater As predicted from the air flow tests the air heater gave a slight increase in power working at the same temperature as the carburetter i.e. heat disconnected. [Footer Text] R.P.81 S. SMITH & SONS (Motor Accessories) LTD. CRICKLEWOOD WORKS, LONDON, N.W.2. CONTINUATION NO. | ||