A Test Report on The Lanova Combustion System
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Brief Details of Certain Results Obtained by the Technical University of Munich in Experiments with an Oil Engine Embodying this Well-known Continental Principle
I-Ici our issue dated January 6, we published a description of the Lanova combustion system, which is being developed by a holding company on the Continent and which is employed in the Henschel oil engines for road-transport vehicles produced by Henschel and Sohn A.G., Kassel. We are now able to publish some details of results obtained from tests conducted at the Laboratory for Internal-combustion Engines at the Technical University of Munich, under the supervision of Prof. Dr.-ing
A. Loschge. • A Lane va-type four-cylindered fourstroke oil engine of 3.049-in, bore and 4.570-in, stroke was tested in October, December and, finally, on January 12 and 13, under a variety of working conditions, and the summary of results includes the following remarks:— The mean effective pressure could be brought to 111.5 lb. per sq. in. without an unsatisfactory exhaust, thus indicating the relative efficiency of combustion. The air excess at maximum load was 1.13, 89 per cent. of the volume of air being used in combustion, from which it is deduced that a high degree of mixture of fuel and air results from the turbulence system employed.
Satisfactory Fuel-consumption Figures.
The volumetric efficiency was shown to be 84 per cent at 1,000 r.p.m. Fuel consumption per b.h.p.-hour at 1,000 r.p.m. under all conditions of load between 27 b.h.p. and 70 b.h.p. proved to be less than 0.447 lb., the minimum reading being 0.410 lb. at a load of 45 b.h.p. With the crankshaft speed increased to 1,400 r.p.m., the minimum fuel consumption increased only to 0.415 lb. per b.h.p.-hour, the maximum power output at that speed being 94.2 b.h.p. The maximum mean effective pressure at all rotation speeds between 600 r.p.m. and 1,000 r.p.m. was 111 lb. per sq. in., iecreasing the speed to 1,200 r.p.m. the reading dropped only to 109.5 lb., and even at 1,400 r.p.m. it was shown to be 106.7 lb. The final compression pressure was 341 lb. per sq. in., the maximum pressure shown on the diagram being measured at between 597 lb. and 625 lb. per sq. in. The practical result of these figures was stated to be very smooth and quiet running over the range of crankshaft speeds.
Brief details of the starting capabilities of the engine in cold weather are given in the report. In an outdoor temperature of 23 degrees F. and with the laboratory doors wide open, ignition was obtained with a cold engine after eight crankshaft revolutions and, immediately after starting the engine proved able to hold a minimum speed of 160 r.p.m. No heater cods were used for the above test, but only an orthodox electric starter. Readers may be reminded in this connection that the air chamber used in this system can be regulated by means of a hand-operated valve, giving the effect of a higher compression ratio which naturally gives the extra heat tequired to obtain the initial ignition from an absolutely cold engine.
A. feature of the principle which is emphasized by the Lanova engineers is that not merely is the air and fuel mixture, by reason of the peculiar form of the combustion chamber, set into a whirling motion, but this motion is mechanically controlled during the combustion process.
In the early stage of injection the fuel is prevented from finding a large quantity of air, and this, resulting from the shape of the combustion chamber, is claimed to give a smooth commencement to the power stroke. The main combustion is arranged to take place in the valve chamber, which is well cooled. The pressure in the air chamber is exceedingly high, whilst the pressure in the combustion chamber itself does not reach a particularly high value, and the designer's aim in this respect has been to relieve the crankshaft bearings of excessive loads.
Cramped Valve Layout Avoided.
Another point that is emphasized is that the nozzles and air chambers are easily accessible and, as the nozzle is not located between the valves, an easier layout of the ports becomes possible, giving a high degree of cooling to the combustion chamber.
The accompanying graph of one of the six-cylindered engines not only shows the torque and the brake-horsepower readings over the range of the engine speeds, but also indicates the mean effective pressure in relation to the load in brake-horse-power. The almost level contour of the torque curve is particularly noticeable.
The Lanova combustion system is one of the latest of the air-cell systems produced with the object of promoting controlled turbulence, difficult to obtain by the various other methods.