GUARANTEES. TEST RESULTS. OPERATING RESULTS. GAS ENGINE, DIESEL AND STEAM TURBINE EFFICIENCIES. DIESEL INDICATOR CARDS. INDICATOR RIGGINGS. METHOD OF CONDUCTING DIESEL TESTS manufacturers of Diesel engines have been very conservative in the guarantees of fuel consumption of their engines. Table VI gives the standard guarantees of various builders, although all are lowered in tests. All of these guaran tees, with the exception of the McIntosh & Seymour and the Busch-Sulzer engines, exceed the usual European Diesel guaran tees by a marked amount. However, the actual fuel consump tion, by test, of American Diesels is not much greater than those of the European engines. The difference is attributable to the superior workmanship of the latter along with the more developed fuel-injection devices.
Snow Diesel Fuel Consumption.—Figure 184 is the result of a test on a 300 h.p. Snow Diesel. It will be noted that the test gives fuel consumptions that are 20 per cent. lower than this company's standard guarantees.
McEwen Diesel Fuel Consumption.—Figure 185 shows a test on a 65 h.p. McEwen Diesel. The fuel consumption at full load is remarkably low. The increase at three-quarters and half-load over the full-load consumption is quite marked. From this it would appear that the engine's rating was not as high as it should be. In other words, the rating should be raised, making the engine a 75 h.p. unit.
Standard Fuel Oil Engine Fuel Consumption.—Figure 186 is the result of a test on a 120 h.p. Standard Fuel Oil two-stroke cycle Diesel. This test is fairly representative of two-stroke cycle Diesel engines of small powers.
Korting Diesel Fuel Consumption.—Figure 187 shows the results of a test on a 300 h.p. Korting four-cylinder horizontal Diesel.
The fuel consumptions and thermal efficiencies are extremely attractive.
A 100 h.p. Korting Diesel employing tar oil as a fuel was tested with the results appearing in Fig. -188. A light distillate was used as an ignition oil, being injected ahead of the main tar-oil charge. This test is not of great interest to the operator since the results are plainly inaccurate. The thermal efficiency at
half load would appear to approach the full-load efficiency.
Diesel Fuel 189 shows the results of a test on a 500 h.p. Busch-Sulzer Type B Diesel. This test was run without any preparation in the way of engine adjust ments and represents actual operating results.
McIntosh & Seymour Diesel Fuel 190 is the result of a test on a 500 h.p. McIntosh & Seymour Diesel. This engine was one of three installed in a Texas electric plant and was direct connected to a 437 kv.-a. G.E. alternator. In running this test, the fuel consumption per kilo watt hour was obtained at the various loads. Using the builder's guarantee of the generator efficiency, the fuel per brake horse power was computed from the fuel per kilowatt hour. The units were delivering their output to a high-tension line, and the results represent operating conditions.
Table VII outlines complete tests on three 500 h.p. McIntosh & Seymour Diesels direct connected to G.E. alternators. These tests were carried out while the engines were in actual service, delivering current into a 100 kv. high-tension line. The efficiencies of the three units were practically uniform and represent values that are about as high as can be expected in units of this size.
Actual Operating Results.—The preceding figures represent test values at certain stated loads. It is im possible to secure a given load factor . at all times. Consequently the fuel consumption of a Diesel in actual operation will not check with test results. In a few instances, such as with the plant containing the three 500 h.p. engines appearing in Table VII, the plant can operate at prac tically full load at all times. The fuel consumption should then check with test results. In the Paris, Texas, plant the test gave a fuel consumption at full load of .603 lb. per kw.-hr. The actual operating consumption in this plant is .672 lb. per kw.-hr. while the load ranges from three-quarters' to full load. This is but 10 per cent. above the test results.