The Trials of the Mercedes-Benz Diesel-engined Lorry.
Page 21
If you've noticed an error in this article please click here to report it so we can fix it.
TlIE reports of the technical cominittee of the Royal Automobile Club on two trials carried out with the Mercedes-Benz lorry from September 10th to 15th have now been published. The object of the trial on the first day was to obtain records of fuel consumption, water consumption and facility of starting the engine. The distance run was 514 miles and the average speed, excluding, stops, was shown to be 7.9 m.p.h. The consumption of fuel was at the rate of one gallon per 6.58 miles, and as the total pay load was 12 tons 51 cwt. and the total load of the vehicle and trailer 19 tons 151 cwt., this gave the equivalent of 80.8 net ton-miles per gallon and 130.2 gross ton-miles per gallon. The water consumed amounted to 3 pints. During the trial the engine was started on 19 occasions—once when cold and 18 times when warm. When first starting from cold, current was passed to the heating element for 30 sees., the engine being started by the starter 10 secs. later. On the second occasion the heating element was used for 22 secs., the engine starting 9 sees. later, but none of the other 17 starts took longer than 2 secs.
The object of the trial on the other five days was to obtain records of general reliability, consumption of fuel, oil and water and facility of starting engine. The total distance covered was 6911 miles and the average speed, excluding stops, was 17.7 m.p.h. In this case no trailer was hauled, so that the pay load was 6 tons 51 cwt. and the total laden weight 11 tons 121 cwt. Fuel was consumed at the rate of one gallon per 13.48 miles, equivalent to 84.7 net ton-miles per gallon and 156.5 gross ton-miles per gallon. Oil consumption was at the rate of one gallon per 7001 miles and 131 pints of water were consumed during the trial. The engine was started when cold on 10 occasions, after current had been passed to the heating element, the longest time taken to start being 48 secs. and the shortest 19 secs. There were 48 other starts, none of which took longer than 4 sets.
The valve tappets of two of the cylinders were adjusted twice, and on one occasion a fuel-injeetor valve of one of the cylinders bad to be changed. When running at a steady speed no smoke from the exhaust was observed, but there was a slight emission of odorous smoke when abrupt changes of engine speed or of throttle opening occurred, as when changing gear.
The fuel used was found to be gasoil having a specific gravity of .865 and a closed flash-point of 185 degrees F.