Commercial Application of Diesel Engines in Heavy-Duty Motorcoaches and Trucks 320070
COMPARATIVE tests were made, both on the block and in the same motorcoach chassis, of a 525-cu.-in. gasoline and a 495-cu.-in. Diesel engine. The block tests are reported fully in charts, including curves for torque and power against piston displacement and engine weight. Corrected curves are given on the basis of equal piston displacement and for the Diesel engine throttled enough so that it would not smoke. Road tests included fuel consumption, acceleration, hill climbing and top speed, which are also recorded in charts.
Other sections of the paper deal with costs of manufacture and maintenance and present and prospective conditions as to supply and cost of Diesel fuel. Stress is laid on the facts that automotive Diesel engines require a much higher grade of fuel than do the larger and slower Diesel units and that more gasoline than fuel oil can be obtained from a given amount of crude.
Conclusions are that its characteristic lower torque per unit of displacement would make necessary a Diesel engine having a larger number of cylinders than a gasoline engine for the same job, introducing major problems in provision of space in a motorcoach or truck and in design and manufacture. Acceleration obtained from the two engines is thought to be in proportion to their fuel consumption.
Discussers criticize the Diesel engine selected as not representing the best types available. They present examples of economical operation of Diesel-equipped vehicles and evidence that Diesel fuel should never be as costly as the more highly refined gasoline.