Search Results

ANALYTICAL methods of investigating engine torque are given in this paper, which is an amplification of the method previously presented by the same author, accompanied by a number of sample analyses. This method is said to be easier to apply to a complete analysis than is the graphical method, and to be adaptable to several types of investigation that cannot be made by the graphical method. In the discussion is given an outline of the mathematics required to follow the analysis. Electrical engineering students are said to receive instruction in all the mathematics required beyond that used in the graphical method.

COMPROMISES are necessary in designing a piston, sacrificing the quality of least importance under the given conditions. Aluminum alloy is seen as a most desirable material because of its high conductivity and low rate of absorbing heat from hot gases. Aluminum-alloy pistons are now made for oil engines with bores up to 18 in., as well as for small gasoline engines, those described in this paper having their expansion controlled by steel bands embedded in the aluminum but not bonded thereto. Slots cast in the piston allow for linear expansion of the alloy without a corresponding increase in piston diameter and change in cylinder clearance. Advantages of strut-type pistons are shown by thermal diagrams. Illustrations show large pistons and engines in which they are used. Cores and steel inserts for producing such pistons are shown also.

In this article the author presents analytical methods for determining the unbalanced inertia force and the tangential effort in a line engine. These methods are thought to be of interest for investigation of the effects of various engine design-features on its vibration characteristics. An equation for the resultant reciprocating force is set forth and methods of expressing the inertia and fluid-pressure torque are given. The determination of minimum and maximum resultants and the balance of inertia and fluid-pressure torques are other topics dealt with. The results of a series of analyses are incorporated in tabular form.

ENGINE power is an expression that has a wide range of meaning. In its most fundamental sense, it is the capacity for doing work developed in the engine cylinders and is limited by the breathing capacity of the engine, that is, its rate of air consumption. The author describes a positive rotary-displacement measuring apparatus designed to overcome the objections often raised to the use of the customary type of air-meter in the induction system. The contribution describes a method for attaining greater accuracy or simplicity of operation evolved in the course of an investigation, and the method described is easily applicable by others who may have similar problems requiring solution.

C. W. SPICER, in a paper entitled Torsional Strength of Multiple-Splined Shafts,3 which was presented at the 1927 Semi-Annual Meeting, gave results of a number of tests which supplemented an earlier series of tests, conducted by him, directed toward the same object and previously reported.4 The results of these practical tests of actual splined shafts all indicate that, while the elastic-limit of the multiple-splined shaft is considerably less than that of a plain round shaft of diameter equal to the diameter of the splined shaft measured at the base of the splines, the ultimate-strength of the splined shaft exceeds greatly that of a plain round shaft of diameter equal to the base diameter of the splined shaft.

This Annual Meeting paper is a report of a series of tests conducted during the summer of 1922 by the authors at the Engineering Experiment Station of Purdue University. The work consisted of research into the operation of internal-combustion engines under comparatively high compression on ordinary gasoline without detonation. The compression-ratio of the engine was 6.75 and the compression pressure was 122 lb. per sq. in., gage. The ingoing charge was passed through a hot-spot vaporizer and thence through a cooler between the carbureter and the valves. Jacket-water temperatures between 150 and 170 deg. fahr. were carried at the outlet port of the jacket. The theory held by the authors as to the causes of detonation of the combustible charge is presented briefly. The source of the two phases of detonation encountered in this work is believed to be overheated areas in the combustion-chamber.