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High Load HCCI Operation Using Different Valving Strategies in a Naturally-Aspirated Gasoline HCCI Engine

2012-02-16
This session focuses on kinetically controlled combustion. Experimental and simulation studies pertaining to various means of controlling combustion are welcome. Examples are research studies dealing with temperature and composition distribution inside the cylinder and their impact on heat release process. Studies clarifying the role of fuel physical and chemical properties in autoignition are also welcome. Presenter Hanho Yun, General Motors Company
Technical Paper

The Influence of Fuel Characteristics on Engine Acceleration

1928-01-01
280043
SELECTION of a method and development of apparatus enabling precise and detailed measurement of engine acceleration is discussed in the first portion of this paper, the latter portion of which is concerned with the experimental results thereby obtained. Previous work on the influence of engine conditions on acceleration is generally substantiated. A method is described for approximately deriving the effective air-fuel ratio delivered to the cylinders during acceleration, practical applications are suggested, and limitations are discussed. The effect of fuel volatility on engine acceleration was studied, using six fuels: Aviation gasoline; commercial gasoline; a blend composed of equal parts of the two; and three especially prepared fuels, all of which have equal 20 and 90-per cent points but differ widely at the 50-per cent point. It is shown that the relative values of these fuels for acceleration depend upon the amount of vaporization in the manifold.
Technical Paper

Automobile Practice in Europe

1928-01-01
280037
EUROPEAN trends in some of the major features of engine, chassis and body design and in several items of equipment are reviewed in this paper; which is based on the observation and analysis of the British engineer editor who is its author, and of the staff of The Motor, of London, during the last five years. Although American automotive engineers who follow European practice are acquainted with most of the designs here shown and described briefly, this paper is of interest and value as showing the present principal lines along which development is taking place abroad. Popular chassis types are divided into three classes: (a) the “baby” four-cylinder car of 7 to 9 hp., Royal Automobile Club rating; (b) the “family-type” four-cylinder car of 12 to 14-hp. rating; and (c) the light six-cylinder car of 15 to 20-hp. rating. Typical acceleration curves for well-known cars in each of these classes are given, as well as cylinder dimensions, volumetric capacity, car weight and price.
Technical Paper

Progress in Honing-Machines and the Honing Process

1928-01-01
280060
CYLINDER finishing by rough and finish-boring with wide tools, which was thought good enough during the first dozen years of the automobile-production period, was supplanted by reaming and grinding. Later, cast-iron and copper laps were used, but all these methods were slow and did not produce the fine finish for which a demand developed. Experiments were begun about 1920 with the process known as honing. Five years later the company with which the author is connected converted one of its drilling-machines into a single-spindle honing-machine. Other companies made similar conversions. The first honing-head was introduced in 1923. Not until three years ago, however, did honing begin to be regarded as a real production-method possibility. Since then, very rapid progress has been made and numerous improved machines, honing-heads and honing-stones have been produced.
Technical Paper

The Packard X 24-Cylinder 1500-Hp. Water-Cooled Aircraft Engine

1928-01-01
280064
AFTER outlining the history of development of the Packard X engine, the author states the legitimate position in aviation deserved by the water-cooled aviation-engine of this type and predicts large increases in the size, speed and carrying capacity of airplanes within the near future. Passing then to a discussion of the important features of the X-type engine, various illustrations of its parts are commented upon. The cylinders are built-up from steel forgings, with all welds arranged so as to be subjected to no excessive alternating stresses. The novel features of this cylinder design lie in the fact that the valve seats are entirely surrounded by water and that water space is provided above the combustion-chamber and below the top plate of the cylinder. The cylinder-head is extremely rigid, resisting deflection and assuring the maximum integrity of valve seats. The valve ports are machined integrally with the cylinder-head and are not welded thereto as in the Liberty engine.
Technical Paper

Diesel Engines for Aircraft

1929-01-01
290057
ALTHOUGH the author and his associates have designed, built and tested a Diesel airplane-engine, a description of the mechanical details is omitted because the engine is still in the experimental stage. The general subject of Diesel engines for aircraft is therefore presented in its broader aspects. Typical indicator-diagrams of a gasoline engine and of a Deisel engine are compared as a means of ascertaining whether the pessimistic attitude that the Diesel engine cannot be made light enough for aircraft-propulsion purposes is justified. These considerations lead to the statement that, since a practicable Diesel aircraft-engine must run at speeds five or six times as fast as the stationary or marine-type of Diesel powerplants, whereas the ignition time-lag is substantially the same, it can be seen that the high-speed engine demands a different type of combustion than does the low-speed Diesel.
Technical Paper

Effect of a Centrifugal Supercharger on Fuel Vaporization

1929-01-01
290077
SUPPLEMENTING the results of an investigation at the Massachusetts Institute of Technology on supercharging a single-cylinder automobile engine which were presented at the 1928 Annual Meeting, this paper reports a study that was made to determine whether the mechanical action of a high-speed centrifugal supercharger improves engine performance by increasing the degree of atomization and vaporization of the fuel in the inlet manifold. While changes in the degree of fuel atomization and vaporization might be measured directly by sampling the gases as they pass to each cylinder, an indirect evaluation of these changes by measuring their effect on engine performance was considered more practicable. Tests were made on a six-cylinder automobile engine connected to an electric cradle-dynamometer.
Technical Paper

Mixture Distribution

1930-01-01
300007
HOPING that discussion and dissemination of information on the fundamentals of distribution routine will continue, the author reiterates known facts, which include (a) the method of charting distribution progress, (b) a suggestion for locating the error in distribution and (c) a series of thoughts on construction. The paper is divided into two parts, the first being a study of distribution routine and the other a discussion of a few of the problems that are met every day in the search for perfect distribution. Complete satisfactory distribution and the quantitative measurement of its quality are the two major problems of distribution. The interrelation of these problems is mentioned and the complexity of the subject of distribution is emphasized by listing nine detailed factors, the point being made that if the information that engineers have on these items could be collected and codified considerable progress would be made.
Technical Paper

Cold Carburetion

1930-01-01
300006
EXPERIMENTS made and methods employed to obtain satisfactory engine operation without the addition of heat to the fuel-air mixture are described, as it is known that the power output of an engine is greater as the temperature of the mixture is lower and that higher compression can be used with lower mixture-temperature. The work was initiated with a single-cylinder engine in which kerosene was used as a fuel to ascertain the results that could be obtained without vaporizing the fuel in the manifold, the liquid being added to the air in the valve-chamber as the air entered the combustion-chamber. As satisfactory results followed, the next step was to devise and apply a mechanism based on the same principle to a multi-cylinder engine. The first and succeeding carbureter-manifold combinations used are illustrated and described.
Technical Paper

Aluminum Cylinder Heads Urged as Way to Better Design

1933-01-01
330007
MEASURED gains in performance obtained by using aluminum instead of iron for cylinder head material come from the increased compression ratios possible, Mr. Kishline says, and recommends higher ratios “as a logical means for the engineer to use in creating better transportation.” He gives actual figures taken from observed dynamometer performance showing comparable results on similar engines with aluminum and iron cylinder heads. Desirable features of aluminum heads are presented, after which are discussed design improvements necessary if such heads are to be used successfully. Differences in combustion phenomena resulting from use of iron and aluminum heads also are outlined.
Technical Paper

Commercial Application of Diesel Engines in Heavy-Duty Motorcoaches and Trucks

1932-01-01
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.
Technical Paper

Bending Moments in the Master Rod of a Radial Aircraft Engine

1932-01-01
320069
HEREIN are presented the results of an investigation of the bending moments in the master rod of a radial aircraft engine by a graphical method, and a simple formula derived therefrom for approximating this moment in similar engines. The bending stress in the master rod comes from turning moments about the crankpin axis caused by the action of the articulated rods due to gas-pressure and inertia forces and also by the inertia forces in the master rod itself. Charts are presented that show the magnitude and fluctuation of these turning moments. Accurate computation of these moments involves much tedious work. A method of approximating them with sufficient accuracy for engineering purposes is given for the case of a nine-cylinder radial aircraft engine. The method is applicable also to non-radial engines and to radial engines having other than nine cylinders, but in these cases investigation of the turning moments due to the gas loads in certain cylinders seems advisable.
Technical Paper

How the Design Engineer Views Manufacturing

1932-01-01
320064
AS engineering standards have risen, the need for production ingenuity has become greater than ever before. The engineer looks to the shop for major assistance in realizing his ideals of improved products. He expects the shop voluntarily to reduce the variations from dimensional specifications and to improve its facility to meet changes in design. Refinement in design is useless unless the shop can accurately hold the dimensions. Powerplant characteristics are largely controlled by the accuracy of centers and roundness and straightness of bores in cylinders and bearings. Crankshaft balance, quiet valve tappets and uniformity of weight and fit of reciprocating parts are all dependent upon accuracy of machine operations. To be able to make design changes in the product without great expense is vitally important. Tools must be designed with facility for change. Fixed-center boring machines are to blame for considerable engine trouble and may make design changes prohibitively expensive.
Technical Paper

Scavenging by Large Valve-Overlap Increases Power and Economy

1933-01-01
330044
SINCE the power output of an engine is practically proportional to the weight of the charge, the object has been to increase the weight of the charge burned. The weight of charge inducted by an aircraft engine and the supercharger power required to supply this charge depend among other factors upon how completely the engine is scavenged. In the conventional four-stroke-cycle engine only the exhaust gases in the displacement volume are forced out of the cylinder by the piston on the exhaust stroke; consequently, the engine cannot induct a charge of greater volume than that of the displacement volume, whereas if the clearance volume could be scavenged also, the engine could induct a charge equal to the displacement plus the clearance volume.
Technical Paper

HOW VERSATILE ENGINEERING MEETS PUBLIC DEMAND

1933-01-01
330032
Irritated by statements of some alleged economists to the effect that, except for changes in the appearance of motor-cars, the automobile industry has stood still for the last five years, the author of this paper, who is affectionately regarded as the dean of automobile engineering in this Country, spoke at meetings of the Philadelphia and Metropolitan Sections of the Society on the many car and engine improvements made in recent years. Mr. Crane's remarks, as reported stenographically and embodied in this paper, deal chiefly with engines. He points out that extensive highway improvement and the consequent public demand for higher car speed have forced engineers to design more powerful and more versatile engines without increasing the weight. High-speed engines were of necessity the answer, and these brought the problem of eliminating roughness of operation and preventing transmission of vibration to the chassis.
Technical Paper

Further Investigation of Fuel Injection in an Engine Having Spark Ignition

1932-01-01
320026
THIS INVESTIGATION of fuel injection with spark ignition is a continuation of work previously reported,3 which was carried on in the aeronautic-engine laboratory of the Massachusetts Institute of Technology. Although a four-cycle engine was used, the fuel was injected during the compression stroke so that the results might be applicable to the two-stroke cycle without possibility of loss of fuel through the exhaust. Among the effects studied were those of stratification and of late injection or late ignition as a means of controlling detonation with high compression. Fuels used were aviation gasoline, ordinary Diesel fuel and hydrogenated fuel oil, the last seeming to offer interesting possibilities. Directed turbulence was found to be essential for good distribution of the fuel in the cylinder and satisfactory operation of the engine.
Technical Paper

The Automobile-Type Engine for Marine Service

1931-01-01
310049
THE SUCCESS attained by marine engines as built by the manufacturer of motor-vehicle engines clearly proves that such engines are entirely suitable for marine service provided rugged automobile, truck or motorcoach engines are used as a basis. However, this involves the necessity of applying the principles of marine design and practices. The author describes and illustrates such an engine developed and built by a leading motor-car-engine manufacturing company. This makes possible the use of cylinder blocks, crankshafts, pistons, valves, tappets and many other minor parts used in the motor-vehicle engines. The outstanding advantage is the use of modern methods of production, equipment, quantity purchasing and the financial resources of the automobile industry.
Technical Paper

Piston-Ring Progress

1932-01-01
320002
THREE newly developed instruments-for piston-ring measurement, for ascertaining the radial pressures exerted and for determining “How rough is smooth?”-are described and their uses discussed. The last is a device to determine the smoothness of cylinder finish and predetermine piston-ring life. By all these means, the minute dimensions and characteristics of piston-rings can be studied and evaluated. The authors call attention to the progress made in the last few years in piston-ring design, together with the important factors contributing to successful performance and long life of piston-rings. They state that considerable work has yet to be done before complete specifications for all diameters and types of ring can be given to the industry; however, the progress they describe has been made in ring equipment for high-speed engines under 4 in. in cylinder diameter. They believe that the fundamentals apply to piston-rings for all uses.
Technical Paper

Development of a Heavy-Duty V-12 Engine

1932-01-01
320052
REASONS for designing an engine with 12 cylinders for fire apparatus, motor-trucks and motor-coaches are set forth by the author. Among them were the requirement for 225 hp., a speed range of 200 to 3000 r.p.m. with little torsional vibration and torque-reaction effect, and economy of space. The design adopted has its cylinders in two rows of six each, disposed at an included angle of 30 deg. The statement is made that it can be installed in the space occupied by a 150-hp. six-cylinder engine. Advantages claimed for setting the cylinders at this angle are that the engine can be made narrow, so that all cylinders and the crankcase can be cast in one block; that the accessories can conveniently be placed outside; and that the synchronism of impulses that causes torsional vibration can be avoided. Vertical valves are operated from a central over-head camshaft by rocker arms that carry rollers at one end and are split horizontally at the other end.
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