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The turbocharged engine, by operating at intake and discharge conditions several times higher than atmospheric pressure, is capable of increasing its specific output to several times that of its naturally aspirated version, and at better fuel economy. Successful integration of the turbocharger requires recognition of the interrelation and interaction of both reciprocating and turbo machines and changes in their performance characteristics. This paper discusses the relation of intake manifold pressure to engine load and speed as a function of turbocharger performance, and methods of improving performance of the engine at part speed without excessive overboosting at rated speed.

There are many types of intake air cleaners available for gasoline and diesel engines under 30 horsepower. Oil impingement, oil bath, and dry type air cleaners have major differences in performance. The selection of an air cleaner for a small engine involves an evaluation of cost vs. performance, based on the degree of engine protection required in the final application of the engine

Three industrial engines, including one engine at three compression ratios, were operated on LP-gas mixtures and on gasoline. The work was performed by Ethyl Corp. Research Laboratories under contract with the Natural Gas Processors Association and the National LP-Gas Association. The paper presents directly comparable information on engine performance and fuel economy when operated on gasoline and LP-gas. Information is presented to indicate the LP-gas antiknock quality needed to satisfy the engines at best-power fuel-air ratio and various ignition timings.

The question of whether increasing the fuel economy of light-duty natural gas fueled vehicles can improve their economic competitiveness in the U.S. market, and help the US Department of Energy meet stated goals for such vehicles is explored. Key trade-offs concerning costs, exhaust emissions and other issues are presented for a number of possible advanced engine designs. Projections of fuel economy improvements for a wide range of lean-burn engine technologies have been developed. It appears that compression ignition technologies can give the best potential fuel economy, but are less competitive for light-duty vehicles due to high engine cost. Lean-burn spark ignition technologies are more applicable to light-duty vehicles due to lower overall cost. Meeting Ultra-Low Emission Vehicle standards with efficient lean-burn natural gas engines is a key challenge.

WHILE recognizing that American interest in the 10-hp. type of car is academic at present, Mr. Pomeroy shows reasons why its design warrants close study. He describes an English passenger car that has adequate body capacity and an engine less than half the size of the smallest American engine, one only about one-third the size of the typical six-cylinder engine as fitted to American cars of the $500 to $600 class. Specific data relating to the English 10-hp. type of car are presented, together with running comment thereon. The statement is made that the case for the 10-hp. type of car rests upon the undoubted and even enthusiastic satisfaction it is giving to a very large number of highly experienced and sophisticated motorists with just as high ideals of what an automobile should be as those in any other country.

THIS authors sees a need, in the near future, for commercial vehicles with engines of 1000 to 1200 hp - powerplants that yield high outputs but require limited space. He sees an immediate need for more and more horsepower per cubic inch of piston displacement and per unit of space for the engine. He directs attention to six design potentials which may supply the answer: (1) the gas turbine; (2) supercharging; (3) aircooled diesels; (4) higher engine speeds; (5) 2-stroke diesel improvement; (6) compound engines. He also links the future development of the internal-combustion engine with basic improvement of components through simplification, calling for the elimination of extraneous gadgetry.

To recommend supplementary design criteria to enhance the endurance, reliability, and dependability of transport aircraft wheels and brakes.

To recommend supplementary design criteria to enhance the endurance, reliability, and dependability of transport aircraft wheels and brakes.

Virtually all production engines today have some level of electronic control. As features have been added over the years, some of these Electronic Control Units (ECU's) have grown significantly in complexity, size and cost. As Variable Valve Actuation (VVA) systems evolve from simple, mechanically operated systems such as cam phasers to full VVA systems, electronic systems will also need to evolve to control them. This evolutionary path forces many system-level questions to be considered. Some global questions that will need to be considered as the industry continue on this path, are: “What is the optimal level of electronics integration?” “At what point should a distributed engine control system be considered?” There are several key points that need to be considered to properly make these decisions, many of which will be addressed in this paper. A process for how these decisions might be made for a given system will be discussed.

With the passage of the federal Clean Air Act, the automotive industry has a clear assignment to reduce automobile emissions drastically by 1975. The control devices presently available have already reduced hydrocarbons 83%, carbon monoxide 70%, and nitrogen oxides 33%. By 1975, these figures must be 98%, 97%, and 90%, respectively. This paper discusses the devices that have been developed to accomplish the reductions to date, and concludes that in the future the crankcase controls will require little change, that the evaporative controls will require some additional improvement but will not change substantially, and that engine modifications do not have much chance of meeting the 1975 standards without a great deal of supplementation. The author feels two methods are available which may be able to reach the 1975 standards: use of manifold reactors and use of catalysts. However, both present problems of materials and thermodynamics, due to high exhaust temperatures.

Since the sizes of the flywheel and clutch have been enlarged due to downsizing of diesel engines, the mass and moment of inertia at the crankshaft rear end have increased. Consequently, the serious bending stresses have appeared in the crankshaft rear. This paper describes the characteristics of those serious bending stresses, based on the mechanism for whirl resonance. The whirl resonance is largely impacted by the mass of the flywheel and clutch and by the distance from the crank-journal center of the rear end to the center of gravity of the flywheel and clutch.

As the issue of global warming has become more serious, needs for downsizing or weight saving of an engine has been getting stronger, and forces exerted on engine parts, especially force on a crankshaft, have been getting larger and larger. In addition, since a crankshaft is a heavy engine part, needs for saving weight have been getting stronger and stronger. Therefore, determining the mechanism of high stress generation in a crankshaft system is urgently needed. This paper describes the characteristics and mechanism of a severe bending stress caused by the whirl of crankshaft rear end of an inline 6-cylinder medium-duty diesel engine. The authors measured bending stress on the fillets of the crankshaft, and found severe levels of sharp peaks in the stress curves for the crankshaft rear. To figure out why the severe levels of sharp peaks appear, they analyzed and studied the measured data.

A John Deere Model 3010 Engine, a 4-cyl, three-main-bearing, four-stroke Otto-cycle in-line engine, was used in tests measuring crankshaft strains and the deviation of flywheel motion from plane rotation about the axial centerline of the main bearing bores. The crankshaft was run with a 50 lbf and a 127 lbf flywheel at 0.006 in. and 0.008 in. diametral main-bearing clearance over a range of 2000 rpm to 3000 rpm engine speed under no-load conditions. The flywheel exhibited a first-order, forward whirl for all test conditions. Crankshaft stresses were not significantly affected by either the flywheel mass or the main-bearing clearances.

Find out why you should attend the 2025 Noise and Vibration Conference and Exhibition.

This paper reports comparative results for liquid phase versus gaseous phase port injection in a single cylinder engine. It follows previous research in a multi-cylinder engine where liquid phase was found to have advantages over gas phase at most operating conditions. Significant variations in cylinder to cylinder mixture distribution were found for both phases and leading to uncertainty in the findings. The uncertainty was avoided in this paper as in the engine used, a high speed Waukesha ASTM CFR, identical manifold conditions could be assured and MBT spark found for each fuel supply system over a wide range of mixtures. These were extended to lean burn conditions where gaseous fuelling in the multi-cylinder engine had been reported to be at least an equal performer to liquid phase. The experimental data confirm the power and efficiency advantages of liquid phase injection over gas phase injection and carburetion in multi-cylinder engine tests.

HIGH output per cubic inch of piston displacement is desirable not alone for the purpose of being able to transport more payload faster, but more particularly for the invariably associated byproduct of lower specific fuel consumption, and especially at road-load requirements. The only way of accomplishing this purpose is through the use of higher compression ratios, and the limiting factors for this objective are fuel distribution and the operating temperatures of the component parts. A manifold is proposed which not only definitely improves distribution at both full and road loads, but has the inherent additional advantage of reducing the formation of condensate, thus still further facilitating a reduction in road-load specific fuel consumption. Hydraulic valve lifters, obviation of mechanical and thermal distortion, and controlled water flow are the essentials in improved cooling.

Cast iron is generally thought of as a weak, dirty, cheap, brittle material that does not have a place in applications requiring high strength and defined engineering properties. While gray cast iron is relatively brittle by comparison with steel, ductile iron is not. In fact, ductile iron has strengths and toughness very similar to steel and the machinability advantages make an attractive opportunity for significant cost reductions. Gray and ductile iron bar stock is commercially available and can be used as a direct replacement in applications that are currently being made from carbon steel bar. Ductile iron bar stock conversions are very prevalent in many fluid power applications including glands and rod guides, cylinders, hydrostatic transmission barrels and in high-pressure manifolds. Automotive gears are being converted to ductile iron for its damping capacity and cost reductions.

In order to meet the strict exhaust emission legislation and customer's requirements of high power, heavy-duty diesel engines have to have a higher peak firing pressure and higher thermal load recently. It causes serious influence on the reliability and durability of the engines and engine parts, pistons in particular. The pistons for the next generation heavy-duty diesel engines are required to withstand more than 20 MPa of the peak firing pressure and higher thermal load, productivity of course. Nodular cast iron (NCI) pistons are one of the answers that could satisfy the requirements mentioned above. It is well known that NCI pistons have a lot of advantages but not popular. The difficulty of the casting technology and the quality control are the major reasons. Hino P11C engine has adopted it and kept it under mass production since 1991 and approx.20000 units of total production volume without any troubles.

A new air-fuel ratio control algorithm and its effect on automotive engine operation is described. The system consists of a wide range air-fuel ratio sensor and a single point injector with an ultrasonic fuel atomizer. The air-fuel ratio control adopts PID control and it has built-in learning control. A 16 bit microcomputer is used for the latter. The results of three studies are given. The first deals with adaptive PID gain control for various conditions. The second is the new learning control which uses an integration terra. The third is individual cylinder air-fuel ratio control.