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The paper gives the value of certain factors in engine design that are good practice and uses these values to calculate the horsepower of a four-cylinder engine. The author holds that the deciding factor in comparing four-cylinder engines with those of the same displacement but with a greater number of cylinders, is the thermal efficiency. Both the cooling medium and the mechanical losses increase in proportion to the number of cylinders. He suggests in closing, that the demand for power output beyond the possibilities of four cylinders must be met by the use of a greater number.

The author confines his discussion to engines used on pleasure cars, inasmuch as practically all commercial vehicles use the four-cylinder type. The performance expected of their cars by automobile owners is outlined, particularly as regards performance, durability and maintenance cost. In-asmuch as the horsepower required is often determined by the acceleration demanded, the argument in favor of four-cylinder engines is based mainly on a comparison of its acceleration performance with those of engines having a larger number of cylinders. A number of acceleration curves are given for these engines. The paper next considers smoothness of operation at low, medium and high running speeds, asserting that the decrease in inertia forces due to lighter reciprocating parts has made it possible to increase the speed and thus reduce remarkably the vibration of the four-cylinder engine.

The author gives a brief review of developments during the past year in the construction of aeroplanes, particularly as affected by the European War. He takes as an example the Renault twelve-cylinder engine, citing the respects in which the present differs from previous models. Such factors as the changes in cooling systems, method of drive, valve construction and starting devices are considered. The requirements of aeroplane engines, such as constant service, high speeds (of aeroplanes) and stream-line form of engines and radiators, are outlined. Propeller requirements are dealt with at length, curves being given by which the efficiency and diameter of the propeller can be obtained. In conclusion a number of different engine installations are illustrated and compared.

This paper is mainly an argument in favor of the use of large, single rear wheel truck tires instead of smaller dual tires. Although the practice of using large singles is comparatively new, the author gives the results of experience and research to show the advantages of the newer method of rear tire equipment. In developing his arguments in favor of single tires, the author goes into the history of dual tire application to show why it was necessary to use two tires in the earlier days of truck operation. As the necessity for increased carrying-capacity grew, tire manufacturers found the then existing single tire equipment inadequate, and they set about to develop suitable equipment to meet the new condition, the result being dual practice. The method of attaching the earlier dual tires is shown to have been poor, resulting in circumferential creeping of the whole tire to a much greater extent as the width of the dual equipment increased.

The authors first define the elementary conditions governing combustion efficiency, dividing these conditions into three main classes. They next compare engines operating on constant volume, constant temperature and constant pressure cycles, dealing specifically with the Otto, Diesel and semi-Diesel types. The main part of the paper is devoted to an outline of the constant pressure cycle, analyzing its advantages as compared with the merits of the constant volume cycle now used in internal-combustion engines. The paper is concluded with a detail description of a proposed constant pressure engine.

The author points out the diversity of opinion on what constitutes desirable car performance in the minds of engineers and of the public generally. He believes this is largely due to the great diversity of claims which have been made in advertising literature and decries the sort of tests which have been made the basis of this publicity, pointing out that a majority of them are conducted under such conditions as make it practically impossible for the car owner ever to duplicate or confirm them. The kind of an expression or test which will inform the buying public most is one which will tell what the car will do in the hands of the average owner, and define the conditions under which a demonstration of this ability can be made, such conditions to be relatively simple and easy of fulfillment.

There is opportunity for the exercise of considerable ingenuity and mechanical skill in developing automobile signaling apparatus, but the basis of any system or appliance of this nature that is destined to meet with lasting success is quite as much a matter of psychology as mechanics. No signaling apparatus can wholly succeed of its purpose unless two phases of the human equation have been properly considered. In order to serve its purpose as a warning, the signal must penetrate the wall of partial insensibility with which every human being unconsciously surrounds himself by directing his thoughts, along some particular line. Were the pedestrian fully aware of the dangers that beset him in the street, he would require no reminder of his peril. But his thoughts are elsewhere, and, for the moment, he is unconscious with respect to his surroundings.

Many areas of the world are in various stages of development which frequently includes a rapid increase in the motor vehicle population. As a result, some areas are beginning to show the effect of increased motor vehicle use on air pollution. The vehicle's contribution to California's air pollution has long been recognized and studied, and measures have been implemented to reduce emissions from motor vehicles. The history of light duty vehicle emission control in the South Coast Air Basin of California is reviewed. Emission reductions achieved, current levels, projected future emissions and the need for further emissions reductions from light duty vehicles are discussed. For other areas of the world where motor vehicles contribute to air pollution, suggestions are made which can improve the effectiveness of emission control efforts; which should be consistent with political and economic realities, and efforts to achieve international harmonization of standards.

In order to achieve lean burn engine control system, it is necessary to develop high accuracy air fuel ratio control technology including transient driving condition and lean burn limit expansion technology. This paper describes the following. 1 The characteristics of the transient response of the fuel supply are clarified when various kinds of air flow measuring methods and fuel injection methods are used. 2 To achieve stable combustion in lean mixture, fine fuel droplet mixture, whose diameter is less than 40 μm, needs to be supplied.

Unsteady laminar flame propagation confined in a closed cylindrical combustion bomb is studied by numerical computation for an axisymmetric two-dimensional laminar flame. Computation includes complete two-dimensional unsteady Navier-Stokes equations of change for a chemically reacting propane-air mixture. Implicit Continuous fluid Eulerian, Arbitrary Lagrangian Eulerian finite difference technique, simplified reaction kinetics models, and artificial flame stretching transformation and inverse transformation were adopted in the calculation. Physically realistic flame behavior can be demonstrated even with rather coarse computing cell size, simplified reaction kinetics models, and personal computer level low power computing machines.

A procedure has been developed for evaluating equivalent drive cycle emission results from raw exhaust gas emissions data obtained from an engine under test on a computer controlled Vehicle Simulator Engine Dynamometer. The emitted species data is integrated with the air intake flow rate to determine the total mass of emissions, after correcting for the reduction in exhaust gas mass due to precipitation of the moisture of combustion. This procedure eliminates the need for the Constant Volume Sample (CVS) System attached to the vehicle exhaust while undergoing simulated drive testing on a chassis dynamometer to evaluate compliance of the test vehicle with the Australian Design Rules, ADR27 and ADR37. Sources of error with the procedure are examined by comparing the fuel consumption measured using a volumetric technique during the test with that evaluated by a carbon balance procedure as given in the Australian Design Rules.

The sequential fuel injection, in which fuel is injected into swirl being generated for mixture stratification, was used to pursue the potential of a lean burn engine for its performance improvement. As a result, it has been found that the most effective method to increase thermal efficiency while reducing NOx emission level is to combine a high-compression compact combustion chamber located on exhaust valve side in cylinder head with DICS (Dual induction Control System). This method was used to build a high-compression lean burn concept vehicle, which was evaluated for compliance to various emission standards. Testing showed that the concept vehicle can improve fuel economy by 10.5% on the Japanese 10-mode cycle, by 8.3% on the ECE mode cycle, and by 6.3% on the U.S. EPA test mode cycle while meeting respective emission standards.

In this paper a computer simulation study on the effects of steering parameters on lateral dynamics of the guideway bus to contribute to a development practice of designing optimum steering control system are dealt with. A stability limit of vehicle lateral motion is analyzed and an emphasis is laid on the effects of moment of inertia of a conventional steering wheel and lateral elasticity of the guide rail which have proven to reduce the critical vehicle speed. It is pointed out conclusively that a normal bus equipped with additional simple guidance equipments can be guided smoothly on a simple guideway at adequately high vehicle speed.

The influence of the tyre properties on the driving behaviour of single-track vehicles has been measured by performing running tests with full-scale vehicles. The indoor dynamic tyre measurements using the sideslip angle as the input signal reveale that the sideforce and self-aligning moment characteristics are helpful explaining the measured driving behaviour. The obtained tyre parameters values and second order equations have been implemented in the simulation program ADINA-MOBSIP. This program is specially conceived for the simulation of the driving behaviour of single-track vehicles and is based on the finite element method.