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A five-vehicle, 64 000-km test with 7.45 litre V-8 engines was conducted to determine if synthetic engine oils provided performance sufficiently superior to that of conventional engine oils to permit longer oil change intervals. The results show better performance in two areas of deposit control; inferior performance with respect to wear protection; and essentially equivalent performance in the areas of fuel and oil economies. Based on these data, it was concluded that synthetic engine oils do not provide the necessary performance required to safely recommend their use for extended oil change intervals. In addition, a cost analysis shows that the use of synthetic engine oils, even at a change interval of 32 000 km, will essentially double the customers' cost compared with conventional engine oils at GM's current 12 000-km change interval.

The terms abrasion and erosion mean different things to various people. Moreover, there are many devices for measuring the response of materials to abrasive wear. The results from such machines do not consistently agree with those of the others because variables that differ in kind and amount are involved. Classification areas that help define the variables are an aid to the selection and application of laboratory and service tests. To three categories previously proposed by the author, and widely adopted, four others are now added for completeness and in hopes that misapplication of the terminology will be minimized. These are described and in several cases linked to better known laboratory tests.

A direct as well as an indirect injection system have been studied in regard to noise, exhaust emissions and fuel consumption on a V-10 diesel engine. The dependency of the sound pressure levels on engine speed, engine load and injection timing is described for both combustion systems. The noise reduction achieved by optimisation of injection timing is shown in relation to the respective changes in exhaust and smoke emission output and fuel consumption.

The need for clear definition of accuracy performance and operating criteria for Load Indicating Systems has been voiced by crane operators, crane manufacturers, and legislative agencies. A thorough study of the existing Recommended Practice was undertaken with the specific goal to upgrade J-376 to permit greater understanding of the minimum performance requirements of Load Indicating Systems.

The overall effect of two methods of turbocharging a direct injection four stroke diesel engine in terms of performance, smoke, noise and gaseous emissions is described. It is shown that the effect of turbocharging is to produce a more socially acceptable engine. Matched turbocharging involving reduced compression ratios produces substantial emissions and combustion noise reductions (up to 16dB) at full load but can increase combustion noise levels considerably (8dB) at light load. Before full advantage can be taken, methods of controlling the characteristics of turbochargers to maintain short ignition delays at all conditions are required, together with reductions in engine mechanical noise levels.

The paper classifies all current automotive engines into four distinct groups relative to engine usage and vehicle noise legislation. The noise characteristics of the engines in each group are widely different except that at their maximum rated speeds the overall noise levels approach the same value The sources of noise rank in different importance according to the size and type of engine. Therefore quiet engine design must also vary. The importance of mechanical noise is emphasised and it is considered that this source could be a limiting factor to future low noise engines.

This paper shows how new formulations of oils, resistant to the particularly severe conditions in four stroke motorcycle engines have been evolved. New bench test procedures, developed from the field, racing surveys and road tests, were used for the study of the following variables : oil film and oil consumption (viscosity), piston failure (scuffing and preignition) oil oxidation (thickening), piston cleanliness (dispersancy, detergency) and low temperature starting properties. INTRODUCTION : SEVERITY OF MOTORCYCLE ENGINES LUBRICATION OF MOTORCYCLE ENGINES ROAD TESTS BENCH TEST FACILITIES TEST PROCEDURE STUDY LOW TEMPERATURE STARTING PROPERTIES CONCLUSION

In order to obtain maximum work from an electric forklift truck, it is necessary from the designer's point of view to maximize systems efficiency. This paper discusses vehicle hydraulic systems and parameters affecting design, realizing that the truck is powered by a battery with finite energy storage capacity. Efficiency of hardware that hydraulics control is shown to be as important as hydraulic hardware selection and design per se, and duty cycle must also share equal consideration.

An engine lubricant was developed for diesel and gasoline engines covering all service and climatic conditions in Central Europe. The performance spectrum and reasons for formulating a SAE 20W-40 multigrade with a viscosity of 4800 cP at 0°F are explained. A review of the development and test work conducted includes studies indicating the lubricants behaviour in gear boxes, hydraulic systems and other off -highway arid construction equipment. Typical examples of European mixed fleet together with service results obtained from the field are demonstrated. Data compiled show stay-in-grade characteristics, excellent wear protection and engine cleanliness. In comparison with SAE 20W-20 and SAE 30 monogrades oil consumption is reduced.

The mushrooming use of hydraulic power is resulting in demands for more flexibility and versatility in the power source. The radial piston pump is particularly well suited to meet present day demands as well as the needs of the future. It permits an unusual degree of flexibility in systems design. This paper will show how this pump is being used as a source of power to operate either open or closed center systems using either open or closed loops. It can be operated with controls which modulate pressure or flow or both, automatically, in response to load magnitude, speed, position, or temperature or in response to operator input and using a mechanical, electrical, hydraulic, sound, or light signal.

It is often pretended that the injection nozzles of diesel engines are substantial noise generators. This statement was investigated on a truck diesel engine with the result that the nozzles are not a substantial source of noise on the engine. The task was to find out the principles as well as the composition of the noise components radiated from the nozzles. Further investigations in an anechoic chamber revealed the cause of the nozzle noise and showed also several possibilities for its reduction.

The contribution to the noise of automotive diesel engines from the DPA rotary fuel injection pump has been assessed by comparing its overall noise with that of a number of engines, to which the pump is, or may be fitted. From this data, a ‘worst case’ has been selected for a more detailed assessment. The noise generating mechanisms of the pump are examined. Two improvements are described which are suitable for mass production with existing facilities, and which reduce the overall noise by 3 to 5 dB (A). An outline of a modular mathematical model is presented which will guide future efforts towards further practical cost-effective noise control.

The latest advances made in the development in a theoretical analysis of piston movement are described, covering the introduction of such new features as non-parallel bores, ring/groove friction, conservation of angular momentum at impact, and kinetic energy loss at impact. A single value of friction co-efficient of 0.2″ is derived from experimental data and the new program is shown to give good agreement with measured piston movement traces. The movement program is used to examine several piston design features in respect of their influence on impact severity and indicates the importance of gudgeon pin offset, piston/liner clearance and gudgeon pin height when considering piston noise. Further study on the features of friction and impact conditions are suggested, and the work is seen to have wider implications in the development of a complete set of piston assembly predictive design techniques.

Diesel trucks have four major noise sources engine, cooling fan, exhaust systems and tyres. It is generally found that on current trucks engine radiated noise is the most important source, the latter being mainly produced by piston slap. Particularly for reducing the noise of IDI engines, where combustion noise is comparatively low, control of piston slap is most important. This paper gives some calculated results to predict piston behavior and compares them with measured information on engine noise and cylinder liner vibration where piston slap control measures have been taken. From the experiments carried out at Mitsubishi Motors Corporation it is concluded that offsetting the piston pin is both the easiest and cheapest method of controlling piston slap on current production engines.

The effects of using different combustion systems on engine noise are reviewed including an examination of noise reduction methods such as shielding, enclosure and structural modifications. Comparisons are made of direct injection and indirect injection systems and a new noise prediction formula for IDI engines is proposed. The use of turbocharging is examined and the limiting effects of mechanical noise noted. The variation of exhaust emission levels with reduction of combustion noise is included.

The ever increasing motorization is entailing, apart from all its positive effects on our way of life, also some aftermaths detrimental to mankind. Air pollution and noises have become serious problems. More and more people are getting environment-minded and strongly expect that this annoyance be checked, at least kept in tolerable limits. Experts in all industrialized countries are engaged in controlling disturbing noises and there can be no doubt that internal combustion engines, automotive Diesel engines in particular, are producing no small share of this kind of nuisance. Intensive attention is therefore being paid to the silencing of noises lately. As far as mechanical engine noise is concerned the piston is a contributing element due to is side motion in the cylinder.

This paper describes a large indoor semi-anechoic facility for testing construction machines and discusses the procedures used to determine its acoustic performance characteristics. Data were obtained and analyzed employing controlled pure tone and broad band noise sources with varied microphone distances and elevations. The ground-plane microphone proved to be the most practical way to obtain representative data. Comparisons to an outdoor test site are included.

An analytical description of the sound pressure radiated aerodynamically by axial flow engine cooling fans is developed using semiempirical methods. Mathematical manipulation and digital computer techniques are employed to yield complete time and frequency sound pressure spectrums and overall sound pressure levels (unweighted and A-weighted). The mathematical tools are used to investigate the sound pressure characteristics of fans constructed with nonuniform blade spacing configurations. The theoretical analysis, which was verified experimentally, shows that the distribution of sound pressure in the frequency spectrum can be accurately predicted as a function of fan rotational frequency and blade spacing configuration. Fans with blade spacing configurations possessing a high degree of nonuniformity are shown to produce sound frequency spectrums which contain many discrete frequency components with similar magnitudes but with no outstanding discrete frequency components.

This report discusses some problems connected with the reduction of exhaust emissions and fuel consumption for direct injection Diesel engines; it indicates how they may be solved without modifying the basic power unit. The study was made on a standard production engine used in European heavy duty trucks. The effect of a number of individual variables was studied, including injection timing, injection rate, exhaust gas treatment (catalytic exhaust system), intake air pressure (including supercharging), charge dilution with exhaust gas recirculation, etc. After this first series of tests had been made, the effect of a combination of these variables was examined. To obtain the optimum results with a system providing a very fast injection rate, the effect of changes in the degree of turbulence was evaluated.

From engine test results, methods can be derived for reducing visible emissions of diesel engines, particularly under such operating conditions which so far are not yet subject to environment protection legislation. It is general practice today when starting diesel engines, to inject excess fuel, i.e. an additional amount of fuel in excess of the full load quantity, independent of ambient and engine temperatures and regardless of whether this is necessary or not. It is demonstrated that excess fuel should only be injected when starting a cold engine at ambient temperatures below freezing point and that the quantity of excess fuel should increase with falling temperature, reaching its maximum at the minimum engine starting temperature. The excess fuel quantity injected can be controlled with the aid of a wax element, so that, when the engine is warm, only the full load fuel quantity is injected.