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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.

September 17-19, 2019 │ Garden Grove, CA, USA

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

September 17-19, 2019 │ Garden Grove, CA, USA

The EU Commission's “Clean Power for Transport” initiative aims to break the EU's dependence on imported oil whilst promoting the use of alternative fuels to reduce greenhouse gas emissions. Among the options considered is the use of liquefied natural gas (LNG) as a substitute for diesel in long haul trucks. It is interesting to ask how the lifecycle greenhouse gas (GHG) emissions of LNG compare with conventional diesel fuel for this application. The LNG available in Europe is mainly imported. This paper considers the “well-to-tank” emissions of LNG from various production routes, including: gas production, treatment and liquefaction, shipping to Europe, terminal, distribution and refuelling operations. “Tank-to-Wheel” emissions are considered for a range of currently-available engine technologies of varying efficiency relative to diesel.

Wear characteristics of four bearing materials have been investigated under different sliding conditions. The bearing materials used were CDA 954, CDA 863, CDA 932, and CDA 938. Using a Taber Wear Tester, a cylinder on a flat geometry was used as a tribo contact pair. All bearing materials in the form of a thick cylindrical disk were subjected to combined sliding-rolling motion against a rotating flat disk. The flat disk was either an abrasive disk, or a very soft steel disk, or a hardened steel disk with and without lubrication. Wear was measured as weight loss after several thousand cycles of rotation. Maximum wear of the bearing materials occurred when the counter body was a very soft steel disk. These results together with the wear rate of each bearing material sliding against four different counter bodies are presented. These results are found to be of practical importance in the design and application of journal bearings made of materials used in this investigation.

Axial piston type pumps are often exposed to severe operating conditions because of the duty cycle, the environment, or, in some situations, poor maintenance and even abuse. The detrimental effects on the pump and the hydraulic system as a result of these adverse conditions are often not known or predictable. In this study, four controlled severe operating conditions were imposed on four identical axial piston type pumps. They included 1) constant high load pressure and normal fluid temperature, 2) constant high load pressure and elevated fluid temperature, 3) cyclic load pressure and normal fluid temperature, and 4) cyclic load pressure and elevated fluid temperature. The tests were long-term; they were run continuously for up to 5000 hours. The pump wear was monitored in all cases using ferrography. In addition, the condition of the fluid was monitored and the circuit filters were examined periodically. The results of the findings are presented in this paper.

The exhaust valve system of combustion engines experiences a very complex contact situation of frequent impact involving micro sliding, high and varying temperatures, complex exhaust gas chemistry and possible particulates. The wear rate has to be extremely low, and the individual wearing events operate at a scale that is very demanding to detect. The tribological conditions in the exhaust valve system are expected to become even worse for engines that will follow the future emission regulations. The regulations demand reduced amounts of soot and particles, sulfur compounds, etc., which today act beneficial for the seating surfaces. The reductions are expected to increase the metal-to-metal contact.

This study investigates the wear characteristics of a variable valve timing (VVT) system used to vary the phasing of the inlet valve events on a medium speed marine diesel engine. The running-in properties of critical components within the system are examined. The effect of surface finish and surface hardness upon wear is examined. It was found that in order to prevent excessive wear between the roller and tappet follower then the roller should be harder than the tappet. Tappet and roller hardness values of 60 and 70 Rockwell Hardness ‘C’ (HRC) respectively were found to be satisfactory.

With increasing interest in more biodegradable and fire-resistant hydraulic fluids and with the availability of water-glycol hydraulic fluids suitable for high-pressure hydraulic pump operation, there is increasing interest in the conversion of mineral oil hydraulic systems to these alternative fluids. In this paper, the proper conversion procedures and troubleshooting of some common causes of hydraulic failures for the conversion of mineral oil hydraulic fluids to a water-glycol will be reviewed.

Hydraulic fluid performance, including water-glycols (W/G), is dependent on the chemical composition of the fluid and cleanliness. An overview of W/G fluid chemistry on pump wear is provided here. Also provided, is a brief overview of the impact of fluid cleanliness on the potential wear properties of various components. Finally, an overview of recommended analytical procedures to assure adequate long-term fluid hydraulic and lubrication performance is provided. If these procedures are followed, substantial improvements in hydraulic pump longevity and performance will be realized.

One of the most commonly used tests to evaluate the antiwear properties of a hydraulic fluid is ASTM D 2882 which is based on a Vicker's V-104 vane pump. Although this is a commonly used test, the results are subject to numerous potential problems in both testing procedure and pump hardware. In this paper, the particular focus will be placed on potential problems that may be encountered with testing of water-glycol hydraulic fluids which may lead to erroneous and non-reproducible results.

Separation of water from vegetable oil base stocks for environmentally acceptable tractor/hydraulic fluids was studied. Mixtures of canola, a representative vegetable oil, with mineral oil and three synthetic esters were emulsified and allowed to separate. In additional work, hydrogen bonding interfering compounds, alcohols and nitrogen containing compounds, were added to base stocks and finished fluids to improve the water rejection properties. Two of the synthetic esters were found to improve water rejection in economical concentrations, while the other formed a stable emulsion with the vegetable oil and water. The mineral oil tested formed a stable water-in-oil emulsion with low concentrations of canola oil, then reacheed a maximum rejection concentration as the canola increased, since canola forms a oil-in-water emulsion. The hydrogen bonding inhibitors worked with base stocks but were not helpful when the additive package was included.

Measuring water quality and preventing drawbacks caused by deteriorated water quality in tap water fluid power systems is a unique problem. Tap water is a suitable environment for waterborne microorganisms. It also contains dissolved and undissolved organic and inorganic matter. Wear particles in the tap water fluid power systems are a separate problem, however closely linked to problems above mentioned. Contamination and the quality of the pressure medium in the system is a function of local characteristics of tap water, operating parameters, system and component design and contamination introduced to the system. To study effects of water quality on tap water fluid power systems, and to evaluate methods for measuring water quality and particle counting, a pilot scale hydraulic system was constructed. The pilot scale system emulates typical operation of a commercial tap water fluid power system.

An increase in global oil consumption, coupled with a peak in oil production, has seen the price of fuel escalate in recent years, and consequently the transport sector must take measures to reduce fuel consumption in vehicles. Similarly, ever-tightening emissions legislation is forcing automotive manufacturers to invest in technology to reduce toxic emissions. In response to these concerns, this project aims to address one of the fundamental issues with the Internal Combustion Engine - approximately one third of the fuel energy supplied to the engine is lost as heat through the exhaust system. The specific aim of this project is to reduce the fuel consumption of a diesel-electric hybrid bus by recovering some of this waste heat and converting it to useful power. This report details how turbocompounding can be applied to the engine, via the inclusion of a turbogenerator, and assesses its waste heat recovery performance.

Few previous publications investigate the possibility of combining multiple waste heat sources in a combustion engine waste heat recovery system. A waste heat recovery system for a HD truck diesel engine is evaluated for utilizing multiple heat sources found in a conventional HD diesel engine. In this type of engine more than 50% of heat energy goes futile. The majority of the heat energy is lost through engine exhaust and cooling devices such as EGRC (Exhaust gas recirculation cooler), CAC (Charge air cooler) and engine cooling. In this paper, the potential of usable heat recuperation from these devices using thermodynamic analysis was studied, and also an effort is made to recuperate most of the available heat energy that would otherwise be lost. A well-known way of recuperating this heat energy is by employing a Rankine cycle circuit with these devices as heat sources (single loop or dual loop), and thus this study is focused on using a Rankine cycle for the heat recovery system.

The use of reciprocating internal combustion engines (ICE) dominates the sector of the in-the-road transportation sector, both for light and heavy duties. CO2 reduction is the technological driver, considering the severe worldwide greenhouse commitments. In ICE more than one third of the fuel energy used is rejected to the environment as thermal waste through the exhaust gases. Therefore, a greater fuel economy could be achieved, recovering this energy and converting it into useful electric power on board. Financial benefits will be produced in terms of fuel cost which will rebound similar benefits in terms of CO2 emitted. For long hauling vehicles, which run for thousands of miles, frequently at fixed engine operating conditions, this recovery appears very worthy of attention. In this activity, an ORC-based power unit was designed, built and tested fed by a heavy duty diesel engine, so contributing to the huge efforts on going in that specific sector.

NEARLY 300 fleet operators were questioned by Mr. Laurie to gather data for this paper on what features the users of trucks would like to have the manufacturers incorporate in post-war trucks. The cooling system is one important item that came in for its share of criticism. For example, maintaining the proper coolant level is most important, and yet many of today's systems require filling into the filler neck before the liquid level can be seen. Petcocks or sight gages properly installed could solve this problem, according to Mr. Laurie. Accessibility for maintenance should also be improved in the post-war truck. Some of today's trucks have batteries that are not located for ease of servicing and spark plugs that it is almost impossible to remove and replace. Improvements should also be possible in cold starting of the engine, based on the experience of the Army in cold climates.