Showing papers on "Diesel engine published in 1987"

Heat insulation of combustion chamber walls ― a measure to decrease the fuel consumption of I.C. engines?

Abstract: Experimental investigations were made with a single-cylinder direct-injection Diesel engine with heat-insulated piston. The most important result is an inferior economy compared with the not insulated aluminum-piston engine. It was found that this phenomenon is not caused by neither a changed combustion process nor increased blowby nor different friction losses, but rather by a drastic increase of the heat transfer coefficient during the first part of combustion with increasing surface temperature. This is taken into account in a modified equation for the heat transfer coefficient. Cycle-simulations using this modified equation show that there is neither a gain in fuel economy of naturally aspirated nor of turbocharged nor of turbocompound Diesel engines with ''heat insulated'' combustion chamber walls.

Ceramic coatings for advanced heat engines - A review and projection

Abstract: This report assesses the current status and future potential for the application of ceramic coatings in advanced diesel and turbine engines A previous report describes the authors findings in greater detail Ceramics, in contrast with metals, generally exhibit better structural and thermal capabilities at high temperatures In general, ceramics are more resistant to creep, oxidation, corrosion, erosion, and wear, as well as being better thermal insulators The benefits of thermal barrier coatings on the hotter side of diesel or turbine engine components are well-documented, and thermal barrier coatings are one of several applications of ceramics that are being pursued actively for heat engines Ceramic coatings are being considered for diesel engine cylinder liners, piston caps, valve faces and seats, piston rings, and other parts and for turbine components such as combustors, blades, stators, seals, and bearings

Effect of Compression and Expansion on Instantaneous Heat Transfer in Reciprocating Internal Combustion Engines

Abstract: Instantaneous heat flux at the surface of a cylinder head in a motored diesel engine has been measured, at various speeds, using a fast-response surface thermocouple. Heat flux during compression w...

Fuel injection and combustion phenomena in a high speed DI diesel engine observed by means of endoscopic high speed photography

Abstract: After a short description of the Endoscopic High Speed Combustion Photography Technique used, the results obtained through observation of the following phenomena in a 0.5 litre HSDI Diesel engine are presented: the wall jet development and the role of swirl, the effect of wall temperature (cold and warm engine) on combustion development, and the effect of pilot injection on mixture formation and combustion. To document these phenomena, typical high speed films are presented supplemented by cylinder pressure, injector needle lift, rate of heat release, and light radiation (flame luminosity) intensity data recorded simultaneously by means of a digital acquisition system.

Process for the reduction of the ignition temperature of diesel soot

Abstract: This invention relates to a process for reducing the ignition temperature of diesel soot. The process comprises contacting a hot exhaust from a diesel engine, which exhaust contains diesel soot, with a catalytic composite. The composite comprises a particulate filter coated with a sulfur resistant refractory inorganic oxide selected from the group consisting of titania, zirconia, silica, silica-alumina and alumina which has been treated to be sulfur resistant, i.e. alumina treated with titania, zirconia, tungsten oxide, etc. This coated ceramic trap has deposited thereon at least one catalytic element or compound selected from the group consisting of Pt, Pd, and Rh.

Fuel sulfur reduction for control of diesel particulate emissions

Abstract: The impact of diesel fuel sulfur reduction on directly-emitted and secondary atmospheric particulate is evaluated by experiment and analysis. Experimental evidence shows that fuel sulfur conversion rate to particulate sulfate is linear down to zero sulfur level. Analysis shows that sulfur-derived particulate accounts for the vast majority of atmospheric particulate from diesel engines. Consequently, fuel sulfur reduction would have a far greater impact in reducing atmospheric particulate burden than any other diesel engine particulate control strategy.

Diesel Fuel Ignition Quality as Determined in a Constant Volume Combustion Bomb

Abstract: The ignition delay times of forty-two different fuels were measured in a constant volume combustion bomb. The measurements were performed at three different initial air temperatures using fuels ranging from the primary reference fuels for cetane rating to complex mixtures of coal-derived liquids. The ignition delay times were examined in terms of the classical definitions of the physical and chemical delay times. The previously used definitions were found to be inadequate, and new definitions have been proposed. The total ignition delay times were studied in the context of providing a means for rating the ignition quality of the fuels. Fuel ignition quality rating schemes are discussed, including one based on the current cetane number scale as well as one based on a new scale which includes a measure of the sensitivity of the various fuels to the air temperature.

Autoignition of Methanol and Ethanol Sprays under Diesel Engine Conditions

Abstract: Methanol and ethanol are being considered as alternative fuels for diesel engines. One of the key concerns with using alcohol fuels in diesel engines is their poor ignition quality. This work presents the ignition characteristics of methanol and ethanol examined under simulated diesel engine conditions in a constant-volume combustion vessel. The ignition characteristics of isooctane and normal hexadecane (cetane) measured under the same conditions are also included for reference. Results show that to obtain ignition delays and rates-of-pressure-rise suitable for current diesel engine designs, methanol and ethanol require in-cylinder temperatures of about 1100 K at the time of injection. The results also show that the ignition delays of the alcohol fuels are independent of the chamber-pressure and are unaffected by the presence of 10% by volume of water in the fuel.

The Role of Lubricating Oil in Diesel Particulate and Particulate PAH Emissions

Abstract: The role of lubricating oil in total particulate emissions and in terms of polycyclic aromatic compounds (PAC) associated with the solvent organic fraction (SOF) of the particulate are investigated. Analysis of unused lubricating oil shows negligible concentrations of PAC. Used lubricating oil from a modified Perkins 4.236 Diesel engine, showed significant concentrations of PAC had accumulated in the oil in the form of PAC from unburnt fuel. Analysis of the oil was by gas chromatography using simultaneous parallel triple detection, allowing analysis of polycyclic aromatic hydrocarbons (PAH), nitrogen containing PAH (PANH) and sulphur containing PAH (PASH). Motoring the engine in the absence of fuel enable the contribution of lubricating oil to the exhaust particulate and particulate PAC emission to be determined. At high load and high speed the results indicated that the contribution of lubricating oil to the total exhaust particulate is over 40% and at low load and high speed reaches 70%. Analysis of the solvent organic fraction from the particulates using simultaneous parallel triple detection gas chromatography, revealed the presence of certain PAH which are also present in the lubricating oil. Thus the PAC content of the used oil acts as a source of PAC in particulate PACmore » emissions.« less

Direct fuel injection method for a diesel engine

Abstract: The invention relates to a direct fuel injection method for a diesel engine in which a preset quantity of fuel is introduced into a combustion space via a fuel injection nozzle in a preinjection and in a main injection which is separate from the preinjection. To achieve a short ignition delay with lowest possible specific fuel consumption during this process, the beginning of the preinjection occurs within the range of 10°-16° or of 20°-30° crank angle before top dead center, depending on speed, and the beginning of the main injection occurs within the range of 2° after top dead center to 15° before top dead center, the interval between the end of the preinjection and the beginning of the main injection being within the range of 3° to 14° or of 3° to 26° crank angle before top dead center and the preinjection quantity is 10% to 20% or 1% to 5% of the quantity of fuel preset in each case, depending on load.

Status Report on a Preliminary Survey of Strategies to Meet US-1991 HD Diesel Emission Standards Without Exhaust Gas Aftertreatment

Abstract: This paper presents a status report on a preliminary survey of strategies that might be employed to meet US-EPA 1991 heavy duty diesel emission standards without the use of a particulate trap. Although the survey of strategies is not yet complete, that portion dealing with the swirl supported diesel combustion process is sufficiently advanced to allow this status report to be published. It is anticipated that future related reports will provide a view of the complete survey, including quiescent combustion process. This report describes the techniques employed for the steady state approximation of the heavy duty transient test cycle and the analytical procedures used to characterize the particulate composition in terms of insolubles, and the fuel and lube oil related components.

Glow plug alternator control

Abstract: The present invention pertains to a control system for igniting devices (28,30,32,34,36,38) used in an internal combustion engine (24). In order to ignite alcohol fuel in a diesel engine, the fuel must be heated before or during compression. Glow plugs (28,30,32,34,36,38) conveniently provide heat, but have a short life in such continuous applications. Glow plugs must be accurately controlled to prevent overheating, which leads to open-circuiting. Individual constant voltage controls attempt to provide this function, but are only moderately successful. They are costly and complex, and provide only moderate protection from overheating. Since glow plug resistance correlates to glow plug temperature, resistance control provides better protection against glow plug overheating. Therefore, an apparatus (20) monitors the resistance of a single glow plug (28), and controls the resistance of each glow plug to a preselected resistance value. This preselected resistance value represents a glow plug temperature, that provides satisfactory fuel combustion combined with improved glow plug life. The principal use of the apparatus (20) of the present invention is with internal combustion engines using alternate fuels.

Exposure of Firefighters to Diesel Emissions in Fire Stations

Abstract: Personal sampling techniques were used to evaluate firefighter exposure to particulates from diesel engine emissions. Selected fire stations in New York, Boston and Los Angeles were studied. Firefighter exposure to total particulates increased with the number of runs conducted during an 8-hr period. In New York and Boston where the response level ranged from 7 to 15 runs during an 8-hr shift, the resulting exposure levels of total airborne particulates from diesel exhaust were 170 to 480 µg/m3 (TWA). Methylene chloride extracts of the diesel particulates averaged 24% of the total. The authors'findings suggest that additional research is necessary to assess fire station concentrations of vehicle diesel exhaust that may have adverse health consequences to firefighters.

Measurements of Instantaneous Heat Flux to Metal and Ceramic Surfaces in a Diesel Engine

Abstract: Mesure des flux thermiques instantanes a travers des parois en metal et en ceramique dans un moteur diesel

Sources of Hydrocarbon Emissions from a Small Direct Injection Diesel Engine

Abstract: The purpose of this paper is to clarify the mechanisms of unburnt hydrocarbon (HC) emissions from a small direct - injection (DI) diesel engine. HC emission levels of small DI diesel engines are considerably higher than those of corresponding indirect - injection (IDI) diesel engines, even when sacless injection nozzles that are effective in reducing HC emissions are installed on them. In this study, analytical engine tests were performed to evaluate the relative significance of various potential sources of HC emissions from a small DI diesel engine equipped with sacless type injectors. The results suggest the major sources of HC emissions to be 1) over-lean mixture formation beyond the lean limit of combustion during the ignition delay period, 2) spray impingement on the combustion chamber wall, the phenomenon of which may be closely related to the spray induction length, 3) spray droplets of relative larger size due to poor spray atomization in the final injection stage, and 4) flame quenching or incomplete combustion in the narrow clearance between the piston top and the cylinder head.

Combustion chamber importing system for two-cycle diesel engine

Abstract: A combustion chamber configuration and porting arrangement for a two-cycle crankcase compression diesel engine that improves scavenging. An exhaust port opens into one side of the engine cylinder bore and the scavenge ports and a precombustion chamber are configured so that they discharge their gases in an area diametrically opposed to the exhaust port for improving scavenging.

Low energy regeneration system for particulate trap for an internal combustion engine

Abstract: An apparatus for use with an internal combustion engine such as a diesel engine which emits hydrocarbons and particulates is disclosed. The apparatus is for use with an engine having a primary exhaust conduit, a flow divider defining parallel exhaust conduits connected to the primary exhaust conduit, and a pair of particulate traps, one each disposed in each of the parallel exhaust conduits and each of said traps having a frontal face exposed to the exhaust gas flow and one of the parallel exhaust conduits. The apparatus comprises (a) a heat exchange means disposed in the primary exhaust conduit for reducing the temperature of the exhaust gases for promoting partial condensation of hydrocarbons; (b) syphon means to conduct a separate syphoned flow of exhaust gas from the primary exhaust conduit around the heat exchanger to the frontal face of each of the traps; (c) a pair of valves, each responsive to a pressure differential between the primary exhaust conduit and a different parallel exhaust conduit to separately control each flow of the exhaust gas through said syphon means; (d) flow control means for selectively promoting pressure differential between one of the parallel exhaust conduits and a primary exhaust conduit while dissipating any significant pressure difference between the primary exhaust conduit and the other parallel exhaust conduit; and (e) means to augment the heat of the syphoned exhaust gas to facilitate ignition of the collected particles at the frontal face of a trap exposed to such exhaust gas.

Soot filter for a diesel engine

Abstract: A soot filter for diesel engines is described, having an inlet for introduction of exhaust gases, an outlet and a filter zone situated between inlet and outlet, which filter zone is provided with a multiplicity of tube-shaped porous ceramic filter cartridges or filter cylinders, through the cylindrical walls of which the exhaust gas enters radially and through the axial inner space of which the exhaust gas leaves axially, the ends of the filter cartridges or filter cylinders being elastically mounted and sealed radially by means of a casing of metal knitted fabric, metal honeycomb, metal netting or metal mesh and axially by means of a disc.

Experimental and Analytical Study of Heat Radiation in a Diesel Engine

Abstract: An experimental study was conducted of the heat radiation in a single-cylinder direct injection 14 iota engine. The engine was operated at speeds ranging from 1000 to 2100 RPM and a variety of loads. The radiation was measured using a specially designed fiber optics probe operating on the two-color principle. The probe was located in the head at two different locations: in one location it faced the piston bowl and in the other it faced the piston crown. The data obtained from the probe was processed to deduce the apparent radiation temperature and soot volume concentration as a function of crank angle. The resultant profiles of radiation temperature and of the soot volume concentrations were compared with the predictions of a zonal heat radiation model imbedded in a detailed two-zone thermodynamic cycle code.

Cylinder wear mechanism in an EGR-equipped diesel engine and wear protection by the engine oil

Abstract: Piston ring moving zone in the cylinder is one of the most critical lubrication regimes in diesel engines. This area is susceptible to combustion substances. In particular, abnormal wear is occasionally detected due to Exhaust Gas Recirculation (EGR) system equipment. In Japan, NO/sub x/ emission requirements for passenger car diesels have become more stringent effective October 1, 1986. OEMs tend to apply EGR systems to reduce NO/sub x/ in exhaust gas. In order to identify the phenomenon of abnormal cylinder wear of EGR equipped engine, engine bench tests were conducted under varied conditions in EGR equipment, cooling water temperature and fuel sulfur content. The test results suggest that wear caused at low temperature is mainly corrosive wear attributable to sulfuric acid formed by reaction with fuel sulfur and condensed water. Engine oil additives behavior against sulfuric acid was studied for control of corrosive wear and excellent CD 10W-30 engine oil was developed by selection of additives from the viewpoint of capability to neutralize sulfuric acid. The developed product demonstrated very good wear protection performance in the bench tests using EGR equipped engines.

Dual mode diesel electric power system for vehicles

Abstract: A diesel-electric propulsion and operating system may be used alone or in combination with another power supply. It has particular application to a dual mode, trolley and diesel bus. The diesel engine is controlled to supply only that power demanded by the electrical systems, including the traction motor, and to operate on a fixed power curve. This provides an optimized efficiency. Other novel characteristics include a two-speed drive axle limited to the mode selector, a backup hydraulic motor and pump, a dual mode passenger compartment tester, and a diesel engine pretester.

Diesel unit fuel injector with spill assist injection needle valve closure

Abstract: A diesel unit fuel injector includes a pump assembly having an externally actuated pump plunger (4) reciprocable in a bushing (3) which with the pump plunger defines a pump chamber (14), with flow therefrom during an injection cycle portion of the pump stroke being directed to a fuel injection nozzle assembly. The injection nozzle assembly includes a needle type differential area injection valve (91) that is normally biased to a valve closed position by a valve return spring (97) which is positioned in a spring cavity (103) and which is operatively connected to the opposite end of the needle injection valve. Passage means (51,37,102), including orifice passages (100,101), are used to direct spill flow from the pump chamber at the end of an injection cycle to the spring cavity to effect closure of the needle injection valve at a valve closing pressure which is greater than the valve opening pressure so that the pressure of the discharge of fuel at the end of an injection cycle is relatively great whereby to effect increased penetration of the discharged fuel into the associate combustion chamber of a diesel engine.

Method and apparatus for filtering solid particulate matter from diesel engine exhaust

Abstract: An improved method for removing solid particulate matter from the exhaust of a diesel engine, having the steps of passing the engine's exhaust flow through at least a part of filter means to trap solid particulate matter contained initially in the exhaust, thereby to remove said matter from said exhaust flow, periodically interrupting the exhaust flow through at least said part of the filter means, passing, during said interruption, at least one backflush fluid pulse through at least said part of the filter means thereby to dislodge from the filter means, and entrain, said solid particulate matter, and transporting said dislodged solid particulate matter to the intake of said engine so that said matter can be combusted in the engine, wherein the improvement comprises purge means advantageously positioned so as to allow the discharge of noncombustible particulate matter from the engine before it accumulates to a harmful level.

Diesel engine equipped with a mechanically driven charger

Abstract: A diesel engine comprising an intake passage in which a turbocharger and a mechanically driven charger are arranged. A bypass passage bypassing the mechanically driven charger is provided, and a bypass valve is arranged in the bypass passage. When the engine is started, the mechanically driven charger is operated and the bypass valve is closed. When the engine is operating under a partial load after completion of the warm-up of the engine, the operation of the mechanically driven charger is stopped and the bypass valve is opened.

Direct analysis of diesel particulate-bound hydrocarbons by gas chromatography with solid sample injection

Abstract: Particulate-bound hydrocarbons emitted by diesel engines have been analysed using a rapid new technique. The method involves directly loading filter-borne particulate into a modified injection port of a gas chromatograph. Hydrocarbons are vaporized in this solid sample injection system and subsequently become adsorbed on to a chromatogaphy column. The merits of this procedure are demonstrated by comparing results with those obtained using conventional gas chromatography (with liquid injection) and thermogravimetry. The contribution of unburned engine oil to diesel particulate emissions has been investigated using the new method. For a DI truck diesel engine operated over the U.S. Federal Heavy Duty Transient Cycle it is shown that 40% of the particulate appears to be derived from unburned oil. For a comparable IDI truck diesel engine this value was 28%.

Supercharged marine diesel engine

Abstract: In a supercharged marine diesel engine having at least one exhaust-gas turbocharger (6, 7) and a separate utility turbine (12) which is connected in parallel with the supercharging turbine (7) and delivers power, and having at least one auxiliary diesel engine (10) which is supercharged by means of a turbocharger and which drives a synchronous generator (11) supplying the ship's electrical system with electrical energy, the utility turbine (12) is coupled to a free shaft end of the auxiliary diesel/generator unit (10, 11). In this way, the auxiliary diesel engine (10) can be relieved of load, which results in a considerable fuel saving. In order to maintain a positive scavenging gradient when the auxiliary diesel engine (10) is relieved of load, a small portion of the exhaust gases of the marine diesel engine (2) is conveyed to a point upstream of the supercharging turbine (19) of the auxiliary diesel engine (10).

Characteristics of Diesel Soot Suppression with Soluble Fuel Additives

Abstract: Experiments on a large number of soluble fuel additives were systematically conducted for diesel soot reduction. It was found that Ca and Ba were the most effective soot suppressors. The main determinants of soot reduction were: the metal mol-content of the fuel, the excess air factor, and the gas turbulence in the combustion chamber. The soot reduction ratio was expressed by an exponential function of the metal mol-content in the fuel, depending on the metal but independent of the metal compound. A rise in excess air factor or gas turbulence increased the value of a coefficient in the function, resulting in larger reductions in soot with the fuel additives. High-speed soot sampling from the cylinder showed that with the metal additive, the soot concentration in the combustion chamber was substantially reduced during the whole period of combustion. It is thought that the additive acts as a catalyst not only to improve soot oxidation but also to suppress soot formation. Furthermore, the additives resulted in decreased ignition temperatures and enhanced oxidation of the additive-containing soot.