Showing papers on "Diesel engine published in 1993"

Sources of fine organic aerosol. 2. Noncatalyst and catalyst-equipped automobiles and heavy-duty diesel trucks

Abstract: Gasoline- and diesel-powered vehicles are known to contribute appreciable amounts of inhalable fine particulate matter to the atmosphere in urban areas. Internal combustion engines burning gasoline and diesel fuel contribute more than 21% of the primary fine particulate organic carbon emitted to the Los Angeles atmosphere. In the present study, particulate (d[sub p] [le] 2 [mu]m) exhaust emissions from six noncatalyst automobiles, seven catalyst-equipped automobiles, and two heavy-duty diesel trucks are examined by gas chromatography/mass spectrometry. The purposes of this study are as follows: (a) to search for conservative marker compounds suitable for tracing the presence of vehicular particulate exhaust emissions in the urban atmosphere, (b) to compile quantitative source profiles, and (c) to study the contributions of fine organic particulate vehicular exhaust to the Los Angeles atmosphere. More than 100 organic compounds are quantified, including n-alkanes, n-alkanoic acids, benzoic acids, benzaldehydes, PAH, oxy-PAH, steranes, pentacyclic triterpanes, azanaphthalenes, and others. Although fossil fuel markers such as steranes and pentacyclic triterpanes can be emitted from other sources, it can be shown that their ambient concentrations measured in the Los Angeles atmosphere are attributable mainly to vehicular exhaust emissions. 102 refs., 9 figs., 6 tabs.

Multidimensional Modeling of Diesel Ignition and Combustion Using a Multistep Kinetics Model

Abstract: Ignition and combustion mechanisms in diesel engines were studied using the KIVA code, with modifications to the combustion, heat transfer, crevice flow, and spray models. A laminar-and-turbulent characteristic-time combustion model that has been used successfully for spark-ignited engine studies was extended to allow predictions of ignition and combustion in diesel engines. A more accurate prediction of ignition delay was achieved by using a multistep chemical kinetics model. The Shell knock model was implemented for this purpose and was found to be capable of predicting successfully the autoignition of homogeneous mixtures in a rapid compression machine and diesel spray ignition under engine conditions. The physical significance of the model parameters is discussed and the sensitivity of results to the model constants is assessed. The ignition kinetics model was also applied to simulate the ignition process in a Cummins diesel engine. The post-ignition combustion was simulated using both a single-step Arrhenius kinetics model and also the characteristic-time model to account for the energy release during the mixing-controlled combustion phase. The present model differs from that used in earlier multidimensional computations of diesel ignition in that it also includes state-of-the-art turbulence and spray atomization models. In addition, in this study the model predictionsmore » are compared to engine data. It is found that good levels of agreement with the experimental data are obtained using the multistep chemical kinetics model for diesel ignition modeling. However, further study is needed of the effects of turbulent mixing on post-ignition combustion.« less

How do diesel-fuel ignition improvers work?

Abstract: An important descriptor of diesel fuel is its Cetane Number: this is an indicator of the time delay between injection and spontaneous ignition of fuel in a standard diesel engine running under specified conditions; the shorter the ignition delay, the higher the cetane number. Thus, those groupings of atoms within a hydrocarbon molecule that are beneficial in conferring a resistance to spontaneous ignition in a gasoline, i.e. a high octane number, are undesirable when they occur in a diesel fuel, and vice versa. The cetane number scale uses two standard compounds, cetane (n-hexadecane) defined as 100, and heptamethyl-nonane defined as 15, so that, assuming linear mixing, a 1:1 mixture would have a cetane number of 57.5, a 1:2 mixture would have one of 43.3, &c. Long-chain paraffins tend to have high cetane numbers, e.g. n-dodecane = 80, n-tridecane = 83, in addition to cetane itself = 100. On the other hand, hydrocarbons containing benzene rings tend to have very low cetane numbers, e.g. diphenyl = 21, diphenylmethane = 11 and 1,2-diphenyl-ethane = 1. Extremely low cetane numbers are also found for hydrocarbons with a benzene ring carrying short-chain substituents, e.g. xylene = –10 and m-di-iso-propyl-benzene = –12, but as the side chain becomes longer, the cetane number rises, to 26 for n-hexyl-benzene and to 50 for n-nonyl-benzene. Substances containing fused rings also exhibit very low cetane numbers, e.g. α-methyl-naphthalene = 0. A corollary is that the minimum spontaneous ignition temperatures for aromatic hydrocarbons are higher than for non-aromatics. Legislated National Standards usually require that the cetane number of commercial diesel fuel shall exceed a certain value, say 40. Most diesel engines do not perform well with fuels of cetane number below this: for

A particulate and exhaust gas emission control system

Abstract: A particulate and exhaust emission control system for a vehicle (10) having a diesel engine (12). The control system has a particulate trap (24) connected to the exhaust manifold (22) of the diesel engine, an additive tank (30) for storing a fuel additive decomposed by the engine's combustion process to form a reducible metal oxide capable of depressing the ignition temperature of the carbon particulates collected by the particulate trap (24) and a metering mechanism (34) responsive to the adding of diesel fuel to the vehicle's fuel tank (28) to add a quantity of the fuel additive to the diesel fuel in the fuel tank (28) to maintain a predetermined ratio of the fuel additive to the diesel fuel in the tank. The metal oxide depressing the ignition temperature of the carbon particulates collected by the particulate trap (24) to a temperature obtained by the particulate trap during selected operating parameters of the diesel engine (12). The particulate trap (24) includes a honeycomb ceramic filter element (38) having inlet channels (44) for collecting the carbon particulate and exit channels (46) coated with a catalyst to oxidize carbon monoxide and unburned hydrocarbons in the exhaust.

Diesel engine exhaust gas recirculation system for NOx control incorporating a compressed air regenerative particulate control system

Abstract: A diesel engine exhaust gas recirculation system for control of NO x emissions is disclosed in hi h total particulate (soot, condensed polynuclear aromatic and aliphatic hydrocarbons, and ash) control system is employed to filter the exhaust gas prior to reintroduction to the diesel engine. By cleaning the recirculated exhaust gas of substantially all particulates, wear on the engine due to particulate abrasion is minimized, and NO x and particulate emissions are reduced. The particulate control system includes a high efficiency ceramic monolith trap that is periodically regenerated by one or more pulses of high-pressure air that move in the opposite direction of the engine exhaust flow through the trap. In one embodiment, a portion of the filtered diesel exhaust is recirculated to the engine. In a further embodiment, the particulate control system filters a portion of the diesel exhaust in the recirculation flow path. The system can retrofit any existing diesel-powered equipment.

A large supercharged diesel engine

Abstract: Exhaust gas is in a supercharged internal combustion engine recycled from the high pressure side of the turbocharger to the charging air system of the engine At least part of the recycled exhaust gas is humidified to largely 100 percent relative humidity This on one hand cools the gas so that the temperature at initiation of the combustion in the engine cylinders is lowered, and on the other hand the heat capacity of the steam in the gas restricts the temperature raise occuring during the combustion These factors both act to reduce the amount of NOx produced by the combustion The addition of water is effected by a scrubber (16) which purifies the recycled gas A blower (17) augments the pressure of the recycled gas The scrubber may be made to generate fresh water by designing it with several stages where sea water is supplied to the first stage and fresh water to the last stage

Waste oil management system

Abstract: A fuel management system for blending of an alternative fuel such as waste oil with a conventional fuel and the continuous filtration thereof before delivery to fuel injection system of a conventional diesel engine. The system attaches to the storage tanks of a heavy duty truck using a proportioning device for withdrawing of the fuels from their respective tanks before blending by use of an air operated diaphragm transfer pump. The blended fuel is continuously recirculated through at least one fiberglass filter with a device for metering the final flow to the injection system and the remainder to the storage tanks. The system can remove up to 99.5 percent of the heavy contaminants found in the diesel fuel and alternative fuels.

Regenerable diesel exhaust filter and heater

Abstract: A filter assembly for removing particulates from the exhaust gas of a diesel engine. The filter assembly includes a housing having an inlet pipe which may be coupled to the engine and an outlet pipe which may be open to the atmosphere, and a self-contained filtering mechanism disposed within the housing. An exhaust gas fluid path is defined from the inlet pipe through the self-contained filtering mechanism and out the outlet pipe. Each of the components of the self-contained filtering mechanism are highly resistant to high temperatures, so that the filtering mechanism may be electrically regenerated by heat, produced by a heater operatively associated with the filtering mechanism, which burns off accumulated, typically hydrocarbon, particulates.

Apparatus for purifying exhaust gas of diesel engine

Abstract: Apparatus for purifying exhaust gas from a diesel engine (1) comprises a wall-flow filter (3) made of a porous ceramic material for capturing carbon components contained in the exhaust gas and burning up the captured carbon components, a first exhaust pipe (2) for introducing the exhaust gas into the filter (3), a second exhaust pipe (4) for introducing the exhaust gas purified by the filter (3) a bypass pipe (6) bypassing the filter (3), first (8) and second (9) valves arranged inside of the first (2) and bypass (6) pipes, respectively, for controlling the exhaust gas flow, a heater (17) for burning up carbon components captured in the filter (3), first (13) and second (14) temperature sensors for detecting temperatures in the first pipe (2) and the filter (3), respectively, and a controller (7) for controlling opening and closing of the first (8) and second (9) valves based on the temperature difference between temperatures detected by first (13) and second (14) temperature sensors to prevent the filter (3) from cracking.

Availability accumulation and destruction in a DI diesel engine with special reference to the limited cooled case

Abstract: This work develops a method for the calculation of both the irreversibility produced during combustion and the working medium availability at the end of the expansion process in a high speed, direct injection (DI), naturally aspirated, four-stroke diesel engine, on which experiments were conducted at the authors' laboratory. The experimental data were processed for the determination of fuel reaction rates; the combustion irreversibility production rate was then computed from the fuel reaction rates via an analytical mathematical expression which was developed by the present research group, based on the combined resolution of the first and second laws of thermodynamics. This expression is coupled with standard first law calculations and then is integrated to give the accumulated combustion irreversibility, while the working medium availability variation is also computed throughout the engine closed cycle. These calculations are applied for a wide range of measured loads, injection timings and engine rotational speeds; they are also expanded in the direction of the intensity of the rate of heat transfer loss (to the engine cooling medium) for every combination of the experimentally determined engine variables. Therefore, apart from investigating the effect of various operating parameters on the availability balance, it is possible to evaluate the effect of the engine heat transfer reduction (limited cooled engine), from the second law analysis point of view, on the potential for efficiency improvements made by using the increased exhaust heat in recovery devices (e.g. the exhaust turbine or Rankine bottoming cycle compounding). With the present second law analysis, which forms the spearhead of this work, the exhaust gas availability offers more useful information than its enthalpy counterpart (first law analysis) for the operation of such compounding devices. The irreversibility calculation also provides useful information for the combustion loss, which cannot be isolated and evaluated at all by a first law analysis.

Supplemental gaseous fuel system for a diesel engine

Abstract: A supplemental gaseous fuel system is provided for retrofit to an existing diesel engine having a conventional load sensitive speed control. The supplemental gaseous fuel system operates independently of the load sensitive speed control thus enabling the diesel fuel supply system to rapidly react to load transients. A control system senses a physical position of an actuator mechanism in the diesel fuel injector pump and opens and closes a buffer valve in response to predetermined positions of the actuator. In normal operation of the engine, variations (increases) in engine load are initially corrected for by an immediate but momentary increase in diesel fuel to the engine. However, as soon as the engine has responded to the increase in diesel fuel and increased its rate of combustion, the gas flow to the engine is increased and causes the diesel fuel actuator to approach a minimum fuel setting.

A rapid test to measure performance, emission and wear of a diesel engine fueled with palm oil diesel

Abstract: Results of performance, emission and tribological evaluations of palm oil methyl ester and its blends with conventional diesel in an automobile diesel engine test bed are presented Polymerization and carbon deposits on the fuel injector were monitored CO, CO2, O2, combustion efficiency and temperature of exhaust gases were also measured Palm oil methyl ester and its blends have great potential as alternative diesel fuel Performance and exhaust gas emission for palm oil methyl ester and its blends with conventional diesel are comparable with those of conventional diesel fuel Palm oil methyl ester does not pose a severe environmental problem and will not deteriorate engine and bearing components

Method and device for determining the load condition of particle filters

Abstract: A method and a device for determining the load condition of a particle filter (10) used in the exhaust gas system (11) of a diesel engine (12) employed in particular in a motor vehicle, wherein a pressure value (ΔP filter , P abs .pre-filter or P rel .pre-filter) and a temperature value (t m ,filter of the exhaust gas volume flow in the particle filter (12) are measured; the engine speed (n) proportional to the volume flow is measured; an actual characterizing value is calculated considering these measurement values; and a comparison between actual characteristic value (IK) and limit characteristic value (GK) is performed for initiating a regeneration process when the difference (DI) is sufficiently small.

Engine Knock Rating of Natural Gases—Methane Number

Abstract: A procedure has been developed and documented for determining the methane number of gaseous fuels. The methane number provides an indication of the knock tendency of the fuel. An experimental test matrix was designed for quantifying the effects of ethane, propane, butane, and CO[sub 2]. A unique gas mixing and control system was developed to supply test gases to the engine and to control the equivalence ratio and engine operation. The results of the experiments agreed well with the limited data published in the literature. Predictive equations were developed for the methane number (MN) of gaseous fuels using the gas composition. The forms of these equations are suitable for incorporation in a computer program or a spread-sheet.

Fuel injection controller for use in an internal combustion engine

Abstract: A diesel engine has a fuel injection nozzle to which pressurized fuel is supplied from a pump. The nozzle has a pressure sensor detecting the fuel pressure and a lift sensor sensing a lift magnitude of a needle valve. An electronic control unit (ECU) computes a variation ratio of the fuel pressure value which is measured by the pressure sensor. The ECU computes a non-increasing point in an increasing part of variation ratio and judge the point to be a timing for starting the fuel injection of the nozzle. The EPU also computes the actual fuel injection amount in accordance with the fuel injection timing as well as the fuel pressure and the lift amount of the needle valve both at the various points. The EPU control the actual injection amount to be identical to a target fuel injection amount.

Thermal barrier coating development for diesel engine aluminum pistons

Abstract: Specific outputs of some diesel engine applications have produced thermal loadings in excess of the strength of typical aluminum-piston alloys. Thermal barrier coatings are being evaluated to return the component durability to acceptable levels, as well as providing a means of lowering heat rejection. This paper discusses the use of a finite element model to analyze these thermal barrier coating systems, including the impact of material properties, coating thickness, residual stress and boundary conditions. Given the resulting predicted temperatures and stresses, together with material strength information, the primary cause of coating failure is proposed to be low cycle fatigue resulting from localized yielding when the coating is hot and in compression. This has been confirmed with engine testing.

Low emissions diesel fuel

Abstract: A low emissions diesel fuel with prescribed levels of aromatics and cetane number is disclosed which, when combusted in a diesel engine, results in lower emissions than the California Reference diesel fuel.

Diesel engine EM actuated fuel metering valve controller - has current sensor feeding back information to controller to determine on and off switching points of valve

Abstract: The valve is used for precise metering control of fuel supplied to a diesel engine. A fuel management controller (100) provides a control signal to operate a FET device to activate a metering valve. This moves a needle to open or close a flow orifice. The current applied to the actuator is monitored and fed back to the controller to allow the switching points of the valve to be accurately determined. The current cycle is determined by the applied voltage pulse. At a specific point a transition occurs to initiate the time point at which the max. valve opening occurs. A similar interpretation of the current cycle allows the closing time to be determined. USE/ADVANTAGE - Simplified operating point determination. Fewer components required.

Laser-induced-fluorescence imaging of NO in an n-heptane- and diesel-fuel-driven diesel engine

Abstract: Continuous on-line imaging by 2D-LIF techniques of in-cylinder NO distributions in a running Diesel engine is explored using an ArF-excimer laser at 193 nm operating at low power. For the first time NO excitation spectra could be measured as a result of high optical transparencies during measurements over longer periods of time. The averaged distributions show different combustion behaviour of both fuels proving the potential of the 2D-LIF technique in application to non-intrusive combustion diagnostics in a steady running Diesel engine.

Controlled fuel injection rate for optimizing diesel engine operation

Abstract: Fuel delivery system for internal combustion engines and method of delivering fuel by the automatic selection and use of different sections of the fuel pumping ramp of a cam mechanism within the system to control the rate of fuel injection by varying and shaping injection pressure waves or pulses to match engine air intake flow for different engine speed and load conditions. A solenoid operated fuel delivery valve is employed for controlling fuel timing and quantity by commands from a microprocessor with inputs which includes torque demand, engine speed, cam mechanism position and solenoid current regulator signals.