Fuel Line Pressure Research Articles

The Combustion and Emission Characteristics of Corn Oil Biodiesel with Titanium Oxide (TiO2) Nano-additive

This experiment produced biodiesel from corn oil through transesterification. Fuel mixture proportions were changed to assess engine performance and reduce fossil fuel emissions. This study examined brake power, mean effective pressure, mechanical efficiency, brake thermal efficiency and indicated thermal efficiency, and emissions such as hydrocarbons, carbon monoxide and NOx. 20% of corn oil was blended with diesel to make biodiesel. The fuel characteristics of the corn oil methyl ester matched ASTM standards. Experimental results were obtained by operating a single-cylinder four-stroke diesel engine under various load conditions. Titanium oxide nanoparticles in the biodiesel reduced HC and CO engine emissions whereas, there was an increase in CO2 and NOx emissions. Combustion parameters such as cumulative net heat release rate and fuel line pressure decreased whereas, cylinder pressure and net heat release rate increased; the sample BD20 + 100 ppm TiO2 sample exhibited appreciable results.

Technical Feasibility of Dimethyl Ether-Fueled Mechanical Fuel Injection System-Equipped Multicylinder Compression Ignition Engine

Abstract This experimental study evaluated the combustion and performance characteristics of a 100% dimethyl ether (DME)-fueled multicylinder compression ignition engine equipped with a customized mechanical fuel injection system. The engine operating envelope covered different engine loads and speeds. The effect of DME's physicochemical properties, such as density, compressibility, and latent heat of vaporization, on the engine combustion and performance characteristics was analyzed under varying engine loads and speeds. The DME-fueled engine exhibited an average of >8% higher brake thermal efficiency than the baseline diesel-fueled engine. DME's lower brake-specific energy consumption indicated that the DME-fueled engine efficiently converted fuel's chemical energy into mechanical energy compared to the baseline diesel-fueled engine. The in-cylinder pressure of DME was higher than that of the mineral diesel engine at low loads and lower at higher engine loads. DME engine exhibited extensive and reliable operating range and consistent performance. The mixing-controlled phase dominated the DME combustion. DME's higher compressibility led to a few distinct effects with respect to baseline diesel: (1) lower fuel line pressure in high-pressure fuel lines, (2) higher residual pressure oscillations due to higher compression energy stored in the high-pressure fuel lines, and (3) retarded actual injection timing. The variations in the engine speed showed a similar effect on DME's combustion and performance characteristics as baseline diesel. The DME-fueled engine's lower in-cylinder pressure, lower rate of initial pressure rise, and lower exhaust gas temperature indicate a lower heat rejection engine, delivering higher thermal efficiency.

Understanding the performance, emissions, and combustion behaviors of a DI diesel engine using alcohol/hemp seed oil biodiesel/diesel fuel ternary blends: Influence of long-chain alcohol type and concentration

In this study, it was aimed to examine the influences of biodiesel–diesel-higher alcohol (1-pentanol, 1-hexanol, and 1-heptanol) blends on the performance, emission and combustion behaviors of a single-cylinder diesel engine. The tests were performed at a fixed speed of 1500 rpm and variable loads (25%, 50%, 75%, and 100%). For the tests, 80% diesel and 20% hemp seed oil biodiesel were blended and called as B20. Biodiesel fuel was produced by transesterification from hemp seed oil in the presence of methanol and potassium hydroxide for the preparation of B20 binary test fuel and other ternary fuels. Furthermore, nine ternary blend fuels [20% HSOB + 70%, 60% and 50% diesel, respectively + 10%, 20% and 30% higher alcohol (pentanol, hexanol and heptanol) respectively] were prepared. The calculations made with the experimental data revealed that the minimum brake specific energy consumption values were 12,48 MJ/kW h, 13,06 MJ/kW h, 13,27 MJ/kW h, 13,35 MJ/kW h, 13,47 MJ/kW h, and 13,59 MJ/kW h, respectively, for diesel fuel at full load, for fuels B20, B20Hx10, B20Hp10, B20Hx20 and B20Pe10, the maximum brake thermal efficiency values were obtained as 28.85%, 27.56%, 27.14%, 26.97%, 26.73% and 26.49%, respectively, for the same fuels at the same load. The increment in higher alcohol concentration in the blend delayed start of combustion and therefore the ignition delay period was prolonged. In the fuel line pressure data, changes were observed depending on the amount, viscosity and density of the fuel. Furthermore, B20Hx10 and B20Hp10 fuels gave the maximum in-cylinder pressure, heat release rate, average gas temperature and pressure rise rate values after diesel and biodiesel. The addition of biodiesel and higher alcohol to diesel fuel resulted in a decrease in NOX, CO and unburned HC and smoke emissions and an increase in CO2. NOX, CO and unburned HC values of higher alcohol blended fuels at full load showed lower results, between 3.04–22.24%, 22.85–56.35% and 5.44–22.83%, respectively, compared to diesel fuel. It can be concluded that the use of hemp seed oil biodiesel and higher alcohol in the diesel engine will make a significant contribution to the reduction of NOX emissions.

Experimental study on fuel line pressure fluctuation of biodiesel–DME blends in a common-rail injection system

The fuel line pressure fluctuations at the injector outlet of biodiesel–dimethyl ether (DME) blends in a common-rail injection system are investigated using the wavelet packet transform. The effects of injection condition and DME blending ratio on the pressure fluctuation characteristics are determined. The results show that the pressure fluctuation intensity determines wavelet packet energy distribution in the three subsignals. The overall pressure fluctuation is reflected by subsignal Sig1, which is composed of subsignals Sig2 and Sig3. Sig2 exhibits medium-frequency pressure fluctuations, and mainly occurs in the pressure rise stage and the pressure drop stage. Sig3 exhibits high-frequency pressure fluctuations, and mainly locates in the pressure stabilization stage. The pressure fluctuations at high injection pressure are more significant compared with those at low injection pressure. Biodiesel–DME blends display similar effects of injection pressure. With the increase of injection pressure, the mean energy and the standard deviation of Sig1, Sig2, and Sig3 increase, especially those of Sig1 and Sig3. When DME is blended in the biodiesel, the pressure fluctuations for biodiesel–DME blends are more significant compared with biodiesel. With the increase of DME blended ratio, the mean energy and the standard deviation of Sig1 and Sig3 gradually increase.

Experimental Investigations of Injection and Combustion Parameters of a Homogeneous Charge Compression Ignition (HCCI) Engine with a Multi-Injection Common Rail System

This work experimentally investigates the most imperative parameters that control the injection and combustion processes in a multi-injection HCCI Diesel engine namely; fuel-line pressure, timing of multi-injection events and the resulting in-cylinder pressure. These parameters in addition to the heat release rates are evaluated at different engine loads and speeds over up to 42 successive cycles. The main inter-relations of these parameters are also discussed. Results revealed that the maximum cylinder pressure and temperature in the HCCI engines are lower by 7% compared to similar conventional ones, which could lead to lower NOx emission. In addition, the fuel line pressure exhibits nearly the same major frequency of the waves, 850 to 950 Hz. Those results could be very useful for engine assessment, modeling, control, NOx reduction and power saving.

The effect of diesel fuel-tall oil/ethanol/methanol/isopropyl/n-butanol/fusel oil mixtures on engine performance and exhaust emissions

Tall oil is a waste energy source that can be called as the extract of trees that emerge in paper mills. Fusel oil is a sugar molasses process waste which is a waste alcohol combination of high molecular alcohols. In this study, tall oil acids were mixed with 20% by volume of diesel fuel and alcohol (ethanol, methanol, isopropyl, n-butanol and fusel oil) were added to the same ratio and their effects on combustion, fuel line pressure, engine performance and emissions were investigated. The mixtures were tested by using a single-cylinder engine with compression-ignition, direct injection at constant engine speed (1800 rpm) and 2 Nm, 4 Nm, 6 Nm, 8 Nm engine torques. With the use of fuel mixtures, in-cylinder pressure values decreased in all conditions compared to D100 fuel. The highest drop in in-cylinder pressure values is 7.1% with DT20M20 fuel mixture. Fuel mixtures were found to be sprayed earlier than the injector compared to diesel fuel. BSCF the highest rate of increase was seen with the DT20M20 fuel mixture at 9%. All fuel mixtures have been found to produce reduction in CO and smoke opacity emissions and an increase in HC and NOx emissions. With D100 fuel, emission values measured at (CO) 0.35 ppm and (is) 46%, respectively, decreased to (CO) 0.24 ppm and (is) 33% with the DT20I20 fuel mixture under the same conditions. The highest NOx emission was 14.8% with DT20I20. HC emission using the DT20M20 fuel mixture was determined to be 83 ppm.

RETROFITTING AN EXPERIMENTAL SYSTEM FOR EXAMINING MECHANICAL DIESEL INJECTION SYSTEMS

An experimental rig along with a MATLAB script for examining mechanical diesel injection systems have been successfully developed in this work. The system is capable of extending further to include a high-speed camera for imaging spray breakup events occurring in the near field of injector exit. The system developed in this study allows to record hydraulics characteristics of a number of consecutive injection shots. The MATLAB script allows to isolate fuel line pressure signal of single injection shot from those consecutive events (e.g. 400 shots used in this article), then to output the mean, coefficient of variation (CoV) in fuel line pressure and other interested parameters. The CoV values get a peak of 7% approximately and at the maximum pressure location. The high CoV peak might contribute to the engine cycle-to-cycle variation (CoV of indicated mean of effective pressure - IMEP) and this suggests an investigation to link this with CoV of IMEP in the future in an engine test-bed.

Experimental study on dynamic injection behaviors of biodiesel and its blends in a common-rail injection system

The dynamic injection behaviors of pure biodiesel, high-proportioned biodiesel blends, and low-proportioned biodiesel blends in a common-rail injection system are researched. The effects of biodiesel ratio in the blended fuel and injection condition on the injection rate, cycle injection quantity, and fuel line pressure at the injector inlet are determined. The findings show that the injection duration is extended with the decrease in biodiesel ratio in the blended fuel, and fluctuation amplitude of injection rate in the stable injection stage increases. The first four pressure peaks for pure biodiesel decrease rapidly, while for blends, they decrease slowly, which results in an increasing difference of four pressure peaks between pure biodiesel and blends. With the decrease in biodiesel ratio, the mean volume injection quantity for three fuels gradually increases in the same injection condition. The coefficient of variation of the cycle injection quantity value for biodiesel and its blends with 30 cycles increases. The coefficient of variation value for biodiesel is between 0.4% and 0.7%. Compared with pure biodiesel, the mean volume injection quantity for BD70 increases by about 20–32%, and the coefficient of variation value is between 0.7% and 1.7% for high-proportioned biodiesel blends. The mean volume injection quantity increases by about 36–43% for low-proportioned biodiesel blends and the coefficient of variation value is between 1.1% and 2.1%.

Studying engine cold start characteristics at low temperatures for CNG and HCNG by investigating low-temperature oxidation

Engine cold start characteristics at low ambient temperatures based on first firing cycles were studied on a 1.7-l four-stroke engine for Compressed Natural Gas (CNG) and hydrogen-CNG blend fuels. In these studies engine speed, lambda ((Actual air–fuel ratio)/(Stoichiometric air–fuel ratio)), intake manifold pressure, injection pulse duration, battery voltage, intake manifold temperature, coolant temperature, and fuel line pressure at natural ambient temperature, 0°C, and −7.5°C were measured. Test results indicated for various fuels when ambient temperature decreases, lambda decreases also, but when hydrogen added to CNG (in this investigations the amount of hydrogen was 10% by volume), at similar ambient temperature, lambda increased. This implied that air–fuel mixture became leaner, which in turn could affect unburned hydrocarbons emission. Moreover, when ambient temperature decreases, after-crank-and-fire maximum engine flair speed decreases, but when hydrogen added to CNG, after-crank-and-fire maximum engine flair speed increased in comparison with pure CNG. However, when hydrogen added to CNG some instantaneous rising and falling occurred in engine speed exactly after cranking duration. This research investigated the low-temperature oxidation of CNG and the effect of adding hydrogen at low temperature to find the cause of rising and falling in engine speed. The results indicated consumption of OH by hydrogen during low-temperature oxidation of CNG. The decreased OH concentration leads to retarded heat release and has effect on engine speed.

The emission analysis of an IDI diesel engine fueled with methyl ester of waste frying palm oil and its blends

In this study, the exhaust emissions of an unmodified diesel engine fueled with methyl ester of waste frying palm-oil (biodiesel) and its blends with petroleum based diesel fuel (PBDF) were investigated at the full load-variable speed condition. The relationships between the fuel properties and the air–fuel equivalence ratio, fuel line pressure, start of injection (SOI) timing, and ignition delay were also discussed to explain their effects on the emissions. The obtained test results were compared with the reference values which were determined by using PBDF. The results showed that when biodiesel was used in the test engine, the fuel line pressure increased while air–fuel equivalence ratio and ignition delay decreased. These behaviors affected the combustion phenomena of biodiesel which caused to reduction 57% in carbon monoxide (CO) emission, about 40% in unburned hydrocarbon (HC) emission and about 23% in smoke opacity when compared with PBDF. However, NO x and CO 2 emissions of the biodiesel have showed different behaviors in terms of the engine speed.

Analysis of energy release and NO x emissions of a CI engine fuelled on diesel and DME

Combustion and NO x emissions from a dimethyl ether (DME) fuelled compression ignition engine were investigated. The test engine used consisted of an unmodified two-cylinder direct injection four-stroke air cooled type. The injection timing and injector opening pressure were left unaltered from their diesel fuelling settings. Analysis of the fuel line pressure shows that due to the compressibility of DME the rate of pressure rise was lower, resulting in injection occurring later when compared to diesel injection. The maximum combustion chamber pressure was found to be higher in the case of diesel fuelling. In terms of energy release it was found that with DME this occurs later than in the case of diesel fuelling with the larger proportion occurring just after top dead centre. A comparison of NO x emissions revealed that, at all loads tested, these were higher in the case of DME fuelling and decreased steadily with increasing speed. At the higher speeds however, the levels of NO x monitored were noted to be less than those of their diesel counterpart. Some of the factors influencing the promotion of NO x emissions with DME fuelling are discussed and analysed.

Analysis of the effect of variations in fuel line pressure in high-speed direct injection diesel engines, with high-pressure common rail fuel injection systems on heat release, cylinder pressure, performance, and NOx emissions

This paper is a further development of work previously reported on a wholly analytical approach to heat release modelling and is applicable to high-speed direct injection (HSDI) diesel engines operating with high-pressure common rail fuel injection systems under conditions of predominantly mixing-controlled combustion. The key variable in this treatment is the fuel preparation or combustion rate factor WH which, in conjunction with the primary injection variables, i.e. rail pressure, injection velocity and duration, defines the shape and amplitude of the heat release curve. It was shown in a previous paper that by expressing the fuel preparation rate factor WH as a function of time rather than crank angle, i.e. WHt instead of WHθ, the former can be presented as a nearly linear function of the square of injection velocity, i.e. WHt is directly proportional to the kinetic energy of the injected fuel spray, the latter evidently being the primary influence on the rate of the fuel-air mixing process. The analytical treatment developed in the authors' previous paper then allows heat release rates in the engine, dQ/dθ, to be calculated over a wide range of engine speeds and loads, with the aid of the existing engine simulation code ODES (Otto diesel engine simulation) to predict the associated engine performance and emissions, without resorting to further engine testing.

Some lubrication problems in air-cooled two-cycle engines : J. W. Savin. Lubrication Eng., 18 (1962) 78–82; 5 figs., 3 tables, 5 refs.

Engine cold start characteristics at low ambient temperatures based on first firing cycles were studied on a 1.7-l four-stroke engine for Compressed Natural Gas (CNG) and hydrogen-CNG blend fuels. In these studies engine speed, lambda ((Actual air–fuel ratio)/(Stoichiometric air–fuel ratio)), intake manifold pressure, injection pulse duration, battery voltage, intake manifold temperature, coolant temperature, and fuel line pressure at natural ambient temperature, 0 °C, and −7.5 °C were measured. Test results indicated for various fuels when ambient temperature decreases, lambda decreases also, but when hydrogen added to CNG (in this investigations the amount of hydrogen was 10% by volume), at similar ambient temperature, lambda increased. This implied that air–fuel mixture became leaner, which in turn could affect unburned hydrocarbons emission. Moreover, when ambient temperature decreases, after-crank-and-fire maximum engine flair speed decreases, but when hydrogen added to CNG, after-crank-and-fire maximum engine flair speed increased in comparison with pure CNG. However, when hydrogen added to CNG some instantaneous rising and falling occurred in engine speed exactly after cranking duration. This research investigated the low-temperature oxidation of CNG and the effect of adding hydrogen at low temperature to find the cause of rising and falling in engine speed. The results indicated consumption of OH by hydrogen during low-temperature oxidation of CNG. The decreased OH concentration leads to retarded heat release and has effect on engine speed.

Frictional forces and deformation in axial sliding of a roller.(in German) : L. Pust. Acta Tech. (Prague), 6 (2) (1961) 162–185

Engine cold start characteristics at low ambient temperatures based on first firing cycles were studied on a 1.7-l four-stroke engine for Compressed Natural Gas (CNG) and hydrogen-CNG blend fuels. In these studies engine speed, lambda ((Actual air–fuel ratio)/(Stoichiometric air–fuel ratio)), intake manifold pressure, injection pulse duration, battery voltage, intake manifold temperature, coolant temperature, and fuel line pressure at natural ambient temperature, 0 °C, and −7.5 °C were measured. Test results indicated for various fuels when ambient temperature decreases, lambda decreases also, but when hydrogen added to CNG (in this investigations the amount of hydrogen was 10% by volume), at similar ambient temperature, lambda increased. This implied that air–fuel mixture became leaner, which in turn could affect unburned hydrocarbons emission. Moreover, when ambient temperature decreases, after-crank-and-fire maximum engine flair speed decreases, but when hydrogen added to CNG, after-crank-and-fire maximum engine flair speed increased in comparison with pure CNG. However, when hydrogen added to CNG some instantaneous rising and falling occurred in engine speed exactly after cranking duration. This research investigated the low-temperature oxidation of CNG and the effect of adding hydrogen at low temperature to find the cause of rising and falling in engine speed. The results indicated consumption of OH by hydrogen during low-temperature oxidation of CNG. The decreased OH concentration leads to retarded heat release and has effect on engine speed.