scholarly journals Injection and Combustion Analysis of Pure Rapeseed Oil Methyl Ester (RME) in a Pump-Line-Nozzle Fuel Injection System

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7535
Author(s):  
Flavio Caresana ◽  
Marco Bietresato ◽  
Massimiliano Renzi

This work suggests an interpretation to the quantitatively higher formation of NOx in a compression ignition (CI) engine when fueled with pure biodiesel (B100). A comparative study about the use of rapeseed oil methyl ester (RME) and diesel fuel mixtures on injection timing, in-chamber pressure, heat release rate, and NOx emissions were carried out using a diesel engine equipped with a pump-line-nozzle injection system. Such engines are still widely adopted mainly in agriculture, as the fleet of agricultural machinery is particularly old (often over 20 years) and the use of biofuels can reduce the environmental footprint of the sector. This work aims to supply some general explanations and figures useful to interpret the phenomena occurring within the fuel line and in the combustion process when using biodiesel, as well as in engines with different construction characteristics and fueling systems. Given the contradictory results available in the literature, the so-called “biodiesel NOx effect” cannot be explained solely by the different physical properties of biodiesel (in particular, a higher bulk modulus). Experimental results show that, with the same pump settings, the start of injection with the RME is slightly advanced while the injection pressure values remain almost the same. With the RME, the pressure in the injection line increases faster due to its greater bulk modulus but the pressure rise starts from a lower residual pressure. The start of combustion takes place earlier, the heat release during the premixed phase is steeper, and a higher peak is reached. The NOx emissions with the RME are at least 9% higher when compared to mineral diesel fuel. The greater amount of the RME injected per cycle compensates for its minor lower heating value, and the brake torque at full load is similar to the two analyzed fuels. Finally, a variation of the pump line timing is evaluated in order to assess the effect of the delay and the advance of the injection on the performance of the engine and on the emissions. A viable and simple solution in the variation of the injection strategy is suggested to counterbalance the biodiesel NOx effect.

Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.


2008 ◽  
Vol 12 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Kapilan Nadar ◽  
Pratap Reddy ◽  
Rao Anjuri

In this work, an experimental work was carried out to compare the performance of biodiesels made from non edible mahua oil and edible gingili oil in dual fuel engine. A single cylinder diesel engine was modified to work in dual fuel mode and liquefied petroleum gas was used as primary fuel. Biodiesel was prepared by transesterification process and mahua oil methyl ester (MOME) and gingili oil methyl ester (GOME) were used as pilot fuels. The viscosity of MOME is slightly higher than GOME. The dual fuel engine runs smoothly with MOME and GOME. The test results show that the performance of the MOME is close to GOME, at the pilot fuel quantity of 0.45 kg/h and at the advanced injection timing of 30 deg bTDC. Also it is observed that the smoke, carbon monoxide and unburnt hydro carbon emissions of GOME lower than the MOME. But the GOME results in slightly higher NOx emissions. From the experimental results it is concluded that the biodiesel made from mahua oil can be used as a substitute for diesel in dual fuel engine.


Biofuels derived from vegetable oils are known to be promising alternative fuels for diesel engines. The possibility of using mixtures of petroleum diesel fuel with rapeseed oil and rapeseed oil methyl ester as environmentally friendly motor fuels is considered. The practicability of changing the composition of these mixtures in accordance with the engine operating mode is shown. A technique for multicriteria optimization of the composition of such mixed biofuels is suggested. The basic characteristics of the optimal composition of these mixed biofuels are calculated. A device for regulating fuel’s composition is proposed. The basic characteristic of regulation of the blended biofuel composition realized by the device is presented. Keywords diesel engine; combustion chamber; oil diesel fuel; rapeseed oil; rapeseed oil methyl ester; biofuel mixture; ecological characteristics; exhaust gases toxicity


Author(s):  
K Anand ◽  
R P Sharma ◽  
P S Mehta

Suitability of vegetable oil as an alternative to diesel fuel in compression ignition engines has become attractive, and research in this area has gained momentum because of concerns on energy security, high oil prices, and increased emphasis on clean environment. The experimental work reported here has been carried out on a turbocharged direct-injection multicylinder truck diesel engine using diesel fuel and jatropha methyl ester (JME)-diesel blends. The results of the experimental investigation indicate that an increase in JME quantity in the blend slightly advances the dynamic fuel injection timing and lowers the ignition delay compared with the diesel fuel. A maximum rise in peak pressure limited to 6.5 per cent is observed for fuel blends up to 40 per cent JME for part-load (up to about 50 per cent load) operations. However, for a higher-JME blend, the peak pressures decrease at higher loads remained within 4.5 per cent. With increasing proportion of JME in the blend, the peak pressure occurrence slightly advances and the maximum rate of pressure rise, combustion duration, and exhaust gas temperature decrease by 9 per cent, 15 per cent and 17 per cent respectively. Although the changes in brake thermal efficiencies for 20 per cent and 40 per cent JME blends compared with diesel fuel remain insignificant, the 60 per cent JME blend showed about 2.7 per cent improvement in the brake thermal efficiency. In general, it is observed that the overall performance and combustion characteristics of the engine do not alter significantly for 20 per cent and 40 per cent JME blends but show an improvement over diesel performance when fuelled with 60 per cent JME blend.


Author(s):  
Seppo A. Niemi ◽  
Juha M. Tyrva¨inen ◽  
Mika J. Laure´n ◽  
Va¨ino¨ O. K. Laiho

In the near future, crude oil based fuels must little by little be replaced by biofuels both in the region of the European Union (EU) and in the United States. Bearing this in mind, a Finnish-made off-road diesel engine was tested with a biofuel-diesel fuel blend in the Internal Combustion Engine (ICE) Laboratory of Turku Polytechnic, Finland. The biofuel was cold-pressed mustard seed oil (MSO). The engine operation, performance and exhaust emissions were investigated using a blend of 30 mass-% MSO and 70 mass-% diesel fuel oil (DFO). The injection timing of the engine was retarded considerably in order to reduce NOx emissions drastically. The main target was then to find out, whether the blended oxygen containing MSO would speed up the combustion so that the particulate matter (PM) emissions would remain unchanged or even decrease despite the injection retardation. As secondary tasks of the study, the NOx readings of the CLD and FTIR analyzers were compared, and exhaust contents of unregulated compounds were determined. Retarding the injection timing resulted in a significant decrease of NOx emissions, but in an increase in smoke, as expected. At retarded timing, the NOx emissions remained almost unchanged, but the amount of smoke decreased when the engine was run with the fuel blend instead of DFO. At retarded timing at rated speed, the number of ultra-fine particles decreased, but the amount of large particles increased with DFO at full load. At 10% load, however, the particle number increased in the entire particle size range due to retardation. At both loads, the use of the fuel blend slightly reduced larger particles, whereas the number of small particles somewhat increased. At full load at an intermediate speed of 1500 rpm, the PM results were very similar to those obtained at rated speed. At 10% load with DFO, however, the injection retardation led to a higher number of larger particles, the smaller particles being at almost an unchanged level. With the fuel blend, the particle number was now higher within almost the whole particle diameter range than with DFO. Considerably higher NO2 contents were usually detected with FTIR than with CLD. The shape of the NOx result curves were rather similar independent of which one of the analyzers was used for measurements. The NOx contents were, however, generally some ten ppms higher with FTIR. The exhaust contents of unregulated compounds were usually low.


Author(s):  
Eduardo Barrientos ◽  
Ivan Bortel ◽  
Michal Takats ◽  
Jiri Vavra

Engine induced swirl improves mixing of fuel and air and at optimal values accelerates burn, improves the combustion stability and can decrease particulate matter (PM). However, swirl increases convective heat loss and cylinder charge loss and could increase nitrogen oxides (NOx) emissions. High intensity of swirl could impede flame development and increases emissions of total hydrocarbons (THC) and carbon monoxide (CO). Therefore, careful and smart selection of optimal swirl values is paramount in order to obtain beneficial impact on combustion and emissions performance. This study is conducted on a 0.5L single cylinder research engine with common rail (CR) diesel injection system, with parameters corresponding to modern engines of passenger cars. The engine has three separate ports in the cylinder head. The change of swirl ratio is defined by closing appropriate ports. There are three levels of swirl ratio under study — 1.7, 2.9 and 4.5, corresponding to low, medium and high swirl levels respectively. This study highlights the influence of intake induced swirl on combustion parameters and emissions. Assessed combustion parameters are, among others, heat release rate, cylinder pressure rise and indicated mean effective pressure. Assessed emissions are standard gaseous emissions and smoke, with emphasis on PM emissions. An engine speed of 1500 rpm was selected, which well represents common driving conditions of this engine size. Various common rail pressures are used at ambient inlet manifold pressure (without boost pressure) and at 1 bar boosted pressure mode. It is found that when the swirl level is increased, the faster heat release during the premixed combustion and during early diffusion-controlled combustion causes a quick increase in both in-cylinder pressure and temperature, thus promoting the formation of NOx. However, since swirl enhances mixing and potentially produces a leaning effect, PM formation is reduced in general. However, maximum peak temperature is lower for high swirl ratio and boosted modes due to the increase of heat transfer into cylinder walls. Furthermore, it is necessary to find optimal values of common rail pressures and swirl ratio. Too much mixing allows increase on PM, THC and CO emissions without decrease on NOx emissions in general. Common rail injection system provides enough energy to achieve good mixing during all the injection time in the cases of supercharged modes and high common rail pressure modes. Positive influence of swirl ratio is found at lower boost pressures, lower revolution levels and at lower engine loads. The results obtained here help providing a better understanding on the swirl effects on diesel engine combustion and exhaust emissions over a range of engine operating conditions, with the ultimate goal of finding optimal values of swirl operation.


2020 ◽  
Vol 181 (2) ◽  
pp. 11-18
Author(s):  
Mariusz CHWIST ◽  
Michał GRUCA ◽  
Michał PYRC ◽  
Magdalena SZWAJA

The article presents results of investigation on the combustion of a mixture of oil from pyrolysis of tires and basic fuel in an internal combustion reciprocating piston engine. The tested fuel consisted of: diesel oil and oil from pyrolysis of tires at amount of 10% by volume. The tests were carried out on a single-cylinder naturally aspirated compression-ignition engine. The engine is equipped with a common rail fuel injection system and an electronic control unit that allows changing injection timing. A comparative analysis of pressure-volume charts for the reference fuel, which was diesel, and for a mixture of diesel with the addition of 10% oil from tire pyrolysis was carried out during the study. Injector characteristics for the reference fuel and the mixture were determined. Engine efficiency for both fuels was determined. Unrepeatability of the engine work cycles for the diesel fuel and the tested mixture was calculated. Finally, the share of toxic exhaust components in exhaust gases was analyzed. It was found that pyrolisys oil from tires can be used as additive to regular diesel fuel at amount up to 10%, however, toxic exhaust gases emission was increased.


Sign in / Sign up

Export Citation Format

Share Document