Delay Of Injection Timing Research Articles

Effects of Injection Timing and Antioxidant on NOx Reduction of CI Engine Fueled with Algae Biodiesel Blend Using Machine Learning Techniques

Fossil fuels are depended upon often in the transport sector. The use of diesel engines in all areas produce pollutants, such as NOx and CO, which cause serious environmental pollution and hazards, such as global climate change and breathing difficulties. Conventional fuel usage should be reduced, and there should be a shift toward alternative fuels. For compression ignition (CI) engines, microalgae biodiesel has been promoted as a clean, sustainable fuel. This is because it possesses desired traits, such as a quick rate of development, high productivity, and the capacity to turn CO2 into fuel. When algal biodiesel is used, pollutants, such as CO, UBHC, and smoke, are typically reduced, whereas NOx emissions are typically increased. The adoption of an exhaust gas recirculation technology and the advancement or delay of injection timing can effectively reduce NOx formation. Incorporating antioxidant chemicals such as butylated hydroxyl anisole (BHA) into fuel also minimizes NOx formation. In this study, the use of microalgae biodiesel as a substitute fuel for CI engines was investigated by altering the injection timing and adding each antioxidant in two doses. According to ASTM standard test procedures for biodiesel, the fuel qualities of various blends of algal biodiesel with antioxidants were tested and compared with the diesel fuel. The experiments were conducted using CI engines, and parameters were examined, such UBHC, CO, NOx, and smoke opacity. In comparison to diesel fuel, B20 + 30% BHA (21 bTDC) blends produced 49% lower oxides of nitrogen. The smoke, HC, and CO emissions of fuel blend B20 + 30% BHA (25 bTDC) were reduced by 33.33%, 32.37%, and 11.21%, respectively, compared with those of diesel fuel. The fuel blend B20 + 30% BHA (25 bTDC) showed the highest brake thermal efficiency of 14.52% at peak load condition. A multi-output regression deep long short-term memory (MDLSTM) model was designed to predict the performance and emissions of CI engines operating with varied fuel mixtures. The average RMSE and R2 values for the proposed MDLSTM were 0.38 and 0.9579, respectively.

Experimental investigation on combustion characteristics and influencing factors of PODE/methanol dual-fuel engine

PODE/methanol dual-fuel combustion mode was conducted on a four-cylinder common-rail engine with PODE direct injection and methanol intake fumigation. This study is aimed to investigate the effects of methanol substitution ratio (MSR), injection timing and inlet temperature on in-cylinder combustion, emission characteristics and fuel economy of dual-fuel engine. Results show that with the increase of MSR, the ignition delay of dual-fuel engine is prolonged, and the COV increases. At medium and small loads, the peak combustion pressure decreases, and the combustion phase is delayed. At high load, the peak values of heat release rate and combustion pressure increase, combustion duration is shortened, and slight knock occurs at 40% MSR. Dual-fuel mode has benefits in reduction of NOx and soot, while increases NO2 and HCHO emissions. With the delay of injection timing, combustion duration is first prolonged and then shortened. The excessive delay of injection timing leads to increased fluctuation of combustion pressure, and partial misfire occurs. With the increase of inlet temperature, the peak values of heat release rate and combustion pressure increase significantly, combustion duration is shortened, and the COV increases. At the inlet temperature of 65 °C, methanol spontaneous combustion occurs near TDC, and thermal efficiency increases to 44.6%.

Experimental Investigation of Combustion Characteristics on Opposed Piston Two-Stroke Gasoline Direct Injection Engine

The combustion characteristics of an opposed-piston two-stroke gasoline engine are investigated with experiment. The energy conversion and exergy destruction are analyzed and the organization method of the combustion process is summarized. The effects of phase difference, scavenging pressure, injection timing, ignition timing, and dual spark plug ignition scheme on the combustion process and engine performance are discussed, respectively. The heat release rate of the opposed-piston two-stroke gasoline engine is consistent with the conventional gasoline engine. With the increase of opposed-piston motion phase difference, the scavenging efficiency decreases and overmuch residual exhaust gas is not beneficial to the combustion process. Meanwhile, the faster relative velocity of the opposed-piston near the inner dead center enhances the cylinder working volume change rate, which leads to the rapid decline of in-cylinder pressure and temperature. The 15 °CA of opposed-piston motion phase difference improves the scavenging and combustion process effectively. When scavenging pressure is 0.12 MPa, the scavenging efficiency and heat release rate are improved at medium-high speed conditions. With the delay of injection timing, the flame developing period decreases gradually, and the rapid burning period decreases and then increases. The rapid burning period may reach the minimum value when the injection advance angle is 100 °CA. With the delay of ignition timing, the flame developing period increases gradually, and the rapid combustion period decreases and then increases. The rapid combustion period may reach the minimum value when the ignition advance angle is 20 °CA. Notably, the flat-top piston structure should be matched with the dual spark plug, which the ignition advance angle is 20 °CA at medium-high load conditions.

Influence of injection parameters on combustion, gaseous emissions and particle size distribution of a CRDI diesel engine operating with PODE/diesel blends

This study deals with the experimental research on combustion process, gaseous emissions characteristics and particle size distributions of a high pressure common-rail direct injection (CRDI) diesel engine operating with PODE/diesel blends at different injection pressures (80 MPa, 90 MPa and 100 MPa) and injection timings (0.5°CA ATDC, 2.5°CA ATDC and 4.5°CA ATDC). The testing fuels were neat diesel, PODE/diesel blends with PODE volume fractions of 10% and 20%, which were marked as P0, P10 and P20 respectively. The results show that the maximum combustion pressure and peak value of heat release rate increase with the increment of injection pressure while the combustion pressure decreases slightly with the delay of injection timing. The CO, HC and soot emissions of the blended fuels decrease obviously with the increase of injection pressure, while the NOx increases, in which the increasing extent of NOx by fueling P10 is smaller than those of P0 and P20 fuels. Even though CO, HC and soot of the three fuels increase with the delay of injection timing, the NOx emissions decrease and the gaseous emissions of P10 fuel are still less affected by injection timing. The peak values of particle number concentration curves of the blends decrease with higher injection pressure, among which the proportion of accumulation particles decreases and the proportion of nucleation particles increases. The particle number concentration increases with the delay of injection timing for each testing fuel, but the geometric mean diameter (GMD) of P10 particles is little affected by the injection timing. Also, the particle diameter corresponding to the peak concentration for each testing fuel decreases with the increase of injection pressure and the advance of injection timing.

Effects of the injection timing on knock and combustion characteristics in dual-fuel dual-injection engines

To utilize ethanol fuel in spark ignition engines more efficiently and flexibly, a new ethanol/gasoline dual-direct injection concept in gasoline engine is proposed. Therefore, based on the dual-fuel dual-direct injection system, the effects of different injection timings and two injector positions on the characteristics of combustion were studied comprehensively, and the effects of different octane numbers and temperature stratifications on knock and combustion were explored. The results show that as for Position A (ethanol injecting toward spark plug), with the delay of injection timing, knock tendency and its intensity increase initially and then decrease due to the comprehensive effect of ethanol evaporation and fuel stratification; on the contrary, for Position B (ethanol injecting toward end-gas region), retarding the injection timing of ethanol can effectively reduce the knock propensity. As for the engine performance, a dual-direct injection performs best, especially the retarded injection timing of ethanol for Position A. It can be found that with the delay of the fuel injection timing, the torque first increases and then decreases. The brake-specific fuel consumption decreases initially and then increases at maximum brake torque spark timing.

Effect of EGR and Fuel Injection Strategies on the Heavy-Duty Diesel Engine Emission Performance under Transient Operation

To reduce the smoke and nitrogen oxide (NOx) emissions; a detailed study concerned with exhaust gas recirculation (EGR) and diesel injection strategy was conducted on a two-stage series turbocharging diesel engine under transient operating condition. One transient process based on the constant speed of 1650 r/min and load increases linearly from 10% to 100% within 5 s was tested in this study. The effect of the EGR valve control strategy on engine transient performance was examined. The results show that better air-fuel mixing quality can be obtained with the optimized the EGR valve open loop control strategy and the smoke opacity peak decreased more than 64%. Under the EGR valve close loop control strategy; the smoke opacity peak was lower than with open loop control strategy; but higher than without EGR. The effect of fuel injection strategy on engine transient performance was examined with the EGR valve close loop control. The results show that sectional-stage rail pressure (SSRP) strategy (increasing injection pressure from a turning point load to 100% load) and optimizing fuel injection timing can improve the engine emission performance. The satisfactory results can be obtained with lower NOx (382 ppm) emissions and the smoke opacity peak (3.8%), when the turning point load is set to 60% with the injection timing delay 6° CA.

Assessment on the consequences of injection strategies on combustion process and particle size distributions in Euro VI medium-duty diesel engine

Although there are already several works where the influence of injection parameters on exhaust emissions, and specifically on particulate matter emissions, in diesel engines has been evaluated, the diversity in the results that can be found in the literature indicates the need to carry out new experiments that can provide more information about the influence of these parameters on modern diesel engines. This study intends to be placed within this scientific framework, hence a parametric study was carried out based on the independent modification of the main injection timing and the injection pressure with respect to the nominal conditions of a new Euro VI direct injection diesel engine. Four steady-state operation points of the engine map were chosen: 25% load and 950 r/min, 50% load and 1500 r/min, 75% load and 2000 r/min and 100% load and 2200 r/min, where in each of these operation points, the variations of the injection parameters in the study on the combustion process and its consequent impact on the particle size distribution, including an analysis of the geometric mean diameter values, were evaluated. The results showed that the different injection strategies adopted, despite not significantly affecting the engine efficiency, did cause a significant impact on particle number emissions. At the low load operation, the size distribution showed a bimodal structure, and as the main injection timing was delayed and the injection pressure was decreased, the nucleation-mode particle concentration decreased, while the accumulation-mode particle concentration increased. In addition, at medium load, the nucleation-mode particle emission decreased considerably while the accumulation-mode particle emission increased, and this increase was much greater with the main injection timing delay and the injection pressure reduction. Similar behavior was observed at high load, but with a much more prominent pattern.

Experimental studies on the combustion and particulate matter emission characteristics of biodiesel surrogate component/diesel

By blending methyl decanoate (MD) and methyl hexanoate (MH) with diesel, the combustion and particulate matter (PM) emission characteristics were investigated. The experiments were carried out at various direct injection timings (−1/−3/−5/−7/−9/−11/−13 °CA ATDC) and EGR rates (0/20%/40%/60%) along with a fuel consumption fixed on 45 mg/cycle. The results showed that with the delay of injection timing and the increase of EGR rate, the in-cylinder maximum pressure decreased and the peak value of heat release rate increased. By retarding the direct injection timing, the particle geometric mean diameter (GMD) of diesel, MD/diesel and MH/diesel could be reduced by 18.4%, 68.6% and 68.1%, respectively. At the late injection timing, the total particle number of MD/diesel and MH/diesel increased sharply from about 4 × 106#/cm3 to around 1 × 108#/cm3, while the diesel total particle number decreased remarkably from 1.1 × 108#/cm3 to 4.2 × 107#/cm3. Postponing the injection timing and increasing the EGR rate could reduce the number concentration and GMD of accumulation mode particles. MH/diesel possessed a lower particle number concentration as a result of the higher oxygen content, better volatility and longer ignition delay. The total particle GMD and nucleation mode particle GMD of two blends were larger than those of diesel, while the accumulation mode particle GMD was less than that of diesel. The presence of oxygen in fatty acid methyl ester (FAME) molecule was effective on prohibiting the formation and development of accumulation mode particles, while not having significant effects on the nucleation mode particles. At the injection timing of −7 °CA ATDC, diesel, MD/diesel and MH/diesel got the maximum indicated thermal efficiency of 44.1%, 43.3% and 43.3%, respectively.

An experimental study of emission and combustion characteristics of marine diesel engine with fuel pump malfunctions

Presented paper shows the results of the laboratory study on the relation between the chosen malfunctions of a fuel pump and the exhaust gas composition of the marine engine. The object of research is a laboratory four-stroke diesel engine, operated at a constant speed. During the research over 50 parameters were measured with technical condition of the engine recognized as “working properly” and with simulated fuel pump malfunctions. Considered malfunctions are: fuel injection timing delay and two sets of fuel leakages in the fuel pump of one engine cylinder. The results of laboratory research confirm that fuel injection timing delay and fuel leakage in the fuel pump cause relatively small changes in thermodynamic parameters of the engine. Changes of absolute values are so small they may be omitted by marine engines operators. The measuring of the exhaust gas composition shows markedly affection with simulated malfunctions of the fuel pump. Engine operation with delayed fuel injection timing in one cylinder indicates CO2 emission increase and NOx emission decreases. CO emission increases only at high the engine loads. Fuel leakage in the fuel pump causes changes in CO emission, the increase of CO2 emission and the decrease of NOx emission.

Simulation Research of Natural Gas Injection Timing on Combustion Process in a Diesel Engine Fueled with Pilot-Ignited Directly-Injected Natural Gas

The numerical model of diesel engine fueled with pilot-ignited directly-injected natural gas is built, and the influence of natural gas injection timing on the combustion process is studied using CFD software. And obtained the following conclusions, as the delay of natural gas injection timing, the maximum of the mean pressure and mean temperature decrease gradually and the timings for the maximum value increase. With every delay of 5 °CA of the injection, the mean pressure reduces by about 16%.As the delay of injection timing, the delay of the timing of the high temperature and the range decrease for the high temperature region, and this is beneficial for the emission of NO, but not conducive to the emission of HC、CO and PM

Influence of Fuel Injection on Gasoline Engine Performance

Because of the most common method of preparing the fuel-air mixture for gasoline-fueled engines is port fuel injection (PFI). For reducing the wall-film entering the cylinder in liquid phase, the phenomena of wall-film entering the cylinder in liquid phase should be at minimum lever or be avoided. So the first thing for learning the wall-film is to detect the way of the wall-film entering the cylinder. Therefore, the way of the wall-film enter the cylinder in liquid phase is detected by changing the temperature of the wall-film location and time for wall-film evaporated. Then the way is validated by experiment test bed and it is improved that the way is feasible. At the end the influence of injection timing and fuel ratio on engine performance is studied based on the test bed.The results show that regardless of the expansion stroke or the intake stroke fuel injection the injection timing delay will decrese the engine power and make emission deterioration meanwhile the twice fuel injection can improve the fuel film evaporation resulting of high-speed airflow of intake charge. DOI: http://dx.doi.org/10.11591/telkomnika.v11i4.2398

Effects of Fuel Injection Timing on Combustion and Emissions of a Spark-Ignition Methanol and Methanol/Liquefied Petroleum Gas (LPG) Engine during Cold Start

The combustion and emission characteristics of spark-ignition (SI) methanol and methanol/ liquefied petroleum gas (LPG) engines under different fuel injection timings during cold start have been studied by means of a cycle-by-cycle control strategy. The results showed that the methanol injection timing, the LPG injection timing, and the LPG injection timing delay relative to the methanol injection timing affect cold-start combustion characteristics and emissions of hydrocarbons, formaldehyde, and unburned methanol significantly. The methanol injection timing, the LPG injection timing, and the LPG injection timing delay relative to the methanol injection timing can be optimized to ensure that most fuels enter into the cylinder in the injection cycle and the following cycle and that reliable ignition and combustion happen in the third cycle. Optimal control of the fuel injection timing and the LPG injection timing delay relative to the methanol injection timing improves firing performances, reduces the hydr...

NOx Emissions From a Diesel Engine Fueled With Natural Gas

The performance and emission characteristics of a single-cylinder two-stroke diesel engine fueled with direct injection of natural gas entrained with pilot diesel ignition enhancer have been measured. The thermal efficiency of the optimum gas-diesel operation was shown to exceed that of the conventional diesel at full load, but to be less at part load where the ignition delay was excessive. At high load, where the NOx emission problem is most serious, substantial reduction in NOx emission rate was obtained with delay of injection timing and also with use of exhaust gas recirculation. Measured cylinder pressures were used with a three-zone combustion model to determine ignition delay and the temperatures of the burned gas. The predicted NOx emissions based on equilibrium concentration of NO at the maximum burned gas temperature were found to correlate closely with exhaust pipe measurements of NOx.