Diesel Engine Bench Research Articles

Comparative assessment of emissions, performance, and economics parameters for a dual–fuel diesel generator operating with rice bran biodiesel and hydrogen

The first step to achieving an energy transition is partially substituting fossil fuels with other more environmentally friendly alternatives, such as hydrogen gas. The current research aims to evaluate the influence of hydrogen in a diesel generator fueled with rice bran biodiesel. The above encourages the use of hydrogen and biodiesel production from residual raw material. For the development of the research, a diesel engine bench was used, which operated in five load conditions: 20 %, 40 %, 60 %, 80 %, and 100 %, and was fed with three fuels: −100 %, RB-10 %, and RB-10 % + H2(30 %). The results show that the mixture RB-10 % + H2(30 %) causes a 3.14 % reduction in BSFC and a 3.26 % increase in energy conversion efficiency. In addition, it is observed that a 9.90 %, 12.57 %, and 10.99 % decrease in HC, CO, and smoke opacity emissions compared to pure diesel. On the other hand, the mixture RB-10 % + H2(30 %) reduces by 4.44 %, 5.07 %, and 7.06 % the environmental, social, and ecological impact due to CO2, HC, and CO emissions, as well as a 3.93 % reduction in engine operating cost compared to RB-10 % biodiesel. In general, hydrogen injection is a promising alternative to promote the use of rice bran biodiesel due to its increased performance characteristics and reduced pollutant emissions without the need to modify the engine.

Promoted catalytic property of Cu/SSZ-13 by introducing a minority of Mn for NO removal from diesel engine exhaust

The Cu-exchanged SSZ-13 with the small-pore chabazite framework is considered as a highly efficient catalyst for selective catalytic reduction of NO with NH3 (NH3-SCR). In order to further improve the catalytic property, a series of Mn ion-assisted Cu/SSZ-13 powder catalysts were prepared by co-exchange method and stepwise exchange method. It is found that the NH3-SCR activity, N2 selectivity, hydrothermal stability and sulfur resistance of Cu/SSZ-13 are promoted by introducing a minority of Mn (0.15%–0.23%(mass)) through co-exchange method. Characterization results revel that the Cu,Mn co-exchange enables the higher amounts of Cu2+ active sites, the abundant medium strong and strong acid, the optimized ratio of lewis acid to Brønsted acid, etc., which are required for a good NH3-SCR catalytic property over broad temperature range and under harsh working environment. Moreover, a monolithic catalyst was prepared by impregnating a cordierite ceramic support into the coating slurry containing the optimized CuMn/SSZ-13 powder. The diesel engine bench tests show that Cu,Mn co-exchange gives the monolith catalyst a better catalytic property than commercial catalysts. This work provides an important guidance for the rational design of secondary-ion-assisted zeolites applied in NH3-SCR.

Detection of gaseous pollutants emitted from engine powered by biodiesel and diesel mixtures

Nowadays air pollution has been regarded as a serious environmental problem. One of the main generators of air pollution is the transportation, since the gas combustion from various chemical species is emitted mainly in urban transportation, using mainly diesel fuel. The use of renewable fuels is an attractive alternative choice to reduce environmental impacts. Brazil stands out in the current world scene as a major of alternative energy producer. Brazilian government introduced a program that includes blends of biodiesel to diesel in order to reduce the environmental impact caused by air pollution. Therefore, this study aims to evaluate the emission of gaseous pollutants using a diesel engine bench with mixtures of B5, B10, B15, B20, B25 and B50 of biodiesel in diesel. For this type of analysis, the Infrared Analyser was used to detect CO2 in the range of 1.88 to 2.76 %, electrochemical sensors were used to detect CO in the range of 1161 to 1485 ppmv and NOx in the range of 213 to 351 ppmv.

The effect of various urea-in-water solution types on exhaust particle number emission.

In order to qualitatively evaluate the impact of urea-in-water solution on the particle number emission, five different urea types were chosen under diesel engine bench test. The results show that compared to the instantaneous particle concentrations without injection, the instantaneous particle concentrations with injection increase distinctly, which are larger around 0.3-1.2 times than that without urea-in-water solution. At high speed phase, the instantaneous particle concentrations with urea-in-water solution injection rise obviously, especially for C and E solutions. In addition, the particle size distribution characteristic does not change with the urea-in-water solution dosing. The PN emission factors follow the sequence of C solution > E solution > A solution > B solution > D solution. It is deduced that the metallic element contents in the urea-in-water solution play a key role for the PN emission factor. In the future, the particle formation due to urea-in-water solution injection should be given more attention.

Determination of policyclic aromatic compounds, (PAH, nitro-PAH and oxy-PAH) in soot collected from a diesel engine operating with different fuels

A qualitative and quantitative analysis of polycyclic aromatic compounds (PACs; polycyclic aromatic hydrocarbons (PAHs), oxygenated and nitrated polycyclic aromatic hydrocarbons (OPAHs and NPAHs)) present in the soluble organic fraction (SOF) of different soot samples has been carried out to determine the effect of soot-generation conditions on their composition and health effects. The soot samples were generated using a diesel engine bench powered by diesel (DS) and biodiesel (BS) fuels under different combustion conditions. To optimize the procedure, a surrogate soot (Printex-U) and a certified reference material (SRM1650b) were also tested. Different extraction methods were used to extract the PAHs, OPAHs and NPAHs, and the Soxhlet technique using pyridine:acetic acid 1 % was found to be the most suitable procedure to extract the highest concentration (ng mg−1) and more types of PAHs and OPAHs from the soot. The results show that the PACs identified, and their concentrations, depend on the formation and collection conditions. The predominant compounds in all soot samples studied were fluorene (Flo), phenanthrene (Phe), fluoranthene (Fla), pyrene (Pyr), 9-fluorenone (9Flo) and 9,10-anthraquinone (9,10Anq). As such, the presence of these PACs in the atmosphere of urban and rural areas can mainly be attributed to the emissions from diesel vehicles. The percentage of OPAHs with respect to total PACs was highest in the soot generated from a biofuel. These oxidized compounds favor regeneration of the diesel particulate filter (DPF). The results also indicate that the carcinogenicity of the soot depends on the combustion conditions and type of fuel.

Comprehensive Experimental and Numerical Optimization of Diesel Engine Thermal Management Strategy for Emission Clarification and Carbon Dioxide Control

Improving the thermal efficiency of truck diesel engines requires comprehensive optimization of the engine, exhaust aftertreatment (EAT), and possible waste heat recovery (WHR). Lower exhaust temperature at mid and low working points has caused difficulty in both emission clarification and heat recovery, which requires thermal management. Based on the diesel engine bench test and separate bench tests, this paper focuses on the thermal management strategy optimization, to increase the exhaust temperature at lower working points and optimize the thermal efficiency of the whole system. The test and numerical analysis showed that as exhaust temperature increased from 200~250 °C to 300~350 °C, soot passive regeneration reactions were enhanced, nitrogen oxide emission decreased, and energy recovery was improved. Moderate throttle valve adjustment coupled with early post injection could effectively achieve the required temperature increase. The optimized thermal management strategy increased the fuel consumption rate by no more than 1%. Meanwhile, the WHR system output increased significantly, by 62.55% at a certain mid–low working point. System CO2 emission decreased by an average of 5.4% at selected working points.

Study on removing marine multiple pollutants in raw exhaust gas with a novel composited method combined with pre-agglomeration and wet scrubbing technology.

Most of the existing oxidation denitrification methods need longer residence time to obtain higher NOx removal efficiency. In this study, urea peroxide (CO(NH2)2·H2O2) was first used for removing SO2 and NOx on diesel engine bench. The addition of ferrous sulfate can enhance the oxidant capacity of the solution. The better removal efficiency and lower nitrate content in liquid can be achieved in short exhaust gas residence time. The raw gas flow and residence time contained the actual application situation in ships and have high reference value. The removal efficiency decreased with the increase of gas flow, and the reaction temperature, urea peroxide concentration, liquid-gas ratio were the main factors. The optimal Fe2+ concentration of 50mmol/L and pH value of 4 were determined. The urea peroxide concentration, reaction temperature, and liquid-gas ratio were 9%, 70℃, and 10L/m3 respectively. The maximum gas treatment capacity was about 100L/min, and residence time was close to 10s for the scrubber. The pre-agglomerating method were used to improve the particle capturing efficiency combined with spray technology. The composited method can realize the synchronous and efficient removal of multiple pollutants in a single scrubber. The possibility of application on ship was further increased.

Development and Validation of a Vibration-Based Virtual Sensor for Real-Time Monitoring NOx Emissions of a Diesel Engine

With a strong legal basis and regulatory authority, cost-effective transient emission sensors that reflect real-driving emissions are key factors for accomplishing environmental requirements. It is difficult for the existing NOx emission monitoring techniques to achieve a balance between accuracy and timeliness. Fundamentally, in-cylinder combustion is the thermodynamic cause of NOx emissions and the main excitation source for engine vibration and noise emissions. A novel vibration-based virtual NOx sensor is developed based on these critical relationships for real-time NOx monitoring. First, the correlation between vibration and NOx emission was characterized in-depth. Then, a technique of constructing two-dimensional filters for vibration signals is proposed to extract combustion-related information. A principal component regression (PCR) model for NOx prediction was established based on the reconstructed in-cylinder pressure. Finally, the virtual NOx sensor is tested and validated on a single-cylinder diesel engine bench. The virtual NOx sensor is proven to meet the accuracy requirement of vehicle emission monitoring for both steady-state and transient conditions and has a better frequency response compared to the emission measurement system.

Numerical and Experimental Research on Thermal Insulation Performance of Marine Diesel Engine Piston Based on YSZ Thermal Barrier Coating

Although YSZ ceramic coating has been used in the field of aeroengines for a long time to protect blades from high temperature erosion, its application on marine engines is still very rare. In this study, YSZ powder was sprayed onto the upper surface of the Al-Si alloy piston by atmospheric plasma spraying. The piston with or without ceramic coatings was applied to the diesel engine bench, and the ship propulsion characteristics test was carried out to study the effect of the coating on the performance of the diesel engine when the ship was sailing. The temperature field results show that under 25% load, the temperature of the top surface of the coated piston is about 30.91 °C higher than that of the conventional piston. The increase in the temperature of the combustion chamber is conducive to better combustion of the fuel in the cylinder of the diesel engine. Therefore, when the marine diesel engine is tested for propulsion characteristics, the thermal efficiency is increased by 5% under the condition of 25% load.

Bench experimental research of cylinder oil on large marine diesel engines

To lower the risks of the real ship test of the cylinder oil of large marine low-speed two-stroke marine diesel engine, A 6S50ME marine diesel engine was selected to do bench test about cylinder oil. In the calibration condition, the test cylinder oil and the reference cylinder oil were compared. The test results show that the wear amount of cylinder liners, piston rings and piston-ring-grooves is consistent with the wear condition judged by the metal element content detected by the residual oil of the cylinder. At the same time, combined with the evaluation result of the detergency and dispersibility of the cylinder oil, it can effectively judge whether the oil product can be tested on the ship. Since wear volume of element Cr and Fe tends to the stabilization after 60 hours, so it is feasible to set the diesel engine bench test at 100 hours. In addition, special attention should be paid to the control of water outlet temperature and exhaust gas temperature in the test. The cylinder oil evaluated in the above way meets the requirements of OEM after the actual ship test. Thus, the assessment method of cylinder oil based on the bench test is feasible, and can greatly shorten the test time and reduce the test cost.

Effect of Lubricant Additives on the Oxidation Characteristics of Diesel Engine Particulate Matter

Three common lubricant additives, including an antioxidant, detergent, and an antifoamer, were added to diesel fuel to perform a diesel engine bench test. Particulate matter samples underwent thermogravimetric analysis to investigate the effect of lubricant additives on the particulate matter oxidation process, characteristic temperature, and activation energy. The results showed the following. Different lubricant additives result in different variation trends in the thermogravimetric curve of a particulate matter sample by varying the rotating speed and torque. When the rotating speed was stable, as the torque increased, the ignition temperature of the particulate matter of Fuel C declined rapidly during the initial stage and then increased rapidly. When the torque was stable, as the rotating speed increased, the ignition temperature of the particulate matter of Fuel C increased initially and then declined. The particulate matter of Fuel C had the lowest level of activation energy at approximately 57.89 J·mol−1. The particulate matter of Fuel A had the highest level of activation energy at approximately 74.10 J·mol−1. When the fuel has a higher cetane number, the combustion chemical reaction rate is faster and results in a more complete reaction. The active substance contact surface increases, which facilitates particulate matter oxidation.

Effects of Lubricating Oil Additives on the Microphysical Properties of Diesel Exhaust Particulate Matter

ABSTRACT In this work, experiments were performed on a diesel engine bench using different experimental fuels prepared by mixing diesel with three lubricating oil additives (LOAs), namely, an antioxidant, a detergent and a foam inhibitor. Diesel exhaust particulate matter (DEPM) samples were subsequently collected. The effects of the LOAs on the micromorphological and microstructural characteristics of the DEPM and its degree of graphitization were investigated using a combination of analytical methods (scanning electron microscopy, transmission electron microscopy and Raman spectroscopy) in conjunction with image processing software. The results showed the following: The DEPM diameter was determined by the polycyclic aromatic hydrocarbon (PAH) content of the fuel. Unburned PAHs caused the organic matter component of the DEPM to precipitate between the lamellae of its primary carbon particles (PCPs). The addition of the antioxidant to the fuel resulted in increased chemical heterogeneity of the DEPM. Furthermore, the D peak in the Raman spectrum of this DEPM had the highest intensity. The DEPM generated from combustion of the foam inhibitor-diesel fuel had the largest average PCP crystallite size; the addition of the foam inhibitor increased the degree of graphitization of the DEPM, and the graphite crystallites in this DEPM were the largest (4.65 nm). The DEPM generated from the combustion of the detergent-diesel fuel had the largest PCP interlayer spacing (mainly in the range of 0.42–0.44 nm). The LOAs did not significantly impact the C-C bond length in the DEPM graphite lattice.

Particle emission characteristics of DPF regeneration from DPF regeneration bench and diesel engine bench measurements

Diesel particulate filter (DPF) is an effective and state-of-the-art device to reduce the particle emission from diesel engines. Two experimental apparatuses, including a DPF regeneration bench and a diesel engine bench, were built to investigate the particle emission characteristics of DPF during the regeneration process in this work. The purpose of study is to explore the formation mechanism and influence factors of emitted particle. The DPF regeneration test bench measurements showed that some 10 nm nuclei model particles were blown out by high temperature inlet flow during DPF heating-up stage for each test regeneration temperatures. The particle concentration increased by 2–3 orders of magnitude due to this hot spot, and the mean diameter of the emitted particle rose from 10 to 20 nm to 300 nm. The diesel engine bench measurements indicated that the 10 nm nuclei model particle mainly came from the penetration of the inlet initial exhaust particles of diesel engine, and some of them originated from the blow-out of deposited soot layer during heating-up stage. The 10 nm nuclei model particle during regeneration process mainly originated from the oxidization of deposited soot layer inside DPF channels, and 100 nm aggregated model particle) were formed during this process simultaneously. The 8 g/L soot loading and the 575 °C regeneration temperature led to large total amount of emitted particles in the downstream of the DPF. Both 4 g/L and 8 g/L DPFs had moderate regeneration efficiencies and relative low total particle emission, when the regeneration temperature was 550 °C.

Exhaust emissions of diesel engines with nano-copper additives

The effects of nano-copper additives were investigated through a thermogravimetric (TG) test, diesel engine bench test, and road driving test. The tests demonstrated that the nano-copper additive presented a good catalytic effect on the combustion of soot particles, which reduced the complete combustion temperature from 580 to 520 °C. The diesel engine bench test showed that particulate matter (PM), CO, and HC emissions were reduced by 99.9%, 81.30%, and 33.33%, respectively. The NOx emissions slightly increased due to the lack of carbon as a reducing substance in the exhaust gas. The road driving test with a diesel vehicle demonstrated that more stringent emission standards can be met without any upgrade to the engine.

Simulation of the flow field and the chemical reaction coupling of selective catalytic reduction (SCR) system using an orthogonal experiment.

It is difficult to simulate both the flow field and the chemical reaction using, respectively, the flow state and kinetics calculations and actually reflect the influence of the gas flow state on the chemical change in a selective catalytic reduction (SCR) system. In this study, the flow field and the chemical reaction were therefore coupled to simulate a full Cu-Zeolite SCR system and the boundary conditions of the simulation were set by a relevant diesel engine bench test which included the exhaust temperature, the mass flow, and the exhaust pressure. Then, the influence of the gas flow state on the NOx conversion efficiency was investigated. Specifically, an orthogonal experimental design was used to study the influence of the injection parameters (position, angle, and speed) on the NH3 distribution by establishing the NH3 uniformity coefficient γ at the SCR catalyst capture surface in the flow field simulation. Then, the velocity capture surface of the SCR catalyst front section was sliced into coupled data transfer interfaces to study the effects of exhaust temperature, ammonia to NOx ratio (ANR), and the NO2/NOx on the NOx conversion efficiency. This was used as guidelines to optimize the SCR system control strategy. The results showed that a 1150 mm injection position, a 45°injection angle, and a 23 m/s injection velocity provided the most uniform NH3 distribution on the SCR catalyst capture surface. For constant injection parameters, the NOx conversion efficiency was the highest when the exhaust temperature was 200°C—400°C, the ANR was 1.1, and NO2/NOx was 0.5.

Effects of phenolic antioxidants on biodiesel oxidative stability and emission

Biodiesel is a high‐quality diesel alternative fuel, but it can get easily oxidized on long‐term storage. The addition of antioxidants can effectively improve the oxidation stability of biodiesel. In this study, the mechanism of phenolic antioxidants to inhibit the oxidation of biodiesel and reduce the NOX emission is discussed based on the experimental investigation. Antioxidants (0.8 wt%) 3‐tert‐butyl‐4‐methoxyphenol (BHA), rosemary (K1), and tea polyphenols (K2) were added to biodiesel B100. The antioxidant test was carried out at atmospheric temperature for 4320 h, and the peroxide value, acid values were measured. Then, 0.8 wt% of K1, K2, and BHA were added to B20, named as K1B20, K2B20, and BHAB20. The 186F diesel engine bench test was carried out under 10%, 25%, 50%, 75%, and 100% load at 3000 rpm, with HC, CO, NOX, and smoke emissions of various types of fuel (B20, BHAB20, K1B20, and K2B20) were measured. The results of antioxidant test showed that the antioxidant effect of rosemary was best, displaying a decrease in acid and peroxide values by 25% and 48%, respectively. The diesel engine bench test results showed that antioxidants had little effect on HC, CO, and smoke emission; however, the antioxidants significantly reduced NOX emission. The effect of natural antioxidant rosemary to reduce NOX emission is the best one. At 3000 rpm and 75% load, the NOx of B20 reduced by 9.4%. Among the three antioxidants, the experimental results verified the mechanistic analysis and provided the basis for the selection of antioxidants for biodiesel. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

Ammonium-Salt Formation and Catalyst Deactivation in the SCR System for a Marine Diesel Engine

Due to the low temperature and complex composition of the exhaust gas of the marine diesel engine, the working requirements of the selective catalytic reduction (SCR) catalyst cannot be met directly. Moreover, ammonium sulfate, ammonium nitrate, and other ammonium deposits are formed at low temperatures, which block the surface or the pore channels of the SCR catalyst, thereby resulting in its reduction or even its loss of activity. Considering the difficulty of the marine diesel engine bench test and the limitation of the catalyst sample test, a one-dimensional simulation model of the SCR system was built in this paper. In addition, the deactivation reaction process of the ammonium salt in the SCR system and its influencing factors were studied. Based on the gas phase and the surface reaction kinetics, the models of the urea decomposition, the surface denitrification, the nitrate deactivation, and the sulfate deactivation were both constructed and verified in terms of accuracy. Moreover, the formation/decomposition reaction pathway and the catalytic deactivation of ammonium nitrate and ammonium bisulfate, as well as the composition concentration and the exhaust gas temperature range were correspondingly clarified. The results showed that within a certain range, the increase of the NO2/NOx ratio was conducive to the fast SCR reaction and the NH4NO3 formation’s reaction. Increasing the exhaust gas temperature also raised the NO2/NOx ratio, which was beneficial to both the fast SCR reaction and the NH4NO3 decomposition reaction, respectively. Furthermore, the influence of the SO2 concentration on the denitrification efficiency decreased with the increase of the exhaust gas temperature because of increasing SCR reaction rate and reversibility of ammonia sulfate formation, and when the temperature of the exhaust gas was higher than 350 °C, the activity of the catalyst was almost unaffected by ammonia sulfate.

Dynamic Indicated Torque Estimation for Turbocharged Diesel Engines Based on Back Propagation Neural Network

An indicated torque estimation model is presented for turbocharged diesel engines considering both steady-state and transient operating conditions. The proposed model consists of two submodels: a steady-state indicated torque model and a transient torque coefficient model. By combining the steady-state torque with the transient torque coefficient from the two proposed submodels, dynamic indicated torque is obtained. The transient torque coefficient is calculated by training a designed back-propagation neural network (BPNN) using transient test data obtained from the designed experiments based on a DEUTZ BF6M1015 turbocharged diesel engine bench. Only the engine speed, the cycle fuel quantity and the intake air pressure are needed for dynamic torque estimation. The generalization capacity and dynamic torque estimation accuracy of the torque estimation model are validated. The maximum error of the estimated torque is within 8% while the average error is within 2% in both fuel step change and slow change conditions.

PALM OIL USE AS ADDITIVE TO FUEL FOR TRACTOR DIESELS

When environmental requirements for tractor diesels and changes in the price policy of various fuels of oil origin increase, there is a need to use new alternative flammable substancesfor partially or completely replace traditional fuels. Application of vegetable oils as combustible material for diesel engines is most perspective. One of the most competitive fuel is palm oil which world production exceeds many other vegetable oils, including rape. Advantages of palm oil allow to use it as fuel or as diesel fuel additive. The authors onsidered the main physical properties of palm oil for the purpose of assessment of its influence on the fuel equipment and a further possibility of its use in diesel engines. For assessment of characteristics of operation of the tractor diesel engine bench tests with additives of palm oil to diesel fuel were carried out. Experimental studies were carried out on an electric brake stand in tandem with a D-120 diesel engine. If oil additives reach up to 20 percent then combustion and quality of mixing woul change. The maintenance of CH decreases at low and normal loads to 42 percent, and at high ones – up to 17 percent. Concentration of carbon monoxides CO at the same time increases: at low and normal loads – by 37-49 percent, and in a maximum of loadings it increases by 6- 8 times and makes about 65 ppm. The content of nitrogen oxides NOx in exhaust gases at additive of palm oil significantly differs at high loadings and decreases by 21 percent or up to 4550 ppm. Soot emissions decrease in proportion to increase of content of palm oil in fuel: at 10 percentage additive by 20-30 percent and at 20 percent by 35-45 percent.

Interaction of diesel engine soot with NO2 and O2 at diesel exhaust conditions. Effect of fuel and engine operation mode

This work shows a study of the reactivity of twelve different types of soot with either NO2 or O2 under reacting conditions typically present in diesel particulate filters (DPFs). The soot samples were obtained from the combustion of four conventional and alternative fuels (diesel, biodiesel and two paraffinic fuels) in a diesel engine bench operated under three different engine operation modes: a typical urban-driving mode and two variations to this mode to assess the effect of the injection settings. The main objective of the work is to relate the oxidative reactivity of the soot to the nature and the origin of each sample. The possible simultaneous elimination of soot and NOx at typical diesel exhaust conditions is examined, as well. The reactivity tests were performed in a laboratory quartz gas flow reactor, discontinuous for the solid. The soot-NO2 interaction was studied with 200 ppm of NO2 at 500 °C and the soot-O2 interaction was studied with 5% O2 at 500 °C and 600 °C. The experimental results were used to determine the time needed for the complete conversion of carbon (τ) through the use of the equations of the Shrinking Core Model for solid-gas reactions with decreasing size particle and chemical reaction control. In general, the τ values show that the diesel fuel generates a less reactive soot than biodiesel or the alternative paraffinic fuels. In addition, increasing the injection pressure or adding a post-injection to the original injection strategy generates a more reactive soot. These findings point out that there is potential to achieve efficient regeneration processes in DPFs through other fuels than conventional ones and via engine calibration.