Small Diesel Engine Research Articles

Structural Performance Analysis and Optimization of Small Diesel Engine Exhaust Muffler

In recent years, the optimization of diesel engine exhaust mufflers has predominantly targeted acoustic performance, while the impact on engine power performance has often been overlooked. Therefore, this paper proposes a parallel perforated tube expansion muffler and conducts a numerical analysis of its acoustic and aerodynamic performance using the finite element method. Then, a Kriging model is established based on the Design of Experiments to reveal the impact of different parameter couplings on muffler performance. With transmission loss (TL) and pressure loss (PL) as the optimization objectives, a multi-objective optimization study is carried out using the competitive multi-objective particle swarm optimization (CMOPSO). The optimization results indicate that this method can simplify the optimization model and improve optimization efficiency. After CMOPSO calculation, the average TL of the muffler increased from 27.3 dB to 31.6 dB, and the PL decreased from 1087 Pa to 953 Pa, which reduced the exhaust noise and improved the fuel economy of the engine, thus enhancing the overall performance of the muffler. This work provides a reference and guidance for the optimal design of mufflers for small agricultural diesel engines.

Exploring the feasibility of dimethyl ether (DME) and LPG fuel blend for small diesel engine: A simulation perspective

There is a looming global crisis owing to the increase in greenhouse gases and the escalating fossil fuel process. The issue is further compounded by the ongoing conflicts in different places in the world. Hence, there is an urgent need for a bouquet of alternative fuels suitable to power the incumbent internal combustion engine. Among various options available Dimethyl Ether (DME) is a friendly environment fuel, easy to liquefy, and suitable for use in diesel engines, while Liquefied Petroleum Gas (LPG) is another potential alternative fuel suitable for internal combustion engines. The present study is an endeavor to investigate the characteristics of a diesel engine powered with DME-diesel blends as pilot fuel while LPG was used as the main fuel. During engine testing, different blends of diesel-DME were used containing 0%, 25%, 50%, and 75% DME. The AVL Boost software was employed for modeling the engine performance and tailpipe emission. The test fuel combination was successful in running the engine sans any abnormality in sound or performance. The results showed carbon monoxide (CO) and hydrocarbon (HC) emissions were reduced using the test fuel combination while there was a marginal increase in the oxides of nitrogen (NOx) levels. In general, the combination of DME and LPG could be considered as a potential and promising solution to reducing pollutant emissions.

A highly efficient and cost-effective liquid biofuel for agricultural diesel engines from ternary blending of distilled Yang-Na (Dipterocarpus alatus) oil, waste cooking oil biodiesel, and petroleum diesel oil

This study reports a highly efficient and cost-effective liquid biofuel for agricultural diesel engines by a ternary blending of waste cooking oil (WCO) biodiesel, distilled Yang-Na oil, and petroleum diesel oil. Biodiesel oil from WCO synthesized by NaOH-catalyzed pilot plant-scale solar reactor exhibited fuel properties that met ASTM-D6751 and EN-14214 standards. Crude Yang-Na was distilled at 280 oC to obtain distilled Yang-Na oil with major components of α-Gujernene (63.07 wt.%), α-Caryophyllene (19.08 wt.%), γ-Gujernene (5.16 wt.%), and γ-Elemene (5.23 wt.%), along with 7.46 wt.% of other hydrocarbon compounds. The ternary blendings of waste cooking oil (WCO) biodiesel, distilled Yang-Na oil, and petroleum diesel oil were formulated (50:30:20 and 50:25:25) and their physicochemical properties were evaluated and compared with a commercial B10 petroleum diesel oil. The formulated liquid biofuels met standards and closely resembled petroleum diesel with a viscosity of 3.86 cSt, density value of 876 kg m-3, and heating values of 9991 kcal/kg. The performance testing of the blended fuels in a small agricultural diesel engine showed the efficiency levels matched with a commercial B10 petroleum diesel oil and outperformed individual biodiesel and distilled Yang-Na oil. Variances in Brake Power and Brake Specific Fuel Consumption were <1% with low emissions of CO2, CO, HC, and NOx, while Engine Torque and biofuel consumption during cultivation showed differences of 3.42% and 2.54%, respectively. Accordingly, the obtained blended fuel is a promising option for community resource utilization, offering an alternative energy source for future communities.

Utilisation of Ethyl Levulinate as Diesel Fuel Additive

The world is going through a radical phase of energy conversion, due to both environmental and socio-economic factors, which will lead to a progressive transition from fossil to renewable energy sources. As regards the light land transport sector (cars), the abandonment of propulsion systems based on the use of internal combustion engines (ICEs) in favour of electrification seems the preferred solution. On the contrary, for heavy land (trucks and trains), marine and air transport sectors the path to follow is not yet clear.A possible alternative to fossil fuels is certainly represented by bio-fuels, which should allow a drastic reduction of CO2 emissions and, to a lesser extent, of CO and particulate matter. The use of bio-fuels does not involve a drastic change in the systems of distribution and use of energy, as the existing infrastructures can remain unchanged. In particular, second generation bio-fuels (obtained from non-food matrices) are attracting more and more attention and, among these ones, oxygenated alcohols obtained from residual lignocellulosic biomasses appear extremely promising for the use in diesel engine.The present study analyses the utilisation of ethyl levulinate (EL), a versatile second generation bio-fuel that can be used in Diesel/gasoline engines. EL can be conveniently obtained from the sustainable one-pot acid-catalyzed conversion of waste lignocellulosic feedstocks, employing bioethanol as the solvent/reagent.EL has been tested in a small DI Diesel engine, blended up to 25% by volume with a commercial Diesel fuel, without significative changes in engine performance, moderately increasing NOx and HC emissions but significantly lowering soot and CO emissions by more than 50%.

Experimental and Numerical Evaluation of an HCCI Engine Fueled with Biogas for Power Generation under Sub-Atmospheric Conditions

Energy transition to renewable sources and more efficient technologies is needed for sustainable development. Although this transition is expected to take a longer time in developing countries, strategies that have been widely explored by the international academic community, such as advanced combustion modes and microgeneration, could be implemented more easily. However, the implementation of these well-known strategies in developing countries requires in-depth research because of the specific technical, environmental, social, and economic conditions. The present research relies on the use of biogas-fueled HCCI engines for power generation under sub-atmospheric conditions provided by high altitudes above sea level in Colombia. A small air-cooled commercial Diesel engine was modified to run in HCCI combustion mode by controlling the air–biogas mixture temperature using an electric heater at a high speed of 1800 revolutions per minute. An experimental setup was implemented to measure and control the most important experimental variables, such as engine speed, biogas flow rate, intake temperature, crank angle degree, intake pressure, NOx emissions, and in-cylinder pressure. High intake temperature requirements of around 320 ∘C were needed to achieve stable HCCI combustion; the maximum net indicated mean effective pressure (IMEPn) was around 1.5 bar, and the highest net indicated efficiency was close to 32%. Higher intake pressures and the addition of ozone to the intake mixture were numerically studied as ways to reduce the intake temperature requirements for stable HCCI combustion and improve engine performance. These strategies were studied using a one-zone model along with detailed chemical kinetics, and the model was adjusted using the experimental results. The simulation results showed that the addition of 500 ppm of ozone could reduce the intake temperature requirements by around 50 ∘C. The experimental and numerical results achieved in this research are important for the design and implementation of HCCI engines running biogas for microgeneration systems in developing countries which exhibit more difficult conditions for HCCI combustion implementation.

Multi-Objective Optimization of the Structural Design of a Combustion Chamber of a Small Agricultural Diesel Engine Fueled with B20 Blend Fuel at a High Altitude Area

This study focuses on a small agricultural diesel engine fueled with B20 (20% biodiesel and 80% diesel by volume) blend fuel in a plateau area. The combustion chamber’s structural parameters and fuel injection angle were taken as variables at peak torque conditions. First, a full factorial design was used for experimental design. Second, the back-propagation (BP) neural network was employed to predict the indicated thermal efficiency and the indicated specific NOx emission. Third, the non-dominated sorting genetic algorithm-II (NSGA-II) was utilized to optimize the indicated thermal efficiency and the indicated specific NOx emission. Finally, the technique for order of preference by similarity to ideal solution (TOPSIS) method was applied to obtain optimal solutions, and a three-dimensional numerical simulation was conducted to verify the optimization results. The optimization results indicate that the shape characteristics of the combustion chamber have a certain influence on the engine’s performance. The optimized design significantly reduces NOx emissions, by 22.83%, compared to the original engine, whilst maintaining the engine’s performance.

Analysis of an innovative combustion chamber with the wall guided fuel injection in a small diesel engine

This paper has included the effects of different bowl geometries which has the wall guided fuel injection. Bowl geometries, which affect in-cylinder air flows, have a great influence on the change of mixture formation. Also, the region where the fuel hits in the bowl affects all engine parameters. In this presented numeric study, the standard combustion chamber geometry of a single-cylinder, air-cooled, and direct-injection diesel engine is compared with the designed new combustion chamber. Four different rotation angles (0°, 7.5°, 10°, and 15°) were determined for the new combustion chamber geometry and compared with the standard geometry. The three-dimensionally modeled bowl geometries in 3D Computational Fluid Dynamics simulation were examined in terms of in-cylinder pressure and temperature, instantaneous and cumulative heat release rate, exhaust emissions (NO, soot, CO, and CO2), temperature/spray, and equivalence ratio/spray at different CA’s. The effects of the different rotation angles of the designed new bowl geometry on both the air movement and the region where the fuel hits were investigated for the engine parameters. When the results obtained are examined, maximum in-cylinder pressures for standard combustion chamber, new combustion chamber 1, new combustion chamber 2, new combustion chamber 3, and new combustion chamber 4 geometries were obtained 79.5, 75.2, 78, 78.1, and 78 bar respectively, and the maximum in-cylinder temperatures were found 1766, 1742, 1805, 1817, and 1818 K, respectively. According to the results obtained from the numerical analysis, CO, CO2, and soot emissions decreased while NO emissions increased in the new combustion chamber, compared to the standard combustion chamber. Examined the spray distributions in bowl, it was seen that the fuel sprays distributed more homogeneously and flame propagates which is spread throughout the chamber in the new combustion chamber type, which improved the mixture formation. The wall guided fuel flow in the novel designed chamber geometries beneficial to turbulence kinetic energy, spray distribution, emissions.

Evaluation of the environmental and cost impact of a small diesel engine with ethanol-diesel and isopropanol-diesel fuel at varying engine loads and speeds

Nowadays, alcohol additives such as ethanol and isopropanol are used to minimize emissionsresulting from combustion in diesel engines. While these blends contribute to reducing emission values, itis also important to consider their environmental and cost implications. Therefore, this experimental studyfocuses on the emission characteristics and the environmental and cost impact of alcohol additives in dieselfuel. The experiments were conducted at low and medium engine torques (3 Nm and 6 Nm) and variousengine speeds (1000, 1500, 2000, and 2500 rpm). Additionally, three different test fuels were used in theexperiments, including standard diesel fuel, as well as diesel fuel with volumetric additions of 7% ethanol(E7) and 7% isopropanol (IP7) alcohol additives. The emission values of all test fuels were measured, andan analysis of environmental influence and cost was conducted. Upon examining the results, it is evidentthat the addition of alcohol to diesel fuel significantly increased the environmental influence and cost atlow engine speeds, while it led to a decrease at high engine speeds. Furthermore, the increase in engineload contributed to emission reduction due to higher combustion temperatures, thereby contributing to adecrease in both cost and environmental influence.

Experimental Investigation of Heat Transfer in a Flat-wall Impinging Diesel Spray Flame under Diesel-like Conditions

The heat loss through the walls of Internal Combustion Engines (ICEs) needs to be minimized and improved since it has a detrimental impact on the overall thermal efficiency of the engine. This study focuses on investigating heat transfer in a flat-wall impinging diesel spray flame, simulating diesel conditions, to optimize engine parameters. The effects of factors such as various injection pressures, nozzle hole diameters, impingement distances, and oxygen concentrations are analysed in combined and individually. Experimental techniques, such as high-speed imaging, heat flux sensors, and thermocouples, are used to visualize spray flame, measure heat flux profiles and temperature distributions, respectively. Preliminary results and their implications on heat transfer and heat loss are discussed. Regarding the parametric studies investigating the effect on wall heat loss under conditions similar to those of a small diesel engine, it was observed that the transferred heat on the wall was significant in certain conditions. These results emphasize the effectiveness of manipulating the injection rate profile as a viable step to suppress the heat transfer through the wall.

A PROPOSAL FOR A HYBRID POWER TRAIN FOR A TRUCK

Aiming at reducing the emission of pollutants from automotive vehicles, international commissions indicate, at each given period, a target of admissible values for these pollutants, to be implemented by the automakers. A case like the future implementation of EuroVII, from 2025, in European regions. In parallel to these conditions, there are many studies with the objective of seeking alternatives for the propulsion of these combustion vehicles, for example, the application of fully electric or hybrid vehicles. This article aims to develop and implement a mathematical model for a proposal for a hybrid engine, in a low-power truck, resulting in a small diesel engine, powering the vehicle's alternator and battery, generating the charging for use in a main electric motor, that is, to develop with a focus on energy conservation and the environment, with a reduction in the size of a combustion engine and its emissions.

Experiment Study on the Exhaust-Gas Heat Exchanger for Small and Medium-Sized Marine Diesel Engine

This paper aims to design a special exchanger to recover the exhaust gas heat of marine diesel engines used in small and medium-sized fishing vessels, which can then be used to heat water up to 55°C–85°C for membrane desalination devices to produce fresh water. A new exhaust-gas heat exchanger of fins and tube, with a reinforced heat transfer tube section, unequal spacing fins, a mixing zone between the fin groups and four routes tube bundle, was designed. Numerical simulations were also used to provide reference information for structural design. Experiments were carried out for exhaust gas waste heat recovery from a marine diesel engine in an engine test bench utilizing the heat exchanger. The experimental results show that the difference between heat absorption by water and heat reduction of exhaust gas is less than 6.5%. After the water flow rate was adjusted, the exhaust gas waste heat recovery efficiency was higher than 70%, and the exhaust-gas heat exchanger’s outlet water temperature was 55°C–85°C at different engine loads. This means that the heat recovery from the exhaust gas of a marine diesel engine meets the requirement to drive a membrane desalination device to produce fresh water for fishers working in small and medium-sized fishing vessels.

Renewable energy approach towards powering the CI engine with ternary blends of algal biodiesel-diesel-diethyl ether: Bayesian optimized Gaussian process regression for modeling-optimization

The present study investigates the performance and emissions of a small diesel engine powered with ternary blends of algal biodiesel, diesel, and diethyl ether. The findings indicate that the addition of diethyl ether improved the brake thermal efficiency, peak pressure inside cylinder, and net heat release rate. This is because the additives have a greater oxygen value, higher cetane number, and volatility. However, an increase in NOX emissions was observed. Gaussian Process Regression, a modern supervised machine learning approach, was utilized to develop a prognostic model for the engine's performance and exhaust emission. The Bayesian technique for hyperparameter optimization was used to strengthen the predictive model's training process. As model input parameters, engine load, fuel mixing ratio, and fuel injection pressure were used. The response variables were brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), NOx, HC, and CO. The created prophetic models predicted engine performance and exhaust emission data with high accuracy, as shown by correlation coefficient values ranging from 0.9746 to 0.9999, low mean squared error up to only 11.023, and low mean absolute error ranging from 0.001 to 2.591. The prognostic model for engine performance and emission developed with Bayesian optimized Gaussian process regression could provide a robust simulation and prognostication efficiency.

Performance and Emission of Diesel Engine Fuelled by Commercial Bio-Diesel Fuels in Indonesia

Abstract The performance and emission of a small diesel engine fuelled by commercial diesel fuel in Indonesia are present in this paper. Various commercial diesel fuels in Indonesia are produced and marketed by Pertamina. As the largest oil company in Indonesia, Pertamina has developed various diesel fuels, namely Solar, Biosolar (B30), Dexlite, and Pertadex. This study explains in more detail the performance, fuel consumption, and emission produced by the four types of fuels, and they were investigated experimentally using a single-cylinder diesel engine at various engine speeds, from 1,000 rpm to 4,500 rpm. The result shows the engine fuelled by Pertadex generates the highest power and torque, while the lowest is generated by the Biosolar fuelled engine. The maximum torque and power generated by the Pertadex fuelled engine are about 25.5 Nm and 7200 W, respectively. The engine fuelled by Pertadex has the lowest brake specific fuel consumption (BSFC) of 0.3037 kg·kW·h, compared to the engines fuelled by the Dexlite, Solar, and Biosolar fuels, with values around 0.3127, 0.3215, and 0.3338 kg·kW·h, respectively. At the same time, the measurement of gas emissions, including CO2, CO, NOx, and HC was conducted simultaneously.

Experimental Combustion Analysis of a Small Size Diesel Engine Fueled With Tire Derived Fuel/Diesel Fuel Blends

This study aims to analyse the detailed combustion characteristics of tire derived fuel blends (TDF) in small-size DI diesel engines. From this point of view, the refined TDF and reference diesel fuel (No.2 Diesel) were blended in various percentages and tested in a single cylinder naturally aspirated DI diesel engine to clarify its detailed combustion characteristics. The experimental test results point out that ignition delay period is ob-served to be 4.32 CAD (No.2 Diesel fuel), 5.57 CAD (TDF20), 6.56 CAD (TDF40), 8.48 CAD (TDF60), 11.09 CAD (TDF80), and 14.26 CAD (TDF100) for the low engine speeds (1400 rpm). With the increasing TDF in fuel blends and engine speed, the ignition delay period prolongs more, and the total combustion duration shortens. However, due to the excessively long ignition delay period of TDF100, it is not possible to run the test engine at more than 3000 rpm. TDF blends usually demonstrate a longer premixed combustion period than that of No.2 Diesel, while it exhibits a shorter diffusive combustion period. TDF blends also display a higher maximum value of heat release rate (HRRmax), a higher peak value of in-cylinder pressure (Pmax) and a higher rate of pressure rise (dP/dCAD). In addition, combustion events occur late, and the center of combustion moves away from the top dead center into expansion stroke in the case of TDF blends.

Nucleation-accumulation mode trade-off in non-volatile particle emissions from a small non-road small diesel engine.

Small (< 8kW) non-road engines are a significant source of pollutants such as particle number (PN) emissions. Many small non-road engines do not have diesel particulate filters (DPFs). They are so designed that air-fuel ratio (AFR) can be adjusted to control visible diesel smoke and particulate matter (PM) resulting from larger accumulation mode particles. However, the effect of AFR variation on smaller nucleation mode nanoparticle emissions is not well understood. Several studies on larger engines have reported a trade-off between smaller and larger particles. In this study, AFR was independently varied over the entire engine map of a naturally aspirated (NA) non-road small diesel engine using forced induction (FI) of externally compressed air. AFR's ranged from 57 to 239 compared to the design range of 23-92 for the engine, including unusually high AFR's at full-load operation, not previously reported for conventional combustion. As expected, larger accumulation mode particles were lowered (up to 15 times) for FI operation. However, the smaller nucleation mode nanoparticles increased up to 15 times. Accumulation mode particles stopped decreasing above an AFR threshold while nucleation particles continuously increased. In-cylinder combustion analysis showed a slightly smaller ignition delay and higher burn rate for FI cases relative to NA operation. Much higher peak cylinder pressures were accompanied by much lower combustion and exhaust gas temperatures (EGT), due to higher in-cylinder mass during FI operation. Peak nucleation mode emissions were shown to be negatively correlated to EGT for all the data, collapsing on a single curve. This is consistent with some other studies reporting increased nucleation mode emissions (and higher accumulation mode particles) with decreased load, lower speed, lower EGR, advanced combustion phasing, and higher injection pressure, all of which reduce EGT. The nucleation-accumulation trade-off has been explained by the 'adsorption hypothesis' by some investigators. In the current work, an alternative/supplemental argument has been made for the possibility that lower cylinder temperatures during the late-burning phase (correlated to lower EGT) phase hampers oxidation of nucleation mode particles and increases nucleation mode emissions.

Wrong Injection Detection in a Small Diesel Engine, a Machine Learning Approach

In the last ten years, Machine Learning (ML) and Artificial Intelligence (AI) have overwhelmed every engineering research branch finding a broad variety of applications; anomaly detection and anomaly classification are two of the topics that have benefited mostly by data-driven methods’ insights. On the other side, in the small diesel engine domain, the current trend is to lean on traditional anomaly detection/classification procedures and do not foster the use of AI. The goal of this work is to detect anomalies in the in-cylinders injectors of a small diesel engine as soon as a wrong quantity of fuel is inputted into one or more cylinders by means of ML approaches. Part of the analysis aim to understand which measurements are the most relevant for the detection and to compare different techniques to select the most suitable one. Furthermore, a condition-based methodology for maintenance is proposed. After a brief review of the state-of-the-art, the case study scenario is presented grouping sensors accordingly to their degree of accessibility; then, the implemented techniques are explained, and results are discussed.

Computational Investigation on the Performance Increase of a Small Industrial Diesel Engine Regarding the Effects of Compression Ratio, Piston Bowl Shape and Injection Strategy

This paper describes the simulative approach to calibrate an already extremely highly turbocharged industrial diesel engine for higher low-speed torque. The engine, which is already operating at its cylinder-pressure maximum, is to achieve close to 30 bar effective mean pressure through suitable calibration between the compression ratio, piston-bowl shape and injection strategy. The basic idea of the study is to lower the compression ratio for even higher injection masses and boost pressures, with the resulting disadvantages in the area of emissions and fuel consumption being partially compensated for by optimizations in the areas of piston shape and injection strategy. The simulations primarily involve the use of the 3D CFD software Converge CFD for in-cylinder calibration and a fully predictive 1D full-engine model in GT Suite. The simulations are based on a two-stage turbocharged 1950 cc four-cylinder industrial diesel engine, which is used for validation of the initial simulation. With the maximum increase in fuel mass and boost pressure, the effective mean pressure could be increased up to 28 bar, while specific consumption increased only slightly. Depending on the geometry, NOx or CO and UHC emissions could be reduced.

A Comprehensive Study on the Effect of Dimethyl Carbonate Oxygenate and EGR on Emission Reduction, Combustion Analysis, and Performance Enhancement of a CRDI Diesel Engine Using a Blend of Diesel and Prosopis juliflora Biodiesel

This paper examines the combined effects of ignition improvers (DMC) and EGR on the CRDI small single-cylinder diesel engine’s performance, combustion, and emissions. In this experimentation, 20% (B20) optimal mix of Prosopis juliflora oil biodiesel (PJOB) and 5 ml dimethyl carbonate (DMC) additive was used as test fuel. The fuel handling CRDI system factors such as injection pressure set at 600 bar and injection timing set to 21 (bTDC) with a compression ratio of 16 were considered for the study. For the EGR trial, 20% of the exhaust gas was recirculated under various BMEP circumstances. The test was performed with and without EGR and DMC additive conditions like (i) diesel @ 0% EGR, (ii) diesel + 5 ml DMC @ 20% EGR, (iii) B20 @ 0% EGR, and (iv) B20 + 5 ml DMC @ 20% EGR at the engine power output. The amalgamation of dimethyl carbonate (DMC) additives and EGR reduces NOx and smoke while increasing CO and HC emissions. In addition, the DMC additive and EGR improve thermal efficiency slightly. The overall clubbing of DMC additive and EGR rate indicates better performance for the selected factors than a CRDI engine with a six-hole conventional mechanical fuel injection system. The outcome of the work clearly demonstrates that both the 5 ml DMC additive and the 20% EGR rate of the B20 blend show optimum values of BTE, BSFC, and EGT of 32.93%, 0.27 kg/kw·hr, and 310.89°C, which is closer to diesel. Factors of combustion like cylinder peak pressure (CPP) and heat release rate (HRR) are 70.93 bar and 58.13 J/deg. The tailpipe exhaust of NOx and smoke is 1681 ppm and 31.30 (% vol), which is less than diesel. The HC and CO levels are 93 ppm and 0.38 (% vol), respectively, which are significantly higher than diesel fuel.

Evaluation of small off-road diesel engine emissions and aftertreatment systems

Off-road engines represent one of the largest categories for mobile source emissions in the United States. Emissions standards for small off-road diesel engines (SORDEs), which have not been updated since 2004, can be met without the use of aftertreatment on engines below 75 horsepower (hp) for nitrogen oxides (NOx) or below 25 hp for particulate matter (PM). It has been well established that aftertreatment systems can significantly decrease mobile source emissions, and improvements in these technologies since 2004 could warrant consideration for adopting more stringent standards for the SORDE category. This study evaluated the feasibility, efficiency, durability, and cost benefit of implementing regulations strict enough to require the use of selective catalytic reduction (SCR) and diesel particulate filter (DPF) controls on off-road engines under 75 hp. Durability testing was performed and emissions assessed on four stock engines equipped with retrofitted aftertreatment systems. The results suggest adding a DPF can provide >98% PM reductions. SCR systems provided NOx reductions ranging from 26 to 91% largely dependent on the cycle tested and engine exhaust temperature profile. Adoption of new SORDE standards could provide a PM reduction of 3.8% and a NOx reduction of 8.8–13.7% for the total off-road equipment inventory in California.

Optimization of combustion parameters for CRDI small single cylinder diesel engine by using response surface method

Limited fossil fuel’s reservoir capacity and pollution caused by them are the big problem today in the world. The small diesel engine, working with a conventional fuel injection system was the major contributor to this. The current study represented a statistical investigation of such a small diesel engine. A mechanical fuel injection system of the small diesel engine was retofitted with a simple version of the electronic common rail diesel injection (CRDI) system in the present study. The effect of combustion parameters such as compression ratio (CR), injection pressure (IP) and start of injection timing (IT) was considered in the study. The study was performed to optimize these parameters with respect to performance and emission aspects. The reduction in parameters such as carbon monoxide (CO), nitrogen oxides (NOx), smoke and hydrocarbon (HC) from engine exhaust gases were considered in the emission aspect. Improve brake thermal efficiency (BTE) and fuel economy was considered in the performance aspect. The response surfaced method (RSM) was used to optimise these combustion parameters. The regression equations were obtained for measurable performance and emission parameters using the RSM model. The surface plots derived from the regression equations were used to analyse the effect of considered combustion parameters. Diesel injected at a pressure 600 bar, with retarded injection timing 15° crank angle (CA) before top dead center (bTDC) and compression ratio set at 15 was found to be optimum for this CRDI small diesel engine. The further validation of optimum parameters was done by conducting a confirmatory test on the engine. The maximum error in prediction was found to be 2.7%, which shows the validation of the RSM model.