Exhaust System Of Diesel Engine Research Articles

Analysis of Recovery Power, Saved Fuel, Emissions, and Economy in Diesel Engines Operating with Thermoelectric Generators

Thermoelectric generators are a potential alternative to improve the performance of internal combustion engines. In this research, an analysis of the energy recovery capacity, fuel-saving, emission reduction, and economic analysis of a thermoelectric generator located in the exhaust system of a stationary diesel engine has been carried out. For the experimental tests, three types of fuels (D100%, BP5%, and BP10%) have been used, as well as changes in the conditions of torque (3 – 6 Nm) and rotational speed (3000 – 3800 rpm) of the engine. The results show a recovery capacity of 55.5 W, 66.5 W, and 70.6 W for fuels D100%, BP5%, and BP10%, representing recovered energy of 2.33%, 2.78%, and 2.96% compared to the output power of the engine. The use of the thermoelectric generator has allowed achieving fuel savings of 2.9%. The implementation of the TEG implies a reduction in emissions (CO2, HC, and NOx) of 1.61%, 1.82%, and 2.07% for D100%, BP5%, and BP10% fuels. Economic savings of 528 USD/kWh (36 months) have been achieved, showing the technology's potential, especially in high-power engines or regions with high fuel costs. Future studies will focus on improving the thermoelectric generator's recovery capacity.

3D AND 1D SIMULATIONS OF DIESEL PARTICULATE FILTER (DPF)

DPF is an important device in the exhaust system of Diesel engine. In this paper we simulate velocity and pressure distributions in DPF to determine kinematic and hydraulic characteristics. This will provide the basis for designing and selecting size of channels in DPF. Numerical simulations were made using ANSYS Fluent commercial software and OpenFOAM open-source software. The results show that the difference between the two softwares is negligible. A compact 1D mathematical model developed based on the Darcy equation, momentum equation and continuity equation. The mathematical model solved by shooting method for boundary value problem. Simulation results from 1D and 3D approaches are very coincident.

Platinum Recovered from Automotive Heavy-Duty Diesel Engine Exhaust Systems in Hydrometallurgical Operation

The current study is focused on platinum recovery from the secondary sources of end-of-life heavy-duty diesel oxidation catalysts (DOCs) and heavy-duty catalyzed diesel particulate filters (c-DPFs) in order to reduce the supply–demand gap within the European Union. The extraction of platinum was based on a hydrometallurgical single-step low acidity leaching system (HCl-H2O2-NaCl) and a calcination step that takes place before the leaching process. The parameters of calcination and leaching process were thoroughly investigated in order to optimize recovery efficiency. The optimized results proved that a calcination step (at 800 °C for 2 h) improves the recovery efficiency by a factor of 40%. In addition, optimal Pt recovery yield was achieved after 3 h of leaching at 70 °C, with a solid-to-liquid (S/L) ratio of 70 g/100 mL (70%) and 3 M HCl-1% vol H2O2-4.5 M NaCl as leaching conditions. The optimum Pt recovery yield was 95% and 75% for DOC and c-DPF, respectively. Since the secondary feedstock investigated is highly concentrated in platinum, the pregnant solution can be used as a precursor for developing new Pt-based catalytic systems.

One-Dimensional Gas Flow Analysis of the Intake and Exhaust System of a Single Cylinder Diesel Engine

In order to design a diesel engine system and to predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. Gas flow analysis in a three-dimensional (3D) format needs a high-resolution workstation and an enormous amount of time for analysis. Calculation using the method of characteristics (MOC), which is a gas flow analysis in a one-dimensional (1D) format, has a fast calculation time and can be analyzed with a low-resolution workstation. However, there is a problem with poor accuracy in certain areas. It was assumed that the reason was that 1D could not implement the shape. The error that occurs in the shape of the bent pipe used in the intake and exhaust ports of the diesel engine was analyzed and to find a solution to the low accuracy, the results of the experiment and 1D analysis were compared. The discharge coefficient was calculated using the average mass flow rate, and as a result of applying it, the accuracy was improved for the maximum negative pressure by 0.56–1.93% and the maximum pressure by 3.11–7.86% among the intake pipe pressure results. The difference in phase of the exhaust pipe pressure did not improve. It is considered as a limitation of 1D analysis that does not improve even by applying the discharge coefficient. In the future, we intend to implement a bent pipe that cannot be realized in 1D using a 3D format and to prepare a method to supplement the reliability by using 1D–3D coupling.

Research on Densification Mechanism of Hot Isostatic Pressing Technology in Nickel-Based Superalloys for Marine Environment

Jiang, Z.; Wang, J., and Cao, D., 2020. Research on densification mechanism of hot isostatic pressing technology in nickel-based superalloys for marine environment. In: Wan, Z. (ed.), Coordinated Sustainable Development in Coastal Areas: Environment and Economy. Journal of Coastal Research, Special Issue No. 109, pp. 100–104. Coconut Creek (Florida), ISSN 0749-0208.Nickel-base superalloy is one of the major materials employed in the manufacturing process of air valve and exhaust system of diesel engine, turbine disk and blade of gas turbine and nuclear power units. The rapid development of modern marine industry is inseparable from the rapid improvement of comprehensive properties of superalloy. In this process, hot isostatic pressing (HIP) technology has been playing a significant role in the application of Nickel-base superalloy. In this paper, the research and application of HIP technology in the field of Nickel-base superalloy are herein summarized, and concluding the effect of HIP technology on densification mechanism and properties of cast superalloy.

Available Energy in Cars’ Exhaust System for IoT Remote Exhaust Gas Sensor and Piezoelectric Harvesting

The exhaust system of the light-duty diesel engine has been evaluated as a potential environment for a mechanical energy recovery system for powering an IoT (Internet of Things) remote sensor. Temperature, pressure, gas speed, mass flow rate have been measured in order to characterize the exhaust gas. At any engine point explored, thermal energy is by far the most dominant portion of the exhaust energy, followed by the pressure energy and lastly kinetic energy is the smallest fraction of the exhaust energy. A piezoelectric flexible device has been tested as a possible candidate as an energy harvester converting the kinetic energy of the exhaust gas flow, with a promising amount of electrical energy generated in the order of microjoules for an urban or extra-urban circuit.

Evaluation of Catalysts Derived from Palm Kernel Shell Carbon in a Passive NOx Removal from a Diesel Engine Exhaust

Carbon-supported de-NOx catalysts have attracted much attention lately due to their reactivity at low temperature, where it is usually challenging to remove NOx from mobile emission sources such as light-duty diesel-powered vehicles. In addition, passive mode of NOx removal system is preferable due to the absence of a reductant injection requirement, which could add an extra cost to the system. Palm kernel shell activated carbon (PKS) was used to synthesize SCR catalysts by precipitating manganese (Mn) and/or cerium (Ce) oxides. The catalysts were characterized using nitrogen adsorption-desorption experiment, X-ray fluorescence analysis (XRF), hydrogen temperature-programmed reduction (H2-TPR) and Fourier-Transform infrared spectroscopy (FTIR). The experiment of NOx removal from a real diesel engine exhaust system revealed that Mn/PKS exhibited the highest NOx removal at 74% and at the lowest temperature of 140 °C. This was attributed to the high surface area and micropore volume, high metal loading, enhanced hydroxyl and carbonyl functional groups and the presence of reducible MnO2 species. Therefore, it is expected that this type of catalyst may serve as a cost-effective material for a sustainable alternative to the current practice in removing NOx from diesel engine vehicles.

Application of the DOC-DPF Integrated Exhaust Particle Treatment Device for New Marine Diesel Engines

Based on the analysis of the diesel engine post-processing technology line, a DOC-DPF tail gas treatment device is proposed. The exhaust system of marine diesel engine is reformed, the particulate matter purification test is carried out in the exhaust system installation DOC-DPF tail gas treatment device, and the exhaust particulate matter of the marine diesel engine is detected by the automatic smoke tester and other instruments. The results show that the new ship exhaust particulate disposal device can effectively reduce particulate emissions from ship exhaust and is suitable for ships.

Coupled simulation of a thermoelectric generator applied in diesel engine exhaust waste heat recovery

This work develops a heat transfer model of a thermoelectric generator to explore the coupled relationship between high temperature exhaust flows, structure, and the external cooling air. The coupled heat transfer results showed that the fins reached a uniform high temperature, for the rated speed, the average temperature is 474 K. The coupled design scheme of the thermoelectric generator tested by installing it in a 4-cylinder turbocharged Diesel engine exhaust system. Comparison of the test and simulation results showed that as engine speed in-creased, the inlet and outlet exhaust temperatures of the thermoelectric generator exhibited a parabolic trend increase. The cooling water outlet temperature and the top, middle, and bottom fin temperatures increased linearly, and the coupled model was verified. From idle speed to rated speed, the top, middle, and bottom fin temperatures increased from 458 K to 476 K, 417 K to 463 K, and 406 K to 449 K, respectively; the cooling water outlet temperature increased from 293.6 K to approximately 303 K. Hence, the thermoelectric components installed in fins can experience temperature differences of over 100 K, the heat transfer efficiency can increase which ensures consistent output performance of the thermoelectric generator based on coupled design between the heat exchanger and thermoelectric modules array column.

Concept of using the heat pipes in the heat exchanger of diesel engine exhaust system intended for use in potentially explosive atmospheres

Limiting the temperature of exhaust gases to below 150°C is one of the necessary conditions for diesel engine to be used in a potentially explosive atmosphere. For this purpose heat exchangers are necessary to be used. This article presents the concept of exchanger in which heat pipes are used to transport thermal energy from the exhaust gases to the cooling medium.

An electrochemical model of an amperometric NOx sensor

To help design future amperometric NOx sensors, a physics-based sensor model that includes diffusion and electrochemical submodels is developed. It is shown that NO is partly reduced in the O2 sensing chamber which affects NO concentration in the O2 sensing and in the NOx sensing chamber. Therefore, the electrochemical model is developed to simulate partial reduction of NOx on the O2 sensing electrode and reduction of NOx on the NOx sensing electrode. A transport model that simulates diffusion of the gas species through the sensor diffusion barriers and sensor chambers is coupled to the electrochemical submodels. A fully controlled sensor test-rig that provides controlled gas mixtures is employed to carry out experiments to estimate model parameters. Then, the sensor is installed on the exhaust system of a medium duty Diesel engine and then on a port injection spark ignition engine. Experiments at different engine operating conditions with different NOx concentrations from 0 to 2820 ppm have been performed to validate the model accuracy at different operating conditions. Through the validation process, the NOx sensing cell voltage is changed experimentally at different NOx concentrations to evaluate the model accuracy at different cell voltages. The model results closely match the experiments with the maximum 12% error for the NOx sensing pumping current.

Direct estimation and experimental validation of the acoustic source characteristics of turbocharged diesel engine exhaust system

The present study aims at application of the novel direct method developed by Kumar and Munjal for naturally aspirated engines [Applied Acoustics 135, 70–84 (2018)] to the turbocharged engine’s exhaust system for estimation of acoustic source characteristics. In this paper, transfer matrices of the turbine and compressor of an automotive turbocharger are derived. Mass continuity across the turbine and compressor along with the respective static pressure ratios are used for deriving their transfer matrices. The acoustic source characteristics of each cylinder for the source-load junction downstream of the exhaust valve/s is computed assuming that the cylinder discharges to the ideal pressure release boundary condition with the constant pressure being product of the turbine pressure ratio and mean pressure in the exhaust pipe downstream of the turbine. Source characteristics of each cylinder are used to estimate the source characteristics downstream of the exhaust manifold. Using the derived transfer matrix of the turbine, the source characteristics are further estimated at the source-load junction downstream of the turbine. Finally, the estimated source characteristics of the engine downstream of the turbine are used to predict the unmuffled sound pressure level (SPL) spectrum which is shown to compare reasonably well with the experimentally measured values. Importance of acoustic modelling of the turbine is highlighted by comparing the SPL spectra predicted using the estimated source characteristics with and without the turbine. The estimated source characteristics and unmuffled approximate SPL spectrum of a turbocharged engine being thus known at the engine’s inception stage, the present study can be used for the integration of design and analysis of the engine and muffler.

Design of Fault Simulation Software for Intake and Exhaust System of Marine Diesel Engine

Aiming at the problems of high operating cost, high training cost and large site requirement of traditional marine engine platform, the software of fault diagnosis system for marine diesel engine intake and exhaust system is developed by using Visual Studio 2012 platform. The relevant mathematical model is established by numerical method, and the conversion from mathematical model to code is realized to simulate the working status of marine intake and exhaust system in normal operation and failure. The results show that the simulation system runs well with low cost and small site requirement. It can accurately simulate the normal operation and fault state of the ship intake and exhaust system. It can be used for training work and improve the actual response ability of the trainers to the fault of the ship intake and exhaust system.

Optimum design for intake and exhaust system of a heavy-duty diesel engine by using DFSS methodology

In this study, an optimum design for intake and exhaust system of a heavy-duty diesel engine was conducted by using the well-known design for six sigma (DFSS) methodology. As a result of this work, the NOx emission regulation has been successfully satisfied while minimizing the fuel consumption. On the basis of this DFSS work, the design robustness of the engine system was also enhanced. Hence, it is expected that the final design proposal would reduce the variability in brake thermal efficiency (BTE) that could be caused by the harsh environment and the system aging. Especially, this work has successfully raised the amount of exhaust gas recirculation (EGR) up to the target level by adopting the venturi tubes in the intake and exhaust lines. In this study, engine cycle simulation technique was employed to assess the effect of the various design parameters and the final design proposal was verified through a real engine test. The current optimum design work has considered four control factors such as the size of turbocharger, the diameter of intake and exhaust venturi pipes, and the efficiency of EGR cooler. Here, an L9 orthogonal array was employed to efficiently choose the best design proposal among 81 design combinations (i.e., four independent control factors which individually have three different levels).

Simulating Real World Soot-Catalyst Contact Conditions for Lab-Scale Catalytic Soot Oxidation Studies

In diesel soot oxidation studies, both well-defined model soot and a reliable means to simulate realistic contact conditions with catalysts are crucial. This study is the first attempt in the field to establish a lab-scale continuous flame soot deposition method in simulating the “contact condition” of soot and a structured diesel particulate filter (DPF) catalyst. The properties of this flame soot were examined by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM) for structure analysis, Brunauer-Emmett-Teller (BET) for surface area analysis, and thermogravimetric analysis (TGA) for reactivity and kinetics analysis. For validation purposes, catalytic oxidation of Tiki® soot using the simulated contact condition was conducted to compare with the diesel particulates collected from a real diesel engine exhaust system. It was found that the flame soot is more uniform and controllable than similar samples of collected diesel particulates. The change in T50 due to the presence of the catalyst is very similar in both cases, implying that the flame deposit method is able to produce comparably realistic contact conditions to that resulting from the real exhaust system. Comparing against the expensive engine testing, this novel method allows researchers to quickly set up a procedure in the laboratory scale to reveal the catalytic soot oxidation properties in a comparable loose contact condition.

Direct estimation and experimental validation of the acoustic source characteristics of two-cylinder naturally aspirated diesel engine exhaust system

In this paper, acoustic source characteristics of the exhaust system of two-cylinder naturally aspirated engines are estimated using a novel direct method. Each cylinder (the cylinder cavity and exhaust valve) is a non-linear time-variant acoustic source for the exhaust system. The source impedance of each cylinder is estimated assuming that the other cylinder is not exhausting at the same time. In order to work with linear time-invariant model of the acoustic source, the impedance of each cylinder is assumed as the reciprocal of source admittance averaged over different crank-angle steps. The source pressure is product of acoustic mass velocity at the source-load junction and the sum of the source impedance and the load impedance. Computation of source impedance and acoustic mass velocity calls for the aero-thermodynamic computation in the time-domain making use of the values of pressure and temperature of the in-cylinder gas at the exhaust valve opening (EVO) along with the basic geometrical details of the cylinder, intake and exhaust valves and ports. The estimated source characteristics for each cylinder at the downstream of exhaust valve are then transferred downstream to the end of the runner. The source characteristics so obtained are then combined for the two cylinders. These values are then transferred to the beginning of the acoustic test load (exhaust pipe or exhaust muffler). The estimation of source characteristics is dependent on the exhaust mass flow rate which depends on the exhaust system to which cylinders are discharging. Thus, the IC engine acoustic source is load-dependent, not unique. Yet, the resultant source characteristics help to predict unmuffled sound pressure level (SPL) spectra that agree reasonably with the experimentally measured spectra.

Experimental investigation on waste heat driven activated carbon-methanol adsorption cooling system

This paper presents design and fabrication of an adsorption refrigeration system working with activated carbon-methanol and coupled to the exhaust system of a multi-cylinder turbo-charged diesel engine. We have also carried out experiments to study the cycle time, refrigeration effect and COP of the cycle. This paper is reported of the original experimental data obtained from experimentation of a real adsorption refrigeration setup. We have studied and reported the effects of minimum bed temperature (T 1) and maximum bed temperature (T 3), the two most important parameters influencing the performance of an adsorption refrigeration system. From experimental result it is observed that the maximum temperature (T 3) of the cycle should be kept as high as possible to generate higher volume of methanol from the activated carbon and, hence, higher refrigeration effect and COP. Since, the temperature of hot water circulated through the desorption bed has been restricted to 90 °C, it takes long time duration to achieve T 3 above 80 °C and hence, during the experiment, the maximum temperature of the bed (T 3) has been limited to 80 °C. It is also observed that the minimum temperature of the bed (i.e., the temperature of the bed after end of adsorption) (T 1) should be kept as low as possible to optimize COP of the cycle. The experimental results show that, for T 1 of 30 °C and T 3 of 80 °C, the maximum refrigeration effect is 1519.41 kJ per cycle for the given configuration of the refrigeration system and the cycle COP is 0.21. Uncertainty analysis predicts that variation of experimental COP varies between ±6.59%. This paper also presents different practical problems that faced by the authors during fabrication of the setup, for the benefit of the future researchers. The study also aims to comment on the capability of meeting the air-conditioning requirement of a vehicle by the waste heat associated with exhaust gases only, without requiring any extra power from the engine, thereby reducing fuel consumption and environment pollution.

Model of exhaust system of a traction diesel engine with pulse supercharging on transient modes

A mathematical model of joint operation of a piston engine with pulse turbine drive, compressor as well as air supply of a diesel locomotive is presented in the article. This model in an integral part of the complex engine-generator power unit of a diesel locomotive in steady states and transient conditions, developed by the authors. The periodic process in the exhaust manifold is represented as two specific characteristic ranges which encompass the process of forced exhaust and the scavenging process. The scavenging calculation is carried out jointly with the processes taking place in the inlet manifold of the engine, including inlet devices of the locomotive. The process of forced exhaust is calculated separately from the inlet processes and doesn`t require usage of empirical coefficients of impulsiveness. Both processes are represented as systems of nonlinear algebraic equations describe in the quasi-steady flow of working fluid in the elements of the inlet and exhaust tracts. The gas-dynamic calculation of the turbine in the transition process is conducted while taking into account changes in flow angles on the rotor blades. As a result of numerical calculation of the a8S22W diesel operational indices in transient modes, a satisfactory compliance of the calculated and the experimental results was obtained.

Diesel Engine Inlet and Exhaust System Fault Detection Based on PSO-BP NN

There is high failure rate in diesel engine inlet and exhaust system, so the inlet and exhaust system condition monitoring and fault diagnosis is of great significance.To overcome drawbacks of pure BP algorithm, a heuristic algorithm is adopted to give a transition from particle swarm search to gradient descending search to set up a Particle Swarm Optimized Back Propagation (PSO-BP) Neutral Network (NN). Then vibration signals have been measured from a diesel cylinder head by simulating two faults:the gas leak and abnormal lash; The diesel engine vibration frequency energy signals after wavelet packet decomposition are taken as the input feature vectors of NN. Finally, we carry out fault detection experiment by the PSO-BP NN model to validate the method. Experiment results show that the PSO-BP NN has more fast convergence speed and higher diagnosis accuracy than BP NN, and it provides a new fault detection method for engine inlet and exhaust system.

Collection efficiency in narrow electrostatic precipitators with a longitudinal or transverse wire electrode

Recently narrow electrostatic precipitators (ESPs) have become a subject of interest because of their possible application in diesel engine exhaust systems. In this work, results of particle collection efficiency measurements in narrow electrostatic precipitators for negative and positive dc voltage polarity are presented. The ESP used in this work was a parallelepiped equipped with wire discharge electrode and two collecting plate-electrodes. The experiments were carried out for two discharge electrode positions: longitudinally or transversely to the main flow direction. The obtained results showed that the collection efficiency strongly depends on the discharge electrode position. It is higher in the ESP with longitudinally-to-flow placed discharge electrode. The collection efficiency is also influenced by the EHD secondary flow generated in the ESP. The EHD secondary flow with high migration velocity (y-component of the particle velocity) and low turbulence intensity increase the chance of the particle deposition on the collecting electrodes.