Exhaust Manifold Research Articles

Experimental study on influence of high exhaust backpressure on diesel engine performance via energy and exergy analysis

Marine diesel engines can be exposed to high backpressure conditions, because various aftertreatment systems and waste heat recovery devices have been widely applied to reduce the emission level, and the outlet of its exhaust manifold is normally below sea level. This article aims to understand the influence of exhaust backpressure on turbocharged engine performance. Diesel engine tests under high backpressure was conducted and it has been found that engine output power drops sharply. To explore the reasons and further study the recovery method, analysis of energy and exergy was carried out. With the increase of backpressure, turbo expansion ratio reduces sharply. But the energy upstream turbine doesn't decrease necessary due to the increase of exhaust temperature. Simultaneously, the exhaust exergy gradually increases by 10.3% when the backpressure increases from 0 bar to 0.55 bar at 75% load, leading to improved energy grade. The turbine output power reduces 56.7% because of the combination results of reduced expansion ratio and increased exhaust energy grade. The method of power recovery should balance these two factors. The study can enlighten the method of power recovery of diesel engine confronted by high backpressure conditions.

Development of A Prototype Extractor of CO₂ from Exhaust Gases

A Prototype Extractor of CO₂ from Exhaust Gases adopting Post-combustion capture process is developed in this study and its performance was evaluated. The system consists of a small petrol engine of 1kw power, an absorber with volume of 0.00054 m³, a balloon that can contain sizeable amount of exhaust gas, a washer of 0.0181m³, a compressor of 1hp, a dryer which consist of two compartment, with internal volume of 0.00093 m³insulated with fibre glass to prevent heat loss. All of these component parts works in a circle, to convert stockpiled exhaust gases from exhaust manifold point source of an electrical power generating set into carbon (iv) oxide (CO2). This system was carefully developed to ensure extraction of pure CO₂ from the waste emission gases. Study was conducted using the developed system to extract suspected CO₂ gaseous substance from exhaust gases. The obtained gaseous substance was assay for chemical analysis test using sodalime solution (CaHNaO2). The result of the test confirmed the extracted gaseous substance as CO₂ gas by changing a colorless sodalime solution to a milk color. It is also found that the quantity of CO₂ gas generated increases with the increment of the quantity of the fuel consumed by the Petrol engine. The produced CO₂ gas can be utilized as commodity in the industrial production of materials and fuels. This work has elucidated one of the means of converting waste emissions (exhaust gases) to wealth and could help to reduce greenhouse effect thus providing a friendly environment for humans’ inhabitants.

Dynamic individual-cylinder analysis of a Gasoline Direct Injection engine emissions for cold crank-start at elevated cranking speed conditions of a Hybrid Electric Vehicle

The cold crank-start phase significantly contributes to the engine-out total emissions during the US Federal Test Procedure (FTP). A Gasoline Direct Injection (GDI) engine dynamics and emissions are investigated during the first three engine cycles of the cold crank-start in Hybrid Electric Vehicle (HEV) elevated cranking speed at 20 °C. To this end, the impact of the operating strategy on the individual-cylinder engine-out emissions is analyzed quantitatively. For this purpose, a new dynamic method was developed to translate the engine-out emissions concentration measured at the exhaust manifold outlet to mass per cycle per cylinder. The HEV elevated cranking speed provides valve timing control, throttling, and increased fuel injection pressure from the first firings. This study concentrates on analyzing the cranking speed, spark timing, valve timing, and fuel injection strategy and parameters effect on engine-out emissions. Design of Experiment (DOE) method is used to create a two-step multi-level fractional-factorial test plan with a minimum number of test points to evaluate the significant parameters affecting engine-out emissions during cold crank-start. Out of the first step DOE analysis, the optimal cranking speed, spark timing, and valve timing, which results in the lowest unburnt HydroCarbon (HC) and NOx emissions, are distinguished. Then, fixing the first step parameters at their optimal values, the second step is accomplished with the fuel injection parameters sweep. The split injection parameters, including the Start of the first Injection (SOI), End of the second injection (EOI), and split ratio (SR), in addition to the first cycle additive fuel factor, are investigated. Results show that the high cranking speed with stabilized low Manifold Absolute Pressure (MAP), highly-retarded spark timing, high valve overlap, late intake first injection, 30 CAD bTDC firing EOI, and low first cycle fuel factor reduces the HC emissions 94%.

Post-oxidation phenomena enhancement with scavenging and secondary air injection in exhaust manifold of a turbocharged GDI engine

A detailed investigation of post-oxidation phenomena by individual and combined effects of scavenging (VVT tuning) and secondary air injection (SAI) was performed. The 1-D simulation including a post-oxidation model developed by Stuttgart University as an international collaboration was used for investigation which includes the main exhaust gas species as CO, H2, and O2-based chemical reactions. Then, experimental validation was conducted on a 4-cylinder turbocharged gasoline direct injection (GDI) engine. From the results, it was noted that the post-oxidation can be actuated at limited operating conditions as higher overlap in moderated speed and load only when scavenging phenomena are considered. However, at lower overlap, it is restricted due to lower O2 scavenging even though the exhaust temperature meets the post-oxidation requirement. Also, the in-homogeneity observed at higher overlap that restricts the significant post-oxidation before the turbocharger upstream. On the other hand, the SAI mechanism can actuate the post-oxidation even at lower overlap if enough O2 concentration, exhaust temperature, and adequate mixing are attained. Hence, the post-oxidation zone can be extended to lower speed-load and overlap if both parameters as scavenging and SAI introduced together. This can possibly lead to better turbo-performance along with lower emissions. However, thermal efficiency needs to be compromised to some extent. It was also found that the effective post-oxidation can be actuated by SAI compared to scavenging-based phenomena if the same concentration of the O2 and temperature are maintained by both mechanisms. This appeared due to the fresh air continuously injected at the exhaust port even at the time of exhaust valve opening duration in SAI mechanism that allows the better mixing of O2 and hot unburned gas species. However, in scavenging-based phenomena, firstly, hot unburned gas passed through the exhaust manifold and then scavenged air follows which restricts mixing between scavenged air and unburned gas species.

Multi-branch junction boundary model of an internal combustion engine intake and exhaust manifold system

Multi-branch junctions are commonly used in highly integrated supercharged internal combustion engines. Accurate prediction of flow performance is critical to engine cycle simulation. However, the few studies on this type of junction boundary model focus on incompressible fluid, which leads to insufficient accuracy in predicting compressible flow. In this study, based on a constant-pressure model commonly used to calculate multi-branch junctions, by considering fluid compressibility, we developed a momentum conservation model and a pressure loss coefficient model, respectively, that are tailored to multi-branch junctions. The momentum conservation model accounts for structural parameters such as branch angle and the influence of Mach number, and hence it improved the prediction accuracy. For a certain type of high-power-density internal combustion engine, the maximum simulation error is reduced from 7.58% to 2.47% in the engine performance prediction at the rated speed after using the momentum conservation model. The proposed pressure loss coefficient model was mainly used to compensate for the shortcomings of the momentum conservation model in the multi-branch calculation efficiency reduction, which is more dependent on the pressure loss coefficient database provided by the experiment. The influence of fluid compressibility was also considered. This investigation can provide tailored tools for multi-branch junction performance prediction in different functional simulation scenes.

APPLICATION OF TORQUE EXPANSION CHAMBER (TEC) AND NOZZLE ON EXHAUST MANIFOLD HONDA SUPRA X 125

Gasoline motorcycles are a means of transportation that is currently the most in-demand by the people of Indonesia. Most of the youth are waiting for gasoline-fueled motorbikes with superior performance so many lovers from the automotive sector, researchers and industry make modifications to improve the performance of these vehicles. This study aims to improve the performance of the gasoline engine. The research method used is to modify the exhaust manifold on the combustion engine. Modifications are made by adding a Torque Expansion Chamber (TEC) 1 tube 2 channels and variations of nozzles 40, 50, and 60. The next step is to test torque, power, and specific fuel consumption. The results show that the use of 1 tube 2 channel TEC and variations of nozzles 40, 50, and 60 can increase torque, increase power and reduce specific fuel consumption. The highest torque of 9.94 Nm was obtained at 5500 rpm using 1 tube 2 channel TEC and 50 nozzle variations. The highest power of 8.03 HP was obtained at 6250 rpm using 1 tube 2 channel TEC and 50 nozzle variations. Minimum specific fuel consumption with a value of 0.14145 kg/kWh was obtained by using TEC 1 tube 2 channel and nozzle variation 40. Increasing torque by using modified TEC 1 tube 2 channel and nozzle variation 40, 50, and 60 is due to back pressure so that heat that comes out with the exhaust gases is not completely removed by the environment. The increase in power is caused because the power is directly proportional to the torque, while the decrease in specific fuel consumption is caused because the specific fuel consumption is inversely proportional to the power.

Effect of deposition of carbon deposits on charge flow in EGR valve in CI engine

The exhaust gas recirculation (EGR) valve regulates the exhaust gas flow between the engine exhaust manifold and the inlet one. This allows the inlet air to warm up, improving fuel evaporation and reducing the combustion temperature of the charge. Such a valve reduces the number of harmful substances in the exhaust gas. The valve sticks when too much sediment builds on the walls of the exhaust system, especially during driving in urban conditions or when leaks in the vacuum or exhaust pipes occur. A faulty valve causes the engine to run unevenly at idle speed and under light loads. The defective EGR valve weakens the inlet manifold capacity, increases combustion, clogging of the particulate filter, damage to the lambda probe. A blocked EGR valve may lead to engine immobilization as a result of the operation of its computerized control system. A model of the EGR valve of a selected diesel engine was developed to determine the velocity distribution of the load flowing in it for different values of the degree of valve opening and the volume of deposits on the valve walls. The volume of accumulated carbon deposits on the walls of the EGR valve was measured using a real engine. Based on the recorded mileage of the vehicle, the assumed average speed of the car, and the driving style of the driver, the intensity of deposition of carbon particles on the walls was estimated.

Design and Fabrication of Exhaust System of Formula Student Car

Abstract— The overall aim of this paper is to refine the design and manufacturing techniques of the exhaust system of FSAE cars. The main objective of this paper is selection of ideal geometry of the 4-cylinder engine (GSX R600) exhaust manifold in terms of optimization of back pressure and reduction in gross weight of the exhaust system. For achieving this, we have considered runner length and diameter, muffler diameter, flow of gases in the exhaust manifold, volumetric efficiency, etc. Softwares used in design and validation are Solid works, Ansys and GT Suite. Keywords— FSAE, Exhaust Runners, Collector, muffler, CFD, 1-D engine simulation, NRC

Microsrtructural and Mechanical Characterization of HVOF-Sprayed Ni-Based Alloy Coating

The various engineering components works under aggressive environments include the furnace parts, sliding parts in lathe machine and exhaust manifolds. Cast iron is used in these applications and important intention of this research work is to study on enhance the useful period of life.HVOF (High Velocity Oxy-fuel) sprayed Alloy-718coatings on cast iron were analysed. Coatings were characterised by field emission scanning electron microscopy (FE-SEM), Optical microscope (OM) and X-ray diffraction for its microstructural analysis. Energy dispersive spectroscopy (EDS) of the bare and coated samples was used to confirm the elemental details of the powder and the coating. Porosity measurements were taken and showed the 1.6% for Alloy-718 coating. Microhardness investigation was conducted for the Alloy-718 coating, and it was resulted as 560±20 HV. The bare material has hardness of 225±10, and there is a substantial difference of hardness found as 2.5 times higher. The fracture toughness was found to be 4.0 MPa.m1/2.

Effects of propeller load fluctuations on performance and emission of a lean-burn natural gas engine at part-load conditions

Providing stable combustion of lean-burn natural gas engines was always a big challenge, particularly during a low load operation. In transient sea conditions, there is an additional concern due to irregular time-varying loads. Therefore, this study aimed at investigating the part-load operation of a marine spark-ignition lean-burn natural gas engine by simulating the entire engine. The engine's essential components are modeled, including air manifold, intake valves, fuel system, controllers, combustion chamber, exhaust valves, exhaust manifold and turbocharger.In steady-state, the results of emission compounds from modeling have been compared to measured data from 25% to 100% loads. For transient conditions, for the sample time of about 50 min, the fuel flow and turbocharger output are selected from the vessel logged data and compared with the simulation results. The model has shown the great potential of predicting the engine response throughout the steady-state and transient conditions. Simulating the engine at part-load transient condition showed that the unburned hydrocarbon formation, known as methane slip in lean-burn gas engines, is more than the part-load steady-state. This increase of methane slip is due to the combustion instability in lower loads and flame extinguishing in such transient conditions. The engine measured data shows a double amount of methane slip in a 25% load than the 100% load in steady-state. However, the simulation output in the transient conditions confirms an increase in methane slip over four times than equivalent steady-state load. Moreover, the lean-burn gas engine releases less NOX in part-load operation in a steady-state due to lower in-cylinder temperature. In transient conditions, there is remarkable instability in excess air ratio. Due to this instability, there is a rich mixture in instantaneous time steps during loads up. Therefore, it will result in an unusually high amount of NOX, and more than two times in comparison with the equivalent steady-state output.

Numerical Study of Exhaust Manifold

Abstract: The Exhaust manifold is an important component which affects the performance of the I.C engine. The exhaust system for any type of vehicle consists of an exhaust manifold, catalytic converter, resonator and a muffler which is connected to a tailpipe. Exhaust gases at the end of exhaust stroke are sent to the exhaust manifold through exhaust valves. The exhaust manifold has to withstand and operate under high exhaust temperature and pressure. The design aspect of the exhaust manifold has to be done through trial and error method to find the optimum layout to extract the performance of the manifold. In this paper, we will analyse the exhaust manifold through conjugate heat transfer. Keywords: Exhaust Manifold, Solidworks, Ansys, Conjugate Heat Transfer

Experimental Investigation on Carbon Dioxide Reduction by Using Post Combustion Carbon Capture System in a Spark-Ignition Engine

Global warming is a serious environmental concern that affects humans, wildlife, and ecosystems. Carbon dioxide reduction is the need of the hour as it a major constituent of global warming. The quantum of carbon dioxide released in the exhaust depends on the number of carbon atoms present in the fuel used. The present study investigates the reduction of engine out carbon dioxide emission. For carbon dioxide reduction post combustion capture sys- tem is used. In post combustion capture system carbon dioxide is absorbed by using absorption catalyst. In this capture system, carbon dioxide is absorbed after the combustion. Among various absorption catalyst, monoethanolamine (MEA) is used, as it can react more quickly with carbon dioxide than other absorbents. Monoethanolamine is continuously injected in the exhaust mani- fold. Empty chamber is added in the exhaust manifold for increasing the resi- dent time of the reaction of amine with carbon dioxide. MEA reacts with carbon dioxide forms ammonium carbamate. Carbamate is approved by the Environ- mental Protection Agency as an inert ingredient, used for insect and rodent control in areas where agricultural products are stored.

An Overview and Thermal Analysis of Vehicle Exhaust Gasket

The Exhaust system is an integral part of the vehicle. To remove the waste gases from the vehicle it came in existence. The performance of engine is mainly affected by exhaust manifold and gasket used because they directly affect the engine stability and control. Generation of back pressure and thermal load restrict to achieve desirable requirement. The protection of the exhaust system from internal and external factors it is necessary to optimize the design of exhaust manifold and gasket because development of crack is more in these two parts. A gasket is designed in this project. For 3D modeling of gasket Creo 4.0 is used and with the help of ANSYS 17.1 the analysis has performed. Keywords: Design, Thermal analysis, Gasket, Creo, ANSYS Analysis.

Hot Oxidation Resistance of a Novel Cast Iron Modified by Nb and Al Addition for Exhaust Manifold Applications

Hot Oxidation Resistance of a Novel Cast Iron Modified by Nb and Al Addition for Exhaust Manifold Applications

Vibration analysis of composite exhaust manifold for diesel engine using CFD

Researchers used computer-aided design and computational fluid dynamics methodologies to establish the flow simulation process and find the critical level temperatures. CATIA V5 R20 has been used to create the geometric model. As a result, the normal study state conditions are performed at varied coefficient levels in all boundary areas. Three solid dimensioning approaches were used in the simulation process. The internal flow structures and velocity contours were obtained using computational fluid dynamics flow software. As a result, the structural elements in the exhaust manifold were mapped from a minimum range of 0.2933 to a maximum range of 0.99995 under various thermal conditions. The gradient temperature and velocity contour findings were absorbed in a flow process with maximum energy transmit of 0.2917 m/s and a temperature of 350 °C calculated using Computational fluid dynamics (CFD) techniques. The simulated data found the failure areas at the bottom of the exhaust manifold. At 0.005% of the input conditions, the stress concentrations were detected. Computational fluid dynamics simulation techniques reduced stress concentration levels by 14%.

CFD Topology and Shape Optimization of Twin Ports in Integrated Exhaust Manifolds

<div class="section abstract"><div class="htmlview paragraph">The optimization of the exhaust port shape for best mass flow is an excellent opportunity to improve fuel economy, emissions, and knock sensitivity of internal combustion engines (ICE). This is valid for many different types of combustion systems including gasoline, alcohols, alternative fuels such as compressed natural gas (CNG) or hydrogen, and e-fuels. Nowadays, so-called cylinder-head integrated exhaust manifolds (IEM) guide the exhaust gas from the combustion chamber to the turbocharger. This specific design requires lots of strong bends and turnings of the exhaust ports in very narrow space, since they need to be guided through a labyrinth of bolts, water cores, and oil passages. In fact, this challenges the avoidance of increased pressure drops, reduced mass flow rates, and deterioration of port flow efficiencies. The optimization of the individual port by computational fluid dynamics (CFD) is a proper means to minimize or even eliminate these drawbacks. Meanwhile, there are several powerful optimization methods for three-dimensional flows on the market. In this paper, a combined strategy of CFD topology and shape optimization is presented. This method has been applied to several Ford four-valve engine designs with either twin (Siamese) exhaust ports as well as single ports within two separate IEMs. CFD optimizations have been done for various valve lifts resulting in improved mass flow rates by up to 14 % and an improved mass flow balance between the twin exhaust ports. New flow cross-sections such as L-, F-, and T-shapes have been identified. At the end, an initial design of flow-optimized ports has been generated including body-fitted water jacket surfaces. This allows the designer to already start with an optimized exhaust port design. The new workflow is highly efficient, reduces development time, improves result quality, and may reduce the number of expensive prototypes as well as time-consuming test-rig measurements.</div></div>

Analysis on capability of power recovery of marine diesel engine at high backpressure conditions

Marine diesel engines can be exposed to high backpressure conditions in the scenario of maritime, because the outlet of its exhaust manifold is normally below the sea surface to reduce the emission level. The performance of the engine has been confirmed to drastically deteriorate due to the high exhaust backpressure. The current methods for turbo-engine matching and power recovery at high backpressure conditions are specific instead of general. This article aims to understand the mechanism of influence on turbocharged engine performance by exhaust backpressure, and to develop a performance evaluation method as well as optimized methods of turbo-engine matching at high backpressure conditions. Firstly, numerical method is established for a 16-cylinder V-type turbocharged diesel engine and calibrated/validated based on experimental results. The influence of the backpressure on engine and turbocharger performance is discussed by the numerical method. The power recovery efforts are founded to be constrained by the maximum cylinder pressure and exhaust temperature. The influence of the effective flow area of the turbine and turbocharger efficiency on the operational constraints are discussed. It is concluded that the influence on intake air mass flow and fuel margin is the source of the influence on the constraints. Based on the findings, a capability region of engine power recovery is proposed, which is bounded by curves of maximum cylinder pressure and maximum exhaust temperature, respectively. Furthermore, the availability of exhaust gas is the root of influencing the boundaries of the region. According to the mechanism, a universal evaluation method based on the available energy of the exhaust gas is proposed which is tailored for turbo-engine matching at different exhaust backpressures.

Marine diesel exhaust manifold failure and life prediction under high-temperature vibration

The working environment of the diesel exhaust manifold is harsh. On one hand, exhaust gas with high temperature continues to flush on the inner wall of the manifold, and on the other hand, the manifold is also affected by some complex factors, such as diesel engine vibration. If the design is unreasonable, air leakage, cracking, and other failure phenomena are easy to appear. In this article, aiming at the aforementioned problems in the exhaust manifold design process, a high-speed diesel exhaust manifold is taken as an example and analyzed by computational fluid dynamics and finite element method technology. The temperature field distribution of the exhaust manifold is simulated by the fluid–structure interaction method, and then the thermal stress distribution is simulated based on the temperature field of the exhaust manifold. According to the thermal stress of the exhaust manifold and the vibration stress in three directions (axial, transverse, and vertical), combined with the time domain acceleration signals, the high-cycle fatigue life of the exhaust manifold is obtained. The exhaust manifold structure is optimized based on the minimum high-cycle fatigue life position. Then, the high-cycle fatigue life analysis of the optimized structure shows that the optimized structure can significantly improve the life of the exhaust manifold. Then, the optimized structure is further analyzed for low-cycle fatigue life to check whether it meets the requirements of low-cycle fatigue life. After simulation, it can be known that the low-cycle fatigue life meets the design requirements. Finally, sensitivity analysis of the fatigue life under different loading conditions (thermal load and vibration intensity) shows that the thermal load has a significant influence on the fatigue life, so the thermal load should be paid attention to in the design process.

Control of High-Temperature Static and Transient Thermomechanical Behavior of SiMo Ductile Iron by Al Alloying

Silicon and molybdenum (SiMo) ductile iron is commonly used for exhaust manifolds because these components experience thermal cycling in oxidizing environment, which requires resistance to fatigue during transient thermomechanical loads. Previous studies have demonstrated that alloying elements, such as Al, to SiMo ductile iron reduces the amount of surface degradation during static high-temperature exposure. However, deterioration of sphericity of the graphite nodules and a decrease in ductility could affect the tendency of cracking during thermal cycling. In this article, the effect of Al alloying on static and transient thermomechanical behavior of SiMo ductile iron was investigated to optimize the amount of Al alloying. A thermodynamic approach was used to confirm the effect of the Al alloying on the phase transformations in two SiMo cast irons, alloyed by 1.8% Al and 3% Al. These two alloys were cast in a laboratory along with the baseline SiMo ductile iron. Several experimental methods were used to evaluate the dimensional stability, physical properties, static oxidation, and failure resistance during constrained thermal cycling testing to compare their high-temperature capability. Experimental results verified that Al alloying increases the temperature range and decreases volume change during eutectoid transformation, which together with enhancement of oxidation protection improved the dimensional stability. Thermocycling tests showed that the number of cycles to failure depends on the amount of Al alloying and the applied high-temperature exposure during each cycle. SEM/EDX, high-resolution TEM and µCT analysis were used to verify the mechanism resulting from the Al alloying protection. It was shown that an optimal level of Al alloying for balancing oxidation and thermal cracking resistance depends on thermomechanical conditions of application.

Efek Penambahan Butanol Terhadap Emisi dan Temperatur Gas Buang Mesin Bensin EFI Menggunakan EGR

The high octane number and oxygen content of butanol can improve combustion more completely and the residual gas resulting from engine combustion is more environmentally friendly. This study examines the effect of adding 5% to 15% butanol at 5% intervals on a gasoline engine with an EGR system with premium fuel on emissions and exhaust gas temperatures. The exhaust gas analyzer was used to measure the combustion gases. Exhaust gas temperature was measured using a thermocouple mounted on the exhaust manifold. The mixture of P85B15 reduced CO levels by 68.11% and HC by 37.50% compared to P100. However, CO2 emissions and exhaust gas temperatures increased. The use of hot and cold EGR generally increased engine exhaust emissions. However, the exhaust gas temperature decreased by 4.72% when the engine used cold EGR and 1.33% when the engine used hot EGR.