Browse Topic: Exhaust manifolds

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A computational approach to Fretting Wear prediction of Steel Gaskets under Thermo-Mechanical load using Archards wear model2024-26-027301/16/2024
IC Engine is the heart of an automobile. The failure in any component of the engine will directly affect the performance of the vehicle. The gaskets are among the many vital parts of an IC engine that are essential in ensuring appropriate sealing to prevent gas and liquid leakage and maintain optimal engine efficiency. Engines use a variety of gasket types to accommodate various sealing requirements. Among them the exhaust manifold gaskets is one of the critical gasket elements in IC engines which seals between Cylinder head and extremely hot Exhaust Manifold, this prevents the leakage of hot exhaust gasses produced during combustion. The gaskets are crucial components because they endure extremely high mechanical loads from the exhaust manifold sliding and banana-shaped bending brought on by thermal expansion, as well as extremely high thermal loads from the high exhaust gas temperatures, which are around 1000°C. These gaskets are additionally subjected to extremely high bolt loads
Reddy, Rajavardhan, Kulkarni, Sanjeev, R B, Govind, Mueller, Frank Oliver
Performance Optimization of an Exhaust System for 4 Cylinder Engine by Implementation of Computational Fluid Dynamics, Acoustic and Thermal Analysis2022-01-076503/29/2022
The engine system requirements have changed from being focused only on delivering engine power to now having to meet environmental emission standards. The exhaust system collects exhaust gases from the combustion cylinders, eliminates dangerous pollutants, decreases noise, and discharges the purified exhaust gases at a safe distance from the vehicle's occupants. Designs of lightweight models for exhausts were always aimed at using newer lighter materials. As the design of an exhaust is more or less fixed, this approach is hardly profitable anymore. The most important components of an exhaust system are the exhaust manifold, the catalytic converter, the muffler, the resonator and connecting all of them together are connecting exhaust pipes. In this paper, the optimization of the various elements of 4 cylinder 1.8L engine exhaust system is carried out with the help of analysis software ANSYS 19.2 workbench, by performing ‘Steady State Thermal Analysis’, ‘Acoustic Analysis’ and simulating
Aiyan, Mohammed, Sagar, S Sumanth, Raghav S, Sanjay
Idle sound quality enhancement with optimizing exhaust manifold structure on a H8 engine2022-01-073703/29/2022
Idle sound quality for motorcycle is critical to engineers to achieve. People would like to have a strong individualized sound in idle, but linear and smooth sound in driving condition. Since the idle fluctuation noise is based on the engine firing order, the exhaust manifold structure and the idle frequency by cylinder numbers, thus, compared to the two or three cylinders engines, eight or six cylinders engine are really hard to get a fluctuated tailpipe sound since the its higher firing frequency. However, the surrogate methodology can be applied on these engines. Based on the noise cancellation process in phase and amplitude in the exhaust manifold tube, engineers can manipulate the noise with several lower peaks compare to other higher peaks. In this scenario, people can feel the noise with big fluctuations although the smaller noise peaks are still there but in the masking. In this paper, a special case is presented by this methodology. In that case, an eight cylinders horizontal
Tan, Yang
Performance Optimisation of an Exhaust System for 4 Cylinder Engine by Implementation of Computational Fluid Dynamics, Acoustic and Thermal Analysis2022-01-067703/29/2022
The engine system requirements have changed from being focused only on delivering engine power to now having to meet environmental emission standards. The exhaust system collects exhaust gases from the combustion cylinders, eliminates dangerous pollutants, decreases noise, and discharges the purified exhaust gases at a safe distance from the vehicle's occupants. Designs of lightweight models for exhausts were always aimed at using newer lighter materials. As the design of an exhaust is more or less fixed, this approach is hardly profitable anymore. The most important components of an exhaust system are the exhaust manifold, the catalytic converter, the muffler, the resonator and connecting all of them together are connecting exhaust pipes. In this paper, the optimization of the various elements of 4 cylinder 1.8L engine exhaust system is carried out with the help of analysis software ANSYS 19.2 workbench, by performing ‘Steady State Thermal Analysis’, ‘Acoustic Analysis’ and simulating
Aiyan, Mohammed, Raghav S, Sanjay, Sagar, S Sumanth
Thermal Calibration of Exhaust Manifold FEA Model to Enhance TMF Life Prediction2021-28-012709/15/2021
Exhaust manifold Thermo-mechanical Fatigue (TMF) assessment using Finite Element Analysis (FEA) is complex and the results are sensitive to predicted metal temperatures on manifold. Hence it is recommended to calibrate thermal FEA model with actual test data for accurate prediction of TMF life. This helps to design reliable products. Typically, TMF life of exhaust manifold is validated using transient thermal cycle. Due to few assumptions made in simulation approach, it is observed that the difference between experimental and FEA temperature could be significant. In current approach, exhaust manifold temperature at different manifold locations are calibrated with the measured thermocouple data by varying heat transfer coefficient (HTC) at outer and inner surface of manifold. This approach is capable to provide good correlation at peak temperature and minimum temperature during the thermal cycle. However, there is no degree of freedom to calibrate transient thermal response in between
Patil, Pavan Prakash, SYRIAC, ALEX SHERJY, Kulkarni, Girish Jaiprakash
Investigation and 1D Modelling Approach on Scavenging Air Post-Oxidation inside the Exhaust Manifold of a DISI Engine2021-01-059904/06/2021
The introduction of real driving emission measurements increases the need of improved transient engine behavior while keeping the emissions to a minimum. A possible way of enhancing the transient engine behavior is the targeted usage of scavenging. Scavenging is realized by an inlet- and exhaust-valve overlap. Fresh scavenging air flows directly from intake manifold through the cylinder into the exhaust manifold. Therefore, the mass flow at the turbine increases and causes a reduced turbo lag, which results in a more dynamic engine behavior. The unburned oxygen causes a decrease of the three-way catalyst (TWC) conversion rate. To keep the TWC operation close to stoichiometry, a rich combustion is performed. The rich combustion products (most notably carbon monoxide) mix in the exhaust manifold and react with oxygen so that the conversion rate of the TWC is ensured. In order to investigate the potential and risks of this engine operating strategy, a reliable 1D engine model is necessary
Przewlocki, Jan, Tromellini, Rodolfo, Grill, Michael, Chiodi, Marco, Bargende, Michael
Investigation of H2 Formation Characterization and its Contribution to Post- Oxidation Phenomenon in a Turbocharged DISI Engine2020-01-218809/15/2020
In this research, simulation and experimental investigation of H2 emission formation and its influence during the post-oxidation phenomenon were conducted on a turbo-charged spark ignition engine. During the post-oxidation phenomenon phase, rich air-fuel ratio (A/F) is used inside the cylinder. This rich excursion gives rise to the production of H2 emission by various reactions inside the cylinder. It is expected that the generation of this H2 emission can play a key role in the actuation of the post-oxidation and its reaction rate if enough temperature and mixing strength are attained. It is predicted that when rich combustion inside the cylinder will take place, more carbon monoxide (CO)/ Total Hydro Carbon (THC)/ Hydrogen (H2) contents will arrive in the exhaust manifold. This H2 content facilitates in the production of OH radical which contributes to the post-oxidation reaction and in-turn can aid towards increasing the enthalpy. Through simulations, it was also investigated that
KUMAR, Madan, Moeeni, Salaar, Kuboyama, Tatsuya, Moriyoshi, Yasuo, Przewlocki, Jan, Tromellini, Rodolfo, Grill, Michael, Chiodi, Marco, Bargende, Michael
Numerical Study of the Maximum Impact on Engine Efficiency When Insulating the Engine Exhaust Manifold and Ports During Steady and Transient Conditions2020-37-000206/23/2020
In the present work, a study about the impact on engine performance, fuel consumption and turbine inlet and outlet temperatures adding thermal insulation to the exhaust ports, manifold and pipes before the turbocharger of a 1.6L Diesel engine is presented. First, a 0D/1D model of the engine was developed and thoroughly validated by means of an extensive testing campaign. The validation was performed by means of steady state or transient running conditions and in two different room temperatures: 20ºC and -7ºC d. Once the validation was complete, in order to quantify the significance of adding thermal isolations, the simulations were performed setting the exhaust air path before the turbine as adiabatic. This is evaluated the maximum gain of the technology. Results showed that the thermal insulation proved to have a great potential in regard to T4 increase since this would reduce the warm up time of the aftertreatment systems. However, its impact on engine efficiency was limited in both
Broatch, Alberto, Olmeda, Pablo, Martin, Jaime, Dreif, Amin
Multiple 3D-DIC Systems for Measuring the Displacements and Strains of an Engine Exhaust Manifold2020-01-054004/14/2020
In this study, a unique multi-camera three-dimensional digital image correlation (3D-DIC) system was designed and applied to an engine dynamometer cell to measure the displacement and strain of the exhaust manifold while an engine was running in a durability test. In the engine dynamometer cell, the ambient temperature varies from 25°C to 80°C~100°C cyclically and the exhaust manifold experiences high temperatures up to 900°C with high frequency vibrations. In order to obtain reliable data under such conditions, two 3D-DIC systems were designed and set up in the engine dynamometer. One is a high-speed 3D-DIC system, consisting of cameras with a sampling rate of 1250 frames per second. It was used to measure the local displacement of the bolted joint in the exhaust manifold. The high-speed measurement system is able to record the behavior of the bolt during the thermal cycles. The other system is a high-resolution 3D-DIC system, consisting of two cameras with a resolution of five-mega
Zhang, Wensheng, Li, Junrui, Yang, Lianxiang, Barber, Gary, Chen, Jim, Iqbal, Owais, Singh, Kanwerdip
Towards Quantitative Prediction of Urea Thermo-Hydrolysis and Deposits Formation in Exhaust Selective Catalytic Reduction (SCR) Systems2019-01-099204/02/2019
In order to assist in fast design cycle of Diesel engines selective catalytic reduction (SCR) exhaust systems, significant endeavor is currently being made to improve numerical simulation accuracy of urea thermo-hydrolysis. In this article, the achievements of a recently developed urea semi-detailed decomposition chemical scheme are assessed using three available databases from the literature. First, evaporation and thermo-hydrolysis of urea-water solution (UWS) single-droplets hanged on a thin thermocouple ring (127 μm) as well as on a thick quartz (275 μm), have been simulated at ambient temperature conditions ranging from 473K to 773K. It has been shown that the numerical results, in terms of evaporation rate and urea gasification, as well as droplet temperature history are very close to the experiments if the heat flux coming from the droplet support is properly accounted for. Indeed, an additional conduction flux has proved to be necessary in the evaporation model in order to
Habchi, Chaouki, Quan, Shaoping, Drennan, Scott, Bohbot, Julien
FSI - MRF Coupling Approach For Faster Turbocharger 3D Simulation2019-01-000701/15/2019
Fluid-Structure Interaction (FSI) simulation approach can be used to simulate a turbocharger. However, this predictive 3D simulation encounters the challenge of a long computational time. The impeller speed can be above 100,000 rpm, and generally a CFD solver limits the maximum movement of the impeller surface per time step. The maximum movement must be a fraction (~0.3) of the cell length, thus the time step will be very small. A Multiple Reference Frame (MRF) approach can reduce computational time by eliminating the need to regenerate the mesh at each time-step to accommodate the moving geometry. A static local reference zone encompassing the impeller is created and the impact of the impeller movement is modeled via a momentum source. However, the MRF approach is not a predictive simulation because the impeller speed must be given by the User. A new simulation approach was introduced that coupled the FSI and MRF approach. Like in the FSI approach, the total moment of the impeller was
Abidin, Zainal, Morris, Andrew, Miwa, Jason, Sadique, Jasim, Wang, Yunliang
Achieving Ultra-Low Oil Consumption in Opposed Piston Two-Stroke Engines2019-01-006801/15/2019
The opposed piston two-stroke (OP2S) engine architecture is widely recognized for its improved fuel efficiency relative to a four-stroke engine. Achates Power Inc. seeks to demonstrate the market readiness of the OP2S engine by proving competitive in other important areas, one of which is oil consumption. Achieving oil consumption competitive to modern four-stroke engines is thus a key step in bringing OP2S technology to market. Two-stroke engines have historically suffered from higher engine lube oil consumption and subsequent emissions and durability challenges. This is primarily due to two main features of traditional two-stroke engines; the direct interaction of the piston skirt and rings with the intake and/or exhaust ports, which results in a direct leak path for lube oil to the combustion chamber and/or exhaust manifold, and crankcase-scavenged architectures which entrain oil into air being pumped through the crankcase. The OP2S engine architecture directly addresses these
Chown, Dan, Koszewnik, John, MacKenzie, Ryan, Pfeifer, Dan, Callahan, Brian, Vittal, Manny, Froelund, Kent
Optimization of EGR Mixer to Minimize Thermal Hot Spot on Plastic Duct & Soot Deposition on Throttle Valve Using CFD Simulation2019-26-028601/09/2019
In recent time, with inception of BS VI emission regulation with more focus on fuel economy and emission, many engine parts which were conventionally made from metal are getting replaced with plastic components for reducing weight to attain better fuel economy. EGR is commonly used technique to reduce emissions in diesel engine along with after treatment devices. EGR reduces peak combustion temperature inside the combustion chamber thereby reducing NOx. EGR is bypassed from the exhaust manifold, cooled down in EGR cooler and mixed with intake air at upstream of the intake manifold. Throttle valve is used for controlling the charged air flow to cylinders for different vehicle operating conditions. With compact engine layout EGR mixer are often located near to throttle valve thereby increasing the possibility of soot deposition on throttle valve. Once these soot & hydrocarbons cool down they can transform into sticky amorphous carbon, which obstruct the functioning of throttle valve
Agrawal, Ayush, Raju, Kumar, Santra, Tanmay, Gopinathan, Nagarajan, Varghese, Joy, Ghadei, Sataya Brata
Study of a Turbocharged Engine for Motorbike Application2018-32-007910/30/2018
Nowadays, the engine charging practice is widely adopted in the automotive field in relation to the “downsizing” technology: the reduction of the displacement and the adoption of a higher boost pressure, through a charging system, allow shifting the engine operating point in a zone of higher efficiency for a given engine torque. On the other hand, given a certain displacement, a supercharger can be adopted to increase the performance of the engine. The objective of this work is to provide a detailed analysis about the feasibility of the implementation of a charged engine to a motorbike, with main focus on the possibility to achieve a challenging performance target: in a first stage, several engine architectures (In-line, V-configuration, Boxer) together with different charging concepts (centrifugal or volumetric compressor, with mechanical or fluid-dynamic connection to the engine) have been analyzed from the point of view of packaging. In a second part, a V4 engine architecture has
Bevilacqua, Vincenzo, Corvaglia, Giovanni, Fuoss, Klaus, Penzel, Matthias
Preparing BMW Motorrad’s Boxer Engine for the Future: Improving Performance, Driveability and Efficiency While Fulfilling Future Emission Standards2018-32-008310/30/2018
Engine development mostly revolves around the same competing goals. With the implementation of the EU4 and EU5 emission standards for motorcycles, the difficulty of increasing performance and improving driveability and efficiency, while simultaneously fulfilling the Emission standards becomes even higher. Though the automotive industry offers a variety of solutions for the named topics, their implementation in a high performance motorcycle engine with specific needs regarding packaging, a wide operating range and full load behavior, represents a special challenge. This paper presents the approach of BMW Motorrad to meet these goals on the example of the boxer engine, focusing on the methodology throughout the development process. The gas exchange system of the engine was optimized using 1D gas dynamic simulations and 3D CFD analysis for a redesign of the valve train, ports and valves. The results of the calculations were further confirmed by experiments at the flow test bench measuring
Oppelt, Maximilian, Schwarz, Frank, Eibl, Rüdiger, Gaitan, Pedro
Sodium Cooling Efficiency in Hollow Valves for Heavy Duty Engines2018-01-036804/03/2018
As a consequence of the ongoing evolution of engines, where performance is continuously improving and the use of alternative fuels is being adopted by many engine manufacturers, thermal working conditions of the exhaust valves are increasingly critical. In order to better resist the higher temperature levels of the exhaust gases, current development ranges from improvement of the cooling concept for the overall system, new materials for valve set components up to the upgrade of the exhaust manifold material. Change in the design of several valvetrain components due to the increased thermal loads is a logical consequence of this technical evolution process. Hollow exhaust valves filled with Sodium (Na) are a known technology that is widely used in passenger car engines to improve thermal behavior and to avoid the need to change to expensive materials (Ni-base alloys). Nevertheless, shaker-cooling effect of Na for engine speeds below 3.000 [rpm] has been questioned in the past and this
Zenklusen, Fernando, Coenca, Marcio, Puck, Alexander
A Simulative Study for Post Oxidation During Scavenging on Turbo Charged SI Engines2018-01-085304/03/2018
Fulfilling exhaust emissions regulations and meet customer performance needs mainly drive the current engine development. Turbocharging system plays a key role for that. Currently turbocharging should provide highest engine power density at high engine speed by also allowing a very responsive performance at low end. This represents a trade-off in turbocharger development. A large scaled turbine allows having moderate exhaust gas back pressure for peak power region, but leading to loss of torque in low engine speed. In the last years of engine development scavenging helped to get away a bit from this trade-off as it increases the turbine mass flow and also reduces cylinder internal residual gas at low engine speed. The mostly in-use lean strategy runs air fuel ratios of closed to stoichiometric mixture in cylinder and global (pre catalyst) of λ = 1.05 to l = 1.3. This will be out of the narrow air fuel ratio band of λ = 1 to ensure NOx conversion in the 3-way-catalyst. The use of the
Guenther, Torsten, Grill, Michael, Bargende, Michael
Simulation Study of 1D-3D Coupling for Different Exhaust Manifold Geometry on a Turbocharged Gasoline Engine2018-01-018204/03/2018
One-dimensional (1D) simulation tools, the computing speed of which is relatively fast, usually solve simple complexity problems. The solving process of 1D simulation is mostly based on one-dimensional dynamic equations and empirical laws and thus in some cases it cannot obtain a similar accuracy with the time-consuming three-dimensional (3D) simulation tools. The 1D-3D co-simulation, which combines the advantages of the two simulation tools while minimizes the disadvantages, is a method that integrates and runs the two simulation tools concurrently. The coupled simulation can offer a 3D analysis for which a detailed information is needed while offer system level information in the rest of the whole system where averaged results are sufficient. The approach not only minimizes the computational cost, but avoids demand for imposing accurate boundary conditions to the 3D simulation. But nowadays, a lot of paper only use the approach to obtain boundary condition from 1D environment, few
Zhang, Chaolin, Hu, Bo, lai, Chenguang, Zhang, Hailin, Qin, Ling, Leng, Xiaoli, Huang, Wenpeng
Pressure Amplitude Influence on Pulsating Exhaust Flow Energy Utilization2018-01-097204/03/2018
A turbocharged Diesel engine for heavy-duty on-road vehicle applications employs a compact exhaust manifold to satisfy transient torque and packaging requirements. The small exhaust manifold volume increases the unsteadiness of the flow to the turbine. The turbine therefore operates over a wider flow range, which is not optimal as radial turbines have narrow peak efficiency zone. This lower efficiency is compensated to some extent by the higher energy content of the unsteady exhaust flow compared to steady flow conditions. This paper experimentally investigates the relationship between exhaust energy utilization and available energy at the turbine inlet at different degrees of unsteady flow. A special exhaust manifold has been constructed which enables the internal volume of the manifold to be increased. The larger volume reduces the exhaust pulse amplitude and brings the operating condition for the turbine closer to steady-flow. The operating points are defined by engine speed and
Holmberg, Ted, Cronhjort, Andreas, Stenlaas, Ola
High-Performance Rear- and Mid-Engine Vehicle Exhaust System Temperatures2018-01-143604/03/2018
Hot surface ignition of combustible material is a known cause of vehicle fires. Although the detailed mechanisms of hot surface ignition are highly complex, the surface temperature is known to play a crucial role in this process. There has been limited previous work in the literature on this topic, much of which has focused on engine or exhaust system surface temperatures of the most common types of passenger vehicles. Also, much of this work was done in an unrepeatable manner and suffered from measurement technique induced errors. The focus of the present work is on repeatable and low measurement technique induced error temperature measurements of exhaust system surface temperatures of rear- and mid-engine sports cars. Temperature measurements were made at several points along the exhaust systems of vehicles both with and without turbo chargers on a 5-mile oval track. The exhaust system surface temperatures were examined under conditions of transient acceleration and steady-state
Papageorge, Michael, Colwell, Jeff
Thermo-Mechanical Fatigue Testing of Welded Tubes for Exhaust Applications2018-01-009004/03/2018
Selected ferritic stainless steel sheets for exhaust applications were tested under thermo-mechanical fatigue (TMF) condition in the temperature range of 400-800 °C with partial constraint. Straight welded tubes were used as the testing coupons to withstand large compression without buckling, and to understand the effect of welding as well. Repeated tests confirmed the observed failure scenario for each material type. The hysteresis loop behaviors were also simulated using the mechanism-based integrated creep and fatigue theory (ICFT) model. Although more development work is needed, for quick material screening purpose this type of testing could be a very cost effective solution for materials and tube weld development for exhaust applications.
Quan, Guangchun, Wu, Xijia, Lafleur, Luc, zhang, Zhong
The NiceC Programming LanguageTBMG-2831502/01/2018
NiceC is an improved version of ANSI C. It attempts to clean up C as much as possible using syntax translation. A type checker for NiceC is under development. The NiceC programming language is translated to, and fully compatible with, ordinary C. Thus it can be used as a drop-in replacement for C. The main benefits of using NiceC are as follows:
Experimental Investigation of Cold Start Emission using Dynamic Catalytic Converter with Pre-Catalyst and Hot Air Injector on a Multi Cylinder Spark Ignition Engine2017-01-236710/08/2017
Control of harmful emissions during cold start of the engine has become a challenging task over the years due to the ever increasing stringent emission norms. Positioning the catalytic converter closer to the exhaust manifold is an efficient way of achieving rapid light-off temperature. On the other hand, the resulting higher thermal loading under high-load engine operation may substantially cause thermal degradation and accelerate catalyst ageing. The objective of the present work is to reduce the light-off time of the catalyst and at the same time reduce the thermal degradation and ageing of the catalyst to the minimum possible extent by adopting an approach with Dynamic Catalytic Converter System (DCCS). The emission tests were conducted at the cold start of a 4 cylinder spark ignition engine with DCCS at different positions of the catalyst at no load conditions. Also emission tests were conducted with pre-catalysts of 20% volume and 40% volume of the main catalytic converter and
Mahadevan, Ganesan, Subramanian, Sendilvelan
Simulation and Test Research for Integrated Exhaust Manifold and Hot End Durability2017-01-243210/08/2017
In order to reduce emissions, size and manufacturing cost, integrated exhaust manifold become popular in gasoline engine, especially in three-cylinder engine. Moreover, due to shorter length, lighter weight, and less component connections, the exhaust manifold and hot end durability will improve apparently. In this work, an advanced cylinder head with integrated exhaust manifold is adopted in a three-cylinder turbo engine. Because of this integration characteristic, the gas retain in cylinder head longer and the temperature reach higher level than normal cylinder head, which will cause thermal fatigue failure more easily. To validate the exhaust manifold and hot end durability, series simulation and test validation work have been done. Firstly, overall steady state and transient temperature simulation was done for global model. For turbocharger, in order to simulate the outlet turbulent flow and 3d rotation, a code was compiled to define this 3d rotation. In this code, the inlet
Li, Xiangwang, Wang, Weimin, Zou, Xiongcai, Zhang, Zhiming, Zhang, Wenlong, Zhang, Shemin, Chen, Tao, Cao, Yuhuang, Chen, Yuanda
Scavenge Ports Ooptimization of a 2-Stroke Opposed Piston Diesel Engine2017-24-016709/04/2017
This work reports a CFD study on a 2-stroke (2-S) opposed piston high speed direct injection (HSDI) Diesel engine. The engine main features (bore, stroke, port timings, et cetera) are defined in a previous stage of the project, while the current analysis is focused on the assembly made up of scavenge ports, manifold and cylinder. The first step of the study consists in the construction of a parametric mesh on a simplified geometry. Two geometric parameters and three different operating conditions are considered. A CFD-3D simulation by using a customized version of the KIVA-4 code is performed on a set of 243 different cases, sweeping all the most interesting combinations of geometric parameters and operating conditions. The post-processing of this huge amount of data allow us to define the most effective geometric configuration, named baseline. In the second step of the study, the baseline is further optimized, keeping into account some fundamental design constraints, such as the
Mattarelli, Enrico, Rinaldini, Carlo, Savioli, Tommaso, Cantore, Giuseppe, Warey, Alok, Potter, Michael, Gopalakrishnan, Venkatesh, Balestrino, Sandro
Efficiency Improvement by Separation of Vapor and Liquid in Condenser Headers2017-01-018003/28/2017
This paper introduces the concept of separation of two-phase flow in condenser as a way to improve condenser efficiency. The benefits of vapor-liquid refrigerant separation and the reason why it will improve the condenser performance are explained. Numerical studies are presented on the effects of separation on performance of an R134a microchannel condenser, with the comparison to experiment data. Model predicts that at the same mass flow rate, the exit temperature is lower by 2.2 K in the separation condenser compared with that in the baseline. Up to 9% more flow rate of condensate is also predicted by the model in the separation condenser. Experiment results confirm the same trend. In addition, the reason why a certain circuiting of passes with pre-assumed separation results in the header improves the condenser is investigated by the model and results are presented.
Li, Jun, Hrnjak, Pega
Modelling and Control of Engine Torque for Short-Circuit Flow and EGR Evacuation2017-01-060603/28/2017
Low-Pressure Exhaust Gas Recirculation (LP-EGR) has been shown to be an effective means of improving fuel economy and suppressing knock in downsized, boosted, spark ignition engines. LP-EGR is particularly beneficial at low-speed, high-load conditions, but can lead to combustion instability at lower loads. The transport delays inherent in LP-EGR systems slow the reduction of intake manifold EGR concentrations during tip-out events, which may lead to excessive EGR concentrations at low load. This paper explores leveraging Variable Valve Timing (VVT) as a means of improving the rate of reduction of intake manifold EGR concentration prior to tip-out. At higher boost levels, high valve overlap may result in intake manifold gas passing directly to the exhaust manifold. This short-circuiting behaviour could potentially improve EGR evacuation rates. However, introducing short-circuit flow may lead to lean exhaust flow through the catalyst, and/or necessitate rich in-cylinder conditions that
Wiese, Ashley, Stefanopoulou, Anna, Buckland, Julia, Karnik, Amey Y.
CFD Topology and Shape Optimization for Port Development of Integrated Exhaust Manifolds2017-01-133903/28/2017
Modern cylinder-head designs for gasoline engines are guiding the exhaust gas to the turbocharger system via an integrated exhaust manifold (IEM) which has several advantages like weight and cost reduction. On the other hand, the exhaust ports are running through a package labyrinth and are heavily bent within smallest space. Increased pressure drop, reduced mass flow rate, and deteriorated port flow efficiency could be the consequences leading to higher emissions, increased fuel consumption, and higher knock sensitivity. The optimization of the individual ports by computational fluid dynamics (CFD) is a proper means to minimize or even delete these drawbacks. Meanwhile, there are several powerful optimization methods for three-dimensional flows on the market. In this paper, a combined optimization strategy using CFD topology optimization followed by a shape optimization is presented. The proposed method has been applied to an I3 engine with two separate integrated exhaust manifolds
Hopf, Anselm, Bartsch, Günter, Krämer, Frank, Weber, Carsten
Influence of Coolant Temperature and Flow Rate, and Air Flow on Knock Performance of a Downsized, Highly Boosted, Direct-Injection Spark Ignition Engine2017-01-066403/28/2017
The causes of engine knock are well understood but it is important to be able to relate these causes to the effects of controllable engine parameters. This study attempts to quantify the effects of a portion of the available engine parameters on the knock behavior of a 60% downsized, DISI engine running at approximately 23 bar BMEP. The engines response to three levels of coolant flow rate, coolant temperature and exhaust back pressure were investigated independently. Within the tested ranges, very little change in the knock limited spark advance (KLSA) was observed. The effects of valve timing on scavenge flow and blow through (the flow of fresh air straight into the exhaust system during the valve overlap period) were investigated at two conditions; at fixed inlet/exhaust manifold pressures, and at fixed engine torque. For both conditions, a matrix of 8 intake/exhaust cam combinations was tested, resulting in a wide range of valve overlap conditions (from 37 to -53°CA). The results
Asif, Mohd, Giles, Karl, Lewis, Andrew, Akehurst, Sam, Turner, Niall
Thermodynamic Potential of Electrical Turbocharging for the Case of Small Passenger Car ICE under Steady Operation2017-01-052603/28/2017
The proposed paper deals with thermodynamic optimization of highly flexible ICE (variable compression ratio, intake/exhaust VVA) while comparing e-turbocharging concept with classical one. The e-turbocharging approach is based on idea that compressor/turbine has its own electric machine (motor/generator) and that additional electric energy can be supplied/attached from/to engine crank train. Hence it allows independent control of compressor/turbine. On the other hand, classical approach is based on a standard mechanical connection between turbine and compressor. The whole system (flexible engine + boost device) is optimized under steady operation – low load (BMEP of 4 bar), medium load (BMEP of 13 bar), high load (BMEP of 30, 25 and 18 bar) and maximum load are considered. Moreover, 3 combustion concepts are considered – classical SI and CI, and ideal RCCI. Sensitivity study of selected parameters is performed: e.g., efficiency of electric machine(s), HP exhaust manifold volume. All
Vitek, Oldrich, Macek, Jan
Thermomechanical Analysis of Diesel Engine Exhaust Manifold2016-36-025810/25/2016
This study focuses on the Termomechanical Fatigue (TMF) analysis for an exhaust manifold. Bolt tension and temperature field has been applied in order to get variation on stresses, going from room load condition to a full load condition. The temperature field has been acquired from 1D simulation and adjusted to fit experimental values measured on the vehicle. Low cycle fatigue (LCF) has been considered to evaluate the exhaust manifold under the stress cycles produced by temperature fluctuation. Thermal and stress analysis have been performed by Abaqus package. An in-house code has been employed in the fatigue analysis. The bolt torque and the temperature field on the engine and exhaust manifold are the loads considered in the analysis.
de Azevedo Cardoso, Ademar, Andreatta, Ederson Claudio
Investigations on Ventilation Strategies for SI Cylinder Deactivation Based on a Variable Valve Train2016-01-234610/17/2016
Advanced SI engines for passenger cars often use the cylinder deactivation technology for dethrottling and thus achieving a reduction of fuel consumption. The gas exchange valves of the deactivated cylinders are closed permanently by a zero lift of the cams. The solutions for cylinder deactivation can vary in the kind of gas composition included in the deactivated cylinders: charge air, exhaust gas or vacuum. All these strategies have in common the frequent loss of captured charge mass from cycle to cycle. Their two-stroke compression-expansion cycle additionally intensifies this phenomenon. Thus, a significant decrease of the minimum cylinder pressure can cause an undesired entry of lubricant into the combustion chamber. The idea was to ventilate the generally deactivated cylinders frequently to compensate the loss of captured cylinder charge mass. The task was to keep the minimum cylinder pressure above a certain limit to prevent the piston rings from a failure. However, a compromise
Gottschalk, Wolfram, Fink, Rene, Schultalbers, Matthias
Thermo-Mechanical Fatigue Study of Gasoline Engine Exhaust Manifold Based on Weak Coupling of CFD and FE2016-01-235010/17/2016
This paper combines fluid software STAR-CCM+ and finite element software ABAQUS to solve the temperature field of this Gasoline engine exhaust manifold based on loose coupling method. Through the simulation of car parking cooling - full load condition at full speed, we estimate thermal fatigue life of the exhaust manifold with the plastic strain increment as the evaluation parameters. It can guide the direction of optimal design of the exhaust manifold. Here we also revealed how the bolt force affects the manifold elastic and plastic behavior.
Liu, Zhien, Chen, Jiangmi, Xiao, Sheng-hao
Concept Analysis and Initial Results of Engine-Out NOx Estimator Suitable for on ECM Implementation2016-01-061104/05/2016
The interest for NOx estimators (also known as virtual sensors or inferential sensors) has increased over the recent years due to benefits attributed to cost and performance. NOx estimators are typically installed to improve On-Board Diagnostics (OBD) monitors or to lower bill of material costs by replacing physical NOx sensors. This paper presents initial development results of a virtual engine-out NOx estimator planned for the implementation on an ECM. The presented estimator consists of an airpath observer and a NOx combustion model. The role of the airpath observer is to provide input values for the NOx combustion model such as the states of the gas at the intake and exhaust manifolds. It contains a nonlinear mean-value model of the airpath suitably transformed for an efficient and robust implementation on an ECM. The airpath model uses available sensory information in the vehicle to correct predictions of the gas states. The NOx combustion model is a crank-angle resolved model of
Kihas, Dejan, Pachner, Daniel, Baramov, Lubomir, Uchanski, Michael, Naik, Priya, Khaled, Nassim
Thermal Analysis of Heavy Duty Engine Exhaust Manifold Using CFD2016-01-064804/05/2016
The exhaust manifold bridges the gap between the engine structure and the hot-end after-treatment system, the burned in-cylinder gases are disposed through the manifold. The automotive exhaust manifolds are designed and developed for providing a smooth flow with low/least back pressure and must be able to withstand extreme heating under very high temperatures and cooling under low temperatures. The paper presents a theoretical study aiming to investigate the feasibility of three different CAE approaches and techniques used for the simulation of exhaust manifold fluid flow and the accompanying thermal distribution. The main difficulty emanates from the pulsating nature of fluid flow inside the engine exhaust manifold. To verify the outcome of each solution experimental measurements of the manifold temperatures have been performed. The predicted metal temperature is then used to carry out the thermo-structure durability analysis to evaluate the design of HD diesel engine exhaust manifold
Eroglu, Sinan, Duman, Ipek, Ergenc, Alp, Yanarocak, Rıfat
The Analysis of Phase Separation in Vertical Headers of Microchannel HEs2016-01-025304/05/2016
This paper presents the experimental analysis of separation in vertical headers based on flow visualization. Two-phase separation phenomena inside the header is observed and quantified. Driving forces are analyzed to study the mechanisms for two-phase flow motion and flow regimes. Main tube of the header is made of clear PVC for visualization study. R-134a is used as the fluid of interest and the mass flux from the inlet pass is 55 kg/m2s - 195 kg/m2s. Potential ways to improve two-phase separation are discussed. A model is built to show how separation brings potential benefits to MAC heat exchangers by arranging the flow path.
Li, Jun, Hrnjak, Predrag
Development of a New 2.0L I4 Turbocharged Gasoline Direct Injection Engine2016-01-101704/05/2016
It is important to take action regarding environmental issues on a global scale, and automakers are adding downsized turbocharged engines to their line-ups as a means of reducing CO2 emissions, particularly in Europe. Honda has recently announced a next-generation powertrain series that realizes a good balance between environmental performance and driving pleasure. As part of this series, the company has developed a downsized and turbocharged 2.0L gasoline direct injection engine. This is a high-powered sports car engine positioned in the European “hot hatch” category. The development balanced engine power with good environmental performance. The new powertrain featured a range of technologies to enable these demands to be satisfied, including a high-tumble port, a dual VTC(Valve Timing Control),variable exhaust valve lift mechanism, a two-piece water jacket for the exhaust manifold, which has been integrated with the cylinder head, a mono-scroll turbocharger, pistons equipped with
Jono, Mitsutaka, Taguchi, Masayuki, Shonohara, Toshimitsu, Narihiro, Shigeru
A Virtual Residual Gas Sensor to Enable Modeling of the Air Charge2016-01-062604/05/2016
Air charge calibration of turbocharged SI gasoline engines with both variable inlet valve lift and variable inlet and exhaust valve opening angle has to be very accurate and needs a high number of measurements. In particular, the modeling of the transition area from unthrottled, inlet valve controlled resp. throttled mode to turbocharged mode, suffers from small number of measurements (e.g. when applying Design of Experiments (DoE)). This is due to the strong impact of residual gas respectively scavenging dominating locally in this area. In this article, a virtual residual gas sensor in order to enable black-box-modeling of the air charge is presented. The sensor is a multilayer perceptron artificial neural network. Amongst others, the physically calculated air mass is used as training data for the artificial neural network. The air mass calculation is performed by taking into account valve timing, effective valve cross-sectional area and low-pressure indication at intake and exhaust
Raidt, Benedikt
Investigation of the Gas Exchange (Scavenging) on a Single-Scroll Turbocharged Four Cylinder GDI Engine2016-01-102404/05/2016
For scavenging the combustion chamber during the gas exchange, a temporary positive pressure gradient between the intake and the exhaust is required. On a single-scroll turbocharged four cylinder engine, the positive pressure gradient is not realized by the spatial separation of the exhaust manifold (twin-scroll), but by the use of suitable short exhaust valve opening times. In order to avoid any influence of the following firing cylinder onto the ongoing scavenging process, the valve opening time has to be shorter than 180 °CA. Such a short valve opening time has both, a strong influence on the gas exchange at the low-end torque and at the maximum engine power. This paper analyzes a phenomenon, which occurs due to short exhaust valve opening durations and late valve timings: A repeated compression of the burned cylinder charge after the bottom dead center, referred to as “recompression” in this paper. By means of a new energetic analysis (available technical work capacity) the
Wolany, Adalbert, Glahn, Claus, Berner, Hans-Juergen, Bargende, Michael
Probabilistic Isothermal, Anisothermal, and High-Temperature Thermo-Mechanical Fatigue Life Assessment and CAE Implementations2016-01-037004/05/2016
Fatigue life assessment is an integral part of the durability and reliability evaluation process of vehicle exhaust components and systems. The probabilistic life assessment approaches, including analytical, experimental, and simulation, CAE implementation in particular, are attracting significant attentions in recent years. In this paper, the state-of-the-art probabilistic life assessment methods for vehicle exhausts under combined thermal and mechanical loadings are reviewed and investigated. The loading cases as experienced by the vehicle exhausts are first categorized into isothermal fatigue, anisothermal fatigue, and high-temperature thermomechanical fatigue (TMF) based on the failure mechanisms. Subsequently, the probabilistic life assessment procedures for each category are delineated, with emphasis on product validation. Finally, two examples: an isothermal fatigue life assessment for a welded exhaust sub-system, and a high-temperature TMF life assessment for an exhaust
Wei, Zhigang, Qu, Yunfei, Jiang, Dongying, Luo, Limin, Hamilton, Jason, Ellinghaus, Kay, Pieszkalla, Markus
Durability Analysis of Heavy Duty Engine Exhaust Manifold Using CFD-FE Coupling2016-01-037504/05/2016
The exhaust manifold is one of the engine components which is used to collect the burned gases from the cylinder head and send it to the exhaust hot end aftertreatment system with low engine backpressure. The main purpose of the automotive exhaust manifolds are providing a smooth flow field and must be able to endure thermo-mechanical loadings. The present paper explains the CAE analysis method to assess the design of exhaust manifold of a heavy duty diesel engine. Coupled computational fluid dynamics (CFD) analyses were performed to solve the flow field within the exhaust system and surface convection loading prediction at fluid side and obtain temperature distribution at solid region of exhaust manifold domain. The metal temperature prediction provided by thermal model is used to carry out the durability analysis of the structure. A transient nonlinear Finite Element Analysis (FEA) is undertaken to simulate the inelastic deformation and predict thermo-mechanical fatigue (TMF) failure
Eroglu, Sinan, Duman, Ipek, Guzel, Ahmet Hamdi, Yilmaz, Rifat
NVH Development of the Ford 2.7L 4V-V6 Turbocharged Engine2015-01-228806/15/2015
A new turbocharged 60° 2.7L 4V-V6 gasoline engine has been developed by Ford Motor Company for both pickup trucks and car applications. This engine was code named “Nano” due to its compact size; it features a 4-valves DOHC valvetrain, a CGI cylinder block, an Aluminum ladder, an integrated exhaust manifold and twin turbochargers. The goal of this engine is to deliver 120HP/L, ULEV70 emission, fuel efficiency improvements and leadership level NVH. This paper describes the upfront design and optimization process used for the NVH development of this engine. It showcases the use of analytical tools used to define the critical design features and discusses the NVH performance relative to competitive benchmarks.
Zouani, Abdelkrim, Stout, Joseph, Hanim, Salah, Gan, Changshen, Dziubinschi, Gabriela, Baldwin, William, Fu, Zhi
Development of the Combustion System for General Motors' High-Efficiency Range Extender Ecotec Small Gas Engine2015-01-127204/14/2015
General Motors has developed an all-new Ecotec 1.5 L range extender engine for use in the 2016 next generation Voltec propulsion system. This engine is part of a new Ecotec family of small displacement gasoline engines introduced in the 2015 model year. Major enhancements over the range extender engine in the current generation Voltec propulsion system include the adoption of direct injection (DI), cooled external exhaust gas recirculation (EGR), and a high 12.5:1 geometric compression ratio (CR). Additional enhancements include the adoption of high-authority phasers on both the intake and exhaust camshafts, and an integrated exhaust manifold (IEM). The combination of DI with cooled EGR has enabled significant thermal efficiency gains over the 1.4 L range extender engine in the current generation Voltec propulsion system at high engine loads. The addition of a high geometric CR and high-authority camshaft phasers for extended late intake valve closing (LIVC) operation has enabled
Jocsak, Jeffrey, White, David, Armand, Cedric, Davis, Richard S.
Exhaust Manifold Durability Subject to Splash Quenching2015-01-173504/14/2015
Exhaust manifold design is one of the more challenging tasks for the engine engineer due to the harsh thermal and severe vibration environment. Extremely high exhaust gas temperatures and dynamic loading combine to subject the manifold to high cyclic stress when the material has reduced fatigue strength due to the high temperature. A long service life before a fatigue failure is the objective in exhaust manifold design. Accumulation of fatigue damage can occur from dynamic loading and thermal loading combined. Thermal mechanical fatigue (TMF) is a primary mechanism for accumulating fatigue damage. TMF typically occurs when a vehicle driving cycle has operating conditions that repeatedly change the exhaust gas temperature between hot and cold. Another way to experience temperature cycling is through splash quenching. Splash quenching was analyzed and found to rapidly accumulate fatigue damage. An experimental and analytical method is presented that quantified splash quenching and the
Wade, Robert, Hsieh, Jerry C.
Turbocharger Matching Method for Reducing Residual Concentration in a Turbocharged Gasoline Engine2015-01-127804/14/2015
In a turbocharged engine, preserving the maximum amount of exhaust pulse energy for turbine operation will result in improved low end torque and engine transient response. However, the exhaust flow entering the turbine is highly unsteady, and the presence of the turbine as a restriction in the exhaust flow results in a higher pressure at the cylinder exhaust ports and consequently poor scavenging. This leads to an increase in the amount of residual gas in the combustion chamber, compared to the naturally-aspirated equivalent, thereby increasing the tendency for engine knock. If the level of residual gas can be reduced and controlled, it should enable the engine to operate at a higher compression ratio, improving its thermal efficiency. This paper presents a method of turbocharger matching for reducing residual gas content in a turbocharged engine. The turbine is first scaled to a larger size as a preliminary step towards reducing back pressure and thus the residual gas concentration in
Ismail, Muhammad Izzal, Costall, Aaron, Martinez-Botas, Ricardo, Rajoo, Srithar
Analysis of Engine Walls Thermal Insulation: Performance and Emissions2015-01-166004/14/2015
This paper presents an experimental analysis on the effect of thermal insulation of engine internal walls on the performance and emissions of a heavy-duty diesel engine. Some parts of the engine, like pistons, cylinder head and exhaust manifold were thermally insulated from gas contact side in order to reduce heat losses through the walls. Each component has been analyzed, independently, and in combination with others. The results have been compared with that of the original engine configuration. The analysis focuses on NOx and, smoke emissions along with brake specific fuel consumption. In order to take advantage of the engine insulation, an optimization of the air management and injection settings was finally performed, which provided the best combination for each engine configuration. The results showed that, on the one hand maintaining the same level of NOx, soot emissions is reduced using insulated cylinder head and insulated pistons, but these configurations increase the fuel
Serrano, Jose Ramon, Arnau, Francisco Jose, Martin, Jaime, Hernandez, Manuel, Lombard, Benoit
Effect of Temperature Cycle on Thermomechanical Fatigue Life of a High Silicon Molybdenum Ductile Cast Iron2015-01-055704/14/2015
High silicon molybdenum (HiSiMo) ductile cast iron (DCI) is commonly used for high temperature engine components, such as exhaust manifolds, which are also subjected to severe thermal cycles during vehicle operation. It is imperative to understand the thermomechanical fatigue (TMF) behavior of HiSiMo DCI to accurately predict the durability of high temperature engine components. In this paper, the effect of the minimum temperature of a TMF cycle on TMF life and failure behavior is investigated. Tensile and low cycle fatigue data are first presented for temperatures up to 800°C. Next, TMF data are presented for maximum temperatures of 800°C and minimum cycle temperatures ranging from 300 to 600°C. The data show that decreasing the minimum temperature has a detrimental effect on TMF life. The Smith-Watson-Topper parameter applied at the maximum temperature of the TMF cycle is found to correlate well with out-of-phase (OP) TMF life for all tested minimum temperatures. Fractography and
Avery, Katherine, Pan, Jwo, Engler-Pinto, Carlos
Comparative Assessment of Elastio-Viscoplastic Models for Thermal Stress Analysis of Automotive Powertrain Component2015-01-053304/14/2015
In this paper, thermal stress analysis for powertrain component is carried out using two in-house developed elasto-viscoplastic models (i.e. Chaboche model and Sehitoglu model) that are implemented into ABAQUS via its user subroutine UMAT. The model parameters are obtained from isothermal cyclic tests performed on standard samples under various combinations of strain rates and temperatures. Models' validity is verified by comparing to independent non-isothermal tests conducted on similar samples. Both models are applied to the numerical analysis of exhaust manifold subject to temperature cycling as a result of vehicle operation. Due to complexity, only four thermal cycles of heating-up and cooling-down are simulated. Results using the two material models are compared in terms of accuracy and computational efficiency. It is found that the implemented Chaboche model is generally more computationally efficient than Sehitoglu model, though they are almost identical in regard to accuracy
Mao, Jianghui, Engler-Pinto, Carlos, Su, Xuming
A Study of a Highly Boosted and Efficient Downsized Ethanol Direct Injection (EDI) Engine in Two Different Configurations for the Purpose of Replacing High-Displacement Gasoline Engines2015-01-125504/14/2015
The paper presents a layout of a highly boosted Ethanol Direct Injected (EDI) engine with extreme downsizing, which represents a powerful means to reduce emissions at reduced production costs. The substitution of high-displacement engines (2.4- or 3.0-liter) by a downsized turbocharged EDI-engine is studied. The paper describes the detailed layout of all engine hardware and in particular, the cylinder head structure including the optimized intake and exhaust manifolds as well as implemented DI injectors. The paper continues with a presentation of the experimental data obtained at the engine test rig. The paper concludes presenting a series of experimental data obtained with the downsized engine mounted in a car as a replacement for its original high-displacement engine.
Pontoppidan, Michael, Baeta, Jose G. C.
The New Toyota 1.2-Liter ESTEC Turbocharged Direct Injection Gasoline Engine2015-01-126804/14/2015
Toyota Motor Corporation is developing a series of engines belonging to its ESTEC (Economy with Superior Thermal Efficient Combustion) development concept. This paper describes the development of 8NR-FTS after the subsequent launch of the 2.0-liter DI Turbocharged 8AR-FTS. 8NR-FTS is a 1.2-liter inline 4-cylinder spark ignition downsized turbocharged direct injection (DI) gasoline engine. By following the same basic concepts as 8AR-FTS engine [1], the 8NR-FTS incorporates various fuel efficient technologies such as a cylinder head with an integrated exhaust manifold, the Atkinson cycle using the center-spooled variable valve timing with mid-position lock system (VVT-iW), and intensified in-cylinder turbulence to achieve high-speed combustion. Instead of the D-4ST (Direct injection 4-stroke gasoline engine Superior version with Turbo) system that incorporates port and direct injection, this engine adopts the D-4T (Direct injection 4-stroke gasoline engine with Turbo) system that
Shinagawa, Tomohiro, Kudo, Masahito, Matsubara, Wataru, Kawai, Takashi
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