No description available.

Published Article / The simulation of an exhaust manifold's thermal behaviour is an important concern for various reasons. Amongst them is the need to minimise catalyst light-offtime as significant exhaust emissions are generated within this period. Modelling such behaviour is not simplistic as it is governed by complex interactions between exhaust gas flow and the manifold itself. Computational fluid dynamics (CFD) is a powerful tool for such simulations. However its applicability for transient simulations is limited by high central processing unit (CPU) demands. The present study proposes an alternative computational method to assess and rank the relative impact of the manifold's thermal properties on its exterior temperature. The results show that stainless steel manifolds potentially minimise heat loss from the exhaust gas when compared with their cast iron counterparts. This may result in an increase in thermal energy being available to heat the catalyst.

The subject of this diploma thesis is optimalization of exhaust manifold of ŠKODA 1,2 MPI engine with respect for the plastic deformation at heat stress. The first part is focused on general description of converter module, whose component the exhaust manifold is. In the next part of the thesis is computation of a heat load of the exhaust manifold. The last part is devoted to the seal analysis of the whole converter module of a ŠKODA three-cylinder engine.

The aim of this diploma thesis is the design and tuning of the exhaust manifold and muffler for the Formula Student car. The single cylinder atmospheric spark ignition engine Husaberg FE 570 is used as a powertrain unit. The exhaust system is designed according to the Formula Student rules. To design the exhaust system has been used as theoretical knowledge as well as software Lotus Engine Simulation.

The subject of this diploma thesis is optimalization of exhaust manifold of ŠKODA 1,2 MPI engine with respect for the plastic deformation at heat stress. The first part is focused on general description of converter module, whose component the exhaust manifold is. In the next part of the thesis is computation of a heat load of the exhaust manifold. The last part is devoted to the seal analysis of the whole converter module of a ŠKODA three-cylinder engine.

The master’s thesis is focused on creating a thermodynamic model of the diesel engine for heavy commercial vehicle. After the model was created, new intake and exhaust pipes are designed based on simulations. Those proposed pipes variants are compared with the series design. After evaluating individual variants, the final version of the new pipes is selected and 3D model for this version is created.

Main goal of this thesis is to design exhaust manifold for Formula Student car Dragon 3. Construction parameters follow requirements on high engine power and also have to meet some restrictions given by competition rules. Lotus Engine Simulation software was used for modelling the engine (originally from Husaberg FE 570 motorcycle) and for determination of influence of the exhaust parameters on power characteristics. This thesis is also dedicated to noise emitted by the exhaust system which is important due to Formula Student rules.

Environmental health awareness has elevated in recent years alongside the evidence that supports the need to mitigate harmful greenhouse gas (GHG) emissions from non-renewable energy resources. The transportation sector alone significantly contributes to the pollutants on a global scale. Although it is commonly used for its superior energy-density and fuel efficiency, diesel engines are a significant portion of the transportation sector that contributes to these pollutants. As a result, this motivates novel research to simultaneously drive fuel efficiency improvements and emissions reductions. <div><br></div><div>The aftertreatment system for a diesel engine is critical in reducing the amount of harmful tailpipe emissions. Efficient operation of these aftertreatment systems generally requires elevated temperatures of 250◦C or above. In this effort, a flexible valvetrain will be utilized to demonstrate fuel-efficient strategies via intake valve closure (IVC) modulation at elevated speeds and loads. In addition, thermal management strategies will be demonstrated at low-to-moderate loads via cylinder deactivation (CDA), cylinder cutout, exhaust valve opening (EVO) modulation, and high-speed idle operation.</div><div><br></div><div>At elevated engine speeds, late intake valve closure (LIVC) enables improved cylinder filling via a dynamic charging effect. It is experimentally and analytically demonstrated that LIVC at 2200 RPM and 7.6 bar to 12.7 bar BMEP can be used to increase the volumetric efficiency and enable higher exhaust gas recirculation fractions without penalizing the air-to-fuel ratio. As a result, efficiency improving injection advances are implemented to achieve 1.2% and 1.9% fuel savings without sacrificing NOx penalties. In order to implement the LIVC benefits on a cammed engine, production-viable valve profile solutions were investigated. It is demonstrated that lost-motion-enabled and/or added-motion-enabled boot shape profiles are capable of improving volumetric efficiency at elevated engine speeds and loads. These profiles were also considered for one (of two) -valve modulation and two-valve modulation. Nearly 95% of the volumetric efficiency benefits are possible using production-viable boot or phase profiles, while 80% of the benefits are possible for single-valve modulation. </div><div><br></div><div>At curb idle, CDA and cylinder cutout operation realize stay-warm aftertreatment thermal management improvements by leveraging their impact on the gas exchange process. Specifically, cylinder cutout demonstrates 17% fuel savings, while CDA demonstrates 40% fuel savings, over the conventional six-cylinder thermal calibration. Additionally, the performance of cylinder cutout is subject to the geometry of the exhaust manifold, location of the EGR loop, and ability to control the exhaust manifold pressure. </div><div><br></div><div>Elevating the idle speed, while maintaining the same idle load, enables improved aftertreatment warm-up performance with engine-out NOx and PM levels no higher than a state-of-the-art thermal calibration at conventional idle operation. Elevated idle speeds of 1000RPM and 1200 RPM, compared to conventional idle at 800 RPM, realized 31% to 51% increase in exhaust flow and 25◦C to 40◦C increase in engine-out temperature, respectively. Additional engine-out temperature benefits are experimentally demonstrated at all three idle speeds considered (800, 1000, and 1200 RPM), without compromising the exhaust flow rates or emissions, by modulating the EVO timing. </div><div><br></div><div>At low-to-moderate loads modern diesel engines manipulate exhaust manifold pressures to drive EGR and thermally manage the aftertreatment. In these engines exhaust manifold pressure control is typically achieved via either a valve after the turbine, a variable geometry turbine, or wastegating. It is experimentally demonstrated that valvetrain flexibility enables efficient engine and aftertreatment operation without requiring exhaust manifold pressure control. Specifically, IVC modulation and CDA at elevated engine speeds, along with EVO modulation, CDA, and internal EGR at low engine speeds can match, or improve, efficiency and thermal management performance compared to a stock thermal calibration that requires exhaust manifold pressure control.<br></div>

The master´s thesis is focused on the design of the intake and exhaust ducts for V8 engine. Home work is focused on the description of the construction of the intake and exhaust pipes for a given engine. Another part deals with creating a thermodynamic model of the engine, and the design of the intake and exhaust pipes. The last part deals with verifying the proposed pipeline construction.

The aim of this diploma thesis is supercharging of SI engines and design influence on performance. The main objective of this thesis is to propose appropriate modifications on AR67203 engine of Alfa Romeo 155Q4 personal vehicle in order to achieve significantly better performance parameters and a constant torque in the widest possible speed range. That is why I analyze design and modifications that affect the overall engine performance and their appropriate application to the selected engine. An important point of this thesis is the right choice of turbocharger, in order to have an effective cooperation with a modified engine. The calculation study and the simulation in Lotus Engine Simulation software serve this purpose. I also give information about ECU programming. The results, as well as a practical output in the form of measured performance parameters of modified engine, are evaluated at the end.