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The aim of this paper is to extend the evaluation of the accuracy of published 1-D pressure loss coefficients which are used in 1-D gas dynamics models, in unsteady compressible flows propagating in the exhaust pulses in manifolds. These pressure loss coefficients were derived from the conservation of linear momentum over finite control volumes based on assumptions including steady flow. The objectives of this work were to evaluate the accuracy of the pressure loss coefficients over the type of flows generated by engine-like pressure pulses propagating in a range of three-pipe junctions. The evaluation was performed by reference to results from unsteady, compressible, 3-D Reynolds-averaged computational fluid dynamic (CFD - open source software OpenFOAM) simulations. Two of the junction branches represented the exhaust pipes from two cylinders and the remaining was the outlet pipe. All pipes had a diameter of 25mm with length ratio 1:2 between inlet and outlet.

In this work a soot source term tabulation strategy for soot predictions under Diesel engine conditions within the zero-dimensional Direct Injection Stochastic Reactor Model (DI-SRM) framework is presented. The DI-SRM accounts for detailed chemistry, in-homogeneities in the combustion chamber and turbulence-chemistry interactions. The existing implementation [1] was extended with a framework facilitating the use of tabulated soot source terms. The implementation allows now for using soot source terms provided by an online chemistry calculation, and for the use of a pre-calculated flamelet soot source term library. Diesel engine calculations were performed using the same detailed kinetic soot model in both configurations. The chemical mechanism for n-heptane used in this work is taken from Zeuch et al. [2] and consists of 121 species and 973 reactions including PAH and thermal NO chemistry. The engine case presented in [1] is used also for this work.

Nowadays the high competition reached by the automotive market forces Original Equipment Manufacturers (OEMs) towards innovative solutions. Strict emission standards and fuel economy targets make the work hard to be accomplished. Therefore modern engines feature complex architecture and embed new devices for Exhaust Gas Recirculation (EGR), turbocharging (e.g. multi-stage compressors), gas after-treatment (e.g. the Selective Catalyst Reduction (SCR)) and fuel injection (either high or low pressure). In this context the Engine Management System (EMS) plays a fundamental role to optimize engine operation. The paper deals with fuel spray and combustion simulation by a multi-zone phenomenological model aimed at the steady-state optimal tuning of the injection pattern.

One of the favored automotive exhaust aftertreatment solutions used for nitrogen oxides (NOx) emissions reductions is referred to as Selective Catalytic Reduction (SCR), which comprises a catalyst that facilitates the reactions of ammonia (NH3) with the exhaust nitrogen oxides (NOx). It is customary with these systems to generate the NH3 by injecting a liquid aqueous urea solution (AUS-32) into the exhaust. The urea solution is injected into the exhaust and transformed to NH3 by various mechanisms for the SCR reactions. Understanding the spray performance of the AUS-32 injector is critical to proper optimization of the SCR injection system. Results were previously presented from imaging of an AUS-32 injector spray under hot exhaust conditions at the injector spray exit for an exhaust injection application.

The vast stores of biomass available worldwide have the potential to displace significant amounts of petroleum fuels. Fast pyrolysis of biomass is one of several possible paths by which we can convert biomass to higher value products. Pyrolysis oil (PO) derived from wood has been regarded as an alternative fuel to be used in diesel engines. However, the use of PO in a diesel engine requires engine modifications due to the low energy density, high acidity, high viscosity, high water content, and low cetane number of PO. The easiest way to adopt PO without engine modifications is blending with other fuels that have a high cetane number. However, PO has poor miscibility with light petroleum fuel oils; the most suitable candidate fuels for direct fuel mixing are alcohol fuels. Early mixing with alcohol fuels has the added benefit of significantly improving the storage and handling properties of the PO.

Extending the lean limit or/and exhaust-gas-recirculation (EGR) limit/s are necessary for improving fuel economy in spark ignition engines. One of the major problems preventing the engine to operate at lean conditions is stable and successful initial ignition kernel formation. A repeatable, stabilized ignition and early flame development are quite important for the subsequent part of the combustion cycle to run smooth without partial burn or cycle misfire. This study aims to develop an innovative plasma ignition system for reciprocating combustion engines with an aim to extend lean limit and for high pressure applications. This ignition system utilizes microwaves to generate plasma as an ignition source. This microwave plasma igniter is much simplified device compared to conventional spark plug. The microwave plasma ignition system consists of microwave oscillator, co-axial cable and microwave discharge igniter (MDI).

Due to the new challenge of meeting number-based regulations for particulate matter (PM), a numerical and experimental study has been conducted to better understand particulate formation in engines fuelled with compressed natural gas. The study has been conducted on a Heavy-Duty, Euro VI, 4-cylinder, spark ignited engine, with multipoint sequential phased injection and stoichiometric combustion. For the experimental measurements two different instruments were used: a condensation particle counter (CPC) and a fast-response particle size spectrometer (DMS) the latter able also to provide a particle size distribution of the measured particles in the range from 5 to 1000 nm. Experimental measurements in both stationary and transient conditions were carried out. The data using the World Harmonized Transient Cycle (WHTC) were useful to detect which operating conditions lead to high numbers of particles. Then a further transient test was used for a more detailed and deeper analysis.

Particulate matter in vehicular exhaust is now under great scrutiny. In the EU, direct injection spark ignition (DISI) engines running on petrol now have limits for particulate emissions set for both mass and number. Current legislative test procedures represent a best-case scenario - more aggressive driving cycles and lower ambient temperatures can increase particulate emissions massively. Ambient temperature is generally the environmental parameter of most importance regarding particulate emissions from an engine, particularly for the reasonably brief periods of operation typical for passenger cars operating from a cold start. Two Euro 5 vehicles with DI SI engines were laboratory tested at three ambient temperatures on two different commercially available fuels, with particulate emissions results compared to results from the same fuels when the vehicles were tested at 25°C.

Commercial three way catalysts have limited capacity towards reducing NOx in the presence of excessive oxygen. This prevents lean-burn combustion concepts from meeting legislative emission standards. A solution towards decreasing NOx emissions in the presence of excess air is the use of a passive-SCR system. Under rich conditions ammonia is formed over an ammonia formation catalyst, the ammonia is stored in the SCR and in its turn reacts with the NOx under lean engine conditions. Here up-scaled Pt/Al2O3 and Pd/Al2O3 catalysts as well as a commercially Pd-Rh based three-way catalyst (TWC) are evaluated using both engine and further lab-scale tests. The purpose of these tests is to compare the ammonia production for the various catalysts under various lambda values and temperatures by means of engine and lab scale tests. The Pd/Al2O3 showed little sensitivity to temperature both under engine and lab scale experiments.

The aim of the study is to evaluate the possible vanadium emissions from different commercially available vanadium-based SCR monoliths. The vanadium sublimation was studied at laboratory scale using a monolith sample (16 mm diameter × 19 mm long). Vanadia vapors were disposed on an alumina bed placed downstream the catalyst sample, in the hot zone of a furnace. Experiments were carried out with a space velocity of 42 000 h−1. The reactive gas flow was composed of 5%O2, 5%H2O, 500ppm NO and 500ppm NH3. Catalyst samples and alumina bed were exposed to this reactive gas flow during 10 hours at 500°C, 600°C, 650°C, 675°C, 700°C and 750°C, successively. After each test, alumina samples were mineralized from HNO3, HF and HCl mixture. The digests were then diluted with high purity water prior, to ICP-MS analysis. The results revealed that, for full body type catalysts, sublimation of vanadium increases in a significant way from an exposure to the reactive gas flow at 675°C.

Aerospace, automotive and aeronautical control systems demand high performance, precision, accuracy, modularity, integration, dependability and other attributes. Currently, to supply these requirements, engineers are using Networked Control Systems (NCSs) with Time Division Multiple Access (TDMA) databuses. They are part of Distributed Time Based Architectures (DTBAs) that provide the infrastructure for the design and implementation of safety critical distributed systems. These architectures provide a common time basis among the nodes of a system. However, the benefits of this approach face the challenge of establishing a common time basis among the nodes of a distributed system since startup until shutdown. For this, clock synchronization algorithms are used to achieve a common time basis within some precision and/or accuracy among the nodes of a system. So, clock synchronization algorithms become a critical part of designing distributed systems.

Control systems that can switch between control or plant modes have the advantage of being simpler to design than an equivalent system with a single mode. However, the transition between these modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the system. This is can be of extreme importance in fields such as aerospace and automobilistic, as the switching between manual and autopilot modes or the switching of gears In this work, we will use integral criteria in original ways, to determine a coefficient on the system which should optimize the trajectory of the control signal, during the switching between two modes. Effectively, each transition will be done by a subsystem specific for it, according to the selected criterion. The simulations will be made in MATRIXx, MatLab or both, using models chosen from aerospace or automobilistic fields.

One of the usual measures to increase the energy efficiency in automotive vehicles has been the adoption of generators with variable voltage systems, commanded by the vehicle control unit. Thus, the vehicle system voltage no longer remains constant during operation of the engine, but becomes variable as needed to charge the vehicle electrical system and better use of available engine torque. A study using the Design for Six Sigma (DFSS) methodology was performed in order to understand the influence of the supply voltage and of the fuel conductivity in the lifetime of fuel pump commutation system by brushes. Durability tests were conducted in bench test, where parameters of temperature, current draw, voltage and fuel conductivity were monitored, correlating them with the results of wear in the pump commutation system.

This work is developed under the context of determining a suitable power-recirculation gear test design. Its operation parameters are determined by the usual speed values to what the Brazilian automotive transmission systems are submitted. The operating parameters generate forces that act as a frequency source, inducing mechanical vibrations to the structure. The level of the vibrations must be supervised so it does not reach values which correspond to the structure natural frequency. In such cases, resonance zones and noise at the measurement devices occur, causing wrong measurement data and, even further, structural failures. This paper analyzes the application of a method to investigate operational conditions and, eventually, redesign the rig’s main elements, to escape from resonance and noise zones. The modal analysis appears as a suitable tool for this purpose, giving as an output the description of structure natural vibration response.

When new vehicles are being developed and will later be made available to the market, one of the most important characteristics that may influence the buying decision is the comfort available to the driver and passenger inside the vehicle. This comfort is partially limited by NVH issues inside the car for example. With the new technologies development, vehicles have become noiseless and, that’s why some vibrations from fuel supply module that weren't identifiable then now might show themselves a huge impact of noise inside the vehicles. So it is important to analyze the NVH behavior of fuel supply modules. To perform this study in a short time and with low cost, CAE simulations were done focusing on geometry optimization of the pump holder that keeps the electric fuel pump inside the fuel tank.

One-dimensional models for internal combustion engines analysis are very useful to simulate its systems through a relatively low computational effort. Based on this idea, this paper presents the simulation of a spark-ignition engine using one-dimensional models implemented in object oriented programming by the authors. The model was adapted to simulate a research four valves, single cylinder, spark ignition, reciprocating internal combustion engine. The gas in the cylinder was described by conservation equations, including the momentum conservation equation, that wasn’t found in the checked literature. For the combustion, a two zones model was implemented, based on combustion wave equations, such that detonation and deflagration are calculated by the same set of equations. The flame propagation geometry was considered to be spherical.

Induction hardening process is widely used to improve fatigue strength of mechanical components that are subjected to cyclic loads in service. The depth of the hardened layer is directed linked with the fatigue and impact strength. So, to improve the mechanical properties in order to preventing fatigue failure in service, it is very important to understand the process and the influence of its parameters. In this paper, a sensitivity study of the influence of some process parameters on the hardness profile of a crankshaft’s crankpin after induction hardening using will be presented. The proposed simulation method include two stages: heating and cooling. In the first stage, the mechanical component, initially at ambient temperature, is heated by electromagnetic induction to a temperature above the steel austenitization. In the second one, the component is cooled by liquid immersion.

With Advanced PFI, Bosch has demonstrated that gasoline port-fuel injection is becoming significantly more energy-efficient by means of innovative system development. Advanced PFI combines fuel pressure increase, twin injection, PFI scavenging, and open valve injection. The use of Advanced PFI makes it possible to reduce consumption by 12%, with a corresponding decrease in CO2 emissions. The higher compression in the part-load range alone accounts for 2% of the reduction. The remaining 10% come from downsizing with turbocharging and PFI scavenging. At the same time, Advanced PFI allows a reduction in hydrocarbons (HC) emissions. Thanks to more homogenous air-fuel mixture formation and reduced manifold wall fuel condensation, HC emissions fall by 20% in the test cycle. And Advanced PFI also permits an increase in specific engine power output, with PFI scavenging achieving significantly higher low-end torque.

Gasoline direct injection (GDI) engines have very attractive potential for improving fuel economy and exhaust emissions, especially disadvantages of increased fuel consumption at part load. In this research, a study has been made on the investigations of stratified lean combustion in a wall-air guided type spark-ignition single cylinder optical research engine. Experiments were conducted at constant load (NIMEP 3 bar) using ethanol as fuel, for a wide range of injection, ignition and mixture formation parameters. Engine efficiency and combustion stability were evaluated at each excess air ratio. Optical visualization illustrated the spray behavior and flame propagation. Specific fuel consumption improvement was achieved with lean burn mixtures. Thus, combustion analysis data based on in-cylinder pressure measurement provide useful data for ethanol GDI engine development.

Exhaust system noise has significant impact on vehicle exterior and interior noise. In a vehicle development, during early design verification phase, the exhaust tailpipe orifice noise performance is measured and validated at the proving ground tracks using design intent prototype parts developed and delivered by supplier, following previously technical specifications agreements and specific package constrains and targets. At late design verification phase, new measurements are performed in production intent prototype parts, and the results achieved are compared with initial measurements made for design intent prototype parts - with conflicting results in some situations.