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In most cases, especially in general aviation, the weight of the cooling system should be reduced. In air cooled engines it is necessary to optimize the system taking in account structural features and manufacturing process. This optimization is customary performed by Finite Element Methods (FEM) or similar methods. The main purpose of this paper is to present a way to do the spadework on this problem in order to optimize CPU time of the computer using a simplified approach to obtain approximate values of the more important design parameters of the cooling system. Main assumptions and equations to solve the problem are described for different configurations. Air pressure drop in the system is evaluated checking if it is in good agreement with experimental results. The released software can be installed in a PC, allowing to obtain a first approach of the problem very quickly.

An adsorber system for reducing cold start hydrocarbon (HC) emissions has been developed combining existing catalyst technologies with a zeolite-based HC adsorber. The series flow in-line concept offers a passive and simplified alternative to other technologies by incorporating one additional adsorber substrate into existing converters without any additional valving, purging lines, or special substrates. This contribution describes the current development status of hydrocarbon adsorber aftertreatment technologies. We report results obtained with a variety of adsorber, start-up, and underfloor catalyst system combinations. In each case, it was possible to achieve HC emission levels in compliance with the ULEV standards, and in the best cases, demonstrating HC emissions substantially below the legislated standard.

The in-line hydrocarbon (HC) adsorber is a passive after-treatment technology to address cold-start hydrocarbons in automotive engine exhaust gas. A major technical challenge of the in-line HC adsorber is the difference between the HC release temperature of the adsorber and the light-off temperature of the burn-off (BO) Catalyst. We call this phenomenon the “reversed-temperature difference”. To reduce the reversed temperature difference, NGK has proposed a new “In-line HC Adsorber System” which consists of light-off (LO) Catalyst + Barrel Zeolite Adsorber (BZA), with a hole through the center, BO Catalyst and secondary air injection management (SAE 970266). This, our latest paper, describes the evaluation of various adsorbents and the effect of the center hole on the Adsorber BZA. The adsorber system, which had the Adsorber BZA with a 25mm ϕ center hole and adsorbent coated, confirmed 30% lower FTP NMHC emission versus a system with no center hole or adsorbent coating.

It has long been recognized that the key to achieving stringent emission standards such as ULEV is the control of cold-start hydrocarbons. This paper describes a new approach for achieving excellent cold-start hydrocarbon control. The most important component in the system is a catalyst that is highly active at ambient temperature for the exothermic CO oxidation reaction in an exhaust stream under net lean conditions. This catalyst has positive order kinetics with respect to CO for CO oxidation. Thus, as the concentration of CO in the exhaust is increased, the rate of this reaction is increased, resulting in a faster temperature rise over the catalyst.

To meet LEV and EU Stage III emission requirements, it is necessary for new catalytic converters to be designed which exceed light-off temperature as quickly as possible. The technical solutions are secondary air injection, active heating systems such as the electrically heated catalytic converter, and the close coupled catalytic converter. Engine control functions are extensively used to heat the converter and will to play a significant role in the future. The concept of relocating the converter to a position close to the engine in an existing vehicle involves new conflicts. Examples include the space requirements, the thermal resistance of the catalytic coating and high temperature loads in the engine compartment.

A completely passive cold-start emissions control system, without any secondary air source, was developed to reduce cold start hydrocarbon (HC) emissions. The Air-Less Adsorber (ALA) system has a first catalyst, an adsorber, and a second catalyst. The system is designed to adsorb a large fraction of hydrocarbons (HC) during cold start, followed by optimized heating of the second catalyst before adsorber HC desorption. During the HC desorption cycle, the engine is running in closed-loop control near stochiometric air/fuel ratio. There is enough oxygen to oxidize the desorbed HC over the second catalyst. The ALA system was evaluated using the FTP test on a 3.8 liter V6 vehicle. The ALA system reduced up to 38% of cold start HC emissions beyond the catalyst-only baseline. The system is truly passive.

The introduction of more stringent exhaust emission standards in Europe and in the USA demands substantially more effective exhaust gas treatment than previous standards have prescribed. In SI engines, the cold-start phase is responsible for contributing by far the largest proportion of total emissions. To start the chemical reaction, catalytic converters require a minimum temperature which, at present, cannot be reached quickly enough by the engine exhaust gas. The use of close-coupled main catalytic converters, accurately matched to the engine, offers the potential necessary to achieve compliance with European emission standards. A description of the design procedure and the installation of the series design is provided here followed by a discussion of the advantages and disadvantages of such systems.

Smoke is the most obvious part of the exhaust emitted from Diesel engines. The methods for smoke testing currently used in Taiwan are the rapid acceleration test under no load and the constant speed test under full load. The smoke concentration is measured with the light reflection method. According to the test procedure, the smoke meter sampling time in the rapid acceleration test is 1∼2 seconds. The current range in sampling time may cause discrepancies in test results. In these tests, free acceleration of engine is achieved by actuating the pedal rapidly. However, the speed of engine acceleration has not been defined clearly in the test procedure. The objective of this research is to study the effect of the operating conditions upon the results of smoke tests. Experiments were carried out in this study. The results of measurements showed that the opacity of the engine exhaust increased rapidly after a delay of about 0.3 seconds and then fell.

Number concentration of particles emitted by combustion engines has recently attracted attention, due to the fact that particles of the size range found in tail pipe emissions are suspected of being hazardous to human health. This paper describes the application of an Electrical Low Pressure Impactor (ELPI) to the measurement of number concentrations of diesel exhaust particles. The size distribution of particles as fine as 30 nm is determined using the aerodynamic diameter as the characteristic dimension. Results were obtained on both the engine and chassis dynamometer, in real-time, for steady state and transient tests. Swedish Environmental Class 1 diesel fuel was used, having a sulfur content of less than 10 ppm wt. A scheme for the calculation of particle losses in the sampling system was developed, showing high penetration of particles under the conditions examined.

This paper describes a method used to compare the emissions from transient operation of an engine with the emissions from steady state operating modes of the engine. Weightings were assigned to each mode based on the transient cycle under evaluation. The method of assigning the weightings for each mode took into account several factors, including the distance between each second of the transient cycle's speed-and-torque point requests (in a speed vs. torque coordinate system) and the given mode. Two transient cycles were chosen. The transient cycles were taken from actual in-use data collected on nonroad engines during in-field operation. The steady state modes selected were based on both International Standard Organization (ISO) test modes, as well as, augmentation based on contour plots of the emissions from nonroad diesel engines. Twenty-four (24) steady-state modes were used. The transient cycle's speed-and-torque points are used to weight each steady state mode in the method.

TEOM® monitors where introduce about fifteen years ago to provide engineers with real-time information about the particulate mass concentrations of diluted diesel exhaust. The instrument has gone though a number of changes over the years to reflect the current state of technology and the changing state of particulate regulations. This paper discusses the changes that have taken place in the instrument and performs a series of tests to determine the impact of: filter temperature, filter face velocity, filter pressure drop, and filter conditioning. The testing identified the item with the greatest impact is temperature. Lastly a method for setting up TEOM® monitor to optimize the filter loading and data quality is set out.

Emissions testing of new heavy-duty engines is performed to ensure compliance with governmental emissions standards. This testing involves operating the engine through the heavy-duty engine transient Federal Test Procedure (FTP). While in-use engine emissions testing would be beneficial in aiding regions to meet standards dictated by the Clean Air Act, the process of removing the engine from the vehicle, fitting it to an engine dynamometer, testing, and refitting the engine in the chassis, combined with costs associated with removing the vehicle from service, is expensive. A procedure for engine emissions testing with the engine in the vehicle using a chassis dynamometer was developed to mimic the FTP. Data from two engines and vehicles (a 195 hp 1994 Navistar T 444E in a single axle straight truck and a 1995 370 hp Cummins N-14 in a tandem drive axle tractor) are presented as well as correlation between engine and chassis emissions tests.

This report summarizes the development work for the US06 Low Power Vehicle Adjustment (LPVA) algorithm for the Supplemental Federal Test Procedure (SFTP). The algorithm is integrated into the control software of a 48 inch (1219 mm) single roll electric dynamometer, and temporarily assists vehicles by reducing the road load. To qualify for assistance, vehicles must accumulate 7 seconds of wide-open-throttle (WOT) within any of five prescribed windows of time during the US06 test. WOT is defined as 85-100% of the vehicle's throttle position sensor (TPS) output. The assistance continues until the TPS signal falls below the 85% criterion. The assistance typically lasts 1 second before WOT is relieved and yields approximately 8 seconds of total WOT condition. The LPVA algorithm has been successfully tested on a number of vehicles with a range of data acquisition rates.

Eddy current dynamometers, while less expensive than full inertia dynamometers, have rarely been considered viable alternatives when it comes to transient simulation. Improvements made to eddy current dynamometers in order to meet California's BAR-97 Specification, however, may reverse that thinking in I/M enviromnents.

A new fast response NO detector, based on the chemiluminescence (CLD) method has been used to measure continuous, real time levels of NO in the cylinder, and simultaneously in the exhaust port of a virtually unmodified production SI engine. The real time NO concentration data show a great deal of information. Simultaneous NO measurements taken in-cylinder at sample points a few millimetres apart show substantial differences. Exhaust and in-cylinder levels from the same cycle show even greater differences, though the levels on average are well correlated.

The maturity of Computational Fluid Dynamics methods and the increasing computational power of today's computers has allowed the automotive industry to integrate CFD into the mainstream design process in many areas. As the application of CFD technology is moving from the component level analysis to the system level, the complexity and the size of the models increases continuously. A successful simulation requires synergy between CAD, grid generation, solvers and post-processing so that a timely solution can be obtained that influences the design directions. The complexity of the simulations introduces several issues that affect the acceptance of these methods including but not limited to the accuracy, grid independence, influence of boundary conditions, level of geometry detail. The investigation of these issues is the purpose of the current work.

This paper will deal with an emerging technology in the world of design known as Knowledge-Based Design, or KBE. KBE, also known as Rule-Based Design, provides the design engineer with the ability to develop a true virtual prototype of a product prior to committing to manufacturing. A virtual prototype is a combination of the design rules, or product model, and the vehicle geometry. A virtual prototype has all of the geometric characteristics, or attributes, of the product as well as all of the non-geometric attributes such as materials, mass properties, stress and deflection characteristics, etc. KBE allows the development of computer-based tools for the design engineer that extends beyond the capability of current CAD and parametric tools. The early stages of automobile design differs from the traditional method used in aircraft or marine design where there is a well-defined conceptual, or early stage, design phase.

The objective of the development of the aerodynamic drag predictive tool CDaero was for use as a module for the Automobile Design Support System (AutoDSS). CDaero is an empirically based drag coefficient predictive tool based initially on the MIRA (Motor Industry Research Association) algorithm. The development philosophy was to be able to predict the aerodynamic drag coefficient of an automobile with knowledge of the features of the surface geometry control curves. These are the curves that control the 3-dimensional geometry as seen in the profile, plan and front and rear views. CDaero has been developed in a computing environment using the equation solver TKSolver™. Fifty-one input feature values are first determined from the automobile geometry and then entered into the program. CDaero models the drag coefficient with thirteen different components covering the basic body, as well as additional components such as the wheels, mud flaps, etc.

The principal development tool for the vehicle aerodynamicist continues to be the full-scale wind tunnel. It is expected that this will continue for many years in the absence of a reliable alternative. As a true simulation of conditions on the road, the conventional full-scale wind tunnel has limitations. For example, the ground is fixed relative to the vehicle, allowing an unrepresentative boundary layer to develop, and the wheels of the test vehicle do not rotate. These limitations are known to influence measured aerodynamic data. In order to improve the representation of road conditions in the wind tunnel, most of the techniques used have attempted to control the ground plane boundary layer. Only at model scale has the introduction of a moving ground plane and rotating wheels been widely adopted. The Pininfarina full-scale wind tunnel now incorporates the Ground Effect Simulation System which allows testing with a moving belt and rotating wheels.