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Technical Paper

Application of Shape Memory Heat Engines to Improving Vehicle Fuel Economy

1996-04-01
91A128
Shape memory materials undergo temperature-induced martensitic phase transformations that involve reversible dimensional changes. In performing these changes in shape, the shape-memory material is able to do work against external constraints, and this is the basis for shape-memory low-temperature heat engines. The transformation temperatures on heating and cooling are often not very different (little hysteresis) and are well defined and reproducible. Furthermore, these temperatures can be adjusted by varying the composition of the shape memory alloy. Internal combustion engines dissipate approximately two-thirds of the fuel energy as heat to the exhaust and coolant systems. A low-temperature heat engine could convert a fraction of this heat energy to useful work. This paper discusses the conceptual basis for the application of shape memory heat engines to internal combustion engine powered vehicles. Metallurgical and thermodynamic factors are discussed, as well as engine efficiency.
Technical Paper

Simulors, An Innovative Tool for Molds Development

1996-04-01
91A117
Mold designers and foundrymen spend a lot of time in developing molds without knowing exactly the phenomena which take place inside. Simulor, which has been used in an industrial environment for two years, offers the solution to make foundrymen understand what happens during the filling of the mold and the solidification of the part. Based on navier-stokes and heat transfer equations, simulor provides speed distribution and metal front evolution in the cavity and thermal map in the mold and the part. Some examples with different metals (cast iron, aluminum alloy) cast with various processes (sand or die casting, low pressure or gravity casting) will be given. This new tool will given foundrymen the opportunity to test the mold before having it machined and will also allow reduction in development delays.
Technical Paper

Engine Control System for Lean Combustion

1988-03-01
871171
In order to achieve lean burn engine control system, it is necessary to develop high accuracy air fuel ratio control technology including transient driving condition and lean burn limit expansion technology. This paper describes the following. 1 The characteristics of the transient response of the fuel supply are clarified when various kinds of air flow measuring methods and fuel injection methods are used. 2 To achieve stable combustion in lean mixture, fine fuel droplet mixture, whose diameter is less than 40 μm, needs to be supplied.
Technical Paper

Factors Influencing Petrol Consumption as Determined from a Survey of the Australian Passenger Car Fleet

1988-03-01
871160
A survey of the on-road petrol consumption of Australian passenger cars provided data which has been analysed for effects on fuel consumption caused by features such as transmission type, vehicle inertia class, engine size, air conditioning presence and vehicle location. Results show that cars with automatic transmissions consistently have higher petrol consumption than manuals for all inertia classes - 15% higher in city conditions and 11% higher in highway conditions. There is also a penalty for automatic transmissions at most engine sizes, although the penalty is relatively larger for smaller engine capacities. Presence of air conditioning was found to increase petrol consumption by 13.5% on average, but the data did not allow the impact of frequency of use to be determined. Coastal driving conditions resulted in petrol consumption being 9.4% higher than for inland conditions, and cars driven in winter had 4.4% greater fuel consumption than cars driven in summer.
Technical Paper

Input Loading for Squeak & Rattle CAE Analysis

1999-05-17
1999-01-1726
A method to create a CAE load by utilizing the vibration motions at structure attachments has been developed. This method employs the concept of enforced motion as the constraints of boundary conditions to create an equivalent input force/moment matrix for a sub-structure with multi-point attachments. The main assumption is that motions at the attachments of the sub-structure should be the same as the known motions of the main structure under the generated input load. The key concept of the developed methodology is the calculation of the input dynamic compliance matrix for sub-structure attachment locations. This method is developed to create a system level input load to be used for squeak and rattle CAE analysis on a component or sub-system. It can also be used for minor component design change evaluation using only the component CAE model, yet as if it is assembled in the vehicle.
Technical Paper

Developing Robust Vibration Excitation and Control Methods for Evaluating Rattle Noise in Automotive Components

1999-05-17
1999-01-1725
The authors participated in a task force that was required to develop a repeatable, dependable, and reliable test procedure to compare, rate, and evaluate the severity of rattles. The assemblies involved in the study are designed and manufactured by different companies and are tested by different people on test equipment and instrumentation from different suppliers. The challenges therefore, were considerable and involved both the vibration inputs and responses as well as the acoustic responses. At the beginning of this activity, it was observed that different test labs using the same Ford vibration specs were obtaining different sounds from the same test item! Clearly, this was unacceptable and the test methods had to be improved and standardized. This paper focuses on vibration related to rattle testing. The particular assemblies used in this study were seat belt retractors.
Technical Paper

The Effects of Retained Fluid and Humidity on the Evacuation of Critical Vehicle Systems

1999-05-10
1999-01-1630
In automotive assembly facilities worldwide, many critical vehicle systems such as brakes, power steering, radiator, and air conditioning require the appropriate fluid to function. In order to insure that these critical vehicle systems receive the correct amount of properly treated fluid, automotive manufacturers employ a method called Evacuation and Fill. Due to their closed-loop design, many critical vehicle systems must be first exposed to vacuum prior to being flooded with fluid. Only after the evacuation and fill process is complete will the critical vehicle system be able to perform as specified. It has long been thought, but never proven, that humidity and entrenched fluid were major hindrances to the Evacuation and Fill process. Consequently, Ford Motor Company Advanced Manufacturing Technology Development, Sandalwood Enterprises, Kettering University, and Dominion Tool & Die conducted a detailed project on this subject.
Technical Paper

Acoustical Advantages of a New Polypropylene Absorbing Material

1999-05-17
1999-01-1669
Sound absorption is one way to control noise in automotive passenger compartments. Fibrous or porous materials absorb sound in a cavity by dissipating energy associated with a propagating sound wave. The objective of this study was to evaluate the acoustic performance of a cotton fiber absorbing material in comparison to a new polypropylene fibrous material, called ECOSORB ®. The acoustical evaluation was done using measurements of material properties along with sound pressure level from road testing of a fully-assembled vehicle. The new polypropylene fibrous material showed significant advantages over the cotton fiber materials in material properties testing and also in-vehicle measurements. In addition to the performance benefits, the polypropylene absorber provided weight savings over the cotton fiber material.
Technical Paper

A Photographic Investigation of Multi-Stage Fuel Injection in a Single Cylinder DI Diesel Engine

1999-05-03
1999-01-1501
Increasing concern about the impact of internal combustion engines on the environment has led to ever more stringent emission legislation, and the introduction of more sophisticated equipment to enable the requirements to be achieved. One way of improving the emissions from direct injection (DI) diesel engines is to use multi-stage fuel injection, and an investigation performed on such a system is reported in this paper. In this case, the multi-stage fuel injector caused an increase in the exhaust smoke at low load, and an in-cylinder photographic technique was used to examine why this occurred. A multi-stage fuel injector with a VCO nozzle was fitted to a small, high-speed, direct injection diesel engine fitted with a transparent piston for optical access. The combustion process was filmed using a high-speed 16 mm cine camera, and the fuel injection process was illuminated by a high power, copper-vapour laser.
Technical Paper

A Comparison of Gasoline Direct Injection and Port Fuel Injection Vehicles: Part II - Lubricant Oil Performance and Engine Wear

1999-05-03
1999-01-1499
Four 1998 Mitsubishi Carismas, two equipped with direct injection (GDI) and two with port fuel injection engines (PFI) were tested in a designed experiment to determine the effect of mileage accumulation cycle, engine type, fuel and lubricant type on engine wear and engine oil performance parameters. Fuel types were represented by an unadditised base fuel meeting EEC year 2000 specifications and the same base fuel plus synthetic deposit control additive packages. Crankcase oils were represented by two types (1) a 5W-30 API SJ/ILSAC GF-2 type engine oil and (2) a 10W-40 API SH/CF ACEA A3/ B3-96 engine oil. The program showed that specific selection of oil additive chemistry may reduce formation of intake valve deposits in GDI cars.. In general, G-DI engines produced more soot and more pentane insolubles and were found to be more prone to what appears to be soot induced wear than PFI engines.
Technical Paper

Alternative Fuel Vehicle Fleet Buyer's Guide

1999-05-03
1999-01-1510
Fleet managers need a tool to assist them in assessing their need to comply with EPAct and to provide them with the ability to obtain information that will allow them to make alternative fuel vehicle purchasing decisions. This paper will describe the Web-based tool that will inform a fleet manager, based on their geographic location, the type of fleet they own or operate, and the number and types of vehicles in their fleet, whether or not they need to meet the requirements of EPAct, and, if so, the percentage of new vehicle purchases needed to comply with the law. The tool provides detailed specifications on available OEM alternative fuel vehicles, including the purchase cost of the vehicles, fuel and fuel system characteristics, and incentives and rebates surrounding the purchase of each vehicle. The full set of federal, state, and local incentives is made available through the tool, as well as detailed access to refueling site and dealership locations.
Technical Paper

Effects of a Hybrid Fuel System with Diesel and Premixed DME/Methane Charge on Exhaust Emissions in a Small DI Diesel Engine

1999-05-03
1999-01-1509
Early stage combustion systems, with lean homogeneous charge compression ignition (HCCI), have been studied, with the intent to decrease the pollutant emission characteristics of DI diesel engines. Early stage combustion enables drastic reductions in both nitrogen oxides (NOx) and smoke emission, but the operating load range is restricted, due to combustion phenomena, such as unsteady combustion and knocking. In this study, we explored the possibility of broadening the operating load range in HCCI and reducing pollutant emissions using Dimethyl Ether (DME) fumigated through the intake pipe. However, the improvements in load range were found to be less than 0.1 MPa in brake mean effective pressure (BMEP), even when compression ratios were reduced and Methane with high octane number was mixed. Therefore, a DME premixed charge could be used only at light loads. At heavier loads a hybrid fuel system with a DME premixed charge and diesel fuel injection is necessary.
Technical Paper

Methylal and Methylal-Diesel Blended Fuels for Use in Compression-Ignition Engines

1999-05-03
1999-01-1508
“Gas-to-liquids” catalytic conversion technologies show promise for liberating stranded natural gas reserves and for achieving energy diversity worldwide. Some gas-to-liquids products are used as transportation fuels and as blendstocks for upgrading crude-derived fuels. Methylal (CH3-O-CH2-O-CH3), also known as dimethoxymethane or DMM, is a gas-to-liquid chemical that has been evaluated for use as a diesel fuel component. Methylal contains 42% oxygen by weight and is soluble in diesel fuel. The physical and chemical properties of neat methylal and for blends of methylal in conventional diesel fuel are presented. Methylal was found to be more volatile than diesel fuel, and special precautions for distribution and fuel tank storage are discussed. Steady state engine tests were also performed using an unmodified Cummins B5.9 turbocharged diesel engine to examine the effect of methylal blend concentration on performance and emissions.
Technical Paper

Experimental and Simulation Approaches to Understanding Soot Aggregation

1999-05-03
1999-01-1516
During 1998, the US Federal authority introduced a requirement for vehicles powered by heavy duty diesel engines that NOx emissions shall be less than 4 g/bhp.h. This represents a 20% reduction over current levels and has prompted significant further hardware changes. As a result of these increasingly tighter NOx emission constraints, soot loading of diesel engine lubricants - due to retarded fuel injection, is becoming an ever more significant issue in crankcase lubricant formulation. For this reason, increased understanding is required of the mechanism of soot particle aggregation and resultant aggregate morphology - together with the likely consequences for the performance of soot-laden lubricants, for viscosity increase, filter blocking, sludging and (directly or indirectly) - soot-induced wear. We describe here a combined experimental and simulation approach to screening formulated lubricants and characterising soot aggregate structures.
Technical Paper

Particulate Emissions from a Direct-Injection Spark-Ignition (DISI) Engine

1999-05-03
1999-01-1530
The numbers, sizes, and derived mass emissions of particles from a production DISI engine are examined over a range of engine operating conditions. Particles are sampled directly from the exhaust pipe using heated ejector pump diluters. The size distributions are measured using a scanning mobility particle sizer. The numbers and sizes of the emitted particles are reported for stratified versus homogeneous operation and as a function of fuel injection timing, spark timing, engine speed, and engine load. The principal finding is that particle number emissions increase by about a factor of 10 - 40 going from homogeneous to stratified charge operation. The particulate emissions exhibit a strong sensitivity to injection timing; generally particle number and volume concentrations increase steeply as the injection timing is retarded, except over a narrow portion of the range where the trend reverses.
Technical Paper

Engine-Out Emissions from a Direct-Injection Spark-Ignition (DISI) Engine

1999-05-03
1999-01-1529
The effects of operating parameters (speed, load, spark-timing, EGR, and end of fuel injection timing [EOI]) on engine-out, regulated (total HC, NOx, and CO) and speciated HC emissions have been investigated for a 1.83 L direct-injection, spark-ignition (DISI) engine. As the EOI is varied over the range from high to low stratification with other engine parameters held constant, the mole fractions of all regulated emissions vary sharply over relatively small (10-20 crank angle degrees [CAD]) changes in EOI, suggesting that emissions are very sensitive to the evaporation, mixing, and motion of the stratified fuel cloud prior to ignition. The contribution of unburned fuel to the HC emissions decreases while the olefinic partial oxidation products increase as the fuel stratification increases, increasing the smog reactivity of the HC in the exhaust gas by 25%.
Technical Paper

A Method to Measure Air Conditioning Refrigerant Contributions to Vehicle Evaporative Emissions (SHED Test)

1999-05-03
1999-01-1539
Although the intent of the SHED test (Sealed Housing for Evaporative Determination) is to measure evaporative fuel losses, the SHED sampling methodology in fact measures hydrocarbons from all vehicle and test equipment sources. Leakage of air conditioning (AC) refrigerant is one possible non-fuel source contributing to the SHED hydrocarbon measurement. This report describes a quick and relatively simple method to identify the contribution of AC refrigerant to the SHED analyzer reading. R134A (CH2FCF3), the hydrofluorocarbon refrigerant used in all current automotive AC systems, as well as its predecessor, the chlorofluorocarbon R12, can be detected using the gas chromatography methods currently in place at many emissions labs for the speciation of exhaust and evaporative hydrocarbon emissions.
Technical Paper

Application of Computational Fluid Dynamics for Flow Force Optimization of a High Pressure Fuel Injector Spill Valve

1999-05-03
1999-01-1537
Development of Caterpillar Fuel Systems' MEUI-B injector has involved application of Computational Fluid Dynamics (CFD) in order to improve performance of the high pressure spill valve. Initial performance bench testing with concept stage experimental injectors indicated that the chamber pressure was decaying at an unacceptably slow rate, and the valve demonstrated erratic behavior at some operating conditions. The slow pressure decay and inconsistent spill valve motion were believed to be caused by flow forces generated during the low lift portion of the spill valve opening event. This theory was pursued by utilizing CFD to design two valves for testing in the next phase of the injector development cycle: A baseline geometry, similar to the original concept injector valve, and a new design incorporating localized seat geometry changes for inducing flow force assisted valve opening.
Technical Paper

Shoebox Converter Design for Thinwall Ceramic Substrates

1999-05-03
1999-01-1542
Shoebox catalytic converter design to securely mount thinwall substrates with uniform mounting mat Gap Bulk Density (GBD) around the substrate is developed and validated. Computational Fluid Dynamic (CFD) analysis, using heat transfer predictions with and without chemical reaction, allows to carefully select the mounting mat material for the targeted shell skin temperature. CFD analysis enables to design the converter inlet and outlet cones to obtain uniform exhaust gas flow to achieve maximum converter performance and reduce mat erosion. Finite Element Analysis (FEA) is used to design and optimize manufacturing tool geometry and control process. FEA gives insight to simulate the canning process using displacement control to identify and optimize the closing speed and load to achieve uniform mat Gap Bulk Density between the shell and the substrate.
Technical Paper

Tailpipe Emissions Comparison Between Propane and Natural Gas Forklifts

2000-06-19
2000-01-1865
It is commonly stated that natural gas-fueled forklifts produce less emissions than propane-fueled forklifts. However, there is relatively little proof. This paper reports on a detailed comparative study at one plant in Edmonton, Canada where a fleet of forklift trucks is used for indoor material movement. (For convenience, the acronym NGV, ie. Natural Gas Vehicle is used to designate natural gas-fueled and LPG, ie. Liquified Petroleum Gas, is used to designate propane-fueled forklifts). Until recently the forklift trucks (of various ages) were LPG carburetted units with two-way catalytic converters. Prompted partially by worker health concerns, the forklifts were converted to fuel injected, closed-loop controlled NGV systems with three-way catalytic converters. The NGV-converted forklifts reduced emissions by 77% (NOX) and 76% (CO) when compared to just-tuned LPG forklifts.
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