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Technical Paper

A New Test for Catalyst Oxygen Storage Which Correlates with Catalyst Performance on the Vehicle

A new laboratory test for measuring catalyst oxygen storage capacity has been developed. The test accurately predicts catalyst performance on the vehicle during transient A/F excursions and correlates well with vehicle CO and Nox tailpipe emissions. The test was subsequently used to facilitate improved oxygen storage capacity for new Pd-only washcoat formulations.
Technical Paper

Fuel Structure and the Nature of Engine-Out Emissions

For several years, a single-cylinder, spark-ignited engine without catalyst has been operated at Ford on single-component fuels that are constituents of gasoline as well as on simple fuel mixtures. This paper presents a review of these experiments as well as others pertinent to understanding hydrocarbon emissions. The engine was run at four steady-state conditions which are typical of normal operation. The fuel structure and the engine operating conditions affected both the total HC emissions and the reactivity of these emissions for forming photochemical smog in the atmosphere. These experiments identified major precursor species of the toxic HC emissions benzene and 1,3-butadiene to be alkylated benzenes and either straight chain terminal olefins or cyclic alkanes, respectively. In new data presented, the primary exhaust hydrocarbon species from MTBE combustion is identified as isobutene.
Technical Paper

A Comparison of the Emissions from a Vehicle in Both Normal and Selected Malfunctioning Operation Modes

A 1990 Ford Taurus operated on reformulated gasoline was tested under three modes of malfunction: disabled heated exhaust gas oxygen (HEGO) sensor, inactive catalytic converter, and controlled misfire. The vehicle was run for four U.S. EPA UDDS driving schedule (FTP-75) tests at each of the malfunction conditions, as well as under normal operating conditions. An extensive set of emissions data were collected. In addition to the regulated emissions (HC, CO, and NOx), a detailed chemical analysis was carried out to determine the gas- and particle-phase non-regulated emissions. The effect of vehicle malfunction on gas phase emissions was significantly greater than it was on particle phase emissions. For example, CO emissions ranged from 2.57 g/mi (normal operation) to 34.77 g/mi (disable HEGO). Total HCs varied from 0.22 g/mi (normal operation) to 2.21 g/mi (blank catalyst). Emissions of air toxics (1,3-butadiene, benzene, acetaldehyde, and formaldehyde) were also significantly effected.
Technical Paper

Commercial Van Diesel Idle Sound Quality

The customer's perception of diesel sounds is receiving more attention since diesel engines are being used more frequently in recent years. This paper summarizes the results of a study investigating the sound quality of diesel idle sounds in eight vans and light trucks. Subjective evaluations were conducted both in the US and the UK so that a comparison could be made. Paired comparison of annoyance and semantic differential subjective evaluation techniques were used. Correlation analysis was applied to the subjective evaluation results to determine annoying characteristics. Subjective results indicated that most annoyance rankings were similar for both the US and UK participants, with some specific differences. Correlation of objective measures to annoyance indicated a high correlation to ISO 532B loudness, dBA and kurtosis in the 1.4 kHz to 4 kHz range (aimed at quantifying the impulsiveness perception).
Technical Paper

High Frequency NVH Analysis of Full Size Pickups Using “SEAM”

The recent surveys of customer satisfaction regarding full size pickup trucks have created new mandates in performance of such vehicles. The customers for this class of vehicles demand new frontiers in attributes such as NVH, ride and handling performance that previously only belonged to the luxury passenger cars. The full size pickup truck in question must retain a tough image and be as durable as the previous generation truck that it replaces. But it also needs to be user friendly in order for one to drive it like an every day passenger car on a daily basis. The challenge is to design for the NVH performance that matches and surpasses many well behaved and “good” NVH passenger cars without any compromise in durability performance. An NVH 7-8 subjective rating performance is targeted for the design of full size pickup truck during vehicle operation.
Technical Paper

Development of the Ford QVM CNG Bi-Fuel 4.9L F-Series Pickup Truck

A bi-fuel (Compressed Natural Gas [CNG] and gasoline) pickup truck has been developed using the Ford Alternative Fuel Qualified Vehicle Modifier (QVM) process. The base vehicle's 4.9L engine has been specially modified for improved durability on gaseous fuels. The base vehicle's configuration has been designed for conversion to bi-fuel CNG operation. A complete CNG fuel system has been designed and qualified, including fuel tanks, fuel system, and electrical interface. The completed vehicle has been safety and emission certified, demonstrating CARB Low Emission Vehicle (LEV) emissions in MY95. This paper details the design objectives, development process, CNG components, and integration of the two fuel systems.
Technical Paper

Emissions from Diesel Vehicles with and without Lean NOx and Oxidation Catalysts and Particulate Traps

The regulated and non-regulated emissions of a current diesel passenger car and two light-duty diesel trucks with catalysts and particulate traps were measured to better understand the effects of aftertreatment devises on the environment. The passenger car, a 1.8 L IDI TC Sierra, was tested both with and without three different diesel oxidation catalysts (DOC) and with two fuel sulfur levels, 0 and 0.05 wt%. One light-duty truck, a 2.5 L DI NA Transit, was tested on one fuel, 0.05 wt% sulfur, with and without three different particulate trap/regeneration systems and with and without a urea lean NOx catalyst (LNC) system. A second similar Transit was tested on the 0.05 wt% sulfur fuel with an electrically regenerated trap system. The results are compared to each other, regulated emission standards, and to emissions from gasoline vehicles.
Technical Paper

An Urea Lean NOx Catalyst System for Light Duty Diesel Vehicles

Future European air quality standards for light duty diesel vehicles will include stringent NOx emission regulations. In order to meet these regulations, a lean NOx catalyst system may be necessary. Since the catalytic removal of NOx is very difficult with the large concentration of oxygen present in diesel exhaust, a reductant is usually added to the exhaust to increase the NOx conversion. This paper describes a lean NOx catalyst system for a Transit light-duty truck which uses a reductant solution of urea in water. In this work, a microprocessor was used to vary the amount of the reductant injected depending on the operating conditions of a 2,5 L naturally aspirated HSDI engine. The NOx conversions were 60% and 80% on the current European driving cycle and the U.S. FTP cycles, respectively. Data on the emissions of HC, CO, NOx, particulate mass and composition, individual HC species, aldehydes, PAH and most HC species were evaluated.
Technical Paper

Calculating the Rate of Exothermic Energy Release for Catalytic Converter Efficiency Monitoring

This paper reports on the development of a new methodology for OBD-II catalyst efficiency monitoring. Temperature measurements taken from the center of the catalyst substrate or near the exterior surface of the catalyst brick were used in conjunction with macroscopic energy balances to calculate the instantaneous rate of exothermic energy generation within the catalyst. The total calculated rate of exothermic energy release over the FTP test cycle was within 10% of the actual or theoretical value and provided a good indicator of catalyst light-off for a variety of aged catalytic converters. Normalization of the rate of exothermic energy release in the front section of the converter by the mass flow rate of air inducted through the engine was found to provide a simple yet practical means of monitoring the converter under both FTP and varying types of road driving.
Technical Paper

Some Phenomena Which Control Sulfuric Acid Emission from Automotive Catalysts

With the use of a simulated exhaust system, the sulfuric acid and sulfur dioxide emission from a monolith noble-metal oxidation catalyst (Engelhard IIB) is measured. It was found that the storage rate of sulfur onto an initially sulfur-free catalyst decreases to a few percent of the sulfur rejection rate within 3-4 h. The amount of sulfur on the catalyst when the catalyst is in equilibrium with 20 ppm sulfur in the gas phase varies between 0.3 weight percent of the catalyst at about 400°C to 0.1 weight percent at 600°C. The sulfur can readily desorb from the catalyst if the gas phase sulfur content is lowered or if the catalyst temperature is increased. It was found that the conversion of sulfur dioxide to sulfuric acid reaches thermodynamic equilibrium at temperatures of 400-500°C and space velocities of 30,000 h-1. These conditions correspond approximately to a small V8 engine at 20 mph cruise.
Technical Paper

Characterization of Phosphates Found in Vehicle-Aged Exhaust Gas Catalysts: A Raman Study

Phosphorus contamination from engine oil additives has been associated with reduced performance of vehicle-aged exhaust gas catalysts. Identifying phosphorus species on aged catalysts is important for understanding the reasons for catalytic performance degradation. However, phosphorus is present only in small quantities, which makes its detection with bulk analytical techniques difficult. Raman microscopy probes small regions (a few microns in diameter) of a sample, and can detect both crystalline and amorphous materials. It is thus ideal for characterizing phosphates that may have limited distribution in a catalyst. However, suitable Raman spectra for mixed-metal phosphates that might be expected to be present in contaminated catalysts are not generally available.
Technical Paper

Characterization of Automotive Catalysts Exposed to the Fuel Additive MMT

A series of in-use catalysts having mileage of 22,000 to 43,000 miles was characterized to determine the effect of the fuel additive MMT. The analytical techniques included visual examination, x-ray fluorescence, x-ray diffraction, optical microscopy, scanning electron microscopy, and electron raicroprobe. In addition, catalyst activity was measured and compared to the catalyst activity from a pulsator aged catalyst without the MMT additive in the feed gas composition. Characterization results show a significantly thick layer (5-20 microns) covering the surface of the catalysts which results in the increase of mass transfer resistance. Steady state R and light-off measurements indicated catalyst efficiency is also significantly reduced as exposure to MMT is increased.
Technical Paper

Frame Beaming, Fifth Wheel Location — Special Body Mounting and Loading Problems

Discussion of four factors pertinent to any overall ride evaluation. These factors are frame beaming, fifth wheel location, special body mountings, and variable loading conditions on tandem truck and tractor ride. The methodology for measuring the characteristics of these factors is reviewed and practical solutions for improved ride are given.
Technical Paper

New Ford Midrange Diesel Trucks

When Ford decided to offer a midrange diesel engine family in medium trucks, it was recognized that the power-train had to be considered as a complete system in order to assure optimum compatibility. This paper describes how program objectives were established and the necessary validation programs for the truck, engine, and the chassis were conducted.
Technical Paper

An Objective Approach to Highway Truck Frame Design

The design requirements for the frame as a load carrying member are discussed in relationship to a highway truck and its basic vehicle package. The theoretical and experimental procedures are given in detail to demonstrate the techniques for frame design. The features of a method to laboratory test a frame with correlation to service miles is discussed.
Technical Paper

Research Application of DFSS: Study of the Impact of Accelerated Aging and Recovery on Low-Rh Three-Way Catalyst Activity for Catalyst Monitoring

Robust on-board diagnosis of emission catalyst performance requires the development of artificially damaged "threshold" catalysts that accurately mimic the performance of damaged catalysts in customer use. The threshold catalysts are used by emissions calibrators to determine fore-aft exhaust oxygen sensor responses that indicate catalyst failure. Rather than rely on traditional trial-and-error processes to generate threshold catalysts, we have used a DFSS (Design For Six-Sigma) approach that explores, at a research level, the relationship between oxygen storage capacity (OSC) of the catalyst (i.e., the fundamental property dictating the response of the aft oxygen sensor) and key process input variables: high-temperature exposure, phosphorus poisoning, and catalyst "recovery."
Technical Paper

A Linear Catalyst Temperature Sensor for Exhaust Gas Ignition (EGI) and On Board Diagnostics of Misfire and Catalyst Efficiency

Afterburning of a rich exhaust/air mixture ahead of the catalyst has been shown in earlier papers to offer an effective means of achieving catalyst light-off in very short times. Protection of the catalyst from overheating is an important aspect of systems using EGI, and on board diagnostics will be required to check for proper function of EGI. In this paper, some options for these requirements are discussed, using a high temperature linear thermistor.
Technical Paper

Impact of Computer Aided Engineering on Ford Light Truck Cooling Design and Development Processes

This paper presents the benefits of following a disciplined thermal management process during the design and development of Ford Light Truck engine cooling systems. The thermal management process described has evolved through the increased use of Computer Aided Engineering (CAE) tools. The primary CAE tool used is a numerical simulation technique within the field of Computational Fluid Dynamics (CFD). The paper discusses the need to establish a heat management team, develop a heat management model, construct a three dimensional CFD model to simulate the thermal environment of the engine cooling system, and presents CFD modeling examples of Ford Light Trucks with engine driven cooling fans.
Technical Paper

A Study on Ride-Down Efficiency and Occupant Responses in High Speed Crash Tests

In vehicle crash tests, an unbelted occupant's kinetic energy is absorbed by the restraints such as an air bag and/or knee bolster and by the vehicle structure during occupant ride-down with the deforming structure. Both the restraint energy absorbed by the restraints and the ride-down energy absorbed by the structure through restraint coupling were studied in time and displacement domains using crash test data and a simple vehicle-occupant model. Using the vehicle and occupant accelerometers and/or load cell data from the 31 mph barrier crash tests, the restraint and ride-down energy components were computed for the lower extremity, such as the femur, for the light truck and passenger car respectively.
Technical Paper

Vehicle Closure Sound Quality

This paper describes an investigation into the sound quality of passenger car and light truck closure sounds. The closure sound events that were studied included side doors, hoods, trunklids, sliding doors, tailgates, liftgates, and fuel filler doors. Binaural recordings were made of the closure sounds and presented to evaluators. Both paired comparison of preference and semantic differential techniques were used to subjectively quantify the sound quality of the acoustic events. Major psychoacoustic characteristics were identified, and objective measures were then derived that were correlated to the subjective evaluation results. Regression analysis was used to formulate models which can quantify customers perceptions of the sounds based on the objectively derived parameters. Many times it was found that the peak loudness level was a primary factor affecting the subjective impression of component quality.