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Technical Paper

Neat Biodiesel Fuel Engine Tests and Preliminary Modelling

2007-04-16
2007-01-0616
Engine performance and emission comparisons were made between the use of 100% soy, Canola and yellow grease derived biodiesel fuels and an ultra-low sulphur diesel fuel in the oxygen deficient regions, i.e. full or high load engine operations. Exhaust gas recirculation (EGR) was extensively applied to initiate low temperature combustion. An intake throttling valve was implemented to increase the differential pressure between the intake and exhaust in order to increase and enhance the EGR. The intake temperature, pressure, and EGR levels were modulated to improve the engine fuel efficiency and exhaust emissions. Furthermore, a preliminary ignition delay correlation under the influence of EGR was developed. Preliminary low temperature combustion modelling of the biodiesel and diesel fuels was also conducted. The research intends to achieve simultaneous reductions of nitrogen oxides and soot emissions in modern production diesel engines when biodiesel is applied.
Technical Paper

A Comparison of the Effect of E85 vs. Gasoline on Exhaust System Surface Temperatures

2007-04-16
2007-01-1392
With concerns over increasing worldwide demand for gasoline and greenhouse gases, many automotive companies are increasing their product lineup of vehicles to include flex-fuel vehicles that are capable of operating on fuel blends ranging from 100% gasoline up to a blend of 15% gasoline/85% ethanol (E85). For the purpose of this paper, data was obtained that will enable an evaluation relating to the effect the use of E85 fuel has on exhaust system surface temperatures compared to that of regular unleaded gasoline while the vehicle undergoes a typical drive cycle. Three vehicles from three different automotive manufacturers were tested. The surface of the exhaust systems was instrumented with thermocouples at specific locations to monitor temperatures from the manifold to the catalytic converter outlet. The exhaust system surface temperatures were recorded during an operation cycle that included steady vehicle speed operation; cold start and idle and wide open throttle conditions.
Technical Paper

Simultaneous Real-Time Measurements of NO and NO2 in Medium Duty Diesel Truck Exhaust

2007-04-16
2007-01-1329
The goal of the present work was to investigate the ability of the SEMTECH®-D Portable Emissions Measurement System (PEMS) to provide simultaneous, accurate, real-time (1Hz) measurements of NO and NO2 in vehicle exhaust. Extensive chassis dynamometer laboratory evaluation studies of the SEMTECH® system were conducted. The instantaneous (1Hz) NOx emissions were measured using a conventional chemiluminescence analyzer (CLA) and were compared to the sum of the instantaneous NO and NO2 measurements from the SEMTECH®-D. The sum of the NO and NO2 emissions measured by the SEMTECH® were in excellent agreement (within 95% in most cases) with the total NOx measurements from the conventional CLA. During the laboratory evaluation studies, several Federal Test Procedure (FTP) drive cycles were conducted. Examples of the NO and NO2 concentration and mass emissions measured using the SEMTECH®-D are presented along with the corresponding SEMTECH®-D detection limits.
Technical Paper

Laboratory Studies and Mathematical Modeling of Urea SCR Catalyst Performance

2007-04-16
2007-01-1573
This paper presents the development of an analytical model that complements laboratory based experiments to provide a tool for Selective Catalyst Reduction (SCR) applications. The model calibration is based on measured data from NOx reduction performance tests as well as ammonia (NH3) adsorption/desorption tests over select SCR catalyst formulations in a laboratory flow reactor. Only base metal/zeolite SCR samples were evaluated. Limited validations are presented that show the model agrees well with vehicle data from Environmental Protection Agency Federal Test Procedure (EPA FTP) emission assessments. The model includes energy and mass balances, several different NH3 reactions with NOx, NH3 adsorption and desorption algorithms, and NH3 oxidation.
Technical Paper

The Influence of Ammonia Slip Catalysts on Ammonia, N2O and NOX Emissions for Diesel Engines

2007-04-16
2007-01-1572
The use of urea-based selective catalytic reduction (SCR) is a promising method for achieving U.S. Tier 2 diesel emission standards for NOx. To meet the Tier 2 standards for Particulate Matter (PM), a catalyzed diesel particulate filter (CDPF) will likely be present and any ammonia (NH3) that is not consumed over an SCR catalyst would pass over the CDPF to make nitrous oxide (N2O) emissions and/or oxides of nitrogen (NOx), or exit the exhaust system as NH3. N2O is undesirable due to its high greenhouse gas potential, while NOx production from the slipped NH3 would reduce overall system NOx conversion efficiency. This paper reviews certain conditions where NH3 slip past an SCR system may be a concern, looks at what would happen to this slipped NH3 over a CDPF, and evaluates the performance of various supplier NH3 slip catalysts under varied space velocities, temperatures and concentrations of NH3 and NOx.
Technical Paper

The Influence of Ammonia to NOX Ratio on SCR Performance

2007-04-16
2007-01-1581
It is likely that use of urea-based selective catalytic reduction (SCR) will be needed to meet U.S. Tier 2 diesel emission standards for oxides of nitrogen (NOx). The ideal ratio of ammonia (NH3) molecules to NOx molecules (known as alpha) is 1:1 based on urea consumption and having NH3 available for reaction of all of the exhaust NOx. However, SCR efficiency can be less than 100% at low temperatures in general, and at higher temperatures with high exhaust SCR catalyst space velocities. At the low temperatures where NOx conversion efficiency is low, it may be advantageous to reduce the alpha ratio to values less than one (less NH3 than is needed to convert 100% of the NOx emissions) to avoid NH3 slip. At higher space velocities and high temperatures, the NOx conversion efficiency may be higher with alpha ratios greater than 1. There is however concern that the additional NH3 will be slipped under these conditions.
Technical Paper

IMPACT Phase II - Study to Remove 25% of the Weight from a Pick-up Truck

2007-04-16
2007-01-1727
This paper describes a joint project between Ford, the American Iron & Steel Institute, the University of Louisville, and the U. S. Army to reduce the weight of a full size pick-up truck by 25%, while keeping incremental costs to a minimum. Several alternate technologies were evaluated for each system, subsystem, and component of the vehicle and based on analysis of all combinations of these technologies, the solution which yielded the best overall cost and weight balance, while meeting all of the functional requirements, was selected. The major focus of the project was to develop new steel architectures and materials, since this would assure the maintenance of the lowest possible cost, though the study was not restricted to steel alone. The project was successful in meeting all of its targets, and a vehicle was built to demonstrate the feasibility of the various concepts.
Technical Paper

Wheel Fight Objective Metric Development

2007-05-15
2007-01-2391
Wheel Fight is the undesirable rotational response of a vehicle's steering wheel due to road input at any or all of the road/wheel tire patches. The type of road input that will cause wheel fight comes in two forms: continuous rough road surfaces such as broken concrete or transient inputs such as pot-holes and tar strips. An objective method to quantify a vehicle's wheel fight sensitivity would be of great value to the vehicle development engineer. To that end, a study was conducted on Ford's Vehicle Vibration Simulator (VVS) to gather subjective responses and use those as a basis for correlation to an objective metric. One road surface known to induce wheel fight consists of using a rubber strip and driving over it while impacting only one side of the vehicle. Under this condition, steering wheel data was acquired on five different light trucks from which paired comparison studies were conducted.
Technical Paper

Effects of Fuel Volatility, Load, and Speed on HC Emissions Due to Piston Wetting

2001-05-07
2001-01-2024
Piston wetting can be isolated from the other sources of HC emissions from DISI engines by operating the engine predominantly on a gaseous fuel and using an injector probe to impact a small amount of liquid fuel on the piston top. This results in a marked increase in HC emissions. In a previous study, we used a variety of pure liquid hydrocarbon fuels to examine the influence of fuel volatility and structure on the HC emissions due to piston wetting. It was shown that the HC emissions correspond to the Leidenfrost effect: fuels with very low boiling points yield high HCs and those with a boiling point near or above the piston temperature produce much lower HCs. All of these prior tests of fuel effects were performed at a single operating condition: the Ford World Wide Mapping Point (WWMP). In the present study, the effects of load and engine speed are examined.
Technical Paper

An On-Board Reductant Delivery System for Diesel Aftertreatment

2001-09-24
2001-01-3622
It has become evident that almost all diesel aftertreatment devices dealing with NOx and particulate matter (PM) controls require the addition of one or more reducing agents (reductants), such as diesel fuel, ammonia, or aqueous urea to enhance their efficiency and durability. These reductants can be used to catalytically convert NOx to N2, to enrich the air fuel ratio (A/F), or to increase temperatures for regenerating PM filters or for de-sulfating NOx traps. A number of injection methods have been developed recently to provide easy reductant addition. However, many of them may be cumbersome, costly, or ineffective. This paper describes a new reductant delivery system, which appears to minimize these shortcomings. To be effective, the manner of reductant injection into the exhaust is critical. First, the reductant must be added quickly to accommodate the fast transient operations.
Technical Paper

Flow-Acoustic Coupling in Quarter-Wave Resonators Using Computational Fluid Dynamics

2001-04-30
2001-01-1430
Quarter-wave resonators are commonly used as acoustic silencers in automotive air induction systems. Similar closed side branches can also be formed in the idle air bypass, exhaust gas recirculation, and positive crankcase ventilation systems of engines. The presence of a mean flow across these side branches can lead to an interaction between the mean flow and the acoustic resonances of the side branch. At discrete flow conditions, this coupling between the flow and acoustic fields may produce high amplitude acoustic pressure pulsations. For the quarter-wave resonator, this interaction can turn the silencer into a noise generator, while for systems where a valve is located at the closed end of the side branch the large pressure pulsations can cause the valve to fail. This phenomenon is not limited to automotive applications, and also occurs in natural gas pipelines, aircraft, and numerous other internal and external flows.
Technical Paper

An Investigation of EGR Treatment on the Emission and Operating Characteristics of Modern Diesel Engines

2007-04-16
2007-01-1083
Tests are conducted to improve the use of exhaust gas recirculation on a single cylinder diesel engine with EGR stream treatment techniques that include intake heating, combustible substance oxidation, catalytic fuel reforming, and partial bypass-flow control. In parallel with the empirical work, theoretical modeling analyses are performed to investigate the effectiveness of the reforming process and the combined effects on the overall system efficiency. The research is aimed at stabilizing and expanding the limits of heavy EGR during steady and transient operations so that the individual limiting conditions of EGR can be better identified. Additionally, the heavy EGR is applied to enable in-cylinder low temperature combustion. The effectiveness of EGR treatment on engine emission and operating characteristics are therefore reported.
Technical Paper

Development of a New Oxygen Storage Model for SIMTWC

2007-04-16
2007-01-1081
The high conversion efficiency required by the modern three-way catalyst (TWC) is dependent on oxygen storage material functionality and capacity. To successfully model a TWC, it is critical that the oxygen storage function in the catalyst be adequately represented. The original oxygen storage model (a simple “bucket” model) included in one of Ford's TWC models, SIMTWC, was developed for vehicle programs meeting LEV emission standards. Application of SIMTWC to test data from vehicles targeting more stringent emission standards, such as ULEV and PZEV, revealed limitations in the accuracy of the original bucket model. To address these limitations, an improved kinetic model of oxygen storage is being developed. This new model is more kinetically-detailed than the old model.
Technical Paper

Low Volatility ZDDP Technology: Part 2 - Exhaust Catalysts Performance in Field Applications

2007-10-29
2007-01-4107
Phosphorus is known to reduce effectiveness of the three-way catalysts (TWC) commonly used by automotive OEMs. This phenomenon is referred to as catalyst deactivation. The process occurs as zinc dialkyldithiophosphate (ZDDP) decomposes in an engine creating many phosphorus species, which eventually interact with the active sites of exhaust catalysts. This phosphorous comes from both oil consumption and volatilization. Novel low-volatility ZDDP is designed in such a way that the amounts of volatile phosphorus species are significantly reduced while their antiwear and antioxidant performances are maintained. A recent field trial conducted in New York City taxi cabs provided two sets of “aged” catalysts that had been exposed to GF-4-type formulations. The trial compared fluids formulated with conventional and low-volatility ZDDPs. Results of field test examination were reported in an earlier paper (1).
Technical Paper

Engineering the Ford H2 IC Engine Powered E-450 Shuttle Bus

2007-10-29
2007-01-4095
As a part of a continuous research and innovation effort, Ford Motor Company has been evaluating hydrogen since 1997 as an alternative fuel option for vehicles with internal combustion engines. Hydrogen fuel is attractive in that it is the cleanest fuel. Hydrogen, when used in an internal combustion engine, produces an exhaust emission consisting mainly of water vapor, with no carbon dioxide and trace amounts of other regulated pollutants. Hydrogen can be produced from renewable sources which will help reduce the dependence on foreign oil. The implementation of the hydrogen powered IC engine is seen as a strategy to help transition from a petroleum economy to a hydrogen economy and drive development of hydrogen storage, fueling infrastructure and other hydrogen related technologies.
Technical Paper

The Design for Six Sigma Approach for the Development of a Carbon Canister for Tier II, LEV II and PZEV Emission Levels

2007-04-16
2007-01-1090
Global concerns involving smog, ozone formation, carcinogens and greenhouse gases have produced increasingly stringent governmental emission regulations worldwide. In the United States, the Environmental Protection Agency (EPA) introduced Tier II emissions regulations and the California Air Resources Board (CARB) established Low Emission Vehicles (LEV II) and Partial Zero Emission Vehicles (PZEV) legislation. These initiatives have created the most stringent emissions regulations to date. Vehicle manufacturers have had to improve their evaporative emission control systems to comply with these standards. The evaporative emission control system is engineered to protect our environment from fuel vapor emissions. The carbon canister is the most important component of the evaporative emissions system due to its ability to capture fuel vapors continuously during the life of the vehicle. Ford Motor Company redesigned its carbon canisters after utilizing Experimental Design techniques.
Technical Paper

Fuel Economy Improvement Through Frictional Loss Reduction in Light Duty Truck Rear Axle

2002-10-21
2002-01-2821
In an effort to improve fuel economy for light duty trucks, an initiative was undertaken to reduce frictional losses in rear axle through use of low friction lubricants and novel surface finish on gears while maintaining durability. This paper describes the effect of rear axle lubricants on fuel economy. A laboratory rig was set up using a full size pick-up truck rear axle to measure axle efficiency and lubricant temperature with various SAE 75W-90 and SAE 75W-140 viscosity grade lubricants. Traction coefficients of lubricants were also measured at various temperatures using a laboratory ball and disk contact geometry. An improvement in axle efficiency up to 4.3% was observed over current Ford factory fill SAE 75W-140 lubricant depending on speed, torque and the type of lubricant used. The temperature of the lubricants was also lower than that with the current factory fill. This is important for maintaining bearing life and overall durability of the rear axle.
Technical Paper

Increasing Torque Output from a Turbodiesel with Camless Valvetrain

2002-03-04
2002-01-1108
In recent years sales of diesel-powered cars and trucks have increased dramatically worldwide. The efforts to raise specific power of diesel engines to allow for smaller and more efficient powertrains should include variable valvetrain technology. Some benefits that might become available with application of camshaft-based variable-valve mechanisms have been studied in [1]. Significant progress has also been reported in the development of camless actuation mechanisms [2, 3]. To fully evaluate the torque improvement opportunities for light duty diesel, the authors have assumed that a camless valvetrain will become available in the future. This will provide the ultimate flexibility to choose timing and duration of valve events to maximize full load torque. Simulation results revealed potential for a substantial increase in engine torque by optimizing the intake and exhaust valve timing together with turbocharger operation.
Technical Paper

Effects of Engine Oil Formulation Variables on Exhaust Emissions in Taxi Fleet Service

2002-10-21
2002-01-2680
The relationship between engine oil formulations and catalyst performance was investigated by comparatively testing five engine oils. In addition to one baseline production oil with a calcium plus magnesium detergent system, the remaining four oils were specifically formulated with different additive combinations including: one worst case with no detergent and production level zinc dialkyldithiophosphate (ZDTP), one with calcium-only detergent and two best cases with zero phosphorus. Emissions performance, phosphorus loss from the engine oil, phosphorus-capture on the catalyst and engine wear were evaluated after accumulating 100,000 miles of taxi service in twenty vehicles. The intent of this comparative study was to identify relative trends.
Technical Paper

Fuel-Air Mixing Homogeneity and Performance Improvements of a Stratified-Charge DISI Combustion System

2002-10-21
2002-01-2656
A CFD based design optimization methodology was developed and adopted to the development of a stratified-charge direct-injection spark ignition (DISI) combustion system. Two key important issues for homogeneous charge operation, volumetric efficiency and mixing homogeneity, are addressed. The intake port is optimized for improved volumetric efficiency with a CFD based numerical optimization tool. It is found that insufficient fuel-air mixing is the root cause for the low rated power of most DISI engines. The fuel-air mixing in-homogeneity is due to the interaction between intake flow and injected fuel spray. An injector mask design was proposed to alleviate such interaction, then to improve air-fuel mixture homogeneity. It was then confirmed with dynamometer testing that the optimized design improved engine output and at the same time had lower soot and CO emissions.
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