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Technical Paper

Semi-Volatile Organic Compounds from a Combined Dual Port Injection/Direct-Injection Technology Light-Duty Gasoline Vehicle

2019-09-09
2019-24-0051
Gasoline direct injection (GDI) has changed the exhaust composition in comparison with the older port fuel injection (PFI) systems. More recently, light-duty vehicle engine manufactures have combined these two technologies to take advantage of the knock benefits and fuel economy of GDI with the low particulate emission of PFI. These dual injection strategy engines have made a change in the combustion emission composition produced by these engines. Understanding the impact of these changes is essential for automotive companies and aftertreatment developers. A novel sampling system was designed to sample the exhaust generated by a dual injection strategy gasoline vehicle using the United States Federal Test Procedure (FTP). This sampling system was capable of measuring the regulated emissions as well as collecting the entire exhaust from the vehicle for measuring unregulated emissions.
Technical Paper

Duct Shape Optimization Using Multi-Objective and Geometrically Constrained Adjoint Solver

2019-04-02
2019-01-0823
In the recent years, adjoint optimization has gained popularity in the automotive industry with its growing applications. Since its inclusion in the mainstream commercial CFD solvers and its continuously added capabilities over the years, its productive usage became readily available to many engineers who were previously limited to interfacing the customized adjoint source code with CFD solvers. The purpose of this work is to demonstrate using an adjoint solver a method to optimize duct shape that meets multiple design objectives simultaneously. To overcome one of the biggest challenges in the duct design, i.e. the severe packaging constraints, the method here uses geometrically constrained adjoint to ensure that the optimum shape always fits into the user-defined packaging space. In this work, adjoint solver and surface sensitivity calculations are used to develop the optimization method.
Technical Paper

Polycyclic Aromatic Hydrocarbons in Diesel Engine Exhaust Both with and without Aftertreatment

2018-09-10
2018-01-1812
Since the conception of the internal combustion engine, smoky and ill-smelling exhaust was prevalent. Over the last century, significant improvements have been made in improving combustion and in treating the exhaust to reduce these effects. One group of compounds typically found in exhaust, polycyclic aromatic hydrocarbons (PAH), usually occurs at very low concentrations in diesel engine exhaust. Some of these compounds are considered carcinogenic, and most are considered hazardous air pollutants (HAP). Many methods have been developed for sampling, handling, and analyzing PAH. For this study, an improved method for dilute exhaust sampling was selected for sampling the PAH in diesel engine exhaust. This sampling method was used during transient engine operation both with and without aftertreatment to show the effect of aftertreatment.
Technical Paper

Effect of Lubricant Oil on Particle Emissions from a Gasoline Direct Injection Light-Duty Vehicle

2018-09-10
2018-01-1708
Gasoline direction injection (GDI) engines have been widely used by light-duty vehicle manufacturers in recent years to meet stringent fuel economy and emissions standards. Particulate Matter (PM) mass emissions from current GDI engines are primarily composed of soot particles or black carbon with a small fraction (15% to 20%) of semi-volatile hydrocarbons generated from unburned/partially burned fuel and lubricating oil. Between 2017 and 2025, PM mass emissions regulations in the USA are expected to become progressively more stringent going down from current level of 6 mg/mile to 1 mg/mile in 2025. As PM emissions are reduced through soot reduction, lubricating oil derived semi-volatile PM is expected to become a bigger fraction of total PM mass emissions.
Technical Paper

Stress Analysis on the Single-Lap SPR- Adhesive Hybrid Joint

2018-04-03
2018-01-1445
Self-pierced rivet (SPR) and adhesive are two important joining technologies widely used in automobile industry, and they are often used together to form a hybrid joint. SPR and adhesives can often be used in close proximity in a component, leading to an interaction of the two joints. This interaction can influence the corrosion and noise, vibration and harshness (NVH) characteristics of the structure, as well as its strength and durability. In this paper, the stress distribution in an SPR-adhesive hybrid joint is evaluated by using the finite element method, and then compared with that in an adhesive joint. Results indicate that the stress concentrates at the edge of adhesive layer in hybrid joint and adhesive joint and around the rivet in an SPR joint. The effect of rivet is numerically investigated by either removing the rivet from the hybrid joint or changing the position of the rivet on the overlapping area.
Technical Paper

The Effect of Friction Modifiers and DI Package on Friction Reduction Potential of Next Generation Engine Oils: Part I Fresh Oils

2018-04-03
2018-01-0933
Friction reduction in lubricated components through engine oil formulations has been investigated in the present work. Three different DI packages in combination with one friction modifier were blended in SAE 5 W-20 and SAE 0 W-16 viscosity grades. The friction performance of these oils was compared with GF-5 SAE 5 W-20 oil. A motored cranktrain assembly has been used to evaluate these, in which friction mean effective pressure (FMEP) as a function of engine speeds at different lubricant temperatures is measured. Results show that the choice of DI package plays a significant role in friction reduction. Results obtained from the mini-traction machine (MTM2) provide detailed information on traction coefficient in boundary, mixed and elastohydrodynamic (EHD) lubrication regimes. It has been shown that the results from the cranktrain rig are fairly consistent with those found in MTM2 tests for all the lubricants tested.
Technical Paper

A Methodology of Real-World Fuel Consumption Estimation: Part 1. Drive Cycles

2018-04-03
2018-01-0644
To assess the fuel consumption of vehicles, three sets of input data are required; drive cycles, vehicle parameters, and environmental conditions. As the first part of a series of studies on real-world fuel consumption, this study focuses on the drive cycles. In principle, drive cycles should represent real-world usage. Some of them aim at a specific usage such as a city driving condition or an aggressive driving style. However, the definition of city or aggressive driving is very subjective and difficult to quantitatively correlate with the real-world usage. This study proposes a methodology to quantify the speed and dynamics of drive cycles, or vehicle speed traces in general, against the real-world usage. After reviewing parameter sets found in other studies, relative cubic speed (RCS) and positive kinetic energy (PKE) are selected to represent the speed and dynamics through energy flow balance at the wheels.
Technical Paper

Using Machine Learning to Guide Simulations Over Unique Samples from Trip Profiles

2018-04-03
2018-01-1202
Electric vehicles are highly sensitive to variations in environmental factors (like temperature, drive style, grade, etc.). The distribution of real-world range of electric vehicles due to these environmental factors is an important consideration in target setting. This distribution can be obtained by running several simulations of an electric vehicle for a number of high-frequency velocity, grade, and temperature real-world trip profiles. However, in order to speed up simulation time, a unique set of drive profiles that represent the entire real-world data set needs to be developed. In this study, we consider 40,000 unique velocity and grade profiles from various real-world applications in EU. We generate metadata that describes these profiles using trip descriptor variables. Due to the large number of descriptor variables when considering second order effects, we normalize each descriptor and use principal component analysis to reduce the dimensions of our dataset to six components.
Journal Article

Benefits of Pd Doped Zeolites for Cold Start HC/NOx Emission Reductions for Gasoline and E85 Fueled Vehicles

2018-04-03
2018-01-0948
In the development of HC traps (HCT) for reducing vehicle cold start hydrocarbon (HC)/nitrogen oxide (NOx) emissions, zeolite-based adsorbent materials were studied as key components for the capture and release of the main gasoline-type HC/NOx species in the vehicle exhaust gas. Typical zeolite materials capture and release certain HC and NOx species at low temperatures (<200°C), which is lower than the light-off temperature of a typical three-way catalyst (TWC) (≥250°C). Therefore, a zeolite alone is not effective in enhancing cold start HC/NOx emission control. We have found that a small amount of Pd (<0.5 wt%) dispersed in the zeolite (i.e., BEA) can significantly increase the conversion efficiency of certain HC/NOx species by increasing their release temperature. Pd was also found to modify the adsorption process from pure physisorption to chemisorption and may have played a role in the transformation of the adsorbed HCs to higher molecular weight species.
Journal Article

Passive Hydrocarbon Trap to Enable SULEV-30 Tailpipe Emissions from a Flex-Fuel Vehicle on E85 Fuel

2018-04-03
2018-01-0944
Future LEV-III tailpipe (TP) emission regulations pose an enormous challenge forcing the fleet average of light-duty vehicles produced in the 2025 model year to perform at the super ultralow emission vehicle (SULEV-30) certification levels (versus less than 20% produced today). To achieve SULEV-30, regulated TP emissions of non-methane organic gas (NMOG) hydrocarbons (HCs) and oxygenates plus oxides of nitrogen (NOx) must be below a combined 30 mg/mi (18.6 mg/km) standard as measured on the federal emissions certification cycle (FTP-75). However, when flex-fuel vehicles use E85 fuel instead of gasoline, NMOG emissions at cold start are nearly doubled, before the catalytic converter is active. Passive HC traps (HCTs) are a potential solution to reduce TP NMOG emissions. The conventional HCT design was modified by changing the zeolite chemistry so as to improve HC retention coupled with more efficient combustion during the desorption phase.
Journal Article

Tier 2 Test Fuel Impact to Tier 3 Aftertreatment Systems and Calibration Countermeasures

2018-04-03
2018-01-0941
During the course of emissions and fuel economy (FE) testing, vehicles that are calibrated to meet Tier 3 emissions requirements currently must demonstrate compliance on Tier 3 E10 fuel while maintaining emissions capability with Tier 2 E0 fuel used for FE label determination. Tier 3 emissions regulations prescribe lower sulfur E10 gasoline blends for the U.S. market. Tier 3 emissions test fuels specified by EPA are required to contain 9.54 volume % ethanol and 8-11 ppm sulfur content. EPA Tier 2 E0 test fuel has no ethanol and has nominal 30 ppm sulfur content. Under Tier 3 rules, Tier 2 E0 test fuel is still used to determine FE. Tier 3 calibrations can have difficulty meeting low Tier 3 emissions targets while testing with Tier 2 E0 fuel. Research has revealed that the primary cause of the high emissions is deactivation of the aftertreatment system due to sulfur accumulation on the catalysts.
Journal Article

A New Catalyzed HC Trap Technology that Enhances the Conversion of Gasoline Fuel Cold-Start Emissions

2018-04-03
2018-01-0938
Passive in-line catalyzed hydrocarbon (HC) traps have been used by some manufacturers in the automotive industry to reduce regulated tailpipe (TP) emissions of non-methane organic gas (NMOG) during engine cold-start conditions. However, most NMOG molecules produced during gasoline combustion are only weakly adsorbed via physisorption onto the zeolites typically used in a HC trap. As a consequence, NMOG desorption occurs at low temperatures resulting in the use of very high platinum group metal (PGM) loadings in an effort to combust NMOG before it escapes from a HC trap. In the current study, a 2.0 L direct-injection (DI) Ford Focus running on gasoline fuel was evaluated with full useful life aftertreatment where the underbody converter was either a three-way catalyst (TWC) or a HC trap. A new HC trap technology developed by Ford and Umicore demonstrated reduced TP NMOG emissions of 50% over the TWC-only system without any increase in oxides of oxygen (NOx) emissions.
Technical Paper

The Development of Low Temperature Three-Way Catalysts for High Efficiency Gasoline Engines of the Future: Part II

2018-04-03
2018-01-0939
It is anticipated that future gasoline engines will have improved mechanical efficiency and consequently lower exhaust temperatures at low load conditions, although the exhaust temperatures at high load conditions are expected to remain the same or even increase due to the increasing use of downsized turbocharged engines. In 2014, a collaborative project was initiated at Ford Motor Company, Oak Ridge National Lab, and the University of Michigan to develop three-way catalysts with improved performance at low temperatures while maintaining the durability of current TWCs. This project is funded by the U.S. Department of Energy and is intended to show progress toward the USDRIVE target of 90% conversion of hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) at 150 °C after high mileage aging. The testing protocols specified by the USDRIVE ACEC team for stoichiometric S-GDI engines were utilized during the evaluation of experimental catalysts at all three facilities.
Technical Paper

A Packaging Layout to Mitigate Crosstalk for SiC Devices

2018-04-03
2018-01-0462
SiC devices have inherent fast switching capabilities due to their superior material properties, and are considered potential candidates to replace Si devices for traction inverters in electrified vehicles in future. However, due to the comparatively low gate threshold voltage, SiC devices may encounter oscillatory false triggering especially during fast switching. This paper analyzed the causes of false triggering, and also studied the impact of a critical parasitic parameter - common source inductance. It is shown that crosstalk is the main cause for the false triggering in the case and some positive common source inductance help to mitigate the crosstalk issue. A packaging layout method is proposed to create the positive common source inductance through layout of control terminals / busbars, and/or the use of control terminal bonded wires at different height.
Technical Paper

Methodology for Determination and Optimization of Bolted Joints

2017-11-07
2017-36-0294
In order to optimize the development of bolted joints used to components attachments in the Sidemember of commercial vehicles, the joints development has become relevant to better definition of the fasteners size, eliminating overweight and avoiding under or super-sized. This paper presents a development sequential approach of bolted joints applied on commercial vehicles ensuring the correct specifications usage of the fasteners and the joint to keep their clamp force. The evaluations were conducted based on theoretical and practical aspects applied on products and in the definition of all elements contained in a joint. The calculation methodology was developed based on standardized bolts and forces generated through the reactions of the components required for each vehicle family.
Technical Paper

Development of a Commercial Truck Parabolic Leaf Spring Using CAE Simulation with Correlated Experimental Stress Analysis Results

2017-11-07
2017-36-0126
The development costs that new design requires are subject to everyday discussions and saving opportunities are mandatory. Using CAE to predict design changes can avoid excessive costs with prototypes parts, considering the high reliability those current mathematical models can provide. This paper presents the methodology used during the development of a parabolic leaf spring for the rear suspension of a commercial truck, considering mainly the parabolic profiles and stress distribution on the leaves, calculated using CAE software (ANSYS) and experimental tests to measure the actual stress on each leaf, certifying the correlation between computational calculations and real stress on the parts during bench and vehicle evaluations.
Technical Paper

Application of CAE (Computer Aided Engineering) Superelement Technique for NVH (Noise, Vibration and Harshness) Attributes on a Trimmed-Body Vehicle Structure in Order to Assist Supplier Commodity Development Based Also on NVH Requirements

2017-11-07
2017-36-0081
The business environment is ever changing, several innovations have allowed companies to transcend borderlines and become global entities. While the opportunities are numerous so are the challenges. In this fiercely competitive global marketplace, success requires companies to pay closer attention to supplier relations. The relationship between an automotive industry and its suppliers is an example of it, so the application of CAE (Computer Aided Engineering) superelement technique may improve, in terms of NVH (Noise, Vibration and Harshness), the vehicle development efficiency, without compromising confidentiality directives. Most of NVH requirements must be tracked through Transfer Functions (TFs) analyses at response points located on the Trimmed-Body Finite Element Model (FEM), as for example: Point Mobility, Vibration Transfer Function (VTF) and Acoustic Transfer Function (ATF).
Journal Article

The Influence of Fuel Cetane Number on Catalyst Light-Off Operation in a Modern Diesel Engine

2017-08-18
2017-01-9378
The design of modern diesel-powered vehicles involves optimization and balancing of trade-offs for fuel efficiency, emissions, and noise. To meet increasingly stringent emission regulations, diesel powertrains employ aftertreatment devices to control nitrogen oxides, hydrocarbons, carbon monoxide, and particulate matter emissions and use active exhaust warm-up strategies to ensure those devices are active as quickly as possible. A typical strategy for exhaust warm-up is to operate with retarded combustion phasing, limited by combustion stability and HC emissions. The amount of exhaust enthalpy available for catalyst light-off is limited by the extent to which combustion phasing can be retarded. Diesel cetane number (CN), a measure of fuel ignition quality, has an influence on combustion stability at retarded combustion phasing. Diesel fuel in the United States tends to have a lower CN (both minimum required and average in market) than other countries.
Technical Paper

Evolution of Engine Air Induction System Hydrocarbon Traps

2017-03-28
2017-01-1014
Engine air induction systems hydrocarbon trap (HC trap) designs to limit evaporative fuel emissions, have evolved over time. This paper discusses a range of HC traps that have evolved in engine air induction systems. (AIS) The early zeolite flow through HC trap utilized an exhaust catalyst technology internal stainless steel furnace brazed substrate coated with zeolite media. This HC trap was installed in the AIS clean air tube. This design was heavy, complicated, and expensive but met the urgency of the implementation of the new evaporative emissions regulation. The latest Ford Motor Company HC trap is a simple plastic tray containing activated carbon with breathable non-woven polyester cover. This design has been made common across multiple vehicle lines with planned production annual volume in the millions. The cost of the latest HC trap bypass design is approximately 5% of the original stainless steel zeolite flow through HC trap.
Technical Paper

Improving Multi-Voltage Electrical System Performance with Smart Step-Down Converters

2017-03-28
2017-01-1668
The demand for more features in a vehicle is growing at an extraordinary rate. This trend especially with emerging autonomous functions shows no sign of slowing. The energy requires to supply this ever growing system goes through multiple conversion, protection and other elements before it actually powers the loads. Considering the loss of each of these elements for a vehicle and multiplying the value by the total numbers of cars, underlines the need for an optimized electrical distribution system to power all loads efficiently. In this paper, Smart Step-Down Convertor is introduced as a power supply to power devices which operate at voltages below the power net voltage while protecting the power net and the devices against faults.
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