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Technical Paper

Rapid Fuel Injector Re-Pressurization

2007-04-16
2007-01-1075
A fuel system design objective is to have the fuel injection pressure at target pressure by the time of the first injection. In most cases, a vapor and air space forms in the highest and hottest part of the fuel injector supply as the fuel system cools following engine-off. Upon key-on, the fuel pump needs to collapse the fuel vapor and compress any air before fuel pressure can build thus delaying fuel injector re-pressurization. An inventive solution to speed re-pressurization is described. It effectively eliminates the need to collapse the fuel vapor and compress any air in the first few tenths of seconds of fuel injection re-pressurization. The factors that affect fuel injection re-pressurization time are discussed.
Technical Paper

Steering Grunt Noise Robustness Improvement

2009-05-19
2009-01-2095
Grunt is a structure-born noise caused by resonance of the steering gear torsion bar (T-bar) in an HPAS (Hydraulic Power Assist Steering) system. The goal of this work was to develop techniques to quantify and predict grunt in a RV (rotary valve) steering gear system. First, vehicle testing was used to identify an objective metric for grunt: y = dynamic pressure in the return line. Then, a computer simulation was developed to predict y as a function of two known control factors. The simulation results were correlated to measurements on a test vehicle. Finally, the simulation was expanded to include two additional control factors, and grunt predictions were demonstrated on a different test vehicle.
Technical Paper

A New Analysis Method for Accurate Accounting of IC Engine Pumping Work and Indicated Work

2004-03-08
2004-01-1262
In order to improve fuel economy, engine manufacturers are investigating various technologies that reduce pumping work in spark ignition engines. Current cylinder pressure analysis methods do not allow valid comparison of pumping work reduction strategies. Existing methods neglect valve timing effects which occur during the expansion and compression strokes, but are actually part of the gas exchange process. These additional pumping work contributions become more significant when evaluating non-standard valve timing concepts. This paper outlines a new analysis method for calculating the pumping work and indicated work of a 4-stroke internal combustion engine. Corrections to PMEP and IMEP are introduced which allow the valid comparison of pumping work and indicated efficiency between engines with different pumping work reduction strategies.
Technical Paper

Verification of Accelerated PM Loading for DPF Qualification Studies

2009-04-20
2009-01-1089
High gas prices combined with demand for improved fuel economy have prompted increased interest in diesel engine applications for both light-duty and heavy-duty vehicles. The development of aftertreatment systems for these vehicles requires significant investments of capital and time. A reliable and robust qualification testing procedure will allow for more rapid development with lower associated costs. Qualification testing for DPFs has its basis in methods similar to DOCs but also incorporates a PM loading method and regeneration testing of loaded samples. This paper examines the effects of accelerated loading using a PM generator and compares PM generator loaded DPFs to engine dynamometer loaded samples. DPFs were evaluated based on pressure drop and regeneration performance for samples loaded slowly and for samples loaded under accelerated conditions. A regeneration reactor was designed and built to help evaluate the DPFs loaded using the PM generator and an engine dynamometer.
Journal Article

Drawbead Restraining Force Modeling: Nonlinear Friction

2009-04-20
2009-01-1391
A detailed investigation of influence of friction on drawbead restraining force modeling is presented in this paper. It is motivated by the need to accurately correlate line bead strengths, which are usually the output of an optimized draw development for controlling materials flow and achieving desired formability, and the physical drawbead geometries required for die face engineering. A plane-strain drawbead model with linear Coulomb friction is first established and the restraining forces corresponding to a range of bead penetration depths are obtained. The comparison of the simulation results with experimental data indicates that, while a larger Coefficient of Friction (COF) has better correlation for smaller bead penetrations and smaller COF does better for deeper bead penetrations, no single COF matches satisfactorily for overall range of bead penetration depths.
Technical Paper

Oil Migration on Sheet Steels and the Effect on Performance in Metal Stamping

1999-03-01
1999-01-0682
Mill oils and prelubes are applied by the steel producer to prevent corrosion and to enhance formability. During coiling, shipping, and storage the lubricant migrates due to pressure and gravity. The redistribution of the lubricant results in widely varying lubricant weights. The move to reduce and eliminate press-applied lubricants has lead to concerns that the variation in lubricant weight as a result of this migration would adversely affect press performance. The Drawbead Simulator (DBS) and Twist Compression Test (TCT) were used to evaluate friction response of electrogalvanized and galvanneal sheet to varying lubricant weight. Results showed the electrogalvanized sheet was sensitive to lubricant type while the galvanneal sheet was sensitive to the amount of lubricant.
Technical Paper

Gasoline Particulate Filter Efficiency and Backpressure at Very Low Mileage

2018-04-03
2018-01-1259
The need for gasoline particulate filter (GPF) technology is expected to grow with increasingly tight particle emissions standards being implemented in US, EU, China and elsewhere. Derived from the successful experience with diesel particulate filters (DPF), GPFs adopted the characteristic alternately plugged honeycomb structure that provides a large area of porous cordierite wall for filtering particles with minimal additional backpressure. However, unlike DPFs, continuous soot regeneration in GPFs makes it difficult to grow and sustain the soot cake on the filter wall that gives DPFs their high filtration efficiency. Therefore, filtration performance of low mileage GPFs relies heavily on the porous structure of filter media, which depends on both the substrate and the applied washcoat. In this work, a blank, two fresh washcoated filters and two washcoated filters with 3000 km mileage accumulation were characterized to compare their filtration performance.
Technical Paper

Intake Oxygen Sensor for EGR Measurement

2016-04-05
2016-01-1070
Traditional EGR measurement systems using delta pressure over a fixed orifice such as a DPFE sensor (Delta Pressure Feedback for EGR), have limitations in the ability to measure EGR accurately. Also, the pressure drop that results from the orifice may not be acceptable in some applications. To measure the EGR accurately and without any pressure loss, a new measurement system was developed that uses an oxygen sensor in the intake air. In this paper, the technology of using an oxygen sensor to measure the EGR concentration is discussed. The paper details the EGR measurement principle with an oxygen sensor and the associated mathematical relations of translating the oxygen measurement to EGR measurement. Factors affecting the EGR measurement such as the air/fuel ratio of the EGR, intake air pressure, and diffusion effects of the EGR constituents are discussed in detail. Compensation mechanisms are explained and associated results shown.
Technical Paper

Model Based Engine-Off Natural Vacuum Leak Detection Monitor

2017-03-28
2017-01-1020
Engine-Off Natural Vacuum (EONV) principles based leak detection monitors are designed to determine the presence of a small leak in the fuel tank system. It was introduced to address the ever more stringent emission requirement (currently at 0.02”) for gasoline engine equipped vehicles as proposed by the Environmental Protection Agency (EPA) and California Air Resources Board (CARB) in the United States [2, 3]. Other environmental protection agencies including the ones in EU and China will be adopting similar regulations in the near future. Due to its sensitivity to known noise factors such as the ambient temperature, barometric pressure, drive pattern and parking angle, it has been historically a lower performing monitor that is susceptible to warranty cost or even voluntary recalls. The proposed new model based monitor utilizes production pressure signal and newly instrumented temperature sensors [15].
Technical Paper

Control Strategies for Gasoline Particulate Filters

2017-03-28
2017-01-0931
While not commonly in production today, Gasoline Particulate Filters (GPFs) are likely to see widespread deployment to meet stringent EU6.2 and China particulate number (PN) standards. In many ways the operating conditions for GPFs are orthogonal to those of their diesel counterparts, and this leads to different and interesting requirements for the control strategy. We will present some generic system architectures for exhaust systems containing a GPF and will lay out an architecture for the GPF control strategy components which include: regeneration assist feature, soot estimation algorithm, GPF protection. The regeneration assist feature uses spark retard to increase exhaust temperature. The soot estimation algorithm describes how we can estimate soot from an open loop model or from a normalized pressure metric. The GPF protection feature controls oxygen flow to limit the soot burn rate. We will show validation data of the control strategy under different operating conditions.
Technical Paper

Characterization of Crankcase Pressure Variation during the Engine Cycle of an Internal Combustion Engine

2017-03-28
2017-01-1088
High frequency variations in crankcase pressure have been observed in Inline-four cylinder (I4) engines and an understanding of the causes, frequency and magnitude of these variations is helpful in the design and effective operation of various engine systems. This paper shows through a review and explanation of the physics related to engine operation followed by comparison to measured vehicle data, the relationship between crankcase volume throughout the engine cycle and the observed pressure fluctuations. It is demonstrated that for a known or proposed engine design, through knowledge of the key engine design parameters, the frequency and amplitude of the cyclic variation in crankcase pressure can be predicted and thus utilized in the design of other engine systems.
Technical Paper

An Indirect Tire Health Monitoring System Using On-board Motion Sensors

2017-03-28
2017-01-1626
This paper proposes a method to make diagnostic/prognostic judgment about the health of a tire, in term of its wear, using existing on-board sensor signals. The approach focuses on using an estimate of the effective rolling radius (ERR) for individual tires as one of the main diagnostic/prognostic means and it determines if a tire has significant wear and how long it can be safely driven before tire rotation or tire replacement are required. The ERR is determined from the combination of wheel speed sensor (WSS), Global Positioning sensor (GPS), the other motion sensor signals, together with the radius kinematic model of a rolling tire. The ERR estimation fits the relevant signals to a linear model and utilizes the relationship revealed in the magic formula tire model. The ERR can then be related to multiple sources of uncertainties such as the tire inflation pressure, tire loading changes, and tire wear.
Technical Paper

Driver Identification Using Vehicle Telematics Data

2017-03-28
2017-01-1372
Increasing number of vehicles are equipped with telematics devices and are able to transmit vehicle CAN bus information remotely. This paper examines the possibility of identifying individual drivers from their driving signatures embedded in these telematics data. The vehicle telematics data used in this study were collected from a small fleet of 30 Ford Fiesta vehicles driven by 30 volunteer drivers over 15 days of real-world driving in London, UK. The collected CAN signals included vehicle speed, accelerator pedal position, brake pedal pressure, steering wheel angle, gear position, and engine RPM. These signals were collected at approximately 5Hz frequency and transmitted to the cloud for offline driver identification modeling. A list of driving metrics was developed to quantify driver behaviors, such as mean brake pedal pressure and longitudinal jerk. Random Forest (RF) was used to predict driver IDs based on the developed driving metrics.
Technical Paper

Investigation of Flow Conditions and Tumble near the Spark Plug in a DI Optical Engine at Ignition

2018-04-03
2018-01-0208
Tumble motion plays a significant role in modern spark-ignition engines in that it promotes mixing of air/fuel for homogeneous combustion and increases the flame propagation speed for higher thermal efficiency and lower combustion variability. Cycle-by-cycle variations in the flow near the spark plug introduce variability to the initial flame kernel development, stretching, and convection, and this variability is carried over to the entire combustion process. The design of current direct-injection spark-ignition engines aims to have a tumble flow in the vicinity of the spark plug at the time of ignition. This work investigates how the flow condition changes in the vicinity of the spark plug throughout the late compression stroke via high-speed imaging of a long ignition discharge arc channel and its stretching, and via flow field measurement by particle imaging velocimetry.
Technical Paper

Weld Line Factors for Thermoplastics

2017-03-28
2017-01-0481
Weld lines occur when melt flow fronts meet during the injection molding of plastic parts. It is important to investigate the weld line because the weld line area can induce potential failure of structural application. In this paper, a weld line factor (W-L factor) was adopted to describe the strength reduction to the ultimate strength due to the appearance of weld line. There were two engineering thermoplastics involved in this study, including one neat PP and one of talc filled PP plastics. The experimental design was used to investigate four main injection molding parameters (melt temperature, mold temperature, injection speed and packing pressure). Both the tensile bar samples with/without weld lines were molded at each process settings. The sample strength was obtained by the tensile tests under two levels of testing speed (5mm/min and 200mm/min) and testing temperatures (room temperature and -30°C). The results showed that different materials had various values of W-L factor.
Technical Paper

CFD-Simulation and Validation of Cabin Pressure during Door Closing Motions

2019-04-02
2019-01-0815
Under the competitive pressure of automotive industry the customer’s focus is on a vehicle’s quality perception. Side door closing efforts make a considerable share of the overall impression as the doors are the first physical and haptic interface to the customer. Customer’s subjective feeling of vehicle quality demands for detailed analysis of each contributor of door closing efforts. Most contributors come from kinematic influences. Beside the losses due to mechanical subsystems like the checkarm, latch or hinge friction one of the biggest impacts originates from the pressure spike that builds up due to air being pushed into the cabin. Subject of this publication is to discuss the dependencies of closing efforts on cabin pressure and air extraction. It demonstrates an approach to simulate the development of the air pressure during door closing motions and the validation of the simulation method with the “EZ-Slam” measurement device.
Technical Paper

Parametric Simulation of Significant Design and Operating Alternatives Affecting the Fuel Economy and Emissions of Spark-Ignited Engines

1978-02-01
780943
A fundamental thermodynamic model of the complete spark-ignited, homogeneous charge engine cycle has been used in several parametric analyses to predict the effects of engine design and operating alternatives on fuel consumption and emissions of NOx and unburned hydrocarbons (HC). The simulation includes sub-models for wall heat transfer, NOx and HC emissions, and the engine breathing processes. This work demonstrates the power and utility of a comprehensive engine simulation by presenting several independent parametric studies that were carried out in response to genuine engine design and/or operating strategy questions. Included in this compilation are the effects of cycle heat loss, exhaust port heat loss, combustion duration, and charge dilution (EGR and/or lean air-fuel ratio). In addition, the influence of the design variables associated with bore-stroke ratio, intake and exhaust valve lift, and cam timing are considered.
Technical Paper

Experimental Investigation on the Influence of Pressure Wheel Design on Heat Dissipation for a Laser Robotic End of Arm Tooling

2018-04-03
2018-01-1235
The initiative of this paper is focused on improving the heat dissipation from the pressure wheel of a laser welding assembly in order to achieve a longer period of use. The work examines the effects of different geometrical designs on the thermal performance of pressure wheel assembly during a period of cooling time. Three disc designs were manufactured for testing: Design 1 – a plain wheel, Design 2 – a pierced wheel, and Design 3 – a wheel with ventilating vanes. All of the wheels were made of carbon steel. The transient thermal reaction were compared. The experimental results indicate that the ventilated wheel cools down faster with the convection in the ventilated channels, while the solid plain wheel continues to possess higher temperatures. A comparison among the three different designs indicates that the Design 3 has the best cooling performance.
Technical Paper

Automotive Refrigerant System Induced Evaporator Hoot

2005-05-16
2005-01-2509
The automotive refrigerant systems can occasionally exhibit a transient hoot/whistle type noise under certain operating conditions. High pressure/velocity refrigerant flow through an evaporator core can readily excite the inherent acoustical and/or structural modes, resulting in audible transient tones. This condition if present can be experienced while driving away from a short stop and can last 2 to 10 seconds. The ambient conditions suitable for creating this noise are - moderate/high air-conditioning (A/C) load during days at 85-95° F temperatures with high humidity. Possible noise generating mechanisms have been discussed in earlier publications and our findings during this study indicate that they are excited by the high velocity superheated refrigerant vapor flow through the evaporator core plates. Examples of this transient noise and its spectral characteristics are presented to characterize this refrigerant system induced issue.
Technical Paper

Dynamometer Development of a Lightly Stratified Direct Injection Combustion System

2004-03-08
2004-01-0547
This paper describes the dynamometer development of a lightly stratified direct-injection spark-ignition engine. The engine was designed for stratified charge operation at speeds and loads below 2000 RPM, 2 bar BMEP. Test results detailed in this report include evaluation of part-load stratified-charge, part-load homogeneous-charge, and WOT operation. The program had aggressive goals in improving WOT performance and part-load fuel consumption compared to a baseline PFI engine while meeting Stage V emissions levels. Mini-map analysis of the engine data indicated that the engine was able to meet the emissions and fuel consumption goals.
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