Your Selections

Worm, Jeremy
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Methods of Pegging Cylinder Pressure to Maximize Data Quality

Michigan Tech APS LABS-Jeremy Worm
Michigan Technological Univ-Darrell Robinette
Published 2019-04-02 by SAE International in United States
Engine cylinder pressure is traditionally measured with a piezo-electric pressure transducer, and as such, must be referenced or pegged to a known value. Frequently, the cylinder pressure is pegged to the pressure in the intake manifold plenum whereby the manifold absolute pressure (MAP) at the end of the intake stroke is measured and the cylinder pressure trace for the entire cycle is adjusted such that the cylinder pressure is set equal to the manifold pressure at the end of the intake stroke. However, any error in pegging induces an error in the cylinder pressure trace, which has an adverse effect on the entire combustion analysis. This research is focused on assessing the pegging error for several pegging methods across a wide range of engine operating conditions, and ultimately determining best practices to minimize error in pegging and the calculated combustion metrics. The study was conducted through 1D simulations using the commercially available GT-Power. The test matrix included variations of speed, load, intake runner length and intake valve timing. Five different pegging locations were compared, and…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Water Injection as an Enabler for Increased Efficiency at High-Load in a Direct Injected, Boosted, SI Engine

SAE International Journal of Engines

Michigan Tech APS Labs-Jeremy Worm, Jeffrey Naber, Joel Duncan
Nostrum Energy LLC-Sam Barros, William Atkinson
  • Journal Article
  • 2017-01-0663
Published 2017-03-28 by SAE International in United States
In a Spark-Ignited engine, there will come a point, as load is increased, where the unburned air-fuel mixture undergoes auto-ignition (knock). The onset of knock represents the upper limit of engine output, and limits the extent of engine downsizing / boosting that can be implemented for a given application. Although effective at mitigating knock, requiring high octane fuel is not an option for most markets. Retarding spark timing can extend the high load limit incrementally, but is still bounded by limits for exhaust gas temperature, and spark retard results in a notable loss of efficiency. Likewise, enriching the air-fuel mixture also decreases efficiency, and has profound negative impacts on engine out emissions. In this current work, a Direct-Injected, Boosted, Spark-Ignited engine with Variable Valve Timing was tested under steady state high load operation. Comparisons were made among three fuels; an 87 AKI, a 91 AKI, and a 110 AKI off-road only race fuel. The engine was outfitted with a sequential port water injection apparatus. Under full-load, water injection enabled operation with 87 AKI fuel at…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Determination of Vehicle Frontal Area Using Image Processing

General Motors Company-Christopher Morgan
Michigan Technological University-Drew D. Brennan, Jeremy Worm
Published 2013-04-08 by SAE International in United States
The projected frontal area of a vehicle has a significant impact on aerodynamic drag, and thus is an important parameter, for vehicle development, benchmarking, and modeling. However, determining vehicle frontal area can be tedious, time consuming, expensive, or inaccurate. Existing methods include analysis of engineering drawings, vehicle projections, 3D scanners, planimeter measurements from photographs, and estimations using vehicle dimensions. Currently accepted approximation methods can be somewhat unreliable.This study focuses on introducing a method to find vehicle frontal area using digital images and subtraction functions via MATLABs' Image Processing Toolbox. In addition to an overview of the method, this paper describes several variables that were examined to optimize and improve the process such as camera position, surface glare, and vehicle shadow effects.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Development of an Improved Residuals Estimation Model for Dual Independent Cam Phasing Spark-Ignition Engines

Michigan Technological Univ-Vaibhav Kale, Yeliana Yeliana, Jeremy Worm, Jeffrey Naber
Published 2013-04-08 by SAE International in United States
Estimating internal residual during engine operation is essential to robust control during startup, steady state, and transient operation. Internal residual has a significant effect on combustion flame propagation, combustion stability and emissions. Accurate residual estimate also provides a better foundation for optimizing open loop fuel control during startup, while providing a basis for reducing emissions during closed loop control.In this paper we develop an improved model to estimate residual gas fraction by means of isolation and characterization of the physical processes in the gas exchange. Examining existing residuals model as the base, we address their deficiencies making changes to appropriate terms to the model. Existing models do not work well under wide angle dual independent cam phasing. The improved residual estimation model is not limited by the initial data set used for its calibration and does not need cylinder pressure data. The model can work with different valve lift profiles and compression ratios. The model is calibrated by using two datasets, a single cylinder engine simulation dataset comprising of a range of speeds from 180…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Combustion Robustness Characterization of Gasoline and E85 for Startability in a Direct Injection Spark-Ignition Engine

GM Powertrain-Halim Santoso, Craig Marriott
Michigan Technological Univ-Vaibhav Kale, Jeremy Worm, Jeffrey Naber
Published 2012-04-16 by SAE International in United States
An experimental study and analysis was conducted to investigate cold start robustness of an ethanol flex-fuel spark ignition (SI) direct injection (DI) engine. Cold starting with ethanol fuel blends is a known challenge due to the fuel characteristics. The program was performed to investigate strategies to reduce the enrichment requirements for the first firing cycle during a cold start. In this study a single-cylinder SIDI research engine was used to investigate gasoline and E85 fuels which were tested with three piston configurations (CR11F, CR11B, CR15.5B - which includes changes in compression ratio and piston geometry), at three intake cam positions (95, 110, 125 °aTDC), and two fuel pressures (low: 0.4 MPa and high: 3.0 MPa) at 25°C±1°C engine and air temperature, for the first cycle of an engine start. The goal of this work was to simulate, test and investigate the engine's initial combustion cycle (1st fired cycle) including engine speed, manifold pressure, fuel pressure and ambient temperature (FTP testing temperature). The results revealed several trends with respect to hardware and fuel interactions: for gasoline,…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

The Effects of Oxygenated Biofuel on Intake Oxygen Concentration, EGR, and Performance of a 1.9L Diesel Engine

Michigan Technological Univ.-Christopher John Polonowski, Scott Miers, Michael Lecureux, Jay Shah, Jeffrey Naber, Jeremy Worm
Published 2010-04-12 by SAE International in United States
Exhaust gas recirculation (EGR) has been employed in a diesel engine to reduce NOx emissions by diluting the fresh air charge with gases composed of primarily N2, CO2, H2O, and O2 from the engines exhaust stream. The addition of EGR reduces the production of NOx by lowering the peak cylinder gas temperature and reducing the concentration of O2 molecules, both of which contribute to the NOx formation mechanism. The amount of EGR has been typically controlled using an open loop control strategy where the flow of EGR was calibrated to the engine speed and load and controlled by the combination of an EGR valve and the ratio of the boost and exhaust back pressures. When oxygenated biofuels with lower specific energy are used, the engine control unit (ECU) will demand a higher fuel rate to maintain power output, which can alter the volumetric flow rate of EGR. In addition, oxygenated biofuels affect the oxygen concentration in the intake manifold gas stream. The following work utilized an analytical analysis of EGR and experimental engine data to…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

The Calculation of Mass Fraction Burn of Ethanol-Gasoline Blended Fuels Using Single and Two-Zone Models

Michigan Technological University- Yeliana, Christopher Cooney, Jeremy Worm, Jeffrey Naber
Published 2008-04-14 by SAE International in United States
One-dimensional single-zone and two-zone analyses have been exercised to calculate the mass fraction burned in an engine operating on ethanol/gasoline-blended fuels using the cylinder pressure and volume data. The analyses include heat transfer and crevice volume effects on the calculated mass fraction burned. A comparison between the two methods is performed starting from the derivation of conservation of energy and the method to solve the mass fraction burned rates through the results including detailed explanation of the observed differences and trends. The apparent heat release method is used as a point of reference in the comparison process. Both models are solved using the LU matrix factorization and first-order Euler integration.Experiments were conducted with a Cooperative Fuels Research (CFR) engine holding Net Indicated Mean Effective Pressure (Net IMEP) constant at 330 kPa and fueling at the respective stoichiometric condition for the air flow and ethanol fuel blend being tested. This study included four ethanol-gasoline fuel blends: E20, E40, E60, E84, and gasoline (E0) as a baseline. The results show that all three models consistently produce similar…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

The Effect of Exhaust Variable Cam Phaser Transients on Equivalence Ratio Control in an SI 4 Stroke Engine

GM Powertrain-Jeremy Worm
Published 2005-04-11 by SAE International in United States
It is a well established fact that variable camshaft phasing can be used to reduce engine out emissions during steady state operation. However, a transition in camshaft timing which often accompanies engine speed / load changes, can have a significant dynamic impact on volumetric efficiency. The change in volumetric efficiency can be highly unpredictable, and can last for several engine cycles following the endpoint of cam movement. Since precise control of catalyst feedgas equivalence ratio is crucial to meeting increasingly stringent automotive emission requirements, the steady state benefits of cam phasing can be overshadowed by the loss of A/F control during transient operation if the engine control algorithms are not properly designed and calibrated. This paper investigates the impact of exhaust variable cam phaser transients on equivalence ratio control, and the mechanism by which volumetric efficiency is affected.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

An Evaluation of Several Methods for Calculating Transient Trapped Air Mass with Emphasis on the “Delta P” Approach

GM Powertrain-Jeremy Worm
Published 2005-04-11 by SAE International in United States
Existing literature describes a method (termed the “Delta P” method) by which experimentally measured cylinder pressure data can be used to compute the mass of fresh air trapped within the cylinder of an IC engine. It is reported that this method provides a means for analyzing transient engine behavior on a cycle-by-cycle basis. The objective of the current paper is to examine the Delta P method in greater detail, and compare its strengths and weaknesses to other potential methods of computing cyclic trapped mass. It will be shown that although there are limits to its application, the Delta P method has advantages over other methods, and proves to be a useful analysis technique when transient engine operation is to be studied.
Annotation ability available