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Technical Paper

Toward the Environmentally-Friendly Small Engine: Fuel, Lubricant, and Emission Measurement Issues

1991-11-01
911222
Small engines which are friendly toward the environment are needed all over the world, whether the need is expressed in terms of energy efficiency, useful engine life, health benefits for the user, or emission regulations enacted to protect a population or an ecologically-sensitive area. Progress toward the widespread application of lower-impact small engines is being made through engine design, matching of engine to equipment and task, aftertreatment technology, alternative and reformulated fuels, and improved lubricants. This paper describes three research and development projects, focused on the interrelationships of fuels, lubricants, and emissions in Otto-cycle engines, which were conducted by Southwest Research Institute. All the work reported was funded internally as part of a commitment to advance the state of small engine technology and thus enhance human utility.
Technical Paper

An Engine Start/Stop System for Improved Fuel Economy

2007-04-16
2007-01-1777
During city traffic or heavily congested roads, a vehicle can consume a substantial amount of fuel idling when the vehicle is stopped. Due to regulation enforcement, auto manufacturers are developing systems to increase the mileage and reduce emissions. Turning off the engine at traffic lights and regenerative braking systems are simple ways to reduce emissions and fuel consumption. In order to develop strong manufacturer and consumer interest, this type of operation needs to be automated such that the stop/start functionality requires no driver interaction and takes place without the intervention of the vehicle operator. Valeo Electrical Systems has developed such a system that replaces the OEM engine alternator with a starter/alternator driven by a standard multi-ribbed V belt. To avoid a break and dual voltage network, this system is based on a 12V electrical system using an Enhanced Power Supply.
Technical Paper

The Use of Radioactive Tracer Technology in Studying Lubricant Chemistry to Enhance Bearing and Ring Wear Control in an Operating Engine

1994-10-01
941982
Radioactive tracer technology (RAT) is an important tool in measuring component wear in an operating engine on a real-time basis. This paper will discuss the use of RAT to study and evaluate boundary lubricant and surfactant chemistries aimed at providing benefits in wear control. In particular, RAT was employed to study ring and bearing wear as a function of engine operating condition (speed, load, and temperature) and lubricant characteristics. Prior to testing, the engine's compression rings and connecting rod bearings were subjected to bulk thermal neutron bombardment in a nuclear reactor to produce artificial radioisotopes that were separately characteristic of the ring and bearing wear surfaces. The irradiated parts were installed in the test engine, after which testing to a specific test matrix was accomplished.
Technical Paper

Noise Benchmarking of the Detroit Diesel DD15 Engine

2011-05-17
2011-01-1566
Several new or significantly upgraded heavy duty truck engines are being introduced in the North American market. One important aspect of these new or revised engines is their noise characteristics. This paper describes the noise related characteristics of the new DD15 engine, and compares them to other competitive heavy truck engines. DD15 engine features relevant to noise include a rear gear train, isolated oil pan and valve cover, and an amplified high pressure common rail fuel system. The transition between non-amplified and amplified common rail operation is shown to have a significant noise impact, not unlike the transition between pilot injection and single shot injection in some other engines.
Technical Paper

Observations from Cylinder Liner Wear Studies in Heavy Duty Diesel Engines and the Evolution towards Lower Viscosity Heavy Duty Engine Lubricants

2011-04-12
2011-01-1207
Since the invention of the internal combustion engine, the contact between piston ring and cylinder liner has been a major concern for engine builders. The quality and durability of this contact has been linked to the life of the engine, its maintenance, and its exhaust gas and blowby emissions, but also to its factional properties and therefore fuel economy. While the basic design has not changed, many factors that affect the performance of the ring/liner contact have evolved and are still evolving. This paper provides an overview of observations related to the lubrication of the ring/liner contact.
Journal Article

The Role of EGR in PM Emissions from Gasoline Engines

2010-04-12
2010-01-0353
A dilute spark-ignited engine concept has been developed as a potential low cost competitor to diesel engines by Southwest Research Institute (SwRI), with a goal of diesel-like efficiency and torque for light- and medium-duty applications and low-cost aftertreatment. The targeted aftertreatment method is a traditional three-way catalyst, which offers both an efficiency and cost advantage over typical diesel aftertreatment systems. High levels of exhaust gas recirculation (EGR) have been realized using advanced ignition systems and improved combustion, with significant improvements in emissions, efficiency, and torque resulting from using high levels of EGR. The primary motivation for this work was to understand the impact high levels of EGR would have on particulate matter (PM) formation in a port fuel injected (PFI) engine. While there are no proposed regulations for PFI engine PM levels, the potential exists for future regulations, both on a size and mass basis.
Technical Paper

The Impact of Engine Operating Conditions on Reformate Production in a D-EGR Engine

2017-03-28
2017-01-0684
Dedicated EGR has shown promise for achieving high efficiency with low emissions [1]. For the present study, a 4-cylinder turbocharged GDI engine which was modified to a D-EGR configuration was used to investigate the impact of valve phasing and different injection strategies on the reformate production in the dedicated cylinder. Various levels of positive valve overlap were used in conjunction with different approaches for dedicated cylinder over fueling using PFI and DI fuel systems. Three speed-load combinations were studied, 2000 rpm 4 bar IMEPg, 2000 rpm 12 bar IMEPg, and 4000 rpm 12 bar IMEPg. The primary investigation was conducted to map out the dedicated cylinders' performance at the operating limits of intake and exhaust cam phasing. In this case, the limits were defined as conditions that yielded either no reformate benefit or led to instability in the dedicated cylinder.
Technical Paper

Evaluation of Cold Start Technologies on a 3L Diesel Engine

2016-04-05
2016-01-0823
Increasingly stringent emissions regulations require that modern diesel aftertreatment systems must warm up and begin controlling emissions shortly after startup. While several new aftertreatment technologies have been introduced that focus on lowering the aftertreatment activation temperature, the engine system still needs to provide thermal energy to the exhaust for cold start. A study was conducted to evaluate several engine technologies that focus on improving the thermal energy that the engine system provides to the aftertreatment system while minimizing the impact on fuel economy and emissions. Studies were conducted on a modern common rail 3L diesel engine with a custom dual loop EGR system. The engine was calibrated for low engine-out NOx using various combustion strategies depending on the speed/load operating condition.
Technical Paper

Development of a New Valvetrain Wear Test - The Sequence IVB Test

2016-04-05
2016-01-0891
The study described in this paper covers the development of the Sequence IVB low-temperature valvetrain wear test as a replacement test platform for the existing ASTM D6891 Sequence IVA for the new engine oil category, ILSAC GF-6. The Sequence IVB Test uses a Toyota engine with dual overhead camshafts, direct-acting mechanical lifter valvetrain system. The original intent for the new test was to be a direct replacement for the Sequence IVA. Due to inherent differences in valvetrain system design between the Sequence IVA and IVB engines, it was necessary to alter existing test conditions to ensure adequate wear was produced on the valvetrain components to allow discrimination among the different lubricant formulations. A variety of test conditions and wear parameters were evaluated in the test development. Radioactive tracer technique (RATT) was used to determine the wear response of the test platform to various test conditions.
Technical Paper

Evaluation of Emerging Technologies on a 1.6 L Turbocharged GDI Engine

2018-04-03
2018-01-1423
Low-pressure loop exhaust gas recirculation (LP- EGR) combined with higher compression ratio, is a technology package that has been a focus of research to increase engine thermal efficiency of downsized, turbocharged gasoline direct injection (GDI) engines. Research shows that the addition of LP-EGR reduces the propensity to knock that is experienced at higher compression ratios [1]. To investigate the interaction and compatibility between increased compression ratio and LP-EGR, a 1.6 L Turbocharged GDI engine was modified to run with LP-EGR at a higher compression ratio (12:1 versus 10.5:1) via a piston change. This paper presents the results of the baseline testing on an engine run with a prototype controller and initially tuned to mimic an original equipment manufacturer (OEM) baseline control strategy running on premium fuel (92.8 anti-knock index).
Technical Paper

Optimization of Heavy Duty Diesel Engine Lubricant and Coolant Pumps for Parasitic Loss Reduction

2018-04-03
2018-01-0980
As fuel economy becomes increasingly important in all markets, complete engine system optimization is required to meet future standards. In many applications, it is difficult to realize the optimum coolant or lubricant pump without first evaluating different sets of engine hardware and iterating on the flow and pressure requirements. For this study, a Heavy Duty Diesel (HDD) engine was run in a dynamometer test cell with full variability of the production coolant and lubricant pumps. Two test stands were developed to allow the engine coolant and lubricant pumps to be fully mapped during engine operation. The pumps were removed from the engine and powered by electric motors with inline torque meters. Each fluid circuit was instrumented with volume flow meters and pressure measurements at multiple locations. After development of the pump stands, research efforts were focused on hardware changes to reduce coolant and lubricant flow requirements of the HDD engine.
Technical Paper

In-Situ Measurement of Transmission Efficiency in Vehicles

2017-03-28
2017-01-1095
SAE Recommended Practice J1540 [1] specifies test procedures to map transmission efficiency and parasitic losses in a manual transmission. The procedure comprises two parts. The first compares input and output torque over a range of speed to determine efficiency. The second measures parasitic losses at zero input torque over a range of speed. As specified in J1540, efficiency of transmissions is routinely measured on a test-stand under steady torque and speed [2] [3]. While such testing is useful to compare different transmissions, it is unclear whether the “in-use” efficiency of a given transmission is the same as that measured on the stand. A vehicular transmission is usually mated to a reciprocating combustion engine producing significant torque and speed fluctuations at the crankshaft. It is thus a valid question whether the efficiency under such pulsating conditions is the same as that under steady conditions.
Technical Paper

Achieving 0.02 g/bhp-hr NOx Emissions from a Heavy-Duty Stoichiometric Natural Gas Engine Equipped with Three-Way Catalyst

2017-03-28
2017-01-0957
It is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards of 0.20 g/bhp-hr, the National Ambient Air Quality Standards (NAAQS) requirements for ambient ozone will not be met. It is expected that further reductions in NOX emissions from the heavy-duty fleet will be required to achieve compliance with the ambient ozone requirement. To study the feasibility of further reductions, the California Air Resources Board (CARB) funded a research program to demonstrate the potential to reach 0.02 g/bhp-hr NOX emissions. This paper details the work executed to achieve this goal on the heavy-duty Federal Test Procedure (FTP) with a heavy-duty natural gas engine equipped with a three-way catalyst. A Cummins ISX-12G natural gas engine was modified and coupled with an advanced catalyst system.
Technical Paper

Utilizing Multiple Combustion Modes to Increase Efficiency and Achieve Full Load Dual-Fuel Operation in a Heavy-Duty Engine

2019-04-02
2019-01-1157
Reactivity Controlled Compression Ignition (RCCI) natural gas/diesel dual-fuel combustion has been shown to achieve high thermal efficiency with low NOX and PM emissions, but has traditionally been limited to low to medium loads. High BMEP operation typically requires high substitution rates (i.e., >90% NG), which can lead to high cylinder pressure, pressure rise rates, knock, and combustion loss. In previous studies, compression ratio was decreased to achieve higher load operation, but thermal efficiency was sacrificed. For this study, a multi-cylinder heavy-duty engine that has been modified for dual-fuel operation (diesel direct-injection and natural gas (NG) fumigated into the intake stream) was used to explore RCCI and other dual-fuel combustion modes at high compression ratio, while maintaining stock lug curve capability (i.e., extending dual-fuel operation to high loads where conventional diesel combustion traditionally had to be used).
Technical Paper

Investigation of a Spark-Assisted Diesel Engine

1983-02-01
830588
A single-cylinder, open-chamber direct-injection (OCDI) diesel engine was converted to low compression ratio, spark-assisted operation. A modular construction cylinder head was built for the test work. The research work indicated that on a typical OCDI diesel engine, several spark plug locations are possible to produce successful ignition of a wide range of fuels. Performance tests were run with different compression and swirl ratio combinations. The best combination was found to be 12.2 compression ratio and 10 swirl ratio. The spark-assisted engine (CR 16:1) was performance tested with methanol and DF-2 plus 20% methanol emulsified fuel. The spark was always required with methanol, however, with emulsified fuel spark was desirable for starting and warming up periods. The investigation suggested the feasibility of economically developing multi-fuel spark-assisted diesel engines.
Technical Paper

Low Heat Rejection Engines

1986-03-01
860314
The paper gives a general overview of the state-of-the-art in low heat rejection (LHR) engines. It also gives experimental results obtained at SwRI with a single-cylinder research engine using an electrically heated cylinder liner to simulate LHR operation and examine the effects of increased liner temperature. It was concluded that the improvement in fuel economy from LHR operation is negligible in naturally-aspirated (NA) engines, about 7 percent in turbocharged (TC) engines and about 15 percent in turbocompound (TCO) engines. LHR operation reduces power in NA engines only. It increases NOx emissions by around 15 percent, but reduces HC and CO emissions. LHR operation offers benefits in the reduction of noise and smoke, and in operation on low cetane fuels. Much more research is needed to overcome the practical problems before LHR engines can be put into production.
Technical Paper

Methodology Development for Tumble Port Evaluation

2016-04-05
2016-01-0636
The objective of this work was to develop a methodology to rapidly assess comparative intake port designs for their capability to produce tumble flow in spark-ignition engine combustion chambers. Tumble characteristics are of relatively recent interest, and are generated by a combination of intake port geometry, valve lift schedule, and piston motion. While simple approaches to characterize tumble from steady-state cylinder head flow benches have often been used, the ability to correlate the results to operating engines is limited. The only available methods that take into account both piston motion and valve lift are detailed computational fluid dynamic (CFD) analysis, or optical measurements of flow velocity. These approaches are too resource intensive for rapid comparative assessment of multiple port designs. Based on the best features of current steady-flow testing, a simplified computational approach was identified to take into account the important effects of the moving piston.
Technical Paper

Laser Ignition in a Pre-Mixed Engine: The Effect of Focal Volume and Energy Density on Stability and the Lean Operating Limit

2005-10-24
2005-01-3752
A series of tests using an open beam laser ignition system in an engine run on pre-mixed, gaseous fuels were performed. The ignition system for the engine was a 1064 nm Nd:YAG laser. A single cylinder research engine was run on pre-mixed iso-butane and propane to determine the lean limit of the engine using laser ignition. In addition, the effect of varying the energy density of the ignition kernel was investigated by changing the focal volume and by varying laser energy. The results indicate that for a fixed focal volume, there is a threshold beyond which increasing the energy density [kJ/m3] yields little or no benefit. In contrast, increasing the energy density by reducing the focal volume size decreases lean performance once the focal volume is reduced past a certain point. The effect of ignition location relative to different surfaces in the engine was also investigated. The results show a slight bias in favor of igniting closer to a surface with low thermal conductivity.
Technical Paper

Effects of Engine Operating Conditions on In-Cylinder Air/Fuel Ratio Detection Using a Production Ion Sensing Device

2004-03-08
2004-01-0515
In-cylinder ion sensing through sparkplug electrodes can be used to determine in-cylinder A/F ratio by using a modified production coil-on-plug ignition system having ion sensing capability. The in-cylinder ionization can be characterized by the height of the peak, location of the peak from ignition command and area under the ionization signal curve. The effects of A/F ratio on the in-cylinder ionization can be isolated from other affecting factors by conducting tests on a constant volume combustion device in which the initial pressure and temperature can be well controlled. This results in a parabolic correlation of the ionization characteristics with the mixture equivalence ratio. Additionally the ionization characteristics show strong dependence on engine load and speed. Equivalence ratio characteristics during engine cranking and warm up are investigated, and a method for on-line calibration of ionization detection is discussed.
Technical Paper

On-Board Fuel Property Classifier for Fuel Property Adaptive Engine Control System

2006-04-03
2006-01-0054
This paper explores the possibility of on-board fuel classification for fuel property adaptive compression-ignition engine control system. The fuel classifier is designed to on-board classify the fuel that a diesel engine is running, including alternative and renewable fuels such as bio-diesel. Based on this classification, the key fuel properties are provided to the engine control system for optimal control of in-cylinder combustion and exhaust treatment system management with respect to the fuel. The fuel classifier employs engine input-output response characteristics measured from standard engine sensors to classify the fuel. For proof-of-concept purposes, engine input-output responses were measured for three different fuels at three different engine operating conditions. Two neural-network-based fuel classifiers were developed for different classification scenarios. Of the three engine operating conditions tested, two conditions were selected for the fuel classifier to be active.
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