The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x

Your Selections

Yang, Jialin
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.

The Feasibility of an Alumina-Based Lean NOx Trap (LNT) for Diesel and HCCI Applications

Research and Innovation Center Ford Motor Company-Lifeng Xu, George Graham, Robert McCabe, John Hoard, Jialin Yang
Published 2008-04-14 by SAE International in United States
An alumina-based LNT is being developed through laboratory studies, for diesel vehicle applications. This LNT provides high NOx conversion efficiency at low temperature (150 to 350°C, especially below 200°C), which is very important for the exhaust-gas after-treatment of diesel passenger vehicles. Addition of 2 to 4 wt% of alkaline-earth metal oxide or other metal oxides to the alumina LNT formulation improves NOx reduction activity at the high end of its active temperature window. More significantly, the alumina-based LNT can undergo the de-SOx process (the process of removing sulfur from the catalytic surfaces) very efficiently: within 1 minute at the relatively low temperature of 500 to 650°C under slightly rich conditions (λ = 0.98 to 0.987). Such a mild de-SOx process imposes minimal thermal exposure, causing almost no thermal damage to the LNT, and helps minimize the associated fuel penalty. The alumina-based LNT could thus provide a solution to the current LNT durability issue caused by sulfur poisoning and the need to aggressively de-SOx at high temperature. Possible applications of the alumina-based LNT for diesel and…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

On HCCI Engine Knock

Jialin Yang
Ford Research and Advanced Engineering-Thomas Kenney
Published 2007-07-23 by SAE International in United States
Knock in a HCCI engine was examined by comparing subjective evaluation, recorded sound radiation from the engine, and cylinder pressure. Because HCCI combustion involved simultaneous heat release in a spatially large region, substantial oscillations were often found in the pressure signal. The time development of the audible signal within a knock cycle was different from that of the pressure trace. Thus the audible signal was not the attenuated transmission of the cylinder pressure oscillation but the sound radiation from the engine structure vibration excited by the initial few cycles of pressure oscillation. A practical knock limited maximum load point for the specific 2.3 L I4 engine under test (and arguably for engines of similar size and geometry) was defined at when the maximum rate of cycle-averaged pressure rise reached 5 MPa/ms.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effect of Air Temperature and Humidity on Gasoline HCCI Operating in the Negative-Valve-Overlap Mode

Jialin Yang
Ford Research and Advanced Engineering-Thomas Kenney
Published 2007-04-16 by SAE International in United States
The impact of intake air temperature and humidity on gasoline HCCI engine operation was assessed. The 2.3 L I4 production engine modified for single cylinder operation was controlled by using variable cam phasing on both the intake and exhaust valve in the negative-valve-overlap mode. Exhaust cam phasing was mainly used to control load, and intake cam phasing was mainly used to control combustion phasing. At stoichiometric condition, higher intake air temperature advanced combustion phasing and promoted knock, resulting in a 19% reduction of the Net Indicated Mean Effective Pressure (NIMEP) at the high load limit at 1500 rpm when intake temperature was changed from −10 to 100° C. Higher ambient humidity delayed combustion phasing. For stoichiometric operation, this delay allowed a small extension (a few tenths of a bar in NIMEP) in the high load limit when the moisture concentration was changed from 3 to 30 g/m3 (corresponding to 10-100% relative humidity at 28° C). The low load limit was not sensitive to the ambient temperature and humidity because of the high level of residual…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Robustness and Performance Near the Boundary of HCCI Operating Regime of a Single-Cylinder OKP Engine

Ford Motor Co.-Jialin Yang, Thomas Kenney
Published 2006-04-03 by SAE International in United States
A single-cylinder OKP (optimized kinetic process) engine, which uses homogeneous-charge compression-ignition (HCCI) technology, was tested, following a previous study, to evaluate the combustion system robustness and to improve the engine performance near the boundaries of the HCCI operating regime at light loads, high loads and high speed.To evaluate the robustness of HCCI combustion control, gasoline fuels with different RON were used, and the engine was tested at different coolant temperatures. It was demonstrated that the proposed HCCI control approaches could control the OKP engine system to operate robustly using different fuels and at different coolant temperatures.The effects of fuel injection timing and residual gas fraction on HCCI combustion and emissions, especially CO emissions and combustion efficiency, were tested at light loads; and the mechanisms were analyzed. At high loads, the effects of intake pressure and residual gas fraction on the combustion rate, knocking tendency, NOx emissions and the sensitivity of HCCI combustion timing control were investigated. The HCCI combustion-timing-control sensitivity at different engine speeds was also evaluated. Knowledge from this study may help in improving…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Detailed Hydrocarbon Species and Particulate Emissions from a HCCI Engine as a Function of Air-Fuel Ratio

Ford Motor Company-Edward W. Kaiser, M. Matti Maricq, Ning Xu, Jialin Yang
Published 2005-10-24 by SAE International in United States
Concentrations of individual species in the engine-out exhaust gas from a gasoline-fueled (101.5 or 91.5 RON), direct-injection, compression-ignition (HCCI) engine have been measured by gas chromatography over the A/F range 50 to 230 for both stratified and nearly homogeneous fuel-air mixtures. The species identified include hydrocarbons, oxygenated organic species, CO, and CO2. A single-cylinder HCCI engine (CR = 15.5) with heated intake charge was used. Measurements of the mass and size distribution of particulate emissions were also performed.The 101.5 RON fuel consisted primarily of five species, simplifying interpretation of the exhaust species data: iso-pentane (24%), iso-octane (22%), toluene (17%), xylenes (10%), and trimethylbenzenes (9%). The thermal oxidation of iso-pentane and iso-octane were studied individually during brief experiments in a Pyrex reactor in order to ascertain the major primary and secondary products formed during oxidation of these fuel components at 765 K.A sharp increase occurs in the emissions indices of the organics formed by the combustion of the major fuel components beginning near A/F = 70. These product mole fractions increase by factors of 15 to…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Some Concepts of DISI Engine for High Fuel Efficiency and Low Emissions

Ford Motor Co.-Jialin Yang, Thomas Kenney
Published 2002-10-21 by SAE International in United States
Stratified-charge DISI engines have been launched in the market by Mitsubishi, Toyota, and Nissan. This paper discusses the current production stratified-charge DISI systems and some alternative systems, including the system using air-forced fuel injection and a proposed system that uses a swirl flow in the piston bowl with a special shape to separate the fuel-rich mixture layer from the wall surface. New DISI concepts are proposed to overcome some drawbacks of current bowl-in-piston type stratified-charge DISI systems. Charge stratification can be realized by using a soft spray with proper spray penetration, droplet size, and cone angle, as shown by CFD simulation results. The drawbacks of fuel wall wetting, soot limited load with charge stratification, large surface to volume ratio, etc., of the bowl-in-piston type system can be minimized. Bench tests with a conventional DI swirl-type injector showed that a liquid spray impinging on a semispherical target could produce a suitable soft spray fuel cloud. Finally, an engine combining homogeneous-charge DISI and variable valve timing may achieve the same fuel efficiency level as an emission constrained…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Development of a Gasoline Engine System Using HCCI Technology - The Concept and the Test Results

Ford Motor Co.-Jialin Yang, Todd Culp, Thomas Kenney
Published 2002-10-21 by SAE International in United States
Homogeneous-charge compression-ignition (HCCI) technology has high potential to significantly reduce fuel consumption and NOx emissions over PFI engines. Control of the HCCI combustion process over the full range of conventional PFI operating conditions, however, has been a challenge. This study describes an HCCI-SI dual-mode engine system proposal based on new approaches to optimize the engine performance. A 0.658L single-cylinder engine was built and tested using these concepts. The engine was operated in HCCI mode from idle to 5.5 bar NMEP and up to 4750 rpm. NSFC in HCCI mode was about 175 g/kWh over most of the operating range except at very low load or near the high load boundary. At a part load of 1500 rpm and an equivalent BMEP of 2.62 bar, net indicated fuel efficiency was 50% higher than PFI engines and 30% higher than a prototype SC-DISI engine. Net specific NOx emissions were lower than 0.1 g/kWh below 4 bar NMEP, approximately two orders of magnitude lower than those from both SC-DISI and PFI engines. Boosting the intake pressure at loads…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Study of a Stratified-Charge DISI Engine with an Air-Forced Fuel Injection System

Ford Motor Co.-Jialin Yang, Ruben H. Munoz, Richard W. Anderson, George A. Lavoie
Published 2000-06-19 by SAE International in United States
A small-bore 4-stroke single-cylinder stratified-charge DISI engine using an air-forced fuel injection system has been designed and tested under various operating conditions. At light loads, fuel consumption was improved by 16∼19% during lean, stratified-charge operation at an air-fuel ratio of 37. NOx emissions, however, were tripled. Using EGR during lean, stratified-charge operation significantly reduced NOx emissions while fuel consumption was as low as the best case without EGR. It was also found that combustion and emissions near the lean limit were a strong function of the combination of injection and spark timings, which affect the mixing process. Injection pressure, air injection duration, and time delay between fuel and air injections also played a role. Generating in-cylinder air swirl motion slightly improved fuel economy. Additionally, it was found that stratified-charge operation at medium-high load was not constrained by soot emissions, and speeds up to 3000 rpm could be achieved with stratified charge operation. At full load, the knocking tendency was reduced and the maximum torque output was increased versus PFI operation.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Sooting Tendencies in an Air-Forced Direct Injection Spark-Ignition (DISI) Engine

Research Lab, Ford Motor Company-M. Matti Maricq, Ruben H. Munoz, Jialin Yang, Richard W. Anderson
Published 2000-03-06 by SAE International in United States
Particulate emissions are reported for a 0.31 L single cylinder engine fitted with an air forced direct injection system. Trends in number, size, and mass of engine out particle emissions are examined as a function of injection timing, spark timing, and EGR. Injection timing determines to a large degree the nature of the combustion, with early injection leading to homogeneous like combustion and late injection producing stratified charge combustion. As fuel injection is retarded, at a fixed lean air to fuel ratio, PM emissions decline to a minimum at an injection time well within the compression stroke, after which they rapidly increase. In the heavily stratified regime, the PM increase can be attributed to a growing number of rich zones that occur in the progressively more inhomogeneous fuel mixture. At fixed injection timing, advancing the spark causes a general increase in particle emissions. This trend is opposite that of hydrocarbons, which decrease significantly as spark timing is advanced. A limited examination of the effect of EGR shows it to reduce NOx. However, PM, CO, and…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Characteristics of Direct Injection Gasoline Spray Wall Impingement at Elevated Temperature Conditions

Ford Research Laboratory-Jialin Yang, Zhiyu Han, Richard W. Anderson
Wayne State University-Junesung Park, Xingbin Xie, Kyoung-Su Im, Hoisan Kim, Ming-Chia Lai
Published 1999-10-25 by SAE International in United States
The direct injection gasoline spray-wall interaction was characterized inside a heated pressurized chamber using various visualization techniques, including high-speed laser-sheet macroscopic and microscopic movies up to 25,000 frames per second, shadowgraph, and doublespark particle image velocimetry. Two hollow cone high-pressure swirl injectors having different cone angles were used to inject gasoline onto a heated plate at two different impingement angles. Based on the visualization results, the overall transient spray impingement structure, fuel film formation, and preliminary droplet size and velocity were analyzed.The results show that upward spray vortex inside the spray is more obvious at elevated temperature condition, particularly for the wide-cone-angle injector, due to the vaporization of small droplets and decreased air density. Film build-up on the surface is clearly observed at both ambient and elevated temperature, especially for narrow cone spray. Vapor phase appears at both ambient and elevated temperature conditions, particularly in the toroidal vortex and impingement plume. More rapid impingement and faster horizontal spread after impingement are observed for elevated temperature conditions. Droplet rebounding and film break-up are clearly observed. Post-impingement…
Annotation ability available