OPTIMIZATION OF INTAKE PORT DESIGN FOR SI ENGINE

Y. L. QI,L. C. DONG,H. LIU,P. V. PUZINAUSKAS,K. C. MIDKIFF 한국자동차공학회 2012 International journal of automotive technology Vol.13 No.6

It is well known that in-cylinder flow is very important factor for the performance of SI engine. An appropriate in-cylinder flow pattern can enhance the turbulence intensity at spark time, therefore increasing the stability of combustion, reducing emission and improving fuel economy. In this paper, the effect of intake port design on in-cylinder flow is studied. It is found a vortex existed at the upper side of intake port of a production SI engine used in the study, during the intake stroke, which will reduce both tumble ratio and volumetric efficiency. A minor modification on intake port is made to eliminate the vortex and increase tumble ratio while keeping volumetric efficiency at the same level. It is demonstrated that the increase in tumble in the new design results in a 20 per cent increase in the fuel vaporization. In this study, both KIVA and STAR-CD are used to simulate the engine cold flow, as well as ICEM CFD and es-ice used as pre-processor respectively due to the complexity of engine geometry. Simulation results from KIVA and STAR-CD are compared and analyzed.

In vitro reconstitution of the cyclosporine specific P450 hydroxylases using heterologous redox partner proteins

Sun, Y.,Ma, L.,Han, D.,Du, L.,Qi, F.,Zhang, W.,Sun, J.,Huang, S.,Kim, E. S.,Li, S. SPRINGER 2017 Journal of industrial microbiology & biotechnology Vol.44 No.2

<P>The cytochrome P450 enzymes (CYPs) CYP-sb21 from Sebekia benihana and CYP-pa1 from Pseudonocardia autotrophica are able to hydroxylate the immunosuppressant cyclosporin A (CsA) in a regioselective manner, giving rise to the production of two hair-stimulating agents (with dramatically attenuated immunosuppressant activity), gamma-hydroxy-N-methyl-l-Leu4-CsA (CsA-4-OH) and gamma-hydroxy-N-methyl-l-Leu9-CsA (CsA-9-OH). Recently, the in vitro activity of CYP-sb21 was identified using several surrogate redox partner proteins. Herein, we reconstituted the in vitro activity of CYP-pa1 for the first time via a similar strategy. Moreover, the supporting activities of a set of ferredoxin (Fdx)/ferredoxin reductase (FdR) pairs from the cyanobacterium Synechococcus elongatus PCC 7942 were comparatively analyzed to identify the optimal redox systems for these two CsA hydroxylases. The results suggest the great value of cyanobacterial redox partner proteins for both academic research and industrial application of P450 biocatalysts.</P>

NUMERICAL ANALYSIS OF HOMOGENEOUS MIXTURE FORMATION FOR A DIRECT INJECTION LIQUID LPG ENGINE

B. Y. XU,X. C. ZHANG,J. XU,Y. L. QI,S. L. CAI 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.6

A method to form a homogeneous mixture using low pressure direct injection of liquid phase LPG, pent-roof combustion chamber, flat-top piston and center-located injector layout is presented. To validate the method, the mixture formation processes in the cylinder were investigated using the CFD code. The effect of different injection timing and engine loads on the mixture formation processes were researched. The simulated results showed that, the intake tumble for high load conditions or the inclined intake swirl for part load conditions would break into small-scale vortex (turbulence) near the end of compression stroke, which enhanced the homogeneous mixture formation. The results also showed that if the liquid phase LPG was injected at 60-80oCA ATDC in intake stroke even at different loads, the homogeneous mixture would be formed under any engine load conditions.

FUEL PROPERTIES AND EMISSIONS CHARACTERISTICS OF ETHANOL-DIESEL BLEND ON SMALL DIESEL ENGINE

B. Y. XU,Y. L. QI,W. B. ZHANG,S. L. CAI 한국자동차공학회 2007 International journal of automotive technology Vol.8 No.1

Phase separation and low cetane number are the main barriers to the large-scale use of ethanol-diesel blend fuel on small diesel engines. In this paper, an additive package is designed on the basis of the blended fuel properties to overcome these limitations. The experiments show that the solubility of ethanol in diesel is evidently increased by adding 1~2% (in volume) of the additive package and the flammability of ethanol-diesel blend fuel with the additive has reached the neat diesel level under the cold start conditions. Effects of the ethanol content in diesel on fuel economy, combustion characteristics, and emission characteristics are also investigated with the ethanol blend ratios of 10%, 20% and 30%. The increase in ethanol content shows that the specific fuel consumption and the brake thermal efficiency are both gradually increased compared to neat diesel. The soot concentrations of the three blended fuels are all greatly lower than that of neat diesel. NOx emission is increased with an increase in the engine load and is reduced with the increase in the ethanol blend ratio under a high load.

NUMERICAL ANALYSIS OF FUEL INJECTION IN INTAKE MANIFOLD AND INTAKE PROCESS OF A MPI NATURAL GAS ENGINE

B. Y. XU,F. Y. LIANG,S. L. CAI,Y. L. QI 한국자동차공학회 2005 International journal of automotive technology Vol.6 No.6

Unsteady state free natural gas jets injected from several types of injectors were numerically simulated. Simulations showed good agreements with the schlieren experimental results. Moreover, injections of natural gas in intake manifolds of a single-valve engine and a double-valve engine were predicted as well. Predictions revealed that large volumetric injections of natural gas in intake manifolds led to strong impingement of natural gas with the intake valves, which as a result, gave rise to pronounced backward reflection of natural gas towards the inlets of intake manifolds, together with significant increase in pressure in intake manifold. Based on our simulations, we speculated that for engines with short intake manifolds, reflections of the mixture of natural gas and air were likely to approach the inlets of intake manifolds and subsequently be inbreathed into other cylinders, resulting in non-uniform mixture distributions between the cylinders. For engines with long intake manifolds, inasmuch as the degrees of intake interferences between the cylinders were not identical in light of the ignition sequences, non-uniform intake charge distributions between the cylinders would occur.

NUMERICAL ANALYSIS OF FUEL INJECTION IN INTAKE MANIFOLD AND INTAKE PROCESS OF A MPI NATURAL GAS ENGINE

XU B. Y.,LIANG F. Y.,CAI S. L.,QI Y. L. The Korean Society of Automotive Engineers 2005 International journal of automotive technology Vol.6 No.6

Unsteady state free natural gas jets injected from several types of injectors were numerically simulated. Simulations showed good agreements with the schlieren experimental results. Moreover, injections of natural gas in intake manifolds of a single-valve engine and a double-valve engine were predicted as well. Predictions revealed that large volumetric injections of natural gas in intake manifolds led to strong impingement of natural gas with the intake valves, which as a result, gave rise to pronounced backward reflection of natural gas towards the inlets of intake manifolds, together with significant increase in pressure in intake manifold. Based on our simulations, we speculated that for engines with short intake manifolds, reflections of the mixture of natural gas and air were likely to approach the inlets of intake manifolds and subsequently be inbreathed into other cylinders, resulting in non-uniform mixture distributions between the cylinders. For engines with long intake manifolds, inasmuch as the degrees of intake interferences between the cylinders were not identical in light of the ignition sequences, non-uniform intake charge distributions between the cylinders would occur.

FUEL PROPERTIES AND EMISSIONS CHARACTERISTICS OF ETHANOL-DIESEL BLEND ON SMALL DIESEL ENGINE

Xu, B.Y.,Qi, Y.L.,Zhang, W.B.,Cai, S.L. The Korean Society of Automotive Engineers 2007 International journal of automotive technology Vol.8 No.1

Phase separation and low cetane number are the main barriers to the large-scale use of ethanol-diesel blend fuel on small diesel engines. In this paper, an additive package is designed on the basis of the blended fuel properties to overcome these limitations. The experiments show that the solubility of ethanol in diesel is evidently increased by adding $1{\sim}2%$ (in volume) of the additive package and the flammability of ethanol-diesel blend fuel with the additive has reached the neat diesel level under the cold start conditions. Effects of the ethanol content in diesel on fuel economy, combustion characteristics, and emission characteristics are also investigated with the ethanol blend ratios of 10%, 20% and 30%. The increase in ethanol content shows that the specific fuel consumption and the brake thermal efficiency are both gradually increased compared to neat diesel. The soot concentrations of the three blended fuels are all greatly lower than that of neat diesel. $NO_x$ emission is increased with an increase in the engine load and is reduced with the increase in the ethanol blend ratio under a high load.

Trypsin immobilization in ordered porous polymer membranes for effective protein digestion

Qiao, J.,Kim, J.Y.,Wang, Y.Y.,Qi, L.,Wang, F.Y.,Moon, M.H. Elsevier Pub. Co 2016 Analytica chimica acta Vol.906 No.-

Fast and effective protein digestion is a vital process for mass spectrometry (MS) based protein analysis. This study introduces a porous polymer membrane enzyme reactor (PPMER) coupled to nanoflow liquid chromatography-tandem MS (nLC-ESI-MS/MS) for on-line digestion and analysis of proteins. Poly (styrene-co-maleic anhydride) (PS-co-MAn) was fabricated by the breath figure method to make a porous polymer membrane in which the MAn group was covalently bound to enzyme. Based on this strategy, microscale PPMER (μPPMER) was constructed for on-line connection with the nLC-ESI-MS/MS system. Its capability for enzymatic digestion with bovine serum albumin (BSA) was evaluated with varied digestion periods. The on-line proteolysis of BSA and subsequent analysis with μPPMER-nLC-ESI-MS/MS revealed that peptide sequence coverage increased from 10.3% (digestion time 10 min) to 89.1% (digestion time 30 min). μPPMER can efficiently digest proteins due to the microscopic confinement effect, showing its potential application in fast protein identification and protease immobilization. Applications of on-line digestion using μPPMER with human plasma and urinary proteome samples showed that the developed on-line method yielded equivalent or better performance in protein coverage and identified more membrane proteins than the in-solution method. This may be due to easy accommodation of hydrophobic membrane proteins within membrane pores.

Structure and Properties of Deformed Aliphatic Polyesters

K. Nakayama,K. Qi,Y. Kodama,K-j. Hong,L. C. ter Beek 한국소성가공학회 1998 플라스틱가공 심포지엄(한일 공동 세미나) Vol.1998 No.9

Control of transposon activity by a histone H3K4 demethylase in rice

Cui, X.,Jin, P.,Cui, X.,Gu, L.,Lu, Z.,Xue, Y.,Wei, L.,Qi, J.,Song, X.,Luo, M. National Academy of Sciences 2013 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.110 No.5