Development of a DI-Diesel Engine with Four Valves for Passenger Cars

Herrmann, Hans-Otto; Dürnholz, Manfred

doi:10.4271/950808

Cited by 13 publications

(4 citation statements)

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“…In recent years, high-speed DI diesel engines with four valves per cylinder are becoming widely used [1][2][3][4][5] . Compared with conventional two valve engines, four valve DI diesel engines have higher volumetric efficiency and lower pumping loss.…”

Section: Introductionmentioning

confidence: 99%

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miR-27a regulates the self renewal of the H446 small cell lung cancer cell line in vitro

Miao

Qiu

et al. 2012

Oncology Reports

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Cancer growth is driven by cancer stem-like cells within a tumor, called cancer stem cells (CSCs). Since miRNAs can regulate cell-fate decisions, we compared miRNA expression in stem-like cells and differentiated cells from small cell lung cancer (SCLC) cell lines to develop further understanding of the molecular mechanisms involved in the pathogenesis of SCLC. First, SCLC stem-like cells were enriched by isolating sphere-forming cells using a deﬁned serum-free medium. Further, microRNA microarrays were used to measure the expression of 1212 miRNAs in sphere-forming cells and parental cells. We found 86 miRNAs that were differentially expressed, including 48 upregulated miRNAs and 38 downregulated miRNAs between sphere-forming cells and parental cells. Among them, five downregulated miRNAs (let-7, miR-20, 21, 27a and 30b) and one upregulated miRNA (miR-149*) were selected for validation in 3 sets of SCLC cell lines by qRT-RCR. The qRT-PCR analysis confirmed that all six miRNAs were indeed differentially expressed. However, only miR-27a was consistently downregulated in sphere-forming cells of all 3 cell lines. Antagonizing miR-27a by inhibitor in parental cells enhanced proliferation, self renewal, and the proportion of undifferentiated cells in vitro. The candidate miRNA and some miRNAs with same seed sequence are predicted to have several target genes related to apoptosis, cell proliferation and cell cycle. Our results suggest that downregulation of miR-27a enhanced the stem-like properties of SCLC cells in vitro and may be critical to maintaining a stem cell function in SCLC.

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Section: Introductionmentioning

confidence: 99%

“…In fact, the geometry of intake ports in production four valve engines is very complex due to different configuration of cylinder head [1][2][3][4][5] . It is almost impossible to understand the effect of the shape of intake port on flow characteristic through simple tests.…”

Section: Introductionmentioning

confidence: 99%

miR-27a regulates the self renewal of the H446 small cell lung cancer cell line in vitro

Miao

Qiu

et al. 2012

Oncology Reports

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“…A first important result yielded by three-dimensional CFD simulations is the intensity of tumble motion at EPC, comparable or even superior to the strength of swirl vortexes typical of conventional chambers in both two-and four-stroke DI diesel engines [4,[16][17][18][19]. Furthermore, the tumble intensity at EPC is almost independent of the pressure ratio across the cylinder.…”

Section: The Scavenging Processmentioning

confidence: 99%

Virtual design of a novel two-stroke high-speed direct-injection diesel engine

Mattarelli

2009

International Journal of Engine Research

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The paper reviews the virtual design process of an automotive high-speed direct-injection (HSDI) two-stroke diesel engine, developed at the Department of Mechanical and Civil Engineering (DIMeC) of the University of Modena and Reggio Emilia. The new concept of the engine is the tumble-supported and spray-controlled combustion system, which enables the adoption of loop scavenging without valves, and the use of a very simple and compact combustion chamber, carved in the engine head. The concept has been applied to a three-cylinder engine, with a capacity of 1050 cm3, supercharged by means of a Roots compressor and a variable geometry turbocharger. Some alternative configurations have been defined. Integrated one-dimensional and multidimensional computational fluid dynamics (CFD) simulations have been performed in order to optimize the main engine parameters, as well as to predict brake performance and emissions, in comparison with a reference four-stroke automobile diesel engine. Simulation results demonstrate the potential of the concept, which may be applied to develop a new generation of ultra-compact and clean automotive diesel engines.

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“…Moreover, the higher swirl ratio enhances the heat transfer losses, consequently decreasing the thermal efficiency [19]. Thus, with high fuel injection pressure, the relatively low swirl ratio is pre ferred in new diesel engine developments [20]. In this paper, YC6J105 diesel engine, which has low swirl ratio, was chosen to investigate the effect of the casting and machining deviations on engine in-cylinder flow characteristics.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Modeling Study of the Effect of Manufacturing Deviations on the Flow Characteristics of Tangential Intake Port in a Diesel Engine

Wang

Liu

et al. 2014

Journal of Engineering for Gas Turbines and Power

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The intake port flow characteristics in an internal combustion engine significantly affect its power output, fuel economy, and emissions. To optimize the flow characteristics in the intake port, increasing attention has been paid to its design process. However, the casting and machining processes of the intake port are underappreciated, which may introduce significant deviations, leading to undesirable variation of intake port flow and subsequent deterioration in engine combustion and emissions. In this paper, steady flow tests were carried out on a four-valve diesel engine to investigate how and to what extent the casting and machining deviations of the intake port influence the in-cylinder flow characteristics. The results show that these deviations lead to the variation of swirl ratio up to 20%. Then, computational fluid dynamics (CFD) simulation was conducted for understanding the reason. It is indicated that higher tolerance is needed during the cast ing and machining processes. For example, in order to control the variation o f swirl ratio within 10%, the inclined angle should be controlled at less than 1 deg, the eccentric dis tance should be restricted to less than 0.5 mm, and the swelling thickness should be lim ited to less than 1 mm.

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Development of a DI-Diesel Engine with Four Valves for Passenger Cars

Cited by 13 publications

References 1 publication

miR-27a regulates the self renewal of the H446 small cell lung cancer cell line in vitro

miR-27a regulates the self renewal of the H446 small cell lung cancer cell line in vitro

Virtual design of a novel two-stroke high-speed direct-injection diesel engine

Experimental and Modeling Study of the Effect of Manufacturing Deviations on the Flow Characteristics of Tangential Intake Port in a Diesel Engine

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