• 한국공작기계학회논문집
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• 제17권4호
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• pp.81-88
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• 2008

Flow characteristics have one of the effects in the process of engine. The numerical analysis makes it possible to predict the flow fields. This paper presents characteristics of steady flow according to variation of valve lift in a gasoline engine. The numerical computations have been made to observe the pressure distribution in accordance with the variable valve lift. Characteristics of tumble flow and swirl flow according to the variable valve has also been investigated. We could find that tumble ratio and swirl ratio is different between with/without PDA valve. The steady flow test was simulated through three-dimensional analysis on intake port design for comparing with experimental data and confirming the feasibility of applying analytic method. As a result, this study shows the possibility of the usage of numerical simulation to predict the flow characteristics for gasoline engine.

• 한국공작기계학회논문집
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• 제15권4호
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• pp.74-82
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• 2006

This paper describes the steady flow characteristics due to PDA and tumble control valve in combustion chamber. We also investigated the flow inclination angle defined as the inverse tangent of non-dimensional rig tumble(NRT) devided by non-dimensional rig swirl(NRS) to find dominant flow direction. So we adapted two different types of PDA valve(port deactivation valve) to strengthen a swirl flow. The in-cylinder swirl flow different tendency between with/without PDA valve. It might be thought to be affected by swirl flow. We could find that tumble ratio and swirl ratio is different by PDA valve. The comparison are taked account of the swirl, the tumble ratio comparison in same mass flow rate. As a result, PDA valve is better than tumble control valve both in steady flow condition and swirl, tumble ratio. The data from present study are available for design of engine as the basic data.

• 한국공작기계학회논문집
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• 제13권3호
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• pp.104-112
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• 2004

The Swirl is one of the important parameters that effects the characteristics of combustion. PDA valve has been developed to satisfy two requirements of achieving sufficient swirl generation for improving the combustion and still maintaining high volumetric efficiency. This paper presents the experimental results of the effect of PDA valve on characteristics of combustion in single cylinder spark ignition engine. As a result, the combustion stability can be greatly improved by PDA valve. The data from present study are available for design of engine as the basic data.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1298-1307
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• 2001

Recently, the efforts to improve fuel economy and to reduce pollutant emission have become the main subject in the development of a gasoline engine. A lean combustion engine admitted as the best alternative is relatively lower fuel consumption rate and exhaust emissions. In this study, it is focused on intensifying intake flow field as one of methods to improve the performance of the lean combustion. First, three different types of suitable swirl control valve(SC7) with high swirl and tumble ratio are selected through steady flow experiment, being installed in a spark ignition engine. The relationship between lean misfire limit and torque was investigated with injection timing and spark ignition timing. Also, the effect of intensified swirl new on the combustion Stability and exhaust emissions was experimently examined by the measuring in-cylinder pressure and combustion variation. The results show that the engine with swirl control calve is superior to other conventional engine on the lean misfire limit, specific torque, combustion variation and emission, and the appropriate injection timing and spark ignition timing exist according to the type of swirl control valve.

• 한국공작기계학회논문집
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• 제14권4호
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• pp.32-40
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• 2005

The purpose of this study is to investigate variation of spark plug protrusion and PDA valve on the exhaust emission in a gasoline engine. Swirl is one of the important parameters that affects the characteristics of combustion. PDA valve has been developed to satisfy requirements of sufficient swirl generation for improving the combustion and reducing of emission level. Also, especially, the variation of spark plug protrusion have an important effect to the early flame propagative process. This is largely due to the high flame speed by short of flame propagation distance. So, this is forced that injection timing, spark timing and intake air motion govern the stable combustion. As a result, using two combustion chamber, without charge of engine specification and the variable spark plug location and PDA valve could be reduced exhaust gas at a part load engine conditions(1500rpm imep 3.9bar, 2000rpm imep 3.2bar, 2400rpm imep 3.9bar).

• 한국자동차공학회논문집
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• 제6권5호
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• pp.37-44
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• 1998

Lean burn combustion is an important concept for improving the fuel consumption and exhaust emissions. However, the lean burning is associated with increased cycle-to-cycle combustion variations due to the ignition instabilities and redu- ced flame propagation rates. Engine stability under lean mixture conditions could be improved by increasing flame speed through enhanced flow characteristics and by securing ignitability with improvement of ignition systems. The effects of flow motion and ignition characteristics on the combustion performances were investigated in a 4-valve SI engine. Flow motions of tumble-swirl were varied with a swirl control valve attached at the inlet ports, while ignition energy and its distribution were controlled in a high -frequency ignition system by changing spark duration and spark frequency. The improvement of lean burn performance by the optimum flow motion and ignition characteristics is discussed.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.57-64
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• 1999

Initial flame development and propagation were visualized under the new ignition system developed to estimate the effects of ignition characteristics on the engine performance in a port injection SI engine. Effects of intake air flow characteristics were also investigated by three different kinds of the swirl control valve. Experiments were performed in an optical single cylinder engine modified form a commercial engine. Flame images were captured through the quartz window mounted in the piston by the high speed video camera and analyzed to compare initial flame development. Results show that IMEP tends to rise slightly as the ignition duration gets longer. The direction of flame propagation is decisively governed by the in-cylinder flow motion. Every flame grows toward the exhaust valve forming a kind of turbulent flame. Initial flame propaagation characteristics are very similar to ones analyzed form pressure data.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.1-6
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• 2003

Natural gas is one of the promising alternative fuels because of the abundant deposits and the cleanness of emission gas. CNG has a lot of merits except lower burning speed has a slow disadvantage. One way to overcome the disadvantage is to raise a turbulence intensity. We give various intake for changing turbulence intensity in the cylinder by three kinds of swirl control valve with a way to raise a turbulence intensity. In the present study, a $1.8\ell$ conventional gasoline engine is modified to use a CNG as a fuel instead of gasoline. We try to virify combustion and emission characteristics in each engine parameters. Parameters of experimentation are equivalence ratio, spark timing and intake flow change. The results of this study are as swirl flows. In the case of adding swirl flow, burning speed and torque are increased. But NOx and THC concentration are increased a little respectively.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.80-86
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• 1996

In order to decrease fuel comsumption rate and emissions, lean burn engine which has equipped swirl control valve, is investigated experimentally on the test bench. Single cylinder engine was used to test the combustion and emission performance with 4 kinds of swirl valve. Decrease in the carbon monoxide, hyerocarbon and specific fuel consumption was shown at the lean condition, which means that a good choice of swirl valve on the given intake port geometry can be used to increase the combustion efficiency and lean limit.