• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.682-687
• /
• 2001

This study represents effect of exhaust performance by according to active muffler valve spring. The experimental parameter were divided engine speed and torsion coil spring constant. The sound pressure level was generally low at engine speed 2000-2500rpm but That was showed the lowest at spring constant k=0.75. Flow speed of exhaust gas was showed the fast at spring constant k=0.75 but the low value was showed at k=0.97. It was contained a rather low concentration of carbon monoxide(CO) at engine speed 2000-2500rpm and k=0.81, low concentration of hydrocarbon(HC) at spring constant k=0.81 but that was high at spring constant k=0.97. A conclusion based on FFT analysis was generally low concentration value at k=0.79 and k=0.81. The temperature distributions into the muffler was shown similar conditions. Heat transfer was well spreaded at thermocouple No.8 because valve was opened.

• Journal of the Korean Institute of Gas
• /
• v.19 no.6
• /
• pp.110-115
• /
• 2015

In this paper it is proposed to solve the problem of particulate matter reducing apparatus of the current DPF. One exhaust gas passage 2-way controlled to purify the exhaust gas generated during combustion efficiently. Through the control of the rotary valve within a single device, it is possible to prevent the exhaust pressure increases due to particulate matter accumulate inside the developing DPF. Develop DPF device capable of inducing a high efficiency of the output in order to improve the problem of reducing the engine output and fuel efficiency.

• Journal of ILASS-Korea
• /
• v.27 no.2
• /
• pp.94-100
• /
• 2022

Even in non-road UTV (Utility Terrain Vehicle), spark ignition engines are often used to reduce emissions. In this study, gasoline and LPG (Liquified Petroleum Gas) fuels were applied to UTV engines, and the exhaust gas and combustion stability were compared through engine tests. A 0.8-liter two-cylinder SI engine was used in the experiment. Experiments were conducted while changing the IVO (Intake Valve Open) and EVC (Exhaust Valve Close) at 1500 rpm 14 N·m, 40 N·m, and 3000 rpm 17 N·m, 44 N·m conditions. As a result of the experiment, when the valve overlap increased according to the change of IVO and EVC, combustion stability decreased and THC emission increased, but NOx decreased. Comparing the LPG engine with the gasoline engine, the amount of CO₂ and PN (Particulate Number) generation decreased in the LPG engine, and the combustion stability was good.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.5
• /
• pp.37-42
• /
• 2003

This research was carried on an 8100cc turbo-charged heavy duty diesel in the application of a cooled-EGR. Exhaust and intake manifold were modified and an electronically controlled EGR was installed in order to investigate engine performance and exhausted emission characteristics. High pressure route was designed in the compact form on the purpose of practicability in this cooled-EGR system, which constitutes a venturi tube to maintain pressure difference between exhaust manifold and compressor, an EGR cooler, an EGR valve and a solenoid valve.

• Journal of the korean Society of Automotive Engineers
• /
• v.13 no.3
• /
• pp.25-31
• /
• 1991

The formation process of hydrocarbon emissions was investigated in SI engine. The time- resolved concentrations of hydrocarbon emissions were measured using a high gas sampling valve and a gas chromatography. The gas was sampled at exhaust port, or the position of spark plug, or the wall of combustion chamber. The experiments were conducted using the Alpha engine of Hyundai Motor Company. The fuel used was methanol or propane. It was found that the effect of the quenching layer of combustion chamber wall on hydrocarbon emissions was not significant. The increasing rate of hydrocarbon concentration at combustion chamber wall near crevice and oil layer after flame was reached was much higher than that at the position of spark plug. The hydrocarbon concentrations at exhaust port had two peak values just after opening exhaust valve and just before closing it.

• Journal of Advanced Marine Engineering and Technology
• /
• v.20 no.3
• /
• pp.74-81
• /
• 1996

The wave washer springs are widely used in non-return valves of fluid, especially in air check valves to confirm the rapid shut-off of valve propers. The stiffness of wave washer springs used in suction and exhaust valves of reciprocating air compressor play an important role on efficiency of the compressor. If the stiffness of the spring is too high, the pressure differences necessary to open the valves become high and the volumetric efficiency of cylinder decreasse. If the stiffness of the spring too low, the valve can not be closed rapidly and the inverse flow of air can take place. So, the optimum stiffness of valve spring is very important and it will be very helpful that the stiffness of wave washer springs to be used in suction and exhaust valves can be calculated in design stage of air compressor. In this paper the formula for calculating the spring constant of wave washer spring is introduced using bending and torsion theory of frames. The experiments are also carried out to measure the spring constants of several samples. It is proven that the calculated spring constants of wave washer springs are coincided well with measured values and that the formula presented in this paper for calculating the spring constants of wave washer spring is very useful for design of valves used in reciprocating air compressor.

• Journal of the Korean Society of Visualization
• /
• v.19 no.1
• /
• pp.62-67
• /
• 2021

Selective catalytic reduction(SCR) is an exhaust gas reduction device to remove nitro oxides (NOx). SCR operation of ship can be controlled through valves for minimizing economic loss from SCR. Valve in SCR-high pressure (HP) system is directly connected to engine exhaust and operates in high temperature and high pressure. Long-term thermal deformation induced by engine heat weakens the sealing of the valve, which can lead to unexpected failures during ship sailing. In order to prevent the unexpected failures due to long-term valve thermal deformation, a failure prediction system using autoregressive integrated moving average (ARIMA) was proposed. Based on the heating experiment, virtual data mimicking temperature range around the SCR-HP valve were produced. By detecting abnormal temperature rise and fall based on the short-term ARIMA prediction, an algorithm determines whether present temperature data is required for failure prediction. The signal processed by the data collection algorithm was interpolated for the failure prediction. By comparing mean average error (MAE) and root mean square error (RMSE), ARIMA model and suitable prediction instant were determined.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.1
• /
• pp.45-51
• /
• 2015

In order to meet the enforced emission regulations and reduce fuel consumption, various new technologies are employed in engines. The problem of NOx emissions under a lean mixture condition should be solved, because a lean-burn direct-injection engine can realize stable lean combustion with a stratified mixture, which results in improvements in fuel economy and emissions. This study investigated the effects of intake and exhaust valve timing changes on the performance and emission characteristics of a lean-burn LPG direct-injection engine. Under a partial-load operating condition without throttling, an increase in the intake valve opening led to an increase in NOx emissions due to an increase in the amount of excess air. The fuel consumption deteriorated with an increase in the exhaust valve opening due to a decrease in the expansion work and an increase in the pumping loss.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.5
• /
• pp.37-44
• /
• 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.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.928-933
• /
• 2001

EGR(Exhaust Gas Recirculation) is an effective strategy to control nitrogen oxides emissions from diesel engine. The EGR reduces $NO_x$ through lowering the oxygen concentration in the combustion chamber as well as through heat absorption. However, application of EGR system is difficult because of the penalty in fuel consumption and the increase in particulate matter. The engine used for the experimental was a 3-cylinder 0.8-liter turbo-charged light duty diesel engine with an electronic EGR valve. In this study, experiments were performed at variable vehicle speeds and loads on the chassis dynamometer. To evaluate the exhaust emissions with the EGR system testing was performed using cvs-75 mode test procedure. Results of the cvs-75 mode test achieve sufficiently to meet EURO3 standards.