• Journal of the korean Society of Automotive Engineers
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• v.5 no.3
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• pp.33-44
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• 1983

This paper deals with the experimental study on the behavior of fuel (methanol) in intake manifold by using the basic apparatus which is manufactured the visible straight tube type model. In this study, the new device for liquid film thickness measurement and vaporization rate measurement are introduced to investigate the variation of liquid film thickness along the intake manifold and to observe the effect of vaporization of injected fuel. the results are summarized as follows: 1) The vaporization rate increases in proportion to decreasing of throttle valve angle and growing air fuel ratio. 2) The liquid film thickness along the intake manifold is mostly independent for the throttle valve angle in low air velocity and then affected in high air velocity, but the distribution of the liquid film thickness on circumferential position almost constant in the region of 300mm down stream from carburetor. 3) The mean liquid film thickness is 0.04 - 0.18mm in case of methanol in the region of air velocity Va = 12m/s - 55m/s and decreases with decreasing the throttle valve angle.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.5
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• pp.388-397
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• 2001

This paper addresses characteristics of compressible flow dynamics inside a pipe with an accumulator and an inlet orifice. It also presents a simple but stable numerical method associated with the accumulator-orifice calculation. In particular, a focus is given to developing a method of finding an optimum design of the accumulator-orifice system (i.e., the accumulator size and the throttle resistance) that gives the most effective dissipation of the water-hammering problem. It is found that there exists indeed an optimum set of parameter values for the most effective dissipation of the wave energy.

• Journal of ILASS-Korea
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• v.19 no.2
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• pp.64-68
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• 2014

A driving vehicle performance which is driven by FTP-75 mode was simulated by computer. Throttle valve position, engine speed, air mass flow rate, fuel consumption et al. were computer simulated. A set of engine part load performance data, automatic transmission shift map and vehicle specifications were used for the computer simulation. Throttle valve position, engine speed, air mass flow rate et al. measured for evaluating the computer simulation results by driving the vehicle with FTP-75 mode on a chassis dynamometer. GT-Power$^{(R)}$ software was used for the computer simulation of the driving vehicle performance. Experimental fuel consumption rate was measured by using an ECU HILS fuel injection system. The experimental data and simulation results were compared. The computer simulation of the driving vehicle performance predicts the measured data well comparatively.

• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.286-293
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• 2004

The air fuel ratios of current gasoline engines are almost controlled by several air flow meters. When CVVT (Continuous Variable Valve Timing) is applied to a gasoline engine for higher engine performance, the MAP (Manifold Absolute Pressure) sensor is difficult to follow the instantaneous air fuel ratio due to the valve timing effect. Therefore, a HFM (Hot Film Flow Meter) is widely used for measuring intake air flow in this case. However, the HFMs are incapable of indicating to reverse flow, the oscillation of intake air flow has an negative effect on the precision of the HFM. Consequently, the various duct configurations in front of the air flow sensor affect the precision of HFM sensitivity. This paper mainly focused on the analysis of the reverse flow, flow fluctuation in throttle upstream and the geometry of intake system which influence the HFM measurement.

• Journal of ILASS-Korea
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• v.14 no.1
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• pp.34-38
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• 2009

This paper presents the pulsation of carburetor inlet and outlet pressure of a small SI gasoline engine. The engine used in this paper is a 23cc, single cylinder, diaphragm carburetor, two-stroke, air-cooled for brush cutter. The rpm and pressure wave pulsation at the inlet and the outlet of carburetor were measured and analysed for the understand of the internal air flow into the barrel on the diaphragm carburetor. These data should be used for the development of the duel fuel injection system for gasoline and LPG. The results showed that the carburetor inlet pressure variations were very steady, but the pressure variations at carburetor outlet were very sensitive to the pressure variation into the crank case and were to similar independently to the engine speed on partial opened throttle conditions. According to increasing engine speed, the pressure waves started to come out and be developed after closing the intake port of the engine at carburetor outlet. Reverse flow occurred on the WOT (wide open throttle) condition.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1184-1189
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• 1990

In order to investigate liquid fuel filming over the intake manifold wall, an electrode-type probe has been developed by lines of authors and this probe was employed in a single cylinder two and four-stroke cycle engine and in a four cylinder four-stroke engine operated by neat methanol fuel. The performance of the probe was dependent upon several parameters including the liquid fuel layer thickness, temperature, additive in the fuel, and electric power source (i.e., AC and voltage level) and was independent of other variables such as direction of liquid flow with respect to the probe arrangement. Several new findings from this study may be in order. The flow velocity of the fuel layer in the intake manifold of engine was about (if the air velocity in the steady state operation, the layer thickness of liquid fuel varied in both the circumferential and longitydinal directions. In the transient operation of the engine, the temporal variation of fuel thickness was determined, which clearly suggests that there was difference between fuel/air ratio in the intake manifold and that in the cylinder. The variation was greatly affected by the engine speed, fuel/air ratio and throttle opening. And the variation was also very significant from cylinder to cylinder and it was particularly strong different engine speeds and throttle opening.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.58-65
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• 1995

In this study an air flow meter was developed for MPI engine using ultrasonic sensors. The major characteristcs of the ultrasonic flow meter are high speed response, flow direction recognition and linear output. The air flow rate measurements were conducted at upstream of the throttle and intake manifold. The characteristics of the ultrasonic flow meter are compared with those of the Bosch hot wire flow meter at both steady and unsteady engine conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.110-118
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• 2008

It is essential for the valid design of a marine flow-control valve to exactly know its flow characteristics. The present study has numerically investigated the flow characteristics inside a marine throttle-type globe valve using a kind of commercial CFD code, CFX10.0, with an adoption of the SST (Shear-Stress Transport) turbulence model. To validate the numerical approach, the flow coefficients are compared with the experimental ones. Results show that the globe valve is effective in the control of flow rate according to the opening ratio in case of the forward-direction flow, whereas it is effective in the flow shutoff in case of the reverse-direction flow. Around the inlet of the valve, a recirculation region is formed due to the blunt body shape, the turbulence intensity becomes strengthened and then an abrupt pressure loss occurs.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.151-157
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• 1999

In this paper, an integrated nonlinear sliding mode observer and controller has been designed in order to control of an automotive engine idle speed. The primary objective of the engine idle speed control is to maintain the desired engine idle speed despite of various torque disturbances via estimating air mass flow at the location of the injector in intake manifold by using a sliding mode observer. Simulation results show that the case where both throttle angle and ignition time are used as control inputs outperforms the case where just only throttle angle is used as a control input.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.218-228
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• 1996

The behaviors of the mixture at the downstream of throttle valve in a TBI type gasoline engine plays a greater role in design of intake system. A good mixture has been influencing directly not only on the engine power but also on the pollutant emission. The mixture flow in an intake manifold is very complex, and the flow characteristics are varied with the valve type, valve angle, inlet air flow rate, and the other flow factors. Three kinds of valve are chosen in this study, and the informations of the mixture flow are observed experimentally using a PIV apparatus. Perforate valve has a smaller recirculation zone than the case of solid valve with a lower valve loss coefficient, and iti is verified that the perforated valve is also suitable to control the flow rate in a mixture flow system.