• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.101-116
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• 2002

Modern vehicles require a high degree of refinement, including good driveability to meet customer demands. Vehicle driveability, which becomes a key decisive factor for marketability, is affected by many parameters such as engine control and the dynamic characteristics in drive lines. Therefore, Engine and drive train characteristics should be considered to achieve a well balanced vehicle response simultaneously. This paper describes analysis procedures using a mathematical model which has been developed to simulate spark timing control logic. Inertia mass moment, stiffness and damping coefficient of engine and drive train were simulated to analyze the effect of parameters which were related vehicle dynamic behavior. Inertia mass moment of engine and stiffness of drive line were shown key factors for the shuffle characteristics. It was found that torque increase rate, torque reduction rate and torque recovery timing and rate influenced the shuffle characteristics at the tip-in condition for the given system in this study.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.106-113
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• 2016

Lean burn engine, classified into port injection and direct injection, is recognized as a promising way to meet better fuel economy. Especially, LPG direct injection engine is becoming increasingly popular due to their potential for improved fuel economy and emissions. Also, LPDi engine has the advantages of higher power output, higher thermal efficiency, higher EGR tolerance due to the operation characteristics of increased volumetric efficiency, compression ratio and ultra-lean combustion scheme. However, LPDi engine has many difficulties to be solved, such as complexity of injection control mode (fuel injection timing, injection rate), fuel injection pressure, spark timing, unburned hydrocarbon and restricted power. This study is investigated to the influence of spark timing, fuel injection position and fuel injection rate on the combustion stability of LPDi engine. Piston shape is constituted the bowl type piston. The characteristics of combustion is analyzed with the variations of spark timing, fuel injection position and fuel injection rate (early injection, late injection) in a LPDi engine.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.89-93
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• 1989

In this paper, a mathematical engine model based on the actual engine operation is formulated to be adapted for the evalution and development of engine control system. In the model the classification of fuel paticle siza is considered. The model is simulated through the mathematical interpretation of intake manifold in the rapidly-accerated state. The spark-timing is analyzed with respect to engine r.p.m. The result shows that the model behaves similar performance to the actual engine operation and the spark-timing is very important to the characterization of engine r.p.m..

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.44-51
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• 2005

According to the increasing concern on the global environment, the $CO_2$ regulation has been discussed including automobile emission regulation. In order to cope with this rapid changing circumstances, the development of an ultra low emission and super fuel economy automobile is essential. Direct injection LPG engine is the one of the possible future engine to maximize the engine efficiency. This experimental study for the development of direct injection LPG engine technology is promoted with two parts; spray characteristics of high pressure swirl injector, and performance characteristics of direct injection LPG engine. Engine characteristics according to the fuel was analyzed in order to establish stratified combustion technology for LPG engine by using the DISI engine. In the engine experiment, control system was manufactured for gasoline and LPG fuel. The engine was modified 2,000 cc GDI engine (fuel supply device, fuel injection device). Through this experiment, engine operating condition, engine speed and spark timing (MBT), fuel injection position, and fuel rate were investigated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2361-2370
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• 2000

The introduction of inexpensive cylinder pressure sensors provides new opportunities for precise engine control. This paper presents a control strategy of spark advance based upon cylinder pressure of spark ignition engines. A location of peak pressure(LPP) is the major parameter for controlling the spark timing, and also the UP is estimated, using a multi-layer feedforward neural network, which needs only five pressure sensor output voltage samples at -40˚, -20˚, 0˚, 20˚, 40˚ after top dead center. The neural network plays an important role in mitigating the A/D conversion load of an electronic engine controller by increasing the sampling interval from 10 crank angle(CA) to 20˚ CA. A proposed control algorithm does not need a sensor calibration and pegging(bias calculation) procedure because the neural network estimates the UP from the raw sensor output voltage. The estimated LPP can be regarded as a good index for combustion phasing, and can also be used as an MBT control parameter. The feasibility of this methodology is closely examined through steady and transient engine operations to control individual cylinder spark advance. The experimental results have revealed a favorable agreement of individual cylinder optimal combustion phasing.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.23-31
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• 2000

Knock and misfire, kinds of abnormal combustion, are highly undesirable effect on the internal combustion engine. So, it is important to detect these avnormal combuition and control the ignition timing etc. to avoid these mal-effect factors in real engine system. In this study, the system which detects the knock and the misfire using by spark plug is presented. This system is based on the effect of modulation breakdown voltage(BDV) between the spark gaps. The voltage drop between spark plug electrodes, when an electrical breakdown is initiated, depends on the temperature and pressure in combustion chamber. So, we can detect knock and misfire that produce changes in gas temperature and pressure (consequently, its density) using by BDV signal change which carries information about the character of combustion.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.22-35
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• 1995

In this paper, an electronic control unit is developed using 16bit microcomputer for automobile engine. This system incorporate AFS(Air Flow Sensor) of Hot Wire type, DIS(Direct Ignition System), ISC(Idle Speed Control) system, CAS(Cranke Angle Sensor) and other peripheral device. This system includes hardware and software to facilitate precision control of both fuel injection and ignition timing. Especially, this controller consists of position signal(180 teeth) and 4 REF signals. Present system has maximum $720^{\circ}CA$ delay. But this system has maximum $180^{\circ}CA$. Thus, this system is able to precision control both fuel injection and ignition timing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.10
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• pp.1163-1171
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• 2004

The variation of spark plug location have one of the effects on combustion characteristics. Several parameters of the effect on combustion characteristics are shape of combustion chamber, the spark plug position, turbulence flow and so on. This paper presents an experimental study according to variation of spark plug protrusion and PDA valve which have effects on characteristics of combustion and emission in single cylinder gasoline engine. Also, this paper emphasized that combustion stabilization was making by way of the reinforcement of the turbulent flow with the PDA valve. A feasibility and necessity of combustion pressure based cylinder spark timing control according to spark plug protrusion has been examined. So, this was obtained COV$\_$imep/ and the mass fraction burned(MFB) and the specific fuel consumption(sfc). Using the results of the test, the effects of the variable spark plug location and PDA valve can be improved fuel consumption and be available for the combustion stability.

• Journal of Biosystems Engineering
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• v.14 no.2
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• pp.80-84
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• 1989

In order to improve the combustion efficiency of the agricultural engine, an ignition timing control system was developed and tested. The control system was composed of the CDI ignition circuit, the microcomputer and the interfacing devices. In this study, the simplicity of the control system and the flexibility of the control strategy were emphasized for the precision, the applicability and the economical efficiency. The hardware was consisted in almost the same compositions as those of the automobile engine. The softwares of the control algorithms were developed to three types depending on the combination of the quasi-adaptive control and the open loop control which had the different spark advance equations according to the input variables such as engine speed, exhaust gas temperature and brake torque. The test results were summarized as follows: 1. By using the computer control system, the fuel consumption efficiency could be improved and the fuel consumption could be reduced by 0 to 57% compared to that of the fixed spark advance system. 2. The fuel consumption of the control mode with the quasi-adaptive algorithm was reduced by average 0.8% compared to that of the control mode without quasi-adaptive algorithm. 3. It was found that the control mode with the quasi-adaptive algorithm adopting single input of engine speed had most applicability and economical efficiency among three types of the control algorithms.