• International Journal of Fluid Machinery and Systems
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• v.9 no.4
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• pp.332-337
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• 2016

Turbocompounding is a key technology to satisfy the future requirements of diesel engine's fuel economy and emission reduction. A turbocompound diesel engine was developed based on a conventional 11-Liter heavy-duty diesel engine. The turbocompound system includes a power turbine, which is installed downstream of a Variable Geometry Turbocharger (VGT) turbine. The impacts of the VGT rack position on the turbocompound engine performance were studied. An optimal VGT control strategy was determined. Experimental results show that the turbocompound engine using the optimal VGT control strategy achieves better performance than the original engine under all full load operation conditions. The averaged and maximum reductions of the brake specific fuel consumption (BSFC) are 3% and 8% respectively.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.680-686
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• 2004

Recently, the application of variable geometry turbocharger (VGT) to the high speed direct injection (HSDI) diesel engine has gained more and more interest in automotive industry. A steady state experimental investigation has been undertaken on a 1.5L HSDI diesel engine to verify the benefits of VGT comparing to the standard engine having a waste gate turbocharger (WGT). Specifically, part load performances (e.g., fuel economy and emission) have been investigated under various vane angles of the VGT. The results show that the real exhaust gas recirculation (EGR) rate as well as the pumping loss is very important to improve break specific fuel consumption (BSFC). It was previously known that the pumping loss only is a main parameter. In addition, the trade-off relationship between BSFC and NOx according to boost pressure, and the decreasing tendency of NOx with increasing real EGR rate have been verified. 1-D numerical analysis also has been performed, and the numerical results are in good agreement with experimental results.

• Journal of the Korean Society of Combustion
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• v.21 no.4
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• pp.1-5
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• 2016

The aim of this study is to compare the effectiveness of turbo chargers on engines for off-road use when combined with WGT and VGT technologies. The effectiveness of turbo chargers was measured and performance was compared using a functional model. Exhaust characteristics were compared using WGT and VGT technologies through a gas analyzer. Results showed VGT technology was more effective at high RPM compared to WGT technology. When it came to maximising turbo performance, VGT was more effective than WGT in every test. WGT and VGT produced similar exhaust NOx levels, whereas the VGT was more effective on the PM.

• Journal of the korean Society of Automotive Engineers
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• v.27 no.2
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• pp.94-100
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• 2005

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.65-73
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• 2007

The use of an Exhaust Gas Recirculation(EGR) for a diesel engine with variable geometry turbocharger(VGT) has confronted how to obtain the amount of EGR for NOx reduction requirement at wide operating range and less side effect. Through a combined effort of modeling(wave action simulation) and experiment, an investigation into the effect of EGR area ratio and pipe length on EGR characteristics of common rail diesel engine with VGT has been performed. For accurate computation, calibration of constants involved in empirical and semi-empirical correlations has been performed at a specific operating point, before of its use for engine simulation. From the results of this study, it was found that EGR rate is sharply increased with increasing EGR area ratio until area ratio of 0.3. However, the effect of EGR area ratio on EGR rate is negligible beyond this criteria. This study also investigates the effect of EGR pipe length on a EGR amount and pulsating flow characteristics at EGR junction. The results showed that the longer EGR pipe length, the lower EGR amount was achieved due to the flow loss resulting in lower amplitude of pressure wave.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.8
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• pp.783-790
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• 2010

In this paper, we propose a turbine mass flow rate model for a variable geometry turbocharger (VGT) using an artificial neural network (ANN). The model predicts the turbine mass flow rate using the VGT vane position, engine rotational speed, exhaust manifold pressure, exhaust manifold temperature, and turbine outlet pressure. The ANN is used for the estimation of the effective flow area. In order to validate the results estimated by the proposed model, we have compared estimation results with engine experimental results. The results, in addition, represent improved estimation accuracy when compared with the performance using the turbine map.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.182-189
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• 2014

This paper proposes a decoupler design method to reduce interaction between exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT) systems in passenger car diesel engines. The EGR valve and VGT vane are respectively used to control air-to-fuel ratio (AFR) of exhaust gas and intake pressure. A plant model for EGR and VGT systems is defined by a first order transfer function plus time-delay model, and the loop interaction between these systems is analyzed using a relative normalized gain array (RNGA) method. In order to deal with the loop interaction, a design method for simplified decoupler is applied to this study. Feedback control algorithms for AFR and intake pressure are composed of a compensator using PID control method and a prefilter. The proposed decoupler is evaluated through engine experiment, and the results successfully showed that the loop interaction between EGR and VGT systems can be reduced by using the proposed decoupler. Furthermore, it presents stable performance even off from the designed operating point.

• Journal of the Korean Society of Combustion
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• v.21 no.2
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• pp.1-6
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• 2016

To meet the Tier-4 emission standard, a variety of combustion technology in the field of off-road engine has been applied in conjunction with the engine after treatment technology. In this study, as the basis study for applying VGT and HPL EGR to 3.6 L CRDi engine, exhaust gas characteristics and fuel economy characteristics are confirmed in accordance with VGT and EGR operating conditions. Consequently, in the EGR applicable conditions, 60% VGT vane duty condition was confirmed that the trade-off characteristics between NOx and smoke are advantageous. In addition, in view of BSFC, VGT vane duty is considered desirable to control at around 50%.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.159-164
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• 2008

In diesel engine technology the drive to reduce emissions and fuel consumption with improved performance targets has led to many advances. In particular, Exhaust Gas Recirculation (EGR) and Variable Geometry Turbocharger (VGT) have played a key role in achieving these aims by permitting flexible control of the engine inlet gas charge. The full potential of these devices are difficult to achieve due to limitations in the classical control methods. However, fuzzy logic is particularly appealing due to its simple heuristic nature. The controller used in this work was designed using the Matlab Fuzzy Logic Toolbox. The overall object is to access the potential for emissions and fuel consumption reductions during transient events whilst maintaining and even improving driveability. Classical control methods (PID), as used on production engines, are examined and contrasted with an coordinated control that utilizes fuzzy logic.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.127-132
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• 2009

The transient performance of the passenger diesel engine equipped with the variable geometry turbocharger was simulated using HIL(hardware-in-the-loop) system. The system consists of engine model as software, and the turbocharger test bench as hardware. The engine model is mean value model which is programmed by the Simulink of the Mathworks. The turbocharger test bench is composed of a blower, some sensors, and DAQ boards. A real time simulation is possible since the operating system based on the real time is included. The results show the good response for the transient characteristics. Therefore this HIL system can be used for development of the new turbocharger effectively.