• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.61-66
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• 2012

Conventional method to transform vehicle driving condition to engine operation mode is to use vehicle road load under neutral gear and mechanical efficiency of drivetrain. But this method requires additional measurement of efficiency of drivetrain on a test rig. And this measurement is normally done at fixed speed and thus estimated accuracy of engine operation mode is not considered to be high enough. This study suggests new method to calculate engine operation mode for prescribed driving mode such as NEDC using vehicle coastdown test under gear engaged condition without measurement of mechanical efficiency of drivetrain. Coastdown test was done under neutral and gear engaged condition for comparison and also trial to extract mechanical loss of drivetrain was carried out. Calculated engine torque by conventional and newly suggested method was compared with actually measured torque of a vehicle on a chassis dynamometer during NEDC. Newly suggested method showed slightly higher accuracy of accumulated brake work during NEDC.

• Journal of Institute of Convergence Technology
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• v.8 no.1
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• pp.5-8
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• 2018

Emissions of diesel vehicles have been regulated by NEDC mode for a long time. However, the NEDC mode has been known the control of emission reduction is not reflected properly on actual road conditions. For these reasons, diesel vehicle emissions are regulated in both NEDC mode and WLTC mode from 2017 to 2020, from 2020 onwards, the emissions of diesel vehicles will measure in WLTC mode only and will not be able to exceed 1.5 times the regulated value. The purpose of this study is to analyze the development trend of diesel vehicle after-treatment system in order to comply with the future regulations on diesel vehicle. As a result, it is essential to reduce the NOx emissions of diesel vehicles for Euro 6, the NOx emissions of the test vehicle equipped with SCR were 30% to 50% loss than the test vehicle equipped with LNT despite the higher curb weight and engine displacement.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.2
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• pp.81-87
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• 2015

LP(low pressure)-EGR system was investigated to evaluate its potential on fuel economy improvement and NOx emission reduction in a diesel engine. A diesel engine was tested for the evaluation of LP-EGR system at both of steady-state and transient test. For a transient test, control logic for LP-EGR valve operation was developed and a NEDC mode test was conducted by using a vehicle status simulation test. The steady-state results showed that LP-EGR system can reduce more NOx emission or fuel consumption comparing to the conventional HP(high pressure)-EGR. From the NEDC mode test, this LP-EGR system showed a possibility to improve fuel economy without a penalty of emissions.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.34-39
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• 2015

Recently, most of the energy consumed in vehicle is derived from fossil fuels. For this reason, the demand for clean, renewable and affordable alternative energy is forcing the automotive industry to look beyond the conventional fossil fuels. Natural gas represents today a promising alternative to conventional fuels for vehicles propulsion, because it is characterized by a relatively low cost, better geopolitical distribution than oil, lower environmental impact, higher octane number and a higher self ignition temperature. Above all, CNG is an environmentally clean alternative to the existing spark ignition engines with the advantages of minimum change. In this study was installed bi-fuel system that a conventional 2 liters gasoline engine was modified to run on natural gas by a gas injection system. Experiments were mainly carried on the optimization of an ECU control strategy affecting the emission characteristics of CNG/Gasoline bi-fule vehicle. The test results shown that CO2 emission in bi-fuel mode was reduced 16% compared to gasoline fuel in the NEDC mode. Also the amount of CO and HC emissions in bi-fuel and gasoline modes were found to equality. But Compared to gasoline, the bi-fuel mode resulted in higher NOx emissions.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.114-120
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• 2008

Recently, the nano-PM's number concentration emitted by diesel internal combustion engine has focused on attention because this particulate matters are suspected being hazardous of human health. In this study, The nano-PM mass and size of diesel passenger vehicles were measured on chassis dynamometer test bench. The particulate matters(PM) emissions of these vehicles were investigated by number concentration too. A condensation particle counter(CPC) system was applied to measure the particle number and size concentration of diesel exhaust particles at the end of dilution tunnel along the NEDC(ECE15+EUDC) and CVS-75 vehicle test mode. As the research result, the characteristic of vehicle test mode on the diesel nano-particle number and size distribution was investigated in this study.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.77-83
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• 2014

As the interest on the air pollution is gradually risen up at home and abroad, their vehicle emission regulations have been reinforcing by steps. PM regulation was also reinforced 4times for the last 13years and has been applied to SI vehicles after EURO 5. Additionally, knowing that small particles of PM can easily penetrate deep into lungs PM number was added on the regulation from EURO5+ and is applied to CI vehicles. Also, PN regulation is going to be applied to SI vehicles. But, because the regulation is appled to only a general test mode of each countries that is performed at $25{\pm}5^{\circ}C$, it is unclear whether the regulation can work on the other ambient temperature conditions or not. In this paper, to know that exhaust emission characteristics at the special conditions CI vehicles(CRDi w, w/o DPF) were tested using 5-cycle mode, NEDC mode at 5-ambient temperatures (35, 25, 0, -7 and -15) and the exhaust emission test results were discussed. The results show that the vehicle with DPF emits much low PM(and PM number) on all of the test mode. However, NOx of the other mode was emitted higher than regulation mode. Also. NOx was sharply increased according to decreasing Ambient Temperature.

• Journal of ILASS-Korea
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• v.21 no.4
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• pp.200-206
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• 2016

Recently, the certification procedure for exhaust emission regulation of LDV has tested with the NEDC mode in the laboratory. But the on-road exhaust emissions exceed the standard emission limits. Therefore, it is important to analyze the real-driving emissions (RDE) with a portable emissions measurement system (PEMS). In present study, the on-road emissions were measured with a PEMS and evaluated by moving averaging window (MAW) method. Also, it was compared with the $CO_2$ and $NO_x$ emissions for real-driving and test modes from euro-6 light-duty vehicles equipped with SCR and LNT systems. In results, on-road $NO_x$ emission has been 2.3-10.0 times higher than the standard $NO_x$ emission limit on NEDC mode. The reason was that the test modes did not reflect traffic and various real-driving patterns sufficiently.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.13-18
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• 2012

This research is about the exhaust gas and driving performance test which are for CNG-Diesel dual fuel engine. The CNG-Diesel dual fuel engine converted from 2500cc diesel has two steps of injection systems; small amount of diesel is injected to mixture CNG in cylinder to ignite before CNG is injected into each intake manifold to form mixture. The amounts of output power and emission in duel fuel consumption were measured by engine dynamometer and exhaust gas analyzer. Over 90% of diesel consumption reduction, similar driving performance to current diesel engine and reduced emission on $CO_2$ and PM, respectively, were indicated through the measurements. The two steps of system were applied to vehicle to investigate exhaust gas characteristics and driving performance via NEDC mode and real driving test. Additional oxidation catalyst was applied to reduce emission on the test vehicle and the NEDC mode test showed the reduction of Co, $CO_2$, Pm and THC.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.74-80
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• 2009

The objective of this paper was to investigate the slip rate and the slip frequency number of damper clutch of torque converter in 2.4L passenger vehicle with 5-speed A/T and analyze the effect of slip control and control strategy on driving characteristics and the fuel economy. The newly developed torque converter with the more durable wet friction material and the slip-controlled damper clutch system, the DCC system, was installed, which was easily compatible and amendable of the lock-up clutch of the base system. The vehicle has been tested on the fuel economy modes such as FTP-75, HWFET and NEDC (ECE15+EUDC) driving cycle at chassis dynamometer. The DCC mode (II), of which the control strategy had both the lock-up and the slip-controlled clutch, and the DCC mode (I) with full slip-controlled clutch were compared with the base system with only the lock-up clutch. As the research result, comparison to base system, the fuel consumption of the vehicle with the DCC control (II) was effectively improved by 6.6% and 7.7% on FTP-75 and NEDC mode.

• Journal of Energy Engineering
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• v.17 no.4
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• pp.227-232
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• 2008

Carbon dioxide is considered a major greenhouse gas that contributes to global wanning. $CO_2$ is a major component of the exhaust in the combustion of any hydrocarbon fuel. The regulation for $CO_2$ emission from vehicles has become much more stringent in recent years. These more stringent regulations require vehicle manufacturers to develop alternative fuels that reduce exhaust emissions. This paper evaluated the correlation of $CO_2$ emission and fuel economy in the Gasoline, Diesel, and LPG vehicles according to FTP-75 and NEDC(ECE15+EUDC) driving mode. From this study, we discovered that the decrease rate of $CO_2$ emission is higher for fuels of lower carbon concentration. When the relationship between $CO_2$ emission and fuel consumption rate according to used fuels is expressed as a function, one can find out that they have a high correlation. LPG vehicles produce less $CO_2$ emission than gasoline and diesel vehicles.