Abstract: A method and an apparatus for detecting engine misfire has advantages of precisely detecting misfire occurrence when misfire continuously occurs at three or more engine cylinders and detecting an engine cylinder where the misfire occurs. The method may include calculating an angular acceleration factor value on the basis of an engine speed, calculating a variation value of an angular acceleration factor on the basis of the angular acceleration factor value, calculating a threshold point of misfire starting and a threshold point of misfire ending, comparing the variation value of the angular acceleration factor with the threshold point of misfire starting, comparing the variation value of the angular acceleration factor with the threshold point of misfire ending, and detecting a cylinder of the engine where the misfire occurs by the comparison results.

Abstract: The polymeric carrier for delivering nucleic acid material to a cell is provided herein. The polymeric carrier can include a dendrimer group having 2 to 8 termini, each of the termini having an arginine-grafted bioreducible polymer attached thereto. In one embodiment, only a portion of the termini can have an arginine-grafted bioreducible polymer attached thereto.

Abstract: An exhaust gas condensate control method includes selecting modeling objects from the exhaust gas recirculation (EGR) system, acquiring control factors from the modeling objects, such as mass, temperature, pressure, absolute humidity, relative humidity, partial water vapor pressure of the exhaust gas and a gas mixture, calculating an estimated relative humidity value, a desired relative humidity value from estimated relative humidity value, and an allowable relative humidity limit and a current relative humidity value of the EGR system, and precluding production of condensate in the EGR system by feedback-controlling the intake air flow rate of a mixing pipe line, the opening amount of an LP-EGR (low pressure) valve, and boost pressure by using an applied control value compensating the desired relative humidity value. An EGR system may be an LP-EGR type or an HP-EGR (high pressure)+LP-EGR type.

Abstract: A control method for a low pressure exhaust gas recirculation (LP-EGR) system may include measuring an engine speed and load, setting a target pressure difference between a downstream side and an upstream side of a LP-EGR valve according to the measured engine speed and load, measuring a present pressure difference between the downstream and upstream sides of the LP-EGR valve, comparing the present pressure difference with the target pressure difference, and preventing a reverse flow of a recirculated exhaust gas by adjusting an opening rate of the LP-EGR valve to alter a recirculated exhaust gas amount when the present pressure difference is smaller than the target pressure difference. The LP-EGR system for preventing reverse flow of a recirculated exhaust gas may include an air intake line, an exhaust line, a LP-EGR line, a LP-EGR valve, pressure sensors and a control portion.

Abstract: A method of predicting NOx generation amount may include calculating NO generation rate by using a combustion pressure of an engine and driving variables of the engine, obtaining NO generation period by using the combustion pressure of the engine, calculating NO generation amount based on the NO generation rate and the NO generation period, and predicting the NOx generation amount by obtaining NO2 generation amount based on a ratio between NO and NO2 according to the NO generation amount and a driving condition of the engine.

Abstract: A low pressure exhaust gas recirculation (EGR) cooler efficiency diagnosis method for an EGR system includes measuring speed and load of an engine, setting a difference threshold between model temperature and detected temperature downstream of the low pressure EGR cooler according to speed and load of the engine, measuring a pressure difference between upstream and downstream sides of the EGR valve, calculating a mass flow rate of an exhaust gas passing through the low pressure EGR cooler based on the measured pressure difference, calculating the efficiency of the low pressure EGR cooler based on the calculated mass flow rate, calculating the model temperature downstream of the low pressure EGR cooler based on the calculated efficiency, and comparing the model temperature downstream of the low pressure EGR cooler with the detected temperature downstream of the low pressure EGR cooler. A low pressure EGR system is also disclosed.

Abstract: An EGR system control method of an engine may include calculating a target mass flux ({dot over (m)}egrd) of EGR gas flowing an EGR line, calculating an effective flowing area (EFA) of an EGR valve disposed on the EGR line, calculating an EGR flow sensitivity by dividing the target mass flux with the effective flowing area, and controlling a real opening rate of the EGR valve by applying the EGR flow sensitivity to a target opening rate of the EGR valve. Accordingly, a gain value is varied on a real time according to an effective flowing area of the EGR valve and a target mass flux of EGR gas such that real opening rate of an EGR valve is accurately and precisely controlled.

Abstract: A method and a system for monitoring exhaust gas recirculation are provided that measures a state of an engine, judges an applied system between a high-pressure EGR system and a low-pressure EGR system according to the measured state of the engine, and judges whether a system is erroneous by measuring the position of an EGR valve of an unapplied EGR system and comparing the position with a predetermined reference position.

Abstract: A method and a system for monitoring exhaust gas recirculation are provided that measures a state of an engine, judges an applied system between a high-pressure EGR system and a low-pressure EGR system according to the measured state of the engine, and judges whether a system is erroneous by measuring the position of an EGR valve of an unapplied EGR system and comparing the position with a predetermined reference position.

Abstract: A method of predicting NOx generation amount may include calculating NO generation rate by using a combustion pressure of an engine and driving variables of the engine, obtaining NO generation period by using the combustion pressure of the engine, calculating NO generation amount based on the NO generation rate and the NO generation period, and predicting the NOx generation amount by obtaining NO2 generation amount based on a ratio between NO and NO2 according to the NO generation amount and a driving condition of the engine.

Abstract: A system and a method for controlling NOx may include predicting NOx generation amount by using a virtual sensor; comparing the NOx prediction amount with a predetermined NOx target amount; and controlling the NOx generation amount so as for the NOx prediction amount to follow the NOx target amount.

Abstract: A system and method for judging an abnormal condition of a combustion pressure sensor, may include determining whether a driving condition of a vehicle, a fuel injection condition, and an intake air condition may be satisfied, deriving a relational equation from an amount of air measured in real time and a combustion pressure measured by the combustion pressure sensor, and monitoring a slope and a y-intercept of the relational equation when the driving condition, the fuel injection condition, and the intake air condition may be satisfied, determining whether the slope and the y-intercept may be in a predetermined normal range, accumulating the number of times the slope and the y-intercept may be beyond the predetermined normal range, and outputting a warning when the accumulated number reaches a number which may be predetermined as an abnormal condition number of the sensor.

Abstract: A low pressure exhaust gas recirculation (EGR) cooler efficiency diagnosis method for an EGR system includes measuring speed and load of an engine, setting a difference threshold between model temperature and detected temperature downstream of the low pressure EGR cooler according to speed and load of the engine, measuring a pressure difference between upstream and downstream sides of the EGR valve, calculating a mass flow rate of an exhaust gas passing through the low pressure EGR cooler based on the measured pressure difference, calculating the efficiency of the low pressure EGR cooler based on the calculated mass flow rate, calculating the model temperature downstream of the low pressure EGR cooler based on the calculated efficiency, and comparing the model temperature downstream of the low pressure EGR cooler with the detected temperature downstream of the low pressure EGR cooler. A low pressure EGR system is also disclosed.

Abstract: A control method for a low pressure exhaust gas recirculation (LP-EGR) system may include measuring an engine speed and load, setting a target pressure difference between a downstream side and an upstream side of a LP-EGR valve according to the measured engine speed and load, measuring a present pressure difference between the downstream and upstream sides of the LP-EGR valve, comparing the present pressure difference with the target pressure difference, and preventing a reverse flow of a recirculated exhaust gas by adjusting an opening rate of the LP-EGR valve to alter a recirculated exhaust gas amount when the present pressure difference is smaller than the target pressure difference. The LP-EGR system for preventing reverse flow of a recirculated exhaust gas may include an air intake line, an exhaust line, a LP-EGR line, a LP-EGR valve, pressure sensors and a control portion.

Abstract: An exhaust gas condensate control method includes selecting modeling objects from the exhaust gas recirculation (EGR) system, acquiring control factors from the modeling objects, such as mass, temperature, pressure, absolute humidity, relative humidity, partial water vapor pressure of the exhaust gas and a gas mixture, calculating an estimated relative humidity value, a desired relative humidity value from estimated relative humidity value, and an allowable relative humidity limit and a current relative humidity value of the EGR system, and precluding production of condensate in the EGR system by feedback-controlling the intake air flow rate of a mixing pipe line, the opening amount of an LP-EGR (low pressure) valve, and boost pressure by using an applied control value compensating the desired relative humidity value. An EGR system may be an LP-EGR type or an HP-EGR (high pressure)+LP-EGR type.

Abstract: An EGR system control method of an engine may include calculating a target mass flux ({dot over (m)}egrd) of EGR gas flowing an EGR line, calculating an effective flowing area (EFA) of an EGR valve disposed on the EGR line, calculating an EGR flow sensitivity by dividing the target mass flux with the effective flowing area, and controlling a real opening rate of the EGR valve by applying the EGR flow sensitivity to a target opening rate of the EGR valve. Accordingly, a gain value is varied on a real time according to an effective flowing area of the EGR valve and a target mass flux of EGR gas such that real opening rate of an EGR valve is accurately and precisely controlled.

Abstract: A turbocharger protecting method of an engine provided with an LP-EGR including an engine, a turbocharger disposed downstream of the engine, an exhaust gas post processing device disposed downstream of the turbocharger, an LP-EGR (low pressure exhaust gas recirculation) valve disposed downstream of the exhaust gas post processing device, an LP-EGR cooler disposed downstream of the LP-EGR valve, and an air supply line connecting downstream of the LP-EGR cooler and a compressor of the turbocharger, the turbocharger protecting method includes predetermining compressor inlet limiting temperature, estimating compressor inlet temperature and comparing the estimated compressor inlet temperature and the predetermined compressor inlet limiting temperature, and lowering the compressor inlet temperature if the estimated compressor inlet temperature excesses the predetermined compressor inlet limiting temperature.

Abstract: An exhaust gas control method of an engine may include calculating a target mass flux of EGR gas by using air mass entering into a cylinder and target air mass supplied into the engine, calculating a target effective flow area (EFAd) of the EGR valve by using a target mass flux of the EGR gas and front/rear condition of the EGR valve, and calculating a valve opening rate of the EGR valve by using a predetermined curve fitting formula and the target effective flow area (EFAd). Accordingly, a target mass flux of EGR gas flowing an EGR line is calculated to be applied an opening rate of the EGR valve thereby such that a flux of the EGR gas precisely and quickly is control.

Abstract: A low pressure EGR valve is controlled by mixing EGR gas into an intake air. Steps of the method include detecting temperature and pressure of an intake air passing through an air cleaner, detecting temperature and pressure of the intake air at a downstream side of an intercooler, detecting temperature and pressure of an EGR gas at an upstream side of an EGR cooler, determining a control duty of the low pressure EGR valve on the basis of the detected temperature and pressure of the air passing through the air cleaner, the detected temperature and pressure at the downstream side of the intercooler, and the detected temperature and pressure at the upstream side of the EGR cooler, and controlling the low pressure EGR valve based on the determined control duty. An apparatus for executing the method is also provided.

Abstract: A low pressure EGR valve is controlled by mixing EGR gas into an intake air. Steps of the method include detecting temperature and pressure of an intake air passing through an air cleaner, detecting temperature and pressure of the intake air at a downstream side of an intercooler, detecting temperature and pressure of an EGR gas at an upstream side of an EGR cooler, determining a control duty of the low pressure EGR valve on the basis of the detected temperature and pressure of the air passing through the air cleaner, the detected temperature and pressure at the downstream side of the intercooler, and the detected temperature and pressure at the upstream side of the EGR cooler, and controlling the low pressure EGR valve based on the determined control duty. An apparatus for executing the method is also provided.