Device and method for controlling exhaust gas recirculation

Abstract

An exhaust gas recirculation control device (100) comprising: an EGR valve (10) configured to adjust a flow rate of an EGR gas recirculated from an exhaust manifold (80) to an intake manifold (20), an intake manifold absolute pressure sensor (MAP sensor) (30) which is configured to measure a pressure within the intake manifold (20), a throttle valve (60) which is arranged to control an amount of incoming air, an ignition device (110) attached to an internal combustion engine, an injector (120) which is arranged to inject a fuel, an accelerator pedal position sensor (140) configured to measure an accelerator pedal angle, a crankshaft position sensor (130) which is arranged to measure the revolutions per minute of the internal combustion engine, a vehicle speed sensor (150) configured to measure a speed of a vehicle, and a control section (70) configured to receive a signal of the pressure within the intake manifold (20) from the MAP sensor (30), calculate a ratio of the EGR gas for a total volume of the intake manifold using a pressure change within the intake manifold (20), calculate a pressure of the EGR gas by multiplying the pressure of the intake manifold (20) and the ratio of the EGR gas, and convert the pressure of the EGR gas into a flow rate of the EGR gas, wherein the ratio of the EGR gas to the total volume of the intake manifold (20) is calculated based on an assumption that the pressure change within the intake manifold (20) is generated according to a change in the opening of an EGR valve (10) which is configured to adjust the flow rate of the EGR gas returned from an exhaust manifold (80) to the intake manifold (20).

Description

Field of the invention

[0001] The present invention relates to an exhaust gas recirculation control device and an exhaust gas recirculation control method, and more particularly to an exhaust gas recirculation control device and an exhaust gas recirculation control method which use an intake manifold absolute pressure sensor (MAP sensor, derived from the English term “manifold absolute pressure sensor”). Description of the technology used

[0002] The exhaust gas of an internal combustion engine contains large amounts of toxic components such as CO, HC, and NOx (nitrogen oxides). In particular, the amount of nitrogen oxides produced increases as the combustion temperature of the internal combustion engine rises, so it is necessary to reduce the combustion temperature of the internal combustion engine to reduce the nitrogen oxides in the exhaust gas.

[0003] Among the reasons for the increase in combustion temperature of the internal combustion engine, a major reason is that high-temperature heat is instantaneously generated corresponding to the increase in propagation speed of flames ignited at a spark plug in a state where an air-fuel ratio of the air-fuel mixture gas within a combustion chamber is in a rich state.

[0004] A method for lowering a combustion temperature of the internal combustion engine in order to reduce the amount of NOx contained in the exhaust gas includes an exhaust gas recirculation method (also EGR method) for lowering a combustion temperature of the internal combustion engine by reducing a density of the mixed gas without changing an inherent or predetermined air-fuel ratio by mixing a part of the exhaust gas with fresh air and admitting the mixed gas into a combustion chamber.

[0005] The exhaust gas recirculation (EGR) process is used to improve the fuel efficiency of a gasoline internal combustion engine and to reduce the amount of NOx contained in the exhaust gas. Using the exhaust gas recirculation (EGR) process, it is possible to simultaneously reduce the amount of NOx and advance (or retard) the ignition timing, thereby preventing knocking or the knocking generation region. Consequently, it is possible to improve the engine's output and fuel efficiency.

[0006] To accurately control the recirculation of exhaust gas, the amount of EGR gas recirculated to the intake manifold must be accurately measured. One method for measuring the amount of EGR gas includes a method for measuring a flow rate of the EGR gas by installing a flow rate sensor in an EGR pipe.

[0007] If, as described above, a separate sensor is installed to measure the amount of EGR gas returned to the intake manifold, then a structure of the internal combustion engine becomes complex and production costs increase due to the use of additional components.

[0008] The above information disclosed in the section "Background of the Invention" is provided merely to facilitate understanding of the general background of the invention and should not be considered as an admission or any suggestion that this information belongs to the prior art as it is (already) known to those skilled in the art.

[0009] Furthermore, from DE 10 2011 009 114 A1 a method for estimating an oxygen concentration in an intake manifold of a diesel engine using exhaust gas recirculation is known, which comprises: monitoring engine operation, monitoring an exhaust gas recirculation valve and monitoring an air / fuel ratio of exhaust gas, wherein, when the engine is operating in steady state with the exhaust gas recirculation valve in the closed position, a volumetric efficiency for the engine is updated, a partial pressure due to exhaust gas recirculation in the intake manifold is determined based on the updated volumetric efficiency, and an estimated oxygen concentration in the intake manifold is determined based on the partial pressure due to exhaust gas recirculation in the intake manifold and the air / fuel ratio of the exhaust gas,wherein the operation of the engine is controlled based on the estimated oxygen concentration in the intake manifold. Further exhaust gas recirculation devices and methods, as well as related techniques, are known from EP 2 128 407 A1 and EP 1 148 228 A2. Explanation of the invention

[0010] It is an object of the present invention to provide an exhaust gas recirculation control device and an exhaust gas recirculation control method which have the advantages of calculating the amount of EGR gas recirculated to an intake manifold and controlling according to the calculated amount of EGR gas, while minimizing the number of mounted sensors.

[0011] To this end, the present invention provides an exhaust gas recirculation control device according to claim 1 and an exhaust gas recirculation control method according to claim 7. Advantageous further developments are described in the dependent claims.

[0012] Thus, the present invention provides an exhaust gas recirculation control device comprising: an EGR valve (or exhaust gas recirculation valve) configured to adjust or adapt a flow rate (or mass flow rate, or volume flow) of the EGR gas (or recirculated exhaust gas) recirculated from an exhaust manifold to (or into) an intake manifold, an intake manifold absolute pressure sensor (MAP sensor, derived from the English term "manifold absolute pressure sensor") configured to measure a pressure within the intake manifold, a throttle valve configured to control an amount of incoming air (e.g. intake air), an ignition device mounted or configured (in short: mounted) on or for an internal combustion engine, an injector (e.g.an injection valve) configured to inject fuel, an accelerator pedal position sensor configured to measure an accelerator pedal angle, a crankshaft position sensor configured to measure the revolutions per minute of the internal combustion engine (or the rotational speed of the internal combustion engine), a vehicle speed sensor configured to measure a speed of a vehicle (e.g., a motor vehicle, e.g., an automobile), and a control section (or control device) configured to receive a signal of the pressure within the intake manifold from the MAP sensor, a ratio of the EGR gas for (or with respect to) a total volume(s) of the intake manifold using a pressure change (e.g.,a pressure fluctuation) within the intake manifold, calculate an EGR gas pressure by multiplying the intake manifold pressure and the EGR gas ratio, and convert the EGR gas pressure into an EGR gas flow rate.

[0013] The control section can compensate (or correct or adjust) an ignition timing of the internal combustion engine by means of the flow rate of the EGR gas by (e.g., temporally) advancing / earlier controlling the ignition device (e.g., by advancing the ignition timing).

[0014] The control section may calculate a flow rate of the EGR gas by applying the pressure of the EGR gas to a flow rate function (or mass flow rate function) corresponding to an open area (or open region) of the EGR valve.

[0015] The control section may calculate the intake air pressure by subtracting the calculated EGR gas pressure from the pressure inside the intake manifold and may convert the intake air pressure into an intake air flow rate.

[0016] The control section may calculate the flow rate of intake air flowing into the intake manifold using the temperature of the intake air, the volume of the intake manifold, and the pressure of the intake air.

[0017] The control section may control an operation of an injector by calculating the amount of fuel which is set (or determined) according to the flow rate of the intake air.

[0018] An exhaust gas recirculation control method according to the invention comprises: measuring the pressure within an intake manifold using a MAP sensor, calculating the pressure of the EGR gas by multiplying the pressure within the intake manifold by a ratio of the EGR gas for a total volume of the intake manifold, and converting the pressure of the EGR gas into a flow rate of the EGR gas.

[0019] Converting the pressure of the EGR gas into a flow rate of the EGR gas may include: calculating the flow rate of the EGR gas by applying the pressure of the EGR gas to a flow rate function (e.g., a mass flow rate function) corresponding to an open area (or open region) of an EGR valve configured to adjust the flow rate of the EGR gas recirculated from an exhaust manifold to the intake manifold.

[0020] The method may further comprise compensating (correcting) an ignition timing of the internal combustion engine according to the flow rate of the EGR gas calculated using the pressure of the EGR gas.

[0021] The method may further comprise calculating the pressure of the intake air supplied to the intake manifold by subtracting the calculated pressure of the EGR gas from a value of the pressure of the intake manifold, and converting the pressure of the intake air into a flow rate of the intake air.

[0022] Converting the intake air pressure into the intake air flow rate can be realized using the intake air temperature, the intake manifold volume, and the intake air pressure.

[0023] The method may further comprise: supplying fuel by calculating the amount of fuel which is set (or determined) according to the flow rate of the intake air which is calculated by means of the pressure of the intake air.

[0024] The ratio of EGR gas to the total volume of the intake manifold can be calculated using the pressure change (e.g. pressure fluctuation) within the intake manifold.

[0025] The ratio of the EGR gas for (or with respect to) the total volume of the intake manifold is calculated according to the invention based on an assumption that the pressure change within the intake manifold is generated according to a change in the opening of an EGR valve (e.g., the opening angle or position of an EGR valve) which is configured to adjust or adjust the flow rate of the EGR gas recirculated from an exhaust manifold to the intake manifold.

[0026] According to various aspects of the present invention, it is possible to calculate the amount of EGR gas returned to the intake manifold using the intake manifold absolute pressure sensor / manifold absolute pressure sensor (MAP sensor) mounted in the intake manifold, and it is not necessary to install a mass air flow sensor (MAF sensor) and the like for measuring the amount of EGR gas.

[0027] Since it is not necessary to separately install the MAF sensor and the like for measuring the amount of EGR gas, it is possible to simplify a structure of the internal combustion engine and reduce production costs.

[0028] The methods and apparatus of the present invention have other features and advantages which will be apparent from, or set forth in more detail in, the accompanying drawings incorporated herein and the following detailed description, which together serve to explain certain principles of the present invention. Short description of the drawings Fig. 1 is a block diagram illustrating an exemplary exhaust gas recirculation control device according to the present invention. Fig. 2 is a flowchart illustrating an exemplary exhaust gas recirculation control method according to the present invention. Detailed description

[0029] Reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in connection with the exemplary embodiments, it is to be understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, changes, modifications, and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0030] Throughout the description, the same reference symbols identify the same (or similar) elements / components.

[0031] When this specification and the following claims describe an element as being "connected" to another element, the element may be "directly connected" to the other element or "electrically connected" to the other element by means of a third element. Furthermore, unless explicitly stated otherwise, the word "comprise" or "include" and various variations, such as "comprises" or "having," are intended to mean / imply the inclusion of the recited elements, but not the exclusion of any other elements.

[0032] Fig. 1 is a block diagram illustrating an exemplary exhaust gas recirculation control device according to various embodiments of the present invention.

[0033] Referring to Fig. 1 comprises an exhaust gas recirculation control device 100: an exhaust gas recirculation valve (EGR valve for short) 10, an intake manifold absolute pressure sensor / manifold absolute pressure sensor (MAP sensor) 30, a throttle valve 60 for controlling the amount of incoming air (e.g., intake air), an ignition device 110 for controlling combustion in an internal combustion engine, an injector (e.g., an injection valve) 120 for injecting fuel, an accelerator pedal position sensor 130 for measuring an accelerator pedal angle, a crankshaft position sensor 140 for measuring the revolutions per minute of the internal combustion engine (or the rotational speed of the internal combustion engine), a vehicle speed sensor 150 for measuring a speed of the vehicle, and a control section (or control device) 70.

[0034] The control section 70 may be an engine control unit (ECU) for controlling a general operation of an internal combustion engine.

[0035] The EGR valve 10 is installed on an EGR pipe 11 connecting an exhaust manifold 80 and an intake manifold 20. The EGR valve 10 adjusts an EGR gas flow recirculated from the exhaust manifold 80 to the intake manifold 20 according to the control of the control section 70. The EGR valve 10 can be actuated by a solenoid method or a DC motor method.

[0036] The MAP sensor 30 is installed in the intake manifold 20 to measure the pressure P im within the intake manifold 20 and to transmit or transmit an associated signal to the control section 70.

[0037] The intake manifold 20 uniformly supplies air, which flows in through an air filter 40, to a combustion chamber of the internal combustion engine.

[0038] The throttle valve 60 is installed upstream of the intake manifold 20. The throttle valve 60 sets or adjusts a flow rate (or a mass flow rate, or a volume flow) ṁ thr the intake air supplied to the intake manifold 20 according to the control of the control section 70.

[0039] The control section 70 can provide a pressure value P im of the intake manifold 20 from the MAP sensor 30, and can determine a flow rate (or a mass flow rate, or a volume flow) ṁ agr of the EGR exhaust gas using the obtained pressure value P im calculate.

[0040] Further, the control section 70 controls an operation of the ignition device 110 by compensating (correcting) an ignition timing according to the set flow rate ṁ agr of the EGR exhaust gas.

[0041] In addition, the control section 70 can set a flow rate ṁ thrthe intake air supplied to the intake manifold 20 using the pressure P im within the intake manifold 20. Further, the control section 70 injects by controlling an operation of the injector 120 according to the set flow rate ṁ thr the intake air, a load of the combustion engine and a speed a predetermined flow rate (or a mass flow rate, or a volume flow) of fuel ṁ cps into the intake manifold 20. In an internal combustion engine with gasoline direct injection (GDI engine), the fuel can be injected directly into the combustion chamber 90.

[0042] The accelerator pedal position sensor 130 measures a position of an accelerator pedal depressed by a driver and provides a corresponding signal to the control section 70.

[0043] The crankshaft position sensor 130 measures the revolutions per minute (or speed) of a crankshaft and supplies or transmits a corresponding signal, ie, a speed signal, to the control section 70.

[0044] The vehicle speed sensor 150 measures a speed of the vehicle and supplies or transmits a corresponding signal to the control section 70.

[0045] The exhaust gas recirculation control device according to various embodiments of the present invention may further include an EGR cooler 50 (e.g., a recirculated exhaust gas cooler) provided on the EGR pipe 11.

[0046] An exhaust gas recirculation control method using the exhaust gas recirculation control device 100 will be described below.

[0047] Fig. 2 is a flowchart illustrating an exemplary exhaust gas recirculation control method according to various embodiments of the present invention.

[0048] If, with reference to Fig. 2, the engine is started (S110), then the control section 70 determines whether an EGR activation condition is satisfied (S120). If the EGR activation condition satisfies a case or condition in which a vehicle speed is equal to or higher than a predetermined speed, e.g., 20 km / h, in which the revolutions per minute (rpm) of the engine (or the rotational speed of the engine) is equal to or higher than a predetermined value of the revolutions per minute (or a predetermined rotational speed), e.g., 800 rpm, and in which a flow rate ṁ cpsof the fuel injected according to the amount of intake air is equal to or greater than a reference value, then the control section 70 can determine that the EGR activation condition is satisfied.

[0049] If the EGR activation condition is not satisfied, then the control section 70 closes the EGR valve 10 by controlling an operation of the EGR valve 10 (S125).

[0050] If the EGR activation condition is met, the control section 70 sets an EGR target point (S130). The EGR target point represents a target flow rate (or a target mass flow rate, or a target volume flow rate) of the EGR gas to be recirculated from the exhaust manifold 40 to the intake manifold 20. In this case, the control section 70 opens the EGR valve 10 to allow the EGR gas to flow into the intake manifold 20.

[0051] The target flow rate of the EGR gas can be determined by means of a predetermined map according to the accelerator pedal position sensor 130, the crankshaft position sensor 140, the vehicle speed sensor 150, the flow rate ṁ cps of the fuel and the like.

[0052] According to the inflow of the EGR gas and the intake air into the intake manifold 20, the pressure P im inside the intake manifold 20. The pressure P im within the intake manifold 20 is a sum of the pressure of the EGR gas and the pressure corresponding to the intake air. The pressure P im within the intake manifold 20 is measured by means of the MAP sensor 30.

[0053] The control section 70 calculates a ratio of the EGR gas in a total volume of the intake manifold 20 (S140).

[0054] The control section 70 calculates the pressure of the EGR gas by multiplying the pressure P imwithin the intake manifold 20, which is measured by the MAP sensor, with the ratio of the EGR gas (S150).

[0055] The control section 70 calculates the flow rate ṁ agr of the EGR gas using the pressure of the EGR gas (S155).

[0056] The control section 70 calculates a temperature T im of the intake manifold 20, for example, using the pressure of the EGR gas and a predetermined total volume V im of the intake manifold 20 using an equation for an ideal gas.

[0057] The flow rate ṁ thr of the intake air can be calculated using the total volume V im of the intake manifold 20, the temperature T imwithin the intake manifold 20 and the pressure of the intake air from the pressure within the intake manifold 20. Furthermore, a temperature of the EGR gas and the fresh gas (e.g., fresh air) can be measured by including a separate temperature sensor in the intake manifold 20.

[0058] The control section 70 may calculate a ratio of the EGR gas within the intake manifold 20 using a flow rate function according to an open area of ​​the EGR valve 10.

[0059] Equation 1 represents a flow rate function according to an open area (or an open region) of the EGR valve 10. m˙=A×P×C×Ψ (St. Venant's equation)

[0060] Here, m represents a flow rate (or mass flow rate) of a gas, A represents an open area of ​​the valve (e.g., the area of ​​an open region of the valve), P represents a pressure of the gas, C represents a temperature constant, and Ψ is a pressure ratio.

[0061] Equation 1 can be used as a flow rate function corresponding to an open area (or an open region) of the EGR valve 10. In this case, the open area of ​​the EGR valve 10 is a value determined according to the control of the control section 70, and the temperature constant C can be determined (e.g., determined) by a predetermined map.

[0062] A volume of the exhaust manifold 80 has a predetermined value, and the pressure and temperature of the exhaust manifold 80 can be determined by a map determined by an experiment according to an operating state of the internal combustion engine, that is, according to a rotational speed, a vehicle speed and the fuel flow rate ṁ cps , be determined (e.g. fixed or determined).

[0063] Furthermore, the pressure ratio Ψ of the exhaust gas of the EGR gas discharged from the exhaust manifold 80 and flowing through the EGR valve 10 may be determined (e.g., fixed or determined) by a map predetermined by an experiment.

[0064] Further, even if the EGR cooler 50 provided in the EGR pipe 11 is provided, the pressure ratio Ψ of the exhaust gas can be determined by a map given by an experiment.

[0065] Consequently, it is possible to calculate a flow rate of the EGR gas by applying the pressure of the EGR gas to the flow rate function of Equation 1.

[0066] When the control section 70 controls the opening of the EGR valve 10 by setting the EGR target point (S130), the pressure within the intake manifold 20 is changed, and the changed pressure is calculated as a pressure change of the EGR gas to determine a ratio of the EGR gas within the intake manifold 20. The ratio of the EGR gas within the intake manifold 20 can be determined by converting a pressure change due to the opening of the EGR valve into the ratio of the EGR gas in the gas within the intake manifold 20 according to the map predetermined by the experiment.

[0067] The control section 70 calculates the pressure of the EGR gas by multiplying the pressure P imwithin the intake manifold 20, which is measured by the MAP sensor 30, with the ratio of the EGR gas (S150).

[0068] Furthermore, a flow rate ṁ agr of the EGR gas can be calculated by inserting the calculated pressure of the EGR gas into Equation 1 (S155).

[0069] The control section 70 compensates for an ignition timing of the internal combustion engine by controlling an operation of the ignition device 110 (e.g., early ignition of the gas mixture) in accordance with the flow rate ṁ agr of the EGR gas (S160).

[0070] The control section 70 calculates the intake air pressure by subtracting the EGR gas pressure from the intake manifold pressure 20 measured by the MAP sensor 30 (S170).

[0071] The control section 70 calculates a temperature T imof the intake manifold 20 using the pressure of the EGR gas and the determined (or specified) total volume V im of the intake manifold 20, for example, using an equation for an ideal gas.

[0072] The control section 70 can set a flow rate ṁ thr of the intake air using the pressure and temperature T im Calculate the intake air (S175).

[0073] If the MAP sensor 30 is a sensor capable of measuring a temperature, then the MAP sensor 30 can measure the flow rate ṁ thr of the intake air by measuring the temperature T im of the intake manifold 20 (S175).

[0074] The control section 70 can control the flow rate ṁ thr of the intake air flowing into the intake manifold 20 for a unit time using the temperature of the intake air, the volume of the intake manifold 20 and the pressure of the intake air.

[0075] The control section 70 controls the operation of the injector 120 by determining the amount of fuel which is supplied according to the flow rate ṁ thr the intake air is fixed (or determined) (S180).

[0076] The control section 70 determines whether the engine is turned off (S190).

[0077] If the engine is not turned off, the control section 70 controls the exhaust gas recirculation device adaptively to a change in the operating condition of the vehicle by repeatedly performing step S120 of determining whether the EGR activation condition is satisfied until step S180 of injecting the fuel.

[0078] According to various embodiments of the present invention, it is possible to reduce the number of sensors for controlling a flow rate of EGR gas and an ignition timing and the amount of injected fuel, thereby reducing the cost of the vehicle.

[0079] The foregoing description of certain exemplary embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many changes and modifications are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical applicability to thereby enable those skilled in the art to make and use various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the appended claims.

Claims

[1] An exhaust gas recirculation control device (100) comprising: an EGR valve (10) configured to adjust a flow rate of an EGR gas recirculated from an exhaust manifold (80) to an intake manifold (20), an intake manifold absolute pressure sensor (MAP sensor) (30) which is configured to measure a pressure within the intake manifold (20), a throttle valve (60) which is arranged to control an amount of incoming air, an ignition device (110) attached to an internal combustion engine, an injector (120) which is arranged to inject a fuel, an accelerator pedal position sensor (140) configured to measure an accelerator pedal angle, a crankshaft position sensor (130) which is arranged to measure the revolutions per minute of the internal combustion engine, a vehicle speed sensor (150) configured to measure a speed of a vehicle, and a control section (70) configured to receive a signal of the pressure within the intake manifold (20) from the MAP sensor (30), calculate a ratio of the EGR gas for a total volume of the intake manifold using a pressure change within the intake manifold (20), calculate a pressure of the EGR gas by multiplying the pressure of the intake manifold (20) and the ratio of the EGR gas, and convert the pressure of the EGR gas into a flow rate of the EGR gas, wherein the ratio of the EGR gas to the total volume of the intake manifold (20) is calculated based on an assumption that the pressure change within the intake manifold (20) is generated according to a change in the opening of an EGR valve (10) which is configured to adjust the flow rate of the EGR gas returned from an exhaust manifold (80) to the intake manifold (20). [2] The apparatus according to claim 1, wherein the control section (70) compensates an ignition timing of the internal combustion engine by the flow rate of the EGR gas by forwardly controlling the ignition device. [3] The device according to claim 1, wherein the control section (70) calculates a flow rate of the EGR gas by applying the pressure of the EGR gas to a flow rate function corresponding to an opened area of ​​the EGR valve (10). [4] The apparatus according to claim 1, wherein the control section (70) calculates the pressure of the intake air by subtracting the calculated pressure of the EGR gas from the pressure inside the intake manifold (20) and converts the pressure of the intake air into a flow rate of the intake air. [5] The apparatus according to claim 4, wherein the control section (70) calculates the flow rate of the intake air flowing into the intake manifold (10) using the temperature of the intake air, the volume of the intake manifold and the pressure of the intake air. [6] The apparatus according to claim 4, wherein the control section (70) controls an operation of an injector (120) by calculating the amount of fuel set according to the flow rate of the intake air. [7] An exhaust gas recirculation control method comprising: Measuring the pressure within an intake manifold (20) using a MAP sensor (30), Calculating the pressure of the EGR gas by multiplying the pressure within the intake manifold (20) by a ratio of the EGR gas for a total volume of the intake manifold (20) (S150), and Converting the EGR gas pressure into an EGR gas flow rate (S155), wherein the ratio of the EGR gas to the total volume of the intake manifold (20) is calculated based on an assumption that the pressure change within the intake manifold (20) is generated according to a change in the opening of an EGR valve (10) which is configured to adjust the flow rate of the EGR gas returned from an exhaust manifold (80) to the intake manifold (20). [8] The method according to claim 7, wherein converting the pressure of the EGR gas into a flow rate of the EGR gas comprises: Calculating the flow rate of the EGR gas by applying the pressure of the EGR gas to a flow rate function corresponding to an open area of ​​an EGR valve (10) configured to adjust the flow rate of the EGR gas recirculated from an exhaust manifold (80) to the intake manifold (20). [9] The method according to claim 7, further comprising: Compensating an ignition timing of the internal combustion engine according to the flow rate of the EGR gas, which is calculated using the pressure of the EGR gas. [10] The method according to claim 7, further comprising: Calculating the pressure of the intake air supplied to the intake manifold (20) by subtracting the calculated pressure of the EGR gas from a value of the pressure of the intake manifold (20), and Converting intake air pressure into intake air flow rate. [11] The method according to claim 10, wherein converting the intake air pressure into the intake air flow rate is realized using the intake air temperature, the volume of the intake manifold (20) and the intake air pressure. [12] The method of claim 10, further comprising: Supplying fuel by calculating the amount of fuel which is determined according to the flow rate of intake air which is calculated by means of the pressure of the intake air. [13] The method according to claim 7, wherein the ratio of the EGR gas to the total volume of the intake manifold (20) is calculated using the pressure change within the intake manifold (20).

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