Control device for internal combustion engine

Abstract

The present disclosure provides a control device for an internal combustion engine that can estimate the amount of gas flowing into the cylinder of the internal combustion engine with higher accuracy than before. The control device (110) for the internal combustion engine has a mass flux calculation unit (F2), an opening area calculation unit (F3), an effective opening area calculation unit (F4), and a passing gas flow calculation unit (F5). The mass flux calculation unit (F2) calculates the mass flux (MF) of the gas passing through the throttle valve (125) based on the upstream side gas temperature (Tu), the upstream side gas pressure (Pu), and the downstream side gas pressure (Pd) of the throttle valve (125). The opening area calculation unit (F3) calculates the opening area (A) of the throttle valve (125) based on the opening (θ) of the throttle valve (125). The effective opening area calculation unit (F4) calculates the effective opening area (EA) of the throttle valve (125) based on the upstream side gas pressure (Pu), the downstream side gas pressure (Pd), the opening (θ), and the opening area (A). A gas flow rate (GF) passing through the throttle valve (125) is calculated based on the mass flux (MF) and the effective opening area (EA) by a gas flow rate calculation unit (F5).

Description

Technical Field

[0001] The present disclosure relates to a control device for an internal combustion engine. Background Art

[0002] An invention related to a control device for an internal combustion engine is known, which improves the calculation method of the amount of air filled in the cylinder of the internal combustion engine (hereinafter referred to as Patent Document 1). The control device for an internal combustion engine described in Patent Document 1 controls an internal combustion engine equipped with an electronic throttle system, which controls the throttle opening by driving a throttle valve through a throttle actuator. The control device for the internal combustion engine in the past is characterized by including an opening command value calculation unit, a delay unit, a throttle opening prediction unit, a cylinder filling air amount prediction unit, and a fuel injection amount calculation unit (same as claim 1).

[0003] The opening command value calculation unit calculates the opening command value based on the accelerator operation amount, etc. The delay unit delays the timing of outputting the opening command value calculated by the opening command value calculation unit to the throttle actuator. The throttle opening prediction unit predicts the subsequent throttle opening before delaying the output of the opening command value based on the opening command value before being delayed by the delay unit and the response delay characteristics of the electronic throttle system. The cylinder filling air amount prediction unit predicts the cylinder filling air amount based on the throttle opening predicted by the throttle opening prediction unit. The fuel injection amount calculation unit calculates the fuel injection amount based on the cylinder filling air amount predicted by the cylinder filling air amount prediction unit.

[0004] Furthermore, the cylinder filling air amount prediction unit predicts a change amount of the cylinder filling air amount until the intake valve closing timing based on the throttle opening predicted by the throttle opening prediction unit.

[0005] Then, the cylinder filling air amount prediction unit adds the predicted change amount to the base cylinder filling air amount calculated based on the current operating parameters to predict the cylinder filling air amount (same as claim 2).

[0006] In addition, the cylinder filling air amount prediction unit regards the throttle opening through which the intake air passes as a channel, and uses an intake system model that applies a mass conservation law to the throttle passing air amount and the intake air flowing in the throttle downflow passage. Furthermore, the cylinder filling air amount prediction unit predicts the change amount of the cylinder filling air amount until the intake valve closing timing by accumulating the change amount of the output of the intake system model until the intake valve closing timing (the same as claim 3).

[0007] The formula for calculating the throttle passing air amount in the intake system model is set as follows.

[0008] [Mathematical formula 1]

[0009]

[0010] A=πr 2 (1-cos 2 θ)

[0011] In the above formula, G_in is the amount of air passing through the throttle [kg / sec]. μ is the flow coefficient, and A is the effective cross-sectional area of ​​the throttle opening [m 2 ]. Pa is atmospheric pressure [Pa], Pm is intake pressure [Pa], R is gas constant, and T is intake temperature [K]. f(Pm / Pa) is a physical value determined by the ratio of intake pressure Pm to atmospheric pressure Pa. r is the radius of the throttle valve [m], and θ is the throttle opening. The cylinder filling air amount prediction unit calculates the throttled air amount. At this time, the cylinder filling air amount prediction unit calculates f(Pm / Pa) based on a table with Pm / Pa as a parameter, and calculates μ·A based on a table with the throttle opening as a parameter (same as claim 4).

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: Japanese Patent Application Publication No. 2002-201998 Summary of the invention

[0015] Technical problem to be solved by the invention

[0016] In the above-mentioned conventional internal combustion engine control device, when the air pressure on the upstream and downstream sides of the throttle valve changes rapidly, such as during transient operation of the internal combustion engine, the μ·A calculated based on the table may not be consistent with the actual μ·A. In this case, an error occurs in the calculation result of the throttle passing air amount, resulting in a decrease in the prediction accuracy of the cylinder filling air amount.

[0017] The present disclosure provides a control device for an internal combustion engine capable of estimating the amount of gas flowing into a cylinder of the internal combustion engine with higher accuracy than conventional devices.

[0018] Technical solutions adopted to solve technical problems

[0019] A control device for an internal combustion engine in one embodiment of the present invention comprises: a mass flux calculation unit, which calculates the mass flux of the gas passing through the throttle valve based on the upstream gas temperature, the upstream gas pressure and the downstream gas pressure of the throttle valve; an opening area calculation unit, which calculates the opening area of ​​the throttle valve based on the opening of the throttle valve; an effective opening area calculation unit, which calculates the effective opening area of ​​the throttle valve based on the upstream gas pressure, the downstream gas pressure, the opening and the opening area; and a gas flow calculation unit, which calculates the gas flow through the throttle valve based on the mass flux and the effective opening area.

[0020] Effects of the Invention

[0021] According to the above-described one aspect of the present disclosure, it is possible to provide a control device for an internal combustion engine capable of estimating the amount of gas flowing into a cylinder of the internal combustion engine with higher accuracy than conventional devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a system configuration diagram showing one embodiment of the control device for the internal combustion engine according to the present disclosure.

[0023] Figure 2 Yes means Figure 1 A block diagram of the schematic structure of a control device of an internal combustion engine.

[0024] Figure 3 yes Figure 2 Functional block diagram of a control device for an internal combustion engine.

[0025] Figure 4 Yes means Figure 3 A flowchart showing an example of a process flow performed by a control device for an internal combustion engine.

[0026] Figure 5 yes Figure 3 A more detailed functional block diagram of the effective opening area calculation unit is shown.

[0027] Figure 6 It is a graph showing the relationship between the pressure difference ΔP of the throttle valve and the correction coefficient μ.

[0028] Figure 7 It is a graph showing the relationship between the opening degree θ of the throttle valve and the correction coefficient μ.

[0029] Figure 8 is a schematic diagram of the airflow through the throttle valve.

[0030] Fig. 9 Yes Description Figure 3Graph showing the effect of a control device of an internal combustion engine.

[0031] Fig.10 Yes means Figure 3 A flowchart showing an example of a process flow performed by a control device for an internal combustion engine.

[0032] Fig.11 Yes Description Fig.10 A graph showing the effects of processing by a control device of an internal combustion engine is shown. DETAILED DESCRIPTION

[0033] Hereinafter, several embodiments of the control device for an internal combustion engine according to the present disclosure will be described with reference to the drawings.

[0034] [Implementation Method 1]

[0035] Figure 1 This is a system configuration diagram showing one embodiment of the control device for an internal combustion engine according to the present disclosure.

[0036] The control device 110 of the internal combustion engine according to the present embodiment controls, for example, Figure 1 An engine control unit (ECU) of an engine system 100 is shown. The engine system 100 includes, for example, a control device 110, an intake system 120, an engine 130, an exhaust system 140, and a supercharger 150.

[0037] Figure 2 It means composition Figure 1 The block diagram is a schematic structure of the control device 110 of the internal combustion engine of the engine system 100. The control device 110 of the internal combustion engine of the present embodiment includes, for example, a processing device 111 including a CPU, a storage device 112 including a RAM or a ROM, and a plurality of computer programs or data stored in the storage device 112. In addition, the control device 110 includes, for example, an input circuit 113 and an input / output port 114.

[0038] In addition, the control device 110 includes various circuits, such as a throttle drive circuit 115, an EGR valve drive circuit 116, a variable valve mechanism drive circuit 117, a fuel injection device drive circuit 118, an ignition output circuit 119, etc. In addition, the control device 110 may not have these drive circuits, and at least a part of these drive circuits can be provided outside the control device 110.

[0039] The intake system 120 includes, for example, an intake pipe 121, an atmospheric humidity sensor 122, a mass flow meter 123, an intercooler 124, a throttle valve 125, and an intake pipe pressure sensor 126. The intake pipe 121 introduces external air from the outside of the engine system 100 and supplies it to the engine 130. The atmospheric humidity sensor 122 is provided at the intake pipe 121 to measure the humidity of the air sucked into the intake pipe 121. The mass flow meter 123 is provided at the inlet of the intake pipe 121 to measure the mass flow rate of the air sucked into the intake pipe 121. In addition, the mass flow meter 123 has, for example, a built-in intake air temperature sensor 123a for measuring the intake air temperature.

[0040] The supercharger 150 includes a compressor 151 that compresses the inhaled air, and a turbine 152 that drives the compressor 151 using the energy of the exhaust gas. The intercooler 124 is disposed on the downstream side of the air flow in the intake pipe 121 closer to the supercharger 150, and cools the air compressed by the compressor 151 of the supercharger 150. The throttle valve 125 adjusts the amount of intake air sucked into the engine 130. For example, the throttle valve 125 has a built-in throttle position sensor 125a that measures the opening θ of the throttle valve 125. The intake pipe pressure sensor 126 is disposed on the downstream side of the air flow in the intake pipe 121 closer to the throttle valve 125, and measures the pressure of the air flowing through the intake pipe 121.

[0041] The engine 130 is, for example, a spark ignition type internal combustion engine. For example, the engine 130 includes a combustion chamber 131, a variable intake valve mechanism 132, a variable exhaust valve mechanism 133, a fuel injection device 134, a spark plug 135, a crank angle sensor 136, and an atmospheric pressure sensor 137. The variable intake valve mechanism 132 has a phase sensor 132a for detecting the switching phase of the intake valve, and controls the switching phase of the intake valve. The variable exhaust valve mechanism 133 has a phase sensor 133a for detecting the switching phase of the exhaust valve, and controls the switching phase of the exhaust valve. The fuel injection device 134 injects fuel into the combustion chamber 131. The spark plug 135 provides ignition energy to the mixture in the combustion chamber 131. The crank angle sensor 136 measures the crank angle, and the atmospheric pressure sensor 137 measures the atmospheric pressure.

[0042] The exhaust system 140 includes, for example, an exhaust pipe 141, a catalytic converter 142, an air-fuel ratio sensor 143, an EGR pipe 144, an EGR cooler 145, and an EGR valve 146. The exhaust pipe 141 discharges the exhaust gas of the engine 130 to the outside. The catalytic converter 142 is provided in the exhaust pipe 141 to purify the exhaust gas flowing through the exhaust pipe 141. The air-fuel ratio sensor 143 is provided in the exhaust pipe 141 on the upstream side closer to the exhaust flow than the catalytic converter 142 to measure the air-fuel ratio of the exhaust gas. For example, an oxygen concentration sensor may be used instead of the air-fuel ratio sensor 143.

[0043] The EGR pipe 144 is a pipe for performing exhaust gas recirculation (EGR), and for example, branches from the exhaust pipe 141 on the upstream side closer to the exhaust flow than the turbine 152 of the supercharger 150, and is connected to the intake pipe 121 on the downstream side closer to the intake air flow than the throttle valve 125. The EGR cooler 145 cools the exhaust gas that flows through the EGR pipe 144 and circulates to the intake pipe 121. The EGR valve 146 adjusts the flow rate of the exhaust gas that flows through the EGR pipe 144 and circulates to the intake pipe 121.

[0044] The control device 110 of the internal combustion engine of the present embodiment is connected to various sensors and actuators provided in the intake system 120, the engine 130, and the exhaust system 140 in a manner capable of information communication, for example, via a wireless or wired communication circuit or signal wiring. In addition, the control device 110 is also connected to an accelerator opening sensor 160 in a manner capable of information communication, and the accelerator opening sensor 160 measures the opening of the accelerator pedal of the vehicle equipped with the engine system 100, for example.

[0045] In more detail, the control device 110 is connected to, for example, an atmospheric humidity sensor 122, a mass flow meter 123, an intake air temperature sensor 123a, a throttle valve 125, a throttle position sensor 125a, and an intake pipe pressure sensor 126 in a manner capable of information communication. The atmospheric humidity sensor 122, the mass flow meter 123, the intake air temperature sensor 123a, the throttle position sensor 125a, and the intake pipe pressure sensor 126 respectively output signals S_iah, S_ifr, S_tmp, S_thr, and S_iap corresponding to the measured values. For example, the signals S_iah, S_ifr, S_tmp, S_thr, and S_iap output from the sensors of the intake system 120 are input to the input circuit 113 of the control device 110.

[0046] In addition, the control device 110 is connected to the variable intake valve mechanism 132, the variable exhaust valve mechanism 133, the phase sensors 132a, 133a, the fuel injection device 134, the spark plug 135, the crank angle sensor 136 and the atmospheric pressure sensor 137 in a manner capable of information communication, for example. The phase sensor 132a of the variable intake valve mechanism 132, the phase sensor 133a of the variable exhaust valve mechanism 133, the crank angle sensor 136 and the atmospheric pressure sensor 137 respectively output signals S_iph, S_eph, S_cra, S_oap corresponding to the measured values. For example, the signals S_iph, S_eph, S_cra, S_oap output from the sensors of the engine 130 are input to the input circuit 113 of the control device 110.

[0047] In addition, the control device 110 is connected to the air-fuel ratio sensor 143 and the EGR valve 146, for example, in a manner capable of information communication. The air-fuel ratio sensor 143 of the exhaust system 140 outputs a signal S_afr corresponding to the measured value. For example, the signal S_afr output from the air-fuel ratio sensor 143 is input to the input circuit 113 of the control device 110. In addition, the control device 110 is connected to the accelerator opening sensor 160, for example, in a manner capable of information communication.

[0048] The accelerator opening sensor 160 outputs a signal S_acc corresponding to the measured value. For example, the signal S_acc output from the accelerator opening sensor 160 is input to the input circuit 113 of the control device 110. In addition, the signal input to the control device 110 is not limited to Figure 2 The signals shown.

[0049] The input circuit 113 of the control device 110 sends the input signal to the input / output port 114. The input circuit 113 includes, for example, an A / D converter, and when the input signal includes an analog signal, the analog signal is converted into a digital signal by the A / D converter and sent to the input / output port 114. The value of the input signal sent from the input circuit 113 to the input / output port 114 is stored in the RAM constituting the storage device 112, and is used for the operation processing of the processing device 111. The computer program that specifies the content of the operation processing performed by the processing device 111 is recorded in, for example, the ROM constituting the storage device 112.

[0050] The processing device 111 calculates the requested torque of the engine 130 based on, for example, a signal S_acc corresponding to the measured value of the accelerator opening output from the accelerator opening sensor 160 or a signal output from another sensor. That is, the accelerator opening sensor 160 can be used as a requested torque detection sensor for detecting the requested torque of the engine 130. In addition, the processing device 111 calculates the control amount of each part of the engine system 100 based on the operating state of the engine 130 estimated from the outputs of various sensors provided in each part of the engine system 100.

[0051] Specifically, the processing device 111 calculates, for example, the control amount of each part of the engine system 100 as shown below based on the operating state of the engine 130. The processing device 111 calculates, for example, the opening θ of the throttle valve 125, the injection pulse period of the fuel injection device 134, the ignition timing of the spark plug 135, the opening and closing timing of the variable intake valve mechanism 132 and the variable exhaust valve mechanism 133, the opening of the EGR valve 146, and the like.

[0052] The processing device 111 records the calculated control amount of each part in the RAM constituting the storage device 112. In addition, the processing device 111 outputs the control amount of each part to the throttle drive circuit 115, the EGR valve drive circuit 116, the variable valve mechanism drive circuit 117, the fuel injection device drive circuit 118 and the ignition output circuit 119 via the input / output port 114, for example.

[0053] The throttle drive circuit 115 converts the opening θ of the throttle valve 125 inputted via the input / output port 114 into a control signal C_thr of the throttle valve 125, and outputs the signal to the throttle valve 125. The EGR valve drive circuit 116 converts the opening of the EGR valve 146 inputted via the input / output port 114 into a control signal C_egr of the EGR valve 146, and outputs the signal to the EGR valve 146.

[0054] The variable valve mechanism drive circuit 117 inputs the variable intake valve mechanism 132 and the opening and closing timing of the variable intake valve mechanism 132 via the input / output port 114, for example. The variable valve mechanism drive circuit 117 converts the input opening and closing timing into control signals C_ivt and C_evt of the variable intake valve mechanism 132 and the variable intake valve mechanism 132, and outputs them to the variable intake valve mechanism 132 and the variable exhaust valve mechanism 133.

[0055] The fuel injection device driving circuit 118 converts the injection pulse period of the fuel injection device 134 inputted via the input / output port 114 into a control signal C_fiv of the fuel injection device 134, and outputs it to the fuel injection device 134. The ignition output circuit 119 converts the ignition timing of the spark plug 135 inputted via the input / output port 114 into a control signal C_ign of the spark plug 135, and outputs it to the spark plug 135.

[0056] The engine system 100 generates a mixed air in the combustion chamber 131 by injecting fuel from the fuel injection device 134 to the air that is sucked into the intake pipe 121 and flows into the combustion chamber 131 via the throttle valve 125 and the variable intake valve mechanism 132. Then, the mixed air is combusted by ignition of the spark plug 135, and the piston is pressed downward by the combustion pressure, so that the engine 130 generates driving force.

[0057] The exhaust gas after the mixture in the combustion chamber 131 of the engine 130 is burned passes through the variable exhaust valve mechanism 133, the exhaust pipe 141, and the turbine 152, and is purified in the catalytic converter 142 to remove components such as NOx, CO, and HC, and then is discharged to the outside of the engine system 100. In addition, a part of the exhaust gas is recirculated to the intake pipe 121 via the EGR pipe 144, the EGR cooler 145, and the EGR valve 146.

[0058] Figure 3 yes Figure 2 1 is a functional block diagram of a control device 110 for an internal combustion engine according to the present embodiment.

[0059] The control device 110 includes, for example, a gas state calculation unit F1 , a mass flux calculation unit F2 , an opening area calculation unit F3 , an effective opening area calculation unit F4 , and a passing gas flow rate calculation unit F5 .

[0060] Each of these components of the control device 110 represents a function of the control device 110 that is realized by, for example, the processing device 111 executing a computer program stored in the storage device 112 .

[0061] That is, the gas state calculation part F1, the mass flux calculation part F2, the opening area calculation part F3, the effective opening area calculation part F4 and the gas flow calculation part F5 can be respectively translated as the calculation function of the gas state, the calculation function of the mass flux, the calculation function of the opening area, the calculation function of the effective opening area and the calculation function of the gas flow.

[0062] Below, we will refer to Figures 4 to 9 An example of the operation of the control device 110 for the internal combustion engine according to the present embodiment will be described. Figure 41 is a flowchart showing an example of a process flow for calculating the gas flow rate passing through the throttle valve 125 by the control device 110 of the internal combustion engine according to the present embodiment.

[0063] When to start Figure 4 In the process shown, the control device 110 first executes a process P1 of acquiring sensor information.

[0064] In the process P1, the control device 110 obtains the intake air temperature T_atm based on the output signal S_tmp of the intake air temperature sensor 123a, and obtains the atmospheric pressure P_atm based on the output S_oap of the atmospheric pressure sensor 137. In addition, in the process P1, the control device 110 obtains the rotation speed N_eng of the engine 130 based on the output signal S_cra of the crank angle sensor 136, and obtains the mass flow rate FR_mass of the intake air based on the output signal S_ifr of the mass flow meter 123.

[0065] Furthermore, in the process P1, the control device 110 obtains the opening θ of the throttle valve 125 based on the output signal S_thr of the throttle position sensor 125a. In the process P1, the control device 110 executes a program recorded in the storage device 112 by the processing device 111, for example, and processes the output signals of the various sensors input to the input circuit 113 and stored in the storage device 112, thereby being able to obtain the measurement results of the above-mentioned various sensors.

[0066] Next, the control device 110 executes a process P2 for calculating the temperature and pressure of the gas in the intake system 120. The control device 110 calculates the temperature and pressure of the gas in the intake system 120 by, for example, Figure 3 The gas state calculation unit F1 shown calculates the temperature and pressure of the gas in the intake system 120. For example, the gas state calculation unit F1 takes as input the intake temperature T_atm, atmospheric pressure P_atm, engine speed N_eng, intake air mass flow rate FR_mass, and throttle valve 125 opening θ obtained by the pre-processing P1.

[0067] The gas state calculation unit F1 calculates, based on the above input, for example, the temperature and pressure of the gas on the upstream side of the throttle valve 125, i.e., the upstream gas temperature Tu and the upstream gas pressure Pu, and the pressure of the gas on the downstream side of the throttle valve 125, i.e., the downstream gas pressure Pd.

[0068] In the present embodiment, the upstream side of the throttle valve 125 refers to, for example, a portion from the outlet of the intercooler 124 in the intake pipe 121 to the inlet of the throttle valve 125. In addition, the downstream side of the throttle valve 125 refers to, for example, a portion from the outlet of the throttle valve 125 in the intake pipe 121 to the inlet of the combustion chamber 131.

[0069] Here, in the control device 110 of the present embodiment, the basic principle of the intake system physical model is described, and the intake system physical model is used to estimate the behavior of air from the change of the opening degree θ of the throttle valve 125 to the change of the amount of inflow gas into the cylinder that flows into the combustion chamber 131 of the engine 130. Here, the path from the air intake port of the intake pipe 121 to the combustion chamber 131 of the engine 130 is divided into three control volumes (CV).

[0070] The first CV is, for example, the CV on the throttle upstream side from the intake port of the intake pipe 121 to the inlet of the throttle valve 125. The second CV is, for example, the CV on the downstream side of the throttle valve 125 from the outlet of the throttle valve 125 to the inlet of the combustion chamber 131 of the engine 130. The third CV is, for example, the CV of the combustion chamber 131 of the engine 130, that is, the cylinder.

[0071] In addition, the sensor detection values ​​acquired by the previous process P1, which include the intake air temperature T_atm, the atmospheric pressure P_atm, the mass flow rate FR_mass of the intake air, and the opening θ of the throttle valve 125, are used. Then, based on the basic equations of the following equations (1) to (4), the upstream side gas temperature Tu and the upstream side gas pressure Pu of the throttle valve 125 and the downstream side gas pressure Pd of the throttle valve 125 are calculated.

[0072] [Mathematical formula 2]

[0073]

[0074] In the above formulas (1) to (4), m is mass, e is energy, T is temperature, κ is specific heat ratio, R is gas constant, Q is heat, and V is volume. In addition, the subscripts in and out added to the mass m, specific heat ratio κ, and gas constant R respectively represent the flow into and out of the CV. That is, the gas state calculation unit F1 uses, for example, the gas flow rate and temperature calculated for each CV when operating one cycle ago to calculate the change in gas mass and the change in energy at the current moment. Next, the gas state calculation unit F1 calculates the temperature and pressure of each CV based on the calculated change in gas mass and energy.

[0075] Next, the control device 110 executes a process P3 for calculating the mass flux of the gas passing through the throttle valve 125. For example, the control device 110 calculates the mass flux of the gas passing through the throttle valve 125 by Figure 3 The mass flux calculation unit F2 shown in FIG. 1 calculates the mass flux MF of the gas passing through the throttle valve 125. The mass flux calculation unit F2 takes as input, for example, the gas temperature Tu and the gas pressure Pu on the upstream side of the throttle valve 125 and the gas pressure Pd on the downstream side of the throttle valve 125 calculated in the previous process P2.

[0076] The mass flux calculation unit F2 calculates, for example, the mass flow rate per unit area passing through the throttle valve 125, that is, the mass flux MF, based on the above-mentioned input. Here, for example, the mass flux calculation unit F2 regards the throttle valve 125 as a channel and constructs a fluid dynamics model around the throttle to calculate the mass flux of the gas passing through the throttle valve 125. The mass flux calculation unit F2 calculates the mass flux MF based on, for example, the upstream gas temperature Tu of the throttle valve 125, the upstream gas pressure Pu and the downstream gas pressure Pd before and after the throttle valve 125 stored in the storage device 112, and the following equations (5) to (7).

[0077] [Mathematical formula 3]

[0078]

[0079] In the above formula (5), R is a gas constant and ψ is a flow coefficient. In the above formulas (6) and (7), κ is a specific heat ratio. The flow coefficient ψ is selected from either of the above formulas (6) and (7) according to the ratio Pd / Pu of the gas pressure Pd on the downstream side of the throttle valve 125 to the gas pressure Pu on the upstream side.

[0080] Next, the control device 110 executes a process P4 for calculating the opening area A of the throttle valve 125. The control device 110 calculates the opening area A of the throttle valve 125 by, for example, Figure 3 The opening area calculation unit F3 shown calculates the geometric opening area A based on the opening θ of the throttle valve 125. The opening area calculation unit F3 takes the opening θ of the throttle valve 125 acquired in the process P1 of acquiring the sensor information as input, calculates and outputs the geometric opening area A of the throttle valve 125. The geometric opening area A of the throttle valve 125 can be uniquely obtained based on the opening θ of the throttle valve 125.

[0081] In the control device 110 of the present embodiment, for example, a table generated based on the relationship between the opening degree θ of the throttle valve 125 and the geometric opening area A is stored in advance in the storage device 112. The opening area calculation unit F3, for example, receives the opening degree θ of the throttle valve 125 as an input, and outputs the geometric opening area A of the throttle valve 125 corresponding to the input opening degree θ by referring to the above table stored in the storage device 112. By using such a table, the calculation load of the processing device 111 can be reduced.

[0082] For example, in a low opening range where the opening θ of the throttle valve 125 is 15° or less, the above table can define the relationship between the opening θ and the geometric opening area A at a narrower angle interval than in a high opening range. This is because the lower the opening of the throttle valve 125, the greater the change in the geometric opening area A with respect to the opening θ. Therefore, even if the opening θ of the throttle valve 125 is a low opening, the geometric opening area A can be estimated with high accuracy.

[0083] Next, the control device 110 executes a process P5 for calculating the effective opening area EA of the throttle valve 125. For example, the control device 110 performs a process P5 for calculating the effective opening area EA of the throttle valve 125. Figure 3 The effective opening area calculation unit F4 shown in the figure calculates the effective opening area EA of the throttle valve 125. The effective opening area calculation unit F4, for example, receives as input the opening degree θ of the throttle valve 125 acquired in the process P1 of acquiring the above-mentioned sensor information, and the upstream gas pressure Pu and the downstream gas pressure Pd of the throttle valve 125 as outputs of the gas state calculation unit F1. In addition, the effective opening area calculation unit F4 receives as input the geometric opening area A of the throttle valve 125 as output of the opening area calculation unit F3.

[0084] Figure 5 yes Figure 3 Detailed functional block diagram of the effective opening area calculation unit F4 shown in FIG. The effective opening area calculation unit F4 includes, for example, a pressure difference calculation unit F41, a correction coefficient calculation unit F42, and a correction unit F43. In addition, each unit of the effective opening area calculation unit F4 also represents the function of the control device 110 implemented by the processing device 111 executing the computer program stored in the storage device 112, similarly to the effective opening area calculation unit F4. That is, the pressure difference calculation unit F41, the correction coefficient calculation unit F42, and the correction unit F43 can be respectively referred to as a pressure difference calculation function, a correction coefficient calculation function, and a correction function.

[0085] For example, the differential pressure calculation unit F41 takes the upstream gas pressure Pu and the downstream gas pressure Pd of the throttle valve 125 as inputs, and calculates the difference between the upstream gas pressure Pu and the downstream gas pressure Pd, that is, the front-rear differential pressure ΔP of the throttle valve 125. The correction coefficient calculation unit F42 takes the front-rear differential pressure ΔP of the throttle valve 125, which is the output of the differential pressure calculation unit F41, and the opening θ of the throttle valve 125 as inputs. Based on these inputs, the correction coefficient calculation unit F42 calculates the correction coefficient μ for correcting the geometric opening area A of the throttle valve 125 to the effective opening area EA.

[0086] More specifically, the correction coefficient calculation unit F42 calculates the correction coefficient μ based on a function that specifies the relationship between the pressure difference ΔP across the throttle valve 125 and the correction coefficient μ. In addition, it is usually difficult to imagine that the effective opening area EA of the throttle valve 125 is larger than the geometric opening area A of the throttle valve 125, so the correction coefficient μ is set within a range of not less than 0 and not more than 1.0.

[0087] Figure 6 : is a graph showing an example of a function that specifies the relationship between the pressure difference ΔP across the throttle valve 125 and the correction coefficient μ. Figure 6In the example shown, the correction coefficient μ and the differential pressure ΔP across the throttle valve 125 are, for example, proportionally related with a positive correlation, and have a relationship represented by the function of the following equation (8).

[0088] μ=a i ΔP+b i · · · (8)

[0089] like Figure 6 As shown in FIG. 1 , for example, a plurality of functions for defining the relationship between the pressure difference ΔP and the correction coefficient μ are defined according to the opening θ of the throttle valve 125. Figure 6 In the example shown, the opening degrees θ of the throttle valve 125, that is, the magnitude relationship between θ1 to θ4 is θ1<θ2<θ3<θ4. Figure 6 In the example shown, the slope of the correction coefficient μ, i.e., the ratio of the correction coefficient μ to the change in the pressure difference ΔP, increases as the opening θ of the throttle valve 125 increases. That is, the ratio of the change in the correction coefficient μ to the change in the pressure difference ΔP has a positive correlation with the opening θ.

[0090] The function that specifies the relationship between the pressure difference ΔP of the throttle valve 125 and the correction coefficient μ may be specified at equal angular intervals from the opening θ of the throttle valve 125 from fully closed to fully open, or may be specified at different angular intervals according to the operating region of the engine 130. More specifically, for example, in a low opening region where the opening θ of the throttle valve 125 is 15° or less, the above function may be specified at narrower angular intervals than in other regions. Thus, the storage device 112 of the control device 110 can be effectively used.

[0091] like Figure 6 As shown, a plurality of functions are obtained in advance, for example, by experiments using the engine system 100 and stored in the storage device 112, and the plurality of functions define the relationship between the pressure difference ΔP and the correction coefficient μ for each opening degree θ of the throttle valve 125. In addition, the correction coefficient μ can be obtained using, for example, various numerical values ​​obtained in experiments of the engine system 100 and the following formula (9).

[0092] [Formula 4]

[0093]

[0094] In the above formula (9), dm / dt is the mass of gas flowing into the throttle valve 125 per unit time. A is the geometric opening area of ​​the throttle valve 125. Pu and Pd are the pressures of the gas on the upstream side and downstream side of the throttle valve 125, respectively. Tu is the gas temperature on the upstream side of the throttle valve 125. R is the gas constant, and ψ is the flow coefficient. The flow coefficient ψ is selected from any of the above formulas (6) and (7) according to the ratio Pd / Pu of the gas pressure Pd on the downstream side of the throttle valve 125 to the gas pressure Pu on the upstream side.

[0095] In the process P5 of calculating the effective opening area EA of the throttle valve 125, Figure 5 The correction coefficient calculation unit F42 shown takes, for example, the opening degree θ and the front-rear pressure difference ΔP of the throttle valve 125 as inputs. The correction coefficient calculation unit F42 then selects a function corresponding to the input opening degree θ from a plurality of functions stored in the storage device 112, and calculates the correction coefficient μ based on the input pressure difference ΔP and the selected function.

[0096] Here, we will refer to Figure 7 and Figure 8 , the relationship between the opening degree θ of the throttle valve 125 and the correction coefficient μ for correcting the geometric opening area A of the throttle valve 125 to the effective opening area EA will be described.

[0097] Figure 7 : is a graph showing the relationship between the opening degree θ of the throttle valve 125 and the correction coefficient μ. Figure 7 The relationship shown is obtained by, for example, changing the rotation speed and torque of the engine 130, measuring the opening of the throttle valve 125, the flow rate of the gas passing through the throttle valve 125, the pressure of the gas on the upstream and downstream sides of the throttle valve 125, and the temperature of the gas on the downstream side in a stable state, using the above formula (9). Figure 7 As shown, the correction coefficient μ takes a scattered value with respect to the opening degree θ of the throttle valve 125 , and cannot be uniquely determined for the opening degree θ of the throttle valve 125 .

[0098] Figure 8 Schematic diagram of the airflow passing through the throttle valve 125. The throttle valve 125 is, for example, a butterfly valve, and its opening θ is completely closed at 0°, and its opening θ is completely open at 90°. If the opening θ of the throttle valve 125 is reduced, the airflow passing through the throttle valve 125 increases in flow velocity and decreases in pressure when passing through the opening of the throttle valve 125 whose opening area is squeezed by the valve body. Furthermore, after passing through the opening of the throttle valve 125, due to the rapid expansion of the pipeline, the pressure increases, and a part of the airflow is separated, generating stagnation BW, jet JF, and vortex VX.

[0099] As a result, the opening area of ​​the geometric opening area A through which the gas actually flows to the throttle valve 125, that is, the effective opening area EA, is reduced. That is, the effective opening area EA changes according to the states of the upstream gas pressure Pu and the downstream gas pressure Pd before and after the throttle valve 125. Therefore, in this embodiment, based on the Navier-Stokes equation, the point that the fluid driving force causes a pressure difference is focused on. Figure 6 As shown, Figure 7 The correction coefficient μ shown is organized as a function that defines the relationship between the correction coefficient μ and the differential pressure ΔP across the throttle valve 125 according to the opening degree θ of the throttle valve 125 .

[0100] like Figure 6 As shown, if the opening θ of the throttle valve 125 is constant, the correction coefficient μ is positively correlated with the pressure difference ΔP and is proportional. In addition, if the opening θ of the throttle valve 125 increases, the slope of the first-order approximation of the correction coefficient μ increases. This is considered to be due to the fact that under the condition that the opening θ of the throttle valve 125 is constant, the flow rate, that is, the flow velocity of the gas changes, the Reynolds number changes, and the separation, stagnation BW, jet JF, vortex VX, etc. of the gas flow occur near the valve body of the throttle valve 125, resulting in a change in the correction coefficient μ. In addition, in fluid mechanics, there is the following correlation: as the gas flow velocity near the valve body of the throttle valve 125 increases, the pressure difference ΔP before and after the throttle valve 125 also increases, so it is believed that such a result is caused.

[0101] In addition, in the present embodiment, the correction coefficient μ is arranged with the pressure difference ΔP before and after the throttle valve 125 as the axis, but the correction coefficient μ may be arranged with the pressure ratio Pd / Pu upstream and downstream of the throttle valve 125 as the axis. In this case, if the opening θ of the throttle valve 125 is constant, the correction coefficient μ has a negative correlation and is proportional to the pressure ratio Pd / Pu, and if the opening θ of the throttle valve 125 increases, the slope of the first-order approximation of the correction coefficient μ decreases. As described above, Figure 5 The correction coefficient calculation unit F42 shown can estimate the correction coefficient μ using the upstream gas pressure Pu and downstream gas pressure Pd of the throttle valve 125 , the pressure difference ΔP, and the opening degree θ of the throttle valve 125 .

[0102] also, Figure 5 The correction unit F43 shown in the figure takes as input the geometric opening area A of the throttle valve 125 as the output of the opening area calculation unit F3 and the correction coefficient μ as the output of the correction coefficient calculation unit F42, and calculates the effective opening area EA of the throttle valve 125. The correction unit F43 calculates the effective opening area EA of the throttle valve 125 by, for example, multiplying the geometric opening area A of the throttle valve 125 by the correction coefficient μ (EA=μ×A). Thus, the process P5 for calculating the effective opening area EA of the throttle valve 125 ends. Figure 4 The effective opening area EA of the throttle valve 125 is shown.

[0103] Next, the control device 110 executes a process P6 for calculating the flow rate of the gas passing through the throttle valve 125. For example, the control device 110 calculates the flow rate of the gas passing through the throttle valve 125. Figure 3 The gas flow rate calculation unit F5 shown calculates the gas flow rate GF passing through the throttle valve 125 by taking the mass flux MF as the output of the mass flux calculation unit F2 and the effective opening area EA as the output of the effective opening area calculation unit F4 as inputs.

[0104] Specifically, the gas flow rate GF passing through the throttle valve 125 is calculated by the gas flow rate calculation unit F5 by multiplying the mass flux MF of the gas passing through the throttle valve 125 by the effective opening area EA of the throttle valve 125 (GF=MF×EA). Figure 4 The control device 110 estimates the cylinder inflow gas amount, that is, the gas amount flowing into the combustion chamber 131 of the engine 130 based on the gas flow rate GF passing through the throttle valve 125 calculated in the processes P1 to P6.

[0105] Next, the operation of the internal combustion engine control device 110 according to the present embodiment will be described.

[0106] From the perspective of reducing the environmental burden, the regulations on automobile exhaust have tended to be stricter in recent years. In order to cope with such strict regulations, it is necessary to improve the accuracy of the air-fuel ratio control of the engine 130 constituting the engine system 100. In order to achieve high accuracy in the air-fuel ratio control of the engine 130, it is required to estimate the amount of air flowing into the combustion chamber 131 of the engine 130, that is, the amount of gas flowing into the cylinder, with high accuracy even in the transient state of the engine, such as when the automobile is rapidly accelerated or rapidly decelerated. This is because by estimating the amount of gas flowing into the cylinder with high accuracy, the fuel injection amount that can achieve the target air-fuel ratio with high accuracy can be set.

[0107] As described above, the control device 110 of the internal combustion engine of the present embodiment includes the mass flux calculation unit F2, the opening area calculation unit F3, the effective opening area calculation unit F4, and the passing gas flow rate calculation unit F5. The mass flux calculation unit F2 calculates the mass flux MF of the gas passing through the throttle valve 125 based on the upstream gas temperature Tu, the upstream gas pressure Pu, and the downstream gas pressure Pd of the throttle valve 125. The opening area calculation unit F3 calculates the opening area A of the throttle valve 125 based on the opening degree θ of the throttle valve 125. The effective opening area calculation unit F4 calculates the effective opening area EA of the throttle valve 125 based on the upstream gas pressure Pu, the downstream gas pressure Pd, the opening degree θ, and the opening area A. The passing gas flow rate calculation unit F5 calculates the gas flow rate GF passing through the throttle valve 125 based on the mass flux MF and the effective opening area EA.

[0108] With such a configuration, the control device 110 of the internal combustion engine of the present embodiment can estimate the gas flow rate GF passing through the throttle valve 125 with high accuracy, and can estimate the amount of gas flowing into the cylinder of the engine 130 with higher accuracy than before. More specifically, even in a transient state of the engine 130, such as when the vehicle is rapidly accelerated or rapidly decelerated, the effective opening area EA of the throttle valve 125 can be estimated with high accuracy based on the upstream gas pressure Pu, the downstream gas pressure Pd, the opening θ, and the geometric opening area A of the throttle valve 125. As a result, the gas flow rate GF passing through the throttle valve 125 can be estimated with high accuracy based on the mass flux MF and the effective opening area EA, and the amount of gas flowing into the cylinder can be estimated with high accuracy. Therefore, the fuel injection amount that realizes the target air-fuel ratio with high accuracy can be set in the engine 130, and it is possible to cope with the strict regulation of exhaust emissions.

[0109] Fig. 9 Graphs showing time changes in the opening θ of the throttle valve 125, the upstream gas pressure Pu, the downstream gas pressure Pd, and the effective opening area EA during deceleration. In addition, in each graph of the upstream gas pressure Pu, the downstream gas pressure Pd, and the effective opening area EA, the solid line represents the actual upstream gas pressure Pu, the downstream gas pressure Pd, and the effective opening area EA. In addition, the dotted line represents the estimated value of each value obtained based on the control device of the conventional internal combustion engine, and the single-dot chain line represents the estimated value of each value obtained based on the control device 110 of the internal combustion engine involved in this embodiment.

[0110] At time t0, the throttle valve 125 begins to close, and the opening θ decreases. Conventional control devices for internal combustion engines calculate the effective opening area EA of the throttle valve 125 based on the opening θ of the throttle valve 125. Therefore, in conventional control devices for internal combustion engines, the estimated value of the effective opening area EA shown by the dotted line depends only on the opening θ of the throttle valve 125. When the pressure difference between the upstream gas pressure Pu and the downstream gas pressure Pd of the throttle valve 125 is too large, the error from the actual effective opening area EA shown by the solid line increases. In addition, in conventional control devices for internal combustion engines, the estimated value of the downstream gas pressure Pd of the throttle valve 125 shown by the dotted line is also an estimated value that is too large relative to the actual downstream gas pressure Pd shown by the solid line.

[0111] On the contrary, the control device 110 of the internal combustion engine of the present embodiment calculates the effective opening area EA based on the opening θ of the throttle valve 125, the upstream gas pressure Pu, and the downstream gas pressure Pd as described above. Therefore, in the control device 110 of the internal combustion engine of the present embodiment, the estimated value of the effective opening area EA shown by the single-point chain line is very consistent with the actual effective opening area EA shown by the solid line.

[0112] In addition, in the control device 110 of the internal combustion engine of the present embodiment, the estimated value of the downstream gas pressure Pd shown by the single-dot chain line is very consistent with the actual downstream gas pressure Pd shown by the solid line. Therefore, the gas flow rate GF passing through the throttle valve 125 can be estimated with high accuracy, and the amount of gas flowing into the cylinder of the engine 130 can be estimated with high accuracy. As a result, the exhaust air-fuel ratio can be improved to be rich. In addition, according to the control device 110 of the internal combustion engine of the present embodiment, it is possible to prevent the downstream gas pressure Pd of the throttle valve 125 from being estimated to be too small during acceleration, thereby improving the exhaust air-fuel ratio to be lean.

[0113] As described above, according to the present embodiment, the effective opening area calculation unit F4 is included, and the geometric opening area A is multiplied and corrected based on the upstream gas pressure Pu and the downstream gas pressure Pd of the throttle valve 125, so that the effective opening area EA can be correctly estimated even in the transient state of the engine 130, and the gas flow rate GF passing through the throttle valve 125 can be estimated with high accuracy. Therefore, according to the present embodiment, the present invention can provide a control device 110 for an internal combustion engine, which can estimate the amount of gas flowing into the cylinder with high accuracy, can control the appropriate fuel injection amount according to the amount of gas flowing into the cylinder, and can improve fuel consumption and exhaust emissions.

[0114] In addition, in the control device 110 of the internal combustion engine of the present embodiment, the effective opening area calculation unit F4 includes a pressure difference calculation unit F41, a correction coefficient calculation unit F42, and a correction unit F43. The pressure difference calculation unit F41 calculates the pressure difference ΔP between the upstream gas pressure Pu and the downstream gas pressure Pd. The correction coefficient calculation unit F42 calculates the correction coefficient μ for correcting the opening area A to the effective opening area EA based on the pressure difference ΔP and the opening degree θ. The correction unit F43 obtains the effective opening area EA by multiplying the opening area A by the correction coefficient μ.

[0115] With this configuration, the effective opening area calculation unit F4 can estimate the correction coefficient μ for correcting the geometric opening area A of the throttle valve 125 to the effective opening area EA based on the upstream gas pressure Pu, the downstream gas pressure Pd, and the opening θ of the throttle valve 125. In addition, the effective opening area calculation unit F4 can calculate the effective opening area EA by multiplying the geometric opening area A of the throttle valve 125 by the correction coefficient μ. Therefore, even under the condition that the pressure state before and after the throttle valve 125 changes in the transient state of the engine 130, the effective opening area calculation unit F4 can appropriately calculate the correction coefficient μ and the effective opening area EA. Therefore, even in the transient state of the engine 130, the gas flow rate GF passing through the throttle valve 125 can be calculated with high accuracy by the gas flow rate calculation unit F5. As a result, the downstream gas pressure Pd of the throttle valve 125 can be calculated more accurately, and the amount of gas flowing into the cylinder can be estimated with high accuracy.

[0116] Furthermore, in the control device 110 of the internal combustion engine of the present embodiment, the correction coefficient calculation unit F42 calculates the correction coefficient μ based on the relationship between the pressure difference ΔP set according to the opening θ of the throttle valve 125 and the correction coefficient μ. Therefore, even if the opening θ of the throttle valve 125 changes according to the operating conditions of the engine 130, the effective opening area EA can be estimated with high accuracy. More specifically, as described above, by functionalizing the relationship between the correction coefficient μ and the pressure difference ΔP for each opening θ of the throttle valve 125, even when the opening θ changes suddenly and the pressure before and after the throttle valve 125 changes, the correction coefficient μ can be accurately estimated.

[0117] In addition, in the control device 110 of the internal combustion engine of the present embodiment, the relationship between the differential pressure ΔP across the throttle valve 125 and the correction coefficient μ is a proportional relationship having a positive correlation. In other words, the correction coefficient μ increases as the differential pressure ΔP across the throttle valve 125 increases. Therefore, even if the differential pressure ΔP changes according to the operating conditions of the engine 130 under the condition that the opening θ of the throttle valve 125 is constant, the effective opening area EA can be estimated with high accuracy.

[0118] In addition, in the control device 110 of the internal combustion engine of the present embodiment, the ratio of the change in the correction coefficient μ to the change in the differential pressure ΔP across the throttle valve 125 has a positive correlation with the opening θ. That is, as the opening θ of the throttle valve 125 increases, the slope of the correction coefficient μ as a function of the differential pressure ΔP increases. Therefore, as the opening θ of the throttle valve 125 increases, the correction coefficient μ can be made larger, and even if the opening θ of the throttle valve 125 changes with the operating conditions of the engine 130, the effective opening area EA of the throttle valve 125 can be estimated with high accuracy.

[0119] In addition, the control device 110 of the internal combustion engine of the present embodiment uses the upstream gas temperature Tu, the upstream gas pressure Pu, and the downstream gas pressure Pd, which are estimated values ​​obtained based on the gas state calculation unit F1, as the upstream gas temperature, the upstream gas pressure, and the downstream gas pressure of the throttle valve 125. However, the control device 110 may use, for example, the upstream gas temperature, the upstream gas pressure, and the downstream gas pressure of the throttle valve 125 detected by the intake air temperature sensor 123a, the atmospheric pressure sensor 137, and the intake pipe pressure sensor 126. Therefore, even in the case where the gas state calculation unit F1 is not provided, the upstream gas temperature, the upstream gas pressure, and the downstream gas pressure of the throttle valve 125 can be obtained.

[0120] In addition, there is a correlation between the gas pressure on the downstream side of the throttle valve 125 and the rotation speed N_eng of the engine 130 and the opening degree θ of the throttle valve 125 or the load (torque) of the engine 130. Therefore, the gas pressure on the downstream side of the throttle valve 125 can be provided, for example, by a map having as axes the rotation speed N_eng of the engine 130 and the opening degree θ of the throttle valve 125 or the rotation speed N_eng of the engine 130 and the load of the engine 130. Therefore, even without the atmospheric pressure sensor 137, the intake pipe pressure sensor 126 and the gas state calculation unit F1, the gas pressure on the downstream side of the throttle valve 125 can be calculated.

[0121] In addition, if Figure 6 As shown, the control device 110 of the internal combustion engine of the present embodiment uses a method of functionalizing the relationship between the pressure difference ΔP before and after the throttle valve 125 and the correction coefficient μ, but a map that specifies the relationship between the pressure difference ΔP and the opening θ of the throttle valve 125 may be set. Thus, the correction coefficient μ can be accurately calculated by simple processing. In addition, the control device 110 can calculate the correction coefficient μ using, for example, the pressure ratio Pd / Pu between the upstream gas pressure Pu and the downstream gas pressure Pd of the throttle valve 125, and the opening θ of the throttle valve 125. The correction coefficient μ is approximated by the pressure difference ΔP before and after the throttle valve 125 or the pressure ratio Pd / Pu, and a parameter with higher approximation accuracy is used, so that the correction coefficient μ can be estimated with higher accuracy.

[0122] [Implementation Method 2]

[0123] Below, quoting Figures 1 to 3 as well as Figures 5 to 8 , and refer to Fig.10 and Fig.11 Embodiment 2 of the control device for an internal combustion engine of the present disclosure will be described. Fig.10 1 is a flowchart showing an example of a process flow for calculating the gas flow rate GF passing through the throttle valve 125 by the control device for the internal combustion engine according to the present embodiment.

[0124] The control device of the internal combustion engine of the present embodiment is different from the control device 110 of the above-mentioned embodiment 1 in that machine learning is performed in consideration of the influence of dirt attached to the periphery of the valve body of the throttle valve 125. The other structures of the control device of the present embodiment are the same as those of the control device 110 of the embodiment 1, and therefore the same parts are marked with the same reference numerals and the description thereof is omitted.

[0125] Fig.10 The processing from process P1 to process P3 performed by the control device of this embodiment shown in FIG. Figure 4 The processes from process P1 to process P3 performed by the control device 110 in the illustrated first embodiment are the same.

[0126] After the process P3 of calculating the mass flux MF of the gas passing through the throttle valve 125 is completed, the control device of the present embodiment executes the next processes P7 to P12.

[0127] In process P7, the control device, for example, Figure 1 The detection value Pds of the gas pressure on the downstream side of the throttle valve 125 detected by the intake pipe pressure sensor 126 and the downstream gas pressure Pd as the output of the gas state calculation unit F1 are input to the effective opening area calculation unit F4. In the process P7, for example, the effective opening area calculation unit F4 calculates the absolute value Dp of the difference between the detection value Pds of the gas pressure on the downstream side of the throttle valve 125 and the downstream gas pressure Pd as the estimated value thereof, which is the difference between the detection value Pds of the gas pressure on the downstream side of the throttle valve 125 and the downstream gas pressure Pd as the estimated value thereof.

[0128] Next, in processing P8, for example, the effective opening area calculation unit F4 determines whether the following multiple learning update conditions are met. Condition 1: The corrected pseudo value Ad of the geometric opening area A of the throttle valve 125 and the corrected pseudo value θd of the opening θ are learned within a specified period. Condition 2: The absolute value Dp(n) of the difference between the detected value Pds of the downstream side gas pressure of the throttle valve 125 calculated in this processing and the downstream side gas pressure Pd as its estimated value is less than the absolute value Dp(n-1) of the difference calculated in the previous processing (Dp(n)<Dp(n-1)). Condition 3: It is a steady-state operation state in which the change in mass flux FR_mass is less than a specified threshold.

[0129] By setting the above condition 2, it is possible to determine whether the difference between the detected value Pds of the downstream gas pressure of the throttle valve 125 and the downstream gas pressure Pd as its estimated value has been reduced by learning. Therefore, the learning value can be updated only when there is a learning effect, thereby preventing learning failure. In addition, by setting the above condition 3, the learning value can be updated under more stable operating conditions, thereby improving the learning accuracy.

[0130] In process P8, for example, the effective opening area calculation unit F4 determines the above-mentioned multiple learning update conditions, and if determined to be satisfied (YES), executes process P9 to update the learning value, and if determined not to be satisfied (NO), executes process P10 to reset the learning value.

[0131] In processing P9, for example, the effective opening area calculation unit F4 stores the correction pseudo value Ad of the geometric opening area A and the correction pseudo value θd of the opening θ of the throttle valve 125 in the storage device 112 as the correction value Av of the opening area A and the correction value θv of the opening θ, respectively.

[0132] On the other hand, in the process P10 , for example, the effective opening area calculation unit F4 resets the correction pseudo value Ad of the geometric opening area A and the correction pseudo value θd of the opening degree θ of the throttle valve 125 to zero, respectively.

[0133] Next, in the process P11, for example, the effective opening area calculation unit F4 determines whether the following multiple learning execution conditions are satisfied. Condition 1: The absolute value Dp of the difference between the detected value Pds of the downstream side gas pressure of the throttle valve 125 and the downstream side gas pressure Pd as the estimated value thereof is greater than a threshold value. Condition 2: It is a transient operation state in which the change in the mass flux FR_mass is greater than a predetermined threshold value.

[0134] Here, there is a correlation between the gas pressure on the downstream side of the throttle valve 125 and the amount of gas flowing into the cylinder, which is the amount of gas flowing into the combustion chamber 131 of the engine 130. Therefore, when there is a deviation between the downstream gas pressure Pd, which is an estimated value of the gas pressure on the downstream side of the throttle valve 125, and the detected value Pds of the downstream gas pressure, which is a detected value of the intake pipe pressure sensor 126, an error may occur in the estimation of the gas flow rate GF passing through the throttle valve 125.

[0135] Therefore, as the learning execution condition in the above-mentioned process P11, the above-mentioned condition 1 is set.

[0136] In Condition 1 of the learning execution condition, for example, the difference between the exhaust air-fuel ratio detected by the air-fuel ratio sensor 143 and the target air-fuel ratio may be set as a threshold. In addition, by setting Condition 2 as the learning execution condition in the above-mentioned process P11, learning is appropriately performed under the condition that the estimation error of the inflow gas amount in the cylinder is larger than the estimated value, thereby improving the learning accuracy. In addition, as Condition 2 of the learning execution condition, the change speed of the opening degree θ of the throttle valve 125 may be used to determine the transient operating state.

[0137] In the process P11 , for example, when the effective opening area calculation unit F4 determines that the above-mentioned plurality of learning execution conditions are satisfied (YES), the effective opening area calculation unit F4 executes the process P12 for executing learning.

[0138] For example, if the effective opening area calculation unit F4 determines that the above-mentioned multiple learning execution conditions are not met (NO), it executes processing P4 in the same manner as the above-mentioned embodiment 1, and the processing P4 calculates the geometric opening area A of the throttle valve 125 through the opening area calculation unit F3.

[0139] In the process P12, for example, the effective opening area calculation unit F4 calculates the correction pseudo value Ad of the geometric opening area A of the throttle valve 125 and the correction pseudo value θd of the opening degree θ of the throttle valve 125. Here, the absolute value Dp of the difference between the detected value Pds of the downstream side gas pressure of the throttle valve 125 and the downstream side gas pressure Pd which is the estimated value thereof, and the correction pseudo values ​​Ad and θd of the opening area A and the opening degree θ corresponding to the opening degree θ of the throttle valve 125 at that time are calculated.

[0140] More specifically, as shown in Table 1 below, the absolute value Dp of the difference between the detected value Pds of the gas pressure on the downstream side of the throttle valve 125 and the gas pressure on the downstream side Pd as the estimated value thereof is divided into a plurality of regions. Then, the correction pseudo value Ad, θd is set for each region of the absolute value Dp of the difference. In Table 1 below, the larger the absolute value Dp of the difference is, the larger the correction pseudo value Ad, θd is set. That is, in Table 1 below, Dp1<Dp2<Dp3, A1<A2<A3, θ1<θ2<θ3 is established.

[0141] [Table 1]

[0142]

[0143] Therefore, in the initial stage of learning when the absolute value Dp of the difference between the detected value Pds of the downstream gas pressure of the throttle valve 125 and the estimated value of the downstream gas pressure Pd is large, the correction amount becomes large, and as the learning proceeds, if the absolute value Dp of the difference decreases, the correction amount becomes small. This can prevent learning failure.

[0144] Next, in process P4, similarly to the first embodiment, the control device performs, for example, Figure 3 The opening area calculation unit F3 shown calculates the geometric opening area based on the opening degree θ of the throttle valve 125. In addition, in the process P4, the control device of the present embodiment calculates the corrected opening area Ac=A-Av by, for example, subtracting the correction value Av from the opening area A calculated by the opening area calculation unit F3 through the effective opening area calculation unit F4.

[0145] Here, the correction value Av of the opening area A is a positive value, and the corrected opening area Ac is smaller than the geometric opening area A of the throttle valve 125. Therefore, by making the corrected opening area Ac smaller than the geometric opening area A, even if the actual opening area with respect to the opening degree θ of the throttle valve 125 becomes smaller due to, for example, contamination of the valve body of the throttle valve 125, the opening area of ​​the throttle valve 125 can be appropriately calculated.

[0146] Furthermore, in the process P5 of calculating the effective opening area of ​​the throttle valve 125, the control device of the present embodiment calculates the corrected opening θc of the throttle valve 125. More specifically, the control device calculates the corrected opening θc=θ-θv by, for example, subtracting the correction value θv from the opening θ of the throttle valve 125 through the effective opening area calculation unit F4. Here, the correction value θv of the opening θ is a positive value, and the corrected opening θc is smaller than the actual opening θ of the throttle valve 125.

[0147] Then, the effective opening area calculation unit F4 uses the corrected opening θc instead of the actual opening θ of the throttle valve 125 to calculate the correction coefficient μ in the same manner as in the first embodiment. Figure 6 The graph shown allows for a more accurate calculation of the correction factor μ.

[0148] Furthermore, the effective opening area calculation unit F4 uses the corrected opening area Ac, and similarly to the first embodiment, multiplies the corrected opening area Ac by the correction coefficient μ to calculate the effective opening area EA.

[0149] Therefore, even if the actual opening area of ​​the throttle valve 125 is reduced due to dirt around the valve body of the throttle valve 125, the effective opening area EA can be calculated taking into account the influence of the correction coefficient μ. Therefore, in the next process P6, the gas flow rate GF passing through the throttle valve 125 can be calculated more accurately.

[0150] Hereinafter, the operation of the control device for the internal combustion engine according to the present embodiment will be described. Fig.11 It is a graph showing the opening θ of the throttle valve 125 during deceleration, the mass flow rate FR_mass of the gas, the downstream gas pressure Pd and its detection value Pds, the absolute value Dp of the difference between the downstream gas pressure Pd and its detection value Pds, the corrected pseudo value Ad of the opening area A, the corrected pseudo value θd of the opening θ, and the time variation of the effective opening area EA.

[0151] In addition, in the graph of the downstream gas pressure Pd and its detection value Pds, the solid line represents the detection value Pds of the downstream gas pressure, the dotted line represents the downstream gas pressure Pd before the learning value is updated, and the single-point chain line represents the downstream gas pressure Pd after the learning value is updated. In addition, in the graph of the effective opening area EA, the solid line represents the effective opening area EA before the learning value is updated, and the dotted line represents the effective opening area EA after the learning value is updated.

[0152] At time t0, the throttle valve 125 starts to close, the opening θ decreases, and the detection value Pds of the gas pressure on the downstream side of the throttle valve 125 starts to decrease. Then, the difference Dp between the downstream gas pressure Pd before the learning value update shown by the dotted line and the detection value Pds of the gas pressure on the downstream side of the throttle valve 125 increases, and reaches or exceeds the threshold value Dpt at time t1, and the learning execution condition in the above-mentioned process P11 is satisfied.

[0153] Therefore, in the above-mentioned process P12, the correction pseudo value Ad of the geometric opening area A of the throttle valve 125 and the correction pseudo value θd of the opening θ of the throttle valve 125 are calculated. As a result, learning is performed, the learning value is updated, and the effective opening area EA is corrected in the direction of decreasing the effective opening area EA as shown by the dotted line in the graph.

[0154] As described above, the control device of the internal combustion engine of the present embodiment learns at least one of the correction value Av of the opening area A and the correction value θv of the opening degree θ based on the downstream side gas pressure Pd which is an estimated value of the downstream side gas pressure of the throttle valve 125 and the detection value Pds of the downstream side gas pressure obtained based on the intake pipe pressure sensor 126.

[0155] According to this configuration, even when the actual opening area A is reduced due to dirt attached to the periphery of the valve body of the throttle valve 125, the control device of the internal combustion engine of the present embodiment can calculate the correct effective opening area EA, thereby calculating the gas flow rate GF passing through the throttle valve 125. Therefore, the amount of gas flowing into the cylinder of the engine 130 can be estimated with high accuracy, and deterioration of fuel consumption rate and exhaust emission can be prevented.

[0156] Furthermore, when the difference Dp between the downstream gas pressure Pd as an estimated value and the detected value Pds of the downstream gas pressure is greater than or equal to a threshold value, the control device of the internal combustion engine of the present embodiment learns at least one of the correction value Av of the opening area A and the correction value θv of the opening degree θ. With such a configuration, the control device of the internal combustion engine of the present embodiment can prevent the difference Dp between the downstream gas pressure Pd as an estimated value and the detected value Pds of the downstream gas pressure from exceeding the threshold value.

[0157] In addition, the control device of the internal combustion engine of the present embodiment calculates the effective opening area EA using at least one of the corrected opening area Ac obtained by subtracting the correction value Av of the opening area A from the opening area A and the corrected opening degree θc obtained by subtracting the correction value θv of the opening degree θ from the opening degree θ. With such a mechanism, the control device of the internal combustion engine of the present embodiment can calculate the effective opening area EA more accurately even when, for example, the actual opening area A or the opening degree θ of the throttle valve 125 is reduced.

[0158] Although the embodiment of the control device for the internal combustion engine according to the present disclosure has been described in detail using the drawings, the specific structure is not limited to the embodiment, and design changes and the like within the scope not departing from the gist of the present disclosure are also included in the present disclosure.

[0159] Description of symbols

[0160] 110 Control device for internal combustion engine

[0161] 125 Throttle valve

[0162] A Opening area

[0163] Ac Corrected opening area

[0164] Av Correction value for opening area

[0165] Dpt threshold

[0166] EA Effective opening area

[0167] F2 Mass Flux Calculation Unit

[0168] F3 Opening area calculation section

[0169] F4 Effective opening area calculation section

[0170] F41 Pressure difference calculation unit

[0171] F42 Correction coefficient calculation unit

[0172] F43 Calibration Department

[0173] F5 Gas flow calculation unit

[0174] GF Gas flow

[0175] MF Mass Flux

[0176] Pd Downstream gas pressure (estimated value)

[0177] Pds Detected value of gas pressure on the downstream side

[0178] Pu upstream gas pressure measurement

[0179] Tu Upstream gas temperature

[0180] △P Differential pressure

[0181] μ correction factor

[0182] θ Opening

[0183] θc Opening after correction

[0184] θv Correction value for the opening.

Claims

1. A control device for an internal combustion engine, characterized in that: have: a mass flux calculation unit that calculates a mass flux of gas passing through the throttle valve based on an upstream gas temperature, an upstream gas pressure, and a downstream gas pressure of the throttle valve; an opening area calculation unit that calculates an opening area of ​​the throttle valve based on an opening degree of the throttle valve; an effective opening area calculation unit that calculates an effective opening area of ​​the throttle valve based on the upstream gas pressure, the downstream gas pressure, the opening degree, and the opening area; as well as a passing gas flow rate calculation unit that calculates a gas flow rate passing through the throttle valve based on the mass flux and the effective opening area, The effective opening area calculation unit comprises: a pressure difference calculation unit that calculates a pressure difference between the upstream gas pressure and the downstream gas pressure; a correction coefficient calculation unit that takes the pressure difference and the opening degree as inputs and calculates the correction coefficient based on a function of the following mathematical formula that specifies a relationship between the pressure difference and the correction coefficient, the correction coefficient being used to correct the opening area to the effective opening area; and a correction unit, the correction unit multiplies the opening area by the correction coefficient to obtain the effective opening area, μ = a i ·ΔP+b i , Wherein, μ represents the correction coefficient, and ΔP represents the pressure difference ΔP before and after the throttle valve.

2. The control device for an internal combustion engine according to claim 1, characterized in that: The correction coefficient calculation unit calculates the correction coefficient based on a relationship between the pressure difference set according to the opening degree and the correction coefficient.

3. The control device for an internal combustion engine according to claim 2, characterized in that: The relationship between the pressure difference and the correction coefficient is a proportional relationship having a positive correlation.

4. The control device for an internal combustion engine according to claim 3, characterized in that: The ratio of the change in the correction coefficient to the change in the pressure difference has a positive correlation with the opening degree.

5. The control device for an internal combustion engine according to claim 1, wherein: At least one of a correction value of the opening area and a correction value of the opening degree is learned based on the estimated value and the detected value of the downstream side gas pressure.

6. The control device for an internal combustion engine according to claim 5, characterized in that: The learning is performed when the difference between the estimated value and the detected value is equal to or greater than a threshold value.

7. The control device for an internal combustion engine according to claim 5, characterized in that: The effective opening area is calculated using at least one of the corrected opening area obtained by subtracting the correction value of the opening area from the opening area and the corrected opening degree obtained by subtracting the correction value of the opening degree from the opening degree.

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