JP6512078B2 - Injection control device and injection control system - Google Patents

Description

  The present invention relates to an injection control device in an internal combustion engine.

  2. Description of the Related Art Conventionally, there has been a demand for accurately measuring or estimating the flow rate of air passing through a throttle valve provided in an intake passage of an internal combustion engine. In Patent Document 1, in order to reduce the influence of the change in viscosity of air with respect to temperature on the measurement results, the air passing through the throttle valve is calculated based on a model equation including a viscosity correction coefficient. A flow rate estimator is disclosed.

JP, 2011-144682, A

  By the way, the characteristics of the intake flow rate sensor for detecting the intake flow rate passing through the throttle valve differ depending on the shape of the intake passage for each internal combustion engine. Heretofore, as for the characteristics of the intake flow rate sensor, the input / output characteristics have been measured and managed for each vehicle type, and hence for each shape of the intake passage.

  Conversely speaking, for internal combustion engine manufacturers and vehicle manufacturers, the variation of the shape of the intake passage for each vehicle type is grasped, the intake flow rate is measured for all the variations in advance, and the characteristic data of the intake flow rate sensor is accumulated. It must be done.

  Furthermore, in the case where an internal combustion engine not including the intake passage is sold alone, it is practically impossible to grasp in advance the intake flow rate sensor characteristic adapted to the shape of the intake passage. For example, since the control of fuel injection is performed based on the intake flow rate, if the accuracy of measurement or estimation of the intake flow rate is low, accurate injection control may be difficult.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection control device and an injection control system capable of estimating an intake flow rate more accurately for each intake passage.

  The invention disclosed herein employs the following technical means to achieve the above object. In addition, the reference numerals in the parenthesis described in the claims and this section indicate the correspondence with specific means described in the embodiment described later as one aspect, and the technical scope of the invention is limited. It is not something to do.

  In order to achieve the above object, the present invention is an injection control device including a control unit (100) for controlling the injection of fuel in an internal combustion engine, and an injection control system including the injection control device, the control unit comprising An actual measurement flow rate acquiring unit (111) for acquiring an actual measurement flow rate which is an actual measurement value of an intake air flow rate in an intake passage (400) for introducing air into a cylinder in which a piston (200) connected to a crankshaft (230) is accommodated; And a temperature acquisition unit (121) for acquiring the temperature in the intake passage, and a pressure acquisition unit (131) for acquiring the pressure in the intake passage, and the control unit controls the temperature in the intake passage and the intake passage. The theoretical flow rate calculated according to a predetermined theoretical formula based on the internal pressure and the volume of air taken into the cylinder until the piston reaches While sampling, it is characterized by calculating a regression characteristic line showing a regression relation between the actual measurement flow and the theoretical flow, and controlling the fuel injection on the regression characteristic line based on the estimated flow corresponding to the actual measurement flow. .

  According to this, if the control unit holds the volume (constant) of the air introduced into the cylinder as information, it obtains the temperature and pressure at any time after the intake passage is assembled in the cylinder. Theoretical intake flow can be calculated. In addition, it is possible to perform regression analysis with the calculated theoretical flow rate by acquiring the measured value of the intake flow rate. That is, the control unit can calculate a regression characteristic line indicating a regression relationship between the actual measurement flow rate and the theoretical flow rate, and derive the estimated flow rate used for the injection control based on the regression characteristic.

  Since the regression characteristic to be calculated is unique to the system of the internal combustion engine in which the cylinder and the intake passage are built up, it is not necessary to previously store the characteristic data of the intake flow rate sensor in consideration of the shape of the intake passage etc. . Further, since the regression characteristic is calculated based on the actual measurement flow rate for each system, it includes an error factor such as manufacturing variation of the intake passage. Therefore, the estimation accuracy of the inspiratory flow rate in each system can be improved as compared with the case of individually developing one characteristic data measured in advance.

It is a figure showing a schematic structure of an injection control system concerning a 1st embodiment. It is a block diagram which shows the detailed structure of a control part. It is a figure which shows the calculation method of a regression characteristic line. It is a figure explaining calculating an presumed flow from a regression characteristic line. It is a flowchart which shows the operation | movement flow of a control part. It is a flowchart which shows the operation | movement flow of the control part which concerns on a modification. It is a figure which shows the concept of determination of precision.

  Hereinafter, embodiments of the present invention will be described based on the drawings. The same reference numerals are given to parts which are the same as or equivalent to each other in the following drawings.

First Embodiment
First, with reference to FIG. 1, a schematic configuration of an injection control system including the injection control device and the injection control device according to the present embodiment will be described.

  The injection control system in the present embodiment is, for example, a system including an injection control device that controls injection by an injector in an internal combustion engine mounted on a vehicle. The vehicle may be a diesel vehicle or a gasoline vehicle, but in the present embodiment, a diesel vehicle without an igniter to be used for ignition of a mixture is described.

  As shown in FIG. 1, the injection control system 1000 in this embodiment is integrated with a piston 200, a cylinder 210 accommodating the piston 200, a crankshaft 230 connected to the piston 200 via a connecting rod 220, and the cylinder 210. And a crankcase 240 for accommodating the crankshaft 230. Note that an oil case for storing engine oil is not shown.

  Furthermore, the injection control system 1000 includes an injector 300 for injecting fuel into the cylinder 210.

  Further, the injection control system 1000 includes an intake passage 400 for introducing air into the cylinder 210 and an exhaust passage 500 for exhausting the gas after combustion from the inside of the cylinder 210.

  An intake valve 410 is provided at a connection end of the intake passage 400 with the cylinder 210. When the intake valve 410 is opened, the cylinder 210 and the intake passage 400 communicate with each other, and air flowing through the intake passage 400 can be introduced into the cylinder 210. Further, a throttle valve 420 is provided in the intake passage 400. The throttle valve 420 can change the opening degree arbitrarily. As the throttle valve 420 opens, the mass flow rate of air taken into the cylinder 210 increases. When the vehicle is traveling, throttle valve 420 is almost fully open. When exhaust gas is recirculated to the intake passage 400 by exhaust gas recirculation (EGR) described later, the throttle valve 420 is shifted to the valve closing side to reduce the amount of air introduced from the outside into the cylinder 210. Thus, an appropriate amount of air can be introduced into the cylinder 210.

  On the other hand, an exhaust valve 510 is provided at a connection end of the exhaust passage 500 with the cylinder 210. When the exhaust valve 510 is opened, the cylinder 210 and the exhaust passage 500 communicate with each other, and the gas in the cylinder 210 flows through the exhaust passage 500 and is exhausted to the outside.

  The injection control system 1000 in the present embodiment includes a recirculation passage 600 that communicates the exhaust passage 500 and the intake passage 400 without using the cylinder 210. The recirculation passage 600 is a passage for recirculating the exhaust gas to the intake air. The recirculation passage 600 is provided for so-called exhaust gas recirculation (EGR). The amount of generated NOx can be reduced by recirculating to the intake passage 400 a gas having a lower oxygen concentration than the air taken in by the combustion of the mixture present in the exhaust passage 500.

  A cooling unit 610 and a recirculation valve 620 are provided between the exhaust passage 500 and the intake passage 400. The cooling unit 610 cools the exhaust gas. The temperature of the mixture before ignition can be lowered by the cooling unit 610 as compared with the case of refluxing without cooling the exhaust gas. Thereby, the combustion temperature can be lowered to suppress the generation of NOx. The recirculation valve 620 regulates the flow rate of the exhaust gas returned from the exhaust passage 500 to the intake passage 400. Recirculation can be stopped by closing the recirculation valve 620 completely.

  Furthermore, the injection control system 1000 includes a control unit 100. The control unit 100 corresponds to a so-called engine ECU, and controls the injection of fuel by the injector 300. The control unit 100 also controls the opening degree of the intake valve 410, the exhaust valve 510, the throttle valve 420 and the recirculation valve 620. The control unit 100 will be described in detail later.

  The principle of rotation of the crankshaft 230 in the injection control system 1000 will be briefly described.

  The piston 200 reciprocates the inside of the cylinder 210 along the longitudinal direction of the cylinder 210. The piston 200 is mechanically connected to the crankshaft 230 via a connecting rod 220. Crankshaft 230 rotates as piston 200 reciprocates between top dead center and bottom dead center.

  The reciprocating motion of the piston 200 is realized by the expansion of the gas in the region R surrounded by the inner wall of the cylinder 210 and the piston 200 and the rotation due to the inertia of the crankshaft 240. Specifically, in an internal combustion engine driven by four strokes, intake valve 410 is opened from the top dead center where the volume of region R is the smallest to the bottom dead center where the volume of region R is the largest. Air of volume V is introduced into the cylinder 210. Thereafter, the air is compressed before the piston 200 reaches top dead center again. Then, after the temperature of air reaches a temperature corresponding to the ignition point of the mixture due to the temperature rise due to compression, a predetermined amount of fuel is injected from the injector 300 into the cylinder 210 at a predetermined timing to form an air-fuel mixture. The fuel-air mixture is ignited by the fuel injection. The ignition expands the combustion gas to energize the piston 200, and the piston 200 moves from the top dead center to the bottom dead center. Crankshaft 230 continues to rotate by inertia, but exhaust valve 510 is opened during a period from the bottom dead center to the top dead center of piston 200 to exhaust the combustion gas in cylinder 210 to exhaust passage 500. After the exhaust, the intake valve 410 is opened, and the intake is performed again while the piston 200 reaches from the top dead center to the bottom dead center. This cycle is repeated and the rotation of the crankshaft 230 continues.

  Next, the control unit 100 will be described in detail with reference to FIGS. 1 and 2.

  As shown in FIG. 2, the control unit 100 is communicably connected to the injector 300, and performs control to inject a predetermined amount of combustion into the cylinder 210 at a predetermined timing. This control is mainly performed based on an intake flow rate, which is a flow rate of air flowing through the intake passage 400, and a temperature T and a pressure P in the intake passage 400. Further, the control unit 100 controls the opening degree of the intake valve 410, the exhaust valve 510, the recirculation valve 620, and the throttle valve 420.

  As shown in FIG. 1, the injection control system 1000 includes a flow sensor 110, a temperature sensor 120, and a pressure sensor 130 in the intake passage 400. The flow rate sensor 110, the temperature sensor 120, and the pressure sensor 130 respectively correspond to a flow rate detecting unit, a temperature detecting unit, and a pressure detecting unit in the claims.

  As shown in FIG. 2, the control unit 100 has a measured flow rate acquiring unit 111, and a measured value (measured flow rate Ma) of the intake flow detected by the flow sensor 110 or a physical quantity (for example, one-to-one with the intake flow) The voltage or frequency output by the flow rate sensor 110 is acquired. Further, the control unit 100 has a temperature acquisition unit 121, and acquires an actual measurement value T of the temperature in the intake passage 400 detected by the temperature sensor 120. Further, the control unit 100 has a pressure acquisition unit 131, and acquires an actual measurement value P of the pressure in the intake passage 400 detected by the pressure sensor 130.

  In addition, the control unit 100 includes an arithmetic unit 101. The calculation unit 101 integrates the actual measurement flow rate Ma, the temperature T, and the pressure P acquired by the actual measurement flow rate acquisition unit 111, the temperature acquisition unit 121, and the pressure acquisition unit 131, respectively, and calibrates the characteristics of the flow sensor 110 with respect to the system. The regression characteristic line is calculated. The calculated regression characteristic line is stored in a memory 140 provided outside or inside the control unit 100, and is used to estimate an intake flow rate during traveling.

  Next, with reference to FIG. 3 and FIG. 4, a concrete concept of the calculation unit 101 calculating a regression characteristic line will be described.

In the injection control system 1000 in which the exhaust gas recirculation (EGR) in the present embodiment is performed, the mass flow rate M _{MAF of the} air flowing through the intake passage 400 is expressed as shown in Formula 1.

Here, M _CLD is a mass flow rate of gas flowing into the cylinder 210, M _EGR is a mass flow rate of gas recirculated from the recirculation passage 600 to the intake passage 400, and V is a top dead center and a bottom dead center of the piston 200 , P is the pressure in the intake passage 400, and T is the temperature in the intake passage 400. Here, R is a gas constant, and m _air is the apparent molecular weight of air (approximately 28.966 g / mol). V is a constant unique to the cylinder 210 of the internal combustion engine in the vehicle on which the control unit 100 is mounted, and is information to be stored in advance in the memory 140 or the like.

In the state where the recirculation valve 620 is closed, when the inside of the intake passage 400 reaches a steady state, it can be approximated as M _EGR = 0 and dP = 0, so Equation 1 becomes Equation 2.

The mass flow rate M _CLD of the gas flowing into the cylinder 210 can be approximated as Equation 3 using the equation of state of the gas.

Hereinafter, the intake flow rate of the intake passage 400 calculated by Equation 3 will be referred to as a theoretical flow rate Mb. As apparent from the equation 3, the theoretical flow rate Mb is the actual value T of the temperature in the intake passage 400 detected by the temperature sensor 120, the actual value P of the pressure in the intake passage 400 detected by the pressure sensor 130, and Of the intrinsic volume V, the gas constant R, and the apparent molecular weight m _{air of air} .

In Equation 3, the equation of state of an ideal gas is used to approximate the mass flow rate _MCLD , but the equation of state of a real gas may be used. For example, Van der Waal's equation of state, Deterici equation of state, Penn-Robinson equation of state, or virial equation may be adopted. These equations of state correspond to theoretical formulas described in the claims.

  The actually measured flow rate acquiring unit 111 in the control unit 100 acquires the actually measured flow rate Ma by setting the engine speed, that is, the combustion injection amount, and the opening degree of the throttle valve 420 in a predetermined state. The actual measurement flow rate Ma may be the flow rate itself, or may be an output value (for example, voltage or frequency) of the flow rate sensor 110 corresponding to the mass flow rate.

  In addition, the calculation unit 101 in the control unit 100 calculates the theoretical flow rate Mb based on the acquired temperature T and pressure P in the same state as the state in which the actual measurement flow rate Ma is acquired. Then, the calculation unit 101 records the measured flow rate Ma and the corresponding theoretical flow rate Mb in the memory 140.

  After acquisition of one measurement point (combination of measured flow rate Ma and theoretical flow rate Mb) is completed, the control unit 100 changes the intake air flow rate by changing the engine speed and the opening degree of the throttle valve 420 to perform the next measurement Get points. Thus, the control unit 100 measures a plurality of measurement points. As shown in FIG. 3, the computing unit 101 performs regression analysis with the actually measured flow rate Ma as an explanatory variable and the theoretical flow rate Mb as an objective variable to calculate a regression characteristic line.

  In a compressor turbine installed in the intake passage 400 and rotating in conjunction with an exhaust turbine (not shown) installed in the exhaust passage 500, the intake flow rate can be changed by arbitrarily changing the blade inclination angle There is. However, in such a case, it is preferable to keep the blade inclination angle constant at the time of acquiring measurement points for calculating the regression characteristic line.

  The regression characteristic line calculated by regression analysis may be nonlinear regression as well as linear regression using a linear equation. Further, the regression characteristic line shown in the present embodiment includes one that does not regress to a predetermined function, like a moving average line. When performing regression analysis by linear regression, at least two measurement points may be acquired.

  After calculating the regression characteristic line, the control unit 100 stores the calculated regression characteristic line in the memory 140. As shown in FIG. 4, the control unit 100 converts the measured flow rate detected by the flow rate sensor 110 into a theoretical flow rate based on the regression characteristic line, and uses the flow rate as the estimated flow rate to perform combustion injection control by the injector 300, It is used to control the opening degree of the intake valve 410, the exhaust valve 510, the recirculation valve 620, and the throttle valve 420.

  Although the form in which the regression characteristic line is stored in the memory 140 is not limited, for example, the regression characteristic line is stored as a function with the measured flow rate as an explanatory variable. In this case, the control unit 100 substitutes the measured flow rate detected by the flow rate sensor 110 into an explanatory variable to calculate the estimated flow rate.

  Also, a plurality of points on the regression characteristic line, that is, a combination of the measured flow rate Ma and the theoretical flow rate Mb on the regression characteristic line may be stored as a table in the memory 140. When an explanatory variable (measured flow rate) not in the table is observed by the flow rate sensor 110, the estimated flow rate is calculated by linear approximation between points existing in the table.

  Next, the operation flow of the control unit 100 will be described with reference to FIG.

  As shown in FIG. 5, first, step S1 is executed. Step S1 is a step in which the control unit 100 receives a calculation instruction of a regression characteristic line. The regression characteristic line is a correction factor for calibrating the measured flow rate to the theoretical flow rate in the system in which the flow rate sensor 110 is mounted. For this reason, although the timing which calculates a regression characteristic line is arbitrary, it is rare that calibration is performed by the general end user. The calculation command of the regression characteristic line is usually input to the control unit 100 by a maintenance factory or dealer. The control unit 100 starts calibration of the flow rate sensor 110 using this command as a trigger.

  After step S1, step S2 is executed. Step S2 is a step in which the control unit 100 determines whether the vehicle is in a state suitable for calibration of the flow rate sensor 110. The state suitable for calibration is, for example, a state in which the driver does not operate the accelerator, a state in which a load fluctuation can not occur due to gear-in, and a state in which failures of various sensors do not occur. These operations and failures are disturbances to the measurement of the measured flow rate and the calculation of the theoretical flow rate. Step S2 determines whether the vehicle condition is in an environment in which immobility of the intake flow can be secured while sampling one combination of the measured flow and the theoretical flow, ie, an environment suitable for calibration. Step to If the vehicle is in an environment suitable for calibration, step S2 is a YES determination.

  Further, the calibration in the present embodiment can be realized by intentionally changing the intake flow rate and sampling the measured flow rate Ma and the theoretical flow rate Mb. That is, in order to change the intake flow rate, the engine speed and the opening degree of the throttle valve 420 are changed. In particular, under conditions where the intake flow rate is relatively large, the load on the internal combustion engine may be greater than that during normal driving. For this reason, in step S2, in addition to determining the above-mentioned disturbance-free state, it is determined whether the vehicle is in a safe state in which a situation such as sudden start without intention occurs. You may do so. For example, if the shift range is neutral and the other actuators are in a disabled state with respect to changes in the engine speed and the opening degree of the throttle valve 420, the determination is YES. If the determination in step S2 is NO, the operation flow relating to the calibration ends.

  When step S2 is a YES determination, it progresses to step S3. Step S3 is a step in which the control unit 100 closes the recirculation valve 620 and sets the engine speed and thus the amount of combustion injection by the injector 300 and the opening degree of the throttle valve 420 in a predetermined state. By this step S3, the intake flow rate of the air flowing through the intake passage 400 becomes the flow rate corresponding to the set state.

  After step S3, step S4 is executed. In step S4, the variation with respect to time of the actually measured flow rate Ma acquired by the actually measured flow rate acquiring unit 111, the temperature T acquired by the temperature acquiring unit 121, and the pressure P acquired by the pressure acquiring unit 131 falls within a predetermined range. It is a step to determine whether or not there is. If the variation of the actual measurement values is within the predetermined range, the control unit 100 determines that the state in the intake passage 400 has sufficiently reached the steady state. That is, step S4 is a YES determination. In the case of NO determination, the state set in step S3 is maintained until YES determination is made.

  When step S4 is a YES determination, it progresses to step S5. Step S5 is a step in which the measured flow rate acquiring unit 111 in the control unit 100 acquires the measured flow rate Ma and calculates the theoretical flow rate Mb based on Formula 3.

  After step S5, step S6 is performed. Step S6 is a step in which the control unit 100 determines whether or not a sufficient number of measurement points for regression analysis, ie, a combination of the measured flow rate Ma and the theoretical flow rate Mb, can be obtained. As described above, in the case of linear regression, at least two measurement points may be obtained. However, it is preferable to obtain as many measurement points as possible uniformly from a low flow rate area where the actual measurement flow rate Ma is relatively small to a large flow rate area where the flow rate is relatively large, regardless of linear regression or nonlinear regression. Needless to say.

  If it is determined in step S6 that a sufficient number of measurement points have not been acquired, the determination is NO, and the process returns to step S3. In such a case, the intake air flow rate is changed by changing the engine speed, that is, the combustion injection amount by the injector 300 and the opening degree of the throttle valve 420 with respect to the intake flow rate acquisition state set previously. . In the low flow rate region, the intake air flow rate is adjusted only by adjusting the opening degree of the throttle valve 420 while the engine speed is relatively small. In the middle flow rate region and the large flow rate region, the throttle valve 420 may be fully opened, and the intake flow rate may be adjusted by the engine speed.

  In step S6, it is determined that a sufficient number of measurement points have been acquired, and when step S6 is determined as YES, the process proceeds to step S7. Step S7 is a step in which the control unit 100 executes regression analysis to calculate a regression characteristic line. The specific concept of the calculation of the regression characteristic line is as described above, and thus the detailed description is omitted.

  After step S7, the process proceeds to step S8. Step S8 is a step in which the control unit 100 stores the calculated regression characteristic line in the memory 140. The storage of the regression characteristic line is also as described above, and thus the detailed description is omitted.

  Thereby, the control unit 100 converts the measured flow rate Ma detected by the flow rate sensor 110 into an estimated flow rate based on the regression characteristic line during traveling or the like, and controls the combustion injection by the injector 300 based on the estimated flow rate. Alternatively, the opening degree of the intake valve 410, the exhaust valve 510, the recirculation valve 620, and the throttle valve 420 can be controlled.

  Next, the effects and advantages of employing the injection control system and the injection control system including the injection control system in the present embodiment will be described.

  If control unit 100 holds volume V (constant) of air introduced into cylinder 210 as information, temperature T, pressure P, etc. at any time after intake passage 400 is assembled in cylinder 210. The theoretical intake flow rate (theoretical flow rate Mb) can be calculated by obtaining. In addition, it is possible to perform regression analysis with the calculated theoretical flow rate by acquiring the measured value of the intake flow rate (measured flow rate Ma). That is, the control unit 100 can calculate a regression characteristic line indicating a regression relationship between the actual measurement flow and the theoretical flow, and derive an estimated flow to be provided for the injection control based on the regression characteristic line and the actual measurement flow.

  Since the regression characteristic line to be calculated is unique to the system of the internal combustion engine in which the cylinder 210 and the intake passage 400 are assembled, the characteristic data of the flow rate sensor is accumulated in advance in consideration of the shape of the intake passage 400 and the like. There is no need to leave. Further, since the regression characteristic line is calculated based on the measured flow rate for each system, it includes an error factor such as manufacturing variation of the intake passage 400. Therefore, the estimation accuracy of the inspiratory flow rate in each system can be improved as compared with the case of individually developing one characteristic data measured in advance.

(Modification)
As to the measured flow rate Ma acquired in step S5 and the calculated theoretical flow rate Mb, the accuracy and the accuracy are determined to determine whether the measurement point should be used to calculate the regression characteristic line or not. Also good.

  Further, the accuracy or the accuracy of the regression characteristic line calculated in step S7 may be determined to determine whether the regression characteristic line is used to calculate the estimated flow rate.

  What incorporated these determinations into the operation flow of the control unit 100 is shown in FIG. Specifically, step S9 intervenes after step S5 in the operation flow described in the first embodiment. Moreover, step S10 intervenes after step S7.

  Step S9 is a step in which the control unit 100 determines whether or not the measurement points of the measured flow rate Ma and the theoretical flow rate Mb acquired or calculated at the time of step S5 are likely to be. For example, as shown in FIG. 7, the upper limit value and the lower limit value of the theoretical flow rate assumed in advance are set for a certain measured flow rate Ma. In FIG. 7, upper limit lines are illustrated as a set of upper limit values over the entire measured flow rate Ma. Similarly, the lower limit line is illustrated as a set of lower limits over the entire measured flow rate Ma.

  When the measurement point obtained in step S5 is present in the area below the upper limit line and above the lower limit value, the control unit 100 determines that step S9 is YES and proceeds to step S6. On the other hand, if the measurement point deviates from the region below the upper limit line and below the lower limit value, step S9 is determined as NO. When step S9 is NO determination, it returns to step S3. In step S3 in this case, the intake flow rate acquisition state may be the same as the condition before the step returns, or the condition may be changed.

  As described above, determining whether the measurement point is between the upper limit line and the lower limit line corresponds to determining the accuracy of the measurement point. Besides the determination of the accuracy, the accuracy of the measurement point may be determined. Specifically, in step S5, a plurality of measurements are performed under the same intake flow rate acquisition state. Then, step S9 may be determined as YES when the standard deviation concerning the plurality of measurement points is equal to or less than a predetermined threshold value.

  On the other hand, step S10 is a step in which the control unit 100 determines whether the regression characteristic line calculated at the time of step S7 is likely to be.

  Similar to the determination of the accuracy in step S6, the upper limit line and the lower limit line are previously defined, and the step is performed if the regression characteristic line obtained in step S7 is in the region below the upper limit line and above the lower limit. It is determined that S10 is a YES determination, and the process proceeds to step S8. On the other hand, if the regression characteristic line deviates from the region below the upper limit line and above the lower limit value, step S10 is determined as NO. If the determination in step S10 is NO, the control unit 100 ends the operation flow. Alternatively, the process may return to step S3 to repeat the measurement again.

  As described above, determining whether or not the regression characteristic line exists between the upper limit line and the lower limit line corresponds to determining the accuracy of the regression characteristic line. Besides the determination of the accuracy, the accuracy of the regression characteristic line may be determined. Specifically, step S10 may be determined as YES when the determination coefficient related to the regression characteristic line subjected to the regression analysis in step S7 is equal to or more than a predetermined threshold value. For example, when the determination coefficient of the regression characteristic line is 0.8 or more, YES determination is made in step S10.

  Although step S9 and step S10 for performing determination of accuracy or precision are not necessarily essential for calculation of the regression characteristic line, at least one of the steps is executed to guarantee the certainty of the regression characteristic line it can. That is, the estimated flow rate can be calculated with higher accuracy and higher accuracy.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments and can be variously modified and implemented without departing from the spirit of the present invention.

  In the above-described embodiment and modification, the injection control system in a diesel vehicle has been described. However, even in the case of a gasoline vehicle having an igniter, the regression characteristic line can be similarly calculated. In other words, the operation flow of the control unit 100 can be performed without distinction between diesel vehicles and gasoline vehicles. Needless to say, the exhaust gas recirculation (EGR) mechanism is not essential.

  Moreover, although the case where a regression characteristic line is calculated paying attention to one cylinder was described in the above-mentioned embodiment and modification, a regression characteristic line can be similarly calculated also in the case of many cylinders. In the internal combustion engine including a plurality of cylinders 210, when the flow rate sensor 110 is installed in the intake passage 400 connected to each cylinder 210, calibration is performed for each flow rate sensor, and the number of flow rate sensors 110 The regression characteristic line is calculated by the number of cylinders). On the other hand, when only one flow rate sensor 110 is installed on the upstream side before the intake passage 400 branches toward each cylinder 210, calibration is performed on the one flow rate sensor 110, One regression characteristic line will be calculated.

  In the embodiment and the modification described above, an example in which the corresponding physical quantity is directly detected by the flow sensor 110, the temperature sensor 120, and the pressure sensor 130 as the flow detection unit, the temperature detection unit, and the pressure detection unit is described. However, it may be detected indirectly, such as calculated from other characteristic values.

100: Control unit, 200: Piston, 210: Cylinder, 300: Injector, 400: Intake passage, 420: Throttle valve, 500: Exhaust passage, 600: Recirculation passage

Claims (5)

An injection control apparatus comprising a control unit (100) for controlling fuel injection in an internal combustion engine, comprising:
The control unit
An actual measurement flow rate acquiring unit (111) for acquiring an actual measurement flow rate, which is an actual measurement value of an intake air flow rate in an intake passage for introducing air into a cylinder (210) in which air is introduced into a cylinder (210) ,
A temperature acquisition unit (121) for acquiring the temperature in the intake passage;
And a pressure acquisition unit (131) for acquiring the pressure in the intake passage.
The control unit
Said measured flow rate,
Calculated according to a predetermined theoretical formula based on the temperature in the intake passage, the pressure in the intake passage, and the volume of air taken into the cylinder before the piston reaches the bottom dead center. Sampling the theoretical flow rate while changing the intake flow rate;
Calculating a regression characteristic line indicating a regression relationship between the measured flow rate and the theoretical flow rate;
An injection control device that controls fuel injection based on an estimated flow rate corresponding to the measured flow rate on the regression characteristic line. The control unit
The actual measured flow rate and the theoretical flow rate are sampled by changing the intake flow rate by changing at least one of the opening degree of the throttle valve (420) installed in the intake passage and the rotational speed of the internal combustion engine The injection control device according to Item 1.   The said control part performs calculation of the said regression characteristic line under predetermined conditions which can ensure immobility of the said inspiratory flow while sampling one combination of the said actual measurement flow and the said theoretical flow. An injection control device according to item 2.   The controller according to any one of claims 1 to 3, wherein the control unit determines the accuracy or precision of the calculated regression characteristic line, and calculates the estimated flow rate based on the regression characteristic line satisfying a predetermined condition. Injection control device. A cylinder (210) in which a piston (200) mechanically connected to a crankshaft (230) is accommodated;
An intake passage (400) for introducing air into the cylinder;
A flow rate detection unit (110) installed in the intake passage and detecting an intake flow rate in the intake passage;
A temperature detection unit (120) installed in the intake passage and detecting a temperature in the intake passage;
A pressure detection unit (130) installed in the intake passage for detecting the pressure in the intake passage;
A control unit (100) for controlling fuel injection;
The control unit
An actual measurement flow rate of the intake flow rate detected by the flow rate detection unit;
A predetermined theory based on the temperature detected by the temperature detection unit, the pressure detected by the pressure detection unit, and the volume of air taken into the cylinder until the piston reaches the bottom dead center. Sampling the theoretical flow rate calculated according to the equation while changing the intake flow rate;
Calculating a regression characteristic line indicating a regression relationship between the measured flow rate and the theoretical flow rate;
An injection control system that controls fuel injection based on an estimated flow rate corresponding to the measured flow rate on the regression characteristic line.

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