JP5994465B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device related to throttle valve opening control.

  An engine mounted on a vehicle in recent years is provided with an atmospheric pressure sensor that detects atmospheric pressure, an intake pressure sensor that detects the pressure of an intake manifold located downstream of the throttle valve as an intake pressure, and the like. The intake air pressure is a parameter related to the engine load, and the atmospheric pressure is a typical parameter representing the driving environment. Therefore, the pressure information detected by these pressure sensors is suitable for accurately controlling the output of the engine.

  On the other hand, if these pressure sensors fail or the output value becomes abnormal, the controllability of the engine is degraded. Therefore, various failure determination devices have been developed for appropriately determining failure and abnormality of these pressure sensors. For example, there is one that determines a failure of a pressure sensor based on a relationship between an engine operation mode and an output value of the pressure sensor (see Patent Document 1). In addition, a technique for performing failure determination based on a ratio or deviation between an estimated value and an actually measured value of the intake pipe pressure has been developed (see Patent Document 2).

JP 2005-113809 JP JP 2010-48125 A

  However, the prior art as described above merely determines the failure of the pressure sensors, and the controllability of the engine cannot be maintained when the failure actually occurs. That is, although it is possible to determine that the output of the pressure sensors is inappropriate, information that substitutes for the inappropriate output cannot be obtained. Therefore, it is difficult to avoid the possibility that the engine load and operating environment cannot be accurately grasped, and it is difficult to avoid deterioration of engine stall and drivability.

  On the other hand, it is also conceivable to construct an engine simulation model and to predict the pressure state of the intake system based on the parameters of actual control. However, it is considered that such a simulation model has a large computation scale and is difficult to implement in terms of cost in order to be calculated by an in-vehicle electronic control device. In addition, since the computation load is large, it is difficult to obtain simulation results in a short time, and there are many problems in application and application to real-time real-time control.

One of the purposes of the present invention was devised in view of the above problems, and provides an engine control device that can improve the reliability of control regardless of whether or not a pressure sensor has failed. It is to be.
The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described below, and it is also positioned as another object of the present case to exhibit a function and effect that cannot be obtained by the conventional technology. be able to.

(1) The engine control device disclosed herein includes an actual measurement value detecting means for detecting an actual measurement value of at least one of the upstream pressure and the downstream pressure in the throttle valve portion of the engine, and a maximum torque equivalent value of the engine . Pressure ratio equivalent value calculating means for calculating a ratio of a target torque equivalent value, which is a torque required for the engine , as a pressure ratio equivalent value. Further, based on the actual measurement value detected by the actual measurement value detection means and the pressure ratio equivalent value calculated by the pressure ratio equivalent value calculation means, at least one of the virtual values of the upstream pressure and the downstream pressure is calculated. Virtual value calculating means for calculating is provided.

The pressure ratio equivalent value is a value corresponding to the ratio (pressure ratio) of the downstream pressure to the upstream pressure of the throttle valve. In addition, regarding the detection target of the actual measurement value by the actual measurement value detecting means, either one is referred to as “one”, and the other one is referred to as “the other”.
For example, when the actually measured value is the upstream pressure, a virtual value of the downstream pressure is calculated using this and the pressure ratio equivalent value. Further, when the actually measured value is the downstream pressure, the virtual value of the upstream pressure is calculated using the value and the pressure ratio equivalent value. Note that when the actual measurement values are both the upstream pressure and the downstream pressure, virtual values for the upstream pressure and the downstream pressure can be calculated.

(2) In addition, the measured value detection means detects the measured values of both the upstream pressure and the downstream pressure,
It is preferable to include a control unit that controls the engine based on the virtual value calculated by the virtual value calculation unit when the measured value detection unit fails.
For example, when the actual value detection means for detecting the actual value of the upstream pressure fails, a virtual value of the upstream pressure is calculated based on the actual value of the downstream pressure, and this is used instead of the actual value of the upstream pressure. Preferably used to control the engine.

(3) Moreover, it is preferable to provide the determination means which determines the failure of the said actual value detection means by the comparison with the said actual value and the said virtual value.
For example, the virtual value calculation means calculates the virtual value of the upstream pressure based on the actual measurement value of the downstream pressure, and the determination means compares the actual measurement value of the upstream pressure and the virtual value of the upstream pressure. It is preferable. In this case, a failure related to the detection of the upstream pressure is determined in the actually measured value detecting means.

  (4) Further, the actual measurement value detection unit detects an actual measurement value of the atmospheric pressure as the upstream pressure, and the virtual value calculation unit calculates a virtual intake based on the pressure ratio equivalent value and the actual measurement value of the atmospheric pressure. It is preferable to calculate the manifold pressure.

(5) In addition, a flow rate detection unit that detects an intake flow rate of the engine may be provided, and the virtual value calculation unit may calculate the other virtual value based on the intake flow rate detected by the flow rate detection unit. preferable.
That is, it is preferable that the virtual value calculating means calculates the other virtual value based on the intake flow rate, the one actually measured value, and the pressure ratio equivalent value.

(6) Further, the pressure ratio equivalent value calculating means calculates the torque generated in the engine as the maximum torque equivalent value based on the amount of air introduced into the engine, and based on the accelerator operation amount of the engine. Preferably, the set target torque is calculated as the target torque equivalent value.
In this case, the pressure ratio equivalent value is calculated based on the magnitude of torque generated in the engine.

(7) Alternatively, the pressure ratio equivalent value calculation means uses the maximum charging efficiency of the engine as the maximum torque equivalent value and calculates the target torque equivalent value based on the amount of air introduced into the engine. It is preferable to calculate the pressure ratio equivalent value using the target filling efficiency.
In this case, the pressure ratio equivalent value is calculated based on the amount of air taken into the cylinder of the engine. The pressure ratio equivalent value may be calculated using the method described in (6) above.

  (8) Preferably, the pressure ratio equivalent value calculating means calculates the maximum torque equivalent value according to the maximum valve lift amount or valve timing of the intake / exhaust valve. That is, it is preferable to calculate the maximum engine torque that can be generated in the control state of the intake and exhaust valves at the time of calculation as the maximum torque equivalent value.

  (9) Further, it is preferable that the pressure ratio equivalent value calculating means calculates a torque generated in the engine when the ignition timing is an optimum ignition timing (that is, MBT) as the maximum torque equivalent value. When the ignition timing cannot be set to the optimum ignition timing from the viewpoint of preventing knocking, the torque generated when ignition is performed at a predetermined ignition timing slightly retarded from the optimum ignition timing is the maximum torque. You may calculate as an equivalent value.

  (10) Further, it is preferable that the pressure ratio equivalent value calculating means calculates a maximum torque generated in the engine at the time of combustion at a preset predetermined air-fuel ratio as the maximum torque equivalent value. Specific examples of the predetermined air-fuel ratio include a stoichiometric air-fuel ratio (for example, an air-fuel ratio of around 14.7) and an output air-fuel ratio (for example, an air-fuel ratio of 12.0 to 13.0).

In the disclosed engine control device, the virtual value is calculated based on the pressure ratio equivalent value and the actually measured value. Thereby, the theoretical magnitude of the intake system pressure can be grasped with a simple calculation configuration that does not require a complicated intake system model. Therefore, the reliability of control can be improved regardless of the presence or absence of a failure in the actual value detection means.
For example, it is possible to determine a failure of a sensor that detects an actual measurement value of the intake system pressure, and it is possible to use a virtual value as an alternative to the actual measurement value at the time of the failure. Alternatively, a sensor with low reliability can be omitted, and the controllability of the engine can be improved while simplifying the device configuration.

It is a figure which illustrates the block configuration of the control apparatus of the engine which concerns on one Embodiment, and the structure of the engine to which this control apparatus was applied. It is a block block diagram for demonstrating the calculation content in this control apparatus. It is a graph which illustrates the relationship between the actual filling efficiency, ignition timing, and torque which concern on this control apparatus. It is a graph which illustrates the relationship between the maximum torque and engine speed which are calculated with this control apparatus. It is a graph for demonstrating the correlation with the pressure ratio equivalent value which concerns on this control apparatus, and an actual pressure ratio, (a) uses the pressure ratio equivalent value calculated based on the illustrated mean effective pressure, b) uses the pressure ratio equivalent value calculated based on the charging efficiency. It is a graph which illustrates the relationship between the pressure loss of the upstream of the throttle valve calculated by this control apparatus, and an intake air flow rate. It is a graph for demonstrating an example of the failure determination method by this control apparatus.

  An engine control apparatus will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment, and can be selected or combined as necessary.

[1. Device configuration]
[1-1. engine]
The engine control device of the present embodiment is applied to the in-vehicle gasoline engine 10 shown in FIG. Here, one of a plurality of cylinders provided in the multi-cylinder engine 10 is shown. The piston 16 is provided so as to be slidable back and forth along the inner peripheral surface of a cylinder 19 formed in a hollow cylindrical shape. The space surrounded by the upper surface of the piston 16 and the inner peripheral surface and top surface of the cylinder 19 functions as a combustion chamber 26 of the engine. The lower portion of the piston 16 is connected to a crank arm having a central axis that is eccentric from the axis of the crankshaft 17 via a connecting rod. Thereby, the reciprocating motion of the piston 16 is transmitted to the crank arm and converted into the rotational motion of the crankshaft 17.

  An intake port 11 for supplying intake air into the combustion chamber 26 and an exhaust port 12 for discharging exhaust gas after combustion in the combustion chamber 26 are formed in the top surface of the cylinder 19. An intake valve 14 and an exhaust valve 15 are provided at the end of the intake port 11 and the exhaust port 12 on the combustion chamber 26 side. The operations of the intake valve 14 and the exhaust valve 15 are individually controlled by a variable valve mechanism 27 provided in the upper part of the engine 10. A spark plug 13 is provided at the top of the cylinder 19 with its tip projecting toward the combustion chamber 26. The ignition timing by the spark plug 13 is controlled by the engine control device 1 described later.

  The variable valve mechanism 27 is a mechanism that changes the maximum valve lift amount and the valve timing individually or in conjunction with each of the intake valve 14 and the exhaust valve 15. The variable valve mechanism 27 includes a VVL device 27a and a VVT device 27b as a mechanism for changing the rocking amount and rocking timing of the rocker arm.

The VVL device 27a is a mechanism that continuously changes the maximum valve lift amount of the intake valve 14 and the exhaust valve 15. The VVL device 27a has a function of changing the magnitude of the swing transmitted from the cam fixed to the camshaft to the rocker arm. A specific structure for changing the magnitude of the rocker arm swing is arbitrary.
The displacement angle from the reference position of the rocking member with respect to the rocker shaft is called a control angle θ _VVL . The control angle θ _VVL is a parameter corresponding to the maximum valve lift amount, and it is assumed that the reference position of the swing member is set so that the maximum valve lift amount increases as the control angle θ _VVL increases. The VVL device 27a controls the maximum valve lift to an arbitrary value by adjusting the control angle θ _VVL . Information on the control angle θ _VVL controlled by the VVL device 27 a is transmitted to the engine control device 1.

The VVT device 27b is a mechanism that changes the opening / closing timing (valve timing) of the intake valve 14 and the exhaust valve 15. The VVT device 27b has a function of changing the rotational phase of the cam or camshaft that causes the rocker arm to swing. By changing the rotational phase of the cam or the camshaft, the rocker arm swing timing with respect to the rotational phase of the crankshaft 17 can be continuously changed (shifted).
The amount of change in angle indicating how much the actual camshaft phase angle is advanced or retarded from the reference camshaft phase angle is referred to as phase angle _θVVT . The phase angle θ _VVT is a parameter corresponding to the valve timing. The VVT device 27b arbitrarily controls the valve timing by adjusting the phase angle θ _VVT . Information on the phase angle θ _VVT controlled by the VVT device 27 b is transmitted to the engine control device 1.

[1-2. Intake and exhaust system]
An injector 18 for injecting fuel is provided in the intake port 11. The amount of fuel injected from the injector 18 is controlled by the engine control device 1 described later. Further, an intake manifold 20 (hereinafter referred to as an intake manifold) is provided upstream of the injector 18 in the intake air flow. The intake manifold 20 is provided with a surge tank 21 for temporarily storing air flowing toward the intake port 11 side. The intake manifold 20 on the downstream side of the surge tank 21 is formed to branch toward the intake ports 11 of the plurality of cylinders 19, and the surge tank 21 is located at the branch point. The surge tank 21 functions to alleviate intake pulsation and intake interference that can occur in each cylinder.

A throttle body 22 is connected to the upstream side of the intake manifold 20. An electronically controlled throttle valve 23 is built in the throttle body 22, and the amount of air flowing to the intake manifold 20 is adjusted according to the opening (throttle opening) of the throttle valve 23. The throttle opening is controlled by the engine control device 1.
An intake passage 24 is connected further upstream of the throttle body 22, and an air filter 25 is interposed further upstream of the intake passage 24. Thus, fresh air filtered by the air filter 25 is supplied to each cylinder 19 of the engine 10 via the intake passage 24 and the intake manifold 20.

[1-3. Detection system]
The crankshaft 17 of the engine 10 is provided with an engine rotation speed sensor 31 that detects the rotation speed Ne. In addition, it is good also as a control structure which provides the sensor which detects the rotation angle of the crankshaft 17 instead of the rotation speed Ne, and calculates the rotation speed Ne of the engine 10 inside the engine control apparatus 1 based on this rotation angle.
An air flow sensor 32 that detects the intake air flow rate Q is provided on the intake passage 24 upstream of the throttle valve 23. An intake manifold pressure sensor 33 (intake manifold pressure sensor) for detecting the pressure in the surge tank 21 is provided downstream of the throttle valve 23. Hereinafter simply referred to as the intake manifold pressure P _IM to a pressure in the surge tank 21.

An atmospheric pressure sensor 34 is provided inside the engine control device 1 or at an arbitrary position of the vehicle. The atmospheric pressure sensor 34 detects atmospheric pressure (atmospheric pressure) _PBP . The atmospheric pressure P _BP corresponds to the pressure at the inlet of the intake passage 24 (pressure upstream of the air filter 25). In addition, an accelerator opening sensor 35 that detects the amount of depression of the accelerator pedal (accelerator opening A _PS ) is provided at an arbitrary position of the vehicle (for example, in the vicinity of the accelerator pedal). The accelerator opening A _PS is a parameter corresponding to the driver's acceleration request, that is, corresponds to an output request to the engine 10.

Intake manifold pressure P _IM detected by the intake manifold pressure sensor 33 corresponds to the downstream pressure of the throttle valve 23 parts. The atmospheric pressure P _BP detected by the atmospheric pressure sensor 34 macroscopically corresponds to the upstream pressure of the throttle valve 23 portion. However strictly speaking, a value obtained by subtracting the pressure loss that is lost in the intake passage 24 upstream of the throttle valve 23 (pressure loss) from the atmospheric pressure P _BP becomes the upstream pressure of the throttle valve 23 parts. In this embodiment, each of the intake manifold pressure sensor 33 and the atmospheric pressure sensor 34 functions as actual value detection means for detecting the downstream pressure and the upstream pressure in the throttle valve 23 part. Is a correction of the pressure loss to the atmospheric pressure P _BP detected by the atmospheric pressure sensor 34.

  A cooling water temperature sensor 36 for detecting the temperature of the engine cooling water (cooling water temperature WT) is provided at an arbitrary position on the water jacket or the cooling water circulation path. An oil temperature sensor 37 that detects the temperature of the engine oil (oil temperature OT) is provided at an arbitrary position on the oil pan of the engine 10 or the circulation path of the engine oil. These cooling water temperature WT and oil temperature OT are parameters used for grasping no-load loss (such as mechanical loss inherent in engine 10 itself).

Information about the rotational speed Ne, intake air flow rate Q, intake manifold pressure P _IM , atmospheric pressure P _BP , accelerator opening A _PS , cooling water temperature WT, and oil temperature OT acquired by the various sensors 31 to 37 is an engine control device. 1 is transmitted. The engine control apparatus 1 according to the present embodiment calculates virtual values corresponding to the measured downstream pressure and upstream pressure of the throttle valve 23 and controls the engine 10 based on the virtual values or sensors. Determine the failure.

[1-4. Control system]
A vehicle equipped with the engine 10 is provided with an engine control device 1 (Engine Electronic Control Unit). The engine control device 1 is configured as, for example, an LSI device or a built-in electronic device in which a microprocessor, ROM, RAM, and the like are integrated, and is connected to a communication line of an in-vehicle network provided in the vehicle.

On the in-vehicle network, various known electronic control devices such as a brake control device, a transmission control device, a vehicle stability control device, an air conditioning control device, and an electrical component control device are connected so as to communicate with each other. An electronic control device other than the engine control device 1 is called an external control system, and a device controlled by the external control system is called an external load device.
The engine control device 1 is an electronic control device that comprehensively controls a wide range of systems such as an ignition system, a fuel system, an intake / exhaust system, and a valve system related to the engine 10. The amount of air supplied to each cylinder 19 and fuel injection This controls the amount, ignition timing, maximum valve lift, valve timing, and the like.

  On the input side of the engine control device 1, as shown in FIG. 1, an engine rotation speed sensor 31, an air flow sensor 32, an intake manifold pressure sensor 33, an atmospheric pressure sensor 34, an accelerator opening sensor 35, a coolant temperature sensor 36, and an oil temperature A sensor 37 is connected. Further, an ignition plug 13, an injector 18, a throttle valve 23, a variable valve mechanism 27, and the like that are controlled objects are connected to the output side of the engine control device 1.

[2. Control device]
As shown in FIG. 1, the engine control device 1 is provided with a pressure ratio equivalent value calculation unit 2, a virtual value calculation unit 3, a determination unit 4, and a control unit 5. Each of these elements may be realized by an electronic circuit (hardware), may be programmed as software, or some of these functions are provided as hardware, and the other part is software. It may be a thing.

[2-1. Pressure ratio equivalent value calculation unit]
The pressure ratio equivalent value calculation unit 2 (pressure ratio equivalent value calculation means) calculates a pressure ratio equivalent value A that is a value corresponding to the pressure ratio C of the intake system of the engine 10. The pressure ratio C means the ratio of the downstream pressure to the actual upstream pressure of the throttle valve 23. On the other hand, the pressure ratio equivalent value A is a value having a strong correlation with the actual pressure ratio C, and is obtained from a value corresponding to the maximum torque of the engine 10 and a value corresponding to the target torque of the engine 10 at that time. Calculated. As shown in FIG. 2, the pressure ratio equivalent value calculation unit 2 includes a maximum torque calculation unit 2a, a target torque calculation unit 2b, and a ratio calculation unit 2c.

The maximum torque calculator 2a calculates a maximum torque Pi _MAX that can be generated in the engine 10 or an equivalent value based on the rotational speed Ne of the engine 10. In general, the magnitude of torque generated in the engine 10 varies according to the rotational speed Ne, the amount of air introduced into the cylinder, the fuel injection amount, the ignition timing, the maximum valve lift amount, the valve timing, and the like. The magnitude of torque generated at a predetermined air-fuel ratio when the rotational speed Ne of the engine 10 is a predetermined value (constant) is represented by a graph as shown in FIG. When the air amount is Q ₁ , the engine 10 outputs the maximum torque Pi ₁ when the ignition timing is T ₁ . When the fluctuation of the torque with respect to the ignition timing is indicated by a curve, the curve is convex upward. The maximum torque when the air amount is Q ₂ is Pi ₂ , and the ignition timing for outputting the torque is T ₂ .

Based on the relationship shown in FIG. 3, the maximum torque calculation unit 2a is configured to maximize the torque generated when the intake air amount is maximum in the operating state of the engine 10 at that time (the throttle opening is fully opened). Torque) is calculated as the maximum torque Pi _MAX . For example, as shown by the solid line in FIG. 4, the maximum torque Pi _MAX is calculated using a graph, a correspondence map, a mathematical expression, etc. that define the correspondence between the maximum torque Pi _MAX and the rotational speed Ne when the throttle is fully opened. Also good. The value of the maximum torque Pi _MAX calculated here is transmitted to the ratio calculation unit 2c.

Like ignition timings T ₁ and T ₂ shown in FIG. 3, the optimal ignition timing (MBT: Minimum spark advance for Best Torque) is the ignition timing that generates the maximum torque in the engine 10 to which a certain amount of air is introduced. Call it. The optimum ignition timing moves toward the retard side (retard side) as the amount of air introduced into the cylinder 19 increases, and moves toward the advance side (advance side) as the amount of air decreases. Further, the optimum ignition timing moves to the retard side as the rotational speed Ne decreases, and moves to the advance side as the rotational speed Ne increases.

In the calculation of the maximum torque Pi _{MAX in} the maximum torque calculation unit 2a, basically, the torque generated when ignition is performed at the optimal ignition timing is calculated as the maximum torque Pi _MAX . However, when the ignition timing cannot be set to the optimal ignition timing from the viewpoint of preventing knocking of the engine 10, the torque generated when the ignition is ignited at a predetermined ignition timing slightly behind the optimal ignition timing is set to the maximum torque Pi. Calculate as _MAX . Knocking is less likely to occur as the ignition timing is delayed, but engine torque decreases as the ignition timing is delayed. Therefore, it is preferable to set the predetermined ignition timing close to the advance angle close to the optimal ignition timing in the ignition timing range where almost no knock occurs.

When the ignition timing is changed, the correspondence relationship between the maximum torque Pi _MAX and the rotational speed Ne when the throttle is fully opened also changes, and the position and shape of the solid line graph in FIG. 4 change. On the other hand, as shown by a broken line in FIG. 4, the maximum torque Pi _MAX corresponding to the ignition timing can be calculated by setting a graph corresponding to a plurality of ignition timings in advance. Therefore, the maximum torque calculator 2a may be configured to calculate the maximum torque Pi _MAX according to the rotational speed Ne and the ignition timing.

Regarding the air-fuel ratio, it is preferable to calculate the maximum torque Pi _MAX on the assumption that the air-fuel ratio is not the actual air-fuel ratio at that time but a predetermined air-fuel ratio set in advance. For example, even if the actual air-fuel ratio is a lean air-fuel ratio, the estimated value of the engine output at the stoichiometric air-fuel ratio (an air-fuel ratio of around 14.7) or the output air-fuel ratio (the air-fuel ratio of 12.0 to 13.0 that provides a high output) Can be calculated as the maximum torque Pi _MAX .

If the air-fuel ratio that is a precondition for calculating the maximum torque Pi _MAX is different, the value of the calculated maximum torque Pi _MAX is also different as in the case where the ignition timing is different. On the other hand, as shown by broken lines in FIG. 4, the maximum torque Pi _MAX corresponding to the air-fuel ratio can be calculated by setting a graph corresponding to a plurality of air-fuel ratios in advance. Therefore, the maximum torque calculation unit 2a may be configured to calculate the maximum torque Pi _MAX according to the rotation speed Ne and the air-fuel ratio.

Further, the same applies to the maximum valve lift amount and valve timing of the intake valve 14 and the exhaust valve 15, and the optimal valve timing and the optimal maximum valve lift amount (that is, the maximum valve lift amount that causes the engine to generate the largest torque, The maximum torque Pi _MAX at the time of the valve timing may be calculated, or the maximum torque Pi _MAX generated in the engine 10 at the maximum valve lift amount and valve timing at that time may be calculated. Also in this case, as shown by a broken line in FIG. 4, a graph corresponding to a plurality of maximum valve lift amounts and valve timings is set in advance, whereby the maximum torque Pi _MAX corresponding to the maximum valve lift amount and valve timing is set. Is possible. Therefore, the maximum torque calculator 2a may be configured to calculate the maximum torque Pi _MAX according to the rotational speed Ne, the maximum valve lift amount, and the valve timing.

The target torque calculator 2b calculates the target torque Pi _TGT based on the rotational speed Ne, the accelerator opening A _PS , no-load loss, and the like. The target torque Pi _TGT corresponds to, for example, the torque required by the driver of the vehicle or the external load device for the engine 10, and the target value of the torque to be output by the engine 10 is converted into the indicated mean effective pressure Pi. Value. Here, it is assumed that a correspondence map, a mathematical expression, and a relational expression of the rotational speed Ne, the accelerator opening A _PS , the no-load loss and the like and the target torque Pi _TGT are set in advance. The target torque calculator 2b calculates the target torque Pi _TGT based on such a relationship. The value of the target torque Pi _TGT calculated here is transmitted to the ratio calculation unit 2c.

The ratio calculator 2c calculates a pressure ratio equivalent value A based on the maximum torque Pi _MAX calculated by the maximum torque calculator 2a and the target torque Pi _TGT calculated by the target torque calculator 2b. The pressure ratio equivalent value A is given as a ratio of the target torque Pi _TGT to the maximum torque Pi _{MAX as} shown in the following formula 1. The pressure ratio equivalent value A calculated here is transmitted to the virtual value calculation unit 3.
Pressure ratio equivalent value A = (Target torque Pi _TGT / Maximum torque Pi _MAX ) ... (Formula 1)

  The relationship between the pressure ratio equivalent value A and the actual pressure ratio C of the throttle valve 23 is graphed and shown in FIG. This graph plots the relationship between the pressure ratio equivalent value A and the pressure ratio C when the maximum speed of the intake valve 14 is changed with the rotational speed Ne, ignition timing, and air-fuel ratio being constant. is there. The horizontal and vertical axes of the graph are the pressure ratio equivalent value A and the pressure ratio C, respectively, and the white circles arranged in dotted lines are the points where the pressure ratio equivalent value A and the pressure ratio C are the same value (C = A Points on a straight line graph).

In this graph, the results when the maximum valve lift amount of the intake valve 14 is increased in four stages of L ₁ , L ₂ , L ₃ , and L ₄ in order are expressed by a thin broken line, a thin solid line, a thick broken line, and a thick solid line. ing. Each of the four graphs has a shape substantially along a dotted white circle. That is, a correlation independent of the maximum valve lift amount is recognized between the pressure ratio equivalent value A and the pressure ratio C, and the pressure ratio equivalent value A can be used as an alternative parameter for the pressure ratio C.

[2-2. Virtual value calculator]
The virtual value calculation unit 3 (virtual value calculation means) uses the pressure ratio equivalent value A obtained by the pressure ratio equivalent value calculation unit 2 and the actually measured values of the intake system pressure (that is, the intake manifold pressure P _IM and the atmospheric pressure P _BP ). Based on this, the virtual value of each pressure is calculated. As shown in FIG. 2, the virtual value calculation unit 3 includes a pressure loss calculation unit 3a, a virtual intake manifold pressure calculation unit 3b, and a virtual atmospheric pressure calculation unit 3c.

The pressure loss calculation unit 3 a calculates a pressure loss P _LOSS (pressure loss amount) lost in the intake passage 24 upstream of the throttle valve 23. Here, a correspondence map, a mathematical expression, and a relational expression between the intake flow rate Q and the pressure loss P _LOSS are set in advance, and the pressure loss calculation unit 3a calculates the pressure loss P _LOSS based on such a relationship. The correspondence relationship between the intake flow rate Q and the pressure loss P _LOSS is such that, for example, the pressure loss P _LOSS is proportional to the square of the intake flow rate Q, as shown in FIG. In consideration of the ambient temperature and atmospheric pressure P _BP, it may be more accurately calculates the pressure loss P _LOSS configuration. The value of the pressure loss P _LOSS calculated here is transmitted to the virtual intake manifold pressure calculation unit 3b and the virtual atmospheric pressure calculation unit 3c.

Virtual intake manifold pressure calculating unit 3b is for calculating the a intake manifold pressure theoretical estimated from the actually measured atmospheric pressure P _BP and the pressure ratio equivalent value A virtual intake manifold pressure VP _IM. Here, the virtual intake manifold pressure VP _IM is calculated in accordance with Equation 2 below. Those from the atmospheric pressure P _BP minus pressure loss P _LOSS corresponds to the upstream pressure of the throttle valve 23, which multiplied by the pressure ratio equivalent value A in is the virtual intake manifold pressure VP _IM. Here computed value of virtual intake manifold pressure VP _IM is transmitted to the determination unit 4 and the control unit 5.

Virtual atmospheric pressure calculating unit 3c is for calculating the atmospheric pressure of the theoretical estimated from the actually measured intake manifold pressure P _IM and the pressure ratio equivalent value A virtual atmospheric pressure VP _BP. Here, the virtual atmospheric pressure VP _BP is calculated according to the following Equation 3. Intake manifold pressure P _IM divided by the pressure ratio equivalent value A and corresponds to the upstream pressure of the throttle valve 23, which the value obtained by adding the pressure loss P _LOSS to is the virtual atmospheric pressure VP _BP. Here computed value of virtual atmospheric pressure VP _BP is transmitted to the determination unit 4 and the control unit 5.

[2-3. Judgment unit]
The determination unit 4 (determination means) determines a failure of the pressure system sensor based on the actual measurement value and the virtual value. As shown in FIG. 2, the determination unit 4 includes an intake manifold pressure sensor determination unit 4a and an atmospheric pressure sensor determination unit 4b.
Intake manifold pressure sensor determination unit 4a compares the with the intake manifold pressure P _IM virtual intake manifold pressure VP _IM, is to determine the failure of the intake manifold pressure sensor 33. Here, the larger the difference between the intake manifold pressure P _IM and virtual intake manifold pressure VP _IM, it is determined that there is a high possibility of a failure of the intake manifold pressure sensor 33.

For example, when containing the value of the intake manifold pressure P _IM within a predetermined error X around the virtual intake manifold pressure VP _IM, it is determined that the intake manifold pressure sensor 33 is normal (not failed). On the other hand, and when the value of the intake manifold pressure P _IM is greater than the value obtained by adding a predetermined error X in the virtual intake manifold pressure VP _IM, when the virtual intake manifold pressure VP _IM smaller than a value obtained by subtracting a predetermined error X, or their state Is continued for a predetermined time, it is determined that the intake manifold pressure sensor 33 has failed. The result of the failure determination of the intake manifold pressure sensor 33 is transmitted to the control unit 5.

Note that FIG. 7 is a horizontal axis and imaginary intake manifold pressure VP _IM, is a graph the vertical axis the intake manifold pressure P _IM. On this graph, it can be determined that the combination of the virtual intake manifold pressure VP _IM and intake manifold pressure P _IM is the case within the shaded area, intake manifold pressure sensor 33 has failed. Alternatively, it may be determined that the intake manifold pressure sensor 33 has failed when the state within the hatched area continues for a predetermined time.

The atmospheric pressure sensor determination unit 4b compares the atmospheric pressure P _BP and the virtual atmospheric pressure VP _BP to determine a failure of the atmospheric pressure sensor 34. The determination method here is the same as the determination method in the intake manifold pressure sensor determination unit 4a. The greater the difference between the atmospheric pressure P _BP and the virtual atmospheric pressure VP _BP , the higher the possibility of failure of the atmospheric pressure sensor 34. It is determined.

For example, when the value of the atmospheric pressure P _{BP is} within the range of the predetermined error Y centered on the virtual atmospheric pressure VP _BP , it is determined that the atmospheric pressure sensor 34 is normal (no failure). On the other hand, when the value of the atmospheric pressure P _BP is greater than the value obtained by adding a predetermined error Y virtual atmospheric pressure VP _BP or when the virtual atmospheric VP _BP smaller than a value obtained by subtracting a predetermined error Y or their state, Is continued for a predetermined time, it is determined that the atmospheric pressure sensor 34 has failed. The result of the failure determination of the atmospheric pressure sensor 34 is transmitted to the control unit 5.

[2-4. Control unit]
The control unit 5 (control means) controls the output of the engine 10 based on the intake manifold pressure P _IM , the atmospheric pressure P _BP , the virtual intake manifold pressure VP _IM and the virtual atmospheric pressure VP _BP . Here, when the intake manifold pressure sensor 33 the determination unit 4 is determined to have failed, the virtual intake manifold pressure VP _IM instead of the intake manifold pressure P _IM is used, the engine 10 is controlled. If the determination unit 4 determines that the atmospheric pressure sensor 34 has failed, the virtual atmospheric pressure VP _BP is used instead of the atmospheric pressure P _BP , and the engine 10 is controlled. Various specific methods of using these pressure information are conceivable, but in this embodiment, there are two ways of using these pressure information for calculating the no-load loss and for using the target throttle opening. Will be described.

(A) No-load loss is a loss in the no-load state of the engine 10. The no-load loss includes mechanical friction loss, intake loss, exhaust loss, and the like. In the present embodiment, the torque corresponding to the loss in the no-load state is referred to as no-load loss. The control unit 5 calculates the torque acting as a load on the output shaft of the engine 10 in the idling state as no-load loss.
The control unit 5 calculates the no-load loss based on the rotational speed Ne of the engine 10 and the relative pressure ΔP of the surge tank 21 part. Here, the no-load loss is calculated based on, for example, a preset correspondence map or formula of the rotational speed Ne, the relative pressure ΔP, and the no-load loss. The no-load loss value calculated here is used for calculating the target torque Pi _TGT during idling or normal driving. Note that the no-load loss calculated here may be calculated using the cooling water temperature WT and the oil temperature OT.

If the intake manifold pressure sensor 33 and atmospheric pressure sensor 34 is not both failed, the relative pressure ΔP of the surge tank 21 parts, as shown in equation 4 below, and a value obtained by subtracting the intake manifold pressure P _IM from atmospheric pressure P _BP Is done. On the other hand, the relative pressure ΔP in the case of being determined that the intake manifold pressure sensor 33 is faulty, as shown in Equation 5 below, is a value obtained by subtracting the virtual intake manifold pressure VP _IM from atmospheric P _BP. The relative pressure ΔP in the case of being determined that the atmospheric pressure sensor 34 is faulty, as shown in Equation 6 below, is a value obtained by subtracting the intake manifold pressure P _IM virtual atmospheric VP _BP.

Relative pressure ΔP = (atmospheric pressure P _BP -intake manifold pressure P _IM ) (Equation 4)
Relative pressure ΔP = (Atmospheric pressure P _BP −Virtual intake manifold pressure VP _IM ) (Expression 5)
Relative pressure ΔP = (virtual atmospheric pressure VP _BP -intake manifold pressure P _IM ) (Expression 6)

The no-load loss is calculated based on the relative pressure ΔP thus obtained, and the no-load loss is reflected in the target torque Pi _TGT . Therefore, an appropriate target torque Pi _TGT is calculated regardless of whether the intake manifold pressure sensor 33 or the atmospheric pressure sensor 34 is broken, and the controllability of the engine 10 is improved.

(B) The control unit 5 controls the throttle opening of the throttle valve 23 based on the target torque Pi _TGT calculated by the target torque calculation unit 2b. Here, the air amount required for the engine 10 to output the target torque Pi _TGT is calculated as the target air amount, and the target flow rate of the intake air to be passed through the throttle valve 23 is calculated based on the target air amount. . Further, the flow velocity V of the intake air in the throttle valve 23 is calculated based on the pressure state of the intake system, and the throttle opening is calculated from the target flow rate and the flow velocity V. The flow velocity V is calculated based on the pressure ratio C of the throttle valve 23 part.

When both the intake manifold pressure sensor 33 and the atmospheric pressure sensor 34 have not failed, the control unit 5 determines the throttle valve 23 based on the atmospheric pressure P _BP , the intake manifold pressure P _IM and the pressure loss P _LOSS as shown in the following expression 7. The pressure ratio C of the part is calculated. On the other hand, if it is determined that the intake manifold pressure sensor 33 is faulty, as shown in Equation 8, the pressure ratio C using a virtual intake manifold pressure VP _IM instead of the intake manifold pressure P _IM in Formula 7 Calculate. If it is determined that the atmospheric pressure sensor 34 is malfunctioning, the pressure ratio C is calculated using the virtual atmospheric pressure VP _BP instead of the atmospheric pressure P _{BP in} Equation 7, as shown in Equation 9. Calculate.

The controller 5 calculates the intake air flow velocity V based on the pressure ratio C obtained by the above calculation. In the control unit 5, for example, a map and a mathematical expression in which the correspondence relationship between the pressure ratio C and the flow velocity V is defined, and a map and a mathematical expression in which the correspondence relationship between the target flow rate and the flow velocity V and the throttle opening are defined are recorded. Yes. Based on these, the flow velocity V is calculated from the pressure ratio C, and the throttle opening is calculated.
Therefore, an appropriate throttle opening is calculated regardless of whether or not the intake manifold pressure sensor 33 and the atmospheric pressure sensor 34 are broken, and the controllability of the engine 10 is improved.

[3. Action, effect]
As shown in FIG. 5A, the pressure ratio equivalent value A is correlated with the pressure ratio C of the throttle valve 23 part. Based on this correlation, the virtual from intake manifold pressure P _IM in the engine control device 1 described above atmospheric pressure VP _BP is calculated, the virtual intake manifold pressure VP _IM is calculated from the atmospheric pressure P _BP. Virtual intake manifold pressure VP _IM, since the value obtained from the actual atmospheric pressure P _BP and the pressure ratio equivalent value A, reflects the parameter with the same characteristics as the actual intake manifold pressure P _IM, the output of the atmospheric pressure sensor 34 as long as is appropriate, the theoretical value close to intake manifold pressure P _IM. Similarly, the virtual atmospheric pressure VP _BP is a parameter having the same characteristics as the actual atmospheric pressure P _BP and has a theoretical value close to the atmospheric pressure P _BP as long as the output of the intake manifold pressure sensor 33 is appropriate.

(1) Thus, in the engine control apparatus 1 described above, a virtual value is calculated based on the pressure ratio equivalent value A and the actual measurement value. Thereby, the theoretical magnitude of the intake system pressure can be accurately estimated with a simple calculation configuration that does not require a complicated intake system model. Therefore, the reliability of control can be improved regardless of whether or not the intake manifold pressure sensor 33 or the atmospheric pressure sensor 34 has failed.
In addition, if one of the intake manifold pressure P _IM and the atmospheric pressure P _BP is measured, the other virtual value can be acquired, so either the intake manifold pressure sensor 33 or the atmospheric pressure sensor 34 can be omitted. Therefore, the cost can be reduced. Note that the reliability of control can be improved by omitting a sensor having low reliability.

(2) Further, in the engine control device 1, the intake manifold pressure P _IM and the atmospheric pressure P _BP are both measured, and the virtual intake manifold pressure VP _IM are the respective virtual value and the virtual atmospheric pressure VP _BP is computed Yes. Thereby, a virtual value can be used as an alternative to the actual measurement value at the time of failure. For example, when the intake manifold pressure sensor 33 has failed, as a substitute for the intake manifold pressure P _IM seeking virtual intake manifold pressure VP _IM from the measured value of the atmospheric pressure sensor 34, it can be calculated no-load loss and the throttle opening The operating state of the engine 10 that is the same as before the failure can be maintained. Therefore, the fail safe function of the engine 10 can be improved, and the reliability of control can be improved.

(3) Further, in the engine control device 1, by comparing the intake manifold pressure P _IM detected by the intake manifold pressure sensor 33 and the virtual intake manifold pressure VP _IM, to accurately determine a failure of the intake manifold pressure sensor 33 Can do. For example, even when the intake manifold pressure P _IM is within the normal variation range, when the difference between the virtual intake manifold pressure VP _IM is large, it can be determined that the intake manifold pressure sensor 33 fails, determination precision Can be improved. Similarly, a failure of the atmospheric pressure sensor 34 can be accurately determined by comparing the atmospheric pressure P _BP detected by the atmospheric pressure sensor 34 with the virtual atmospheric pressure VP _BP .

(4) Even if you omit the atmospheric pressure sensor 34, it is possible to determine the virtual atmospheric pressure VP _BP if there is intake manifold pressure sensor 33. On the other hand, since the pressure detected by the intake manifold pressure sensor 33 is the pressure of the intake air that has passed through the intake passage 24, it fluctuates with a slight delay from the actual fluctuation of the atmospheric pressure. Such an intake air delay may reduce the controllability of the engine 10.

On the other hand, in the engine control apparatus 1 described above, since the atmospheric pressure sensor 34 is mounted without being omitted, generation of a virtual value calculation error and a decrease in controllability of the engine 10 due to an intake air delay are suppressed. be able to. In addition, by using the measured value of the atmospheric pressure _PBP , there is an advantage that the value of the no-load loss can be calculated with high accuracy and the calculation accuracy of the pressure ratio equivalent value A can be improved.

(5) In the engine control apparatus 1 described above, a pressure obtained by subtracting the pressure loss P _LOSS from the atmospheric pressure P _BP is used as the pressure corresponding to the upstream pressure of the throttle valve 23, and the pressure loss P based on the intake flow rate Q is used. _LOSS is calculated. Thus, it is possible to grasp precisely the amount of pressure drop in the intake passage 24 upstream of the throttle valve 23, it is possible to improve the calculation accuracy of the virtual intake manifold pressure VP _IM and virtual atmospheric pressure VP _BP.

(6) Regarding the calculation method of the pressure ratio equivalent value A, the engine control apparatus 1 calculates the pressure ratio equivalent value A using the maximum torque Pi _MAX and the target torque Pi _TGT at that time. . These maximum torque Pi _MAX and target torque Pi _TGT are parameters that can be used in torque-based control other than intake amount control such as control of fuel injection amount, injection timing, and ignition timing, for example. There is an advantage that the control program and the algorithm can be simplified easily.

[4. Modified example]
[4-1. Calculation of pressure ratio equivalent value using filling efficiency]
Regardless of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each structure of this embodiment can be selected as needed, or may be combined appropriately.
In the engine control apparatus 1 described above, the pressure ratio equivalent value A is calculated using the maximum torque Pi _MAX and the target torque Pi _TGT of the engine 10, but the amount of air introduced into the cylinder 19 is used instead of the torque. It is also possible to perform the same calculation.

For example, instead of the maximum torque Pi _MAX and the target torque Pi _TGT of the above-described embodiment, the second pressure ratio equivalent value B is calculated using the maximum charging efficiency Ec _MAX and the target charging efficiency Ec _TGT, and the second pressure ratio It is conceivable to use the equivalent value B as an alternative parameter for the pressure ratio C. The maximum charging efficiency Ec _MAX is the charging efficiency Ec corresponding to the maximum torque Pi _MAX in the above-described embodiment, and is calculated based on the amount of air required to generate the maximum torque Pi _MAX in the engine 10. Efficiency Ec (charging efficiency Ec when the throttle opening is fully opened). The target charging efficiency Ec _TGT is charging efficiency Ec corresponding to the target torque Pi _TGT, a charging efficiency Ec calculated based on the amount of air required to generate the target torque Pi _TGT engine 10. Using these parameters, the ratio of the target charging efficiency Ec _TGT to the maximum charging efficiency Ec _MAX can be set to the second pressure ratio equivalent value B (B = Ec _TGT / Ec _MAX ).

  Here, FIG. 5B illustrates the relationship between the second pressure ratio equivalent value B confirmed through the tests by the present inventors and the actual pressure ratio C of the throttle valve 23 part. Similar to FIG. 5A, this graph shows the second pressure ratio equivalent values B when the rotational speed Ne and air-fuel ratio of the engine 10 are constant and the maximum valve lift amount of the intake valve 14 is changed. The relationship with the pressure ratio C is plotted.

  Each of the four graphs with different maximum valve lifts has a shape along a dotted white circle, and the correlation between the second pressure ratio equivalent value B and the pressure ratio C does not depend on the maximum valve lift. Is recognized. Therefore, even when the second pressure ratio equivalent value B is used instead of the pressure ratio C, the same operations and effects as those of the above-described embodiment are achieved.

In this case, the maximum torque calculation unit 2a in the above-described embodiment may be configured to control the maximum charging efficiency Ec _MAX corresponding to the maximum torque Pi _MAX . The maximum charging efficiency Ec _MAX is calculated based on the rotational speed Ne of the engine 10 and the intake flow rate Q, as well as the fuel injection amount, ignition timing, maximum valve lift amount, valve timing, and the like. Alternatively, map defining the correspondence between the maximum torque Pi _MAX and the maximum charging efficiency Ec _MAX, based on the mathematical expression or the like, may be obtained the maximum charging efficiency Ec _MAX from the maximum torque Pi _MAX.

Further, the target torque calculation unit 2b may be configured to calculate a target charging efficiency Ec _TGT corresponding to the target torque Pi _TGT . For example, the target charging efficiency Ec _TGT may be calculated based on the rotational speed Ne, the accelerator opening A _PS , no-load loss, etc., or a map that defines the correspondence between the target torque Pi _TGT and the target charging efficiency Ec _TGT The target charging efficiency Ec _TGT may be obtained from the target torque Pi _TGT based on mathematical formulas and the like.

These maximum charging efficiency Ec _MAX, using the target charging efficiency Ec _TGT, ratio calculation unit 2c is, calculates the ratio of the target charging efficiency Ec _TGT for the maximum charging efficiency Ec _MAX as the second pressure ratio equivalent value B. In the subsequent calculation, by using the second pressure ratio equivalent value B in place of the pressure ratio equivalent value A, a virtual value can be calculated in the same manner as in the above embodiment, or failure determination of the pressure sensors Can be implemented. Further, by utilizing the correlation between the second pressure ratio equivalent value B and the pressure ratio C, a complicated map or table corresponding to various operating states of the engine 10 becomes unnecessary, and data related to the calculation of the throttle opening is obtained. The ROM capacity to be stored can be reduced.

[4-2. Others]
In the above-described embodiment, as illustrated in FIG. 7, when the difference between the actual measurement value and the virtual value is larger than the predetermined error X, for example, the control in which it is determined that the sensor that actually measured the actual measurement value has failed is illustrated. However, the specific failure determination method is not limited to this. For example, the width of the range in which the sensor is determined to be normal may be changed according to the actual measurement value at that time. Alternatively, the value of the predetermined error X may not be a fixed value but a variable set according to another parameter.

In the above-described embodiment, the calculation method of the maximum torque Pi _MAX has been described mainly focusing on the relationship between the engine rotation speed Ne and the maximum torque Pi _MAX as shown in FIG. However, the maximum torque Pi _MAX of the engine 10 changes not only according to the engine speed Ne but also according to the ignition timing, the maximum valve lift amount, the valve timing, and the air-fuel ratio as described above. Therefore, the maximum torque Pi _MAX may be calculated or corrected according to the maximum valve lift amount and valve timing at the time when the maximum torque Pi _MAX is calculated by the maximum torque calculator 2a. Thereby, the correlation between the pressure ratio equivalent value A and the pressure ratio C can be further increased, the controllability of the throttle valve 23 can be further improved, and the control reliability can be improved.

On the other hand, even if the maximum valve lift amount and valve timing at the time of calculation are not used, the correlation between the pressure ratio equivalent value A and the pressure ratio C is ensured. For example, as shown in FIGS. 5A and 5B, the correlation between the pressure ratio equivalent value A and the pressure ratio C and the correlation between the second pressure ratio equivalent value B and the pressure ratio C are the maximum valve lift amount. Does not depend on. Therefore, it is not always necessary to reflect the actual control angle θ _VVL and phase angle θ _VVT in the calculation of the maximum torque Pi _MAX .

The same applies to the ignition timing and air-fuel ratio. By calculating the maximum torque Pi _MAX according to these parameters, a more accurate value of the maximum torque Pi _MAX can be obtained, and the pressure ratio equivalent value A And the pressure ratio C can be further increased. Therefore, the reliability of control can be improved.

The maximum torque Pi _MAX at the ignition timing at the time of calculation may be calculated, the torque generated when ignition is performed at the optimal ignition timing may be set to the maximum torque Pi _MAX , or knocking may be performed. Considering the possibility, the maximum torque Pi _MAX may be used as the torque generated when the ignition timing is slightly delayed from the optimal ignition timing. The correlation between the pressure ratio equivalent value A and the pressure ratio C is strengthened most when the ignition is performed at the optimum ignition timing. A correlation can be recognized.

Further, in the above-described embodiment, the example in which the pressure ratio equivalent value A is calculated using the maximum torque Pi _MAX and the target torque Pi _TGT expressed by the indicated mean effective pressure Pi is illustrated, but a specific pressure ratio equivalent value is illustrated. The calculation method of A is not limited to this. For example, the pressure ratio equivalent value A may be calculated using the net average effective pressure Pe or the torque value generated in the crankshaft 17 instead of the indicated average effective pressure Pi. Further, the second pressure ratio equivalent value B may be calculated using an air amount (volume or mass of air), volume efficiency, intake air flow rate, or the like instead of the charging efficiency Ec in the above-described modification.

DESCRIPTION OF SYMBOLS 1 Engine control apparatus 2 Pressure ratio equivalent value calculating part (pressure ratio equivalent value calculating means)
3 Virtual value calculation unit (virtual value calculation means)
4. Judgment part (determination means)
5 Control unit (control means)
32 Air flow sensor (flow rate detection means)
33 In manifold pressure sensor (measured value detection means)
34 Atmospheric pressure sensor (Measurement value detection means)

Claims (10)

An actual measurement value detecting means for detecting an actual measurement value of at least one of the upstream pressure and the downstream pressure in the throttle valve portion of the engine;
Pressure ratio equivalent value calculating means for calculating a ratio of a target torque equivalent value that is a torque required for the engine to a maximum torque equivalent value of the engine as a pressure ratio equivalent value;
Based on the measured value detected by the measured value detection means and the pressure ratio equivalent value calculated by the pressure ratio equivalent value calculation means, at least one of the upstream pressure and the downstream pressure is calculated. An engine control device comprising virtual value calculation means. The measured value detection means detects the measured values of both the upstream pressure and the downstream pressure,
The engine control apparatus according to claim 1, further comprising a control unit that controls the engine based on the virtual value calculated by the virtual value calculation unit when the actual value detection unit fails. 3. The engine control device according to claim 2, further comprising a determination unit that determines a failure of the actual value detection unit by comparing the actual value and the virtual value. The actual measurement value detecting means detects an actual measurement value of atmospheric pressure as the upstream pressure,
The engine according to any one of claims 1 to 3, wherein the virtual value calculation means calculates a virtual intake manifold pressure based on the pressure ratio equivalent value and the measured value of the atmospheric pressure. Control device. Comprising a flow rate detecting means for detecting the intake flow rate of the engine,
The engine according to any one of claims 1 to 4, wherein the virtual value calculation means calculates the other virtual value based on the intake flow rate detected by the flow rate detection means. Control device. The pressure ratio equivalent value calculation means calculates the torque generated in the engine as the maximum torque equivalent value with the amount of air introduced into the engine, and a target torque set based on the accelerator operation amount of the engine 6 is calculated as the target torque equivalent value, and the engine control device according to claim 1. The pressure ratio equivalent value calculating means uses the maximum charging efficiency of the engine as the maximum torque equivalent value, and uses the target charging efficiency calculated based on the amount of air introduced into the engine as the target torque equivalent value. The engine control device according to claim 1, wherein the pressure ratio equivalent value is calculated. The engine according to any one of claims 1 to 7, wherein the pressure ratio equivalent value calculating means calculates the maximum torque equivalent value according to a valve lift amount or a valve timing of an intake / exhaust valve. Control device. 9. The pressure ratio equivalent value calculating means calculates a torque generated in the engine when the ignition timing is an optimum ignition timing as the maximum torque equivalent value. The engine control apparatus described in 1. The pressure ratio equivalent value calculating means calculates a maximum torque generated in the engine during combustion at a predetermined air / fuel ratio set in advance as the maximum torque equivalent value. The engine control device according to claim 1.

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