WO2004013478A1

WO2004013478A1 - Engine controller

Info

Publication number: WO2004013478A1
Application number: PCT/JP2003/004664
Authority: WO
Inventors: Michihisa Nakamura
Original assignee: Yamaha Hatsudoki Kabushiki Kaisha
Priority date: 2002-07-31
Filing date: 2003-04-11
Publication date: 2004-02-12
Also published as: AU2003236226A1; TWI221882B; TW200403386A

Abstract

An engine controller in which abnormality of intake pressure can be detected by making it possible to detect the abnormality when an intake pressure sensor is removed from an inlet pipe. Intake pressure variation ΔP during two revolutions, i.e. one cycle, of the crankshaft of a four-stroke engine is calculated and a decision is made that the intake pressure is abnormal when a state where the intake pressure variation ΔP is not higher than a threshold level ΔP0 continues for a specified value CNT0 or more. Abnormality of intake pressure can be detected more reliably when the intake pressure variation ΔP is set smaller for a lower engine r.p.m. and set smaller for a larger throttle opening.

Description

Description Engine control device Technical field

The present invention relates to an engine control device for controlling an engine, and is particularly suitable for controlling an engine having a fuel injection device for injecting fuel. Background art

In recent years, with the spread of fuel injectors called injectors, it has become easier to control the timing of fuel injection and the amount of injected fuel, that is, the air-fuel ratio, etc., and to achieve higher output, lower fuel consumption, and cleaner exhaust gas. It has become possible to promote. Of these, especially for the timing of fuel injection, strictly speaking, it is common to detect the state of the intake valve, that is, generally the phase state of the power shaft, and inject fuel accordingly. However, a so-called cam sensor for detecting the phase state of a camshaft is expensive, and particularly in a motorcycle or the like, it cannot be adopted because of a problem such as a large cylinder head. Therefore, for example, Japanese Patent Application Laid-Open No. H10-227252 proposes an engine control device that detects a phase state of a crankshaft and an intake pressure, and detects a stroke state of a cylinder therefrom. Therefore, by using this conventional technology, it is possible to detect the stroke state without detecting the phase of the camshaft, and it is possible to control the injection timing of the twisting material and the like according to the stroke state. It becomes possible.

By the way, the above-mentioned intake pressure can be detected by intake pressure detecting means such as an intake pressure sensor. For example, when the intake pressure detecting means is disengaged from the intake pipe and is released to the atmosphere, it always becomes large. Atmospheric pressure will be detected. Since atmospheric pressure is generally the detection area of the intake pressure detecting means, it has been found that an abnormality of the intake pressure detecting means cannot be detected as it is.

The present invention has been developed to solve the above problems, and an object of the present invention is to provide an engine control device capable of reliably detecting an abnormality of intake pressure detecting means. Disclosure of the invention

Thus, the engine control device according to claim 1 of the present invention includes a crankshaft phase detecting means for detecting a phase of a crankshaft, an intake pressure detecting means for detecting an intake pressure in an intake pipe of an engine, and the crankshaft. Engine control means for controlling the operation state of the engine based on the crankshaft phase detected by the shaft phase detection means and the intake pressure detected by the intake pressure detection means, and the engine control means detecting the crankshaft phase detection means When the crankshaft rotates from the phase of the crankshaft, and when the fluctuation of the intake pressure within two revolutions of the crankshaft detected by the intake pressure detecting means is less than or equal to a predetermined value, Detecting means force << intake pressure abnormality detecting means for detecting an abnormality. The term "within two crankshaft rotations" as used herein means a maximum of two rotations of the crankshaft, and when the intake pressure fluctuation detected therein is equal to or less than a predetermined value, the intake pressure detecting means is abnormal. Assume that there is. Further, the engine control device according to claim 2 of the present invention according to claim 1 further includes an engine speed detecting means for detecting an engine speed, wherein the intake pressure abnormality detecting means comprises: The predetermined value of the intake pressure fluctuation is set to be smaller, as the engine speed power detected by the engine speed detecting means << smaller. Further, the engine control device according to claim 3 of the present invention according to claim 1 or 2, further comprising a throttle opening detecting means for detecting an opening of a throttle valve, wherein the intake pressure abnormality detecting means is provided. Is characterized in that the larger the opening of the throttle valve detected by the throttle opening detecting means, the smaller the predetermined value of the intake pressure fluctuation is set. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic configuration diagram of an auto / key engine and its control device.

Figure 2 is an explanatory view of the principle of delivering crank pulse in the engine of FIG. ^1.

FIG. 3 is a block diagram showing an embodiment of the engine control device of the present invention.

FIG. 4 is an explanatory diagram for detecting a stroke state from the phase of the crankshaft and the intake pressure. FIG. 5 is a block diagram of the intake air amount calculation unit. FIG. 6 is a control map for obtaining the mass flow rate of the intake air from the P and the air pressure.

FIG. 7 is a block diagram of a fuel injection amount calculation unit and a fuel behavior model.

FIG. 8 is an explanatory diagram showing a state where the intake pressure sensor is attached to the intake pipe.

FIG. 9 is an explanatory diagram showing the relationship between the output value of the intake pressure sensor and the intake pressure.

FIG. 10 is a flowchart showing a calculation process for detecting an intake pressure abnormality performed by the engine control unit of FIG.

FIG. 1 is a control map used in the arithmetic processing of FIG.

FIG. 12 is an explanatory diagram of an intake pressure signal when the intake pressure sensor comes off. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described.

FIG. 1 is a schematic configuration showing an example of an engine for an auto-knob and its control device. This engine 1 is a four-cylinder four-stroke engine, with a cylinder body 2, a crankshaft 3, a piston 4, a combustion chamber 5, an intake pipe 6, an intake valve 7, an exhaust pipe 8, an exhaust valve 9, a spark plug 10, and an ignition plug. It has a coil 11. A throttle valve 12 that opens and closes according to the accelerator opening is provided in the intake pipe 6, and an injector 13 as a fuel injection device is provided in the intake pipe 6 downstream of the throttle valve 12. Have been. The injector 13 is connected to a filter 18, a fuel pump 17, and a pressure control valve 16 provided in a fuel tank 19. Note that the engine 1 is a so-called independent intake system, and the aforementioned injectors 13 are provided in each intake pipe 6 of each cylinder.

The operating state of the engine 1 is controlled by an engine control unit 15. As means for detecting the control input of the engine control unit 15 and the operating state of the pinch engine 1, the crank angle sensor 20 for detecting the rotation angle of the crankshaft 3, that is, the phase, and the temperature of the cylinder body 2 Alternatively, a cooling water temperature sensor 21 for detecting a temperature of the cooling water, that is, a temperature of the engine body, an exhaust air-fuel ratio sensor 22 for detecting an air-fuel ratio in the exhaust pipe 8, and an intake pressure for detecting an intake pressure in the intake pipe 6. A sensor 24 and an intake air temperature sensor 25 for detecting the temperature in the intake pipe ⁶ , that is, the intake air temperature, are provided. Then, the engine control unit 15 receives the detection signals of these sensors and sends the control signals to the fuel pump 17, the pressure control valve 16, the injector 13, and the ignition coil 11. Is output.

Here, the principle of the crank angle signal output from the crank angle sensor 20 will be described. In this embodiment, as shown in FIG. 2a, a plurality of teeth 23 are protruded at substantially equal intervals on the outer periphery of the crankshaft 3, and the approach thereof is detected by a crank angle sensor 20 such as a magnetic sensor, and an electric Performs the appropriate processing and sends out the nourse signal. The circumferential pitch between each tooth 23 is 30 ° in terms of the phase (rotation angle) of the crankshaft 3, and the circumferential width of each tooth 23 is in the phase (rotation angle) of the crankshaft 3. To 10 °. However, only one portion does not follow this pitch, and there are portions where the pitch of the other teeth 23 is twice as large. As shown by the two-dot chain line in FIG. 2a, it is originally a special setting where there is no tooth in the toothed part, and this part corresponds to unequal spacing. Hereinafter, this portion is also referred to as a toothless portion.

Accordingly, the signal sequence of each tooth 23 when the crankshaft 3 rotates at a constant speed appears as shown in FIG. 2B. FIG. 2a shows the state at the time of compression top dead center (the same applies to the form of exhaust top dead center). Then, the next / less signal is shown as "1", the next noise signal is shown as "2", and so on. The tooth 23 following the tooth signal of "4" shown in the figure is a tooth missing portion, and it is counted as an extra tooth "I" assuming that a tooth exists. It illustrated "6" to Nan / ring. When Yuku Repeat this in turn so toothless portion to the next / pulse signal shown ^"1 6" approaches, extra and counter Bok one tooth in the same manner as described above Then, for the next tooth 23, the lug signal is ringed with "18" as shown. When the crankshaft 3 rotates twice, all four stroke cycles are completed. After the ring is completed, the ring signal of the next tooth 23 is ringed again with the number “0” shown in the figure.In principle, immediately after the pulse signal of the tooth 23 numbered “0” in the figure, compression is applied. In this way, the detected pulse signal sequence or the single / When the stroke is detected as described later on the basis of the crank / loose, the crank timing can be detected. It is exactly the same even if it is provided on the outer periphery of the member to be used.

On the other hand, the engine control unit 15 is a microcomputer (not shown). It is composed of FIG. 3 is a block diagram showing an embodiment of the engine control arithmetic processing performed by the microphone computer in the engine control unit 15. As shown in FIG. In this calculation process, an engine speed calculating unit 26 for calculating the engine speed from the crank angle signal, and crank timing information for detecting the crank angle signal and the intake pressure signal force, that is, crank timing information for detecting the stroke state. Unit 27, an intake air amount calculation unit 28 that reads crank timing information detected by the crank timing detection unit 27, and calculates an intake air amount from the intake air temperature signal and the intake air pressure signal, and the engine speed calculation unit. By setting a target air-fuel ratio based on the engine speed calculated at 26 and the intake air amount calculated at the intake air amount calculation unit 28 or detecting an acceleration state, the fuel injection amount and the fuel injection amount are determined. A fuel injection amount setting unit 29 for calculating and setting a timing; and a crank timing detected by the crank timing detection unit 27. An injection pulse output unit 30 that reads the It report and outputs an injection pulse corresponding to the fuel injection amount and the fuel injection timing set by the fuel injection amount setting unit 29 to the injector ^13; The crank timing information detected by the crank timing detection unit 27 is read, and ignition is performed based on the engine speed calculated by the engine speed calculation unit 26 and the fuel injection amount set by the fuel injection amount setting unit 29. An ignition timing setting unit 31 for setting a timing, and crank timing information detected by the crank timing detection unit 27 are read, and an ignition noise corresponding to the ignition timing set by the ignition timing setting unit 31 is read by the ignition coil 1. And an ignition pulse output unit 32 that outputs the signal toward 1.

The engine speed calculation unit 26 calculates the rotation speed of the crankshaft, which is the output shaft of the engine, as the engine speed from the time rate of change of the crank angle signal. Specifically, an instantaneous value of the engine speed obtained by dividing the phase between the adjacent teeth 23 by the required crank pulse detection time and an average value of the engine speed obtained from the moving average value are calculated. .

The crank timing detection unit 27 has a configuration similar to that of the stroke determination device described in Japanese Patent Application Laid-Open No. Hei 10-227252, and thereby detects the stroke state of each cylinder, for example, as shown in FIG. And outputs it as crank timing information. In other words, in a four-cycle engine, the crankshaft and the camshaft always rotate at a predetermined phase difference, so that, for example, when the crank / loose is read as shown in FIG. , Mentioned above The fourth crank pulse "9" or "21" shown from the missing portion is either the exhaust stroke or the compression stroke. As is well known, in the exhaust stroke, the exhaust / lube is open and the intake / lube is closed, so the intake pressure is high in the early stage of the compression stroke when the intake pressure is high. Even if the valve is closed, the intake pressure is low in the preceding intake stroke. Accordingly, when the intake pressure is low, the crank / lus of "21" shown in the drawing is in the compression stroke, and immediately after the crank / lusker of "0" shown is obtained, the compression top dead center is obtained. In this way, if any of the stroke states can be detected, the current stroke state can be more finely detected by interpolating between the strokes with the rotational speed of the crankshaft. Further, if the stroke of any one of the cylinders can be detected as described above, the four cylinders of the present embodiment are constantly rotating with a predetermined phase difference, so that the strokes of the other cylinders can be naturally detected.

As shown in FIG. 5, the intake air amount calculation unit 28 includes an intake pressure detection unit 281 that detects intake pressure from the intake pressure signal and the crank timing information, and an intake pressure detection unit 281 that detects a mass flow rate of intake air from the intake pressure. A mass flow rate map storage unit 282 that stores a map, a mass flow rate calculation unit 283 that calculates a mass flow rate according to the detected intake pressure using the mass flow rate map, and an intake air flow rate based on the intake air temperature signal. An intake air temperature detector 284 for detecting a temperature, and a mass for correcting the intake air mass flow from the intake air mass flow calculated by the mass flow calculator 283 and the intake air temperature detected by the intake air temperature detector 284. The flow rate correction unit 285 is provided. That is, since the mass flow rate map is created based on the mass flow rate when the intake air temperature is 20 ° C., for example, the intake air flow rate is calculated by correcting this with the actual intake air temperature (absolute temperature ratio). .

In the present embodiment, the intake air amount is calculated using the intake pressure value between the bottom dead center in the compression stroke and the intake / end closing timing. That is, when the intake valve is opened, the intake pressure and the cylinder pressure are substantially equal, so that the intake pressure, the cylinder volume, and the intake temperature are known, and thus the in-cylinder air mass can be obtained. However, since the intake / lube remains open for a while after the start of the compression stroke, air flows in and out between the cylinder and the intake pipe during this time, and the intake air volume calculated from the intake pressure before BDC May be different from the amount of air actually drawn into the cylinder. Therefore, even when the intake valve is open, no air flows between the cylinder and the intake pipe, and the intake air volume is calculated using the intake pressure during the compression stroke. I do. In order to further strictly consider the effect of the burned gas partial pressure, take into account the effect of the burned gas partial pressure, use the engine speed, and make a correction according to the engine speed obtained through experiments. Also

'Good.

Further, in the present embodiment which is an independent intake system, the mass flow map for calculating the intake air amount uses a relatively linear relationship with the intake pressure as shown in FIG. . This is because it is based on the required air mass force Boyle Charles law (PV = nRT). On the other hand, when the intake pipe is connected to all cylinders, the assumption of intake pressure and cylinder pressure is not established due to the influence of the pressure of the other cylinders. Must be used.

The fuel injection amount setting unit 29 includes a steady-state target air-fuel ratio calculation unit 33 that calculates a steady-state target air-fuel ratio based on the engine speed 26 calculated by the engine speed calculation unit 26 and the intake pressure signal. On the basis of the steady-state target air-fuel ratio calculated by the steady-state target air-fuel ratio calculator 33 and the intake air amount calculated by the intake air amount calculator 28, a constant fuel injection amount and fuel injection timing are calculated. A constant fuel injection amount calculation unit 34, a fuel behavior model 35 used for calculating the steady state fuel injection amount and the fuel injection timing in the steady state fuel injection amount calculation unit 34, the crank angle signal and the intake pressure signal And an acceleration state detecting means 41 for detecting an acceleration state based on the crank timing information detected by the crank timing detection section 27, and according to the acceleration state detected by the acceleration state detection means 41, Engine speed calculating section acceleration fuel injection quantity according to the engine rotational speed calculated at 26 and the acceleration fuel injection quantity calculating section for calculating a fuel injection timing 4 and a 2 and. The fuel behavior model 35 is substantially integrated with the steady-state fuel injection amount calculation unit 34. That is, without the fuel behavior model 35, it is impossible to accurately calculate and set the fuel injection amount and the fuel injection timing in the present embodiment in which the injection in the intake pipe is performed. The fuel behavior model 35 requires the intake air temperature signal, the engine speed and the coolant temperature signal.

The steady-state fuel injection amount calculation unit 34 and the fuel behavior model 35 are configured, for example, as shown in a block diagram of FIG. Here, assuming that the fuel injection amount injected from the injector 13 into the intake pipe 6 and the fuel adhesion rate adhering to the wall of the intake pipe 6 is X, of the fuel injection amount, the fuel injection amount is directly injected into the cylinder. Direct inflow is ((1 -X) XM And the amount of adhesion to the intake pipe wall is (X x lVUi). Some of the deposited fuel flows into the cylinder along the intake pipe wall. Assuming that the remaining amount is the residual fuel amount I JF, _{assuming the} carry-out rate of the residual fuel amount taken away by the intake air flow, the inflow amount carried away and flowing into the cylinder is (XM _FBUF ) .

Therefore, the steady-state fuel injection amount calculation unit 34 first calculates a cooling water temperature correction coefficient K _w from the cooling water temperature T _{w using a} cooling water temperature correction coefficient table. Meanwhile, the relative amount of intake air IV ^, for example, performs a fuel force Ttoruchin for cutting fuel when the throttle opening force "is zero, then the intake air temperature T _A with the temperature corrected air flow rate M _A is calculated, and the target air-fuel ratio AF is calculated. Of multiplying the inverse ratio, further calculates the cooling water temperature correction factor K _w a multiplied by the required fuel inflow amount M _F. In contrast, with obtaining the fuel adhesion rate X by using the fuel deposition rate map from the engine speed New _epsilon and intake pressure, similarly to use the carry-off ratio map from the engine speed N _E and the intake pressure, Te Calculate the carry-out rate. Then, by multiplying the retention away rate τ to the fuel residual quantity IV F obtained in the previous operation to calculate the carried-off amount Micromax _"Alpha fuel, the required fuel flow rate! \ ^ Pressurized et subtracting rltr Symbol fuel directly in Calculate the inflow _MIR, as described above.

Since MM ™ is (1−X) times the fuel injection amount M, the constant fuel injection amount is calculated here by dividing by (1−X). Of the remaining fuel amount M remaining in the intake pipe up to the previous time, ((1)) XM also remains this time, and the fuel adhesion amount (XX

The intake air amount calculated by the intake air amount calculation unit 28 is detected at the end of the intake stroke of the cycle immediately before the intake stroke that enters the explosion (expansion) stroke or at the beginning of the subsequent compression stroke. The steady-state fuel injection amount and the fuel injection timing calculated and set by the steady-state fuel injection amount calculation unit 34 are also the results of the immediately preceding cycle according to the intake air amount. .

Further, the acceleration state detection section 41 has an acceleration state threshold value table. This is performed by calculating a difference value between the intake pressure at the same stroke as the present, specifically, the exhaust stroke or the intake stroke at the same crank angle and the current intake pressure, and determining the value as a predetermined value. Is a threshold value for detecting that the vehicle is in the accelerated state as compared with the value of, and specifically differs for each crank angle. Therefore, to detect the acceleration state, This is performed by comparing a difference value with a predetermined value that differs at each crank angle. The detection of the acceleration state is performed after a predetermined cycle has elapsed since the previous acceleration state was detected.

Further, the acceleration fuel injection amount calculation unit 42, when the acceleration state force << is detected by the acceleration state detection unit 41, the difference value between the current value and the previous value of the intake pressure, and the engine speed N the acceleration fuel injection quantity Micromax _∞ calculated from the three-dimensional map corresponding to the _E. In this embodiment, the fuel injection timing at acceleration is defined as when the acceleration state is detected by the acceleration state detection unit 41, that is, when the acceleration state is detected, the acceleration fuel injection amount M _F _ACC is immediately injected. It shall be.

The ignition timing setting unit 31 calculates a basic ignition timing based on the engine speed calculated by the engine speed calculation unit 26 and the target air-fuel ratio calculated by the target air-fuel ratio calculation unit 33. A timing calculation unit 36, and an ignition timing correction unit 8 that corrects the basic ignition timing calculated by the basic ignition timing calculation unit 36 based on the acceleration fuel injection amount calculated by the acceleration fuel injection amount calculation unit 42. And is provided.

The basic ignition timing calculation unit 36 obtains the ignition timing at which the generated torque force << the largest from the current engine speed and the target air-fuel ratio at that time by searching a map or the like, and calculates the basic ignition timing. That is, the ignition timing calculated by the ignition timing calculation unit 36 is the same as that of the steady-state fuel injection amount calculation unit 34, and is based on the result of the intake stroke of the immediately preceding cycle. Further, the ignition timing correction unit 38 calculates the acceleration fuel injection amount when the acceleration fuel injection amount is added to the constant fuel injection amount in accordance with the acceleration fuel injection amount calculated by the acceleration fuel injection amount calculation unit 42. The cylinder air-fuel ratio is determined, and when the cylinder air-fuel ratio is significantly different from the target air-fuel ratio set by the steady-state target air-fuel ratio calculation unit 33, the cylinder air-fuel ratio, engine speed, and intake pressure are used. The ignition timing is corrected by setting a new ignition timing.

By the way, as shown in FIG. 8, the intake pressure sensor 24 has a pressure guiding tube 23 attached to the intake pipe 6 so as not to be directly exposed to fuel, and is attached to the tip of the pressure guiding tube 23. When the relationship between the output of the intake pressure sensor 24 and the actual intake pressure is as shown in FIG. 9, if only abnormalities such as a disconnection or a short circuit are considered, for example, the upper limit of the output value or the lower limit value The region excluding the vicinity may be regarded as a normal region, and an abnormality may be detected when the output of the intake pressure sensor is not in the normal region. However, for example, from the intake pipe 6 When the intake pressure sensor 24 has come off together with the pressure guiding tube 23, the intake pressure sensor 24 is released to the atmosphere, and detects and outputs the atmospheric pressure. Normally, the output value of the intake pressure sensor 24 includes the atmospheric pressure as shown in FIG. 9, so it is assumed that the abnormality is merely when the intake pressure sensor 24 is not in the normal range. No error can be detected. Therefore, in the engine control unit 15, the abnormality of the intake pressure sensor is detected by the arithmetic processing shown in FIG. This calculation process is performed by, for example, an interrupt process every two rotations of the crankshaft. Further, in this arithmetic processing, although no step is particularly provided for communication, information necessary for the arithmetic is read as needed, and the result of the arithmetic is stored as needed.

In this calculation process, first, in step S1, the intake pressure for two rotations of the crankshaft is read, for example, each time the crank pulse is rotated, that is, each time the crankshaft rotates 30 °. Specifically, for example, the intake pressure is stored in a shift register as described above, and the intake pressure for each crankshaft 30 ° is read for two rotations of the crankshaft, that is, for one cycle.

Next, proceeding to step S2, it is determined whether or not all the intake pressures read in step S1 are within the normal range in FIG. 9 and whether or not the detected intake pressures are all within the normal range. Proceeds to step S3, otherwise proceeds to step S4.

In step S3, the engine speed calculated by the engine speed calculator 26 is read, and then the process proceeds to step S5.

At step S5, in accordance with the control map shown in FIG Ί Ί, moves after setting the intake pressure variation threshold厶P ₀ corresponding to the engine speed in step S6. In the control map shown in Fig. 1, the intake pressure fluctuation threshold P is increased as the engine speed N increases. Is set to increase linearly.

In step S6, the intake pressure fluctuation value ΔΡ is calculated from the difference between the maximum value and the small value of the intake pressure for two revolutions of the crankshaft read in step S1, and then the process proceeds to step S7.

In step S7, it is determined whether the intake pressure variation value Δ 変動 calculated in step S6 is equal to or less than the intake pressure variation threshold ΔΡ ₀ set in step S5, and the intake pressure variation value ΔΡ is determined as the intake pressure. Pressure fluctuation threshold ΔΡ. If so, the process proceeds to step S8; otherwise, the process proceeds to step S9. In step S9, the intake pressure abnormality counter GNT is cleared to "0", and then the process returns to the main program.

On the other hand, in step S8, the intake pressure abnormality counter is used. After incrementing by 1 \ 11, shift to step S10.

In step S10, the intake pressure abnormality counter CNT is set to a predetermined value CNT. To determine at either above, when the intake pressure abnormality counter CNT is a predetermined value CNT ₀ or more, the routine proceeds to step S4, otherwise, the process returns to the main program.

In step S4, an abnormality is determined according to the individual arithmetic processing performed in the step, and a predetermined fail-safe processing is performed, and then the arithmetic processing ends. This fail-safe processing is performed by, for example, gradually turning on the ignition for each cylinder, gradually shifting the ignition of each cylinder to the retard side, or closing the throttle quickly at first and then slowly. This includes gradually reducing the engine torque or displaying an abnormality.

According to this calculation processing, the intake pressure fluctuation threshold ΔΡ according to the engine speed. The intake pressure fluctuation value Δ 圧力 is calculated in two rotations of the crankshaft, that is, in one cycle, and the intake pressure fluctuation value ΔΡ is the intake pressure fluctuation threshold Δ 閾値. The state below is the specified value. When the above is repeated, it is determined that the intake pressure is abnormal, and the above-described fail-safe processing is performed.ο

Fig. 12 shows the output of the intake pressure sensor when the crankshaft keeps rotating, when the crankshaft engine continues to operate, and when the intake pressure sensor comes off when the crankshaft rotates. . As is apparent from the figure, the output of the sensor when the force of the intake pressure sensor deviates is the value of the atmospheric pressure, and is within the normal output range, that is, the normal range. However, when the output value of the intake pressure sensor becomes << a constant value equivalent to the atmospheric pressure, the intake pressure fluctuation value ΔΡ calculated by the arithmetic processing in FIG. 10 becomes the predetermined value ΔΡ. As described below, it is possible to detect an abnormality.

On the other hand, when the crankshaft rotates, that is, when the engine operates, the intake pressure fluctuation in two rotations of the crankshaft, that is, in one cycle, is larger as the engine speed is larger. small. Therefore, in order to more reliably detect an abnormality in the intake pressure, The intake pressure fluctuation threshold ΔP according to the engine speed. Need to be set. In fact, the intake pressure fluctuation within one cycle is smaller as the throttle opening is larger than just the engine speed. Since the present embodiment has been developed in order to omit the throttle sensor, an intake pressure fluctuation threshold ΔP based on the throttle opening at which a clear throttle opening detection value is obtained. It is possible to estimate the throttle opening from other parameters such as the force omitting the setting of, and the intake pressure fluctuation threshold Δ 応じ according to the estimated throttle opening. May be set. For example, in a steady state, the intake pressure fluctuation in one cycle depends on the engine speed and the throttle opening, and conversely, the throttle opening is estimated from the intake pressure fluctuation and the engine speed in one cycle. can do. Also, since the above-described detection of the acceleration state, that is, the difference from the intake pressure one cycle before the same stroke as the present stroke is the change amount of the throttle opening, the rate of change of the throttle opening during the transition period can be estimated. If the integrated value of the rate of change of the throttle opening in the transition period is added to the throttle opening in the steady state described above, the throttle opening in the transition period can also be estimated.

In the above embodiment, attention is paid to each cylinder, and when one cycle of the cylinder, that is, when the intake pressure fluctuation during the rotation of the crankshaft, is equal to or less than a predetermined value, the intake pressure detecting means such as the intake pressure sensor is abnormal. Since it is sufficient to know the difference between the intake pressures of the intake stroke and the exhaust stroke, for example, in the four-cylinder engine of the embodiment, the intake pressure of the intake stroke and the intake stroke of the exhaust stroke in different cylinders are considered. If the intake pressure difference can be obtained from the pressure, it is not necessary to wait for the crankshaft to make two revolutions. In other words, the intake pressure fluctuation within two revolutions of the crankshaft means the intake pressure variation for two revolutions of the crankshaft at the maximum, and is detected as if the intake pressure detecting means such as the intake pressure sensor came off. As long as the intake pressure can be detected to be constant or almost constant, the intake pressure fluctuation may be detected at any timing.

Further, in this embodiment, only the in-pipe injection type engine has been described in detail. However, the engine control device of the present invention is also applicable to an in-cylinder injection type engine, a so-called direct injection type engine. . However, in a direct injection engine, since fuel does not adhere to the intake pipe, it is not necessary to consider this, and the total amount of injected fuel may be substituted for the calculation of the air-fuel ratio.

In the above-described embodiment, a so-called multi-cylinder engine having four cylinders is used. As described above, the engine control device of the present invention can be similarly applied to a single cylinder engine.

Also, the engine control unit can be replaced with various arithmetic circuits instead of the microcomputer. Industrial potential

As described above, according to the engine control apparatus according to claim 1 of the present invention, the fluctuation force of the intake pressure during the rotation of the crankshaft and within two rotations of the crankshaft << the predetermined value or less In this case, the intake pressure detecting means is configured to detect that the pressure is abnormal, so that, for example, even when the pressure of the intake pressure detecting means such as an intake pressure sensor is deviated and released to the atmosphere, it can be reliably detected. .

Further, according to the engine control device according to claim 2 of the present invention, the smaller the detected engine speed, the smaller the predetermined value of the intake pressure fluctuation for detecting abnormality of the intake pressure detecting means is set. With this configuration, it is possible to reliably detect abnormalities in the layer and the intake pressure detecting means.

Further, according to the engine control device according to claim 3 of the present invention, the larger the detected throttle / opening degree of the throttle is, the more the predetermined value of the intake pressure fluctuation for abnormality detection of the intake pressure detecting means becomes. Since the configuration is set to be small, it is possible to reliably detect abnormalities in the layer and the intake pressure detecting means.

Claims

The scope of the claims

1. Crankshaft phase detecting means for detecting a phase of a crankshaft, intake pressure detecting means for detecting an intake pressure in an intake pipe of an engine, a phase of the crankshaft detected by the crankshaft phase detecting means and the intake air Engine control means for controlling the operating state of the engine based on the intake pressure detected by the pressure detection means; and crankshaft power rotation based on the crankshaft phase detected by the crankshaft phase detection means. And an intake pressure abnormality detecting means for detecting that the intake pressure detecting means is abnormal when the variation of the intake pressure in the crankshaft rotation detected by the intake pressure detecting means is equal to or less than a predetermined value. An engine control device, comprising:

2. An engine speed detecting means for detecting an engine speed, wherein the intake pressure abnormality detecting means sets a predetermined value of the intake pressure fluctuation as the engine speed detected by the engine speed detecting means decreases. The engine control device according to claim 1, wherein the engine control device is set to be small.

3. A throttle opening detecting means for detecting an opening of a throttle valve is provided, and the intake pressure abnormality detecting means detects the intake pressure as the opening of the throttle / knob detected by the throttle opening detecting means increases. 3. The engine control device according to claim 1, wherein a predetermined value of the fluctuation is set to be small.