WO2004013477A1

WO2004013477A1 - Engine control device

Info

Publication number: WO2004013477A1
Application number: PCT/JP2003/004663
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: AU2003236225A1; TW200403388A; TWI222492B

Abstract

An engine control device capable of surely detecting the abnormality of crank pulses by detecting also abnormalities caused when the cable of a crank angle sensor is broken, wherein when the crank pulses cannot be detected for a specified time or longer, the varied value ΔP of the intake pressure of a 4-stroke cycle engine is calculated for two or more rotations of the crankshaft of the engine, i.e., one or more cycles of the engine and, a state where the varied value ΔP of the intake pressure is above a threshold ΔP0 or higher is continued for a specified value CNT0 or longer, the crank pulses are determined to be abnormal, and since the varied value ΔP of the intake pressure is smaller as the engine speed is lower and a throttle opening is larger, the abnormality of the crank pulses can be more surely detected by setting the threshold ΔP0 to a value slightly smaller than the minimum value of the varied value ΔP of the intake pressure.

Description

Specification

Engine control equipment 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 becomes easier to control the timing of fuel injection and the amount of injected fuel, that is, the air-fuel ratio, and to promote higher output, lower fuel consumption, and cleaner exhaust gas. You can now. Of these, particularly regarding 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 camshaft, and to inject fuel accordingly. However, a so-called force sensor for detecting the phase state of the camshaft is expensive, and cannot be adopted particularly in a motorcycle or the like due to a problem such as a large cylinder head. Therefore, for example, Japanese Patent Application Laid-Open No. 10-227252 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 a stroke state without detecting the phase of the camshaft, and it is possible to control the fuel injection timing and the like in accordance with the stroke state. .

By the way, the phase of the crankshaft is determined by, for example, forming a claw on the outer periphery of the crankshaft itself or a member that rotates synchronously with the crankshaft, and detecting a state of movement of the claw by a crankshaft phase detecting means such as a magnetic sensor. However, for example, when the crankshaft phase detecting means such as the magnetic sensor is in an abnormal state such as disconnection and the output value becomes a constant value, in the conventional engine control device having no cam sensor, the engine power is stopped. Therefore, it is impossible to determine whether the crankshaft phase detecting means cannot detect the phase of the crankshaft or whether the phase of the crankshaft cannot be detected due to an abnormal state such as the disconnection described above. . In other words, simply detecting the phase of the crankshaft is not enough. An abnormality of the stage cannot be detected.

The present invention has been developed to solve the above problems, and has as its object to provide an engine control device capable of reliably detecting an abnormality of a crankshaft phase detecting means. Disclosure of the invention

Thus, the engine control device 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 a crankshaft phase detecting means. Engine control means for controlling the operating state of the engine based on the detected crankshaft phase and the intake pressure detected by the intake pressure detection means, and the crankshaft phase detection means detecting the crankshaft phase. And a crankshaft phase abnormality detecting means for detecting that the crankshaft phase detecting means is abnormal when the fluctuation of the intake pressure within a predetermined time detected by the intake pressure detecting means is a predetermined value or more. It is characterized by having. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic configuration diagram of a motorcycle engine and its control device. FIG. 2 is an explanatory diagram of the principle of transmitting a crank pulse in the engine of FIG. 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 intake pressure.

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

FIG. 8 is a flowchart showing calculation processing of intake pressure abnormality detection performed by the engine control unit of FIG.

FIG. 9 is a control map used in the calculation processing of FIG. FIG. 10 is an explanatory diagram of an intake pressure signal when the crank angle sensor is disconnected. 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 automatic pie and a control device thereof. 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, and a spark plug 10 And an ignition coil 11. Further, a throttle valve 12 which is opened and closed according to the opening degree of the accelerator is provided in the intake pipe 6, and an intake pipe 6 as a fuel injection device is provided in the intake pipe 6 downstream of the throttle valve 12. 13 is provided. The indicator 13 is connected to a filter 18, a fuel pump 17, and a pressure control valve 16 provided in a fuel tank 19. The engine 1 is a so-called independent intake system, and the injectors 13 are provided in each intake pipe 6 of each cylinder. The operating state of the engine "I" is controlled by an engine control unit 15. The control input of the engine control unit 15, that is, the rotation angle of the crankshaft 3, That is, a crank angle sensor 20 for detecting the phase, a temperature of the cylinder body 2 or a coolant temperature, that is, a coolant temperature sensor 21 for detecting the temperature of the engine body, and an exhaust air-fuel ratio for detecting an air-fuel ratio in the exhaust pipe 8. A sensor 22, an intake pressure sensor 24 for detecting an intake pressure in the intake pipe 6, and an intake temperature sensor 25 for detecting a temperature in the intake pipe 6, that is, an intake temperature, are provided. 5 inputs the detection signals of these sensors, the fuel pump 17, pressure control valve 16, injector 13, ignition Outputs a control signal to yl 1 1.

Here, the principle of the crank angle signal output from the crank angle sensor 20 will be described. In the present 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. The pulse signal is sent out after the electrical processing. 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. As 1 0 ° I do. However, only one portion does not follow this pitch, and there are portions where the pitch is twice as large as the pitch of the other teeth 23. As shown by the two-dot chain line in FIG. 2a, it is originally a special setting where there is no tooth at the toothed portion, and this portion corresponds to unequal spacing. Hereinafter, this portion is also referred to as a toothless portion.

Accordingly, the pulse signal train of each tooth 23 when the crankshaft 3 is rotating at a constant speed appears as shown in FIG. 2B. FIG. 2a shows a state at the time of compression top dead center (the same applies to the form of exhaust top dead center). The pulse signal immediately before the compression top dead center is shown as "0", The next pulse signal is numbered ("1"), the next pulse signal is numbered "2", and so on. Since the tooth 23 corresponding to the pulse signal of "4" shown in the figure is a tooth missing portion, it is counted as an extra tooth as if the tooth is present, and the pulse signal of the next tooth 23 is shown in the figure "6". Numbered. When this is repeated, the missing portion of the tooth approaches the pulse signal of "16" shown in the figure, so one extra tooth is counted in the same manner as described above, and the pulse signal of the next tooth 23 is added. Are numbered "18" in the illustration. When the crankshaft 3 makes two rotations, all four stroke cycles are completed. When the numbering is completed up to “23” in the figure, the pulse signal of the next tooth 23 is numbered again as “0” in the figure. In principle, the compression top dead center should be immediately after the pulse signal of the tooth 23 numbered “0” in the figure. Thus, the detected pulse signal train or a single pulse signal thereof is defined as a crank pulse. When the stroke detection is performed based on the crank pulse as described later, the crank timing can be detected. Note that the teeth 23 are exactly the same even if they are provided on the outer periphery of a member that rotates synchronously with the crankshaft 3.

On the other hand, the engine control unit 15 is constituted by a microcomputer (not shown) or the like. FIG. 3 is a block diagram showing an embodiment of the engine control arithmetic processing performed by the microcomputer in the engine control unit 15. In this calculation process, an engine speed calculating section 26 for calculating an engine speed from the crank angle signal, and a crank timing detecting section for detecting the crank angle signal and the intake pressure signal power and crank timing information, that is, the stroke state, are also provided. 27, and read the crank timing information detected by the crank timing detecting section 27 to calculate an intake air amount from the intake air temperature signal and the intake air pressure signal. An air amount calculation unit 28, a target air-fuel ratio is set based on the engine speed calculated by the engine speed calculation unit 26 and the intake air amount calculated by the intake air amount calculation unit 28, and the acceleration state is determined. The fuel injection amount setting unit 29 for calculating and setting the fuel injection amount and the fuel injection timing by detecting the fuel injection amount and the crank timing information detected by the crank timing detection unit 27 is read, and the fuel injection amount setting unit 29 is read. The injection pulse output unit 30 that outputs an injection pulse corresponding to the fuel injection amount and fuel injection timing set in the above to the injector 13 and the crank timing information detected by the crank timing detection unit 27 are read. The ignition timing is set 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. The ignition timing setting unit 31 reads the crank timing information detected by the crank timing detection unit 27, and sends an ignition pulse corresponding to the ignition timing set by the ignition timing setting unit 31 to the ignition coil 11. It comprises a firing pulse output unit 32 for outputting.

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

The crank timing detecting section 27 has the same configuration as the stroke discriminating apparatus described in Japanese Patent Application Laid-Open No. H10-227252, and thereby detects the stroke state of each cylinder as shown in FIG. 4, for example. And outputs it as crank timing information. That is, in a four-cycle engine, the crankshaft and the camshaft are constantly rotating with a predetermined phase difference, so that, for example, when a crank pulse is read as shown in FIG. The fourth "9" or "21" crank pulse shown is either the exhaust stroke or the compression stroke. As is well known, the exhaust valve opens during the exhaust stroke and the intake pressure is high because the intake valve is closed.At the beginning of the compression stroke, the intake pressure is low because the intake valve is still open or the intake valve is low. Even if it is closed, the intake pressure is low in the preceding intake stroke. Therefore, when the intake pressure is low, the crank pulse shown in "21" indicates that the compressor is in the compression stroke. Immediately after the indicated crank pulse is obtained, the compression top dead center is reached. In this way, if any stroke state can be detected, the current stroke state can be detected more finely by interpolating between the strokes with the rotation speed of the crankshaft. If the stroke of any one of the cylinders can be detected in this way, 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 detected naturally.

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

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 valve closing timing. That is, when the intake valve is opened, the intake pressure and the in-cylinder pressure are substantially equal, and therefore, the in-cylinder air mass can be obtained if the intake pressure, the in-cylinder volume, and the intake temperature are known. However, since the intake valve is open for a while after the start of the compression stroke, air flows in and out of the cylinder and the intake pipe during this time, and the intake air amount calculated from the intake pressure before bottom dead center is actually May be different from the amount of air drawn into the cylinder. Therefore, even when the intake valve is opened, air does not flow in and out of the cylinder and the intake pipe, and the intake air amount is calculated using the intake pressure in the compression stroke. In addition, in order to further strictly consider, the influence of the burned gas partial pressure may be taken into consideration, and the correction may be made according to the engine rotation speed obtained by an experiment using the engine rotation speed having a high correlation with the burned gas partial pressure.

Further, in the present embodiment, an independent intake system, mass flow map for the intake air quantity calculation, as shown in FIG. 6, and _(this is used as a relatively linear relationship between the intake pressure, obtaining Air mass is based on Boyle-Charles law (PV = nRT) It is. On the other hand, when the intake pipe is connected to all cylinders, the assumption of intake pressure and cylinder pressure cannot be established due to the influence of the pressure of the other cylinders. Must be used.

The fuel injection amount setting unit 29 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. Based on 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, the steady-state fuel injection amount and the fuel injection timing are calculated. A steady-state fuel injection amount calculation unit 34, a fuel behavior model 35 used for calculating the steady-state fuel injection amount and the fuel injection time by the steady-state fuel injection amount calculation unit 34, the crank angle signal and the intake Acceleration state detection means 41 for detecting an acceleration state based on the pressure signal and the crank timing information detected by the crank timing detection section 27, and an acceleration state detected by the acceleration state detection means 41 Engine and a time acceleration fuel injection quantity calculating section 42 for calculating the acceleration fuel injection quantity and fuel injection timing according to the engine speed calculated by the speed calculating unit 26. 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, in the present embodiment in which the injection in the intake pipe is performed, it is not possible to accurately calculate and set the fuel injection amount and the fuel injection timing. 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, the amount of fuel injected into the intake pipe 6 from the injector ₁ 3 M _F _ _1NJ, of which the fuel adhesion rate adhering to the intake pipe 6 walls X Then, the fuel injection amount M _F _ _INJ of among the direct inflow quantity directly injected into the cylinder is _{((1 -X) XM F.} INJ) , and the adhesion amount of adhering to the intake pipe wall becomes (XXM _MNJ). Some of the deposited fuel flows into the cylinder along the intake pipe wall. Assuming that the remaining amount is the fuel residual amount M _F — _BUF , the carry-out rate of the fuel residual amount M _F — _BUF taken away by the intake air flow is τ. amount (XM _F Te - _BUF) becomes.

Therefore, in the steady-state fuel injection amount calculating portion 34, firstly the cold from the cooling water temperature T _w The cooling water temperature correction coefficient K _w is calculated using the cooling water temperature correction coefficient table. Meanwhile, the relative amount of intake air M _A _ _MAN, for example, performs a fuel cut routine that Bokusu cutlet fuel when the throttle opening is zero, the temperature-corrected then using the intake air temperature T _A air Calculate the inflow amount M _A and add the target air-fuel ratio AF to the calculated value. 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, the E emission Jin rotational speed N _E and the intake air pressure P _A _ _MAN with obtaining the fuel adhesion rate X by using the fuel deposition rate map, also the engine speed N _E and the intake air pressure P _A _ kingdom Then, the carry-out rate τ is calculated using the carry-out rate map. Then, by multiplying the carry-off ratio τ in the fuel residual quantity M _F _ _BUF obtained in the previous operation to calculate the fuel take-away amount M _F _ _TA, the fuel subtracting it from the required fuel inflow amount M _F to calculate the direct inflow M _F _ _DIR. As described above, the fuel direct inflow quantity M _F - _DIR, said because it is (1-X) times the fuel injection quantity MF, where (1-X) with dividing by the steady-state fuel injection amount M _F _ _{Calculate 1NJ} . Also, among the fuel residual quantity M _F _ _BUF remaining in the intake pipe up to the previous time, - for _{((l r) M F _} BUF) remains Once again, the fuel adhesion amount to (XXM _F _ _1NJ ) to sum, and this time of the fuel residual quantity M _F _ _BUF.

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 before entering the explosion (expansion) stroke or at the beginning of the compression stroke following it. Therefore, 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 previous cycle according to the intake air amount.

Further, the acceleration state detection section 41 has an acceleration state threshold value table. This is obtained 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 present intake pressure, from the intake pressure signal, and calculating the value. Is a threshold value for detecting that the vehicle is in the accelerating state by comparing with a predetermined value, and specifically differs for each crank angle. Accordingly, the acceleration state is detected by comparing a difference value of the intake pressure with the previous value with a predetermined value different at each crank angle. The detection of the acceleration state, also _c performed from the detection of the previous acceleration state after the predetermined cycle elapses, the acceleration fuel injection quantity calculating unit 42 when the acceleration state by the acceleration state detecting section 41 is detected The difference between the current value and the previous value of the intake pressure, and the engine The acceleration fuel injection quantity M _F _ _ACC corresponding to the emission rpm N _E is calculated from the three-dimensional map. In the present embodiment, the fuel injection timing during 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} Shall be injected.

The ignition timing setting unit 31 calculates a basic ignition timing for calculating 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 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. _c the basic ignition timing calculation unit 36 configured with the door includes a current engine speed, the target air-fuel ratio at that time determined by such map searching ignition timing is most generated torque becomes large, the basic ignition timing Is calculated as In other words, the basic ignition timing calculated by the basic ignition timing calculation unit 36 is based on the result of the intake stroke of the immediately preceding cycle, similarly to the steady-state fuel injection amount calculation unit 34. In addition, the ignition timing correction unit 38 determines whether the acceleration fuel injection amount is added to the steady-state fuel injection amount in accordance with the acceleration fuel injection amount calculated by the acceleration fuel injection amount calculation unit 42. When the air-fuel ratio in the cylinder is determined and the air-fuel ratio in the cylinder is significantly different from the target air-fuel ratio set by the target air-fuel ratio at steady state calculation section 33, the air-fuel ratio in the cylinder, the engine speed, and the intake pressure are used. The ignition timing is corrected by setting a new ignition timing.

As described above, the engine control device according to the present embodiment can appropriately control the operating state of the engine using the intake pressure and the crank pulse without using the cam sensor and the throttle sensor. When the engine is stopped, no crank pulse is generated because the crankshaft is not rotating. Of course, the crank angle sensor 20 including a magnetic sensor does not output the crank pulse. When the crank angle sensor 20 composed of the magnetic sensor and the like is in an abnormal state such as disconnection, it does not output a crank pulse. The abnormality of the sensor 20, that is, the crank phase detecting means cannot be detected.

Therefore, in the engine control unit 15, abnormality of the intake pressure sensor is detected by a calculation process shown in FIG. This calculation process is, for example, about 1 Omsec. Is performed by a timer interrupt process at every predetermined sampling time ΔΤ set in. Further, in this operation processing, no step for communication is particularly provided, but information necessary for the operation is read as needed, and the result of the operation is stored as needed.

In this calculation process, it is first determined in step S1 whether a crank pulse cannot be detected. If a crank pulse cannot be detected, the process proceeds to step S2. If not, the process proceeds to step S3.

In step S2, it is determined whether a crank pulse cannot be detected for a predetermined time or more.If the crank pulse cannot be detected for a predetermined time, the process proceeds to step S4. Move to step S3.

In step S3, the intake pressure is read at predetermined time intervals at least for a predetermined time period corresponding to at least two rotations of the crankshaft, and then the process proceeds to step S5.

In the step S5, it is determined whether or not all the intake pressures read in the step S4 are within the normal range in FIG. 9 .If all the detected intake pressures are within the normal range, the process proceeds to step S6. If not, go to step S7. The normal region indicates, for example, an output region excluding the vicinity of the upper limit value and the vicinity of the lower limit value of the output value of the intake pressure sensor.

In step S7, the intake pressure 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 means that the engine torque is gradually reduced by, for example, gradually thinning out the ignition for each cylinder, gradually shifting the ignition of each cylinder to the retard side, or increasing the speed of the throttle first and then closing it slowly. Or display an abnormal display.

On the other hand, in step S6, the intake pressure fluctuation value Δ 算出 is calculated from the difference between the maximum value and the minimum value of the intake pressure read in step S4, and the process proceeds to step S8.

In the step S8, the intake pressure variation value ΔΡ calculated in the step S6 is a preset intake pressure variation threshold ΔΡ. It is determined whether or not this is the case, and the intake pressure variation value ΔΡ is determined as the intake pressure variation threshold value ΔΡ. If so, the process proceeds to step S9; otherwise, the process proceeds to step S3. At the step S3, the crank pulse abnormality counter CNT is cleared to "0" [0], and the process returns to the main program.

On the other hand, in step S9, the crank pulse abnormality counter CNT is incremented, and the process proceeds to step S10.

In step S10, the crank pulse abnormality counter CNT is set to a predetermined value CNT. It is determined whether or not the above is satisfied, and the crank pulse abnormality counter CNT reaches the predetermined value CNT. If so, the process proceeds to step S11. Otherwise, the process returns to the main program.

In the step S11, the crank pulse 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 is ended. In the fail-safe process, for example, the ignition is gradually thinned out for each cylinder, the ignition of each cylinder is gradually shifted to the retard side, or the throttle is initially fast and then the same as when the intake pressure abnormality is determined. For example, the engine torque is gradually reduced by closing slowly, or an abnormality is displayed.

According to this calculation processing, the intake pressure fluctuation value Δ の over two rotations of the crankshaft, that is, one cycle or more, is calculated, and this intake pressure fluctuation value Δ Ρ is set to a preset intake pressure fluctuation threshold Δ Ρ. The above condition is the predetermined value CNT. When the above is repeated, it is determined that the crank pulse is abnormal, and the above-described fail-safe processing is performed.

Fig. 11 shows the output of the intake pressure sensor and the output of the crank angle sensor when the crankshaft continues to rotate, that is, when the crank angle sensor is in an abnormal state such as disconnection while the engine is running. It is shown. As apparent from the figure, when the crank angle sensor is in an abnormal state such as disconnection, the crank pulse is not detected. However, as long as the engine continues to operate, the intake pressure fluctuates as described above. Therefore, when the crank pulse is not detected for a predetermined time or more, the intake pressure for two revolutions of the crankshaft, that is, for one cycle or more, is detected, and the difference between the maximum value and the minimum value, that is, the intake pressure fluctuation value ΔΡ is calculated. Then, the intake pressure fluctuation value ΔΡ is a threshold value ΔΡ. When this is the case, it can be determined that some abnormality has occurred in the crank angle sensor.

By the way, when the crankshaft is rotating, that is, when the engine is running. The intake air pressure fluctuation within two revolutions of the crankshaft, that is, within one cycle, is smaller as the engine speed is smaller, and smaller as the throttle opening is larger. Therefore, in order to more reliably detect the crank pulse abnormality, the intake pressure fluctuation threshold Δ より is set to a value slightly smaller than the minimum value of the actually generated intake pressure fluctuation. Should be set to. In this embodiment, only the intake pipe injection type engine is described in detail. However, the engine control device of the present invention can be applied to an in-cylinder injection type engine, a so-called direct injection type engine. However, in a direct injection type engine, fuel does not adhere to the intake pipe. Therefore, it is not necessary to consider this. For calculating the air-fuel ratio, the total amount of injected fuel may be substituted.

In the above-described embodiment, a so-called multi-cylinder engine having four cylinders has been described in detail. However, 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 by various arithmetic circuits instead of the microcomputer. Industrial potential

As described above, according to the engine control apparatus of the present invention, the crankshaft phase detecting means does not detect the phase of the crankshaft, and the fluctuation of the intake pressure within the predetermined time detected by the intake pressure detecting means. The crankshaft phase detection means such as a magnetic sensor is in an abnormal state, such as a disconnection, so that the output value becomes a constant value when the crankshaft phase detection means is abnormal when the value is equal to or more than a predetermined value. Even when the error occurs, the abnormality can be reliably detected.

Claims

The scope of the claims

1. Crankshaft phase detection means for detecting the phase of the crankshaft, intake pressure detection means for detecting the intake pressure in the intake pipe of the engine, and the phase of the crankshaft detected by the crankshaft phase detection means and the intake air An engine control means for controlling the operating state of the engine based on the intake pressure detected by the pressure detection means; and a crankshaft phase detection means which does not detect the phase of the crankshaft and the intake pressure detection means An engine control device comprising: crankshaft phase abnormality detecting means for detecting that the crankshaft phase detecting means is abnormal when the detected fluctuation of the intake pressure within a predetermined time is equal to or more than a predetermined value. .