JP2002030981A - Atmospheric pressure detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an atmospheric pressure detecting device capable of preferably detecting atmospheric pressure without increasing a cost. SOLUTION: An engine 10 is a single cylinder four cycle engine, and repeatedly executes each stroke of intake, compression, explosion, exhaust by opening/ closing an intake valve 21 and an exhaust valve 22. An intake pressure detecting sensor 17 for detecting intake pressure is provided in an intake tube 12 of the engine 10. A CPU 31 in an ECU 30 determines an executing condition for detecting atmospheric pressure on the basis of an engine operating state, by using an engine speed and throttle opening as a parameter. The CPU 31 takes in the intake pressure detected by the intake pressure detecting sensor 17 in the exhaust stroke of the engine 10 when the executing condition for detecting the atmospheric pressure is satisfied, and calculates the atmospheric pressure on the basis of the taken-in intake pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atmospheric pressure detecting device that uses an intake pressure sensor disposed in an engine intake pipe and detects the atmospheric pressure based on a value detected by the intake pressure sensor.

[0002]

2. Description of the Related Art In a vehicle engine, when an on-vehicle electronic control unit (on-vehicle ECU) controls, for example, a fuel injection amount and an ignition timing, an atmospheric pressure is detected and a correction corresponding to the atmospheric pressure is performed. I have. As one method of atmospheric pressure detection,
There is a conventional technique in which an atmospheric pressure sensor is installed in an engine intake pipe or the like, and the atmospheric pressure is detected from the detection result of the sensor. However, in this case, the cost increases due to the installation of the atmospheric pressure sensor, and the system price increases.

As a system in which the atmospheric pressure sensor is abolished, there is a system in which the intake pressure first detected by the intake pressure sensor is taken in as the atmospheric pressure immediately after the engine is started (immediately after the ignition switch is turned on). Further, in this technique, when the engine is running at a low speed and a high load, the intake pressure detected by the intake pressure sensor is updated as the atmospheric pressure. However, in the case of this conventional technique, the atmospheric pressure detection is limited only during the acceleration operation in which the throttle valve is fully opened, and the detection frequency (renewal frequency) is small.
Therefore, there has been a problem that the fuel injection amount and the ignition timing cannot be finely corrected.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to detect the atmospheric pressure appropriately without increasing the cost. An object of the present invention is to provide an atmospheric pressure detecting device.

[0005]

In a four-stroke engine, the intake, compression, explosion, and exhaust strokes are continuously and repeatedly performed. In the intake stroke, engine combustion is performed through an intake pipe by opening an intake valve. Air (mixture) is introduced into the chamber. At this time, the intake pressure (intake pipe pressure) temporarily changes to the negative pressure side from the atmospheric pressure, and gradually returns to the atmospheric pressure side after closing the intake valve (after the intake is completed).
Especially in the case of an engine with an independent intake system for each cylinder,
After the completion of the intake, the intake pressure and the atmospheric pressure substantially coincide until the exhaust stroke immediately before the next intake stroke. The behavior of the intake pressure can also be seen from the time chart shown in FIG. Therefore, in an engine having an independent intake system for each cylinder, the atmospheric pressure can be detected by the detected value (intake pressure) of the intake pressure sensor before or during the exhaust stroke.

In view of the above, according to the first aspect of the present invention, an execution condition of the atmospheric pressure detection based on the operating state of the engine is determined (execution condition determining means). Also, after the intake is completed when the above-described execution conditions are satisfied, the intake pressure detected by the intake pressure sensor is captured at a predetermined time until the next intake stroke, and the atmospheric pressure is obtained based on the captured intake pressure (atmospheric pressure). Detection means).

In short, although the behavior of the intake pressure changes according to the engine operating state, the atmospheric pressure detection is performed while judging the execution condition based on the engine operating state, so that the atmospheric pressure detection can be accurately performed. Become. In this case, with an engine having an independent intake system, the engine operating range where the intake pressure returns to the atmospheric pressure level by the next intake stroke is wide, and the detection timing is mainly compared with the prior art, which is limited to the acceleration operation. , The frequency of the atmospheric pressure detection greatly increases. As a result, the atmospheric pressure can be suitably detected without increasing the cost.

The present invention is preferably applied to a single-cylinder engine or a multi-cylinder engine of an independent intake type, as described in claim 14, and suitable atmospheric pressure detection can be realized in these engines.

According to the present invention, the atmospheric pressure detecting means obtains the atmospheric pressure based on the detected value of the intake pressure in at least one of an explosion stroke and an exhaust stroke of the engine. In this case, in a predetermined engine operating state, the intake pressure in the explosion stroke or the exhaust stroke substantially matches the atmospheric pressure level, so that the atmospheric pressure can be detected.

According to the third aspect of the present invention, the atmospheric pressure detecting means detects the atmospheric pressure based on the detected value of the intake pressure immediately before the intake valve opens. In this configuration, since the intake pressure only needs to return to the atmospheric pressure level at the latest just before the intake stroke, the engine operating region in which the atmospheric pressure can be detected is further widened, and the frequency of the atmospheric pressure detection is further increased. .

In addition, when the intake pressure intake timing is changed according to the engine operating state, it is possible to cope with a wide engine operating state as compared with the case where the intake period is fixed. . In this case, in an operation region where it is relatively difficult to detect the atmospheric pressure, such as during high rotation, the intake pressure intake period is limited to immediately before the next intake stroke. Also,
At the time of low rotation, etc., the intake pressure intake period is lengthened to increase the opportunity for intake pressure intake.

According to the first or second aspect of the present invention, a fifth aspect of the present invention is provided.
As described above, the detected value of the intake pressure during the intake pressure intake period may be averaged to calculate the atmospheric pressure. Alternatively, when the change amount of the intake pressure during the intake pressure intake period exceeds a predetermined value, the detection of the atmospheric pressure may be invalidated. According to the fifth and sixth aspects of the present invention, the detection accuracy of the atmospheric pressure is improved.

According to the present invention, when the atmospheric pressure detecting means detects the present value of the atmospheric pressure, the atmospheric pressure detecting means averages the present value and the atmospheric pressure data stored and held up to that time. The process updates the atmospheric pressure data. In this case, instead of updating the atmospheric pressure data as it is with the atmospheric pressure detected each time, the atmospheric pressure data is updated by performing an averaging process such as a smoothing operation, so that highly reliable atmospheric pressure data can be obtained. Will be obtained.

[0014] The execution condition determining means may be as follows.
It may be realized as follows. That is, Claim 8
According to the invention described in (1), the execution condition is determined based on whether the engine speed and the engine load are in a predetermined operation region as parameters. According to the ninth aspect of the present invention, if the engine load is equal to or higher than a predetermined load level as a parameter,
It is determined that the conditions for performing the atmospheric pressure detection are satisfied. According to the tenth aspect of the present invention, when the vehicle on which the engine is mounted is running at a reduced speed, it is determined that the condition for performing the atmospheric pressure detection is not satisfied.

In any of the above inventions, it is possible to appropriately determine whether or not to perform the atmospheric pressure detection. As the engine load, an opening degree of a throttle valve and an intake pressure provided in an engine intake pipe can be used.

Further, according to the present invention, the difference between the minimum value of the intake pressure detected by the intake pressure sensor and the intake pressure or the average value thereof during the intake pressure intake period for detecting the atmospheric pressure. Is larger than a predetermined value, the atmospheric pressure detection is invalidated. That is, if the difference between the minimum value of the intake pressure and the intake pressure or the average value thereof during the intake pressure intake period is larger than a predetermined value, there is a high possibility that the atmospheric pressure is erroneously detected. Atmospheric pressure is detected.

If unexpected intake pressure fluctuations occur due to backfire or the like, the accuracy of atmospheric pressure detection is significantly reduced.
Therefore, according to the twelfth aspect of the present invention, the maximum value on the positive pressure side is calculated for the detected value of the intake pressure, and when the maximum value exceeds a predetermined value, the detection of the atmospheric pressure by the atmospheric pressure detecting means is prohibited. In the twelfth aspect of the present invention, as described in the thirteenth aspect, when the detected value of the intake pressure exceeds the maximum value on the positive pressure side, it is preferable to prohibit the detection of the atmospheric pressure for a period corresponding to several combustions. According to the twelfth and thirteenth aspects of the present invention, it is possible to avoid the problem that the atmospheric pressure is erroneously detected due to the influence of the intake pressure fluctuation caused by the backfire or the like, and the detection accuracy of the atmospheric pressure is improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, a single-cylinder four-cycle engine mounted on a motorcycle is controlled, and the fuel injection amount and ignition timing of the engine are controlled by an electronic control unit (hereinafter referred to as E).
CU).

FIG. 1 is a block diagram showing the outline of the engine control system. In FIG. 1, an intake pipe 11 is connected to an intake port 11 of an engine 10, and an air box 13 for sucking outside air is connected to an upstream side thereof. The air box 13 is provided with an intake air temperature sensor 14 for detecting the intake air temperature. A throttle valve 15 is attached in the middle of the intake pipe 12, and the opening of the throttle valve 15 (throttle opening) is detected by a throttle opening sensor 16. Further, the throttle valve 15
An intake pressure sensor 17 is provided downstream of the throttle valve, and the intake pressure sensor 17 detects an intake pressure downstream of the throttle valve (intake pipe pressure). A fuel injection valve 18 is attached near the intake port 11, and the fuel injection valve 18 injects fuel (gasoline) supplied from a fuel supply system (not shown) to the intake port 11.

The engine 10 is provided with a reciprocating piston 19 connected to a crankshaft (not shown), and a combustion chamber 20 is formed above the piston 19. The combustion chamber 20 communicates with the intake pipe 12 and the exhaust pipe 23 via the intake valve 21 and the exhaust valve 22. An ignition plug 24 is attached to the cylinder head of the engine 10, and a high voltage generated on the secondary side of the ignition coil 25 is applied to the ignition plug 24 at each ignition timing to ignite.

The crankshaft of the engine 10 is provided with a rotational speed sensor 26 for detecting the engine rotational speed. The rotational speed sensor 26 is provided at every predetermined crank angle (in this embodiment, at every 30 ° CA). A Ne pulse signal is output. Further, the engine 10 is provided with a water temperature sensor 27 for detecting the temperature of the engine cooling water.

The ECU 30 includes a CPU 31, a ROM 32,
The ECU 30 mainly includes a known microcomputer including a RAM 33 and the like. The ECU 30 detects each of the above-described intake air temperature sensor 14, throttle opening sensor 16, intake air pressure sensor 17, rotational speed sensor 26, and water temperature sensor 27. A signal is input. The CPU 31 detects an engine operating state such as an intake air temperature, a throttle opening (TA), an intake pressure (PM), an engine speed (Ne), and an engine water temperature based on each of the detection signals. Further, the CPU 31
By executing a control program or the like stored in the ROM 32 in advance, control of fuel injection by the fuel injection valve 18 and control of ignition timing by the spark plug 24 are appropriately performed.

Further, the apparatus according to the present embodiment is characterized in that the atmospheric pressure is detected based on the intake pressure PM detected by the intake pressure sensor 17, and the details will be described below.

First, an outline that the atmospheric pressure can be detected based on the detection value (intake pressure PM) of the intake pressure sensor 17 will be described with reference to a time chart of FIG. In short, in the intake stroke, the air-fuel mixture is introduced into the combustion chamber 20 by opening the intake valve 21, and the intake pressure at the atmospheric pressure level shifts to the negative pressure side. After the intake pressure reaches the bottom value (minimum value), it gradually changes to the atmospheric pressure side in each of the compression, explosion, and exhaust strokes, and returns to the atmospheric pressure level by the exhaust stroke. At this time, if the engine speed is constant, the bottom value of the intake pressure changes depending on the throttle opening (engine load). As the throttle opening increases, the bottom value of the intake pressure increases (the degree of negative pressure decreases). Conversely, the smaller the throttle opening, the lower the bottom value of the intake pressure (the greater the degree of negative pressure). Further, when the throttle opening changes, the timing at which the intake pressure returns to the atmospheric pressure level is different. Generally, the larger the throttle opening, the quicker the return to the atmospheric pressure level.

In any case, except for an extremely limited engine operating state such as at a high rotation speed and a low load, as shown in FIG. 2, the intake pressure returns to the atmospheric pressure level before or before the exhaust stroke. Thus, the atmospheric pressure can be detected based on the intake pressure. Whether or not the atmospheric pressure can be detected by the intake pressure is determined based on the conditions for performing the atmospheric pressure detection based on the engine operating state.

FIG. 3 is a flowchart showing an atmospheric pressure detection routine.
It is executed every second or in synchronization with the Ne pulse signal of the rotation speed sensor 26. In this process, the exhaust stroke is set as an intake intake period, and a sensor detection value of the intake pressure PM is acquired during the intake period, and the atmospheric pressure is detected based on the PM value. Also,
FIG. 4 is a time chart for supplementarily explaining the flow of the processing.

In the routine shown in FIG. 3, it is necessary to determine which one of the four strokes of intake, compression, explosion, and exhaust is currently in progress. The determination is made based on the Ne pulse signal of the rotation speed sensor 26. Like that. That is, as shown in FIG. 4, for example, a Ne pulse signal is outputted at every 30 ° CA, and the Ne pulse signal is counted, and the process is performed in the order of intake → compression → explosion → exhaust every 6 counts (every 180 ° CA). Is determined to have advanced. In FIG. 4, at times t1 to t
2 is an intake stroke, time t2 to t3 is a compression stroke, and time t3 to
t4 indicates an explosion stroke, and times t4 to t5 indicate an exhaust stroke.

Referring to FIG. 3, first, at step 101, the conditions for detecting the atmospheric pressure are determined based on the engine operating state at that time. At this time, the engine speed Ne
It is determined whether or not the engine operating state is in the atmospheric pressure detection execution area by using a map (not shown) using the parameter and the throttle opening TA as parameters. According to this map, for example, the detection of the atmospheric pressure is prohibited only when the engine 10 is in a state of high rotation and low load (low throttle opening).

If the engine operating state is in the atmospheric pressure detection execution area, step 1 is performed to permit the atmospheric pressure detection.
02 is set to YES, and the subsequent atmospheric pressure detection is performed. If the engine operating state is not in the region where the atmospheric pressure detection is to be performed, NO is set in step 102 to prohibit the atmospheric pressure detection, and the routine ends without performing the subsequent atmospheric pressure detection.

Here, the execution condition of the atmospheric pressure detection may be determined by using the intake pressure PM instead of the throttle opening degree TA. Specifically, the atmospheric pressure detection is performed by the following (1) or (2). Determine the conditions for detection. That is, (1) The minimum value (bottom value) of the intake pressure PM is obtained, and the conditions for performing the atmospheric pressure detection are implemented using the minimum value and the engine speed Ne as parameters. (2) The intake pressure PMav is calculated by statistical processing by taking in several PM values including at least the minimum value of the intake pressure PM or a value in the vicinity thereof, and the intake pressure PMav and the engine speed Ne are used as parameters. Implement the conditions for detecting atmospheric pressure. At this time, the period during which the intake pressure PM is taken in for the load determination is a period during which the intake valve 21 is open or a period until the intake pressure is taken (exhaust stroke).

Thereafter, in step 103, the maximum value PMmax of the intake pressure during the intake-compression stroke period is detected, and in step 104, it is determined whether the maximum value PMmax of the intake pressure has risen to a specified value or more. That is, it is determined whether or not the maximum value PMmax of the intake pressure has changed to the positive pressure side from the predetermined value α with reference to the atmospheric pressure (the detected value). If a backfire or the like has occurred, step 104 becomes YES, and in such a case, this routine ends without detecting the atmospheric pressure.

If YES in step 104 (PMmax> atmospheric pressure + α), the detection of atmospheric pressure is prohibited for a while, and the next step 104 is NO (PMmax
x ≦ atmospheric pressure + α), the determination in step 105 that follows when the predetermined period has elapsed is YES, and the atmospheric pressure detection is restarted. That is, since the intake pressure fluctuation due to the backfire or the like continues for a period corresponding to several combustions, the detection of the atmospheric pressure is prohibited during the period corresponding to the several combustions, and the detection of the atmospheric pressure is restarted after the influence is eliminated.

Referring to FIG. 4, when backfire occurs, for example, the intake pressure PM temporarily increases greatly to the positive pressure side as shown by the two-dot line in the figure, and the PM value becomes "atmospheric pressure +
α ”threshold. In this case, atmospheric pressure detection is prohibited. The detection of the maximum value PMmax of the intake pressure may be performed until immediately before the intake pressure intake period (exhaust stroke).

Thereafter, in step 106, it is determined whether or not the exhaust stroke has been started based on the Ne pulse signal.
If it is S, in the subsequent step 107, the intake pressure sensor 1
7 (the intake pressure PM). In step 108, it is determined whether or not the exhaust stroke has been completed. According to steps 106 to 108, the intake pressure PM is taken in every 30 ° CA during the period from the start to the end of the exhaust stroke (the period immediately before the intake valve 21 is opened). In FIG. 4, during the period from time t4 to t5, the intake pressure PM has substantially converged to the atmospheric pressure level, and during this period, the intake pressure PM is taken in.

Thereafter, in step 109, it is determined whether or not the difference ΔPM between the maximum value and the minimum value of the intake pressure PM during the intake pressure intake period (exhaust stroke) is less than a predetermined value β.
When ΔPM ≧ β, that is, when the fluctuation of the intake pressure PM in the exhaust stroke is relatively large, the routine ends without updating the atmospheric pressure.

If ΔPM <β, step 110
Then, the atmospheric pressure is detected by averaging the taken intake pressure PM, and if the current detected value is different from the previous detected value, the atmospheric pressure is updated based on the current detected value. At this time, it is desirable to update (increase / decrease) the atmospheric pressure while performing the smoothing process. For example, as a method, a predetermined value is added or subtracted from the previous value, or the difference between the previous value and the current value is calculated. "1 / n" (n is a natural number) is added to or subtracted from the previous value, or the detected value for a predetermined period (for example, 1 second) is averaged. However, it is also possible to update the current value as it is as the atmospheric pressure data without performing the averaging process.

In this embodiment, step 1 in FIG.
01 and 102 correspond to the execution condition determining means of the present invention, and steps 106 to 108 and 110 correspond to the atmospheric pressure detecting means.

Next, how the atmospheric pressure is detected immediately after the start of the engine will be described with reference to the time chart of FIG. When the ignition switch is turned on at time t11 and power is supplied to the ECU 30, the atmospheric pressure is detected from the detected value of the intake pressure sensor 17 at that time. After that, the engine 10 is started by cranking and the engine speed (for example, 1500 rpm of the idle speed)
When m) reaches a predetermined value, atmospheric pressure detection is permitted (time t12). Incidentally, during the cranking period immediately after the engine is started, the atmospheric pressure detection is not performed because there is a possibility of being affected by noise from a starter relay or the like.

The period from time t12 to t13 is during idling and acceleration operation, and the period from time t13 to t14 is during steady operation,
In these cases, the conditions for implementing atmospheric pressure detection (predetermined operating conditions)
Is satisfied, and atmospheric pressure detection is performed.

At time t14, the throttle valve 15 is closed, and thereafter, the vehicle starts to run at a reduced speed. At this time, at time t15
When the throttle opening is almost fully closed in, the engine operating state shifts to a state of high rotation and low load (low throttle opening), and the conditions for implementing atmospheric pressure detection are not satisfied.
Atmospheric pressure detection is prohibited. Thereafter, when the engine speed falls and the engine operating state shifts to a low rotation / low load (low throttle opening) state, atmospheric pressure detection is permitted and restarted (time t16).

According to the embodiment described above, the following effects can be obtained. (A) When the conditions for implementing atmospheric pressure detection based on the engine operating condition are satisfied, the atmospheric pressure is obtained based on the intake pressure PM in the exhaust stroke of the engine 10. Therefore, the atmospheric pressure is obtained without increasing the cost. Can be suitably detected. In this case, in the single-cylinder engine, the engine operation range in which the intake pressure PM returns to the atmospheric pressure level by the next intake stroke is considerably wide, and the detection timing is large compared to the prior art in which the detection timing is mainly limited to the acceleration operation. The frequency of atmospheric pressure detection greatly increases. In addition, since the frequency of updating the atmospheric pressure increases, fine correction of the fuel injection amount and the ignition timing can be realized.

(B) The intake pressure PM during the intake pressure intake period (exhaust stroke) for detecting the atmospheric pressure is averaged to calculate the atmospheric pressure, and when the PM is acquired, the amount of change in the intake pressure (the maximum value and the maximum value). If the minimum value difference ΔPM) exceeds a predetermined value, the detection of the atmospheric pressure is invalidated, so that the detection accuracy of the atmospheric pressure is improved.

(C) Since the previous detection value of the atmospheric pressure is updated while performing the averaging process such as the smoothing operation, even if there is a temporary erroneous detection, its influence is eliminated and the reliability is high. Atmospheric pressure data can be obtained.

(D) calculating the maximum value PMmax of the intake pressure, prohibiting the detection of the atmospheric pressure if the PMmax exceeds a predetermined value, and restarting the detection of the atmospheric pressure after the lapse of a predetermined period corresponding to several combustions; did. According to this, even when the intake pressure fluctuates due to a backfire or the like, a problem that the atmospheric pressure is erroneously detected due to the influence is avoided, and the detection accuracy of the atmospheric pressure is improved.

The present invention can be embodied in the following modes other than the above. In the above embodiment, in the process of FIG. 3, the intake pressure PM is taken in the exhaust stroke, and the intake pressure P
Although the atmospheric pressure is detected based on M (step 106 and subsequent steps), this is changed as follows.

(1) The atmospheric pressure is detected based on the intake pressure PM immediately before the intake valve 21 opens. Actually, for example, the intake pressure PM is taken in at the timing of P1 in FIG. 4, and the atmospheric pressure is detected based on the intake pressure PM. In this case, since it is sufficient that the intake pressure has returned to the atmospheric pressure level at least immediately before the intake stroke, the engine operating region in which the atmospheric pressure can be detected is further widened, and the frequency of the atmospheric pressure detection is further increased.

(2) The intake time of the intake pressure PM is extended to a period including not only the exhaust stroke but also the immediately preceding explosion stroke (the entire period or a part of the explosion stroke), and the intake air taken in the period is included. The atmospheric pressure is detected based on the atmospheric pressure PM. Alternatively, instead of the exhaust stroke, the intake pressure PM is taken in the explosion stroke (the entire period or a part of the explosion stroke), and the atmospheric pressure is detected based on the intake pressure PM.

(3) The intake pressure PM intake time is extended to a period including the latter half of the compression stroke, and the atmospheric pressure is detected based on the intake pressure PM acquired in the period. In the above cases (2) and (3), it is assumed that the intake pressure PM has converged to the atmospheric pressure level during a period including the explosion stroke or the compression stroke, and the conditions for performing the atmospheric pressure detection are set so that the preconditions are satisfied. (Engine operating state) is changed.

(4) The intake timing of the intake pressure PM is changed according to the operating state of the engine. For example, in an operation region where it is relatively difficult to detect the atmospheric pressure, such as at a high speed, the intake pressure P
The intake timing of M is delayed so that it is limited to just before the intake stroke.
Conversely, when the engine speed is low or when the load is high, the intake pressure PM intake timing is advanced, and the intake pressure intake period is lengthened.

In any case, it is sufficient that the intake pressure PM is taken at a predetermined time after the completion of the intake and before the next intake stroke, and the atmospheric pressure is obtained based on the taken intake pressure. Incidentally, in an engine having a variable valve timing mechanism (VVT mechanism), the intake pressure intake period may be changed according to the VVT drive amount.

Atmospheric pressure detection execution condition determination (FIG. 3, steps 101 and 102): Atmospheric pressure detection execution conditions are determined using only the engine load such as throttle opening TA and intake pressure PM as parameters.
If these are at or above the predetermined load level, it is determined that the conditions for performing the atmospheric pressure detection are satisfied. It is determined whether or not the vehicle is running at a reduced speed, and at the time of running at a reduced speed, it is determined that the condition for performing the atmospheric pressure detection is not satisfied. Such a configuration may be adopted.

When the difference between the minimum value of the intake pressure PM and the average value of the intake pressure PM (or the intake pressure PM itself) during the intake pressure intake period (exhaust stroke or the like) is larger than a predetermined value, the atmospheric pressure detection is performed. Invalidate. Thereby, erroneous detection of the atmospheric pressure can be prevented.

In the above embodiment, the present invention is embodied in a motorcycle having a single cylinder engine. However, the present invention is not limited to this and may be embodied in other ways. For example, the present invention can be applied to an independent intake type multi-cylinder engine. In the case of a multi-cylinder engine, the intake pressure of a specific cylinder is detected, and the atmospheric pressure is detected based on the intake pressure. Or a single cylinder engine,
Alternatively, the present invention may be embodied in an automobile having an independent intake type multi-cylinder engine.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of an engine control device according to an embodiment of the present invention.

FIG. 2 is a time chart showing the behavior of intake pressure in each stroke.

FIG. 3 is a flowchart illustrating an atmospheric pressure detection routine.

FIG. 4 is a time chart showing the behavior of the intake pressure in each stroke.

FIG. 5 is a time chart showing how atmospheric pressure is detected from the time of starting the engine.

[Explanation of symbols]

10 engine, 12 intake pipe, 17 intake pressure sensor
Reference numeral 21: intake valve, 22: exhaust valve, 30: ECU, 31: C
PU.

Claims (14)

[Claims] An intake, compression, explosion, and exhaust stroke is repeatedly performed by opening and closing an intake valve and an exhaust valve, and is applied to a four-stroke engine having an independent intake system for each cylinder. An intake pressure sensor for detecting an intake pressure, an implementation condition determining means for determining an implementation condition of atmospheric pressure detection based on an engine operating state, and a predetermined time from completion of intake when the implementation condition is satisfied until the next intake stroke. An atmospheric pressure detecting device which takes in the intake pressure detected by the intake pressure sensor at the time of, and obtains an atmospheric pressure based on the taken intake pressure. 2. The atmospheric pressure detecting device according to claim 1, wherein said atmospheric pressure detecting means obtains an atmospheric pressure based on a detected value of an intake pressure in at least one of an explosion stroke and an exhaust stroke of the engine. 3. The atmospheric pressure detecting device according to claim 1, wherein said atmospheric pressure detecting means detects an atmospheric pressure based on a detected value of an intake pressure immediately before an intake valve opens. 4. The atmospheric pressure detecting device according to claim 1, wherein the intake pressure intake timing is changed according to an engine operating state. 5. The atmospheric pressure detecting device according to claim 1, wherein said atmospheric pressure detecting means calculates an atmospheric pressure by averaging a detected value of the intake pressure during an intake pressure capturing period. 6. The atmospheric pressure detection device according to claim 1, wherein the atmospheric pressure detection is invalidated when the amount of change in the intake pressure during the intake pressure intake period exceeds a predetermined value. 7. The atmospheric pressure detecting means, when detecting the current value of the atmospheric pressure, updates the atmospheric pressure data by averaging the current value and the atmospheric pressure data stored and held up to that time. The atmospheric pressure detecting device according to claim 1. 8. The atmospheric pressure detecting device according to claim 1, wherein said execution condition determining means determines the execution condition based on whether or not the engine is in a predetermined operation region using the engine speed and the engine load as parameters. . 9. The execution condition determining means determines that the execution condition of the atmospheric pressure detection is satisfied when the engine load is at or above a predetermined load level using the engine load as a parameter.
The atmospheric pressure detecting device according to any one of the above. 10. The method according to claim 1, wherein the execution condition determining means determines that the execution condition of the atmospheric pressure detection is not satisfied when the vehicle equipped with the engine is running at a reduced speed. Atmospheric pressure detector. 11. When the difference between the minimum value of the intake pressure detected by the intake pressure sensor and the intake pressure or the average value thereof during the intake pressure intake period for detecting atmospheric pressure is larger than a predetermined value, The atmospheric pressure detecting device according to any one of claims 1 to 10, wherein the atmospheric pressure detection is invalidated. 12. The method according to claim 1, wherein a maximum value on the positive pressure side is calculated for the detected value of the intake pressure, and when the maximum value exceeds a predetermined value, the detection of the atmospheric pressure by the atmospheric pressure detecting means is prohibited. An atmospheric pressure detection device according to any one of the above. 13. The atmospheric pressure detecting device according to claim 12, wherein when the detected value of the intake pressure exceeds the maximum value on the positive pressure side, the atmospheric pressure detection is prohibited for a period corresponding to several combustions. apparatus. 14. The atmospheric pressure detecting device according to claim 1, which is applied to a single cylinder engine or a multi-cylinder engine of an independent intake type.