JP2005009448A - Atmospheric-pressure detection device of multi-cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly detect atmospheric-pressure on the basis of intake pressure detected for each cylinder in consideration of difference in behaviors of respective cylinders in a multi-cylinder internal combustion engine of an individual-intake system. <P>SOLUTION: When execution conditions are established for atmospheric-pressure detection corresponding to operation conditions of the multi-cylinder internal combustion engine 1 comprising two cylinders of individual-intake system, atmospheric-pressure estimates are computed on the basis of intake pressures PM1, PM2 which are detected by intake-pressure sensors 22, 22' and input at every specified timing in a specified period in a combustion cycle of every cylinder. When deviation of the computed atmospheric-pressure estimate falls in a specified range, the mean of the estimates is set as the atmospheric pressure. Thus, while maintaining the calculation accuracy in computing atmospheric-pressure estimate, the renewal frequency can be increased. Reliability of the finally set atmospheric-pressure is improved, and the operation condition of the engine 1 can be well maintained, because a fine and accurate correction can be made e.g. to fuel-injection quantity, ignition timing, etc. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an atmospheric pressure detection device for a multi-cylinder internal combustion engine that detects an atmospheric pressure of an ambient environment based on a detected value of an intake pressure in an intake passage for each cylinder of an independent intake multi-cylinder internal combustion engine. Knowing the fluctuation can be reflected in the fuel injection amount supplied to each cylinder of the multi-cylinder internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, it is known to maintain an operating state of an internal combustion engine satisfactorily by detecting the atmospheric pressure in the environment surrounding the internal combustion engine and correcting the fuel injection amount according to the atmospheric pressure, for example. At this time, in the system in which the atmospheric pressure sensor is arranged and the atmospheric pressure is detected from the detection result, there is a problem that the cost increase is unavoidable and the price of the entire system is increased.
[0003]
As what copes with this, what was disclosed by Unexamined-Japanese-Patent No. 2002-30981 is known. This technique shows a technique for detecting the atmospheric pressure without incurring an increase in cost based on a detection value of an intake pressure sensor disposed in an intake passage of an internal combustion engine.
[Patent Document] Japanese Patent Application Laid-Open No. 2002-30981 (pages 2 to 3)
[0004]
[Problems to be solved by the invention]
By the way, in the foregoing, when applied to an independent intake multi-cylinder internal combustion engine, the intake pressure of a specific cylinder is detected by an intake pressure sensor disposed in the intake passage (engine intake pipe), and the intake pressure is detected. The atmospheric pressure is calculated based on However, the difference in the behavior of the intake pressure for each cylinder is not taken into consideration, and if any abnormality occurs in the behavior of the intake pressure detected in the specific cylinder in which the intake pressure sensor is provided, for example, fuel injection There was a problem that the correction according to the atmospheric pressure with respect to the amount became inappropriate and the operating state of the internal combustion engine became unstable.
[0005]
Therefore, the present invention has been made to solve such a problem, and based on the intake pressure detected for each cylinder in consideration of the difference in the behavior of the intake pressure for each cylinder in an independent intake multi-cylinder internal combustion engine. An object of the present invention is to provide an atmospheric pressure detection device for a multi-cylinder internal combustion engine capable of detecting an accurate atmospheric pressure.
[0006]
[Means for Solving the Problems]
According to the atmospheric pressure detection device for a multi-cylinder internal combustion engine according to claim 1, when the execution condition for the atmospheric pressure detection according to the operating state of the internal combustion engine is satisfied by the execution condition determining means in the independent intake multi-cylinder internal combustion engine, Intake pressure introduced into the downstream side of the throttle valve of each intake passage by a plurality of intake pressure detection means is taken in at a predetermined timing in a predetermined period in the combustion cycle for each cylinder of the internal combustion engine by the atmospheric pressure calculation means. An estimated atmospheric pressure value is calculated based on the intake pressure, and an average value of the estimated atmospheric pressure value is set as the atmospheric pressure by the atmospheric pressure setting means. For this reason, since the update frequency can be increased while maintaining the accuracy of the atmospheric pressure estimated value calculation, the reliability of the finally set atmospheric pressure is improved. For example, the fuel injection amount, the ignition timing, etc. Therefore, it is possible to carry out a fine correction with high accuracy and to maintain a good operating state of the internal combustion engine.
[0007]
The atmospheric pressure calculating means in the atmospheric pressure detecting device of the multi-cylinder internal combustion engine according to claim 2 calculates the atmospheric pressure estimated value when the difference in intake pressure by the intake pressure detecting means is equal to or smaller than a predetermined value. As a result, the accuracy of the estimated value calculation is improved, and as a result, the reliability of the atmospheric pressure is further improved.
[0008]
In the atmospheric pressure calculation means in the atmospheric pressure detection device for a multi-cylinder internal combustion engine according to claim 3, when at least one intake pressure detection means becomes abnormal among the plurality of intake pressure detection means, the intake pressure detection means by other intake pressure detection means By setting the atmospheric pressure based on the atmospheric pressure estimated value based on the atmospheric pressure, the fail-safe process is executed using the atmospheric pressure.
[0009]
In the atmospheric pressure setting means in the atmospheric pressure detecting device of the multi-cylinder internal combustion engine according to claim 4, the atmospheric pressure is set when the estimated atmospheric pressure value by the atmospheric pressure calculating means is within a predetermined range. Thereby, the reliability in the atmospheric pressure estimated value for setting the atmospheric pressure can be improved.
[0010]
In the atmospheric pressure setting means in the atmospheric pressure detecting device of the multi-cylinder internal combustion engine according to claim 5, when the deviation of the estimated atmospheric pressure value by the atmospheric pressure calculating means is within a predetermined range, the average value of the estimated atmospheric pressure value is set as the atmospheric pressure. Is set. That is, the setting of the atmospheric pressure is limited when the deviation of the estimated atmospheric pressure is within a predetermined range, and the atmospheric pressure is not updated when the internal combustion engine in which the behavior of the intake pressure for each cylinder is different is in an operating state. Therefore, the reliability of the finally set atmospheric pressure is improved.
[0011]
According to the atmospheric pressure detection apparatus for a multi-cylinder internal combustion engine according to claim 6, since the internal combustion engine is an independent intake two-cylinder engine in which an intake air amount is supplied independently for each cylinder, The behavior is taken into account and a more accurate atmospheric pressure is detected.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[0013]
FIG. 1 is a schematic configuration diagram showing an independent intake two-cylinder internal combustion engine and its peripheral devices in a motorcycle to which an atmospheric pressure detection device for a multi-cylinder internal combustion engine according to an embodiment of the present invention is applied.
[0014]
In FIG. 1, the internal combustion engine 1 is configured as a spark ignition type of four-stroke two-cylinder (# 1 cylinder and # 2 cylinder) with independent intake, and the intake air is air cleaner 2 from the upstream side, and independent intake from the air cleaner 2. The # 1 cylinder throttle valve 4 and the # 2 cylinder throttle valve 4 'respectively disposed in the bifurcated intake passages 3 and 3' pass through the intake passages 3 and 3 '. Injector 5 (fuel injection valve) and fuel injected from # 2 cylinder injector 5 'are respectively mixed and mixed with a predetermined air-fuel ratio, # 1 cylinder intake port 6 and # 2 cylinder intake port (not shown) To be supplied into each cylinder. Also, the cylinder head of the internal combustion engine 1 is provided with a # 1 cylinder spark plug 7 and a # 2 cylinder spark plug 7 ', respectively, and a high voltage is applied from the ignition coil / igniter 8 at each ignition timing. ′ To ignite the air-fuel mixture in each cylinder. The exhaust gas burned in each cylinder of the internal combustion engine 1 passes through the exhaust passages 12 and 12 'from the exhaust port 11 of the # 1 cylinder and the exhaust port (not shown) of the # 2 cylinder, and downstream after the merge. It passes through the three-way catalyst 13 disposed on the side and is discharged into the atmosphere.
[0015]
An intake air temperature sensor 21 is disposed in the air cleaner 2, and the intake air temperature THA [° C.] flowing into the air cleaner 2 is detected by the intake air temperature sensor 21. Further, an intake pressure sensor 22 for the # 1 cylinder and an intake pressure sensor 22 'for the # 2 cylinder are disposed on the downstream side of the throttle valves 4 and 4' in the bifurcated intake passages 3 and 3 ', respectively. Cylinder intake pressure sensor 22 detects # 1 cylinder intake pressure PM1 [kPa: kilopascals], and # 2 cylinder intake pressure sensor 22 'detects # 2 cylinder intake pressure PM2 [kPa]. A throttle opening sensor 23 is disposed on the throttle valves 4 and 4 'connected by the link mechanism, and the throttle opening TA [°] of the throttle valves 4 and 4' is detected by the throttle opening sensor 23. The A water temperature sensor 24 is disposed in the cylinder block of the internal combustion engine 1, and the coolant temperature THW [° C.] in the internal combustion engine 1 is detected by the water temperature sensor 24.
[0016]
A crank angle sensor 25 is disposed on a crankshaft (not shown) of the internal combustion engine 1, and an engine rotational speed NE [rpm] of the internal combustion engine 1 is detected by a crank angle signal from the crank angle sensor 25. Further, based on the crank angle signal from the crank angle sensor 25 and the fluctuations in the intake pressure PM1 by the intake pressure sensor 22 of the # 1 cylinder and the intake pressure PM2 by the intake pressure sensor 22 'of the # 2 cylinder accompanying the combustion cycle, cylinder discrimination and A crank angle reference position is detected. In addition, a power supply voltage sensor 29 is provided in the in-vehicle battery (not shown), and the power supply voltage sensor 29 detects the power supply voltage VB [V: volts].
[0017]
On the other hand, the fuel pumped up from the fuel tank 31 by the fuel pump 32 is pumped in the order of the fuel pipe 33, the fuel filter 34, the fuel pipe 35, and the delivery pipe 36. From the delivery pipe 36, the # 1 cylinder injector 5 and # Each is supplied to a two-cylinder injector 5 '. Excess fuel in the delivery pipe 36 is returned into the fuel tank 31 through a path of a pressure regulator 37 and a return pipe 38. The pressure regulator 37 adjusts the fuel pressure in the delivery pipe 36 so that the differential pressure between the fuel pressure (fuel pressure) in the delivery pipe 36 and the intake pressure becomes constant.
[0018]
An ECU (Electronic Control Unit) 40 that controls the operating state of the internal combustion engine 1 includes a CPU 41 as a central processing unit that executes various known arithmetic processes, a ROM 42 that stores a control program, a control map, and various data. The RAM 43, the B / U (backup) RAM 44, etc. are stored as logical operation circuits. The input port 45 for inputting the detection signals from the various sensors described above, the injector 5 for the # 1 cylinder, the # 2 cylinder It is connected via a bus 47 to various actuators such as the injector 5 ′ and the fuel pump 32, and an output port 46 that outputs each control signal to the ignition coil / igniter 8.
[0019]
Here, regarding the behavior of the intake stroke PM which is the combustion cycle of one cylinder of the independent intake two-cylinder internal combustion engine 1 of the present embodiment → the compression stroke → the combustion (expansion) stroke → the intake pressure PM [kPa] in the exhaust stroke. This will be described with reference to the time chart of FIG.
[0020]
As shown in FIG. 2, the intake pressure PM rises from the atmospheric pressure to the positive pressure momentarily at the beginning of the intake stroke, then greatly decreases to the negative pressure side, reaches a minimum value (bottom pressure), and then increases by the initial compression stroke. It turns back to atmospheric pressure level by the end of the combustion stroke. For this reason, although depending on the operating state of the internal combustion engine 1, it can be said that the intake pressure PM in the exhaust stroke is at the atmospheric pressure level.
[0021]
Here, when the engine rotational speed NE is constant, the minimum value of the intake pressure PM increases and the minimum value as the throttle opening degree TA increases from “small (closed side)” to “large (open side)”. The speed of rising from to atmospheric pressure level becomes faster. Therefore, as the throttle opening degree TA becomes “large”, as shown in FIG. 2, the detection period for taking in the intake pressure PM can be extended to the combustion stroke and further to the middle of the compression stroke in addition to the exhaust stroke. Thus, the atmospheric pressure can be estimated by sequentially taking in the intake pressure PM at the timing when the intake pressure PM becomes the atmospheric pressure level.
[0022]
Next, based on the flowchart of FIG. 3 which shows the processing procedure of the atmospheric pressure estimated value calculation in CPU41 in ECU40 used with the atmospheric pressure detection apparatus of the multicylinder internal combustion engine concerning one Example of embodiment of this invention. This will be described with reference to FIGS. 2 and 4 described above. Here, FIG. 4 is a time chart showing transition states of various sensor signals and various control amounts corresponding to the processing of FIG. This atmospheric pressure estimated value calculation routine is repeatedly executed by the CPU 41 in synchronization with the crank angle signal.
[0023]
In FIG. 3, first, it is determined in step S101 whether the engine speed NE based on the crank angle signal detected by the crank angle sensor 25 is within a predetermined operating range. When the determination condition of step S101 is satisfied, that is, when the engine speed NE is in the predetermined operating range [from time t0 to time t1 (from ignition switch ON operation to immediately before cranking start) shown in FIG. 4, time t2 to time t3 (During idle operation), from time t3 to time t4 (during acceleration operation), from time t4 to time t5 (during steady operation), after time t6 (during steady operation)], it is assumed that the intake pressure detection condition is met. The process proceeds to S102. In step S102, it is determined whether the throttle opening degree TA detected by the throttle opening degree sensor 23 is within a predetermined operation range. In this determination, the throttle opening degree TA is used as the load of the internal combustion engine 1, but the intake pressure PM1 from the intake pressure sensor 22 of the # 1 cylinder or the intake pressure PM2 from the intake pressure sensor 22 'of the # 2 cylinder is used. You can also.
[0024]
When the determination condition of step S102 is satisfied, that is, when the throttle opening degree TA is in the predetermined operation range [other than time t5 to time t6 shown in FIG. Excluding)], it is determined that the intake pressure detection condition is satisfied, and the process proceeds to step S103. In step S103, the intake pressure maximum value PM1max of the intake pressure PM1 is detected by the intake pressure sensor 22 of the # 1 cylinder in the period from the intake stroke of the # 1 cylinder to the compression stroke. The detection of the maximum intake pressure value PM1max may be performed until just before the intake pressure PM1 is taken in to calculate an atmospheric pressure estimated value in step S107 described later.
[0025]
Next, the process proceeds to step S104, and it is determined whether the intake pressure maximum value PM1max detected in step S103 exceeds the value obtained by adding the predetermined value α to the atmospheric pressure (see the level indicated by the two-dot chain line in FIG. 2). Is done. This determination process is to prevent the intake pressure behavior caused by backfire or the like from affecting the atmospheric pressure estimation. When the determination condition of step S104 is not satisfied, that is, when the inequality of PM1max ≦ (atmospheric pressure + α) is satisfied when the maximum intake pressure value PM1max is equal to or less than the value obtained by adding the predetermined value α to the atmospheric pressure, the process proceeds to step S105. In step S105, an intake pressure behavior that satisfies the inequality of PM1max> (atmospheric pressure + α) in step S104 is likely to occur once, so that a predetermined period from when the inequality of PM1max> (atmospheric pressure + α) is satisfied. It is determined whether or not elapses.
[0026]
When the determination condition of step S105 is satisfied, that is, when the predetermined period has elapsed since the inequality of PM1max> (atmospheric pressure + α) is satisfied, the routine proceeds to step S106, where it is determined whether it is the exhaust stroke of the # 1 cylinder. The When the determination condition of step S106 is satisfied, that is, when the exhaust stroke of the # 1 cylinder, the routine proceeds to step S107, where the intake pressure PM1 detected by the intake pressure sensor 22 of the # 1 cylinder is taken. Note that the intake pressure PM1 intake period is not only the exhaust stroke, but also the combustion stroke, depending on the throttle opening TA as the load of the internal combustion engine 1, as indicated by the solid and broken lines as the detection period in FIG. Further, the expansion may be changed to a part of the compression stroke.
[0027]
Next, the routine proceeds to step S108, where it is determined whether or not the exhaust stroke of the # 1 cylinder has ended (immediately before the intake valve of the # 1 cylinder is opened). When the determination condition in step S108 is satisfied, that is, when the exhaust stroke of the # 1 cylinder is completed, the routine proceeds to step S109, where the intake pressure deviation ΔPM1 obtained by subtracting the minimum value from the maximum value in the intake pressure PM1 read in step S107 is determined. It is determined whether it is less than the predetermined value β. When the determination condition of step S109 is satisfied, that is, when the intake pressure deviation ΔPM1 is smaller than the predetermined value β, the intake pressure PM1 read in step S107 is considered stable, and the routine proceeds to step S110, where the intake pressure PM1 is averaged. An estimated atmospheric pressure value PAS1 for the # 1 cylinder is calculated.
[0028]
Next, the routine proceeds to step S111, and during the period from the intake stroke of the # 2 cylinder to the compression stroke, the intake pressure maximum value PM2max is detected by the intake pressure sensor 22 'of the # 2 cylinder. The detection of the maximum intake pressure value PM2max may be performed until just before the intake pressure PM2 is taken in for calculating the atmospheric pressure estimated value in step S115 described later. Next, the process proceeds to step S112, where it is determined whether the intake pressure maximum value PM2max detected in step S111 exceeds the value obtained by adding the predetermined value α to the atmospheric pressure (see the level indicated by the two-dot chain line in FIG. 2). Is done. This determination process is to prevent the intake pressure behavior caused by backfire or the like from affecting the atmospheric pressure estimation.
[0029]
When the determination condition of step S112 is not satisfied, that is, when the inequality of PM2max ≦ (atmospheric pressure + α) is satisfied when the maximum intake pressure value PM2max is equal to or less than the value obtained by adding the predetermined value α to the atmospheric pressure, the process proceeds to step S113. In step S113, an intake pressure behavior that satisfies the inequality of PM2max> (atmospheric pressure + α) in step S112 is likely to occur once, so that a predetermined period from when the inequality of PM2max> (atmospheric pressure + α) is satisfied. It is determined whether or not elapses. When the determination condition in step S113 is satisfied, that is, when a predetermined period has elapsed from when the inequality of PM2max> (atmospheric pressure + α) is satisfied, the routine proceeds to step S114, where it is determined whether it is the exhaust stroke of the # 2 cylinder. The When the determination condition of step S114 is satisfied, that is, when the exhaust stroke of the # 2 cylinder, the routine proceeds to step S115, where the intake pressure PM2 detected by the intake pressure sensor 22 'of the # 2 cylinder is taken. Note that the intake pressure PM2 intake period is not only the exhaust stroke, but also the combustion stroke, depending on the throttle opening TA as the load of the internal combustion engine 1, as indicated by the solid and broken lines as the detection period in FIG. Further, the expansion may be changed to a part of the compression stroke.
[0030]
Next, the routine proceeds to step S116, where it is determined whether or not the exhaust stroke of the # 2 cylinder has ended (immediately before the intake valve of the # 2 cylinder is opened). When the determination condition of step S116 is satisfied, that is, when the exhaust stroke of the # 2 cylinder is completed, the routine proceeds to step S117, where the intake pressure deviation ΔPM2 obtained by subtracting the minimum value from the maximum value in the intake pressure PM2 read in step S115 is obtained. It is determined whether it is less than the predetermined value β. When the determination condition of step S117 is satisfied, that is, when the intake pressure deviation ΔPM2 is smaller than the predetermined value β, the intake pressure PM2 read in step S115 is considered to be stable and the routine proceeds to step S118, where the intake pressure PM2 is averaged. An estimated atmospheric pressure value PAS2 for the # 2 cylinder is calculated.
[0031]
Next, the routine proceeds to step S119, where the absolute value of the difference between the estimated atmospheric pressure value PAS1 in the # 1 cylinder calculated in step S110 and the estimated atmospheric pressure value PAS2 in the # 2 cylinder calculated in step S118 is a predetermined value γ. It is determined whether it is less than. When the determination condition of step S119 is satisfied, that is, when the inequality | PAS1-PAS2 | <γ is satisfied, it is determined that the atmospheric pressure estimated value is reliable, and the process proceeds to step S120, where the atmospheric pressure estimated value PAS is large in the # 1 cylinder. Based on the estimated atmospheric pressure value PAS1 and the estimated atmospheric pressure value PAS2 in the # 2 cylinder, the following equation (1) is calculated, and this routine is completed.
[0032]
[Expression 1]
PAS ← (PAS1 + PAS2) / 2 (1)
[0033]
Note that the estimated atmospheric pressure value PAS calculated in step S120 is compared with the estimated atmospheric pressure value stored so far, and an update process is executed when the estimated value is different. As this update process, the value may be increased or decreased by a predetermined amount without being replaced at once, or may be replaced with a value subjected to a predetermined smoothing process.
[0034]
On the other hand, when the determination condition of step S101 is not satisfied, that is, when the engine speed NE is not in the predetermined operation range [time t1 to time t2 shown in FIG. 4 (during cranking; affected by noise from a starter relay, etc. Easy period)], or when the determination condition of step S102 is not satisfied, that is, when the throttle opening degree TA is not in the predetermined operating range [time t5 to time t6 shown in FIG. Or when the determination condition of step S104 is satisfied, that is, when the inequality PM1max> (atmospheric pressure + α) is satisfied, or the determination condition of step S105 is not satisfied, that is, PM1max> When the predetermined period has not elapsed since the inequality of (atmospheric pressure + α) is satisfied, or the determination condition of step S106 is not satisfied, that is, # When it is not the exhaust stroke of one cylinder, or the determination condition of step S108 is not satisfied, that is, when the exhaust stroke of # 1 cylinder is not completed, or the determination condition of step S109 is not satisfied, that is, the intake pressure deviation ΔPM1 is When it is larger than the predetermined value β, this routine is terminated because it is not suitable for atmospheric pressure estimation.
[0035]
Further, when the determination condition of step S112 is satisfied, that is, the inequality of PM2max> (atmospheric pressure + α) is satisfied, or the determination condition of step S113 is not satisfied, that is, the inequality of PM2max> (atmospheric pressure + α) is satisfied. When the predetermined period has not elapsed since the start, or the determination condition of step S114 is not satisfied, that is, when the exhaust stroke of the # 2 cylinder is not satisfied, or the determination condition of step S116 is not satisfied, that is, the # 2 cylinder When the exhaust stroke is not finished or when the determination condition of step S117 is not satisfied, that is, when the intake pressure deviation ΔPM2 is larger than the predetermined value β or when the determination condition of step S119 is not satisfied, that is, | PAS1- When the inequality PAS2 | ≧ γ holds, this routine is terminated as being unsuitable for atmospheric pressure estimation.
[0036]
As described above, the atmospheric pressure detection device for a multi-cylinder internal combustion engine according to the present embodiment is an independent intake two-cylinder (# 1 cylinder, # 2 cylinder) engine having an independent intake system for each cylinder. As two intake pressure detection means for detecting intake pressure PM1, PM2 which is the pressure of the intake air of each cylinder introduced downstream of the throttle valves 4, 4 'disposed in the intake passages 3, 3' The intake pressure sensors 22 and 22 ', the execution condition determination means that is achieved by the ECU 40 that determines the execution condition of the atmospheric pressure detection according to the operating state of the internal combustion engine 1, and the internal combustion engine 1 when the execution condition is satisfied. Achieved by the ECU 40 that calculates the estimated atmospheric pressure values PAS1, PAS2 based on the intake pressures PM1, PM2 by the intake pressure sensors 22, 22 'taken at predetermined timings in a predetermined period in the combustion cycle of each cylinder. Atmospheric pressure calculation means, and an atmospheric pressure setting means achieved by the ECU 40 that sets an average value {(PAS1 + PAS2) / 2} of the estimated atmospheric pressure values PAS1, PAS2 for each cylinder by the atmospheric pressure calculation means as the atmospheric pressure PAS It comprises.
[0037]
That is, when the atmospheric pressure detection execution condition according to the operating state of the internal combustion engine 1 composed of two cylinders (# 1 cylinder, # 2 cylinder) of independent intake is satisfied, every predetermined timing in a predetermined period in the combustion cycle of each cylinder. An average value {(PAS1 + PAS2) / 2} of the atmospheric pressure estimated values PAS1 and PAS2 calculated based on the intake pressures PM1 and PM2 by the intake pressure sensors 22 and 22 'taken in is set as the atmospheric pressure PAS. Thereby, since the update frequency can be increased while maintaining the accuracy of calculating the atmospheric pressure estimated values PAS1, PAS2, the reliability of the finally set atmospheric pressure PAS is improved. For example, the fuel injection amount In addition, it is possible to perform a fine and accurate correction with respect to the ignition timing and the like, and to maintain the operating state of the internal combustion engine 1 satisfactorily.
[0038]
Further, the atmospheric pressure calculating means achieved by the ECU 40 of the atmospheric pressure detecting device of the multi-cylinder internal combustion engine of the present embodiment is such that the difference ΔPM1, ΔPM2 between the intake pressures PM1, PM2 by the intake pressure sensors 22, 22 ′ is a predetermined value β. In the following, that is, when ΔPM1 <β and ΔPM2 <β, the atmospheric pressure estimation values PAS1 and PAS2 are calculated. Thereby, the accuracy of the atmospheric pressure estimated values PAS1, PAS2 is increased, so that the reliability of the atmospheric pressure PAS can be further improved.
[0039]
The atmospheric pressure setting means achieved by the ECU 40 of the atmospheric pressure detecting device of the multi-cylinder internal combustion engine of the present embodiment is such that the estimated atmospheric pressure values PAS1 and PAS2 by the atmospheric pressure calculating means achieved by the ECU 40 are both within a predetermined range. Of these, that is, when there is no error in the estimated atmospheric pressure values PAS1, PAS2, the setting of the atmospheric pressure PAS is performed. Thereby, the reliability in atmospheric pressure estimated value PAS1, PAS2 for setting atmospheric pressure PAS can be improved.
[0040]
Further, the atmospheric pressure setting means achieved by the ECU 40 of the atmospheric pressure detecting device of the multi-cylinder internal combustion engine of the present embodiment has a predetermined deviation of the atmospheric pressure estimated values PAS1, PAS2 by the atmospheric pressure calculating means achieved by the ECU 40. Within the range, that is, when | PAS1−PAS2 | <γ, an average value {(PAS1 + PAS2) / 2} of the atmospheric pressure estimation values PAS1 and PAS2 is set as the atmospheric pressure PAS. As a result, when the internal combustion engine 1 in which the behavior of the intake pressure for each cylinder is different is in an operating state, the update of the atmospheric pressure PAS is not permitted, so the detection timing of the atmospheric pressure PAS is slightly reduced but finally set. The reliability of the atmospheric pressure PAS can be further improved.
[0041]
In the above embodiment, the case where the intake pressure detecting means is normal is described. However, the present invention is not limited to this, and when one intake pressure sensor becomes abnormal. The atmospheric pressure can be set by calculating the estimated atmospheric pressure based on the intake pressure by other intake pressure sensors. In this case, although the detection accuracy is somewhat inferior, fail-safe processing can be performed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an independent intake two-cylinder internal combustion engine and its peripheral devices in a motorcycle to which an atmospheric pressure detection apparatus for a multi-cylinder internal combustion engine according to an embodiment of the present invention is applied; It is.
FIG. 2 is a diagram illustrating an intake in a combustion cycle of one cylinder of an independent intake two-cylinder internal combustion engine to which an atmospheric pressure detection device for a multi-cylinder internal combustion engine according to an embodiment of the present invention is applied; It is a time chart which shows the behavior of atmospheric pressure.
FIG. 3 is a flowchart showing a processing procedure of atmospheric pressure estimated value calculation in a CPU in the ECU used in the atmospheric pressure detection device for a multi-cylinder internal combustion engine according to an example of an embodiment of the present invention; is there.
4 is a time chart showing transition states of various sensor signals and various control amounts corresponding to the processing of FIG. 3; FIG.
[Explanation of symbols]
1 Internal combustion engine 3 (# 1 cylinder) intake passage 3 '(# 2 cylinder) intake passage 4 (# 1 cylinder) throttle valve 4'(# 2 cylinder) throttle valve 22 (# 1 cylinder) intake pressure Sensor 22 '(# 2 cylinder) intake pressure sensor 23 Throttle opening sensor 24 Water temperature sensor 25 Crank angle sensor 40 ECU (electronic control unit)

Claims (6)

A plurality of intake air pressures for detecting the intake air pressure of each cylinder introduced downstream of a throttle valve disposed in each intake passage of an independent intake multi-cylinder internal combustion engine having an independent intake system for each cylinder Intake pressure detecting means of
Execution condition determination means for determining an execution condition of atmospheric pressure detection according to the operating state of the internal combustion engine;
An atmospheric pressure calculation means for calculating an estimated atmospheric pressure value based on an intake pressure by the intake pressure detection means taken at a predetermined timing of a predetermined period in a combustion cycle for each cylinder of the internal combustion engine when the execution condition is satisfied; ,
An atmospheric pressure detecting device for a multi-cylinder internal combustion engine, comprising: an atmospheric pressure setting unit that sets an average value of an estimated atmospheric pressure value for each cylinder by the atmospheric pressure calculating unit as an atmospheric pressure. 2. The multi-cylinder internal combustion engine according to claim 1, wherein the atmospheric pressure calculation unit calculates the estimated atmospheric pressure when a difference in intake pressure by the intake pressure detection unit is a predetermined value or less. Barometric pressure detection device. The atmospheric pressure calculating means calculates the estimated atmospheric pressure based on the intake pressure by the other intake pressure detecting means when at least one of the plurality of intake pressure detecting means becomes abnormal. The apparatus for detecting atmospheric pressure of a multi-cylinder internal combustion engine according to claim 1 or 2, characterized in that: The said atmospheric pressure setting means implements an atmospheric pressure setting, when the atmospheric pressure estimated value by the said atmospheric pressure calculating means is in a predetermined range, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The atmospheric pressure detection device for a multi-cylinder internal combustion engine as described. The said atmospheric pressure setting means sets the average value of the said atmospheric pressure estimated value as an atmospheric pressure, when the deviation of the atmospheric pressure estimated value by the said atmospheric pressure calculating means is in a predetermined range. The atmospheric pressure detection apparatus for a multi-cylinder internal combustion engine according to claim 4. The atmospheric pressure detection device for a multi-cylinder internal combustion engine according to any one of claims 1 to 5, wherein the internal combustion engine is an independent intake two-cylinder engine.

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