DE10355303A1 - Two-cylinder air intake detection device for detecting amounts of air sucked in for an internal combustion engine has an air flow measuring device, pressure sensors and a learning unit - Google Patents

Abstract

An air flow measuring device (14) detects amounts of air sucked in, which flows into an intake pipe (12). A pressure sensor (18) detects pressure in the intake pipe. A cylinder inner pressure sensor (21a) detects cylinder inner pressure. A learning unit calculates rates of variation in amounts of air sucked in.

Description

The invention relates to an intermediate cylinder intake air quantity detection device for an internal combustion engine with internal combustion to record the rate of deviation of the intake air quantity between cylinders or of intermediate cylinder intake air quantities.

Generally can in an internal combustion engine with internal combustion with a large number of cylinders inter-cylinder deviations the amount of intake air (amount of air introduced into a cylinder) as a result the shape difference of intake manifolds of the cylinders or deviations in valve lashes between intake valves result. Such intermediate cylinder deviations in the intake air quantity can Cause inter-cylinder deviations in torque or air-fuel ratio. If the inter-cylinder deviations in torque increase, the deviations in the engine torque increase in one cycle, whereby vibrations cause unpleasant sensations for a driver can. As the air-fuel ratio inter-cylinder deviations increase, take deviations in the air-fuel ratio of the exhaust gas, which flows into a catalytic converter in one cycle, accordingly to. Consequently, the limit value of the air-fuel ratio deviations of exhaust gas exceed the cleaning capacity of the catalytic converter, which can reduce the exhaust gas purification rate.

As a countermeasure to such a problem, some methods for correcting inter-cylinder deviations in torque or deviations in air-fuel ratio have been proposed. For example, patent document 1 ( JP-A-62-17342 ) a method in which a torque sensor disposed on a crankshaft detects a torque generated on each cylinder and the fuel injection amount of each cylinder is corrected to produce the average torque of all cylinders in each cylinder.

Patent document 2 ( JP-A-2000-220489 ) proposes a method in which the air-fuel ratio of each cylinder is estimated based on the output of an air-fuel ratio sensor disposed in an exhaust pipe, and the fuel injection amount of each cylinder is corrected to compensate for the inter-cylinder deviations in the air-fuel Decrease ratio.

Generally, a throttle valve controls the intake air volume. In recent years, however, it has become changeable Intake valve mechanism for changing the stroke quantity of the intake valve. The lift amount of the intake valve is according to the position the accelerator pedal or the conditions controlled engine operation so that the intake air amount controlled becomes. Such an amount of intake air through the variable intake valve is controlled is advantageous because the amount of intake air is reduced can be reduced by reducing the stroke volume of the intake valve, without constricting the air intake duct through the throttle valve. Thereby can the funding loss can be reduced, thereby reducing fuel consumption.

However, since the intake air volume control with the changeable Intake valve the amount of stroke of the intake valve at low load becomes smaller, changed the actual stroke quantity increases in relation to the rate of the target stroke quantity from cylinder to cylinder (deviations due to differences between cylinders in component tolerance and assembly tolerance), resulting in the enlargement of the Deviations in the amount of intake air between cylinders can result. Therefore can fluctuations in torque or air-fuel ratio each cylinder due to the effect of variations in the intake air quantity between Cylinders result, and therefore can Deviations in torque or in the air-fuel ratio increase.

In the aforementioned patent documents 1 and 2 torque and air-fuel ratio are detected for each cylinder, and variations in torque and air-fuel ratio are corrected by controlling the fuel injection amount of each cylinder based on the detected data. However, when variations between cylinders in the intake air amount increase, it becomes difficult to correct the variations in torque and air-fuel ratio between cylinders with a high degree of accuracy simply by correcting the fuel injection amount. In addition, it is also difficult to correct such deviations with a high degree of accuracy if the deviations in the torque and in the air-fuel ratio between cylinders are caused by a combination of a variety of causes, such as: B. Deviations in the amount of intake air and in the amount of intake fuel between cylinders.

Furthermore, an air flow measuring device or an intake pipe pressure sensor is arranged in an intake pipe assembly, which tends to be affected by the reflected waves of the intake air vibration or the air intake influence of other cylinders. Therefore, the output waveforms of the air flow meter or intake manifold pressure sensor include noise caused by the reflected waves of the intake air vibration or by the intake air influence from other cylinders. Thus, the output waveforms of the air flow measuring device or the intake pipe pressure sensor due to the effect of the reflected waves or the intake air influence are not pulsation waveforms, which are the deviations of the intake air quantity between cylinders with high accuracy reflect in some areas of operations. Therefore, deviations in the amount of intake air cannot be detected with a high degree of accuracy.

Because when a vehicle is in the real driving state, the operating state changes every second, so that the Time (or the number of times) to sample the outputs of the Luftströmungsmeßvorrichtung or the intake manifold pressure sensor in some operating areas can be adequately secured, this can also be a reason for one disorder when recording the deviations in the intake air volume between Cylinders with a high degree of accuracy.

In view of such circumstances It is an object of the present invention to provide a detection device the amount of intake air between cylinders for an internal combustion engine to create internal combustion in which deviations in the intake air quantity between cylinders (rate of deviation between cylinders) with high Degree of accuracy can be determined even in operating areas, in which data what deviations in the intake air volume between Reflect cylinders with high accuracy, not light ones Way from the output of a detection unit such. B. an air flow measuring device, are detectable. Therefore, the accuracy for detecting deviations between Cylinders can be increased in essentially all operating areas.

To the task described above to meet includes a machine a detection unit for detecting the deviations between the cylinders for recording at least one of the properties, the intake air quantity, that flows in an intake pipe the pressure in the intake pipe and the cylinder pressure for the internal combustion engine with internal combustion with a variety of cylinders, one and is adapted in such a way that in the operating area, in which is a predetermined condition for executing the deviation learning Fulfills is the rate of deviation of the amount of intake air between the cylinders or the intake air quantities cylinder for Cylinders are calculated and the calculated value as a learning value of Deviations between cylinders based on the output of the Registration unit through a learning unit of the deviation between Cylinders is learned. While in the operating range in which the condition for executing the Deviation learning not met is the rate of deviation of the intake air amount between Cylinders or the amount of intake air between cylinders depending on the current one Operating range using the learning value of the deviations between cylinders by a unit for estimating deviations estimated between cylinders.

This way the learning value the deviation between cylinders with a high degree of accuracy in learned the operating area in which the condition for executing the Deviation learning fulfilled and the data reflect the deviations in the intake air amount between cylinders from the output of the registration unit, such as. B, an air flow measuring device, reflected with a high degree of accuracy. In other business areas the rate of deviation of the amount of intake air between cylinders or the amount of intake air between cylinders depending on the current operating range using the learning value of the deviations between cylinders estimated with high accuracy, as described above, Therefore, the rate of deviation in the amount of intake air can vary between Cylinders or the amount of intake air between cylinders with relative high degree of accuracy can be calculated.

The surfaces of the Output waveform from the detection unit for a predetermined period for each Intake stroke or for every compression stroke of each cylinder by an area calculation unit calculated. Then the rate of deviation of the intake air amount between cylinders or the amount of intake air between cylinders the deviations between cylinders in the intake air quantity calculation unit based on the waveform for the predetermined period the air cylinder calculated as described above.

The reason for calculating the area of the Output waveform of the registration unit is that the effect of the noise or the like can be reduced if the area - is used compared to the case where the current baseline the registration unit is used. The period for the calculation the area is limited to a predetermined period, the period for calculation the area limited to the period that has fewer error-causing factors.

The task mentioned above and other objects, features and advantages of the present invention are detailed from the following Description clear with reference to the accompanying drawings.

1 1 is a schematic diagram showing an entire engine control system according to a first embodiment of the present invention;

2 shows a front view of a variable valve lift mechanism,

3 11 is a flowchart showing a processing flow of a basic routine for calculating the deviation between cylinders in the first embodiment of the present invention;

4 FIG. 2 shows a design diagram to show a map for converting an output voltage VAFM of an air flow measuring device into an instantaneous air flow velocity GAFM,

5 1 shows a design diagram to show a characteristic diagram of the rate of deviation of the intake air quantity between cylinders DEV,

6 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the maximum value of the current air flow rate of each cylinder according to the first embodiment;

7 1 is a flowchart showing a processing flow of a routine for calculating the rate of deviation of the amount of intake air between cylinders according to the first embodiment;

8th 1 is a flowchart showing a processing flow of a routine for correcting the deviations between cylinders according to the first embodiment;

9 FIG. 1 shows a design diagram to show a characteristic diagram of a basic stroke correction quantity FVVL1,

10 FIG. 1 shows a design diagram to show a characteristic diagram of a correction coefficient FVVL2,

11 FIG. 1 shows a time diagram to illustrate an exemplary embodiment of the first embodiment, FIG.

12 FIG. 1 shows a time diagram to illustrate an exemplary embodiment of the first embodiment, FIG.

12 FIG. 11 is a time chart showing a behavior of an output of the air flow rate measuring device;

13 1 is a flowchart showing part of a processing flow of a basic routine for calculating deviations between cylinders according to a second embodiment of the present invention;

14 FIG. 2 shows a valve characteristic diagram to explain the time-angle position of an intake valve when learning and the time-angle position of an exhaust valve when learning,

15 FIG. 1 shows a time diagram to illustrate an exemplary embodiment of the second embodiment, FIG.

16 FIG. 14 is a flowchart showing a processing flow of an intake air amount control system switching routine according to a third embodiment of the present invention; FIG.

17 FIG. 1 shows a time diagram to illustrate an exemplary embodiment of the third embodiment, FIG.

18 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the minimum value of the current intake pipe pressure of each cylinder according to a fourth embodiment of the present invention;

19 FIG. 10 is a time chart for explaining a relationship between the output of an air flow measuring device and the output of an intake pipe pressure sensor;

20 FIG. 12 is a flowchart showing a processing flow of a routine for calculating the maximum value of the in-cylinder pressure of each cylinder according to a fifth embodiment of the present invention;

21 FIG. 14 is a flowchart showing a processing flow of a main routine for calculating the area of the intake air amount according to a sixth embodiment of the present invention;

22 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the area of the intake air amount of each cylinder for a predetermined period according to the sixth embodiment;

23 FIG. 11 is a design diagram showing a map of a predetermined period P according to the sixth embodiment;

24 1 is a drawing for explaining a method of calculating the area of the intake air amount for the predetermined period P according to the sixth embodiment;

25 FIG. 11 is a flowchart showing a processing flow of a routine for calculating the rate of deviation of the amount of intake air between cylinders according to the sixth embodiment;

26 FIG. 1 shows a design diagram to show a characteristic diagram of a correction coefficient K2,

27 FIG. 11 is a time chart for explaining an example of a process of calculating the rate of deviation of the amount of intake air between cylinders according to the sixth embodiment;

28 FIG. 12 is a time chart for explaining an example of the correction of the deviation between cylinders according to the sixth embodiment;

29 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the area of intake air amount of each cylinder for a predetermined period according to a seventh embodiment of the present invention;

30 12 is a design diagram showing a map for calculating a detection delay DLY of the air flow measuring device according to the seventh embodiment;

31 12 is a drawing for explaining a method of calculating the area of the intake air amount for a predetermined period according to the seventh embodiment;

32 FIG. 13 is a time chart for explaining an example of the process of calculating the rate of deviation of the amount of intake air between cylinders according to the seventh embodiment;

33 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the area of the intake air amount of each cylinder for a predetermined period according to an eighth embodiment of the present invention;

34 1 is a drawing for explaining a method of calculating the area of the intake air amount for a predetermined period according to the eighth embodiment;

35 FIG. 12 is a time chart for explaining an example of the process of calculating the rate of deviation of the amount of intake air between cylinders according to the eighth embodiment;

36 FIG. 14 is a flowchart showing a processing flow of a main routine for calculating the area of the intake air amount according to a ninth embodiment of the present invention;

37 1 shows a design diagram to show a characteristic diagram for converting an output voltage of the intake manifold pressure sensor VMAP into an instantaneous intake manifold pressure PMAP,

38 11 is a flowchart showing a processing flow of a routine for calculating the area of the intake air amount of each cylinder for a predetermined period according to the ninth embodiment;

39 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the area of the intake air amount of each cylinder for a predetermined period according to a tenth embodiment of the present invention;

40 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the area of the intake air amount of each cylinder for a predetermined period according to an eleventh embodiment of the present invention;

41 FIG. 14 is a flowchart showing a processing flow of a main routine for calculating the area of the cylinder pressure according to a twelfth embodiment of the present invention;

42 1 shows a design diagram to show a map for converting an output voltage of an in-cylinder pressure sensor VCPS (#i) into an in-cylinder pressure CPS (#i),

43 FIG. 14 is a flowchart showing a processing flow of a routine for calculating the area of the cylinder pressure of each cylinder for a predetermined combustion period according to the twelfth embodiment;

44 FIG. 13 is a flowchart showing a processing flow of a routine for calculating the area of the cylinder pressure of each cylinder for a predetermined period during the non-combustion according to the twelfth embodiment;

45 FIG. 1 is a time chart showing an internal cylinder pressure waveform during combustion.

46 Fig. 10 is a time chart showing the in-cylinder pressure waveform when not burning, and

47 FIG. 12 is a time chart for explaining an example of the process of calculating the rate of deviation of the amount of intake air between cylinders according to the twelfth embodiment.

First embodiment

Referring to the drawings of 1 to 12 a first embodiment of the present invention will be described below. A schematic structure of the entire engine control system is given below based on the 1 described. A four-cylinder engine 11 , which is an internal combustion engine, has four cylinders 100 from a first cylinder # 1 to a fourth cylinder # 4, an air filter 13 is on the top inflow side of an intake valve 12 of the motor 11 arranged, and an air flow measuring device 14 (Detection unit) is for detecting the amount of intake air on the downstream side of the air filter 13 arranged. The air flow measuring device used here 14 is able to measure the return flow of the intake air. A throttle 15 is in the air intake pipe 12 to control the amount of air flow in the air intake pipe 12 arranged. The throttle valve 15 and a throttle opening sensor 16 are on the downstream side of the air flow measuring device 14 arranged. The opening of the throttle valve 15 is set by a DC motor or the like. The throttle opening sensor 16 detects the throttle opening.

In addition, on the downstream side of the throttle valve 15 an expansion tank 17 , an intake pipe pressure sensor 18 (Registration unit) and an intake manifold 19 arranged. The intake manifold pressure sensor 18 detects the intake pipe pressure. The intake manifold 19 directs air to the respective cylinders 100 the internal combustion engine 11 , Each of the cylinders 100 is with a fuel injector 20 for injecting fuel in the vicinity of the intake opening of the intake manifold 19 Mistake. The cylinder head of the engine 11 is with spark plugs 21 for the respective cylinders 100 provided so that the air-fuel mixture in the cylinders 100 by spark discharge of the respective spark plugs 21 is ignited.

An intake valve 28 is for introducing the air-fuel mixture into the corresponding cylinders 100 arranged. An exhaust valve 29 is for the discharge of combustion gas from the corresponding cylinders 100 arranged. The intake valve 28 and the exhaust valve 29 of the motor 11 are each with variable valve lift mechanisms 30 . 31 provided to change the stroke quantity of the valve. In addition, the intake valve 28 and the exhaust valve 29 can be provided with changeable valve setting mechanisms to change the valve setting (opening and closing time). The exhaust valve 29 can only be equipped with the variable valve timing mechanism, but not with the variable valve lift mechanism 31 ,

On the other hand is an exhaust pipe 22 of the motor 11 with a catalyst 23 provided such. B. a three-way catalyst to remove CO, HC, NOx in the exhaust gas. On the inflow side of a catalytic converter 23 there is an exhaust gas sensor 24 for detecting the air-fuel ratio or the rich or lean condition of the exhaust gas (such as an air-fuel ratio sensor, an oxygen sensor). On the cylinder block of the engine 11 is a coolant temperature sensor 25 arranged to detect the temperature of the coolant, and a crank angle sensor 26 to output pulse signals whenever the crankshaft of the engine 11 rotates by a predetermined crankshaft angle (e.g. 30 ° CA). The crankshaft angle and the engine speed are calculated based on the output signals from the crankshaft angle sensor 26 detected.

The outputs from these sensors become an engine control circuit (ECU) 27 transfer. The ECU 27 is mainly made up of a microcomputer. The ECU 27 controls the fuel injection amount of the fuel injector 20 and the ignition timing of the spark plug 21 depending on the engine operating conditions by executing various engine control programs stored in an integrated ROM (recording medium).

A structure of the variable valve lift mechanism 30 of the intake valve 28 is with reference to 2 explained. Because the variable valve lift mechanism 31 of the exhaust valve 29 essentially the same structure as the variable valve lift mechanism 30 of the intake valve 28 has its description is not made.

A link arm 34 is between a camshaft 32 and a swivel arm 33 arranged. The camshaft 32 drives the suction valve 28 and the swivel arm 33 on. A tax wave 35 by an engine 41 , such as B. a stepper motor is rotated is above the connecting arm 34 arranged. A tax wave 35 is with an eccentric cam 36 rotatable and made in one piece. The link arm 34 is pivotally mounted in the position by the axis of the eccentric cam 36 is moved with the intermediate piece of a support shaft (not shown). The link arm 34 is with a pin cam 38 provided in the middle section. The side surface of the pin cam 38 lies against the outer peripheral surface of one on the camshaft 32 arranged cam 37 on. The link arm 34 is with a push cam 39 provided at the lower end. The lower end surface of the press cam 39 lies against the upper end surface of a roller 40 which in the middle section of the swivel arm 33 is arranged.

If the cam 37 according to the rotation of the camshaft 32 turns, the pin cam moves 38 of the connecting arm 34 accordingly laterally along the shape of the outer peripheral surface of the cam 37 , The link arm 34 also pivots sideways. Because the push arm 39 with the lateral pivoting movement of the connecting arm 34 moved laterally, a roller 40 of the swivel arm 33 according to the shape of the lower end surface of the press arm 39 moved vertically. The swivel arm 33 swings vertically. The intake valve 28 is designed to move itself according to the vertical movement of the swivel arm 33 to move in the vertical direction.

If, on the other hand, the eccentric cam 36 according to the rotation of the control shaft 35 rotates, the position of the support shaft of the connecting arm moves 34 , Therefore, the position of the initial contact point between the push cam changes 39 of the connecting arm 34 and the roller 40 of the swivel arm 33 , The lower end surface of the press cam 39 of the connecting arm 34 is with a base curved surface 39a formed with such a curvature that the amount of pressure of the pivot arm 33 on its left side becomes zero (the valve lift amount of the intake valve 28 is zero). A pressing curvature surface 39b is designed so that the pressure of the swivel arm 33 becomes larger (the valve lift amount of the intake valve 28 is magnified) when viewed from the base curved surface 39a is moved to the right.

In a high lift mode, in which the valve lift amount of the intake valve 28 is larger, the Starting position of the contact point between the push cam 39 and the roller 40 according to the rotation of the control shaft 35 moved to the right. The portion of the lower end surface of the push cam 39 on which the push cam 39 with the roller 40 in contact is moved to the right when the push cam 39 by the rotation of the cam 37 is moved laterally. The maximum pressure of the swivel arm 33 increases, and therefore the maximum valve lift amount of the intake valve 28 greater. As a result, the period in which the pivot arm is extended 33 is pressed, and therefore the period in which the suction valve is extended 28 is open.

On the other hand, when in a low-lift mode in which the valve lift amount of the intake valve 28 is lower, the starting position of the contact point between the push cam 39 of the connecting arm 34 and the roller 40 of the swivel arm 33 according to the rotation of the control shaft 35 moved to the left. Accordingly, the portion of the lower end surface of the push cam 39 with the roller 40 came into contact, moved to the left when the push cam 39 by the rotation of the cam 37 is moved laterally. The maximum pressure of the swivel arm 33 becomes smaller, and therefore the maximum valve lift amount of the intake valve also increases 28 from. As a result, the period in which the pivot arm is shortened 33 is pressed, and therefore the period in which the suction valve is shortened 28 is open.

In the variable valve lift mechanism described above 30 can determine the maximum valve lift quantities and the periods in which the intake valves 28 all cylinders 100 are opened (hereinafter simply referred to as the “lift amount of the intake valve”), can be continuously changed together by the control shaft 35 by the engine 41 is rotated and the starting position of the contact point between the push cam 39 and the roller 40 of the swivel arm 33 is moved continuously. Below are the cylinders 100 as a cylinder 100 or cylinder (# 1 to # 4) for special expression. Here, the designation (#i) denotes the cylinder number and represents one of the cylinders (# 1) to (# 4).

The ECU 27 controls the variable valve lift mechanism 30 of the intake valve 28 based on the position of the accelerator pedal or the engine operating conditions by executing the control program (not shown) of the variable valve stored in the ROM. The intake air amount is controlled by the valve lift amount of the intake valve 28 is continuously changed. In the case of a system that uses the variable valve lift mechanism 30 and using the variable valve timing mechanism, both the valve lift amount and the valve timing can be continuously changed to control the intake air amount.

The ECU 27 calculates the rate of deviation of the intake air amount DEV between cylinders based on the output of the air flow measuring device 14 by executing the respective routine for correcting deviations between cylinders (as will be described later). The rate of deviation of the intake air amount DEV between cylinders, which is calculated when the operating range is in the predetermined state to perform the deviation learning, is learned as a learning value of the deviation GDEV between cylinders. If the operating range is not in the state of performing the deviation learning, then the deviation rate of the intake air amount DEV between cylinders is calculated according to the current operating range using the learning value of the deviations GDEV between cylinders. Then, the lift amount of the intake valve VVL is corrected based on the rate of deviation of the intake air amount DEV between cylinders to correct the variations in the intake air amount DEV between cylinders.

The ECU 27 also calculates the area of the output waveform (intake air amounts) from the output of the air flow measuring device 14 for a predetermined period for the respective intake strokes of the respective cylinders 100 , so that the rate of deviation of the intake air amount DEV (#i) between cylinders is calculated based on the calculated area. Then, the lift amount of the intake valve VVL is corrected based on the rate of deviation of the intake air amount DEV (#i) between cylinders, and the variations in the intake air amount are corrected. In this case, the period for calculating the area of the output waveform of the air flow measuring device 14 set to a period in which the amount of intake air hardly affects the influence of the reflected wave from the intake air pulsation or the intake air influence of other cylinders 100 subject. More specifically, the period includes the maximum intake air amount.

The detailed processing is below in the respective routines to correct the deviations between Alleviate Zy according to the present embodiment (1).

Basic routine for the calculation the deviations between cylinders

One in 3 The basic routine for calculating the deviation between cylinders shown is at the time of the A / D conversions (e.g. 4 ms cycle) of the output voltage of the air flow measuring device 14 activated. When the routine is activated, the output voltage VAFM of the air flow measuring device 14 after filtering in step 101 read. The process proceeds to step 102 in which the output voltage VAFM of the air flow measuring device 14 into the current air currents speed GAFM by the air flow measuring device 14 flows using a map of the current air flow rate GAFM in 4 is converted. The current air flow rate map GAFM is used in the case when the air flow measuring device 14 is able to detect a backflow. When the air flows backwards, the current air flow rate GAFM is shown as a minus value.

The process then proceeds to step 103, in which the count value of a crank angle counter CCRNK is read. The crankshaft angle counter CCRNK is used e.g. B. increased every 30 ° CA by 1 based on the output signals of the crankshaft angle sensor 26. Therefore, 24 counting steps of the crankshaft angle counter CCRNK correspond to one cycle (720 ° CA). The crankshaft angle counter CCRNK is reset to "0" when the count value reaches "24". The rotational position of the crankshaft in which the crankshaft angle counter CCRNK shows the value 0 corresponds to the top dead center of the compression stroke (compression TDC) of the first cylinder # 1. The rotational positions of the crankshaft, in which the crankshaft angle counter CCRNK the values 6 . 12 and 18 shows, are respectively set according to the compression TDCs of the third cylinder # 3, the fourth cylinder # 4 and the second cylinder # 2.

In the subsequent step 104, a routine for calculating the maximum value of the current air flow velocity ( 6 ) for each cylinder 100 executed to the maximum value GAPEAK (#i) of the current air flow velocity GAFM in each cylinder 100 during a period corresponding to its intake stroke.

Then, the process proceeds to step 105, in which a routine for calculating the rate of deviation of the amount of intake air between cylinders ( 7 ) is performed. Here, the rate of deviation of the intake air amount DEV (#i) between cylinders is calculated based on the maximum value of the current air flow rate GAPEAK (#i) in each cylinder.

Then the process continues to step 106, in which it is determined whether the condition for executing the Deviation learning fulfilled is or not. The conditions for running deviation learning tools are both conditions 1 and 2 as shown below.

• 1. The vehicle is in one of the following Conditions: Fuel cut-off mode, starting mode, Operation at reduced speed (e.g. when braking or then, when the accelerator pedal is released).
• 2. If the engine speed NE is below a predetermined value (z. B. 2000 min ^-1) and the intake air amount GA is at least a predetermined value (eg. As a value corresponding to the amount of intake air during the idling operation).

In this case, the above-described condition "1" is determined for the following reasons. When the vehicle is in the fuel cut mode or in the start mode, the non-combustion in the cylinder 100 causes, and therefore the air flow is not affected by speed variations due to combustion. Therefore, the output waveform of the air flow measuring device 14 a pulsation waveform that reflects the deviations in the amount of intake air between cylinders with a high degree of accuracy. Here the deviation rate of the intake air quantity DEV (#i) between cylinders can be calculated and learned with a high degree of accuracy.

In the system that controls the intake air amount by changing the lift amount of the intake valve, the lift amount of the intake valve is reduced during the operation at a reduced speed. Therefore, the ratio of the deviations of the actual stroke amount with respect to the target stroke amount in each cylinder increases 100 on. Deviations in the amount of intake air in each cylinder 100 increase, and thus the deviation rate of the intake air amount DEV (#i) between cylinders can be calculated and learned with a high degree of accuracy.

The above-described condition "2" is determined for the following reasons. As the period of a cycle becomes longer with the decrease in the engine speed NE, the period (or the number of times) for sampling the output of the air flow measuring device can 14 be extended. When the intake air amount GA is large, the amplitude of the intake air pulsation increases accordingly, and thus the characteristic values (maximum value, minimum value, area or the like) of the intake air amount pulsation used to calculate the rate of deviation of the intake air amount DEV (#i) between cylinders can be easily determined. Based on these reasons, in the operating range in which the engine speed NE is small and the intake air amount GA is large, the rate of deviation of the intake air amount DEV (#i) between cylinders can be learned with a high degree of accuracy.

There is another advantage. Even if the valve operating states of the valves, such as. B. an intake valve, an exhaust valve, a throttle valve, are changed in the operating states, which for learning the deviations between cylinders are suitable in operating at reduced speed, deviations in torque, generated accordingly, not noticed by the driver become.

If both of the conditions "1" and "2" described above are satisfied, the condition for performing the deviation learning is satisfied. However, the condition for performing the deviation learning is not satisfied if either or both of the conditions "1" and "2" described above is not fulfilled.

If it is determined that the condition to run learning deviation the process continues to step 107, in which the deviation rate of the intake air amount DEV (#i) between cylinders, which is calculated when in the Operating state in which the condition for performing the deviation learning Fulfills is, as the learning value of the deviations GDEV (#i) between cylinders is learned (saved). The process in the steps of 105 to 107 executed as described above serves as a deviation learning unit, as in the attached claims is defined.

Then, in step 108, the average lift amount of the intake valve VVL, which is obtained when the learning value of the deviations GDEV (#i) between cylinders is learned as a reference lift amount of the intake valve GVVL. In this case, the average stroke quantity of the intake valve VVL can be determined from the rotational position of the drive motor 41 of the variable valve lift mechanism 30 be calculated.

Then the process continues to step 109, in which an inter-cylinder deviation learning completion flag GXVVL is turned "ON", what the completion of the Inter-cylinder deviation learning means and the routine becomes completed.

On the other hand, in the step 106 is determined when the condition for executing the deviation learning not fulfilled the process continues to step 110, in which it is determined whether learning the learning value the deviations GDEV (#i) between cylinders in step 110 is completed or not (whether the inter-cylinder deviation learning completion flag GXVVL Is ON or not). When learning the deviations between cylinders is not completed, the routine ends as it is.

On the other hand, if it is determined that the learning of the learning value of the deviations GDEV (#i) between cylinders is completed, the process proceeds to step 111. Here, the deviation rate of the intake air quantity DEV (#i) between cylinders according to the current mean stroke quantity of the Intake valve VVL calculated in step 111. The VVL is calculated using the learning value of the deviations GDEV (#i) between cylinders and the ratio between the current mean stroke quantity of the suction valve VVL and the reference stroke quantity of the suction valve GVVL (VVL / GVVL) in the characteristic diagram of the deviation rate of the suction air quantity DEV (#i). calculated between cylinders as in 5 is shown. In this case, the stored value of the deviation rate of the intake air amount DEV (#i) between cylinders, which is calculated in step 105, is replaced by the estimated value, which is calculated in step 111. The processing in step 111 serves as an inter-cylinder deviation estimation unit.

The intake air amount between cylinders can be obtained by multiplying the rate of deviation of the intake air amount DEV (#i) between cylinders and the intake air amount GA (average air flow rate) by the air flow measuring device 14 is grasped.

In the routine described above becomes the rate of deviation of the intake air amount DEV (#i) between cylinders for all Operating areas calculated in step 105. However, it can be in one be modified in such a way that the processing in step 105 executed if "YES" is determined in step 106. In this case, the rate of deviation of the intake air amount becomes DEV (#i) calculated between cylinders only if in the operating areas, in which the condition for performing deviation learning Fulfills and the calculated value as the learning value of the deviations GDEV (#i) is learned.

Routine for calculation the maximum value of the instantaneous air flow velocity in each cylinder

When the routine for calculating the maximum value of the current air flow velocity in each cylinder 100 , as in 6 shown in step 104 in 3 is activated, it is determined in step 201 whether the current air flow rate GAFM by the air flow measuring device 14 is determined, the maximum value is or not. The method for determining the maximum value is such that the current instantaneous air flow rate GAFM is compared with the previous measurement and it is determined whether or not the change direction of the instantaneous air flow rate GAFM is reversed from increase to decrease.

If the current air flow rate GAFM is determined not to be the maximum value in step 201, the subsequent processing is not necessary, and therefore the routine completed. Then when the current air flow velocity GAFM reaches the maximum value, the process proceeds to step 202 to determine whether the count value of the crankshaft angle counter CCRNK = 12-17 (i.e., the period corresponding to the intake stroke of the first cylinder # 1) or not. If CCRNK = 12-17, the process continues to step 203, and the maximum value of the current air flow speed GAFM in the period corresponding to the intake stroke of the first cylinder # 1 is called the maximum value of the current air flow rate of the first cylinder # 1 GAPEAK (# 1).

If "No" is determined in step 202 as described above and the crank angle counter count is determined to CCRNK = 6-11 in step 204 (ie, the period corresponding to the on suction stroke of the second cylinder (# 2), the process proceeds to step 205, in which the maximum value of the current air flow rate GAFM during the period corresponding to the suction stroke of the second cylinder # 2 to the maximum value of the current air flow rate of the second cylinder # 2 GAPEAK (# 2) is determined.

If "No" is determined in steps 202 and 204 and the count value of the crankshaft angle counter is determined in step 206 to CCRNK = 18-23 (i.e. the period corresponding to the intake stroke of the third cylinder # 3), the process continues to step 207, in which the maximum value of the current air flow rate GAFM during the period corresponding to the intake stroke of the third cylinder # 3 than the maximum value of the instantaneous air flow rate GAFM des third cylinder # 3 GAPEAK (# 3) is determined.

If in steps 202, 204 and 206 "No" is determined, i. i.e. when the count value of the crankshaft angle counter as CCRNK = 0 - 5 is determined (i.e. the period corresponding to the intake stroke of the fourth cylinder # 4), the process continues to step 208, in which the maximum value of the current Air flow rate GAFM during the period corresponding to the intake stroke of the fourth cylinder # 4 as the maximum value of the fourth air instantaneous air velocity Cylinder # 4 GAPEAK (# 4) is determined.

As in 12 shown, represents the output of the air flow measuring device 14 (Current Air Flow Rate GAFM) represents the pulsation waveform representing the amount of intake air in each cylinder 100 reflects. Therefore, by calculating the characteristic values (maximum value, minimum value, mean value, amplitude value, area, length of path, etc.) of the current air flow rate, which is caused by the air flow measuring device 14 at the intervals corresponding to the intake stroke of each cylinder 100 is the characteristic of the pulsation waveform, which is the intake air amount GA in each cylinder 100 reflects, be calculated. Thus, using the characteristic value, the rate of deviation of the amount of intake air between cylinders, which reflects the variations of the amount of intake air between cylinders, can be calculated.

Routine for calculation the rate of deviation of the amount of intake air between cylinders

In the 7 shown routine for calculating the rate of deviation of the amount of intake air between cylinders ( 105 in 3 ) is carried out for each stroke (every 180 ° CA in the case of the four-cylinder engine). When this routine is activated, the maximum instantaneous air flow rate values in each cylinder GAPEAK (#i) are read in step 5301, and in the next step 302 the maximum instantaneous air flow rate values GAPEAK (#i) in each cylinder 100 between the cylinders 100 adjusted to an adjusted value of the maximum value of the current air flow rate GAPEAKSM (#i) for each cylinder 100 to obtain. GAPEAKSM (#i) = GAPESKSM (# i-1) + K1 × {GAPAK (#i) - GAPEAKSM (# i-1)}

In the above equation, K1 is an adaptation coefficient and GAPEAKSM (# I-1) is an adaptation value of the maximum value of the current air flow rate of the (# i-1) th cylinder 100 ,

The process then continues to step 303, in which the deviation rate of the intake air amount DEV (#i) between cylinders using the following equation is calculated.

Equation 1

The denominator in the above equation is an average of the adaptation values GAPEAKSM (#i) of the maximum values of the current air flow velocities of all cylinders 100 , and K2 is a correction coefficient for converting the deviations of the maximum value of the current air flow rate into the deviations of the intake air amount.

As is clear from the equation 1 shown above, the rate of deviation of the intake air amount is DEV (#i) in each cylinder 100 a value obtained by dividing the adjustment value of the inter-cylinder deviation rate of the intake air amount GAPEAKSM (#i) in each cylinder 100 is obtained by the mean of the adaptation values of the intermediate cylinder deviation rates of the intake air quantity of all cylinders and is then multiplied by the correction coefficient K2.

Correction routine of intermediate cylinder deviations

In the 8th The routine for correcting the inter-cylinder deviation shown is executed in a predetermined regular cycle while the engine is operating. When this routine is activated, it is determined in step 401 whether or not the learning of the inter-cylinder deviation learning value GDEV (#i) is completed (whether the inter-cylinder deviation learning completion flag GXVVL is "ON" or not). If the learning of the inter-cylinder deviations is not completed , the routine is completed without executing the inter-cylinder deviation correction process from step 402.

On the other hand, if it is determined that the learning of the inter-cylinder deviations is completed or the condition for performing the correction in step 401 is satisfied, the processing related to the correction of the inter-cylinder deviations is carried out from step 5402 in the following manner. In step 402, the rate of deviation of the intake air amount DEV (#i) between cylinders is read, which is finally determined by the in 3 basic routine shown for calculating the intermediate cylinder deviation is obtained.

Then the process proceeds to step 403, in which a basic stroke correction amount FVVL1 (#i) in each cylinder 100 according to the deviation rate of the intake air amount DEV (#i) between cylinders using an in 9 shown map is calculated. According to the in 9 In the map shown, the basic stroke correction amount FVVL1 (#i) is a reduced value (minus value) in the area in which the rate of deviation of the intake air amount DEV (#i) between cylinders is a positive value, and the basic stroke correction amount FVVL1 (#i) is an increased value (Plus value) in the range in which the deviation rate of the intake air amount DEV (#i) between cylinders is a negative value. In other words, when the intake air amount of a certain cylinder 100 in relation to the mean intake air quantities of all cylinders 100 becomes larger, the reducing correction quantity increases accordingly on the basis of the basic stroke correction quantity FVVL1 (#i). In contrast, if the intake air volume of a particular cylinder 100 in relation to the mean intake air quantities of all cylinders 100 is reduced, the incremental correction amount increases accordingly based on the basic stroke correction amount FVVL1 (#i). In a predetermined range in which the deviation rate of the intake air amount DEV (#i) between cylinders is approximately zero, the basic stroke correction amount FVVL (#i) is set to zero, and therefore the lift amount of the intake valve VVL is not corrected.

After the engine speed NE and intake air amount GA (average air flow rate) by the air flow measuring device 14 is detected, in the next step 404 are read, the process proceeds to step 405, in which the in 10 The map of the correction coefficient FVVL2 shown is searched, and then the correction coefficient FVVL2 (#i) according to the current engine operating conditions (e.g., the engine speed NE and the intake air amount GA) of each cylinder 100 calculated.

In general, when the intake air amount GA is reduced (when the lift amount of the intake valve is reduced), it is accessible for the correction of the lift amount of the intake valve. Therefore, the map of the correction coefficient FVVL2 in 10 set in such a manner that the correction coefficient FVVL2 is decreased as the intake air amount GA decreases.

Then the process proceeds to step 406, in which the basic stroke correction amount FVVL1 (#i) of each cylinder 100 is multiplied by the correction coefficient FVVL2 (#i) by a stroke correction amount FVVL (#i) for each cylinder 100 to get. FVVL (#i) = FVVL1 (#i) × FVVL2 (#i).

Then the process proceeds to step 407, in which the stroke correction amount FVVL (#i) of each cylinder 100 to the mean value of the stroke quantities of the intake valves VVL of all cylinders 100 is added before the correction in order to obtain a final set stroke quantity of the intake valve VVL.

In this case, in the period in which the count value of the crankshaft angle counter CCRNK = 12-17 (that is, the period corresponding to the intake stroke of the first cylinder # 1), the final target lift amount of the intake valve VVLM becomes using the valve lift correction amount FVVL (# 1 ) of the first cylinder # 1 is calculated according to the following equation. VVLM = VVL + FVVL (# 1).

For the period in which the count value of the crankshaft angle counter CCRNK = 6 - 11 (that is, the period corresponding to the intake stroke of the second cylinder # 2), the final target lift amount of the intake valve VVLM becomes using the valve lift correction amount FVVL (# 2) of the second Cylinder # 2 is calculated according to the following equation. VVLM = VVL + FVVL (# 2).

For the period in which the count value of the crank angle counter CCRNK = 18-23 (that is, the period corresponding to the intake stroke of the third cylinder # 3), the final target lift amount of the intake valve VVLM becomes using the valve lift correction amount FVVL (# 3) of the third Cylinder # 3 calculated according to the following equation. VVLM = VVL + FVVL (# 3).

For the period in which the count of the crank angle counter CCRNK = 0-5 (i.e., the period corresponding to the intake stroke of the fourth cylinder # 4), the final target lift amount of the intake valve VVLM is determined using the valve lift correction amount FVVL (# 4 ) of the fourth cylinder # 4 is calculated according to the following equation. VVLM = VVL + FVVL (# 4).

The process then proceeds to step 408, in which the engine 41 of the variable valve lift mechanism 30 of the intake valve 28 at high speed according to the final target stroke quantity of the intake valve VVLM of each cylinder 100 is driven, which corresponds to the suction stroke of each cylinder 100 is changed, and then the lift amount of the intake valve for each intake stroke of each cylinder 100 corrected so that the intake air amount GA of each cylinder 100 is corrected. Accordingly, the deviations in the amount of intake air between cylinders are corrected.

In the routine for correcting the deviations between cylinders, the correction of the deviations between cylinders is not carried out until the learning of the deviations between cylinders is not completed. However, it is also possible to perform the correction of the deviations between cylinders using the deviation rate of the intake air amount DEV (#i) between cylinders, which is carried out in step 105 of FIG 3 is calculated until the learning of the deviations between cylinders is completed.

Referring to the timing diagram of the 11 an example of the present first embodiment shown above will be described. In the period in which the condition for executing the correction of the deviation between cylinders is satisfied and the inter-cylinder deviation correction execution flag is turned ON, the deviation rate of the intake air amount DEV (#i) between cylinders in each cylinder 100 based on the output of the air flow measuring device 14 calculated per cycle (current air flow velocity GAFM). The deviation rate of the intake air amount DEV (#i) between cylinders, which is calculated when the condition for executing the deviation learning is satisfied and the deviation learning execution flag is ON, is learned as a learning value of the deviations GDEV (#i) between cylinders. In addition, the average of the lift amounts of the intake valves VVL, which is calculated when the learning value of the deviations GDEV (#i) between cylinders is learned, is learned as a reference lift amount of the intake valve GVVL.

In the period in which the inter-cylinder deviation learning completion flag is OFF is because the condition to run learning deviation is not met is after learning the learning value of the deviation GDEV (#i) between Cylinders is completed and the inter-cylinder deviation learning completion flag GXVVL Is turned ON, the final rate of deviation of the intake air quantity DEV (#i) between cylinders using the learning value of the deviations GDEV (#i) between cylinders and the ratio of the current mean Stroke quantity of the intake valve VVL in relation to the reference stroke quantity of the Intake valve GVVL (VVL / GVVL) calculated.

The first described above embodiment is formed, the rate of deviation of the intake air quantity DEV (#i) to learn between cylinders, which if the condition for To run learning deviation and the vehicle is in the operating range in which the Calculation accuracy of the deviation rate of the intake air quantity DEV (#i) guaranteed between cylinders can be considered as a learning value of the deviations GDEV (#i) between Cylinders is calculated. Therefore, the learning value of the deviations GDEV (#i) learned between cylinders with a high degree of accuracy become.

The present embodiment is configured to estimate the rate of deviation of the intake air amount DEV (#i) between cylinders according to the current operating range using the learning value of the deviations GDEV (#i) between cylinders with high degree of accuracy in the operating range in which the condition for executing the Learning is not fulfilled. Therefore, the rate of deviation of the intake air amount DEV (#i) between cylinders can be calculated with a relatively high degree of accuracy even in the operating range in which the output waveform of the air flow measuring device 14 is not the pulsation waveform or in the operating range in which there is sufficient time (or the number of times) to sample the output of the air flow meter 14 not guaranteed who that can. The pulsation waveform reflects the deviations in the amount of intake air between cylinders with a high degree of accuracy. Therefore, the detection accuracy for deviations between cylinders in almost the entire operating range can be increased so that the deviation of the amount of intake air between cylinders can be corrected with a high degree of accuracy in the entire operating range. Thus, the deviations in both torque and air-fuel ratio between cylinders can be reduced.

Second embodiment

The operating conditions of the intake valve 28 , the exhaust valve 29 and the throttle valve 15 are not necessarily suitable for calculating the deviation rate of the intake air amount DEV between cylinders if the condition for performing the deviation learning is satisfied.

Hence the in 13 to 15 Shown second embodiment of the present invention, the valve operating conditions of the intake valve 28 , the exhaust valve 29 and the throttle valve 15 to change in the valve operating conditions for learning. Then, the deviation rate of the intake air amount DEV between cylinders is calculated, and the calculated value is learned as the learning value of the deviation GDEV between cylinders under the condition of performing the deviation learning.

Processing the in 13 Basic routine shown for calculating the deviation between cylinders is described below. When this routine is activated, the maximum value GAPEAK (#i) of the current air flow rate GAFM in the period becomes the intake stroke of each cylinder 100 as in steps 101 to 104 of the 3 calculated as described in connection with the first embodiment. Subsequently, the process proceeds to step 106, in which it is determined in the same manner as in the first embodiment whether or not the condition for performing the deviation learning is satisfied.

When it is determined that the condition for performing the deviation learning as a result of the determination is satisfied, the process proceeds to step 106a, in which the throttle opening TA is changed to the throttle opening KTA for learning. The throttle valve opening KTA for learning is set to the full opening or an opening in which the pressure in the intake pipe is substantially the ambient pressure. Accordingly, the amplitude of the intake air pulsation caused by the air flow measuring device 14 is detected on the inflow side of the throttle valve 15 is arranged to be increased. Thus, the characteristic value of the intake air pulsation (e.g., the maximum value) used for calculating the rate of deviation of the intake air amount DEV (#i) between cylinders is easily determinable, whereby the state occurs which is necessary for learning the learning value of the GDEV deviation between cylinders is suitable.

Then the process proceeds to step 106, in which the lift amount of the suction valve VVL is changed to the lift amount of the suction valve for learning KVVL. The stroke amount of the suction valve for learning KVVL is set to a value that is smaller than a predetermined stroke amount or to the minimum value. The stroke amount of the intake valve VVL becomes smaller, and the ratio of the deviation between cylinders in the actual stroke amount increases with respect to that of the target stroke amount. Accordingly, the deviations in the amount of intake air in each cylinder 100 accordingly larger. This creates a state that is suitable for learning the learning value of the deviation GDEV (#i) between cylinders.

Subsequently, the process proceeds to step 106c, in which the setting of the suction valve INVVT is changed to the setting of the suction valve for learning KINVVT. The setting of the exhaust valve EXVVT is changed to the setting of the exhaust valve for learning KEXVVT. As in 14 shown, the setting of the intake valve for learning KINVVT and the setting of the exhaust valve for learning are set so that no valve between the intake valve 28 and the exhaust valve 29 overlaps. The opening period of the intake valve 28 is set between top dead center (TDC) to bottom dead center (BDC). As a result, the back flow of the combustion gas or the intake air can be avoided, and thus the intake air pulsation due to the back flow of the combustion gas or the intake air can be prevented, creating a state suitable for learning the learning value of the deviation GDEV (#i) between cylinders is.

The valve operating conditions for the throttle valve 15 , the intake valve 28 and the exhaust valve 29 are changed to the valve operating conditions for learning in the manner described above. The process then proceeds to step 106d, in which the in 7 shown routine for calculating the rate of deviation of the amount of intake air between cylinders, which is described in the first embodiment. The rate of deviation of the intake air amount DEV (#i) between cylinders is calculated based on the maximum value of the current air flow speed in each cylinder GAPEAK (#i). Then, the process proceeds to step 107, in which the rate of deviation of the intake air amount DEV (#i) between cylinders calculated in step 106d as a learning value of the deviation chung GDEV (#i) between cylinders is learned (saved). Other parts of processing are the same as processing in each 3 shown step as described in connection with the first embodiment.

In the second embodiment described above, as in the timing chart in FIG 15 are shown, the throttle opening TA, the lift amount of the suction valve VVL, the setting of the suction valve INVVT and the setting of the exhaust valve EXVVT are respectively in the period in which the condition for executing the deviation learning is satisfied and the deviation learning execution flag is ON changed in the valve operating conditions (KTA, KVVL, KINVVT, KEXVVT). The valve operating conditions (KTA, KVVL, KINVVT, KEXVVT) are for learning the deviations between cylinders and the deviation rate of the intake air amount DEV (#i) between cylinders calculated under these specific conditions as a learning value of the deviation GDEV (#i) suitable between cylinders. Accordingly, the accuracy of learning the learning value of the deviation GDEV (#i) between cylinders can be increased.

Third embodiment

With reference to 16 and 17 the third embodiment of the present invention will be described below. In the third embodiment, the routine for switching the in 16 Intake air amount control method shown executed. The control of the intake air quantity by controlling the variable intake valve is excluded, but is controlled by the throttle valve until the learning of the learning value of the deviation GDEV (#i) between cylinders is completed. The amount of intake air is controlled by controlling the variable intake valve after the learning of the learning value of the deviation GDEV (#i) between cylinders is completed.

In the 16 The routine shown to switch the intake air amount control method is activated in predetermined cycles (e.g., a 4 ms cycle). When this routine is activated, it is determined in step 501 whether or not the learning of the learning value of the deviation GDEV (#i) between cylinders is completed (whether the inter-cylinder deviation learning completion flag GXVVL is ON or not). If the learning of the differences between cylinders is not completed, the process proceeds to step 502, where the amount of intake air is excluded from control by controlling the variable intake valve, but is controlled by the throttle valve. In this control of the intake air amount by controlling the throttle valve, the intake air amount is controlled by changing the throttle valve opening TA based on the position of the accelerator pedal or the operating conditions of the engine. In this case, the stroke amount of the intake valve VVL is set to a predetermined value, such as. B. the maximum value (e.g. 10 mm).

If subsequently determined in step 501 is that Learning the learning value of the deviations GDEV (#i) between cylinders the process proceeds to step 503, in which the intake air quantity by controlling the changeable Intake valve is controlled. If the intake air volume by controlling of the changeable Intake valve is controlled, the intake air quantity is controlled, by the stroke amount of the intake valve VVL based on the position the accelerator pedal or engine operating conditions, while the deviations of the intake air quantity DEV (#i) between cylinders based on the deviation rate of the intake air amount DEV (#i) between cylinders that are corrected using the Learning value of the deviation GDEV (#i) between cylinders is estimated. In this case, the throttle valve opening TA is controlled so that the pressure in the intake pipe PM to a predetermined negative pressure (e.g. -5 kPa) is obtained to the noise to reduce the intake air pulsations.

In the third embodiment described above, as in the timing chart of FIG 17 shown, control of the intake air amount is inhibited by controlling the variable intake valve, but controlled by controlling the throttle valve before the learning value of the deviation GDEV (#i) between cylinders is completed (when the inter-cylinder deviation learning execution flag GXVLL is OFF) , In this structure, the accuracy of the intake air amount control can be ensured by controlling the intake air amount with the throttle valve until the learning of the learning value of the deviation GDEV (#i) between cylinders is completed. Therefore, the deterioration of the driving ability or the exhaust gas emission due to not learning the learning value of the deviation GDEV (#i) between cylinders can be avoided.

Subsequently, after the learning of the learning value of the deviations GDEV (#i) between cylinders is completed and the inter-cylinder deviation learning execution flag GXVVL is turned ON, the control of the intake air amount by controlling the variable intake valve is initiated. The control of the intake air amount by controlling the variable intake valve can be carried out while correcting the variations in the intake air amount between cylinders with a high degree of accuracy using the estimated rate of variation of the intake air amount DEV (#i) between cylinders in the state in which the variation rate of the intake air amount DEV (#i) between cylinders almost for the entire operating range can be estimated with a high degree of accuracy using the learning value of the deviations GDEV (#i) between cylinders. Here, the intake air amount can be controlled by controlling the changeable intake valve with a high degree of accuracy.

Fourth embodiment

In the first to third embodiments, the rate of deviation of the intake air amount DEV (#i) between cylinders is calculated using the current air flow rate GRFM by the air flow measuring device 14 is recorded. In the fourth embodiment of the present invention, which in 18 and 19 is shown, the rate of deviation of the intake air amount DEV (#i) between cylinders is calculated using the current intake pipe pressure PMAP, which is determined by the intake pipe pressure sensor 18 (Registration unit) is recorded.

During engine operation, as in 19 shown, the output of the intake manifold pressure sensor pulsates 18 (current intake manifold pressure PMAP) in synchronization with the pulsation of the output of the air flow measuring device 14 (current air flow rate GAFM), and the output of the intake pipe pressure sensor 18 becomes substantially a minimum value when the output (current air flow rate GAFM) of the air flow measuring device 14 (current intake manifold pressure PMAP) is the maximum value.

Accordingly, in the fourth embodiment, the routine for calculating the minimum value of the current intake pipe pressure in each cylinder 100 executed as in 18 is shown, the maximum value of the current intake pipe pressure PMPEAK (#i) in the period corresponding to the intake stroke of each cylinder 100 is obtained and the rate of deviation of the intake air amount DEV (#i) between cylinders is obtained using the minimum value of the current intake pipe pressure DMPEAK (#i).

In the in 18 shown routine for calculating the minimum value of the current intake manifold pressure in each cylinder 100 becomes - at the time of the A / D conversions (e.g. 4 ms cycles) of the outputs of the intake manifold pressure sensor 18 activated. If this routine is activated, it is determined in step 601 whether the current intake manifold pressure PMAP is that by the intake manifold pressure sensor 18 is detected, the minimum value is or not. This method of determining the minimum value is such that the actual value of the current intake pipe pressure PMAP is compared with the previous value, and it is determined whether or not the change direction of the current intake pipe pressure PMAP is reversed from decrease to increase.

If the current intake manifold pressure PMAP is determined in step 601 as the minimum value, the process continues to step 602, in which it is determined whether the count of the Crankshaft angle counter as CCRNK = 12 - 17 is or not (i.e. the period corresponding to the intake stroke of the first cylinder # 1). If CCRNK = 12-17, the process continues to step 603, in which the minimum value of the current Intake manifold pressure PMAP during the period corresponding to the intake stroke of the first cylinder # 1 as Minimum value of the current intake pipe pressure of the first cylinder # 1 PMPEAK (# 1) is determined.

If "No" is determined in step 602 and the count value of the crankshaft angle counter in step 604 as CCRNK = 6-11 is determined (i.e. the period corresponding to the suction stroke of the second Cylinder # 2), the process continues to step 605, in which the minimum value of the current Intake pipe pressure PMAP in the period corresponding to the intake stroke of the second cylinder # 2 as a minimum value of the current one Intake pipe pressure of the second cylinder # 2 PMPEAK (# 2) is determined.

If "No" is determined in steps 602 and 604 and the count value of the crankshaft angle counter in step 606 as CCRNK = 18-23 is determined (i.e. the period corresponding to the suction stroke of the third Cylinder # 3), the process continues to step 607, in which the minimum value of the current intake manifold pressure PMAP in the period corresponding to the intake stroke of the third cylinder # 3 as a minimum value of the current intake manifold pressure of the third cylinder # 3 PMPEAK (# 3) is determined.

If in all steps 602, 604 and 606 "No" is determined, i. i.e. when the count value of the crankshaft angle counter CCRNK = 0-5 (the period corresponding to the intake stroke of the fourth cylinder # 4), the process continues to step 608, in which the minimum value of the current Intake pipe pressure PMAP in the period corresponding to the intake stroke of the fourth cylinder # 4 as a minimum value of the current one Intake pipe pressure of the fourth cylinder # 4 PMPEAK (# 4) is determined.

Using the minimum value of the current intake pipe pressure in each cylinder PMPEAK (#i) obtained as described above, the rate of deviation of the intake air amount becomes DEV (#i) for each cylinder 100 calculated according to the same method as the rate of deviation of the intake air quantity between cylinders (see 7 ) as described in connection with the first embodiment.

Even in the fourth embodiment, described above, the rate of deviation of the intake air amount DEV (#i) calculated between cylinders with a high degree of accuracy become.

Fifth embodiment

In the in 20 Fifth embodiment of the present invention shown taking into account such a property that the pressure in the cylinder 100 with the amount of intake air taken up in the cylinder, the pressure in each cylinder 100 is detected and the maximum value of the pressure in the cylinder 100 in the period over the compression TDC of each cylinder 100 is obtained. In order to achieve this process in the fifth embodiment, there is an in-cylinder pressure sensor 21a (Detection unit) for detecting the cylinder pressure for each cylinder. The cylinder pressure sensor 21a is in the spark plug 21 according to 1 built-in. The cylinder pressure sensor 21a however, can be separate from the spark plug 21 to be ordered.

In the fifth embodiment, the in 20 shown routine for calculating the maximum value of the in-cylinder pressure for each cylinder 100 at the times of the A / D conversions of the in-cylinder pressure sensor 21a (e.g. for 4 ms cycles). If this routine is activated, it is determined in step 701 whether the in-cylinder pressure CPS is determined by the in-cylinder pressure sensor 21a is detected, the maximum value is or not. This method of determining the maximum value may be such that the actual value of the cylinder internal pressure CPS is compared with the previous value, and it is determined whether or not the direction of change of the cylinder internal pressure CPS is inversely from increase to decrease.

If the in-cylinder pressure CPS is determined as the maximum value in step 701, the process proceeds to step 702, in which it is determined whether the count value of the crankshaft angle counter 22 ≤ CCRNK or CCRNK ≤ 3 (ie the period within 90 ° CA before and 90 ° CA after the compression TDC of the first cylinder # 1) or not. If the determination in step 702 is affirmative, the process proceeds to step 703, and the maximum value of the in-cylinder pressure CPS in the period within 90 ° CA before and 90 ° CA after the compression TDC of the first cylinder # 1 becomes the maximum value of the in-cylinder pressure of the first cylinder # 1 CPSPEAK (# 1).

If "No" is determined in step S702 and the count value of the crankshaft angle counter in step 704 as CCRNK = 16-21 is determined (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the second cylinder # 2), the process continues to step 705, and the maximum value of the in-cylinder pressure CPS in the period within 90 ° CA in front and 90 ° CA after the compression TDC of the second cylinder # 2 is called the Maximum value of the internal cylinder pressure of the second cylinder # 2 CPSPEAK (# 2) determined.

If "No" is determined in steps 702 and 704 and the count value of the crankshaft angle counter in step 706 as CCRNK = 4-9 is determined (i.e. in the periods within 90 ° CA before and 90 ° CA after the compression TDC of the third cylinder # 3), the process continues to step 707, and the maximum value of the in-cylinder pressure CPS in the period within 90 ° CA in front and 90 ° CA after the compression TDC of the third cylinder # 3 is called the Maximum value of the internal cylinder pressure of the third cylinder # 3 CPSPEAK (# 3) determined.

If in all steps 702, 704 and 706 "No" is determined, i. i.e. when the count value of the crankshaft angle counter as CCRNK = 10-15 is determined (in the period within 90 ° CA before and 90 ° CA after the compression TDC of the fourth cylinder # 4), the process continues to step 708, and the maximum value of the in-cylinder pressure CPS in the period within 90 ° CA in front and 90 ° CA after the compression TDC of the fourth cylinder # 4) is called the Maximum value of the cylinder pressure of the fourth cylinder # 4 CPSPEAK (# 4) certainly.

Using the maximum value of the cylinder internal pressure CPSPEAK (#i) for each cylinder 100 obtained as described above, the rate of deviation of the intake air amount DEV (#i) between cylinders for each cylinder 100 calculated in the same way as the method for calculating the rate of deviation of the amount of intake air between cylinders (see 7 ) as described in connection with the first embodiment.

The rate of deviation of the amount of intake air DEV (#i) between cylinders can also be high in the fifth embodiment Degree of accuracy can be calculated.

Sixth embodiment

With reference to the 4 . 8th and 21 to 28 the sixth embodiment of the present invention will be described below.

The execution of the respective routines for correcting the deviations between cylinders by the ECU 27 in the sixth embodiment will be described below.

Correction routine of deviations between cylinders

In the 8th shown routine for correcting the deviations between cylinders is in vorbe timed cycles while the engine is running. This routine is the same as in 8th shown steps described in the first embodiment, except for the start condition. If this routine is activated, it is determined in step 401 whether or not the condition for performing the inter-cylinder deviation correction is satisfied. The condition for performing the inter-cylinder deviation correction is to satisfy both of the following two conditions 1 and 2.

• 1. More than a predetermined period of time expired after the start operation (i.e., the engine is stopped after starting not in the unstable operating state).
• 2. The engine is not in the transitional mode (i.e. that is, the engine is in the steady operating state).

If both of these two conditions 1 and 2 fulfilled is the condition to execute the intermediate cylinder deviation correction is satisfied. However, if one or the condition is both of these conditions are not met to run the intermediate cylinder deviation correction is not met.

If it is determined that the condition to run the intermediate cylinder deviation correction is not fulfilled, the routine is completed without processing in relation to the inter-cylinder deviation correction from step 402 perform.

On the other hand, if it is determined that the condition to run the inter-cylinder deviation correction is satisfied in step 401, is the processing in relation to the inter-cylinder deviation correction from step 402 in the same manner as that described above first embodiment executed.

Main routine for calculation the area the intake air volume

In the 21 The main routine for calculating the area of the intake air amount shown is at times of A / D conversions of the output voltage of the air flow measuring device 14 executed (e.g. 4 ms cycles). If this routine is activated, it is determined in step 1201 whether the same condition of execution (condition for executing the inter-cylinder deviation correction) as in step 401 in FIG 8th is satisfied or not in this embodiment. If the condition for performing the inter-cylinder deviation correction is not satisfied, the routine is ended without executing the processing related to the calculation of the area of the intake air amount for a predetermined period from step 1202.

On the other hand, if it is determined that the condition for performing the inter-cylinder deviation correction in step 1201 is satisfied, the processing related to the calculation of the area of the intake air amount for a predetermined period from step 1202 is carried out as follows. In the first place, the output voltage VAFM after filtering the air flow measuring device 14 read in step 1202, and then the process proceeds to step 1203, in which the output voltage VAFM from the air flow meter 14 into the current air flow rate GAFM by the air flow measurement device 14 flows using the current air flow rate map GAFM in 4 is converted.

The process then continues to step 1204, in which the count value of the crank angle counter CCRNK is read.

Then in the next step 1205 the in 8th shown routine for calculating the area of the intake air amount in each cylinder 100 executed for the predetermined period to the area of the intake air amount (output waveform of the air flow measuring device 14 ) in each cylinder 100 to calculate GASUM (#i) for the predetermined period.

Routine for calculating the area of intake air quantity in each cylinder 100 for a predetermined period

The routine for calculating the area of the intake air amount GA in each cylinder 100 for a predetermined period as in 22 is a subroutine shown in step 1205 in FIG 21 is activated, and serves as an area calculation unit. When this routine is activated, the predetermined period P becomes for calculating the area of the intake air amount in each cylinder 100 (the area of the output waveform of the air flow measuring device 14 ) using the in 23 shown map calculated in step 1211. As in 24 Here, the predetermined period P is set to a period in which the intake air amount is hardly subject to the influence of the reflected wave from the intake air pulsation or the intake air influence of other cylinders, more specifically the period which is the maximum value of the output waveform (intake air amount) of the air flow measuring device 14 includes.

The map of the predetermined period P in 23 is used to calculate the predetermined period P using the engine speed NE and the intake air amount GA as parameters. The map is set in such a manner that the predetermined period P becomes longer when the amplitude of the pulse tion waves becomes larger in the area in which the engine speed NE is small or in the area in which the intake air amount GA is large.

After the predetermined period P is calculated, the process proceeds to step 1212, in which it is determined whether the current air flow rate GAFM is determined by the air flow meter 14 is determined, the maximum value is or not.

If it is determined in step 1212 that the current air flow amount GAFM is not the maximum value, the routine is ended without executing the subsequent processing. At the time when the current air flow rate GAFM subsequently reaches the maximum value, the process proceeds to step 1213, where it is determined whether the crank angle counter count CCRNK = 12-17 (ie, the period corresponding to the intake stroke of the first cylinder # 1 ) or not. If CCRNK = 12-17, the process proceeds to step 1214, in which the current air flow rate GAFM for the predetermined period P of the intake stroke of the first cylinder # 1 (the period within P / 2 before and P / 2 after time t) , in which the value becomes the maximum value) is integrated to obtain the area of the intake air quantity of the first cylinder GASUM (# 1). The current air flow rate data GAFM is stored in the RAM of the ECU 27 stored whenever the details in the predetermined sampling cycles (e.g., 4 ms cycles) are acquired in chronological order, and after the stored data of the current air flow rate GAFM for the predetermined period P and the area of the intake air quantity GASUM are integrated (# 1) is obtained, the stored data of the current air flow rate GAFM is deleted.

If "No" is determined in step 1213 and the count value of the crankshaft angle counter in step 1215 as CCRNK = 6-11 is determined (i.e. the period corresponding to the suction stroke of the second Cylinder # 2), the process continues to step 1216, in which the current air flow rate GAFM of the intake stroke of the second cylinder # 2 for the predetermined period P is integrated to the area of To obtain the intake air quantity of the second cylinder # 2 GASUM (# 2).

If "No" is determined in steps 1213 and 1215 and the count value of the crankshaft angle counter in step 1217 as CCRNK = 18-23 is determined (i.e. the period corresponding to the suction stroke of the third Cylinder # 3), the process continues to step 1218, in which the current air flow rate GAFM of the intake stroke of the third cylinder # 3 for the predetermined period P is integrated to the area the intake air volume of the third cylinder GASUM (# 3).

If in all steps 1213, 1215 and 1217 "No" is determined, i. i.e. when the count value of the crankshaft angle counter as CCRNK = 0 - 5 is determined (the period corresponding to the intake stroke of the fourth cylinder # 4), the process continues to step S1219, in which the current air flow rate GAFM of the intake stroke of the fourth cylinder # 4 for the predetermined period P is integrated to the area the intake air volume of the fourth cylinder GASUM (# 4).

Routine for calculation the rate of deviation of the amount of intake air between cylinders

In the 25 The routine shown for calculating the rate of deviation of the amount of intake air between cylinders is executed every cycle (every 180 ° CA in the case of the four-cylinder engine). The process is the same as the routine for calculating the rate of deviation of the intake air quantity between cylinders shown in the first embodiment, and serves as a calculation unit of the rate of variation of the intake air quantity between cylinders. When this routine is activated, the area of the intake air amount GA in each cylinder GASUM (#i) is read in step 1221, and the area of the intake air amount in each cylinder GASUM (#i) is adjusted between the cylinders in the next step 1222 by to obtain an adjustment value of the area of the intake air quantity GASUMSM (#i) for each cylinder. GASUMSM (#i) = GASUMSM (# i-1) + K1 × {GASUMMS (#i) - GASUMSM (# i-1)} In this equation, K1 is a matching coefficient, and GASUMSM (# i-1) is a matching value of the area of the intake air amount in the (# i-1) th cylinder.

The process then continues to step 1223, and the deviation rate of the intake air amount DEV (#i) between cylinders can for each cylinder can be calculated.

Equation 2

The denominator of the equation shown above is an average of the adjustment values of the areas of the intake air amounts GASUMSM (#i) for all cylinders, and K2 is a correction coefficient for converting deviations in the area of the intake air amount to the deviation of the intake air amount caused by the in 26 shown map is fixed. Accordingly, when the predetermined period P for calculating the area of the intake air amount of each cylinder GASUM (#i) becomes shorter, deviations in the area of the intake air amount GASUM (#i) decrease. Therefore, the correction coefficient K2 is set to become larger as the predetermined period P is shortened.

As is clear from Equation 2, the rate of deviation of the intake air amount is DEV (#i) between cylinders for each cylinder 100 a value obtained by dividing the adjustment value of the deviation rate of the intake air quantity between cylinders for each cylinder GASUMSM (#i) by the mean value of the adjustment values of the deviation rates of the intake air quantity DEV between cylinders for all cylinders and then multiplying by the correction coefficient K2.

The inter-cylinder intake air amount can be obtained by multiplying the rate of deviation of the intake air amount DEV (#i) between cylinders by the intake air amount GA (mean air flow rate) by the air flow measuring device 14 is grasped.

Referring to timing diagrams in 27 and 28 An embodiment of the inter-cylinder change correction in this embodiment will be described below.

In the period in which the condition for performing the inter-cylinder change correction is satisfied and the inter-cylinder change correction execution flag is turned ON, as in FIG 27 shown, the area of the intake air amount GASUM (#i) a predetermined period (the period within P / 2 before and P / 2 after the time t at which the current air flow rate GAFM takes the maximum value) for each intake stroke of each cylinder 100 is calculated and the area of the intake air amount of each cylinder GASUM (#i) is adjusted between the cylinders to obtain an adjustment value of the area of the intake air amount GASUMSM (#i) for each cylinder. In this way, the adjustment value of the area of the intake air quantity GASUMSM (#i) for each cylinder 100 divided by the mean of the adjustment values of the areas of the intake air quantities of all cylinders whenever the adjustment values of the areas of the intake air amounts GASUMSM (#i) are obtained for all cylinders (all 720 ° CA), and is then multiplied by the correction coefficient K2 by the To obtain the rate of deviation of the intake air amount DEV (#i) between cylinders for each cylinder.

As in 28 is shown whenever the deviation rate of the intake air amount DEV (#i) between cylinders for each cylinder 100 is calculated, the stroke correction amount FVVL (#i) is calculated according to the deviation rate of the intake air amount DEV (#i) between cylinders and the conditions of engine operation. Then the stroke correction quantity FVVL (#i) of the specified cylinder 100 every 180 ° CA to the mean value of the stroke quantities of the intake valves VVL of all cylinders added before the correction in order to obtain the final target stroke quantity of the suction valve VVLM.

In this way, the intake air quantity of each cylinder 100 corrected by the intake valve stroke amount with each intake stroke of each cylinder 100 is corrected according to the final target lift amount of the intake valve VVLM for each cylinder, which changes according to the intake stroke of each cylinder. This corrects the intermediate cylinder deviations in the intake air quantities.

Since according to the above sixth embodiment the predetermined period P for calculating the area of the intake air amount GASUM (#i) is set to the period that is the maximum value of the current Air flow rate GAFM includes the predetermined period P can be set to the period in which the amount of intake air hardly affects the influence of the reflected wave of the intake air pulsation or the intake air influence of others Cylinder is subject. Accordingly, the Deviation rate of the intake air quantity DEV (#i) between cylinders using the area the intake air quantity GASUM (#i) of each cylinder with a high degree of accuracy are calculated, and the deviations in the intake air volume between Cylinders can be corrected with a high degree of accuracy by the stroke amount of the intake valve using the rate of deviation of the intake air amount DEV (#i) between cylinders is corrected, causing both the Inter-cylinder deviations in torque and deviations in the air-fuel ratio can be reduced are.

Seventh embodiment

The predetermined period P for calculating the area of the intake air amount GASUM (#i) is set to the period including the maximum value of the current air flow rate GAFM in the sixth embodiment described above. In the in 29 to 32 The seventh embodiment shown is the predetermined period for calculating the area of the intake air amount GASUM (#i) to a valve opening period of the intake valve 28 set. As in 31 shown, the maximum point of the instantaneous air flow rate GAFM is in the valve opening period of the intake valve 28 if VVL is a positive value.

Since in this case there is a time delay from the time when the intake air that is in the intake pipe 12 flows through the air flow measuring device 14 occurs until the time when the intake air in the cylinder 100 is recorded (detection delay of the air flow measuring device 14 ), the detection delay of the air flow measuring device 14 is taken into account when setting the predetermined period for calculating the area of the intake air amount GASUM (#i) in the seventh embodiment.

In the seventh embodiment, the in 29 shown routine executed to the area of the intake air amount GASUM (#i) of each cylinder 100 to calculate in the following way. In step 1301, the detection delay DLY of the air flow measuring device 14 using an in 30 shown map calculated according to the current stroke amount of the intake valve VVL and the engine speed NE. The map in 30 is set in such a manner that the detection delay DLY becomes longer with the increase in the lift amount of the suction valve VVL in the low speed range. The flow rate of air in the cylinder 100 is reduced with the increase in the lift amount of the intake valve VVL in the low speed range.

After the detection delay DLY is calculated, the process proceeds to step 1302, in which it is determined whether it is the period of the detection delay DLY of the air flow measuring device 14 with respect to the valve opening period of the intake valve 28 (the period in which the intake valve opening flag is ON) or not. Here the valve opening period of the intake valve 28 may be determined based on the output of a stroke sensor (not shown) for detecting the lift amount of the intake valve VVL, or the control target value for the valve opening period may be used.

If this is not the period of detection delay DLY of the air flow measuring device 14 with respect to the valve opening period of the intake valve 28 corresponds to, the routine is ended without executing the subsequent processing. Then when it reaches the period which is the period of detection delay DLY of the air flow measuring device 14 with respect to the valve opening period of the intake valve 28 , the process proceeds to step 1303, in which it is determined whether or not the count value of the crank angle counter CCRNK = 12-17 (ie, the period corresponding to the intake stroke of the first cylinder # 1). If CCRNK = 12-17, the process proceeds to step 1304 in which the stored value of the area of intake air amount of the first cylinder GASUM (# 1) up to the previous time is integrated by the current instantaneous air flow rate GAFM to the stored one Renew the value of the area of the intake air volume of the first cylinder GASUM (# 1).

If "No" is determined in step 1303 and the count value of the crankshaft angle counter in step 1305 CCRNK = 6-11 (the period corresponding to the intake stroke of the second cylinder # 2 corresponds), the process continues to step 1306, in which the stored value of the area of the Intake air volume of the second cylinder GASUM (# 2) up to the previous one Timing by the current instantaneous air flow velocity GAFM is integrated to the stored value of the area of Renew intake air quantity of the second cylinder GASUM (# 2).

If "No" is determined in steps 1303 and 1305 and the count value of the crankshaft angle counter in step 1307 CCRNK = 18-23 (the period corresponding to the intake stroke of the second cylinder # 3) the process continues to step 1308, in which the stored value of the area of the Intake air volume of the third cylinder GASUM (# 3) up to the previous one Timing by the current instantaneous air flow velocity GAFM is integrated to the stored value of the area of Renew intake air quantity of the third cylinder GASUM (# 3).

If in steps 1303, 1305 and 1307 "No" is determined, i. i.e. when the count value of the crankshaft angle counter CCRNK = 0-5 (the period corresponding to the intake stroke of the fourth cylinder # 4 corresponds), the process continues to step 1309, in which the stored value of the area of the Intake air volume of the fourth cylinder GASUM (# 4) up to the previous one Point in time through the current instantaneous Air flow rate GAFM is integrated to the stored value of the area of Renew intake air quantity of the fourth cylinder GASUM (# 4).

According to the seventh embodiment, as in 32 is shown, the area of the intake air amount of each cylinder GASUM (#i) is renewed whenever the detection delay DLY of the air flow measuring device 14 from the time of completion of the valve opening period of the intake valve 28 every cylinder 100 has expired (time of completion of the ON period of the intake valve opening flag). Other parts of the processing are the same as those of the sixth embodiment.

The same effect as in the sixth embodiment can also be obtained in the seventh embodiment. Also, since the predetermined period for calculating the area of the intake air amount of each cylinder GASUM (#i) on the valve opening period of the intake valve 28 is set, it is not necessary to set the predetermined period for each operating area in the design and development stages, and therefore the number of adjustment steps can be advantageously reduced.

Eighth embodiment

In the 33 to 35 The eighth embodiment of the present invention shown is characterized in that the predetermined period for calculating the area of the intake air amount GASLTM (# 1) is set to a period in which the current air flow rate GAFM is larger than the average (see 34 ).

In the eighth embodiment, an in 33 shown routine is executed, and the area of the intake air amount for each cylinder GASUM (#i) is calculated as follows. In step 1301a, the air flow measuring device 14 sensed mean air flow rate GA read. The process then proceeds to step 1302a, in which it is determined whether or not the current air flow rate GAFM is greater than the average air flow rate GA.

If the current air flow rate GAFM is less than the mean air flow velocity GA, the routine is ended without executing the subsequent processing. If however, the current air flow rate GAFM is greater than the mean air flow velocity GA is the area the intake air volume for each cylinder GASUM (#i) according to the same Method calculated as described in the seventh embodiment (Steps 1303-1309).

According to the eighth embodiment described above, as in 35 shown, the area of the intake air amount for each cylinder GASUM (#i) is renewed whenever the period in which the current air flow rate GAFM of each cylinder ends 100 is greater than the mean. Other parts of the processing are the same as those of the sixth embodiment.

As in the eighth embodiment becomes the predetermined period for calculating the area of the Intake air quantity GASUM (#i) set to the period in which the current air flow velocity GAFM greater than is the mean so that they not necessarily to the predetermined period for everyone Operating area in the design and Development stages is set, as in the seventh embodiment, whereby the workload can be advantageously reduced.

Ninth embodiment

The area of the intake air amount of each cylinder GASUM (#i) for a predetermined period is calculated using the current air flow rate GAFM by the air flow measuring device 14 is determined in the sixth embodiment to eighth embodiment. In contrast, the ninth embodiment of the present invention is as shown in FIG 8th . 19 . 23 . 24 and 36 to 38 shown, characterized in that the current air flow rate GMAP using the current intake manifold pressure PMAP by the intake manifold pressure sensor 18 (Detection unit) is calculated, and the area of the intake air amount of each cylinder GASUM (#i) is calculated for a predetermined period using the current air flow rate GMAP.

During engine operation, as in 19 shown, the output of the intake manifold pressure sensor pulsates 18 in synchronization with the pulsation of the output (instantaneous air flow rate GAFM) of the air flow measuring device 14 , and the intake pipe pressure sensor output 18 (Current intake manifold pressure PMAP) is essentially a minimum value when the output (current airflow speed GAFM) of the airflow measurement device 14 is the maximum value.

The current intake manifold pressure PMAP, that of the intake manifold pressure sensor 18 can be converted into the current air flow velocity GMAP by the following nozzle equation.

Aν: Ansaugventil-Öffnungsfläche
κ: Verhältnis der spezifischen Wärme
ρ: Gasdichte
μ: Koeffizient der Strömungsgeschwindigkeit
Pa: Umgebungsdruck.Equation to calculate the current air flow rate GMAP (Equation 3, nozzle equation)

Aν: intake valve opening area
κ: ratio of specific heat
ρ: gas density
μ: coefficient of flow velocity
Pa: ambient pressure.

Therefore, by converting the output of the intake pipe pressure sensor 18 (Current intake manifold pressure PMAP) using the nozzle equation shown in the current air flow rate GMAP, the area of the intake air amount of each cylinder GASUM (#i) for a predetermined period can be calculated in almost the same approximation as in the sixth to eighth embodiments.

In the ninth embodiment, the area of the intake air amount of each cylinder GASUM (#i) for a predetermined period from the output of the intake pipe pressure sensor 18 to calculate the in 36 Main routine shown for calculating the area of the intake air amount at the times of the A / D conversions of the output of the intake pipe pressure sensor 18 executed (e.g. in 4 ms cycles). If the routine is activated, it is determined in step 1401 whether the same condition for performing the inter-cylinder deviation correction as in step 401 in FIG 8th is fulfilled or not (see the two conditions 1 . 2 in the sixth embodiment). If the condition for performing the inter-cylinder deviation correction is not satisfied, the routine is ended without executing the processing related to the calculation of the area of the intake air amount for a predetermined period from step 1402.

On the other hand, if it is determined that the condition for performing the inter-cylinder deviation correction in step 1401 is satisfied, the processing related to the calculation of the area of the intake air amount for a predetermined period from step 1402 is carried out as follows. In step 1402, the output voltage becomes VMAP after filtering from the intake manifold pressure sensor 18 read and the process proceeds to step 1403 in which the output voltage VMAP from the intake manifold pressure sensor 18 in the current intake manifold pressure PMAP around the intake manifold pressure sensor 18 using the current intake manifold pressure PMAP in 37 is converted.

Then the process proceeds to step 1404, in which the current intake manifold pressure PMAP using equation 3 shown above into the current air flow rate GMAP by the intake manifold pressure sensor 18 flows, is converted. After reading the count value of the crank angle counter CCRNK in the next step 1405, the process proceeds to step 1406 in which the routine for calculating the area of the intake air amount of each cylinder 100 for a predetermined period as in 24 shown is performed to calculate the area of the intake air amount of each cylinder GASUM (#i) for a predetermined period in the following manner.

As in 38 In step 1411, the predetermined period P is used to calculate the area of the intake air amount of each cylinder 100 (Area of current air flow velocity GMAP) using the in 23 shown map calculated. Here, the predetermined period P is set to a period in which the intake air amount is hardly subject to the influence of the reflected wave of the intake air pulsation or the air intake influence of other cylinders. More specifically, it is determined at a period that includes the maximum value of the current air flow rate GMAP (the minimum value of the current intake pipe pressure PMAP) that is output from the intake pipe pressure sensor 18 is converted (current intake manifold pressure PMAP).

In the next step 1412 it is determined whether the current air flow rate GMAP, which is converted from the current intake manifold pressure PMAP, the maximum value is or not. The maximum value can be determined by determining whether the direction of change the current air flow velocity GMAP from the increase reversed to the reduction or not, e.g. B. by comparison the actual value of the current air flow velocity GMAP with the previous value.

If the current air flow rate GMAP at step 1412 is not the maximum value, the routine becomes completed without following the steps below. After that goes at the moment when the current air flow velocity GMAP has reached the maximum value, the process proceeds to step 1413, in which it is determined whether the count value of the crankshaft angle counter CCRNK = 12-17 (i.e., the period corresponding to the intake stroke of the first cylinder #1). If CCRNK = 12-17 the process continues to step 1414, in which the current air flow rate GMAP for the predetermined period P of the intake stroke of the first cylinder # 1 (the period within P / 2 before and P / 2 after time t, in which chem the value becomes the maximum value) is integrated to the area of the Intake air volume of the first cylinder GASUM (# 1).

If "No" is determined in step 1413 and the count value of the crankshaft angle counter in step 1415 CCRNK = 6-11 is determined (i.e. the period corresponding to the suction stroke of the second Cylinder # 2), the process continues to step 1416, in which the current air flow rate GMAP for the predetermined period P of the intake stroke of the second cylinder # 2 integrated will increase the area of the Intake air volume of the second cylinder GASUM (# 2).

If "No" is determined in steps 1413 and 1415 and the crank angle counter count is determined in step 1418 CCRNK = 18-23 (ie, the period corresponding to the intake stroke of the third cylinder # 3), the process proceeds to step 1418 which integrates the current air flow rate GMAP for the predetermined period P of the intake stroke of the third cylinder # 3 to get the area of the intake air amount of the third cylinder GASUM (# 3).

If in all steps 1413, 1415 and 1417 "No" is determined, i. H. the count value of the crankshaft angle counter CCRNK = 0-5 is determined (i.e. the period corresponding to the suction stroke of the fourth Cylinder # 4), the process continues to step 1419, in which the current air flow rate GMAP for the predetermined period P of the intake stroke of the fourth cylinder # 4 is integrated to the area the intake air volume of the fourth cylinder GASUM (# 4). Other parts of the processing are the same as in the sixth Embodiment.

In the ninth described above embodiment can the same effects as in the sixth embodiment can be obtained.

Tenth embodiment

In the ninth embodiment, the predetermined period P for calculating the area of the intake air amount GASUM (#i) is set to a period including the maximum value of the current air flow rate GMAP (the minimum value of the current intake pipe pressure PMAP). In the tenth embodiment of the present invention, which in 39 however, the predetermined period for calculating the area of the intake air amount GASUM (#i) is set to a period that is delayed with respect to the valve opening period of the intake valve 28 by the detection delay DLY of the intake pipe pressure sensor, similarly to the case of the seventh embodiment.

In the tenth embodiment, an in 39 shown routine is executed, and the area of the intake air amount for each cylinder GASUM (#i) is calculated as follows. First, the detection delay DLY of the intake pipe pressure sensor 18 in accordance with the actual stroke quantity of the intake valve VVL and the engine speed NE in step 1501 using the map in 30 calculated in step 1501.

Then the process proceeds to step 1502, in which it is determined whether this is the period of the detection delay DLY of the intake manifold pressure sensor 18 with respect to the valve opening period of the intake valve 28 corresponds or not. If this is not the period of the detection delay DLY of the intake pipe pressure sensor 18 with respect to the valve opening period of the intake valve 28 corresponds to, the routine is ended without executing the subsequent processing.

If this is the period corresponding to the period of the detection delay DLY of the intake pipe pressure sensor 18 with respect to the opening period of the suction valve 28 , the process proceeds to step 1503, in which it is determined whether the count value of the crank angle counter CCRNK = 12-17 (ie, the period corresponding to the suction stroke of the first cylinder # 1). If CCRNK = 12-17, the process proceeds to step 1504, in which the stored value of the area of intake air amount of the first cylinder GASUM (# 1) up to the previous time is integrated by the current current air flow rate GMAP to the stored one Value GASUM (# 1) to renew.

If "150" is determined in step 1503 and the count value of the crankshaft angle counter in step 1505 as CCRNK = 6-11 is determined (the period corresponding to the intake stroke of the second Cylinder # 2), the process continues to step 1506, in which the stored value of the area of the Intake air volume of the second cylinder GASUM (# 2) up to the previous one Timing by the current instantaneous air flow velocity GMAP is integrated to renew the stored value GASM (# 2).

If "No" is determined in steps 1503 and 1505 and the count value of the crankshaft angle counter in step 1507 as CCRNK = 18-23 is determined (the period corresponding to the suction stroke of the third Cylinder # 3), the process continues to step 1508, in which the stored value of the area of the Intake air volume of the third cylinder GASUM (# 3) up to the previous one Timing by the current instantaneous air flow velocity GMAP is integrated to renew the stored value GASM (# 3).

If in all steps 1503, 1505 and 1507 "No" is determined, i. i.e. when the count value of the crankshaft angle counter CCRNK = 0-5 is determined (the period corresponding to the intake stroke of the fourth cylinder # 4), the process continues to step 1509, in which the stored value of the area of the Intake air volume of the fourth cylinder GASUM (# 4) up to the previous one Timing by the current instantaneous air flow velocity GMAP is integrated to renew the stored value GASM (# 4).

According to that described above tenth embodiment can have the same effect as in the seventh embodiment be achieved.

Eleventh embodiment

In the 40 shown eleventh embodiment of the present invention is characterized in that a predetermined period for calculating the area of the intake air amount GASUM (#i) is set to the period in which the current air flow rate GMAP is larger than the average as in the eighth embodiment.

In the eleventh embodiment, an in 40 shown routine is executed, and the area of the intake air amount for each cylinder GASUM (#i) is calculated as follows. At step 1501a, the average air flow rate GA is read by the air flow measurement device 14 is recorded. Then, the process proceeds to step 1502a, in which it is determined whether or not the current air flow rate GMAP calculated from the current intake pipe pressure PMAP is higher than the average air flow rate GA.

If the current air flow rate GMAP is less than the mean air flow velocity GA, the routine is completed without the subsequent processing perform. If however, the current air flow rate is higher than GMAP the mean air flow velocity GA is the area the intake air quantity GASUM of each cylinder (#i) according to the same processing (Steps 1503 to 1509) as calculated in the tenth embodiment. Other Parts of the processing are the same as those of the sixth embodiment.

Also in the one described above eleventh embodiment the same effect as in the eighth embodiment can be obtained.

In the ninth through eleventh embodiments described above, the output of the intake pipe pressure sensor 18 (the current intake pipe pressure PMAP) is converted into the current air flow rate GMAP to calculate the area of the intake air amount of each cylinder GASUM (#i) for a predetermined period, and then the rate of deviation of the intake air amount DEV (#i) between cylinders is calculated from the area of the Intake air volume of each cylinder GASUM (#i) calculated. However, it is also possible to output (the current intake manifold pressure PMAP) of the intake manifold pressure sensor 18 for a predetermined period to integrate the area of the intake manifold pressure of each cylinder 100 for a predetermined period and then calculate the rate of deviation of the intake air amount DEV (#i) between cylinders from the area of the intake pipe pressure area of each cylinder.

Twelfth embodiment

In the 41 to 47 The twelfth embodiment of the present invention shown is characterized in that the internal cylinder pressure increases with the increase in the amount of intake air received in the cylinder. Therefore, the cylinder pressure inside each cylinder 100 is detected and the area of the detected waveform of the in-cylinder pressure is obtained for a predetermined period. To achieve this process, in the twelfth embodiment is an in-cylinder pressure sensor 21a (Detection unit) for detecting the cylinder internal pressure for each cylinder is arranged, as in the fifth embodiment described above.

In general, the waveform of the in-cylinder pressure is as in 45 shown such that the internal cylinder pressure increases with the compression of the air introduced into the cylinder before the ignition, but after the ignition the maximum value (peak value) of the internal cylinder pressure after the ignition is significantly greater than the pressure when the cylinder 100 is simply filled with air, since the internal pressure suddenly increases due to the combustion pressure. It also moves even when the amount of air entering the cylinder 100 is filled, is equal to, the maximum value of the cylinder internal pressure after the ignition according to the amount of fuel or the combustion state up and down. Therefore, it is difficult to estimate the amount of air flowing into the cylinder from the maximum value of the in-cylinder pressure after the ignition 100 is filled.

In the twelfth embodiment, the predetermined period for calculating the area of the detected waveform of the cylinder pressure is set to the time before the ignition. However, as in 46 shown, non-combustion occurs in the cylinder during the fuel cut-off operation or the starting operation (in the non-combustion). Since the maximum value of the in-cylinder pressure is the maximum compression pressure of the air filled in the cylinder, the area of the detected waveform of the in-cylinder pressure is calculated in the period including the maximum value of the in-cylinder pressure (the period before and after the compression TDC).

In the twelfth embodiment, the main routine for calculating the area of the cylinder pressure as in FIG 41 shown, at times of the A / D conversions (e.g. in cycles of 4 ms) of the in-cylinder pressure sensor 21a executed. If this routine is activated, it is determined in step 1601 whether the condition for performing the inter-cylinder deviation correction in step 401 in FIG 8th is fulfilled or not (see the two conditions 1 . 2 in the sixth embodiment). If the condition for performing the inter-cylinder deviation correction is not satisfied, the routine is ended without executing the processing related to the calculation of the area of the in-cylinder pressure for a predetermined period from step 1602.

On the other hand, if it is determined that the condition for performing the inter-cylinder deviation correction in step 1601 is satisfied, the processing related to the calculation of the area of the in-cylinder pressure for a predetermined period from step 1602 is carried out in the following manner. The output voltage VCPS (#i) of the in-cylinder pressure sensor 21a every cylinder 100 after filtering, read in step 1602. Then the process proceeds to step 1603, in which the output voltage VCPS (#i) of the in-cylinder pressure sensor 21a using an in 42 shown map is converted into the cylinder internal pressure CPS (#i).

The process then proceeds to step 1604, in which the count value of the crankshaft angle counter CCRNK is read. In the next step 1605, it is determined whether or not it is in the fuel cut mode or in the cranking mode (non-combustion). If it is not in the fuel cut mode or in the cranking mode, the process proceeds to step 1606, in which a routine for calculating the area of the in-cylinder pressure of each cylinder 100 is carried out for a predetermined period during the combustion. The routine is further described below with reference to FIG 43 described. On the other hand, if it is in the fuel cut mode or in the cranking mode, the process proceeds to step 1607 and the routine for calculating the area of the in-cylinder pressure of each cylinder 100 for a predetermined period during the non-combustion is carried out. The routine is further described below with reference to FIG 44 described.

If the routine to calculate the area of the cylinder pressure of each cylinder 100 is activated for a predetermined period during the combustion in step 1606, a predetermined period P is calculated in step 1611 for calculating the area of the in-cylinder pressure of each cylinder, as in FIG 43 is shown. During combustion, as in 45 shown, the predetermined period P is set to the time before the ignition. The length of the predetermined period P is calculated according to a map or the like according to the engine speed NE and the intake air amount GA. In this case, it is set so that the predetermined period P becomes longer as the amplitude of the pulsation wave becomes larger in the area in which the engine speed NE is low or in the area in which the intake air amount GA is large.

In the next step 1612, it is determined whether it is an ignition timing or not. If it is not the ignition timing, the routine is ended without executing the subsequent processing. If it is the ignition timing, the process then proceeds to step 1613, where it is determined whether the crank angle counter count 22 ≤ CCRNK or CCRNK ≤ 3 or not (ie, the period within 90 ° CA before and 90 ° CA after the compression TDC of the first cylinder # 1). If the determination in step 1613 is affirmative, the process proceeds to step 1614, in which the stored data of the cylinder pressure CPS (# 1) of the first cylinder # 1 is integrated for the predetermined period P before the ignition of the first cylinder # 1, to get the area of the cylinder pressure of the first cylinder CPSSUM (# 1). The cylinder pressure data of each cylinder CPS (#i) becomes cylinder by cylinder in the RAM of the ECU 27 stored in chronological order in each predetermined sampling cycle. Then, the stored data of the cylinder pressure of each cylinder CPS (#i) for the predetermined period P before the ignition of each cylinder 100 integrated to acquire the area of the cylinder pressure CPSSUM (#i) of each cylinder, and then the stored data of the cylinder pressure of each cylinder CPS (#i) is deleted.

If "No" is determined in step 1613 and the count value of the crankshaft angle counter in step 1615 as CCRNK = 16-21 is determined (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the second cylinder # 2), the process continues to step 1616, in which the cylinder internal pressure of the second Cylinder # 2 for the predetermined period P before the ignition of the second cylinder # 2 CPS (# 2) is integrated to the area of the cylinder pressure of the second cylinder CPSSUM (# 2).

If "No" is determined in steps 1613, 1615 and the count value of the crankshaft angle counter as CCRNK = 4-9 is determined (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the third cylinder # 3), the process continues to step 1618, in which the cylinder internal pressure of the third Cylinder # 3 CPS (# 3) for the predetermined period P before the ignition of the third cylinder # 3 is integrated to the area the cylinder pressure of the third cylinder CPSSUM (# 3).

If in all steps 1613, 1615 and 1617 "No" is determined, i. i.e. when the count value of the crankshaft angle counter as CCRNK = 10-15 is determined (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the fourth cylinder # 4), the process continues to step 1619, in which the cylinder internal pressure of the fourth Cylinder # 4 CPS (# 4) for the predetermined period P before the fourth cylinder fires is integrated to the area of the cylinder pressure of the fourth cylinder CPSSUM (# 4).

On the other hand, a routine for calculating the area of the in-cylinder pressure of each cylinder 100 for a predetermined period during the non-combustion ( 44 ) in step 1607 in 41 initiated so that a predetermined period P for calculating the area of the in-cylinder pressure of each cylinder 100 in the event of no combustion (during the fuel cut-off operation or the starting operation) in step 1621 is calculated. If the combustion is stopped, as in 46 shown, the predetermined period P is set to a period including the maximum value. The length of the predetermined period P is calculated according to a map or the like according to the engine speed NE and the intake air amount GA. In this case, it is set so that the predetermined period P becomes longer as the amplitude of the pulsation wave becomes larger in the area in which the engine speed NE is low or in the area in which the intake air amount GA is large.

In the next step 1622, it is determined whether, the in-cylinder pressure CPS (#i) by the in-cylinder pressure sensor 21a is detected, the minimum value is or not. The method for determining the maximum value is such that the actual value of the in-cylinder pressure CPS (#i) is compared with the previous value and it is determined whether or not the change direction of the in-cylinder pressure CPS (#i) is reversed from increase to decrease.

If the cylinder pressure CPS (#i) is not the maximum value, the routine is completed without carry out the subsequent processing. If the CPS internal pressure (#i) with the maximum value reached, the process continues to step 1623, in which it is determined whether the count of the Crankshaft angle counter than 22 ≤ CCRNK or CCRNK ≤ 3 is or not (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the first cylinder # 1). If the provision in If step 1623 is positive, the process proceeds to step 1624 in which the cylinder internal pressure CPS (# 1) of the first cylinder # 1 for the predetermined period within 90 ° CA before and 90 ° CA after the compression TDC of the first cylinder # 1 (i.e. the period within P / 2 before and P / 2 after the time t at which the maximum value exists) to the area the cylinder internal pressure of the first cylinder CPSSUM (# 1).

If "No" is determined in step 1623 and the count value of the crankshaft angle counter in step 1625 as CCRNK = 16-21 is determined (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the second cylinder # 2), the process continues to step 1626, in which the cylinder pressure CPS (# 2) for the predetermined period P around the compression TDC of the second cylinder # 2 is integrated to the area the cylinder internal pressure of the second cylinder CPSSUM (# 2).

If "No" is determined in steps 1623, 1625 and the count value of the crankshaft angle counter in Step 1627 as CCRNK = 4-9 is determined (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the third cylinder # 3), the process continues to step 1628, in which the cylinder pressure CPS (# 3) for the predetermined period P around the compression TDC of the third cylinder # 3 is integrated to the area the cylinder pressure of the third cylinder CPSSUM (# 3).

If in all steps 1623, 1625 and 1627 "No" is determined, i. i.e. when the count value of the crankshaft angle counter as CCRNK = 10-15 is determined (i.e. the period within 90 ° CA before and 90 ° CA after the compression TDC of the fourth cylinder # 4), the process continues to step 1629, in which the cylinder pressure CPS (# 4) for the predetermined period P around the compression TDC of the fourth cylinder # 4 is integrated to the area of the cylinder pressure of the fourth cylinder CPSSUM (# 4).

An embodiment of the inter-cylinder deviation correction of the twelfth embodiment described above is described below using an in FIG 47 shown timing diagram explained.

In the period in which the condition to run of the inter-cylinder deviation correction is satisfied, the inter-cylinder deviation correction execution flag is ON. The area of the cylinder internal pressure of each cylinder CPSSUM (#i) for the predetermined one Period is for calculated each compression stroke of each cylinder, and then the area of the cylinder internal pressure of each cylinder CPSSUM (#i) between the Cylinders in the same manner as in the sixth embodiment adjusted to an adjustment value of the area of the cylinder internal pressure to obtain each cylinder CPSSUMSM (#i). That way any adjustment value of the area of the CPSSUMSM (#i) by the mean adjustment value of the areas of the cylinder internal pressure all cylinders divided. The calculation is always carried out when the adjustment value of the area of the cylinder internal pressure of each cylinder CPSSUMSM (#i) (720 ° CA) becomes. The value obtained is with the correction coefficient K2 multiplied by the deviation rate of the intake air quantity DEV (#i) to get between cylinders. Other parts of the processing are same as that of the sixth embodiment.

In the twelfth embodiment described above can have the same effect as in the sixth embodiment be achieved.

In the twelfth embodiment, the area of the in-cylinder pressure CPSSUM (#i) for a predetermined period becomes from the output waveform of the in-cylinder pressure sensor 21a calculated for each cylinder. The rate of deviation of the intake air amount DEV (#i) between cylinders of each cylinder is calculated from the area of the cylinder internal pressure of each cylinder CPSSUM (#i). However, it is also possible to check the cylinder pressure CPS (#i) by the cylinder pressure sensor 21a every cylinder 100 is detected to convert to the current air flow rate and then the area of the intake air amount each cylinder 100 to calculate for a predetermined period. Then, the rate of deviation of the intake air amount DEV (#i) between cylinders is calculated from the area of the intake air amount of each cylinder.

In the embodiments described above from the first to the twelfth embodiment the present invention is applied to the system in which the amount of intake air is controlled by controlling the variable intake valve becomes. However, the present invention is also applicable to the system in which only the intake air volume is controlled by the throttle valve becomes.

Especially in the embodiment from the first to the twelfth embodiment in the system in which the intake air quantity is only through the throttle valve is controlled, the amplitude of the intake air pulsation in the High load area larger. In the high-load area, the throttle valve is fully open or significantly open, and therefore the characteristic values (the maximum value, the minimum value, the area and the like) of the intake air pulsation can be determined easily. Therefore, it is recommended the learning value of the intermediate cylinder deviations to learn in this high load area.

The scope of the present invention is not limited to the four-cylinder engine, but is limited to the Multi-cylinder engine with five or more cylinders or three or fewer cylinders applicable.

The procedure for calculating the Deviation rate between cylinders is changeable if required. It is important to note the value of the intermediate cylinder deviations on the Basis of at least one of the sizes, the maximum value, the minimum value, the mean, amplitude, area and track length of each predetermined Period of intake air quantity, intake pipe pressure and cylinder pressure, to calculate.

When the present invention is applied to the variable valve mechanism having a structure in which the suction valve 28 every cylinder 100 driven by an electromagnetic actuator, the lift amount of the intake valve of each cylinder 100 corrected by the control amount of the electromagnetic actuator of each cylinder 100 is corrected for each cylinder according to the final target lift amount of the intake valve VVLM, so that the intake air amount of each cylinder 100 is corrected.

Other various changes and modifications are considered to be within the scope of the present invention falling as defined in the appended claims.

A deviation rate (DEV) of an intake air amount (GAFM) between cylinders is calculated and as a learning value (GDEV) based on an output of an air flow measuring device ( 14 ) learned when a predetermined condition is met. The predetermined condition is set as a preferred condition for learning the rate of deviation between cylinders. Subsequently, the rate of deviation between cylinders is estimated based on the learning value if the predetermined condition is not met. Therefore, deviations between cylinders of an internal combustion engine ( 11 ) is obtained precisely in almost all operating areas, so that the measurement of the amount of intake air between cylinders is achieved with a high degree of accuracy.

Claims (25)

Intermediate cylinder intake air quantity detection device for an internal combustion engine ( 11 ) with internal combustion with a variety of cylinders ( 100 ), the intermediate cylinder intake air quantity detection device comprising: a detection unit with at least one of the devices, an air flow measuring device ( 14 ) for detecting an amount of intake air (GAFM) that is in an intake pipe ( 12 ) flows, a pressure sensor ( 18 ) for detecting a pressure PMAP in the intake pipe ( 12 ) and a cylinder pressure sensor ( 21a ) for detecting a cylinder internal pressure CPS, characterized by : - an intermediate cylinder deviation learning unit ( 105 - 107) for calculating the deviation rate of the intake air amount DEV (#i) between cylinders or the inter-cylinder intake air amounts based on an output of the detection unit (VAFM, VMAP, VCPS) and learning the calculated value DEV (#i) as a learning value of Inter-cylinder deviations GDEV (#i) in the operating range in which a condition for executing the deviation learning is satisfied, and - an inter-cylinder deviation estimation unit ( 111 ) to estimate the deviation rate of the intake air amount DEV (#i) between cylinders or the inter-cylinder intake air amounts according to a current operating range using the learning value of the inter-cylinder deviations GDEV (#i) in the operating range in which the condition for performing the deviation learning is not satisfied. Inter-cylinder intake air amount detection device according to claim 1, the condition to execute learning to deviate during at least one of the operating modes, a fuel cut-off mode and a start-up company, Fulfills is. Inter-cylinder intake air amount detection device according to claim 1 or claim 2, wherein the condition for performing the deviation learning while operation at reduced speed is satisfied. Inter-cylinder intake air quantity detection device according to one of claims 1 to 3, the condition for executing the deviation learning Fulfills is when an engine speed NE is less than a predetermined speed and the intake air amount GAFM is larger than a predetermined amount is. Inter-cylinder intake air amount detection device according to one of claims 1 to 4, further comprising: - an intake valve ( 28 ) which is on an inflow side of the cylinder ( 100 ) is arranged to an air-fuel mixture in the cylinder ( 100 ) - an exhaust valve ( 29 ) on the downstream side of the cylinder ( 100 ) for blowing combustion gas out of the cylinder ( 100 ) is arranged, and - a throttle valve ( 15 ) in the intake pipe ( 12 ) to control the intake pipe ( 12 ) flowing intake air amount GAFM is arranged, the intermediate cylinder deviation learning unit ( 105 - 107 ) the operating conditions of at least one of the valves, the intake valve ( 28 ), the exhaust valve ( 29 ) and the throttle valve ( 15 ) in the period in which the learning value of the inter-cylinder deviations GDEV (#i) is learned in the operating range in which the condition for performing the deviation learning is satisfied changes to a predetermined operating condition. The inter-cylinder intake air amount detection device according to claim 5, wherein the inter-cylinder deviation learning unit ( 105 - 107 ) the opening of the throttle valve ( 15 ) changes to a fully opened state or an opening degree in which the intake pipe pressure PMAP is near the ambient pressure to learn the learning value of the inter-cylinder deviations GDEV (#i) in the operating range in which the condition for performing the deviation learning is satisfied , The inter-cylinder intake air amount detecting device according to claim 5 or claim 6, wherein the inter-cylinder deviation learning unit ( 105 - 107 ) the stroke volume of the intake valve ( 28 ) to at least a predetermined stroke amount or less and a minimum value to learn the learning value of the inter-cylinder deviation GDEV (#i) in the operating range in which the condition for performing the deviation learning is satisfied. The inter-cylinder intake air amount detection device according to one of claims 5 to 7, wherein the inter-cylinder deviation learning unit ( 105 - 107 ) changes the settings of the intake valve and the exhaust valve to the valve overlap between the intake valve ( 28 ) and the exhaust valve ( 29 ) during an opening period of the intake valve ( 28 ) in an area between a top dead center of the internal combustion engine ( 11 ) with internal combustion and a bottom dead center of the internal combustion engine ( 11 ) is defined with internal combustion to learn the learning value of the inter-cylinder deviation GDEV (#i) in the operating range in which the condition for performing the deviation learning is satisfied. The inter-cylinder intake air amount detection device according to any one of claims 5 to 8, further comprising: a changeable intake valve mechanism ( 30 ) with the suction valve ( 28 ) is provided to a stroke amount of the intake valve ( 28 ), and - a unit for controlling the variable intake valve mechanism ( 30 ) to control the amount of intake air GAFM. The inter-cylinder intake air amount detection device according to claim 9, wherein the inter-cylinder deviation estimation unit ( 111 ) the rate of deviation of the intake air amounts DEV (#i) between cylinders or the inter-cylinder intake air amount corresponding to an actual lift amount of the intake valve VVL using the learning value of the inter-cylinder deviations GDEV (#i) estimated by the inter-cylinder deviation learning unit ( 105 - 107 ) is learned, the stroke amount of the intake valve GVVL when the learning value of the intermediate cylinder deviations GDEV (#i) is learned, and the actual stroke amount of the intake valve VVL. An inter-cylinder intake air amount detection device according to claim 9 or claim 10, further comprising: - a unit to control the intake air amount GAFM through the variable intake valve mechanism ( 30 ) during a period in which the learning value of the inter-cylinder deviations GDEV (#i) by the inter-cylinder deviation learning unit ( 105 - 107 ) is learned, wherein the intake air amount GAFM is controlled by the throttle valve during a period in which the learning value of the inter-cylinder deviations GDEV (#i) is controlled by the inter-cylinder deviation learning unit ( 105 - 107 ) is learned, and the intake air amount GAFM is controlled by the variable intake valve mechanism upon completion of the learning of the learning value of the inter-cylinder deviations GDEV (#i). Intermediate cylinder intake air quantity detection device for an internal combustion engine ( 11 ) with internal combustion with a variety of cylinders ( 100 ), the intermediate cylinder intake air quantity detection device comprising: a detection unit with at least one of the devices, an air flow measuring device ( 14 ) for detecting an amount of intake air GAFM that is in an intake pipe ( 12 ) flows, a pressure sensor ( 18 ) for detecting an intake pipe pressure PMAP in the intake pipe ( 12 ) and a cylinder pressure sensor ( 21a ) for detecting a cylinder internal pressure CPS, characterized by: - an intermediate cylinder deviation learning unit ( 105 - 107 ) to calculate the deviation rate of the intake air amount DEV (#i) between cylinders or the inter-cylinder intake air amounts and to learn the calculated value as a learning value of the inter-cylinder deviation GDEV (#i) based on the output of the detection unit (VAFM, VMAP, VCPS) and - a unit to control the intake air amount GAFM through the variable intake valve mechanism ( 30 ) during a period in which the learning value of the inter-cylinder deviations GDEV (#i) by the inter-cylinder deviation learning unit ( 105 - 107 ) is learned, wherein the intake air amount GAFM is controlled by the throttle valve during a period in which the learning value of the inter-cylinder deviations GDEV (#i) is controlled by the inter-cylinder deviation learning unit ( 105 - 107 ) is learned, and the intake air amount GAFM is controlled by the variable intake valve mechanism upon completion of the learning of the learning value of the inter-cylinder deviations GDEV (#i). The inter-cylinder intake air amount detection device according to claim 1, wherein the detection unit detects the intake pipe pressure PMAP and the inter-cylinder deviation learning unit ( 105 - 107 ) learns the learning value of the intermediate cylinder deviations GDEV (#i) on the basis of a minimum value of the intake manifold pressure PMAP. The inter-cylinder intake air amount detection device according to claim 1, wherein the detection unit detects the in-cylinder pressure CPS and the inter-cylinder deviation learning unit ( 105 - 107 ) learns the learning value of the inter-cylinder deviations GDEV (#i) on the basis of a maximum value of the in-cylinder pressure CPS. Intermediate cylinder intake air quantity detection device for an internal combustion engine ( 11 ) with internal combustion with a variety of cylinders ( 100 ), the intermediate cylinder intake air quantity detection device comprising: a detection unit with at least one of the devices, an air flow measuring device ( 14 ) for detecting an amount of intake air GAFM that is in an intake pipe ( 12 ) flows, a pressure sensor ( 18 ) for detecting the intake pipe pressure PMAP in the intake pipe ( 12 ) and a cylinder pressure sensor ( 21a ) for detecting an internal cylinder pressure CPS, characterized by: - an area calculation unit ( 1211 - 1219 ) for calculating the area of the intake air amount GASUM (#i) of the output waveform of the detection unit (VAFM, VMAP, VCPS) for a predetermined period P for each intake stroke and each compression stroke of each cylinder (#i), - an inter-cylinder intake air amount deviation calculation unit ( 1221 - 1223 ) to calculate the deviation rate of the intake air amount DEV (#i) between cylinders or the inter-cylinder intake air amounts according to the area of the intake air amount GASUM (#i) for the predetermined period P of each cylinder (#i). Intermediate cylinder intake air quantity detection device according to claim 15, wherein - the detection unit detects at least one of the quantities, the intake air quantity GAFM and the intake pipe pressure PMAP, and - the area calculation unit ( 1211 - 1219 ) sets the predetermined period P to a period in which the intake air quantity GAFM hardly influences an reflected wave from an intake air pulsation or an air intake influence of other cylinders ( 100 ) is subject. The inter-cylinder intake air amount detection device according to claim 16, wherein the area calculation unit ( 1211 - 1219 ) sets the predetermined period P to at least one period with a maximum value GAPEAK (#i) of the intake air quantity GAFM and one period with the minimum value of the intake pipe pressure PMAP. The inter-cylinder intake air amount detection device according to claim 16 or claim 17, wherein the area calculation unit ( 1211 - 1219 ) the predetermined period P to a valve opening period of the intake valve ( 28 ) sets. Intermediate cylinder intake air quantity detection device according to one of claims 16 to 18, wherein the detection unit detects the intake air quantity GAFM and the area calculation unit ( 1211 - 1219 ) sets the predetermined period P taking into account a detection delay DLY of the detection unit. The inter-cylinder intake air amount detection device according to claim 16 or claim 17, wherein the detection unit detects the intake air amount GAFM and the area calculation unit ( 1211 - 1219 ) sets the predetermined period P to at least one of the periods, a period in which the intake air amount GAFM is equal to or larger than an average value GA, and a period in which the intake pipe pressure PMAP is less than an average value. 18. The inter-cylinder intake air quantity detection device according to claim 16, wherein the detection unit detects the intake pipe pressure PMAP and the area calculation unit ( 1211 - 1219 ) calculates the area of the intake air quantity GASUM (#i) and converts the intake pipe pressure PMAP, which is recorded by the detection unit, into the intake air quantity GAFM. The intermediate cylinder intake air amount detection device according to claims 16 to 18, wherein the detection unit detects the intake pipe pressure PMAP and the area calculation unit ( 1211 - 1219 ) sets the predetermined period P taking into account a detection delay DLY of the detection unit. The inter-cylinder intake air amount detection device according to claim 16 or claim 17, wherein the detection unit detects the intake pipe pressure PMAP and the area calculation unit ( 1211 - 1219 ) sets the predetermined period P to a period in which an intake air amount converted from the intake pipe pressure GMAP is larger than an average value of the intake air amount converted from the intake pipe pressure GMAP. The inter-cylinder intake air amount detection device according to claim 15, wherein the detection unit detects the in-cylinder pressure CPS and the area calculation unit ( 1211 - 1219 ) sets the predetermined period P to the time before the ignition. The inter-cylinder intake air amount detection device according to claim 24, wherein the area calculation unit ( 1211 - 1219 ) sets the predetermined period P to a period having a maximum value of the in-cylinder pressure CPS during one of the modes, a fuel cut-off mode and a cranking mode.