JPH05195831A - Suction and exhaust valve operation state detecting device for internal combustion engine - Google Patents

Abstract

PURPOSE:To surely detect the switching operation state of a valve stopping mechanism by calculating the rotation speed changing quantity of a cam shaft based on the rotation variation quantity of the cam shaft and judging whether or not cut-off cylinder switching is completed speed on the deviation between the displacement quantity and a specified criterion. CONSTITUTION:Pairs of rocker arms 3a and 3b and rocker arms 4a and 4b for opening and closing the suction and exhaust valve of an internal combustion engine 1 are rotatably and detachably supported by suction and exhaust rocker shafts 7 and 8 respectively, and suction and exhaust cams 5 and 6 are formed in a cam shaft 9 in a body. In this case, valve stopping mechanism M, which can stop the opening and closing operation of the suction and exhaust valve at required time, are attached to the rocker arms 3a and 4a respectively. On the other hand, the rotation variation quantity of the cam shaft, which is detected by a cam shaft rotation sensor 16, and other various pieces of information relating to running are input in an ECU 24 controlling each injector 25. In addition, in the ECU 24, the rotation speed variation quantity of the cam shaft is calculated based on the rotation variation quantity of the cam shaft, and whether or not cut-off cylinder switching is completed is judged based on the deviation quantity between the rotation speed variation quantity of the cam shaft and a specified criterion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on an internal combustion engine capable of performing a cylinder deactivation operation of a set cylinder by stopping only the intake and exhaust valves of the cylinder of the internal combustion engine set at a proper time. The present invention relates to an intake / exhaust valve operating state detection device for an internal combustion engine, which can accurately detect the operating state of a valve.

[0002]

2. Description of the Related Art During operation of an internal combustion engine, a valve stop mechanism that can stop cylinder operation by stopping intake and fuel supply to some cylinders in order to reduce output and reduce fuel consumption in a timely manner. Internal combustion engines equipped with this are known. When the control means for controlling the valve stop mechanism of this kind of internal combustion engine enters into the set operating range based on various operating information, the opening / closing operation of the intake / exhaust valves of the deactivated cylinders is stopped and the fuel to the deactivated cylinders is stopped within the operating range. When the supply is stopped and the set operating range is departed, the opening / closing operation of the intake / exhaust valves of the deactivated cylinders is returned to the normal state, and the fuel supply to the deactivated cylinders is restarted. In the valve stop mechanism used here, when returning from cylinder deactivation operation to normal operation, the injector drive is restarted together with the intake / exhaust valve of the cylinder that was stopped, but at this time, in the current system, the intake / exhaust valve After switching the valve stop mode to the valve drive mode, the injector drive is automatically restarted after a certain waiting time has passed,
It is configured to return to the all-cylinder operating state.

[0003]

However, when returning from the cylinder deactivation operation to the normal operation, the switching actuator of the valve stop mechanism automatically operates in response to the command to switch the intake / exhaust valve to the valve drive, and the cam is operated. There is no problem if the intake / exhaust valve can smoothly resume its opening / closing operation in conjunction with the shaft rotation. However, in some cases, the switching may not be performed properly, and the intake / exhaust valve may not normally open / close even if the switching actuator operates when returning from the cylinder deactivation operation to the normal operation. Conversely, when switching from the normal operation to the cylinder deactivation operation, a state may occur in which the intake / exhaust valve does not smoothly stop its opening / closing operation.

In the current system, even when the switching from the cylinder deactivation operation to the normal operation is not properly performed in this way, it is considered that the normal switching has been performed, and the injector drive is automatically performed after a certain waiting time. I will restart it. If such a state occurs, the fuel stays in the intake port of the deactivated cylinder, increasing the possibility of backfire or afterfire of the engine. On the contrary, if the switching from the normal operation to the cylinder deactivation operation is not properly performed and the injector drive is automatically stopped after a certain waiting time, the exhaust gas reaches an excessive lean and the catalyst deteriorates.

As described above, if any one of the intake and exhaust valves causes a switching failure, improper fuel injection may cause damage to the engine body or catalyst deterioration, which is a problem. ing. An object of the present invention is to provide an intake / exhaust valve operating state detection device for an internal combustion engine, which can accurately detect the switching operating state of the valve stop mechanism.

[0006]

In order to achieve the above-mentioned object, a first invention is a valve stopping means for stopping at least one of intake and exhaust valves of a cylinder of an internal combustion engine, and a cam of the internal combustion engine. Camshaft rotational displacement amount detecting means for issuing shaft rotational displacement amount information, camshaft speed fluctuation calculating means for calculating camshaft rotational speed fluctuation amount based on the camshaft rotational displacement amount information, and camshaft speed fluctuation amount And a predetermined determination value based on a deviation between the cylinder deactivation switching determination means and a cylinder deactivation switching determination means that issues cylinder deactivation switching determination information.

A second aspect of the present invention is a valve stop means for stopping at least one of intake and exhaust valves of a set cylinder of an internal combustion engine,
Camshaft drive torque detection means for issuing drive torque information applied to the camshaft of the internal combustion engine; camshaft drive torque fluctuation calculation means for calculating a fluctuation amount of camshaft drive torque based on the camshaft drive torque information; The present invention is characterized by further comprising cylinder deactivation switching determination means for determining whether or not cylinder deactivation switching is completed based on a deviation between the shaft drive torque and a predetermined determination value and issuing cylinder deactivation switching determination information.

[0008]

In the first aspect of the invention, the camshaft speed variation calculating means receives the camshaft rotational displacement amount information from the camshaft rotational displacement amount detecting means and calculates the camshaft rotational speed variation amount based on the information. Based on the deviation between the camshaft rotation speed fluctuation amount and the predetermined determination value, the cylinder deactivation switching determination means can determine whether or not the cylinder deactivation switching is completed, and issue the cylinder deactivation switching determination information.

In the second aspect of the invention, the camshaft drive torque fluctuation calculating means receives the camshaft driving torque information from the camshaft driving torque detecting means and calculates the fluctuation amount of the camshaft driving torque based on the information. Based on the deviation between the camshaft drive torque fluctuation amount and the predetermined determination value, the cylinder deactivation switching determination means can determine whether or not the cylinder deactivation switching is completed and issue the cylinder deactivation switching determination information.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The intake / exhaust valve operating state detecting device for an internal combustion engine of FIG.
Be attached to. The cylinder head 2 of the engine 1 is formed with an intake passage and an exhaust passage which are not shown and which can communicate with each cylinder, and each passage is opened and closed by an intake valve and an exhaust valve which are not shown. These intake and exhaust valves (not shown) are connected to the intake cam 5 via the rocker arms 3a, 3b, 4a and 4b.
And is driven to open and close by the exhaust cam 6. Here, the rocker arms 3a, 3b, 4a, 4b are pivotally supported by the intake / exhaust rocker shafts 7, 8, and the intake cam 5 and the exhaust cam 6 are integrally formed on the cam shaft 9.

A timing gear 11 is integrally attached to one end of the camshaft 9, and this timing gear is connected to a crankshaft side (not shown) via a timing belt 13 so that the rotation speed is half the engine rotation speed. It is configured to rotate the cam shaft 9. Here, a rotation detecting disk 14 is integrally attached to the end of the cam shaft 9 opposite to the timing gear 11, and a cam shaft rotation sensor 16 for issuing information on the rotational displacement amount of the cam shaft 9 is paired therewith. The disk 14 and the cam shaft rotation sensor 16 constitute an encoder. Incidentally, reference numerals 18 and 1 in FIG.
Reference numerals 9 and 20 denote bearings that support each shaft.

In FIG. 1, the second cylinder (# 2) and the third cylinder
The rocker arms 3b and 4b of the cylinder (# 3) can always open and close the intake and exhaust valves, and the rocker arms 3a and 4a that oppose the first cylinder (# 1) and the fourth cylinder (# 4) open and close the intake and exhaust valves at predetermined times. A valve stop mechanism M that can stop the engine is attached. It is well known that the valve stop mechanism M here moves the valve pressing piece (not shown) on each rocker arm 3a, 4a between the valve opposing position and the retracted position by the hydraulic pressure switching means to make the valve pressing operation of the rocker arm idle when the valve is stopped. Take the configuration of.

The hydraulic oil is supplied from the hydraulic circuit 23 to the hydraulic pressure switching means of the valve stop mechanism M here. The hydraulic circuit 23 receives the pressure oil sucked into and discharged from the valve stop mechanism M from the hydraulic pressure supply means 22 side through the cylinder deactivation electromagnetic valve 21. The hydraulic pressure supply means 22 comprises a hydraulic pump and an oil tank as shown in the figure. The cylinder shut-off solenoid valve 21 is a three-way valve, which supplies pressure oil to each valve stop mechanism M when it is on, switches the mechanism M to a valve stop and holds it, and eliminates pressure oil of each valve stop mechanism M when it is off. Then, the mechanism M is switched to valve drive and held, and is driven and controlled by an engine control unit 24 described later.

Further, an injector 25 for injecting fuel to an intake port (not shown) of each cylinder is mounted on the cylinder head 2 of FIG. received,
The injection drive control is performed by the engine control unit 2
Made by 4. The engine control unit (ECU) 24 has its main part formed by a microcomputer, and performs well-known control processing such as fuel supply control to the engine 1, ignition timing control, throttle valve drive control, and cylinder deactivation control. Accompanyingly, the cylinder switching control is performed. For this purpose the engine control unit 2
4, the rotation speed Ne of the engine 1 from the engine rotation sensor 30, the intake air amount A from the air flow sensor 31, the vehicle speed Sv from the vehicle speed sensor 32, and the camshaft 9 from the camshaft rotation sensor 16 via an FV converter (not shown). The rotational displacement amount θc, the unit crank angle signal Δθ from the crank angle sensor 33, the cylinder signal #n from the cylinder determination sensor 34, and various operation information such as throttle opening information and water temperature. ing.

Here, the engine control unit 24
Particularly has a function as a cam shaft speed fluctuation calculating means and a cylinder deactivation switching judging means. The camshaft speed fluctuation calculating means calculates the fluctuation amount hn of the camshaft rotational speed Vc based on the camshaft rotational displacement amount θc information. The cylinder deactivation switching determination means determines the camshaft speed fluctuation amounts hn, sn and the predetermined determination values h1, s.
Based on the deviation between 1 and h3, it is determined whether or not the cylinder deactivation switching is completed, and the cylinder deactivation switching determination information is issued. The operation of the intake / exhaust valve operating state detection device for the internal combustion engine of FIG. 1 will be described below with reference to the control program of the engine control unit 24 (see FIGS. 4 and 5) and the operation explanatory diagrams of FIGS. 2 and 3. The engine control unit 24 performs fuel injection control, ignition timing control, cylinder deactivation control, etc. according to a well-known control program along a main routine (not shown), and
At a predetermined point of time, the cylinder deactivation switching determination control process of FIG. 4 is performed, and the camshaft rotation speed fluctuation value calculation routine of FIG. 5 is performed at a time interrupt every unit time.

Here, in a well-known cylinder deactivation control routine (not shown), the cylinder deactivation processing of the first and fourth cylinders # 1 and # 4 is performed at a proper time, for example, during constant speed running with medium to low load.
At this time, it is assumed that the cylinder deactivation flag ICFLG has been switched, and initial setting such as clearing processing of each flag is performed in the main routine. When the cylinder deactivation switching determination control routine in FIG. 5 is reached, the latest camshaft speed fluctuation amount hn, data of the cylinder deactivation flag ICFLG as a cylinder deactivation command, and the like are fetched. Here, the camshaft rotation speed fluctuation value calculation routine of FIG. 5 will be described. Step b1 of the routine
At b2, the latest camshaft rotation speed Vcn is fetched, and it is further determined whether or not UPFLG (a flag which is considered to have reached the maximum point of symbol p1 in FIG. 2) is on, and when it is not on, that is, the minimum point. While it is after p2, the process proceeds to step b3, and when it reaches, the process proceeds to step b6.

At step b3, the previous camshaft rotation speed V
It is determined whether or not the current camshaft rotation speed Vcn is higher than c (n-1), and while it is large (while it is after the minimum point p2), the process proceeds to step b6. When it is equal or smaller, that is, the maximum point p1. Is reached, the process proceeds to step b4. Here, U
The PFLG is turned on to clear the LPFLG (a flag which is considered to have reached the minimum point of the symbol p2 in FIG. 2). Further, in step b5, the absolute value of the deviation from the previous minimum value VcLP of the camshaft rotation speed is calculated from the current camshaft rotation speed Vcn (value at p1), and the same value is used as the latest camshaft speed fluctuation amount h.
The value of the hn area is updated as n. When step b6 is reached, it is determined here whether or not LPFLG is on, and while it is not on, that is, while it is after the maximum point p1, step b
7 and when it reaches step b10.

At step b7, the previous camshaft rotation speed V
It is determined whether or not the camshaft rotation speed Vcn of this time is smaller than c (n-1), and while it is small (while it is after the maximum point p1), it proceeds to step b10, and when it is equal or larger, that is,
When the minimum point p2 is reached, the process proceeds to step b8. here,
Turn on LPFLG and clear UPFLG. Furthermore,
At step b9, the maximum value VcU of the latest camshaft rotation speed is obtained.
P is called, and the camshaft rotation speed Vcn (p
The value of the hn area is updated with the same value as the latest camshaft speed fluctuation amount hn.

Thereafter, when step b10 is reached, the camshaft rotation speed Vcn of this time is rewritten to the previous camshaft rotation speed Vc (n-1), and the process returns to the main routine. Cam shaft speed fluctuation amount h calculated in this way
n is taken in at step a1 of the cylinder deactivation switching control routine. Step a of the cylinder deactivation switching determination control routine
When it reaches 2, it is judged by the ICFLG whether or not the cylinder deactivation command is being output. If the cylinder deactivation is being performed, the process proceeds to step a4, and otherwise, the process proceeds to step a3.

In step a3, during the operation of all cylinders, the latest camshaft speed fluctuation amount hn is the all-cylinder operation determination value h1 (preset as camshaft speed fluctuation amount h1 at the normal camshaft rotation speed Vc in FIG. 2). Is determined, and if it is equal, that is, it is considered that the intake / exhaust valve is properly opening and closing, and one control cycle is ended. On the contrary, when the camshaft speed fluctuation amount hn is different from the all-cylinder operation determination value h1, it is considered that the intake / exhaust valve is not properly opened / closed and the switching is defective, and even during the all-cylinder operation. A command to stop the fuel supply to the first and fourth cylinders # 1 and # 4 is issued, the all-cylinder operation command is output to the cylinder deactivation electromagnetic valve 21 again, and the process proceeds to step a7. Here, it is again determined whether or not the camshaft speed fluctuation amount hn is equal to the all-cylinder operation determination value h1, and since it is not equal, steps a5 to a7 are repeated. If they are equal to each other, step a8 is reached, a fuel supply command is issued to the first and fourth cylinders # 1, # 4, and the process returns.

On the other hand, if the cylinder deactivation command is issued in step a2 and the process proceeds to step a4, the latest camshaft speed fluctuation amount hn is the cylinder deactivation operation determination value h2 (at the normal camshaft rotation speed Vc in FIG. 3). It is determined whether or not the camshaft speed fluctuation amount h2 is equal to the preset value), and if it is equal, that is, it is considered that the intake / exhaust valve properly holds the closed state, and one control cycle is ended. .. On the contrary, when the camshaft speed fluctuation amount hn is different from the cylinder deactivation operation determination value h2, the intake / exhaust valve does not properly maintain the closed state, and it is considered that switching is defective, and step a9 is performed.
Then, the all cylinder operation command is output to the cylinder deactivation solenoid valve 21 again. Further, the cam shaft speed fluctuation amount hn is determined by the cylinder deactivation operation determination value h2.
Is determined, and step a9 is performed until they are equal.
Through a10 are repeated, and when they are equal, the process returns to the main routine.

Here, the engine control unit 24
The injector drive processing performed by the above will be described with reference to FIG.
This injector drive routine is based on the unit crank angle signal Δ
It is executed for each interrupt of θ (pulse signal). here,
The target intake air amount A / N calculated by the engine speed Ne and other routines is fetched, and the process proceeds to step c3. Here, the main routine side obtains information as to whether or not the fuel is cut. If the fuel is cut, the process returns as it is, otherwise step c4 is reached. Here, the basic fuel pulse width Tf is calculated from the target intake air amount A / N, and then the target fuel pulse width Tinj, the basic fuel pulse width Tf, the air-fuel ratio correction coefficient KAF fetched from the main routine side, and the ambient temperature. And an atmospheric pressure correction coefficient KDT, an injector operation delay correction value TD, and the like.

When step c6 is reached, it is judged whether or not ICFLG = 1, which indicates that the cylinder is deactivated, and if no, that is, when the cylinder is not deactivated (all cylinder operation), the process proceeds to step c7.
Go to 8. At step c7, the current first and fourth cylinders #
It is determined whether or not a fuel supply cut command to 1 and # 4 is issued. If there is no fuel supply cut command, the process directly proceeds to step c9, and if it is issued, the process proceeds to step c8.

At step c9, the target fuel pulse width Ti is set to the driver for driving all the injectors 25 of the first to fourth cylinders.
nj is set, and when the cylinder is deactivated on the step c8 side, the target fuel pulse width Tinj is set only to the driver for driving the injectors 25 of only the two and three cylinders. Then, each driver is triggered to return. As a result, when the cylinder is suspended,
The injectors 25 of the 1st to 4th cylinders of the 2nd and 3rd cylinders, respectively, perform the injection drive at predetermined injection timings when the cylinders are not deactivated, and when switching all cylinders from the deactivated cylinders,
Switching all cylinders. Even if the all-cylinder operation command is issued before completion, fuel supply to the first and fourth cylinders # 1, # 4 is stopped, and fuel is supplied to the intake ports of the first and fourth cylinders # 1, # 4. It can stay and prevent the occurrence of backfire.

In the intake / exhaust valve operating state detecting device for an internal combustion engine shown in FIG. 1, a cylinder head 2 of the engine 1 is provided with one cam shaft 9 and intake / exhaust rocker shafts 7 and 8, but instead of this,
The first invention can also be applied to a DOHC-type engine (not shown) in which an intake valve is driven by a cam of an intake cam shaft and an exhaust valve is driven by an exhaust cam of an exhaust cam shaft. In this case, as shown in FIGS. 7 and 8, the maximum point p1 of the camshaft rotation speed Vic of the intake camshaft is set to the camshaft rotation speed fluctuation calculation routine of FIG. 9 similar to the camshaft rotation speed fluctuation calculation routine of FIG. The maximum value cycle Sn is calculated on the basis of the calculation routine.

Here, in the camshaft rotational speed variation calculation routine of FIG. 9, steps b5 and b9 are eliminated and b11 and b12 are added, as compared with FIG. Here, step b3 is reached from steps b1 and b2, and while the current camshaft rotation speed Vcn is higher than the previous camshaft rotation speed Vc (n-1) (while the camshaft rotation speed Vcn is after the minimum point p2), the process proceeds to step b6. , When the maximum point p1 is reached, the process proceeds to steps b4 and b11. At step b4, UPFLG is turned on and LPFL is turned on.
G (a flag which is considered to have reached the minimum point indicated by the symbol p2 in FIG. 7) is cleared. Further, in steps b11 and b12, the value of the counter of the cam angle θc is read, the camshaft speed fluctuation amount Sn of this time is read, the counter is cleared, and the process proceeds to step b6. In steps b6 to b10 (excluding step b9), LPFLG is turned on, and control processing is performed to clear UPFLG.

In this case, in the all-cylinder operation, the maximum value cycle S of the camshaft rotation speed Vcn of the intake camshaft (as well as the exhaust camshaft) is S.
1 is almost 1 of the maximum value period S2 during the cylinder deactivation operation (see FIG. 8).
/ 2. Therefore, in the cylinder deactivation switching determination control routine of FIG. 10, steps a11, a12, a13, and a14 are performed instead of steps a3, a4, a7, and a10 in the cylinder deactivation switching determination control of FIG. Here, the calculated maximum value cycle Sn and the camshaft speed fluctuation amounts S1 and S2 that are set according to the engine speed are compared to compare the camshaft speed fluctuation amounts S1 and S2. ,
The fuel supply to the fourth cylinders # 1, # 4 can be stopped, and conversely, the cylinder deactivation operation can be started and the decommission cylinder switching can be reliably issued.

FIG. 11 shows another embodiment of the present invention. In the engine 1a, the cylinder head 2a has intake / exhaust cam shafts 9a, 10a and intake / exhaust rocker arms 7a, 8a.
Will be installed. An intake valve is driven by the intake cam 5 of the intake cam shaft, and an exhaust valve is driven by the exhaust cam 6 of the exhaust cam shaft D
It is configured as an OHC engine. Each camshaft 9
Timing gears 11a and 12a are integrally attached to one end of a and 10a, and both timing gears are connected to a crankshaft side (not shown) via a timing belt 13 so that the rotation speed is half the engine rotation speed. Both cam shafts 9a and 10a are configured to rotate. Here, a disc 14 is integrally coupled to the vicinity of each timing gear 11a, 12a on each cam shaft 9a, 10a and the other end, and the cam shaft rotational displacement amount information of the angular cam shaft 9a, 10a is provided to each disc 14 by the cam shaft. A cam shaft rotation sensor 16 which emits as drive torque information is provided in pairs, and each pair of the disk 14 and the cam shaft rotation sensor 16 constitutes a cam shaft drive torque fluctuation amount detecting means.

In FIG. 11, each rocker arm 3a, 4
a is an integrally formed cantilever type, the second cylinder (# 2)
And the rocker arms 3b and 4b of the third cylinder (# 3) can always open and close the supply / discharge valves, and the first cylinder (# 1) and the fourth cylinder (# 3)
Each of the rocker arms 3a and 4a that opposes 4) is provided with a well-known valve stop mechanism Ma capable of stopping the opening / closing operation of the supply / discharge valve at a predetermined time. 11, the same reference numerals as those in FIG. 1 indicate the same members, and the duplicate description thereof will be omitted.

Here, the engine control unit 24
In particular, a has a function as a camshaft speed variation calculation means and a cylinder deactivation switching determination means. The camshaft speed fluctuation calculating means calculates the fluctuation amount hn of the camshaft rotational speed Vc based on the camshaft rotational displacement amount θc information. The cylinder deactivation switching determination means determines the camshaft speed fluctuation amounts hn, sn and the predetermined determination values h1, s.
Based on the deviation between 1 and h3, it is determined whether or not the cylinder deactivation switching is completed, and the cylinder deactivation switching determination information is issued.

The operation of the intake / exhaust valve operating state detecting device for an internal combustion engine shown in FIG.
4a control program (see FIGS. 14 and 15) and FIG.
2. The operation will be described with reference to FIG. The engine control unit 24a here has many control processing portions similar to those in FIG. 1, and therefore redundant description is omitted here.
Fuel injection control, ignition timing control, according to the main routine
Cylinder control, etc. is performed according to a well-known control program, and FIG.
When the cylinder deactivation switching determination control routine of No. 4 is reached, the latest camshaft drive torque fluctuation amount Tcn, the data of the cylinder deactivation flag ICFLG as the cylinder deactivation command, etc. are fetched in step a1.

Here, the camshaft drive torque fluctuation amount calculation routine of FIG. 15 will be described. In step b11 of the routine, the latest relative rotation angle difference Δθc between the pair of disks 14f and 14r is calculated, and the camshaft drive torque T corresponding to the same value is calculated.
cn is calculated and stored in a predetermined area. In addition, UPF
It is determined whether or not LG (a flag that considers that the maximum point of the symbol p1 in FIG. 10 has been reached) is on, and while it is not on, that is, while it is after the minimum point p2, the process proceeds to step b3, and when it reaches, step b6. Proceed to. At step b3, it is judged whether or not the camshaft drive torque Tcn of this time is larger than the camshaft drive torque Tc (n-1) of the previous time. , Becomes smaller,
That is, when the maximum point p1 is reached, the process proceeds to step b4. Here, UPFLG is turned on to clear LPFLG (a flag which is considered to have reached the minimum point of reference sign p2 in FIG. 2).
Further, in step b12, the camshaft drive torque Tc of this time
The absolute value of the deviation from the previous minimum value VcLP of the camshaft drive torque is calculated from n (the value at p1), and the same value is used as the latest camshaft drive torque fluctuation amount hn to update the value in the hn area.

When step b6 is reached, the LPF is determined here.
It is determined whether or not LG is on, and while it is not on, that is, while it is after the maximum point p1, the process proceeds to step b7, and when it reaches, the process proceeds to step b10. In step b7, it is determined whether or not the current camshaft rotation speed Tcn is smaller than the previous camshaft drive torque Tc (n-1). If it is smaller (while the maximum point p1 is present), the process proceeds to step b10 to see if it is equal. , When it reaches the minimum point p2, the process proceeds to step b8.
Here, the LPFLG is turned on and the UPFLG is cleared. Further, in step b13, the maximum value VcUP of the latest camshaft drive torque Tcn is called, the absolute value of the deviation from the current camshaft drive torque Tcn (value at p2) is calculated from the same value, and the same value is set to the latest camshaft. The value of the hn area is updated as the driving torque fluctuation amount hn.

Thereafter, when step b10 is reached, the camshaft drive torque Tcn of this time is rewritten to the previous camshaft rotation speed Tc (n-1), and the process returns to the main routine. The camshaft drive torque fluctuation amount hn calculated in this manner is used as the step a1 of the cylinder deactivation switching control routine.
Is taken in. When step a2 of the cylinder deactivation switching determination control routine is reached, it is determined whether or not the cylinder deactivation command is being output.
Judging by G, the process proceeds to step a16 when the cylinder is inactive, and otherwise proceeds to step a15 when all the cylinders are in operation.

In step a15, during the operation of all cylinders, the latest camshaft drive torque fluctuation amount hn is the all cylinder operation determination value h3.
(Predetermined as the camshaft drive torque variation amount h3 at the normal camshaft drive torque Tc in FIG. 12) is determined, and if it is equal, that is, the intake and exhaust valves are properly opened and closed. Look at it and finish one control cycle. On the contrary, when the camshaft drive torque fluctuation amount hn is different from the all-cylinder operation determination value h3, the intake / exhaust valve is not opened / closed properly, which is considered to be a switching failure, and it is during all-cylinder operation. Also issues a command to stop the fuel supply to the first and fourth cylinders # 1 and # 4, and outputs the all-cylinder operation command to the cylinder deactivation solenoid valve 21 again.
Proceed to 17. Here, again, the cam shaft drive torque fluctuation amount h
It is determined whether or not n is equal to the all-cylinder operation determination value h3, and since it is not equal, steps a5, a6, and a17 are repeated. If they are equal to each other, step a8 is reached, a fuel supply command is issued to the first and fourth cylinders # 1, # 4, and the process returns.

On the other hand, if the cylinder deactivation command is issued in step a2 and the process proceeds to step a16, the latest cam shaft drive torque fluctuation amount hn is calculated as the cylinder deactivation operation determination value h4 (the cylinder deactivation cam shaft drive torque in FIG. 13). It is determined whether it is equal to the variation amount h4 (value set according to the engine speed) in advance, and if it is equal, it is considered that the intake / exhaust valve is properly maintained in the closed state, and one control cycle To finish. On the contrary, when the camshaft drive torque fluctuation amount hn is different from the cylinder deactivation operation determination value h4, the intake / exhaust valve does not properly maintain the closed state, and it is considered that switching is not successful, and the process proceeds to step a9 to complete the operation. The cylinder operation command is output to the cylinder deactivation solenoid valve 21 again. Furthermore, the cam shaft drive torque fluctuation amount h
It is determined whether or not n is equal to the cylinder deactivation operation determination value h4, steps a9 and a18 are repeated until they are equal, and when they are equal, the process returns to the main routine.

The injector drive processing of FIG. 6 is similarly performed here, and when the first and fourth cylinders # 1 and # 4 are not in the cylinder deactivated state, all the injectors 25 of the first to fourth cylinders respectively inject at predetermined injection timings. While driving, when switching all cylinders from idle cylinders, all cylinders can be switched. Even if the all-cylinder operation command is issued before completion, fuel supply to the first and fourth cylinders # 1, # 4 is stopped, and fuel is supplied to the intake ports of the first and fourth cylinders # 1, # 4. It can be prevented from staying and generating backfire. In the above description, the engine 1 has four cylinders, but the present invention can be applied to an engine having other number of cylinders. Further, the number of cylinder deactivated cylinders is fixed to two, but the number of cylinder deactivated cylinders is variable. Is also good.

[0038]

As described above, in the first aspect of the invention, the variation amount h of the camshaft rotation speed is calculated based on the camshaft rotation displacement amount Vc information.
n is calculated, and based on the deviation between the cam shaft rotational speed fluctuation amount hn, sn and the predetermined judgment values h1, h2, s1, s2, it is judged whether or not the cylinder deactivation switching is completed, and the cylinder deactivation switching determination information is applied. It can be accurately emitted, for example, the switching operation state of the valve stop mechanism can be accurately detected, and the occurrence of engine backfire and the like can be prevented.

In the second invention, the camshaft drive torque Tc information is received, the camshaft drive torque fluctuation amount hn is calculated based on the information, and the camshaft drive torque fluctuation amount hn and the predetermined judgment values h3 and h4 are calculated. It is possible to determine whether or not the cylinder deactivation switching has been completed based on the deviation from the above, and to accurately issue the cylinder deactivation switching determination information. For example, it is possible to accurately detect the switching operation state of the valve stop mechanism, and It can prevent the occurrence of fire.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an intake / exhaust valve operating state detection device for an internal combustion engine as an embodiment of the present invention.

2 is an intake / exhaust valve operation mode and a camshaft velocity diagram for each cylinder when the internal combustion engine of FIG. 1 is operating in all cylinders.

3 is an intake / exhaust valve operation mode and a camshaft velocity diagram for each cylinder when the engine of FIG.

4 is a flowchart of a cylinder deactivation switching determination control routine executed by an ECU in the apparatus of FIG.

5 is a flowchart of a camshaft rotation speed fluctuation value calculation routine performed by an ECU in the apparatus of FIG.

6 is a flow chart of an injector drive routine executed by an ECU in the apparatus of FIG.

FIG. 7 is an intake / exhaust valve operating mode and a camshaft velocity diagram for each cylinder of an internal combustion engine according to another embodiment of the present invention, when the intake / exhaust valve operating state detection device operates in all cylinders of the engine.

FIG. 8 is an intake / exhaust valve operating mode and a camshaft velocity diagram for each cylinder when the engine is in the cylinder deactivated operation of the intake / exhaust valve operating state detection device for an internal combustion engine according to another embodiment of the present invention.

FIG. 9 is a flowchart of a cylinder deactivation switching determination control routine executed by an ECU in an intake / exhaust valve operating state detection device for an internal combustion engine as another embodiment of the present invention.

FIG. 10 is a flowchart of a camshaft rotational speed fluctuation value calculation routine that is executed by the ECU in the intake / exhaust valve operating state detection device for an internal combustion engine as another embodiment of the present invention.

FIG. 11 is an overall configuration diagram of an intake / exhaust valve operating state detection device for an internal combustion engine as another embodiment of the present invention.

12 is an intake / exhaust valve operation mode and a camshaft velocity diagram for each cylinder when all the cylinders of the engine in FIG. 9 are operating.

13 is an intake / exhaust valve operation mode and a camshaft velocity diagram for each cylinder when the internal combustion engine of FIG. 9 is in a cylinder deactivated operation.

FIG. 14 is a flowchart of a cylinder deactivation switching determination control routine executed by the ECU in FIG.

FIG. 15 is a flowchart of a camshaft drive torque fluctuation amount calculation routine executed by the ECU in FIG.

[Explanation of symbols]

 1 engine 2 cylinder head 3a rocker arm 3b rocker arm 5 cam 6 cam 9 cam shaft 14 disk 16 cam shaft rotation speed 21 electromagnetic switching valve 24 ECU 25 fuel injection valve M cylinder deactivation mechanism M1 cylinder deactivation mechanism hn cam shaft speed fluctuation amount Vcn cam shaft Rotation speed hn Cam shaft speed fluctuation amount sn Cam shaft speed fluctuation amount Tcn Cam shaft drive torque

Claims (2)

[Claims] 1. A valve stopping means for stopping at least one of intake and exhaust valves of a set cylinder of an internal combustion engine, a camshaft rotational displacement amount detecting means for issuing rotational displacement amount information of a camshaft of the internal combustion engine, and Camshaft speed fluctuation calculating means for calculating the fluctuation amount of the camshaft rotational speed based on the camshaft rotational displacement information,
An internal combustion engine comprising: a cylinder deactivation switching determination means for determining whether or not cylinder deactivation switching is completed based on a deviation between the camshaft speed variation amount and a predetermined determination value and issuing cylinder deactivation switching determination information. Intake / exhaust valve operating state detection device. 2. A valve stopping means for stopping at least one of intake and exhaust valves of a set cylinder of an internal combustion engine, a camshaft drive torque detecting means for issuing drive torque information applied to a camshaft of the internal combustion engine, and the cam. A camshaft drive torque fluctuation calculation means for calculating the fluctuation amount of the camshaft driving torque based on the shaft driving torque information, and whether or not the cylinder deactivation switching is completed based on the deviation between the camshaft driving torque fluctuation amount and a predetermined judgment value. An intake / exhaust valve operating state detection device for an internal combustion engine, comprising: a cylinder deactivation switching determination means for making a determination and issuing cylinder deactivation switching determination information.