JPH02173320A - Controller for engine - Google Patents

Abstract

PURPOSE:To compensate the change of an output torque due to the changeover of a valve timing at what controls variably the supercharging volume of a supercharger on the basis of a basic supercharging pressure control quantity in opposition to an engine operation condition, by correcting the basic supercharging pressure control quantity according to a supercharging pressure change rate. CONSTITUTION:A turbo charger 7 whose compressor portion 8 and turbine portion 12 are respectively provided at an air intake manifold 3 and an exhaust manifold 11, is constituted so that a supercharging volume may be variable by changing an exhaust gas flow passage cross sectional area to the turbine portion 12 by means of an actuator 18 on the basis of a basic supercharging pressure control quantity in opposition to an engine operation condition including an engine rotation speed. Also, a valve mechanism 14 is constituted so that a valve timing may be variable by controlling through a solenoid valve 16 and a changeover control valve 17 oil pressure generated by means of an oil pump 15 driven by an engine. In this instance, the change rate of the supercharging pressure is detected at all times, and an arrangement is so made that the above basic supercharging pressure control quantity is corrected according to the change rate of this supercharging pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an engine control device including a valve operation state switching device and a variable capacity supercharger.

<Prior art> Combustion can be achieved over a wider operating range by changing at least one of the operating angle and lift of the intake valve or exhaust valve provided for each cylinder, mainly in response to the engine rotation speed. A valve operating mechanism equipped with a valve operation state switching device that improves the filling efficiency of air-fuel mixture into a chamber has been proposed, for example, in Japanese Patent Application Laid-open Nos. 63 and 611.

On the other hand, the A/R in the exhaust gas passage that flows into the turbine wheel is changed using a flap or multiple vanes, making it possible to obtain the optimal boost pressure with high responsiveness over a wider operating range. Various capacity superchargers have been proposed in Japanese Unexamined Patent Publication No. 62-282128 and others.

According to such a variable capacity supercharger, the desired supercharging pressure corresponding to the operating state can be controlled relatively arbitrarily and accurately. By using it in conjunction with the engine, further improvements in engine performance can be expected.

<Problems to be Solved by the Invention> By the way, the characteristics of the output l/lux with respect to the engine speed generally draw a curve like a mountain. For example, in an engine that changes the valve operating state in two stages, The output characteristics are shaped like two curved lines stacked one on top of the other. Therefore, although the output can be shifted in the same direction over a wider engine speed range, it is impossible to avoid the occurrence of a torque valley at the intersection of the two output l/lux characteristic curves.

The present invention was made in order to improve these problems, and the main L1 CI; Another object of the present invention is to provide an engine control device that can further enhance output torque characteristics over the entire rotational speed range.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, a switching device for varying the valve operating state of at least one of an intake valve and an exhaust valve is provided. and a variable capacity supercharger, and a basic boost pressure control amount that switches the switching device in response to the engine operating condition including at least the engine rotational speed, and a basic boost pressure control amount corresponding to the engine operating condition including at least the engine rotational speed. and a control means for varying the supercharging capacity of the supercharger based on the basic supercharging pressure control by the control means in response to a rate of change in supercharging pressure generated by the supercharger. #i control device for an engine, characterized in that the basic boost pressure control amount is corrected by the control means in a state in which the switching device corresponds to at least a low speed operating range. or a switching device for varying the valve operating state of at least one of an intake valve and an exhaust valve, a variable capacity supercharger, and at least an engine rotation speed. The switching device is operated to switch in accordance with the operating state of the engine including at least the engine rotational speed, and the supercharging capacity of the supercharger is varied based on a basic boost pressure control amount corresponding to the operating state of the engine including at least the engine rotation speed. control means for controlling the engine speed and the rate of change in supercharging pressure generated by the supercharger by the controller stage in a state where the switching device corresponds to at least a low speed operating range; This is achieved by providing an engine control device characterized in that the basic boost pressure control amount is corrected based on the above.

<Function> In this way, the drop in output torque that occurs in the portion of the valve mechanism that switches the operating state can be automatically compensated for by correcting the supercharging pressure.

<Example> The present invention will be described in detail below with reference to a specific example with reference to the accompanying drawings.

FIG. 1 shows the overall configuration of an intake system and an exhaust system of an engine to which the present invention is applied. For example, an intake manifold 3 connected to an intake boat 2 of each cylinder in an engine body 1- consisting of an in-line four-cylinder engine includes an intake pipe 4, a throttle body 5, an intercooler 6, and a compressor for a variable displacement turbocharger 7. The section 8 and the air cleaner 9 are connected in this order. Furthermore, a turbine section 1-2 of a variable displacement turbocharger 7 and a catalytic converter 13 are connected to an exhaust manifold 11 connected to an exhaust port 1-0 of each cylinder.

A valve mechanism 14 for controlling the intake of air-fuel mixture into the combustion chamber of each cylinder and the discharge of combustion gas is configured to transfer hydraulic pressure generated by an oil pump 15 driven by the engine body 1 to a solenoid valve 16.
The valve timing can be varied step by step by controlling the switching control valve 17 and the switching control valve 17.

The variable capacity turbocharger 7 uses supercharging pressure P2 directly downstream of the compressor or intake negative pressure P2 directly downstream of the throttle valve.
The actuator 18 driven by the actuator B continuously changes the cross-sectional area of the exhaust gas flow path to the turbine section 12, thereby continuously varying the supercharging capacity of the compressor. The turbocharger 7 is cooled together with the intercooler 6 by a water pump 19 driven by the engine body 1 with cooling water that is recirculated through a radiator 20 that is separate from the engine cooling water.

On the other hand, this engine 1 is configured to variably control the fuel injection amount, valve timing, and supercharging pressure by an electronic control circuit 21.

The electronic control circuit 21 receives an oil pressure signal OP from a normally closed oil pressure switch 22 provided on the switching control valve 17, an 02 signal from an oxygen concentration sensor 23 provided on the exhaust manifold 11, and an oil pressure signal from an engine rotation sensor 24. Rotational speed signal NE, water temperature signal Tw from the cooling water temperature sensor 25 provided in the water jacket of the engine body 1, parking and neutral signal P-N in the shift L position of the automatic transmission 26, slot)/le body 5 Intake temperature signal TA from intake temperature sensor 27 provided in intake passage 4a on the downstream side and intake pressure signal PB1 from intake pressure sensor 28
Valve opening signal θ1□1 from throttle valve opening sensor 29
, a boost pressure signal P2 from the boost pressure sensor 30 provided in the intake passage 4b downstream of the compressor, and an atmospheric pressure sensor 31 provided in the intake passage 4c between the air cleaner 9 and the compressor 8 of the turbocharger 7. atmospheric pressure signal P
A and a traveling speed signal V from the vehicle speed sensor 32 are respectively input. Based on these input signals, the solenoid valve 16 for switching valve timing, the fuel injection valve 33 for injecting fuel into the intake port 2, and the supercharging system for driving the actuator 18 for changing the supercharging capacity. The operations of the electromagnetic valves 34 and 35 that respectively control the pressure P2 and the intake negative pressure P are controlled by output signals from the electronic control circuit 21, respectively.

Next, the valve train 14 will be explained with reference to FIG.

The engine to which the present invention is applied is a so-called DOHC engine in which the intake valve and exhaust valve are driven by separate camshafts, and each cylinder is provided with two intake valves and two exhaust valves. Since both valves have basically the same configuration, only the valve operating mechanism on the intake side will be described below.

The rocker shaft 40 fixed to the cylinder head has
For each cylinder, three rocker arms 41, 42, and 43 are pivotably supported adjacent to each other so as to be swingable and relative to each other in angular displacement. A camshaft 45 is rotatably supported on one of the rocker arms 41, 42, and 43 by a cam journal 44 formed in the cylinder head.

The camshaft 45 is integrally formed with a pair of low-speed cams 46a and 46b with a small operating angle and a small lift amount, and a single high-speed cam 47 with a large operating angle and a large lift amount. Two oil supply pipes 48 and 49 are provided on one side of the camshaft 45 to lubricate the sliding surfaces of the camshaft 45 and the cam and the rocker arm. Also, the first and twentieth cams are in sliding contact with the low speed cams 46a and 46b.
The two ends of the valve stems of the pair of intake valves 50a, 50b, which are normally biased in the valve-closing direction, are in contact with the free ends of the lever arms 41, 42. On the other hand, the first and second
The 30th lever arm 43, which is disposed between the zero lever arms 41 and 42 and slides into contact with the high-speed cam 47, has a lost motion spring (not shown) in contact with its lower end, so that the 30th lever arm 43 is always rotated in two directions (=J empowered.

A connection switching device 51 is built inside the first to thirtieth lever arms 41 to 43 that are adjacent to each other. This connection switching device 51 consists of guide holes provided inside each rocker arm and a switching pin that slides into these guide holes.

The 10th claw arm 41 has a first guide hole 52 with a bottom that opens on the 30th claw arm 43 side.
0, and a first switching pin 53 slides into this first guide hole 52. First guide hole 52
A hydraulic chamber 54 is defined at the bottom of the shaft, and this hydraulic chamber 54 includes an oil passage 55 installed inside the tenth lever arm 41 and an oil supply hole 56 opened on the circumference of the hollow rocker shaft 40. It communicates with an oil supply passage 57 provided inside the rocker shaft 40 via the rocker shaft 40 .

The 30th hook arm 43 has a second guide hole 58 having the same diameter and concentric with the first guide hole 52 in the rest position where the cam slipper slides on the base circle of the high speed cam 47. , and one end is connected to the first
A second switching pin 59 that is brought into contact with the switching pin 53 is slid into the interior thereof.

Similarly, a third guide hole 60 with a bottom is bored in the 20th hook arm 42, and a stopper pin 6 whose one end is in contact with the other end of the second switching pin 59 is slidably inserted into the third guide hole 60. There is.

The swivel pin 61 has its shaft portion 63 fitted into the guide sleeve 62 fitted into the bottom of the third guide hole 60.
Moreover, the bullet is always urged toward the 30th claw arm 43 side by the return spring 64.

These five first and second switching pins 53 are connected to the hydraulic chamber 54.
By moving the rocker arms 41 to 43 in the left-right direction in FIG. 2 with the action of the hydraulic pressure introduced into the holder and the biasing force of the return spring 64, the rocker arms 41 to 43 can be individually swung as shown in FIG. By straddling the five switching pins 53 between adjacent rocker arms, the rocker arms 41 to 43 are integrally connected, and both intake valves 50a and 50a are connected to each other.
It is possible to selectively switch between states in which the valves 50b can be driven to open at the same time.

A high-speed lubricant oil supply pipe 49 of the above-mentioned oil supply pipes is connected downstream of the oil supply passage 57 provided inside the rocker shaft 40 . This high-speed lubricating oil supply pipe 49 is provided with an ejection hole 65 at a position corresponding to the high-speed cam 47 for injecting lubricating oil in a shower style.

Further, the other low-speed lubricating oil supply pipe 48 is connected to a lubricating oil path 66 branched from the oil gear gallery. This low-speed lubricating oil supply pipe 48 includes each cam 46a, 46b,
A jet hole 67 for spraying lubricating oil in a shower-like manner is provided at a position corresponding to 47, and the lubricating oil is also supplied to the cam journal 44 via an oil passage 68.

On the other hand, the aforementioned switching control valve J-7 is installed in the cylinder head, and is driven to open by the oil pressure supplied via the solenoid valve 16, which is controlled to open and close according to the aforementioned control. It also incorporates a spool valve 70 which is normally urged to the closed position by six return springs.

When the spool valve 70 is in the upper closed position (the state shown in FIG. 2), an inlet port 72 is connected to the lubricating oil passage 66 via the oil filter 71, and an outflow is connected to the oil supply passage 57 in the rocker shaft 40. The port 73 communicates only through the orifice hole 74. At the same time, the drain port 73 communicates with the drain port 1 75 that opens into the upper space of the cylinder head, and the oil pressure in the oil supply path 57 becomes low.

Therefore, oil pressure is not supplied to the oil supply path 57, and each pin 53 and
59 is connected to the hydraulic chamber 54 side by the return spring 64 (
In the biased position, each rocker arm is driven separately by a corresponding cam for angular displacement relative to each other. In this case, the oil supplied from the oil pan 76 to the oil gear gallery by the oil pump 15 is supplied to the low-speed lubricating oil supply pipe 48 via the lubricating oil passage 66, and as described above, the oil is supplied to the oil supply pipe 48 for low-speed lubricating oil, and as described above, the oil is Lubricate the contact surfaces and cam journal 44.

When the spool valve 70 is switched to the lower open position, the inflow port 72 and the outflow ports 1-73 are connected to the spool valve 70.
0 through the annular groove 77, and the outflow port 7
3 and the drain port I/75 are cut off, and the lubricating oil path 6
Oil is force-fed from 6 to the oil supply path 57. As a result, when hydraulic pressure is supplied to the hydraulic chamber 54 of the tenth lever arm 41, the first and second switching pins 53 and 59 move against the biasing force of the return spring 64 to move the second guide hole 58 and the third
Each rocker arm 41
43 are integrally connected. At this time, the oil supplied to the oil supply passage 57 operates the connection switching device 51 of each cylinder, and is supplied into the high-speed lubricating oil supply pipe 49 via the downstream end of the oil supply passage 57, and is connected to the high-speed cam 47 and the 30th oil supply pipe 49. Lubricate the sliding surface with the claw arm 43.

The spool valve 70 described in ``2'' is moved to the open position against the Ima 1 force of the return spring 69 by pilot pressure manually applied to the upper end side of the spool valve 70 via a pilot oil path 78 branched from the inflow port 72. Can be switched. The above-mentioned normally closed solenoid valve 16 is connected to this pilot oil passage 7.
8, the energization of the solenoid of this solenoid valve 16 is controlled by the output signal from the electronic control circuit 21,
When the solenoid valve 16 is opened, the spool valve 70 is switched to the open position and the valve timing is switched to high-speed valve timing as described above, and when the solenoid valve 16 is closed, the spool valve 70 is switched to the closed position and the valve timing is switched to the high-speed valve timing. is switched to low speed valve timing.

The switching operation of the spool valve 70 is performed by a hydraulic switch 22 provided in the housing of the switching control valve 17 that detects the hydraulic pressure of the outflow port 73 and turns on when the pressure is low and turns off when the pressure is high.
Confirmed by.

Next, the variable capacity turbocharger 7 will be explained with reference to FIG. Since the compressor section 8 of this turbocharger 7 is basically the same as any known type of turbocharger, only the turbine section 12 will be specifically explained.

The turbine casing 80 of the turbocharger 7 has an annular scroll passage 8 whose cross-sectional area gradually decreases toward the downstream.
1, and an exhaust gas inlet 82 is opened in the tangential direction thereof. And at the center position of the scroll passage 81,
A turbine wheel 83 is disposed integrally with the shaft end of a turbine shaft coaxial with the compressor shaft.

Inside the scroll passage 81, four fixed vanes 84 having a partially arcuate shape are formed integrally with the turbine casing 80 on a circumference concentric with the turbine wheel 83, with equal widths and equal intervals. These fixed vanes 84 divide the scroll passage 81 into an outer circumferential path 85 and an inner circumferential path 86 .

Between the fixed vanes 84 adjacent to each other, the fixed vanes 84
and four movable vanes 87 forming a partial arc shape with a substantially concave curvature.
are arranged on the same circumference as the fixed vane 84. These movable vanes 87 are each pivoted at a position adjacent to one circumferential end of the corresponding fixed vane 84 so as to be able to tilt only inward of the aforementioned circumference, and are in a fully closed state. Both vanes 84 and 87 form a substantially continuous airfoil shape. The inclination angle of the movable vane 87 is continuously variably controlled by a movable vane drive control device to be described later.

The movable vane drive control device controls the pivot shaft 88 of the movable vane 87.
A lever member 89 integrally extends from the lever member 89, and a pair of lever members 89 having slits 90 cut at both ends thereof to engage with the free ends of the two lever members 89, and pivotally supported to be able to swing freely. The seesaw member 91 has one end connected to the pivot shaft 92 of each seesaw member 91, and the other end is connected to one link rod 9.
3 and an actuator 18 as a drive source for the movable vane 87. This actuator 18 has a drive shaft 95 that reciprocates in the axial direction with fluid pressure.
It is connected to the link rod 93 via a connecting shaft 96.

In the link mechanism, a drive shaft 95 and a connecting shaft 96 are connected through a ball joint 97, and a connecting shaft 96 and a link rod 93 are connected through a clevis joint 98, and the driving force from the actuator 18 is can be smoothly transmitted to the link arm 94. In addition, in order to define the fully open position of the movable vane 87 by regulating the stroke of the drive shaft 95, a bracket (9) is provided integrally with the turbine casing 80.
A stopper 101-, which comes into contact with an adjustment pole I-100 screwed on, is fixed to the connecting shaft 96.

The actuator 18 has a cylindrical casing '102 with a bottom.
and a cover 103 caulked to this opening end, and a tire flam 104 is sandwiched between the diaphragm]
04 defines a negative pressure chamber 105 and a positive pressure chamber ]06 therein.

At the center of the tire flam 104, there is a retainer 1-07.
The other end of the drive shaft 95 is fixed via 1-08.

Then, the retainer 1°7 and the casing 1 on the negative pressure chamber 105 side
A compression coil spring 109 is sandwiched between the spring 109 and the bottom wall of the diaphragm 104 and the drive shaft 95.
It is strong.

The drive shaft 95 is slidably supported at the center of the bottom wall of the casing 102 . The protruding portion of the drive shaft 95 from the bottom wall of the casing 102 is made of a flexible and friction-free material that is formed by cutting a cylindrical portion made of fluororesin into an annular shape from the inside and outside. It is sealed with bellows 11-0. In addition, negative pressure chamber 1
．． 05 and the inside of the bellows 110 communicate with each other via a through hole 111.

A negative pressure inlet port 2 is formed in the casing 102 for communicating the negative pressure chamber 1-05 with the outside. Further, the cover 103 is formed with a positive pressure inlet 113 for communicating the positive pressure chamber 106 with the outside.

In this actuator]-8, the positive pressure inlet 1-
When positive pressure is introduced from 13 toward the positive pressure chamber 106, the tire flam 1.04 is pressed to the left in FIG. 3 against the biasing force of the compression coil spring 109. 95 is driven leftward. Also, negative pressure inlet]
When negative pressure is introduced into the negative pressure chamber 1-05 from the negative pressure chamber 1-05, the drive shaft 95 is similarly driven to the left via the tire flamm r-04. That is, in a low opening range of the throttle valve where the intake negative pressure P3 is high, the actuator 18 operates in a direction that pushes out the drive shaft 95. As a result, the link rod 93 is displaced to the left in FIG. The movable vane 87 is driven inwardly about the pivot 88 via the moon 89 . By opening the movable vane 87 in this manner, a so-called large-capacity state is created in which the nozzle gap GN defined by the lap between the front edge of the fixed vane 84 and the rear edge of the movable vane 87 is maximized. (The state shown by the imaginary line in Figure 3).

When the negative pressure control solenoid valve 35 described above is controlled to cut off the intake negative pressure P to the negative pressure chamber 105, the negative pressure in the negative pressure chamber 105 decreases and the coil spring 109 (= The drive shaft 95 is pulled in by the i force.Then, the link rod 93
The link arm 94 is displaced to the right in the figure, and the link arm 94 is
The seesaw part 91 is rotated counterclockwise around the center, and the movable vane 87 is driven outward around the pivot shaft 88 via the lever part 89 that engages with the slits 90 at both ends (Fig. 3). state shown by the solid line). By closing the movable vane 87 in this way, a so-called small capacity state is formed in which the nozzle gap GN defined by the lap between the front edge of the fixed vane 84 and the rear edge of the movable vane 87 is minimized. Ru. Therefore, the exhaust gas flow is maximally throttled and accelerated,
Since the swirling flow forms in the inner circumferential passage 86 and drives the turbine wheel 83, the supercharging effect in the low engine speed range is ensured.

When the engine speed increases and the supercharging effect becomes sufficient,
The positive pressure control solenoid valve 34 is controlled to introduce supercharging pressure P2 into the positive pressure chamber 106. As a result, actuator 1-8
operates in the direction of pushing out the drive shaft 95, and the link arm 9
4 tilts in the opposite direction to that in -1- to rotate the seesaw member 91 clockwise, and the lever 89 tilts the movable vane 81- inward. By widening the nozzle gap GN in this way, the speed of the exhaust flow is not increased and the flow path resistance is reduced, making it possible to reduce the exhaust back pressure against the engine.

In this embodiment, the opening of the movable vane 81 is mainly controlled by the positive pressure control solenoid valve 34, but in some cases, the negative pressure control solenoid valve 35 may also be used. good.

(Left below) Next, a control program incorporated into the electronic control circuit 21 to control the valve timing switching solenoid valve 1.6 will be described with reference to FIG. 4a.

In a first step 201, it is determined whether the engine is in the starting mode, that is, whether the engine is cranking.

If cranking is in progress, the elapsed time TDST (for example, 5 seconds) after engine start is determined in the second step 202.
After setting, prepare to start the timing operation. Next, in a third step 203, a valve closing command is issued to the solenoid valve 16, and low speed valve timing operation is selected. Then, in a fourth step 204, the elapsed time TDIIVT (for example, 0.1 seconds) after the switching operation to high-speed valve timing operation is set, and preparations are made for a delay time measurement operation after the switching operation. Next, in the fifth step 205, the maps T1□ and .theta.16□, which correspond to the low-speed valve timing operation, are selected as the basic fuel injection amount map and ignition timing map used in the fuel injection control routine, and the sixth step Rev limiter value N for fuel power cut at 206! IFC is set to a value N10. corresponding to low speed valve timing operation. . 1. Set to .

By the way, the fuel injection amount T. UT is the basic fuel injection amount T
1, the correction coefficient is 1, and the constant term is 2, it is given by the following equation.

T OUT -K 1T l+ K In addition, in 1, the intake air temperature correction coefficient KTA and water temperature correction coefficient KTw, which increase the amount of fuel when the intake air temperature TA and the cooling water temperature Tw are low, the engine speed NF, the intake negative pressure PB, Throttle opening θT1
1, the high load increase coefficient KwOT increases the amount of fuel in a predetermined high load area defined by
0 RPM) includes a feedback correction coefficient KO2 that corrects the deviation of the air-fuel ratio from the stoichiometric air-fuel ratio in the 0□ feedback region, and 2 also includes an acceleration increase constant that increases the amount of fuel during acceleration. .

The basic fuel injection amount T1 is the engine rotation speed NF.

is set based on experimental values so that the intake air-fuel mixture has a target air-fuel ratio close to the stoichiometric air-fuel ratio according to the amount of air intake into the cylinder in each operating state specified by and intake negative pressure PB. Two sets of T1 maps, a T1L map for low-speed valve timing operation and a T1,1 map for high-speed valve timing operation, are used in the electronic control circuit 21.
Let me remember it.

Further, as the valve opening period becomes shorter, the valve acceleration during the valve opening operation increases, and the load acting on the timing belt increases. At the same time, due to the increase in valve acceleration, the engine rotational speed NE, which causes valve jump, decreases. Therefore, the allowable rotational speed is also different between low-speed valve timing and high-speed valve timing, which have different valve opening periods, and in this embodiment, the rev limiter value during low-speed valve timing operation is N11°.

, to a relatively low value (for example, 7500 RPM), and the rev limiter value NHFCl during high-speed valve timing operation.
+ is set to a relatively high value (for example, 8100 RPM).

On the other hand, if cranking is not in progress in the first step 201,
That is, if it is determined that the engine is already in operation, in a seventh step 207 it is determined whether signals from various sensors are normally input to the electronic control circuit 21.
In other words, it is determined whether failsafe should be used. If it is determined that the system is not in fail-safe mode, that is, that it is in a normal state, in the eighth step 208, the remaining time of the elapsed time after startup (T)81 set in the second step 2.2 is determined. . If the remaining time is not 0, proceed to the third step 203; if the remaining time is 0, proceed to the ninth step 209.
The cooling water temperature Tw is the set temperature Tw1 (for example, 60°C)
It is determined whether or not the temperature is lower than that, that is, whether or not warming has been completed. If it is determined that Tw is Tw, the process proceeds to the third step 203, and if Ty≧Tw, the process proceeds to the tenth step 210, where the vehicle speed V is set to an extremely low set vehicle speed V+ (including hysteresis, for example). 8 to 5 km/h) or less. Here, if V<V, the process proceeds to the third step 203, and if ■≧■1, it is determined in the first step 211 whether or not the vehicle is a manual transmission vehicle MT.

To summarize the operation so far, before starting, during cranking, immediately after starting, before warm-up is completed, and when stopped or slowing down, low-speed valve timing operation is unconditionally set.
At the same time, fuel injection control corresponding to this is set.

In other words, this is a measure to prevent malfunction of the connection switching device 51 or occurrence of irregular combustion due to the viscosity of the lubricating oil when the engine is cold.

If it is determined in step 2]1 that the vehicle is not a manual transmission vehicle, that is, it is an automatic transmission vehicle AT, then in step 212 it is determined whether the shift position is in the parking P or neutral N range. Discriminate, P-N
If the map is in the range, it is determined in a thirteenth step 213 whether or not the T1.1 map for high-speed valve timing operation was selected last time, and if it has not been selected, the process proceeds to a third step 203. On the other hand, in the case of a manual transmission vehicle MT, in step 1-4 21-4, the lower limit rotational speed NF, □7 (hysteresis (for example, 4,800 to 4,600 RPM) and the current engine rotational speed N5.

If it is determined that NE is NEI, it is determined in the 15th step 21.5 whether or not the T1,1 map for high-speed valve timing operation was selected last time, similarly to the 13th step 213. However, if it has not been selected, the process advances to the third step 203.

According to the flow up to this point, even if the engine speed N8 is high, it is in a stopped state, or even if it is in a running state, it is rotating slowly or at a low speed, and if it is not yet running at high speed, the low-speed valve timing is determined. You can see that it is set to driving.

On the other hand, in the fourteenth step 214, N, ≧N, :1. If it is determined that T11, MAP and T1□1 are determined in accordance with the subroutine shown in FIG.
Search for map, current engine speed NF,
The T17 value and the T1.1 value corresponding to the intake negative pressure PB are determined, and then in the 17th step 21.7, in accordance with the subroutine shown in FIG. 4C, the values determined experimentally in advance based on the fuel injection amount The TVT value corresponding to the current NE is calculated from the table of high load determination values TV1.

Here T1. - The value of TH is determined by determining whether or not a valve opening command was issued for the solenoid valve 16 last time, and when a valve opening command has not been issued, that is, when high-speed valve timing operation has not been performed so far. In this case, T1. used in the sixteenth step 216 is used. - Set the value to 11□, the value searched from the map, and if a valve opening command is issued, perform processing to set the value to the value obtained by subtracting T1 from the search value to a predetermined hysteresis amount, Also, the TV in the 17th step 21.7
Similarly, in the process of calculating the r value, it is determined whether or not a command to open the solenoid valve 16 was issued last time, and if the command to open the solenoid valve 16 has not been issued, the
The T value is the value calculated from the TVT table, and when a valve opening command is issued, the TV engineering value is processed to be the value obtained by subtracting a predetermined hysteresis amount ΔTvT from the calculated value, thereby adjusting the valve timing. Hysteresis is added to the switching characteristics of the fuel injection amount at the switching point.

Next, in the 18th step 218, this TvT value and the previous fuel injection amount T are determined. Compare with UT. Here on Tv
If it is determined as T, in the nineteenth step 219,
The output in high-speed valve timing operation always exceeds the output in low-speed valve timing operation.'' Upper limit engine rotation speed NEU (including hysteresis, e.g. 5900 to 570O)
RPM) and the current engine rotational speed N8. If it is determined that NE<NEU, the TI obtained in the 16th step 216 is determined in the 20th step 220.
Compare the L value and the T111 value, T , L > T , □1
If it is determined that this is the case, a valve closing command is issued to the electromagnetic valve 16 in a twenty-first step 221, that is, a low speed valve timing operation is selected.

On the other hand, if it is determined at the 13th step 213 or the 15th step 215 that the T... map was selected last time, that is, when the vehicle is in a low-load, low-speed state after high-speed driving, the 21st step is performed. Proceed to 221.

On the other hand, if it is determined in the 18th step 218 that Tout≧TvT, the determination is N in the 19th step 219. ≧NE
If it is determined as U, T10 is determined in the 20th step 220.
．． ≦T1. If it is determined as □, a valve opening command is issued to the solenoid valve 16 at the 22nd step 222, that is, high-speed valve timing operation is selected. From the flow up to this point, it can be seen that the valve timing switching point is determined based on the engine rotational speed NE and the required fuel injection amount.

Now, in the high-load operating range, the air-fuel mixture is corrected so that it tends to be rich, and in the high-load operating range, it is more advantageous to select high-speed valve timing operation to increase the output. However, if the switching point of the valve timing is determined uniquely, it tends to cause hunting at the boundary portion or cause a shock due to torque fluctuation at the time of switching. Therefore, in this embodiment, during driving, the 18th to 20th combined steps 218 to 220
By going through these steps, optimal switching control can be performed.

After selecting the high speed valve timing operation, in the 23rd step, a flag FLVT=0 indicating that the low speed valve timing operation has not been selected is confirmed in the turbocharger control routine to be described later. If it is confirmed here that the turbocharger side is in a state that requires low-speed valve timing operation, the third step 20 is performed.
If not, proceed to the twenty-fourth step 224.
The signal from the oil pressure switch 22 for confirming the operating status of the switching control valve 17 is determined. Here, the oil pressure switch 22
is off, that is, when it is determined that hydraulic pressure is acting on the connection switching device 51, the delay time T after the connection switching device is activated, which is set in the fourth step 204.
The remaining DHVT time is determined in a twenty-fifth step 225. If it is determined that TDIIV□-〇 here, the second
In step 226, an elapsed time TDLVT (for example, 0.2 seconds) after switching to low-speed valve timing operation is set, and preparations are made for a delay time measurement operation after switching.

Next, in the 27th step 227, the fuel injection amount T1□1 map and ignition timing θ160. corresponding to high-speed valve timing operation are determined. is selected, and in the 28th step 228, the rev limiter value NllPo is set to NI for high-speed valve timing operation.
Set to IFCI□.

On the other hand, after a valve closing command is issued to the solenoid valve 16 in the 21st step 221, the oil pressure switch signal O1 is determined in the 29th step 229. If it is determined that the oil pressure switch 22 is on, that is, that the oil pressure is not acting on the connection switching device 51, the remaining time of TD and -v□ set in the 26th step 226 is read, and the remaining time of TD and -v ,
If v□-0, the process advances to the fourth step 204.

Even though the low-speed valve timing operation has been switched to the high-speed valve timing operation in this way, if the oil pressure switch signal OP is not turned off at the 24th step 224, the process advances to a 30th step 230, where the oil pressure switch signal O1 Although the operating condition was maintained at low speed valve timing until the valve was turned off, and conversely, even though the high speed valve timing operation was switched to the low speed valve timing operation, at the 29th step 229, the oil pressure switch signal o1° was changed. If it does not turn on, proceed to the twenty-fifth step 225,
Oil pressure switch signal 0. Maintain operating conditions at fast valve timing until the valve is turned off.

Also, the setting time T of the dual switching delay timer set in the fourth and 26th steps 204 and 226 described above,
, ヮヮ・TL HV T is until the solenoid valve 16 is activated, the spool valve 7o of the switching control valve 17 is moved, the oil pressure in the oil supply passage 57 is changed, and the switching operation of the switching pins of all cylinders is completed. is set based on response time. and oil pressure switch signal 0. Even if the start of switching operation is confirmed from , when switching from high speed to low speed, T +u, Vr =
0, T when switching from low speed to high speed, □+, vr'=
Until the value becomes 0, it is assumed that the valve timings of all cylinders have not been changed yet, and the operation is maintained under the fuel injection amount control before the valve timing change command.

Note that the 13th step 213 and the 1-5th step 215
If the T map has not been selected previously, that is, immediately after starting driving or during acceleration, low-speed valve timing operation is set without checking the oil pressure switch signal O4. This is a measure taken in consideration of the adverse effects when the signal remains off due to a defect in the oil pressure switch 22 or the like. Furthermore, when the turbocharger side requests low-speed valve timing operation in the 23rd step 223, the fuel injection control is also immediately switched to support low-speed valve timing operation, but this is not the case in the case of supercharging, etc. This is a measure to prevent abnormal combustion.

Next, the i'1rlJ control program for the solenoid valve 34 for changing the supercharging capacity, ie, supercharging pressure, of the turbo charger 7 will be explained with reference to FIGS. 5a and 5b. However, the solenoid valve 34 for positive pressure control used in this system
is a duty control solenoid valve. In addition, this boost pressure control includes oven loop control that controls boost pressure based on the basic boost pressure control amount (hereinafter referred to as basic tutee DM), and an oven loop control that controls the boost pressure based on the basic boost pressure control amount (hereinafter referred to as basic chutie DM), This is a control system that also has feedback control that performs supercharging pressure control by correcting the basic duty DM according to the deviation from the supply pressure.

In the first step 301, it is determined whether the engine is in the starting mode or not, that is, whether the engine is cranking or not. If the engine is in the starting mode, the low speed valve timing operating condition is fixed in the second step 302. flag F
+, v・r = 1. Then the third step 30
Timer TD1.1.3 for delaying the start of feedback control. After resetting, the fourth step 304
Duty D for the solenoid valve 34. UT is set to 0, and duty D is set in the fifth step 305. Output U7. However, duty D in this main routine. As the value of ll and I increases, solenoid valve 3
4, the duty ratio of the solenoid becomes smaller, but the duty ratio] -00
%, that is, the state in which the movable vane 87 is driven inward to the maximum extent, that is, the state in which the solenoid valve 34 is fully opened and the air gap circulation area between the fixed vane 84 and the movable vane 87 is maximized, and DOIJT = 100 corresponds to a duty ratio of 0%, that is, a state in which the movable vane 87 is driven outward to the maximum extent, that is, a state in which the air gap circulation area is minimized.

By the way, the feedback delay timer TI)FB in the third step 303 is selected according to the subroutine shown in FIG. Here, depending on the rate of change ΔP2 of supercharging pressure P2, three timers TDFIII, T1, 1・B2, TI
) FB3 is selected, but the boost pressure change rate Δ
P2 is the current supercharging pressure P2N and the six previous supercharging pressure P2
It is determined by the difference from N-6 (8P2=P2N P2N-6). That is, the main routine shown in FIGS. 5a and 5b is updated by the TDC signal, but since the boost pressure change rate ΔP2 is too small with only one TDC signal, the boost pressure behavior, that is, the boost pressure change rate In order to read ΔP2 accurately,
The difference between the supercharging pressure P2N6 and the six previous supercharging pressures is determined. In addition, the setting high change rate eight P2P1. ．． and the set high rate of change ΔP2121° is the engine rotation speed N. It is a predetermined numerical value according to P2≦8P21'1.
．． In the case of T1. .

Old is set, 8P21'1. ．． <∆P2≦to 8P2・
In case of IIO, TI)FB2 is set and ΔP21'l
TDFB3 is set when ΔP2 is less than □. Moreover, when the relationship TDFBo<TDFn2<TDFB3 holds and the boost pressure change rate ΔP2 is small, that is, when the boost pressure P2 is changing slowly, the delay time TDFB is set small, and the boost pressure change rate ΔP2 increases. When the boost pressure is large, that is, when the boost pressure is changing rapidly, the delay times TD and B are set large. In this way, when transitioning from open-loop control to feedback control, an optimal delay time TDFB with no excess or deficiency can be set according to the speed and speed of load changes, and hunting phenomenon can be prevented from occurring during the transition. becomes possible.

If it is determined in the first step 301 that the engine is not in the starting mode, it is determined in the sixth step 306 whether or not fail-safe mode is to be performed. This is done by checking the ECU-CPU self-diagnosis and the manual signals from each sensor including the oil pressure switch signal O1 to indicate the operating state of the valve timing connection switching device 51, and if there is an abnormality, the second step 302 is performed. If normal, proceed to step 7 307
Proceed to. In the seventh step 307, the intake temperature TA and the set high intake temperature TA□4 are compared, and if TA is less than TAL, the second
Proceed to step 302, and if TA≧TA4, the eighth step
Proceed to step 308. In the eighth step 308, the cooling water temperature Tw is compared with the set high cooling water temperature Tw,
If wl, the process proceeds to the second step 302, and if Tw≧TwL, the process proceeds to the ninth step 309. In the ninth step 309, the intake air temperature TA and the set high intake air temperature T are
AH, and if T, > TA, □, proceed to the second step 302, and if TA≦TA11, proceed to the 10th step 302.
Proceed to step 310. In the tenth step 310, the cooling water temperature Tw and the set high cooling water temperature TwIl are compared, and TW>
In the case of Tw, , proceed to the second step 302, and Tw≦
In the case of TWI□, the 11th. Proceed to step 311. At the eleventh step 311, the shift position of the automatic transmission is determined, and if the shift position is in the parking P or neutral N range, the process proceeds to the second step 302, otherwise the process proceeds to the twelfth step 312.

To summarize the flow up to this point, if the vehicle is in running condition, some abnormality is recognized in the control system, and the intake air temperature TA and cooling water temperature Tw are out of the predetermined range, the other factors Regardless of this, control is performed so that the cross-sectional area of the flow path between the fixed vane 84 and the movable vane 87 in the turbocharger 7 is maximized. This is because it can be concluded that the conditions for stable operation of the engine are not satisfied in any of the above steps, so it is rather undesirable to introduce supercharging pressure P2 into the combustion chamber in such a state. This is because it clearly promotes stability.

At the same time, the flag F1. When V = 1, it indicates that the operating condition is fixed to the low speed valve timing, and the connection switching device 51 is set to the low speed valve timing.

If it has been determined in the steps up to this point that the engine is in stable operating condition and is in running condition,
At a twelfth step 312, it is determined whether the shift position is the first speed. If it is determined that the valve is not in the 1st speed position, a flag indicating that the fixation of the low speed valve timing operating condition is to be released is set to FLVT=0 in the 13th step 313. Proceed to step 314. If it is determined that the position is in the first speed position, the basic duty DM as the basic boost pressure control amount is subtracted in the 15th step 31.5, and at the same time, in the 16th step 316, the low speed valve Set the flag to F to indicate that the timing operation conditions are fixed.
After setting LVT=1, the process proceeds to the fourteenth step 314.

By the way, the basic duty DM can be searched from the map described later.''In the 15th step 315 of the second paragraph, this is done according to the subroutine shown in FIG. A value is subtracted. That is, a discrimination zone that requires a reduction in the DM value is set in advance in accordance with the operating conditions determined by the engine rotational speed NE and the intake negative pressure P, and whether the discrimination zone is within this discrimination zone or outside the discrimination zone. It is determined whether or not to subtract the DM value depending on whether the DM value is subtracted or not. Here, the engine output torque can be determined from the engine speed N8 and the intake negative pressure PB, but the boundary line of the discrimination zone indicates the allowable torque of the gear shaft in the first gear position, and the processing here teeth,
This is to prevent the force acting on the gear shaft in the first speed position from becoming overloaded. Here, if it is outside the discrimination zone, that is, if it does not exceed the allowable torque, the searched DM value is left as is and the process proceeds to the next step.
If it is within the discrimination zone, that is, if it is in a region exceeding the allowable torque, a flag indicating that the feedback control state is in effect is set to FOP. = 0 or not, and when in the open loop control state, subtraction is performed such as DM-Search DM-DF, and the duty D for the solenoid valve 34 is determined.

When u'r has a tendency to decrease somewhat and is in a feedback control state, the following subtraction is performed: P2R - search P2R - ΔP2R, and the target supercharging pressure P2R is set somewhat lower. However, Dl is a preset subtraction value, P2
□ and □ are target boost pressures set according to the engine rotational speed NE and intake air temperature TA used in the feedback control state, and 8P21+ is a preset subtraction value.

Through the processing up to this point, the valve timing is set to correspond to low speeds, and the boost pressure is also set to a low value in order to prevent overtorque due to sudden start in the first speed position.

Next, in a fourteenth step 31-4, it is determined whether the connection switching device 51 is in a high-speed valve timing operation state. If it is determined that the high-speed valve timing is in operation, the process proceeds to the 17th step 317, and if not, the process proceeds to the 18th step 3]8. Then, as the high boost pressure judgment guard value P2+1G, the table P2+1011 corresponding to high-speed valve timing operation is the first one.
-7 is selected at step 317, and table P2110+ corresponding to low speed valve timing is selected at 18th step 3]8. However, the high boost pressure determination guard value P2+1G is a value that is preset corresponding to the engine rotational speed N9, and is set so as to obtain the maximum output while taking engine durability into consideration.

In addition, to determine whether the current valve timing state is compatible with low speed or high speed, it is detected in the control unit whether or not an excitation signal is currently being emitted to the solenoid valve 6. This is done by

Next, in a fourteenth step 319, the high supercharging pressure determination guard value P2+1G obtained from the table selected corresponding to the valve timing state at this time is compared with the current supercharging pressure P2. Here, if it is determined that P2>P2+1G, that is, supercharging, the second step 3
02, requests the valve timing switching control program to set the valve timing to a low speed valve timing, and controls the supercharging pressure P2 in the direction of lowering it.
If it is determined that this is the case, the process proceeds to the 20th step 320, and it is again determined whether or not the high-speed valve timing operation is in progress.

If it is determined in the 20th step 320 that the valve is in a high-speed valve timing operation state, the 21st step 320
At step 21, the basic duty DMI+ is retrieved from the map corresponding to the high-speed valve timing operating state, and at step 22, this value is determined as the DM value. If it is determined no, at the 23rd step 323, the basic duty DM+ is searched from the map corresponding to the low speed valve timing operating state, and at the 24th step 324, this value is determined as the value. . By the way, this basic duty DM is set in advance according to the engine rotational speed N and the throttle opening θTl+, and the basic duty DM that matches the current load situation is searched from the setting table.

In this way, the engine rotational speed N6 and the throttle opening degree θ. A map determined by It is possible to respond accurately to each operating state. still,
The throttle opening θTH is used as a representative parameter indicating the engine load condition, but this is based on the intake negative pressure P.
8 or the fuel injection amount.

Next, in the 25th step 325, the duty correction coefficient KMoD, the duty atmospheric pressure correction coefficient KPAD (
0.8 to 1.0), and duty intake temperature correction coefficient K
Search for each TAD (0,8 to 1.3). However, the duty correction coefficient KMOD is searched from a map determined by the engine speed NE and the intake air temperature TA, and is learned when the optimum boost pressure P2 (described later) falls within a predetermined deviation. Updated from time to time. Further, the duty atmospheric pressure correction coefficient K PAD is determined in accordance with the intake pressure PA, and the duty intake temperature correction coefficient KTAI is determined in accordance with the intake air temperature TA.

These controls allow the system to adapt to external factors at any time.

Next, in a twenty-sixth step 326, a correction coefficient KDN is searched according to the subroutine shown in FIG.

This subroutine interrupts the main routine of FIGS. 5a and 5b every time the TDC signal is sent, and the duty is D. When IT is 0, reset timer TDN and set duty D. The correction coefficient KDN is set to the initial value KDNO(
For example, set it to 0.5).

Then, after the timer TDN has passed a certain set time TDND (for example, 5 seconds), a predetermined addition value ΔKDN (for example, 0.01) is added for each TDC signal to obtain a new correction coefficient KDN. The correction coefficient KDN is 1
．． After it exceeds 0, it is set to 1.0.

The correction coefficient KDN determined in this way is used in the correction formula for the duty DoU□, which will be described later. Duty D in a specific operating range where the temperature is abnormally high or low, or where the supercharging pressure P2 is abnormally high. Force UT to 0,
That is, this is for stably controlling the duty DoUT when the state in which the gap between the fixed vane 84 and the movable vane 87 is maximized is released. In other words, if the duty D OUT immediately returns to the normal value when returning to the normal operating state from the specified operating state of DoU□-0, the boundary between the specific operating range and the normal operating range will become irregular. Control may occur. Therefore, after, for example, 5 seconds have elapsed after returning to the normal operating range, for example, 0.
Duty D by increasing correction coefficient KDN by 1. U.T.
The occurrence of such irregular control is avoided by gradually returning the control value to the normal control value.

Next, in the 27th step 327, the current throttle opening θ□1 and the preset reference throttle opening θTHFB are determined.
Compare with. This set throttle opening θTHFB is
It corresponds to medium and high load operation areas, and is set to determine whether to shift from open loop control to feedback control. By employing the throttle opening degree θ7□□ as the determination parameter in this manner, it is possible to accurately determine whether or not the driving situation at that time requires supercharging. Here, θ, 1□≦θT
If it is determined that the condition is IIFB, that is, if open loop control is to be continued, the feedback delay timer TDFB shown in FIG. 6 (third step) is reset in the twenty-eighth step 328, and then the 29 steps 329
Proceed to. Also, in the 27th step 327, θ1. ．． 〉θ
If it is determined to be THFB, the 30th step 330
It is determined whether or not the connection switching device 51 is in the low speed valve timing operation state, and if it is determined that the low speed valve timing operation is being performed, it is determined that open loop control should be continued and the process proceeds to step 28 328. . This is because low-speed valve timing operation is often in a transient state and the absolute value of torque is relatively low, so this is a measure to fix it to open-loop control and rather improve followability.

At the 29th step 329, the set subtraction duty D7 and the set addition duty DTRB are searched. The set subtraction duty D1 corresponds to the rate of change ΔP2 of the supercharging pressure P2, and is determined according to the subroutine shown in FIG. Here, in the case of θ, 11>θTHFH, that is, in the medium/high load operation region where open loop control shifts to feedback control, the boost pressure change rate ΔP2 and the engine rotation speed N.

A preset subtraction duty DT is selected based on the relationship between .theta.Tl+ and .theta. and when .theta.Tl+.ltoreq..theta. HI'B, DT=0, and the basic duty DM is not corrected.

By the way, the set subtraction duty D'r is set to increase stepwise in accordance with an increase in the boost pressure change rate ΔP2, and the engine rotation speed N. Depending on the range of This results in
The larger the boost pressure change rate ΔP2 and the larger the engine rotational speed NF, the larger the subtraction value is set. This process is started before the actual supercharging pressure P2 reaches the target supercharging pressure P2R, so that the transition from oven loop control to feedback control can be made smoothly.

Further, the set addition duty DTRB is determined according to the subroutine shown in FIG. Here, when the oven loop control state (Fo+.-1) is in effect and the boost pressure change rate ΔP2 is in a negative state, the set addition duty D determined by -8P2 and the engine rotation speed Nl is , 1□, and B are selected, and the set subtraction duty D□ is also set to 0.

In addition, if the feedback control state (Fopc-0) or the boost pressure change rate ΔP2 is positive,
The set addition duty D i' R11 is set to zero. This setting addition duty D154,1. Similarly to the above-mentioned set subtraction duty D'r, the holding is changed according to the engine rotational speed N6 and the negative charge pressure change rate -ΔP2, and the larger the engine rotational speed N, the more negative the The larger the supercharging pressure change rate -ΔP2 is, the larger the additional value becomes. As a result, the reaction of the setting subtraction duty D is also corrected, and stable supercharging pressure can be controlled.

In this way, each correction coefficient KMo1)·KpA□.

After determining the set subtraction duty DT and the set addition duty DTR8, the third
Duty D at step 331. ll□ is corrected by the following formula.

(-line margin) 1) ou'r -KMOD XK, AD xKTA
DXK,.

X (DM+DTR, -D□) Therefore, the output duty D output from the fifth step 305. u'r is set by comprehensively taking into account the operating conditions of the engine, taking into account the above contents and external factors, and automatically performs optimal boost pressure control corresponding to the load situation at that time. I can do it.

Next, in a 32nd step 332, a flag is set to F to indicate that the current state is oven loop control. 1. .

-1, and the process proceeds to the 33rd step 332. Duty D here. It is checked whether u'r exceeds a limit value set in advance according to the engine rotational speed NF, and if it is within the limit value, the duty D is set in a fifth step 305. u'r is output.

On the other hand, if it is determined at the 30th step 330 that the low speed valve timing operation is not in progress, the process proceeds to a 34th step 334 (FIG. 5b).

In the 34th step 334, the previous flag is determined and
"or'.-1-1, that is, if it is determined that oven loop control was performed last time, in the 35th step 335,
The current supercharging pressure P2 is compared with the duty control start determination supercharging pressure P2ST in the oven loop control state. This duty control start determination supercharging pressure P2ST is obtained from P2S'l'=P2R-ΔP2S'r. However, △P2ST is a subtraction value that is preset based on the boost pressure change rate △P2 and the engine rotation speed N9, and as the engine rotation speed increases and the boost pressure change rate ΔP2 increases, It is set to be large.

When it is determined in the 35th step 335 that P2>P28.1, the supercharging pressure P2 is compared with the feedback control start determination supercharging pressure P21.8 in the 36th step 336. This feedback control start determination supercharging pressure P2++I
1 is obtained by P 2Fll -P 2□, -ΔP2+'R. However, 8P2FR is "2 ΔP
Similar to 2ST, this is a subtraction value that is preset according to the boost pressure change rate ΔP2 and the engine rotation speed NE.

Here, if it is determined that P2>P2FB, the 37th
At step 337, the feedback delay timer TD is
It is determined whether the FB has elapsed or not, and if it has elapsed, the process advances to the thirty-eighth step 338.

Also, in the 34th step 334, the flag is set to FOPC=
0, that is, if it is determined that the previous feedback control was performed, the process proceeds to step 38, and if it is determined that P2≦P2ST in step 35, the process proceeds to step 39.
Go to step 339, and at the 36th step 336, P2≦P
If it is determined that 2F[ ], the 28th step 328
Then, in the 37th step 337, the feedback delay is
If the timer TDFII has not elapsed, the process proceeds to the 29th step 329, respectively.

At the 39th step 339, the set duty DS as the auxiliary basic boost pressure control amount, which is preset according to the engine speed N8, is searched, and then at the 40th step 340.
Duty D according to the following formula. LIT is calculated.

DOUT-DSxKTADxKPAD Next, in the 41st step 341, the feedback delay timers TD and B are reset, and then the process proceeds to the 33rd step 333.

The process leading to the fortieth step 340 described above is based on the supercharging pressure P
2 is intended to obtain stable boost pressure control in the operating range until target boost pressure P2R is reached, and is based on duty D8, which is preset according to engine rotational speed N. By determining the output duty D OUT based on the above, it is possible to suitably prevent overshoot from occurring regardless of the boost pressure change rate ΔP2.

On the other hand, at the 38th step 338, the supercharging pressure change rate ΔP2
The absolute value of is compared with the feedback control determination supercharging differential pressure G6,2. This G4,2 is set to, for example, 30+nmHg, and if 1ΔP,, l>GaF2, the process proceeds to the 29th step 329, and 1ΔP2 l≦G 6F
In the case of 2, the process proceeds to the 42nd step 342. In other words, 1
ΔP2 l > GaF2 , that is, boost pressure change rate ΔP2
If the feedback control is started in a state where the curve is steep beyond the limit, it will cause hunting, so the process returns to the 29th step 329 and open loop control is performed.

In the next 42nd step 342, it is determined whether the connection switching device 51 is in a high-speed valve timing operation state.

If it is determined that the high-speed valve timing is in the operating state, the engine rotation speed N is determined in a 43rd step 343.

and the target supercharging pressure P2R1□ for high-speed valve timing operation, which is set in advance based on the intake temperature TA, and
In step 344, this P2R11 is set to the target supercharging pressure P2.
Let's call it R. If it is determined that the high-speed valve timing operation is not in operation, the target supercharging pressure P2RL for low-speed valve timing operation is searched for in the 45th step 345, and this P21N is set as the target supercharging pressure in the 46th step 346. Let the pressure be P2R. This is because the intake air filling efficiency changes depending on the valve timing, that is, the valve opening, so by changing the target boost pressure P2R setting in response to switching the valve timing, the engine output can be increased more efficiently. This is a measure for the purpose of

Next, in a 47th step 347, it is determined whether the shift position of the automatic transmission is at the first speed position. If it is determined that the vehicle is in the first gear position, then in step 348, if the operating state is in a predetermined determination zone according to the subroutine shown in FIG. After performing the following subtraction, the process proceeds to the 49th step 349.

However, this ΔP2R is a subtraction value that is set when the shift position is at the first speed position. Also the 46th
If it is determined in step that the shift position is at a position other than the first speed position, the process proceeds to step 349 without subtracting the target supercharging pressure P2□.

At the 49th step 349, the atmospheric pressure correction coefficient K 11 A P 2 for boost pressure set in advance according to the atmospheric pressure PA is searched, and at the 50th step 350, the following calculation is performed to determine the target boost pressure P2H. Make corrections.

Correction P2R-Search P2RxK, Ap2×KR1B where KR□8 is a correction coefficient set corresponding to the engine knock state.

At the 51st step 351, it is determined whether the absolute value of the deviation between the target boost pressure P2R and the current boost pressure P2 is greater than or equal to a predetermined set value GP2. However, this GP2 is the dead zone defining pressure during feedback control, for example, 20 mmHg.
It is set to a certain degree. Here, in the case of P2RP21≧GP2, the process proceeds to the 52nd step 352, and the proportional control term DP of the duty is calculated using the following equation.

Dp -Kp In this FIG. 11, the engine rotational speed NE is the first switching rotational speed N, +11. If the following is true, select 11 as the feedback coefficient related to the integral control term to be described later together with K and 1, and select 11 as the feedback coefficient related to the integral control term to be described later.
When E exceeds the first switching rotational speed NFB□ and is less than or equal to the second switching rotational speed Nl, B2, K, 2・K1□ is selected, and furthermore, the engine rotational speed N67, the second switching rotational speed N1, rI2 When it exceeds, select KP3/K13.

Then, in the 53rd step 353, the engine rotation speed N5
and correction coefficient KMo! according to intake air temperature TA! .

is searched, and at the 54th step 354, the previous flag is F. , c-1, that is, whether this is the first feedback control state. F here.

PC-1, that is, in the case of open loop control last time, in the 55th step 355, the previous integral control term DI(
N-1) is calculated according to the following formula.

D + (N-+) = KTΔ,, ×KPAD xDMX
(KMo, -1) After completing this calculation, the process proceeds to the 56th step 356, but in the 54th step 354, Fop
If c=0, that is, if it is determined that oven loop control is not being performed, the process bypasses the 55th step 355 and proceeds to the 56th step 356, where the current integral control term opening is calculated according to the following equation.

DIN=DI(N-11++(P2RP2)
After that, in the 57th step 357, the duty Do1.
is calculated. That is, I) ou'r=to, -A,,XK,, 7. DXKD
The calculation NXDM+Dp+DIN is performed, and at the 58th step 358, the flag is set to F'o+'. After setting = 0, the 33rd step 333
Proceed to.

On the other hand, if it is determined at the 51st step 351 that IP2+<G, 2, then at the 59th step 359 the proportional control term is set to -0 and the integral control term DIN-D+(, -4). Next, in the 60th step 360, it is determined whether the atmospheric pressure PA exceeds the set atmospheric pressure PAM (for example, 650 mmHg), and in the 61st step 361, it is determined whether the water temperature Tw is within a certain range. Then, the 62nd step 3
In step 62, it is determined whether or not the retard amount T2R is 0, that is, whether or not the knocking state is removed.
It is determined whether the shift position is other than the 1st gear position, and if all of these conditions are met, the 64th gear position is determined.
The process proceeds to step 364, and if even one of these conditions is not met, the process proceeds to step 357.

At the 64th step 364, the duty correction coefficient KMO is
The coefficient KR for learning I) is calculated according to the following equation.

K++ -(KTAD XDM 4-DIN)/(K
TAD

In order to search and learn, KMOD = (CMOD XKR) /65536+
(65536CMon)
Then, the process proceeds to the 57th step 357.

The 62nd to 67th steps 362 to 367 store the results of learning control as a correction coefficient KMOD when the boost pressure P2 is stably feedback-controlled in the dead band GP2, and in special operating conditions. This is to prevent the KMOD from being stored and adversely affect the operating condition.

As detailed above, in the low-speed operating range of the engine, setting at least one of the valve opening angle and lift to a relatively small value suppresses the intake air blowback phenomenon and increases intake air filling efficiency. In addition, in order to ensure the necessary intake air amount in the high-speed operating range of the engine, it is advantageous to set at least one of the valve opening angle and lift to a relatively large value. . That is, the output characteristics relative to the rotational speed of the engine are largely controlled by the cam profile. Therefore, in an engine that operates valves by switching between two different cam profiles as shown in the second embodiment, it is possible to have two different output characteristics. However, on the other hand,
As described above, the characteristic of the output torque with respect to the engine rotational speed draws a curve like a mountain, so in the case of an engine having the above configuration, it is impossible to avoid the occurrence of a valley in the torque regardless of the driver's intention.

Therefore, in the present invention, when the boost pressure change rate ΔP2 is in a negative state, that is, the output torque tends to decrease, using the set addition duty DTRB searched in the 29th step 329, the basic duty is automatically changed to DM. The amount is increased to compensate for the drop in output torque caused by changing valve timing.

[Effects of the Invention] As described above, according to the present invention, the rate of change in supercharging pressure is constantly detected and optimal supercharging pressure control is performed in response to the load condition. Fluctuations in output torque can be compensated for by supercharging. Therefore, it is extremely effective in flattening the output torque characteristics of an engine equipped with a valve operation state switching device and a variable capacity supercharger, and improving the output torque characteristics in all rotational speed ranges.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an engine control system based on the present invention. FIG. 2 is a configuration diagram around the valve train mechanism. FIG. 3 is an explanatory diagram of the mechanism of the variable displacement turbocharger. Figures m4a to 4C are flowcharts of control programs related to valve timing switching. Figures 5a and 5b are flowcharts of a control program related to varying the supercharging pressure. 6 to 11 are flowcharts of each subroutine related to the program. 1...Engine body 2...Intake port 3...
Intake manifold 4...Intake pipe 5...Throttle body 6...Intercooler 7...Variable displacement turbocharger 8...Compressor section 9...Air cleaner 10.
・・Exhaust port 11・・Exhaust manifold 12・
...Turbine part 13...Catalytic converter 14...
- Valve mechanism 15...Oil pump 16...Solenoid valve 17...Switching control valve 18...Actuator 19...Water pump 20...Radiator 21...Electronic control circuit 22... oil pressure switch
23...Oxygen concentration sensor 24...Engine rotation sensor 25...Cooling water temperature sensor 26...Automatic transmission 27...
...Intake temperature sensor 28...Intake pressure sensor 29...
Throttle valve opening sensor 30...Supercharging pressure sensor 31...Intake pressure sensor 32
...Vehicle speed sensor 33...Fuel injection valves 34, 35
...Solenoid valve 40...Rocker shaft 41-43.
...Rocker arm 45...Camshaft 46a, 46b...Low speed cam 47...High speed cam 50a, 50b...Intake valve 51...Connection switching device 83...Turbine wheel 84... Fixed vane 87...Movable vane 104
...Diaphragm 105...Negative pressure chamber 106...Positive pressure chamber O2...Hydraulic pressure signal 02...Oxygen concentration N8...
・Engine rotation speed Tw・・Cooling water temperature P・・Parking range signal N
...New 1~Ral range signal TA...Intake temperature PR...Intake negative pressure 01...
・Thrower)・Le valve opening P2...Supercharging pressure PA...Atmospheric pressure ■...Traveling speed DM...Basic duty P2+1G・
...High boost pressure judgment guard value D1...Setting subtraction duty DTRB...Setting addition duty P2. ．． ...1" standard boost pressure △, 2" boost pressure change rate Applicant: Book 1 [1 Giken Kogyo Co., Ltd.]
Attorney Patent Attorney Hiro Shima Figure 8 Figure 9 Procedural Amendment (Method) % Formula % Display of Case 1988 Patent Application No. 328553 2゜Name of Invention 4゜Agent's Residence〒102 Iidabashi, Chiyoda-ku, Tokyo 1 6゜Number of inventions increased by the amendment 7゜Detailed description of the invention in the specification subject to the amendment 8゜Contents of the amendment Line break after “Control device for...” on page 2, line 14 of the specification and insert "3. Detailed description of the invention."

Claims (3)

[Claims] (1) A switching device for varying the operating state of at least one of the intake valve and the exhaust valve, a variable capacity supercharger, and the switching device in accordance with the operating state of the engine including at least the engine rotation speed. a control means for switching the device and varying the supercharging capacity of the supercharger based on a basic supercharging pressure control amount corresponding to the operating state of the engine including at least the engine rotation speed; An engine control device, wherein the basic boost pressure control amount is corrected by the control means in response to a rate of change in boost pressure generated by a charger. (2) Control of the engine according to claim 1, wherein the basic boost pressure control amount is corrected by the control means in a state where the switching device corresponds to at least a low speed operating range. Device. (3) a switching device for varying the operating state of at least one of the intake valve and the exhaust valve; a variable capacity supercharger; and a control means for switching the device and varying the supercharging capacity of the supercharger based on a basic boost pressure control amount corresponding to the operating state of the engine including at least the engine rotation speed, the switching When the device is in a state corresponding to at least a low speed operating range, the control means corrects the basic boost pressure control amount in response to the engine rotation speed and the rate of change in boost pressure generated by the supercharger. An engine control device characterized by: