JPH02207137A - Control device for engine - Google Patents

Abstract

PURPOSE:To increase suction filling efficiency by controlling the operation of a cooling water circulating pump related with a suction cooling means on the downstream side of a supercharger in response to the state of a valve system switching means in an engine having the valve system switching means for changing the valve operation state and the supercharger. CONSTITUTION:The compressor section 8 of a turbo-charger 7 is provided on a suction manifold 3 connected to suction ports 2 of individual cylinders, and a short pipe 6a with a suction cooling device 5 and a long pipe 6b bypassing the short pipe 6a are provided. The suction cooling device 5 cools the suction air by circulating the cooling water between it and a radiator 20 via the operation of a water pump 19. A valve system 14 changing the valve timing of a suction valve and an exhaust valve by changing the oil pressure from an oil pump 15 via a solenoid valve 16 and a switching control valve is provided. The water pump 19 is controlled in response to the valve timing switching state of the valve system 14 in this engine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to an engine control device having a valve operation state switching means and a supercharger.

<Prior art> By changing at least one of the operating angle and lift of the intake valve or exhaust valve provided for each cylinder mainly in accordance with the engine rotation speed, the combustion chamber can be controlled over a wider operating range. A valve operating mechanism equipped with a valve operation state switching device that improves the filling efficiency of air-fuel mixture into the air-fuel mixture has been proposed, for example, in Japanese Patent Laid-Open No. 16111/1983. If such an engine is equipped with a supercharger, further improvement in engine performance can be expected.

On the other hand, in internal combustion engines equipped with a supercharger, in order to avoid a decrease in charging efficiency due to an increase in intake air temperature due to intake air compression, intake air cooling is activated according to the intake air temperature. For example, the technology of installing a device downstream of a turbocharger was disclosed in Japanese Patent Application Laid-Open No.
It has been proposed in Publication No. 8-150022 and the like.

<Problems to be Solved by the Invention> However, when the operating condition of the intake air cooling device in an internal combustion engine equipped with a valve operation state switching device is only the intake air temperature, the intake air charging efficiency is reduced by switching the valve operation state. Since the supercharging pressure generated by the supercharger also changes, it is difficult to accurately and quickly follow these changes. Therefore, it has been extremely difficult to perform optimal intake control for each operating state.

In view of these disadvantages, the main object of the present invention is to provide an engine that can relatively easily achieve further performance improvement by combining a valve operation state switching device, a supercharger, and an intake air cooling device. The purpose of this invention is to provide a control device.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, such an object is to provide a valve operating switching means for varying the valve operating state of at least one of an intake valve and an exhaust valve. and a supercharger, a water-cooled intake air cooling means provided in an intake passage downstream of the supercharger, a pump for circulating cooling water to the intake air cooling means, and the pump. and an electronic control circuit for controlling the operation of the valve-operating switching means and controlling the switching of the valve-operating switching means, the engine control device characterized in that the operation of the pump is controlled in accordance with the state of the valve-operating switching means. Alternatively, a short intake passage and a long intake passage are located downstream of the supercharger and are parallel to each other and connect the supercharger and the intake port of the engine, and the short intake passage and the long intake passage are It has a switching valve for selectively communicating only one or the other, and an electronic control circuit that performs switching control of the switching valve and the valve operating switching means. This is achieved by providing an engine control device characterized in that selection control of the switching valve is performed.

<Operation> In this way, the operating state can be accurately grasped based on the operating state of the valve or the supercharging state.

Therefore, it becomes possible to optimally control the temperature of supercharging air according to the operating state of the engine. In particular, when the valve operating state corresponds to a low speed range, an inertia effect can be added by using a long intake passage, and when the valve operation state corresponds to a relatively high speed range, intake resistance can be reduced by using a short intake passage. can be achieved.

Embodiments The present invention will now be described in detail with reference to specific embodiments 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 the intake port 2 of each cylinder in an engine body 1 consisting of an in-line four-cylinder engine includes a throttle body 4, a short pipe 6a provided with an intake air cooling device 5, and a short pipe 6a provided with the throttle body 4, The long pipe line 6b that bypasses the air, the compressor section 8 of the turbocharger 7, and the air cleaner 9 are connected in this order. Further, a turbine section 12 of a turbocharger 7 and a catalytic converter 13 are connected to an exhaust manifold 11 connected to an exhaust port 10 of each cylinder. Here, the long pipe line 6a has a relatively small cross-sectional area in order to obtain an intake inertia effect in an operating region where the intake air flow rate is relatively small, and the short pipe line 6a has a relatively small cross-sectional area to reduce the flow resistance caused by the intake air cooling device 5. The cross-sectional area is said to be relatively large enough to compensate for this.

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.

At the part where the short pipe line 6a and the long pipe line 6b are connected to each other,
Switching valves 18a and 18b are provided respectively, and by selecting the positions of these switching valves 18a and 18b using separate control means, only one of the short pipe line 6a and the long pipe line 6b can be used. The intake air that has passed through the turbocharger 7 can be introduced into the intake port 2. This turbocharger 7 is equipped with an electric water pump 19.
As a result, the intake air cooling device 6 is cooled together with the cooling water that flows back through the radiator 20 which 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, etc. by an electronic control circuit 21.

The electronic control circuit 2] includes an oil pressure signal OF 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 1, and an engine rotation sensor 24. rotational speed signal NE from the engine body 1, and a water temperature signal Tw from the cooling water temperature sensor 25 for detecting the water temperature in the water jacket of the engine body 1.
, a parking and neutral signal P-N in the shift position of the automatic transmission 26, an intake air temperature signal TA from the intake air temperature sensor 27 provided on the upstream side of the throttle body 4 in the intake passage, and an intake air temperature signal TA on the downstream side of the throttle body 4. Intake pressure signal P B s from the provided intake pressure sensor 28
Valve opening signal θTit from throttle valve opening sensor 29
s Boost pressure signal from a boost pressure sensor 30 provided downstream of the compressor 8 in the intake passage P2N Atmospheric pressure sensor 31 provided in the intake passage between the air cleaner 9 and the compressor 8 of the turbocharger 7 An atmospheric pressure signal PA from the vehicle speed sensor 32 and a traveling speed signal V from the vehicle speed sensor 32 are input, respectively. Based on each of these input signals, a solenoid valve 16 for switching valve timing, a fuel injection valve 33 for injecting fuel into the intake port 2, and a switching valve 18a for switching between the short pipe line 6a and the long pipe line 6b.・18b
The operations of actuators 34a and 34b for driving are controlled by output signals from 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.

Rocker shirt fixed to the cylinder head!・40 has three rocker arms 41, 42, 43 for each cylinder.
are adjacent to each other and are pivotally supported so as to be swingable and relative angularly displaceable. These rocker arms 41, 42, 43
A camshaft 45 is rotatably supported above 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 three sides 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 upper 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 hook arms 41, 42. On the other hand, the 1st and 20th
The 30th claw arm 43, which is disposed between the claw 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, which constantly applies biasing force in two directions. It is being

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.

A bottomed first guide hole 52 that opens toward the 30th hook arm 43 is provided in the 10th hook shaft 41 .
0, and in this first guide hole 52,
The first switching pin 53 is slidingly engaged. A hydraulic chamber 54 is defined at the bottom of the first guide hole 52.
4 communicates with an oil supply passage 57 provided inside the rocker shaft 40 via an oil passage 55 provided inside the tenth lever arm 41 and an oil supply hole 56 opened on the circumference of the hollow rocker shaft 40. There is.

The 30th lever arm 43 has a second guide hole 58 which is parallel to the rocker shaft 40 and has the same diameter and is concentric with the first guide hole 52 in the rest position where the cam slipper is in sliding contact with the base circle of the high-speed cam 47. A second switching pin 59 that extends through the pin 59 and has one end in contact with the first switching pin 53 is slidably fitted inside the pin 59 .

Similarly, a third guide hole 60 with a bottom is bored in the 20th hook arm 42, and a stopper pin 61 whose one end is brought into contact with the other end of the second switching pin 59 is slidably fitted inside the third guide hole 60.

The stopper bin 61 has its shaft portion 63 fitted into a guide sleeve 62 fitted to the bottom of the third guide hole 60, and is always resiliently biased toward the 30th hook arm 43 by a return spring 64.

By moving these five first and second switching pins 53 in the left and right direction in FIG. 2 by the action of the hydraulic pressure introduced into the hydraulic chamber 54 and the biasing force of the return spring 64, Since each of the rocker arms 41 to 43 shown in FIG. 50a・5
It is possible to selectively switch between states in which ob can be driven to open the valves 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 switching control valve 17 described above is attached to the cylinder head, and is driven to open by the oil pressure supplied via the electromagnetic valve 16 which is controlled to open and close by the control signal described above. It has a built-in spool valve 70 which is resiliently biased to a normally closed position. 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 outflow port 73 communicates with a drain port 75 that opens into the upper space of the cylinder head, and the oil pressure in the oil supply path 57 becomes low. Therefore, no hydraulic pressure is supplied to the oil supply path 57, and each of the bins 53 and 59 is in a position where it is urged toward the hydraulic chamber 54 by the return spring 64, and each rocker arm is driven separately by a corresponding cam, and is rotated at a relative angle to each other. Displace. 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 boat 73 are connected to the spool valve 70.
The outflow port 73 communicates with the annular groove 77 of the
The communication between the lubricating oil passage 66 and the drain port 75 is cut off, and oil is force-fed from the lubricating oil passage 66 to the oil supply passage 57. This results in the 10th
When hydraulic pressure is supplied to the hydraulic chamber 54 of the lever arm 41, the first and second switching pins 53 and 59 move into the second guide hole 58 and the third guide hole 60, respectively, against the urging force of the return spring 64. Fit each rocker arm 41 to 4
3 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 passes through the downstream end of the oil supply passage 57 to the oil supply pipe 4 for high-speed lubricating oil.
9, the high-speed cam 47 and the 30th lug arm 4
Lubricate the sliding surface with 3.

The spool valve 70 described above is switched to the open position against the biasing force of the return spring 69 by pilot pressure input to the upper end side of the spool valve 70 via a pilot oil path 78 branched from the inflow boat 72. The normally-closed solenoid valve 16 described above is interposed in the pilot oil passage 78, and energization of the solenoid of the solenoid valve 16 is controlled by an output signal from the electronic control circuit 21 to open the solenoid valve 16. When the solenoid valve 16 is closed, the spool valve 70 is switched to the open position and the valve timing is switched to high-speed valve timing as described above.
0 is switched to the closed position and the 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 boat 73 and turns on when the pressure is low and turns off when the pressure is high.
Confirmed by.

Next, a control program incorporated into the electronic control circuit 21 to control the solenoid valve 16 for valve timing switching will be explained with reference mainly to FIG. 3a.

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, a second step 202 sets an elapsed time TDS (for example, 5 seconds) after engine start, and prepares to start a time measurement operation after engine start. Next, in a third step 203, a valve closing command is issued to the solenoid valve 16,
Select low speed valve timing operation. Then, in a fourth step 204, an elapsed time TDHVT (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 a fifth step 205, the basic fuel injection amount map and ignition timing map used in the fuel injection control routine are map T! corresponding to those of low-speed valve timing operation, respectively. Select L・θIGL and proceed to the 6th step 2
Rev limiter value NH for fuel cut at 06
Set p6 to the value NIIF corresponding to low-speed valve timing operation.
Set to CL.

By the way, the fuel injection amount T ou'r is given by the following equation, assuming that the basic fuel injection amount is T1, the correction coefficient is 1, and the constant term is 2.

TOUT=KIT■+In addition, the intake temperature correction coefficient KTA and water temperature correction coefficient K are used to increase the amount of fuel when the intake air temperature TA and cooling water temperature Tw are low.
, w, high load increase coefficient KWOT to increase the amount of fuel in a predetermined high load area defined by engine speed NE, intake negative pressure PB1 throttle opening θTH 1 02 feedback area in a relatively low rotation range (for example 4000 RPM) A feedback correction coefficient KO2, etc. is included for correcting the deviation of the air-fuel ratio from the stoichiometric air-fuel ratio, and 2 also includes:
This includes an acceleration increase constant that increases the amount of fuel during acceleration. The basic fuel injection amount T is the amount of air intake into the cylinder in each operating state defined by the engine speed N8 and the intake negative pressure PB, so that the intake air-fuel mixture reaches a target air-fuel ratio close to the stoichiometric air-fuel ratio. It is set based on experimental values so that
The T1 map includes a T1L map for low-speed valve timing operation, and a T1.L map for high-speed valve timing operation.
Two sets of one map and one map are stored in the electronic control circuit 21.

Incidentally, 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 N, which causes valve jump, decreases.

Therefore, the allowable rotational speeds are 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 NCL during low-speed valve timing operation is set to a relatively low value. (for example, 7500 RPM), and the rev limiter value N+rpco 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 being 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, the process proceeds to the second step 208 in the eighth step 208.
The remaining time of the post-start elapsed time TosT set in step 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 Tw.

(for example, 60° C.), that is, whether or not warming has been completed. If it is determined that TW is Twl, the process proceeds to the third step 203, and if T≧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 ~5km/h)
Determine whether the following is true. If V<Vl, the process proceeds to the third step 203, and if V≧V1, it is determined in the eleventh 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 at the 11th step 211 that the vehicle is not a manual transmission vehicle, that is, it is an automatic transmission vehicle AT, it is determined at a 12th step 212 whether the shift position is in the parking P or neutral N range. P-
If it is in the N range, it is determined in a thirteenth step 213 whether or not a T□ 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 the 14th step 214, the lower limit rotational speed NEI (for example, 4800 to 4600 RPM including hysteresis) is set such that the output in low-speed valve timing operation always exceeds the output in high-speed valve timing operation. and the current engine rotational speed N5.

If it is determined that NE<NEI, the first
At step 5 215, similarly to step 13 213, it is determined whether the T1 map for high-speed valve timing operation was selected last time, and if it has not been selected, the process proceeds to step 3 203.

According to the flow up to this point, even if the engine rotation speed N8 is high, if the engine is stopped, or if it is running at a slow or low speed and has not yet been driven at high speed, then low-speed valve timing operation is performed. You can see that it is set to .

On the other hand, if it is determined in the 14th step 214 that NE≧NE1, then in the 16th step 216, the TIL map and the TIH map are searched according to the subroutine shown in FIG. 3b, and the current engine rotational speed N2 and T according to the intake negative pressure PB,! , and the T1H value, and then in the 17th step 217, according to the subroutine shown in FIG. Calculate the Tv value according to NE.

Here, T, -・T11. The value of is used to determine whether or not a command to open the solenoid valve 16 was issued last time. 16th step 21
The T1L value used in step 6 is the value searched from the T, L map, and if a valve opening command is issued, the TiC value is processed to be the value obtained by subtracting a predetermined hysteresis amount ΔT1 from the search value, and Similarly, regarding the calculation process of the Tv work value in the 17th step 217, it is determined whether or not a valve opening command for the solenoid valve 16 was issued last time, and if the valve opening command was not issued, the 17th step 217 The Ti value used in step 217 is
The value is calculated from the v1 table, and if a valve opening command is issued, the Tv□ value is processed to be the value obtained by subtracting a predetermined hysteresis amount ΔTv□ from the calculated value, thereby setting the valve timing switching point. Hysteresis is added to the switching characteristics of the fuel injection amount at the same time.

Next, in the 18th step 218, this TvT value and the previous fuel injection amount T are determined. Compare with U-engineering. T here. Uluku TV
If it is determined as T, in the nineteenth step 219,
Upper limit engine rotational speed N where the output during high-speed valve timing operation always exceeds the output during low-speed valve timing operation
E2 (including hysteresis, e.g. 5900-5700R)
PM) and the current engine rotational speed N2.

If it is determined that N8<NE□, then in the 20th step 220, the T1.
value and T17. If it is determined that T IL > T Ill, a valve closing command is issued to the solenoid valve 16 in a 21st step 221, that is, 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 Tll1 map was selected last time, that is, when the vehicle is in a low-load, low-speed state after high-speed driving, the process proceeds to the 21st step 221. move on.

On the other hand, if it is determined in the 18th step 218 that ToUT≧TvT, then in the 19th step 219 N8≧N6□
If it is determined that TIL≦, in the 20th step 220
If it is determined that T, .
In step 3, set the flag indicating the high-speed valve timing operation state to Fl (VT=1).From the flow up to this point, depending on the engine rotation speed NE and the required fuel injection amount,
It can be seen that the valve timing switching point is determined.

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
Optimum switching control can be achieved through this process.

After selecting the high-speed valve timing operation, in a twenty-fourth step 224, a signal from the oil pressure switch 22 for checking the operating status of the switching control valve 17 is determined. If it is determined that the oil pressure switch 22 is off, that is, that the oil pressure is acting on the connection switching device 51, the delay after the connection switching device is activated, which is set in the fourth step 204, is
The remaining time of time TOIIVT is determined in a twenty-fifth step 225. If it is determined that the TDHV knee is 0 here, in the 26th step 226, the elapsed time TDLVT (for example, 0°2 seconds) after switching to low-speed valve timing operation is set, and the delay time measurement operation after switching is performed. Make preparations. Next, at the 27th step 227, the fuel injection amount T I H map and ignition timing θlG11 corresponding to the high-speed valve timing operation are selected, and at the same time, at the 28th step 228, the rev limiter value NIIFC is set to NIIFCI+ for the high-speed valve timing operation.

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 TI)1. The remaining time of VT is read at the 30th step 230, and if it is T, Lv7-Q, the 4th step
Proceed to step 204.

If the oil pressure switch signal OP is not turned off at the 24th step 224 even though the low speed valve timing operation has been switched to the high speed valve timing operation in this way, the process proceeds to a 30th step 230, where the oil pressure switch signal OP is switched off. 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 became 0°. If the valve is not turned on, the process proceeds to step 225, and the operating condition at high-speed valve timing is maintained until the oil pressure switch signal OP is turned off.

Also, the setting time T DH of the dual switching delay timer set in the fourth and 26th steps 204 and 226 described above.
VT " T LHVT is the response time from when the solenoid valve 16 operates and the spool valve 70 of the switching control valve 17 moves to when the oil pressure of the oil supply passage 57 changes and the switching operation of the switching pins of all cylinders is completed. Even if the start of the switching operation is confirmed from the oil pressure switch signal O1, when switching from high speed to low speed, T DLVT = 0.
, When switching from low speed to high speed, until Tut and vr = 0, it is assumed that the valve timing of all cylinders has not been changed yet, and operation with fuel injection amount control before the valve timing change command is maintained. be done.

Note that if the TIH map was not previously selected in the 13th step 213 and the 15th step 215, that is, immediately after the start of driving or during acceleration, the low-speed valve timing operation is set without checking the oil pressure switch signal O1. However, this is a countermeasure in consideration of the adverse effects that may occur if the signal remains off due to a defect in the oil pressure switch 22 or the like.

Next, the operation control of the water pump 19 for circulating the cooling water to the intake air cooling device 5 or the short pipe line and the long pipe line 6a.
A control program incorporated into the electronic control circuit 12 to control the actuators 34a and 34b for driving the switching valves 18a and 18b that select communication with the electronic control circuit 12 will be described with reference to FIG.

In a first step 301, each data, namely, water temperature T7, intake air temperature T^, engine speed NE, and actual supercharging pressure change rate ΔP2 are read. The supercharging pressure change rate ΔP2 is determined by the difference between the current supercharging pressure P2N and the six previous supercharging pressure P2N-6 (ΔP2 = P2N P2N-6).

That is, the main routine shown in FIG. 4 is updated by the TDC signal, but if the TDC signal is sent only once, the boost pressure change rate Δ
Since P2 is too small, in order to accurately read the boost pressure behavior, that is, the rate of change in boost pressure ΔP2, we need to read the boost pressure P 2N from the previous 6 times.
-6 is calculated.

Next, in a second step 302, it is determined whether the engine rotational speed N8 exceeds a predetermined reference value N (for example, 400 rpm). This is a measure to determine whether or not the engine has completed cranking, and here N
11: <No, that is, if it is determined that cranking is in progress, proceed to the third step 303, issue a stop command to the water pump 19, and in the fourth step 304, the long pipe line 6b side with a relatively small diameter is turned off. A drive command is issued to the switching valves 18a and 18b so as to communicate with each other. NF again! ≧NI! A1, that is, if it is determined that it is after the completion of cranking, then in a fifth step 305, it is determined whether a predetermined time has elapsed after starting the engine, by, for example, counting TDC pulses. Then, in the third step 303, the stop command to the water pump 19 is maintained until the predetermined time has elapsed, and in the fourth step 304, the communication of the long pipe line 6b with a relatively small diameter is maintained, and the predetermined time is After the 6th step 3
Proceed to 06.

At a sixth step 306, the warm-up state is determined by comparing the current water temperature Tw with a predetermined reference value Two (for example, 60° C.). Here, if Tw<Twl, that is, it is determined that the warm-up is in progress, the process proceeds to the third step 303, and Tw≧Tw1,
That is, if it is determined that warm-up is complete, the seventh step 307
Proceed to.

In a seventh step 307, the current intake air temperature TA is compared with a set low air temperature TAL (for example, 20° C.).

If it is determined that TA is TAL, the process advances to the third step 303. If it is determined that TA≧TAL, the process proceeds to an eighth step 308, where the current intake air temperature TA is compared with a set high intake air temperature TAH (for example, 100° C.). If it is determined that TA≧TAH, proceed to the ninth step 3.
At step 09, a start command is issued to the water pump 19 to circulate the cooling water in the intake air cooling device 5 to cool the intake air, and at step 10, the short pipe line 6 with a relatively large diameter is
Select the connection on the a side. If it is determined that TA is less than TAL, the flag FHVT of the 23rd step 223 in the valve timing switching control program is determined in the 11th step 311.

If it is determined at the 11th step 311 that FIIVT=1, that is, the high-speed valve timing operation state is in effect, the process proceeds to the ninth step 309, and it is also determined that FHVT=O1, that is, the low-speed valve timing operation state is in effect. If so, in the next twelfth step 312, the current rate of change ΔP2 of the supercharging pressure P2 is compared with the set rate of change ΔP2A. However, the set rate of change ΔP2^ is the rate of change that corresponds to the rate of change in supercharging pressure ΔP2 and that produces sufficient supercharging efficiency when the supercharging pressure P2 passes the so-called intercept point where it starts to rise quickly. This is set in advance. Here, if it is determined that ΔP2<ΔP2A,
Proceeding to the third step 303, if it is determined that ΔP2≧ΔP2A, in the thirteenth step 313, the water pump 1
9 is issued, and in a fourteenth step 314, communication on the relatively large diameter short pipe line 6a side is selected.

Next, the operation procedure of the above embodiment will be explained.

During startup, warm-up, or low intake air temperature, the engine speed N8 is relatively unstable, and when the boost pressure P2 has not reached the predetermined value, Since the intake air compression by the feeder is small, the intake air temperature TA also does not rise. Therefore, by not operating the water pump 19 unnecessarily and preventing overcooling of the intake air, wasteful power consumption of the battery is prevented, which in turn leads to improvement in engine durability. At the same time, in the engine state described above, low-speed valve timing operation is performed, and in combination with the intake inertia effect obtained by passing through the long pipe 6b, a further increase in output torque can be obtained.

After a complete start and completion of warm-up, or at a high intake temperature, or during high-speed valve timing operation, the required output is relatively large, but the supercharging pressure P2 also becomes relatively higher, and the rate of increase in the intake temperature TA also increases. It is considered to be relatively high. Therefore, by operating the water pump 19 during high-speed valve timing operation, the increase in intake air temperature TA is suppressed, and the intake air filling efficiency is maintained at a high level.

If the intake air temperature TA is within a predetermined range and the supercharging effect is noticeable during low-speed valve timing operation, switching to the relatively large-diameter short pipe 6a allows relatively high speed and large intake flow rate. is ensured, and an increase in output in the medium speed range is achieved.

As described above, by detecting the intake air temperature, the operating state of the valve mechanism, and the supercharging state, it is possible to perform optimal intake control over the entire operating range.

In the above embodiment, the intake air cooling device water pump 1
Although the intermittent control of 9 and the selection of the intake pipe length are controlled in parallel, only one of them may be controlled, or they may be controlled individually with other factors taken into consideration. Further, although the explanation was omitted in the above embodiment, the turbocharger used in this system uses a known intake pressure control means such as an exhaust pressure wastegate method, an intake pressure relief method, or an A/R variable method. It goes without saying that the overall control is performed by adding .

[Effects of the Invention] As described above, according to the present invention, intake air cooling control and/or intake pipe length selection control is performed in response to switching of valve timing and supercharging state, which improves intake air filling efficiency. This will have an extremely significant effect in planning optimization at a higher level.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram of the engine control system based on the present invention. Figure 2 is a configuration diagram of the valve train system. Figures 3a to 3c are control diagrams related to valve timing switching. This is a flowchart of the program. Fig. 4 is a flowchart of a control program related to intermittent switching of the water pump for the intake air cooling system or the bypass passage. 1... Engine body 2... Intake boat 3...
Intake manifold 4...Throttle body 5...Intake air cooling device 6a...Short pipe line 6b...Long pipe line
7...Turbocharger 8...Compressor part 9...Air cleaner 10...Exhaust boat 11
...Exhaust manifold 12...Turbine part 13
... Catalytic converter 14 ... Valve mechanism 15.
...Oil pump 16...Solenoid valve 17...
Switching control valves 18a, 18b...Switching valve 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 valve 34a.3
4b...Actuator 40...Rocker shafts 41-43...Rocker arm 45...Camshafts 46a, 46b...Low speed cam 47...High speed cam 50a, 50b...Intake valve 7w P . A...Connection switching device...Cooling water temperature...Intake negative pressure...Atmospheric pressure NE...Engine speed TA...Intake temperature P2...Supercharging pressure

Claims (3)

[Claims] (1) A valve operating switching means for varying the operating state of at least one of the intake valve and the exhaust valve, and a supercharger;
A water-cooled intake air cooling means provided in the intake passage on the downstream side of the supercharger, a pump for circulating cooling water to the intake air cooling means, operation control of the pump, and switching control of the valve operating switching means. 1. An engine control device, comprising: an electronic control circuit for controlling the operation of the pump in accordance with a state of the valve operating switching means. (2) a valve operating switching means for varying the operating state of at least one of the intake valve and the exhaust valve; and a supercharger;
Either a short intake passage and a long intake passage that are located downstream of the supercharger and are parallel to each other and connect the supercharger and an intake port of the engine, or the short intake passage or the long intake passage. a switching valve for selectively communicating only one side;
Control of an engine, comprising: an electronic control circuit that performs switching control of the switching valve and the valve operating switching means, and wherein selection control of the switching valve is performed in accordance with a state of the valve operating switching means. Device. (3) The engine control device according to claim 2, wherein the switching valve is controlled in response to a rate of change in boost pressure.