JPH04136437A - Controller of engine - Google Patents

Abstract

PURPOSE:To prevent the fluctuation of an engine control quantity so as to eliminate torque shock by detecting viscosity of operation oil in a hydraulic operational mechanism in a valve timing variable means, so as to set a delay time according to the viscosity, and varying the control logic of an engine control means after the lapse of the delay time. CONSTITUTION:It is judged by an ECU 36 whether the present situation is under the transient condition of valve timing switching and when it is under the transient condition, control of an engine ignition timing and a fuel injection quantity in compliance with the viscosity of engine oil is performed in a device in which a valve timing variation mechanism 27 for changing the close timing of an intake valve 4 is set on a cam shaft 11 for the intake side in relation to an intake valve 4, and a valve open/close timing is changed by switching action from the oil pressure supply to the mechanism 27 to return release by an oil pressure control means 26. The oil pressure P and oil temperature Th of operation oil in a valve timing variation mechanism are respectively calculated, and the responsing times of a valve timing switching mechanism is response to the calculated values P, Th are calculated, and the optimum ignition timing and fuel injection quantity are finally calculated after the lapse of responsing time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control device equipped with a variable valve timing mechanism.

(Prior Art) Generally, it is desirable to set the opening/closing timing of the intake valve and exhaust valve of the engine in various ways depending on the operating condition.
Doing so would complicate the structure of the valve mechanism, so in normal engines, the opening and closing timings are uniformly set in consideration of cost considerations.

However, with the trend toward higher-end automobiles, recently, as described in Japanese Patent Application Laid-Open No. 60-27711, the opening/closing timing of the intake valve or exhaust valve can be changed using a valve timing changing means. Various systems have been put into practical use in which the intake and exhaust overlap periods are set larger during high loads than during low loads.

At low loads, the intake flow rate is small, so if the intake/exhaust overlap period is too large, the amount of residual burnt gas will increase and combustibility will decrease, which is undesirable.However, at high loads, the intake/exhaust overlap period should be increased. Since the intake flow rate is also large, the amount of residual burnt gas does not increase much, and the intake air filling efficiency increases, making it possible to increase the output.

The switching of the valve timing by the valve timing changing means is generally performed when the engine speed reaches a predetermined switching speed. For example, curve A is the torque characteristic at the stoichiometric air-fuel ratio (A/F = 1.4.7) produced by a low-speed cam with a small intake/exhaust overlap period, and curve A is the torque characteristic produced by a high-speed cam with a large intake/exhaust overlap period. Assuming that curve B represents the torque characteristic at the stoichiometric air-fuel ratio (A/F = 14.7), the engine at point P where curve A and curve B intersect (that is, the point where the torques are equal) The valve timing is switched at the rotation speed Nc. That is, when the engine speed N<Nc, the low speed cam is selected, and when N>NC, the high speed cam is selected.

The switching of each cam (advance/retard) is performed using a variable valve timing mechanism using hydraulic pressure, such as the configuration shown in FIG. 2, which will be described later.

(Problem to be Solved by the Invention) However, in the case of an engine in which the valve timing is changed in two stages, for example, high-speed advance and low-speed retard, using hydraulic means as described above, the valve timing switching transient For example, if the viscosity or pressure of the working oil differs during the time (several seconds are required), there is a problem that the length of the transient time (response time) itself changes. As a result, problems such as ignition timing and fuel injection amount becoming inappropriate during that period, resulting in fluctuations in engine output and torque shock, and worsening of exhaust emissions due to changes in the air-fuel ratio. be.

(Means for Solving the Problems) Each of the inventions recited in claims 1 to 3 of the present application has been made for the purpose of solving the above-mentioned problems, and is configured as follows. There is.

(1) Structure of the invention as claimed in claim 1 The invention as claimed in claim 1 provides a variable valve timing means for changing the valve timing of an engine using a hydraulic actuation mechanism, and a valve timing variable means for changing the valve timing of an engine using a hydraulic actuation mechanism, and an operation of the engine based on a predetermined control logic. An engine comprising: an engine control means for controlling a state; and a hydraulic oil viscosity detection means for detecting the viscosity of the hydraulic oil of the hydraulic operating mechanism; The present invention is characterized by further comprising a control logic changing means for setting a delay time and changing the control logic of the engine control means after the delay time.

(2) Structure of the invention according to claim 2 The invention according to claim 2 has the basic structure of the invention according to claim 1, and the control logic of the engine control means in the structure is for controlling the ignition timing. It is characterized by certain things.

(3) Structure of the invention according to claim 3 The invention according to claim 3 has the basic structure of the invention according to claim 1, and the control logic of the engine control means in this structure is control of the fuel injection amount. It is characterized by this.

(Function) Each of the inventions according to claims 1 to 3 of the present application configured as described above exhibits the following functions corresponding to each of the configurations.

(1) Effect of the invention claimed in claim 1 As described above, in the configuration of the invention claimed in claim 1, the valve timing of the engine control means is changed over, for example, into two high and low stages by the hydraulically actuated valve timing variable means. In an engine in which the operating state of the engine is controlled by a predetermined control logic, the viscosity of the hydraulic oil in the hydraulic operating mechanism of the valve timing variable means is detected, and the viscosity of the hydraulic oil is adjusted based on the detected viscosity of the hydraulic oil. Correspondingly, the control logic of the engine control means is changed with a predetermined delay time.

(2) Effect of the invention claimed in claim 2 As described above, the configuration of the invention claimed in claim 2 uses the configuration of the invention claimed in claim 1 as a basic configuration, and the engine control means which is one of the constituent elements thereof. The control logic specifically controls the ignition timing of the engine.

Therefore, the control logic changed by the control logic changing means changes the ignition timing, that is, advances or retards the ignition timing, resulting in good responsiveness (the operating state of the engine is controlled).

(3) Effect of the invention according to claim 3 As described above (, in the configuration of the invention according to claim 3, the configuration of the invention according to claim 1 is the basic configuration, and one of the components is the engine control The control logic of the means specifically controls the amount of fuel supplied to the engine.

Therefore, the control logic changed by the above-mentioned control logic changing means changes the amount of fuel supplied to the engine, that is, corrects rich or lean engine air-fuel ratio, and controls the engine output and exhaust emission state with good responsiveness.

(Effect of the invention) Therefore, claims 1 to 3 of the present application! c! According to each of the inventions listed above, variations in the engine control amount during valve timing switching transients are prevented as much as possible, and effects such as smooth switching without torque shock and prevention of deterioration of exhaust emissions are achieved. can do.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. First, FIG. 1 shows a schematic configuration of a supercharged engine that is the object of an embodiment of the present invention.

In each cylinder 1a of the engine 1, an intake boat 5 that is opened and closed by an intake valve 4 and an exhaust port 7 that is opened and closed by an exhaust valve 6 are provided in a combustion chamber 3 formed above a piston 2.
is open, an intake passage 8 is connected to the intake port 5, and an exhaust passage 9 is connected to the exhaust port 7.

The cylinder head of the engine 1 has one cylinder for each cylinder.
An overhead-type intake-side camshaft 11 for opening and closing the intake valve 4 of each cylinder 1a is provided, and an overhead-type exhaust-side camshaft 12 for driving the exhaust valve 6 of each cylinder 1a to open and close is provided. Both camshafts11.
12 is a cam pulley 13, 1 installed at each end.
3, it is rotationally driven in synchronization with the rotation of the engine output shaft 15 via the timing belt 14.

On the other hand, an air cleaner 18, an intake air amount sensor 19, and a throttle valve 20 are interposed in the intake passage 8 communicating with the intake port 5 from the upstream side, and a compressor 16 of the exhaust turbo supercharger 10 is disposed upstream of the throttle valve 20. is installed. This compressor 16 has a turbine shaft 17
a, the turbine shaft 17a
The intake air is supercharged by the rotational force generated when the engine is rotated by the exhaust energy.

Further, the intake passage 8 downstream of the throttle valve 20 is formed as an independent intake passage 8a whose downstream side of the surge tank 22 is connected to each cylinder 1a, and an injector 23 for supplying fuel to the independent intake passage 8a is disposed. ing.

Further, an intake side shaft 11 for the intake valve 4 is provided.
A variable valve timing mechanism 27 is installed in which changes the opening and closing timing of the valve timing mechanism 27 to change the closing timing of the intake valve 4.

The details of this variable valve timing mechanism 27 will be described later with reference to FIG.
8, and the oil feed passage 2
Three-way solenoid valve 29 (passage switching mechanism) in the middle of 8
An operating signal is output from the engine control unit 36 to the three-way slide/id valve 29 according to the operating state, and a hydraulic control means 26 switches between supplying hydraulic pressure to the variable valve timing mechanism 27 and releasing the hydraulic pressure.
is configured.

Further, the turbine shirt of the exhaust turbo supercharger 10)
A lubrication path for the bearing portion 25 of 17a is connected. That is, the oil pump 24 is located upstream of the open portion of the return side of the three-way solenoid valve 29 of the oil supply passage 28 to the variable valve timing mechanism 27.
Branching from the side, the bearing part 25 of the exhaust turbo supercharger 10
An oil passage 30 is installed leading to the bearing part 25, and the oil is returned to the oil pan 35 of the engine 1 through a return passage 30a.

As shown in FIG. 2, a specific structural example of the three-way valve 29 includes a spool valve 32 inserted into a cylinder 31 and a return spring 33 compressed at one end.
The rod 34a of the drive solenoid 34 is in contact with the other end of the return b which opens the C boat into the cylinder head, which communicates with the oil supply passage 28 for the variable valve timing mechanism 27 according to the movement of the spool valve 32. It is configured to switch the communication to the C port which communicates with the oil pump 24 for boat or engine lubrication.

Note that the C boat is open to the return side, and the spool valve 3
2 movement is allowed. In the figure, a solid line indicates an off state, and a virtual line indicates an on state. In the off state, the C port and the b port communicate with each other, and oil is not supplied to the variable valve timing mechanism 27. On the other hand, in the on state, the spool valve 32
As a result of this movement, the C-boats are brought into communication with the C-boats, and oil from the oil pump 24 is supplied to the variable valve timing mechanism 27, thereby introducing a predetermined hydraulic pressure.

Then, a drive signal is output from the engine control unit 36 to the driving solenoid 34 of the three-way solenoid valve 29 according to the operating state, and as shown in FIG. An ON signal is output to the solenoid valve 29, and hydraulic pressure is introduced into the variable valve timing mechanism 27, and the closing timing rC1 of the intake valve 4 is advanced and closed earlier, as shown by the solid line I in FIG. It operates to increase the intake air filling efficiency. In other low load or high rotation range B, an off signal is output to the three-way solenoid valve 29,
The closing timing I of the intake valve 4 is indicated by the broken line ■ in FIG.
C2 is delayed so that it closes later.

In order to detect the operating state, the engine control unit 35 receives engine load signals such as a load signal from a throttle sensor 38, an oil temperature signal from an oil temperature sensor 39 that detects oil temperature, and an engine speed. On/off signals and the like from the rotation sensor 40 and the engine key switch 41 to be detected are respectively input.

Further, the three-way solenoid valve 29 is provided with the engine 1
When the key switch 41 of the engine is activated from the off state to the on state, that is, at the time of starting, the engine control unit 3
6 outputs an on state, and when the oil supply passage 28 of the part communicating with the oil passage 30 for the exhaust turbo supercharger 10 is placed on the oil return side, it operates in a disconnected state.
It is configured to supply oil whose pressure has increased to the supercharger 10 from the upstream side of this oil return portion.

In other words, point 1 to synthesize. When the key switch 41 is turned on at point t5, an on signal is output to the three-way solenoid valve 29 from point t5.

Then, by cranking the engine 1 at the next 12 points.
starts and the rotation speed increases, while oil pump 2
4, the oil pressure P to the bearing 25 rapidly increases, and the amount of oil supplied to the bearing 25 is ensured.

The operating state immediately after engine startup is a low load region, and based on the operating region shown in FIG. 4, an off signal is output to the three-way solenoid valve 29 to control the intake valve 4 to close slowly. However, when the oil pressure is low as described above, even if the ON signal is output, the variable valve timing mechanism 27 does not operate to close the intake valve 4 early, but maintains the slow (closed) state. The oil pressure increases in response to the increase in engine speed, and at t3 when the engine speed reaches the set speed Ns.
At this point, the ON signal to the three-way renoid valve 29 is stopped. This set engine rotational speed Ns at the time of stop is set to become higher as the oil temperature (water temperature) increases.

The duration of the on signal to the three-way solenoid valve 29 when the engine key switch 41 is turned on as described above may be controlled by the engine speed set to a fixed value, a predetermined time by a timer, or the like.

Next, the detailed structure of the variable valve timing mechanism 27 is as shown in FIG. A cam pulley 13 with which 14 is engaged is attached. This cam pulley 13 is connected to the spacer 5 at the tip of the boss portion 55 that is fixed to the unit.
The proximal end of the boss portion 55 is fixed to a cylindrical connecting member 56 rotatably attached to the intake camshaft 11. An inter-cam gear 57 is spline-coupled to the other end of the connecting member 56 and fixed by a lock nut 58. An inter-cam gear (not shown) fixed to the tip of the exhaust-side camshaft 12 is meshed and connected to the inter-cam gear 57 .

An annular piston 60 is installed inside the boss portion 55 of the cam pulley 13 and between it and the spacer 53 . The piston 60 has a structure in which it is divided into two parts in the axial direction, and both parts are fixed to each other by a plurality of pins 61 arranged at equal intervals in the circumferential direction. Helical splines 62.6 in opposite directions are provided on the inside and outside of the piston 60.
3 is formed. A helical spline 64 is formed on the outside of the spacer 53 with respect to the spline 62 on the inside of the piston 60, and a boss portion 55 of the cam pulley 13 is formed with respect to the spline 63 on the outside of the piston 60.
A helical spline 65 is formed on the inner periphery. The piston 60 is urged toward the distal end side by a spring 66 installed between the piston 60 and the end surface of the connecting member 56.

An oil passage 67 is formed in the intake camshaft 11 along the axis. One end of this oil passage 67 is led out to the outside of the shaft, and communicates with the oil supply passage 28 which passes from the oil pump 24 through the three-way solenoid valve 29.

On the other hand, the cylindrical spacer 53 is fixed to the intake side camshaft 11 with a fixing bolt 69 via a stopper member 68. The fixing bolt 69 is provided with an axial through hole 70 that communicates with the oil passage 67. Further, a lid member 7 is provided at the tip of the host portion 55 of the cam pulley 1.
2, the oil pressure from the oil passage 67 is guided (pressure chambers 71 are provided) facing the head of the piston 60.The oil pressure is introduced into these pressure chambers 71 through the oil passage 67, and the spring When the piston 60 is moved in the axial direction by compressing the piston 66, the spacer 53 and the cam pulley 1, which engage with the splines 62 and 63 in opposite directions formed on the inner and outer circumferences of the piston 60, are moved so that one is relative to the other. As a result, the phase of the intake camshaft 11 integrated with the spacer 53 and the cam pulley 13, that is, the valve timing changes.A cover member 73 is disposed outside the variable valve timing mechanism 27. ing.

The introduction control of the hydraulic pressure is performed by the three-way solenoid valve 29.
This is performed by the engine control unit 36 which outputs a drive signal to the engine.The engine control unit 36 controls the valves corresponding to the current operating state based on the engine load (e.g. throttle opening) and engine speed. The operating range of the variable timing mechanism 27 (see FIG. 4) is determined to switch the communication state of the three-way solenoid valve 29. Also, when the key switch 41 is turned on, the on signal is inputted as described above.

In the embodiment described above, the lubricity of the supercharger 10 is obtained when the key switch 41 is turned on, and the cow-switch 4
The lubricity during the OFF state of 1 is also improved.

That is, even if the key switch 41 is turned off and the engine 1 is stopped, the turbine 17 of the supercharger 10 continues to rotate for a while due to inertia, and in this state, as the oil pump 24 stops, the oil When the supply is stopped and the return is opened, the variable valve timing mechanism 2
7 oil pressure decreases, but the three-way solenoid valve 29
By branching the small oil passage 30 from the more upstream side to the supercharger 10, a sudden drop in oil pressure to the supercharger IO is avoided and lubricity during inertial rotation is ensured.

In the above embodiment, the introduction of hydraulic pressure to the variable valve timing mechanism 27 is switched on and off by the three-way slide/id valve 29, but the operation between the on state and the off state is configured in the opposite manner. Even if the key switch 41 is turned on, it is sufficient to operate the key switch 41 so as not to connect to the return side when the key switch 41 is turned on.

Further, the variable valve timing mechanism 27 having the structure shown in FIG. 2 can be formed compactly, and in addition to making the phase of the intake valve 4 variable, it can also make the phase of the exhaust valve 6 variable in response to other requirements. good. Further, the variable valve timing mechanism 27 can be modified to other hydraulically operated mechanisms as appropriate.

Next, the control operation of the engine ignition timing and fuel injection amount when switching the valve timing by the engine control unit 36 will be explained.

First, in step SI, for example, the engine speed Ne,
Input various data such as engine load R. Next, the valve timing control map shown in FIG. 4 is referred to using the read data of the engine speed Ne and the engine load R as parameters, and the corresponding region is calculated to determine which region the current operating region belongs to.

Further, the process proceeds to step S, in which the valve timing (retard or advance amount) required by the engine is calculated in accordance with the above-mentioned applicable region.

Thereafter, in step S4, the current control state is determined by determining whether or not a commanded fixed time has elapsed since the start of control for changing the valve timing from the retard state to the advance state or from the advance state to the retard state.
That is, it is determined whether or not the valve timing is currently in a transient state, and if YES, it is in a transient state, step 88 - SI! The engine ignition timing and fuel injection amount are controlled according to the viscosity of the engine oil (determined using oil temperature and oil pressure as parameters).

On the other hand, if it is not a transient state (No), step S,
-S, the ignition timing and fuel injection amount are controlled according to each map value according to the normal retard state and non-retard state (advanced).

That is, if the valve timing required by the engine is not in the retard state, that is, if it is in the advance state, the process moves to step S7 to advance the engine's ignition timing and control the fuel injection amount using the corresponding fuel map value. .

On the other hand, when the valve timing required by the engine is in the retard state, the process proceeds to step Ss, where the engine's ignition timing is retard-controlled according to the normal map value, and the fuel injection amount is controlled using the corresponding fuel map value. Take control.

On the other hand, at the time of the valve timing switching transition when the determination in step S4 is YES and the process proceeds to step S,
In step S, the hydraulic pressure P and oil 1fflTh of the hydraulic oil of the variable valve timing mechanism described above are respectively calculated, and further in step S, the response time of the valve timing switching mechanism is calculated in accordance with the calculated values P and Th. .

Then, the process further proceeds to step S10, where the elapsed time t after the actual valve timing switching is newly calculated (counted).

Furthermore, in step S, map values of ignition timing and fuel injection amount corresponding to the above calculated values are read, and step S1! Finally, the optimal ignition timing and fuel injection amount are calculated accordingly.

As a result, the engine control device with the above configuration prevents fluctuations in the engine control amount during transient valve timing switching of an engine with a variable valve timing control mechanism using hydraulic pressure, eliminates torque shock, and provides good exhaust emission performance. This makes it possible to provide a new engine.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a control system of an engine control device according to an embodiment of the present invention, FIG. 2 is a sectional view of a variable valve timing mechanism in the embodiment device, and FIG. A flowchart showing the engine control operation of the engine control unit, FIG. 4 is a control area map used in the control shown in FIG. 3, and FIG. 5 is a time chart showing the variable valve timing characteristics of the device according to the embodiment. It is. 1... 4... 8... 10... 11, 12... 13... 14... 15... 24... 26...・ 27... 29... 36... ・Engine, intake valve, intake passage, supercharger, camshaft, cam pulley, timing belt, engine output shaft, oil pump, hydraulic control means, valve timing Variable mechanism/three-way solenoid valve/engine control unit Applicant Mazda Corporation

Claims (1)

[Claims] 1. A valve timing variable means that changes the valve timing of the engine using a hydraulic actuation mechanism, and an engine control means that controls the operating state of the engine based on a predetermined control logic. In the engine, a hydraulic oil viscosity detection means for detecting the viscosity of the hydraulic oil of the hydraulic operating mechanism, and a delay time corresponding to the viscosity of the hydraulic oil detected by the hydraulic oil viscosity detection means are set, and after the delay time, the An engine control device comprising: control logic changing means for changing the control logic of the engine control means. 2. The engine control device according to claim 1, wherein the control logic of the engine control means is ignition timing control. 3. The engine control device according to claim 1, wherein the control logic of the engine control means is control of fuel supply amount.