JPS60184936A - Engine valve timing controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application] The present invention generally relates to an engine control device, and more particularly to an electrohydraulic control device for controlling the timing of intake valves and exhaust valves of an internal combustion engine. .

[Prior art]

It has long been recognized by engine manufacturers, particularly those involved in high performance engines, that controlling valve timing can achieve desired engine operating results. Inlet valve at idle, normal load range and high performance conditions.

The ideal timing for exhaust valves varies widely.

Since the valves are controlled by cams, timing must be compromised to suit a particular purpose. In production engines, valve timing is usually compromised to suit the load or speed range, but to the detriment of idle and high performance ranges. Similarly, in high performance engines, the timing can be adjusted towards the high performance range of the engine, so the valve timing in the idle range 2 normal load range is not optimal.

As early as 1903, Alechibunda Winton used a pneumatic device to adjust the lift of a valve. His intention at the time was to throttle the engine using an intake valve, as opposed to the traditional throttle plate method. Nearby, centrifugal cam slots were used that allowed valve timing to be varied as a function of engine speed rather than varying head or opening time.

Additionally, systems have been developed that completely stop valve operation in certain engine operating ranges, effectively closing one or more shillings. Engines that use this technical concept and are currently on the market include an 8-inch cab rack.
It has a 6-4 engine.

However, most of these known control devices require expensive and very high power solenoids to provide the force necessary to open and close the engine valves. Users therefore pay the penalty of high cost for such engines.

[Controlled Displacement Hydraulic Pressure 7] by Mr. Wieler
U.S. Pat. No. 3,439,661, entitled ``Hydraulic Valve Lifter'', teaches a hydraulic valve lifter. Tominaga (Tomi)
U.S. Pat. No. 4,112,884, entitled Valve Lifter for Internal Combustion Engines, et al., teaches a structure for a valve lifter. The devices disclosed in both of the above patents operate to provide some timing control to the valve. U.S. Patent No. 4,111.165 entitled "Valve Operating Mechanism for Internal Combustion Engines" by Aoyama et al.
No. 2, teaches controlling oil in a hydraulic valve lifter to drain the oil during deceleration in response to engine speed (rotational speed) and throttle opening, thereby limiting the stroke of the pulp lifter. . Yusenzawa (Ta
U.S. Pat. No. 4,258,671 entitled "Variable Lift Mechanism for Internal Combustion Engines" by M. Kizawa et al. teaches solenoid valve control of hydraulic valve lifters in overhead cam (OHC) engines. In response to engine temperature, manifold pressure, and rotational speed, the lifter oil pressure is adjusted to form the rigid link necessary to operate the engine valves. This No. 4.258.6
No. 71 study teaches the control of all 7 rings! Ru. The last two bamboo licenses listed above (@4,111.165 and No. 4,
No. 258,671) does not teach returning oil to the pulp lifter to return it to its normal starting position after each operation so as to control each engine cycle separately. Therefore, on the next engine cycle, the electronic control unit controlling the operation of the oil will not know the position of the starter. If it is necessary to delay the valve opening on the next engine vehicle, the valve opening will not change from the previous engine vehicle unless the lifter is extended again. U.S. Pat. No. 4,111,165 teaches a pump and regulator that provides hydraulic pressure to a lifter, and U.S. Pat. No. 4,258,671 teaches oil pressure provided by an oil source driven by an engine. Supply lines are taught. Without further action, normal engine oil pressure is insufficient to lower or return the lid to its highest position in the time available between engine cycles. Both of the above systems could be used by adding a boost pump with an appropriate pressure capacity, but this would be expensive and would add unnecessary load to the engine.

Moreover, the purpose and effect obtained by controlling the engine valves are thereby lost.

〔overview〕

To solve the above problems, an engine valve timing control system is disclosed herein that utilizes a source of engine oil to operate a hydraulic pulp lifter. By controlling the fluid pressure generated in the oil source as a result of lifter operation, several pulses of fluid at considerably high pressure are delivered to the lifter to return or re-extend the lifter to its normal position during the engine cycle. encourage people to do what they do. This device is
A microprocessor-based control system in which several engine sensors sense engine conditions and the microprocessor responsive to the sensed engine conditions addresses a memory containing an engine condition to valve opening time map. A signal from the memory is provided to a specific timer device for a given cylinder. A timer device operating in conjunction with the known position of the cylinder piston operates a solenoid valve that directs and maintains a predetermined amount of oil within the associated hydraulic lifter.

These and other advantages will become apparent from the following detailed description and drawings.

〔Example〕

The engine valve timing control system shown in the figures uses a microprocessor-based controller to control the opening timing and duration of one or more intake and exhaust valves of an internal combustion engine.

FIG. 1 is a schematic diagram showing the configuration of a control device.

Several engine operating conditions are sensed by one or more sensors 1o, such as an exhaust gas sensor. The above exhaust gas sensor is usually oxygen gas sensor +j12
shows the combustion characteristics of the engine. A temperature sensor 14.16 provides a signal to the control unit indicating engine temperature, air temperature. Other sensors indicate the bass throttle position fi18 and can be used to determine the amount of fuel required in the engine manifold. However, this control device
If it is a fuel injector, the air flow rate must be calculated by several sensed variables of the engine and the empirically determined volumetric efficiency. In the illustrated valve timing control system, it is convenient to measure the air intake into the system, and therefore a mass airflow meter can be placed at the air intake of the engine. By directly measuring the air flow rate, there is no need to memorize an empirically determined volumetric efficiency map to determine the air flow rate. Changing the valve timing changes the volumetric efficiency accordingly, complicating any airflow calculations. Therefore, direct measurement of air content is desirable.

The signals of these sensors, which produce analog signals, are processed in an analog-to-digital converter 22 to convert the sensor signals to equivalent digital signals for use in a microprocessor 24. Other key points to the microprocessor are the engine start 26 and the end positions 27 and 28 of the aperture blades of the throttle body. Microprocessor 24 receives a number of signals indicative of engine conditions and generates a number of engine control signals according to control laws stored in its memory. This microprocessor 24
is, for example, the Motorola 68701. , the control device of the present invention relates to the control of engine valves, and is, for example, a programmable ROM (FROM).
It has a memory device 3o like this. This memory device contains a memory map of engine events for a particular engine associated with various valve opening positions. In order to adapt the controller to a group of engines, each engine belonging to the engine group has its own unique FROM 30 that is plugged into its controller.

The microprocessor will control the FR as a result of engine conditions.
OM 30 is addressed to determine unique valve opening and closing times and durations for each cylinder. FROM
30 is, for example, a Motorola 2716.

An electronic control unit (ECU) 32 is synchronized with the engine by a timing device 34 coupled to the engine camshaft. Timing device 34 generates a signal indicative of the known position of the piston of each seven ring, such as top dead center (TDC)-i of the compression stroke or bottom dead center (BDC) of the working stroke. The camshaft is coupled to the engine crankshaft,
It rotates at half the speed of the crankshaft, ie only once for each engine vehicle. The engine crankshaft provides power and drives a hydraulic pump 64 that pumps engine oil through the engine. This oil is used in the valve lifter or regulator of the control device of the invention.

Signals 35 from timing device 34 are provided to a phase-locked loop timing circuit 36 where the frequency of each input signal 35 is multiplied by a factor of ten to obtain fine timing. Phaseron loop timing circuit 36
The output signal 38 or fine timing signal 38 is fed to several programmable timing devices 40, one for each cylinder.

The fine timing signal 38 causes the timing device 40 to
The valves are arranged at predetermined timing positions to initiate valve operation in each cylinder. Additional timing device 42
is provided, the timing device 42 being responsive to the known piston position of a given cylinder, % to the piston position of the first cylinder. This timing device 42 determines the relative positions of the pistons of the remaining cylinders.

Programmable timing device 40 is, for example, a Motorola 6840 unit.

Predetermined signals from each timing device 40 are provided to microprocessor 24 for generating control signals to solenoid control valves 44-50. Valves 44-50 control the outflow of oil from hydraulic valve lifters 51-58 for controlling engine valve timing in a manner described below in response to these control signals.

FIG. 2 will be explained. The diagram schematically shows a hydraulic circuit for an engine valve timing control device. For purposes of explanation, this control system will be described with respect to a four cylinder internal combustion spark ignition engine. The specific firing order of the engine ignition system is 1-
It is 2-4-3.

FIG. 2 shows a grouping of engine valves whose camshafts are 180 degrees apart. In particular, the intake valves of cylinder 1 and cylinder 4 are grouped and controlled by a first solenoid valve 44 . Similarly, the exhaust valve 1 and the exhaust valve 4 are controlled by the second solenoid valve 46, the intake valve 2 and the intake valve 3 are controlled by the third solenoid valve 48, and the fourth solenoid valve 50 is controlled. The exhaust valves 2 and 3 can be grouped. Thus, in Figure 2, 4
Four solenoid valves 44-50 control the four cylinders.

The oil supply line that flows into the engine block is an engine oil supply line 6 between several valve lifters 51 to 58.
0 and a return line 66 are formed. The engine oil pump 64 supplies engine oil to the system. The check valve 66 allows the oil to be replenished into the hydraulic system only by the amount of oil lost by leakage in the vicinity of the valve lifter slide-on rule.

Another check valve 67,69 is arranged in each of the supply line 60 and return line 62 for each pulp lifter 51-58. ECU shown in complete form in Figure 1
32 controls each solenoid valve 44-50. In this control system, solenoid valves 44-50 operate to close return line 62, maintain oil in the lifter, and open engine valves.

FIG. 5 will be explained. The figure shows a control device for one engine valve in an open cam device,
A solenoid control valve 44 for draining oil, an engine valve lifter 51, a cam follower 68, an overhead cam 70, an engine valve spring 72, and an engine valve 74 are shown. Also shown are a supply line 60 for supplying oil to the lifter, and a return line or lifter oil withdrawal line 62 for removing oil from the lifter.

Overhead cam 70 has a base circle 76 from which projections 78 extend at specific circumferential locations.

When the cam follower 68 moves on the cam surface, the engine valve 74 opens or closes on the rising and falling surface of the protrusion 7B. This is conventional valve operation and will not be further described here.

In an overhead cam system, the present invention uses height movement of the knob lifter piston 80 to control the pivot point of the cam follower 68.

The piston 80 of the pulp lifter 51 is connected to its housing 82.
As the cam follower 68 becomes more extended, the cam follower 68 operates on the cam profile to open the valve earlier and close it later. Early valve opening operations and large valve opening operations that take a relatively long time are
It can be used during high speed engine operation or high loads where it is desired to inject a large amount of fuel. When the lifter piston 80 is retracted into the housing 82 of the pulp lifter 51, the cam follower 68 is driven downwardly onto the beam lid 51 according to the contour of the cam 70. When fixed over the entire length of the lifter 51, the contour of the cam 70 drives the engine valve 74 from above, against the valve spring 74, the cam follower 68 downwardly to open the pulp 74.

In idle conditions, slow engine valve opening action is desired. In this case, the amount of valve opening will be smaller and the valve will close faster than before. This reduces the amount of fuel injected and improves engine emissions at idle speed. The short duration of engine valve opening at idle also eliminates valve overlap, thereby reducing contamination of freshly drawn fuel with exhaust residue. Valve overlap poses little problem in combustibility at high speeds and high loads where the valve overlap time is short.

And the manifold pressure differential across the engine is reduced due to reduced contamination. However, at high speeds and high loads, valve overlap improves blower and economy.

The supply of oil to the hydraulic lifter 51 is controlled to move the lifter piston 80 into and out of its housing. When the correct activation time is reached, the solenoid control valve 44 closes, sealing the return line 62 and retaining oil in the hydraulic lifter 51.

This constitutes a rigid oil link and keeps the oil lifter 80 stationary. Next, the cam follower 68
An operating force of 0 causes it to swing on the lifter piston and actuate the valve 74.

The pulp lifter 51 shown in the exploded view of FIG. 4 is used in this invention. The illustrated pulp lifter includes a lifter body 82, which includes a return spring 8.
4. Non-return square holder 86, non-return ball valve 88 and spring 9
0, a check valve piston 92, a lifter piston 80, and a piston holder 94. Return spring 84 acts to return lifter piston 80 to its extended position. The force of the return spring 84 plus the pressure from the oil supply line 60 shown in FIG. 7 cooperates to return the piston 80. Check ball valve 88,
The ball spring 90 and the valve holder 86 are connected to the check piston 92
It operates to retain oil within the oil tank and allow it to flow out from the oil cap to the return line 62.

As shown in FIG. 3, oil supply line 60 enters the pulp lifter at the top of lifter body 82 and exits through an orifice 96 at the bottom of lifter body 82. The flow of oil thus enters the cavity in which the return spring 84 is located through the check valve 88 and exits from the bottom of the lifter through the orifice 96.

FIG. 6 shows an example of application of the present invention to a push rod structure. The cam 98 is under the piston, and the push rod 100 is attached to the cam 98.
and the swinging arm 102 to open and close the engine valve 104. The operation of the cam, pushrod, rocker arm, and valve assembly is well known and will not be described here. An electromagnetically controlled hydraulic valve lifter 106 is disposed between the cam 98 and the rocker arm 102 in alignment with the push rod 100. The operation of this controller is similar to that previously described in that a hydraulic link is formed between the ends of pistons 108, 109 in lifter 106 under control of solenoid valve 110. Therefore, when solenoid control valve 110 is not energized, oil flows from oil supply line 60 through check valve 67 and hydraulic lifter. When the lower piston 109 is raised by the surface of the cam 98, it is pushed out from the oil filler lid into the oil discharge path 62. However, once the solenoid valve is energized, the drain passage is closed and the oil between the pistons 108 and 109 directs the movement of the lower piston 109 to the piston 10B.
The push rod 100 acts on the rocker arm 102 in the normal manner to open the valve. Thus, similarly to the device shown in FIG. 5, in this Takeari device as well, the opening/closing timing of the engine valve 104 is controlled by forming a rigid link.

FIG. 7 is a timing diagram of a device according to the invention.

That is, the top line 112 shows the closure of the solenoid control valve 110, the middle line 114 shows the pressure pulse in lines 60, 62, and the bottom line 116 shows the engine valve travel. The center line representing the pressure pulse for the hydraulic system will be discussed. The first pulse 118 is the pulse that occurs when the cam follower 68 contacts the cam 70 to force the lifter piston 80 down to remove oil from the lifter.

The second pulse 120 is the pulse generated by the solenoid valve closing and closing, forming a rigid oil link, and cam pressure being suddenly applied to that link via the cam follower. The third pulse 122 is believed to be an echo in the oil line as a result of reflection from inside the hydraulic line.

motion Next, the operation of the apparatus of this invention will be explained.

In FIGS. 1, 2, and 5, check valves 67, 69, 69a in the supply and return passages prevent oil from flowing in any direction other than the direction in which the designer desires the oil to flow. This device is primarily concerned with controlling the opening timing of engine valves, thereby controlling not only the length of time that the valve is open, but also the lift of the valve itself, depending on the shape of the cam. As previously mentioned, the ECU 32 determines the ideal time for the engine valves to open under actual engine operating conditions.

This is done by timing device 40.42. The first timing device 42 is an absolute timing device that indicates the time from a predetermined engine event, such as top dead center of the engine piston of the compression stroke of the first cylinder. 1st
Sensor 124, which couples timing device 34 to phaseron loop logic 36 as shown, includes:
A specific signal is generated indicating the engine piston position at top dead center of the first cylinder and all other known positions of the device. By suitably designing the timing device 34, it is possible to indicate the top dead center position of each of all engine pistons, and by further devising the timing device, the top dead center position of the first cylinder can be indicated in particular. A signal can be generated so as to be identified.

In a map of engine events placed in FROM 30 for a given engine condition, the time of intake engine valve opening for a particular cylinder is stored as the time from the known 7-ring top dead center or event. . This time value is placed in the timing device 40, and the phaseron loop's fine timing signal 38 acts to cause the timing device 40 for a particular cylinder to count down to a predetermined number. An output signal 126 is generated indicating the time at which the valve is to be activated (in this system, the solenoid control valves 44-50 are to be closed). These output signals are
Processed with Microprocene v24 and stopped working lFi
is sent to a fixed solenoid control valve.

The above device shows a method of controlling the opening timing of the intake valve or exhaust valve of a given cylinder. To control the actual closing of the engine valve 74 on the descending side of the cam projection 78,
A powerful solenoid is required. The forces on the lifter and the forces transmitted through the oil to the plunger of the solenoid control valve 44 are very strong and make the plunger very difficult to move. However, the closing timing of the engine valve 74 is a direct function of the opening timing.
The closer the opening time is to the top of the cam protrusion 7B, the closer the closing time is to the top of the cam protrusion 7B on the opposite side of the cam.

As mentioned with reference to FIG. 7, the generated pressure pulse 1
18,120.122 are provided via the fluid system.

These pulses act to force more oil into the lifters 51-58, returning the lifter piston 80 to its standard position. However, in a lifter where control is currently provided by projection 78 of cam 70, when a pressure pulse is applied to lifter piston 80, the piston does not move as cam TO begins to move valve stem 74.

When the valve opening side slope of the cam begins to move the cam follower 68, the lifter piston 80 begins to descend due to the opened electromagnetic valve 44. When oil flows out of the lifter 51, the lifter supply check valve 88 closes. by this,
The return check valve 69 is opened for oil flowing out of the lifter, and the oil is allowed to flow through the open solenoid valve 44. The return/return check valve 69a of the lifter 57 pair in the same solenoid valve 44 is closed by this flow to prevent uncontrolled flow back to the other lifters of the pair. Thus, the solenoid valve 44 completely controls the outflow of oil from the lifter 51.

Oil flow from solenoid valve 44 is then directed to the inactive lifters and returns them to their fully extended position. The lowered position of lifter 51 continues until ECU 32 determines that it is the correct time to begin opening engine valve 74. ECU 32 then generates an electrical signal to close solenoid valve 44, stopping oil flow from lifter 51 and creating a rigid hydraulic link within the lifter body. At this point, the force to compress the hydraulic fluid in lifter 51 is exerted by valve spring 7
much greater than the force required to compress 2. Therefore,
The movement of the cam opens the engine rather than lowering the lifter.

Cam follower 68 and valve 74 are defined by the profile of cam 70, but follow the remainder of the cam profile giving the valve reduced movement by the amount initially in the lifter down position. When the cam 70 closes the valve 74, the cam follower 68 is released from contact with the cam 70 because the engine valve 74 is seated.
Also, the cam profile continues to slope toward the base circle. At this point, the solenoid valve 44 remains closed, and the other lid 5
The cam follower 68 remains in contact with the cam base circle 76 as the hydraulic pulse from 2-58 enters through the supply check valve 67 and, along with the force of the stopper return spring 84, pushes up the lifter piston 80. The lifter is brought back to full extension,
At some point when the cam follower 68 is again in contact with the cam base circle 76, the solenoid valve 44 can be opened again to end the cycle and prepare for the next vehicle. At this point, by opening the previous VCt solenoid valve, the pressure pulse from the other cylinder is passed through the lifter and the supply check valve 6.
7 and would be able to pass through the open 9'' solenoid valve without any action to return the piston.

The force of the valve spring 72 and the generated cam force exerted on the valves 74, 104 by the cam 7 followers 68, 102 are very strong and therefore the cam follower takes the path of least resistance when positioned for opening and closing the valve. Please be careful.

This path of least resistance is through a piston on the lifter that opposes the oil pressure of the hydraulic system, and the cam follower forces oil out of the lifter until the solenoid valve closes.

The performance advantages of the device according to the invention are that it allows the engine to produce more power for a given engine size, is more fuel efficient for very large engines, and has reduced valve bulk which reduces dilution at idle. This means that there are few Also, by controlling the intake and exhaust valves, hydrocarbons and exhaust gases are better controlled. The amount of fuel that enters the Schilling during deceleration operations is small, which improves emissions and fuel economy over several speed ranges.

It is a significant advantage of the device of the invention that the pressure pulses 118-122 from the descending lid are used to return the piston of the inactive lifter to the cam base circle.

By doing so, the starting position of each valve opening timing can be identified and repeated. Additionally, by moving the lifter piston back so that the cam follower was pressed against the cam base circle, the wear on the cam caused by impacting the follower was reduced as well as the noise associated with the impact.

In order to improve the lifter response in the device, it is essential that the oil be delivered in a pulsating manner, that it flows quickly through the lifter, and that the oil supply is unrestricted so that it does not run out. In order to use such high pressures on the device due to the pressure pulses generated in the awn, a suitable oil ring 1
Note that 28 may be advantageously placed around the lifter as shown in FIG.

The interior of the lifter 51 must be such that the lifter piston 80 can be compressed without blocking the return spring. This stiffness is a design feature that prevents the lifter piston from returning so close to the bottom that it entangles the spring coil as it tries to return.

Although I have described a device mainly based on a single-function microprocessor that controls multiple engine valves,
Such a control device can be combined with an ignition device and a fuel injection device into one integrated device. This is true, as long as both the ignition system and the fuel injection system require a large number of similar input signals and have as much processing power as the subject device.
It is easy to scale.

Using a microprocessor-based controller, pressure pulses generated by cam movement in a closed-loop hydraulic oil system create high pressure pulses in the fluid line that return the pulp lifter to the cam's baseline position. An engine valve timing control system has been described that operates in such a manner.

The device has individual timing for each cylinder,
It shows how each cylinder can be controlled individually so that it is not dependent or a function of the timing of the previous or next cylinder, nor is it a function of its own previous vehicle.

Various parameters are chosen by design, such as those that provide an absolute timer with a signal indicating the known position of a known cylinder, which may be just one cylinder in the entire engine or may be seven rings each. It is something that will be done.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a control device of the present invention. FIG. 2 is a schematic diagram of the hydraulic system of the present invention. FIG. 3 is a sectional view of the pulp lifter. FIG. 4 is an exploded view of the pulp lifter of FIG. 3. FIG. 5 is a sectional view of the overhead cam valve device. FIG. 6 is a sectional view of the push rod valve device. FIG. 7 is a timing diagram. 44...Solenoid control valve, 60...Fluid supply pipe line,
62...Fluid return pipe, 67.69°69a...
・Check valve, 26, 27, 28, 134...Sensor, 32...Electronic control unit, 68...Cam 7 orer, 70...Cam, 76...Cam foundation Circle, 78...Cam protrusion, 51...Pulp lifter,
64... Working fluid source. Patent Applicant Allied Corporation Agent Masaki Yamakawa (I9) F6

Claims (1)

[Claims] (1) In order to individually control the operating timing of at least two cylinder valves in an internal combustion engine, a cam having a cam base circle (76) and a timing protrusion (78) is provided for each valve, and each cam (70) and a cam (70) having a cam operable to open and close each cylinder valve according to a predetermined time sequence by a cam follower (68) connected between each valve (74); and a source of actuating fluid (64); Hydraulic valve lifter (51) for each cylinder and cam follower (68)
) and a valve lifter operable to couple a valve (74) to a valve (74), the engine valve timing control having an input port, an output port connected to the valve lifter, and having an input port and an output port that are normally open and pass through the valve lifter. an electromagnetic control valve for allowing flow of a working fluid; a fluid supply line (60) connecting said lifter to an output port of said control valve and said working fluid source (64); each said lifter and said control associated therewith; a fluid return conduit (62) connected between the input port of the valve; and: disposed in the fluid supply conduit and the fluid return conduit;
check valves (67, 69, 69a) for controlling fluid flow through the control valve (44) in one direction; and a plurality of sensors for generating signals in response to engine operating conditions. (2
6, 27, 28, 134); an electronic control unit (32) having a microprocessor and generating a control signal according to the engine control law stored in the microprocessor and the sensor signal; ), the control signal actuates the control valve to prevent fluid flow through the control valve, forms a hydraulic link to the lifter, and connects the cam follower coupled to the lifter to the control valve. An engine valve timing control device, characterized in that it is completely equipped with an electronic control unit adapted to actuate a cylinder valve. 2. The apparatus of claim 1, wherein the apparatus is responsive to fluid pressure pulses generated when one of the control valves is actuated and transmits the pulses to each of the other control valves with the control valve closed. Apparatus, characterized in that it feeds into a lifter, thereby returning said lifter to a cam base circle.