JPH01305112A - Valves system device for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure adequate valve switching operation all the time by installing a pressure control valve for controlling charge/discharge of oil pressure to an actuator between a pressure source and a hydraulic actuator which makes switching drive of an intake/exhaust valve, and making switching operation of this valve adjustable according to the characteristic state of oil. CONSTITUTION:The switching valves 11, 21 of an intake/exhaust valve, etc., are so arranged as to be opened/closed by actuators 12, 22 driven by means of oil pressure supplied from a pressure source 116 and pressure source 116 and the actuators 12, 22. Supply of oil pressure to the actuators 12, 22 from the pressure control valves 111, 112 and release of oil pressure from the actuator 12, 22 are controlled by these pressure control valves 111, 112. Still in this case, a viscosity detecting means A for detecting, for instance, viscosity, among properties of work oil supplied from the pressure source 116 is installed and its output signals are outputted to a switching operation adjusting means B. Then, the pressure control valves 111, 112 are controlled according to the viscosity of the work oil so as to have the switching operation of switching valves 12, 21 requlated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for hydraulically driving open/close valves such as intake and exhaust valves of an internal combustion engine.

[Conventional technology]

2. Description of the Related Art Conventionally, a system is known in which intake and exhaust valves are driven to open and close by a hydraulic actuator, and the timing and duration of supply of hydraulic pressure to the actuator are controlled to obtain arbitrary opening and closing operations of the intake and exhaust valves.

JP-A-58-82010 discloses a configuration for controlling the opening of a servo valve that constitutes an actuator according to the operating state of the engine, and JP-A-58-152140 discloses a configuration that controls the opening degree of a servo valve that constitutes an actuator according to the operating state of the engine. A configuration is shown in which the actuator is controlled accordingly and the opening timing of the exhaust valve is controlled.

[Problem to be solved by the invention]

However, the conventional valve drive device having the above configuration does not take into consideration the case where the properties of the hydraulic oil for driving the opening and closing of the intake and exhaust valves change due to engine temperature changes, etc. There is a risk that the accuracy of operation will decrease. In other words, for example, if the viscosity of the hydraulic oil changes and the flow characteristics change, the operation of the actuator will change and the intake and exhaust valves will no longer perform the intended opening and closing operations with high precision, resulting in a decrease in engine performance and damage to the intake and exhaust valves. There is a risk that abnormal behavior will be induced and noise will be generated. In addition, when the proportion of air bubbles contained in the hydraulic oil changes depending on the operating condition of the engine, the bulk modulus of the hydraulic oil changes, which changes the pressure increase characteristics of the hydraulic oil and changes the operation of the actuator.
A similar problem arises.

SUMMARY OF THE INVENTION An object of the present invention is to provide a valve driving device that allows an on-off valve to always perform a desired opening/closing operation even if the properties of hydraulic oil change.

[Means to solve the problem]

As shown in the configuration diagram of the invention in FIG. 1, the valve drive device according to the present invention is provided with a pressure source 116, an actuator 12.22 that drives the on-off valve to open and close, and between the pressure source and the actuator, according to pressure control valves 111, 112 for controlling the supply of hydraulic pressure from the pressure source to the actuator and the release of this hydraulic pressure from the actuator, and means A for detecting the properties of the hydraulic oil supplied from the pressure source. ,
It is characterized by comprising means B for controlling the opening/closing operation of the pressure control valve and adjusting the opening/closing operation of the opening/closing valve.

[For production]

When the properties of the hydraulic oil change and the flow rate characteristics or pressure change characteristics of the hydraulic oil supplied to the actuator change, the opening/closing operation of the pressure control valve is controlled to adjust the supply state of the hydraulic oil to the actuator. The desired opening/closing operation can be obtained.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

FIG. 2 shows an embodiment of the invention. In this figure, the structures of the intake valves 11, 21 and surrounding members supporting them have conventionally known configurations and are shown in a simplified manner. In this example, the cylinder head is made from an aluminum alloy and the intake valves 11.21 from steel.

The intake valves 11.21 are driven by hydraulic actuators 12.22 and are each biased in the open direction by springs 15.25. The hydraulic actuator 12, 22 comprises a plunger 13.23 and a hydraulic chamber 14.24.

The hydraulic chambers 14.24 are connected to the hydraulic pressure control valve 111 via piping 101, 102, and the piping 101.
It is connected via 103 to a pressure control valve 112 for hydraulic discharge. Electric actuator 11 as piezoelectric element laminate
3 opens and closes a pressure control valve 111 for introducing hydraulic pressure, and an electric actuator 114 as a piezoelectric element stack opens and closes a pressure control valve 112 for discharging hydraulic pressure. High pressure accumulator 115 is connected to hydraulic pump 116 via piping 104. A pressure regulating valve 117 controls the control hydraulic pressure to the hydraulic actuator 14.24. The low pressure accumulator 118 is connected to the oil tank 10 via the piping 105.
Connected to 6.

107 is a strainer.

The control circuit 130 controls the operation of the intake valves 11, 21 by controlling the piezoelectric actuators 113, 114, and is configured as, for example, a microcomputer system. The control circuit 130 includes a microprocessing unit (MPU) 131 and a memory 13.
2, a human power port 133, an output boat 134, and a bus 135 that interconnects these components.

Various sensors are connected to the input port 133, and engine operating condition signals are input thereto. Crank angle sensor 141
generates a pulse signal every 720° CA (ie, every engine cycle) and serves as a reference signal.

The crank angle sensor 142 generates a pulse signal every 30° CA, so that the engine speed can be determined.

The throttle sensor 143 detects the throttle valve opening (or accelerator pedal opening) of the internal combustion engine. The hydraulic oil temperature sensor 144 is provided in the pipe 101 and detects the temperature of the hydraulic oil. Hydraulic oil viscosity sensor 145 and air bubble ratio sensor 1
47 is attached to the pipe 101, for example, and detects the viscosity of the hydraulic oil and the proportion of air bubbles in the hydraulic oil, respectively, as will be described later. The cooling water temperature sensor 146 is provided in the water jacket of the engine body and detects the cooling water temperature. Throttle sensor 143, hydraulic oil temperature sensor 144, hydraulic oil viscosity sensor 1
45, cooling water temperature sensor 146, and bubble ratio sensor 1
The detection signal No. 47 is input to an AD converter 148 and subjected to AD conversion.

As the hydraulic oil viscosity sensor 145, for example, a magnetostrictive vibrational viscometer, an electromagnetic vibrational viscometer, a rotational viscometer, or a capillary viscometer can be used. A magnetostrictive vibratory viscometer applies an electric pulse with a period longer than the natural frequency to a vibrating piece made of a magnetostrictive material, and detects viscosity from the subsequent attenuation of the amplitude. An electromagnetic vibration viscometer detects viscosity by comparing the amplitude of vibration of an electrostrictive element in hydraulic oil and in air. The rotational viscometer detects viscosity from the viscous torque applied to the rotor in the hydraulic oil, and the capillary viscometer detects the viscosity by measuring the differential pressure at the entrance and exit of the bypass pipe connected to piping 101. On the other hand, in the air bubble ratio sensor 147, a part of the piping is formed of a transparent material such as quartz, and the light emitted from the light emitting element is passed through the transparent piping part and received by the light receiving element, and the amount of light received at that time is Detect the bubble ratio by

The output boat 131 is connected via drive circuits 136 and 137 to piezoelectric actuators 113 and 114 for hydraulic pressure introduction control and hydraulic discharge control. In the memory 132,
A program for achieving the operation of the control circuit 130 described below is stored.

FIG. 3 shows a first embodiment of a routine for controlling the opening/closing timing of the intake valve IL21. This control routine is interrupted at every predetermined crank angle.

In step 201, the opening/closing timing and lift amount of the intake valve are determined according to the operating state of the engine, and the opening/closing timing of the pressure control valves 111 and 112 is determined so as to obtain the opening/closing operation of the intake valve. In step 202, the hydraulic oil temperature is read from the hydraulic oil temperature sensor 144. In step 203, the viscosity of the hydraulic oil is estimated from the hydraulic oil temperature based on a map or calculation formula.

When the viscosity of the hydraulic oil increases, the pressure control valves 111 and 112
The resistance of the hydraulic oil increases. As a result, in the intake valves 11, 21, the valve opening operation is delayed, the maximum lift amount is reduced, and the valve closing timing is delayed, which may reduce engine performance. Conversely, when the viscosity of the hydraulic oil decreases, the resistance of the hydraulic oil at the pressure control valves 111 and 112 decreases, the opening and closing speed of the intake valves 11 and 21 increases, and the impact on each member of the valve train increases. Noise increases. In step 204, correction coefficients for the opening and closing timings of the pressure control valves 111 and 112 are determined so that the intake valves 11 and 21 open and close as expected regardless of the viscosity of the hydraulic oil. In other words, as the viscosity of the hydraulic oil increases, the correction coefficient increases, and the opening period of the pressure control valves 111 and 112 becomes longer, thereby preventing the supply of hydraulic oil to the actuator 14, 24 and the release operation from deteriorating. 11.2
The desired opening/closing operation of No. 1 is ensured. Also, as the viscosity of the hydraulic oil decreases, the correction coefficient decreases, and the pressure control valve 11
The opening period of intake valves 11 and 21 becomes shorter.
This prevents the opening/closing speed from becoming excessive.

In step 205, the valve opening period is calculated using the correction coefficient obtained in step 204, and the drive circuit 136,
137 to the timer. drive circuit 136,
137 is the pressure control valve 11 for the time set in the timer.
1, 112 is opened.

FIG. 4 shows a second embodiment of the control routine. In the first embodiment, the hydraulic oil temperature was read in step 202, but in the second embodiment, the sensor 1 was read in step 212.
The viscosity of the hydraulic oil is read from 45. Therefore, there is no need for the process of estimating the viscosity of the hydraulic oil as in step 203 of the first embodiment, and step 212 is directly followed by step 2.
04, a correction coefficient for the opening/closing timing of the pressure control valves 111 and 112 is determined. Other processing is the same as in the first embodiment.

FIG. 5 shows a third embodiment of the control routine. In the first embodiment, the hydraulic oil temperature was read in step 202 and the viscosity of the hydraulic oil was estimated based on the oil temperature in step 203, whereas in the third embodiment, the hydraulic oil temperature was read in step 202.
In Step 2, the cooling water temperature is read from the sensor 146, and in Step 223, the viscosity of the hydraulic oil is estimated based on the cooling water temperature using a map or a calculation formula. Other processing is the same as in the first embodiment.

According to the first to third embodiments, the opening/closing timing of the pressure control valves 111, 112 is controlled according to the viscosity of the hydraulic oil, and the intake valves 11, 21 always perform the intended opening/closing operation. It becomes like this. Therefore, deterioration of engine performance is prevented, noise generation due to collision of each member of the intake valve is prevented, and durability of each member is improved.

FIG. 6 shows a fourth embodiment of the control routine. In this fourth embodiment, the opening/closing timing of the pressure control valves 111, 112 is changed depending on the proportion of air bubbles contained in the hydraulic oil, thereby ensuring the accuracy of the opening/closing operations of the intake valves 11.21. To explain in comparison with the first embodiment, steps 202 and 2
03 and 204 correspond to steps 233 and 234, respectively. In step 232, the engine speed is read from the sensor 142, and in step 233, the bubble ratio in the hydraulic oil is estimated based on the engine speed using a map or a calculation formula. .

Here, it is estimated that the higher the engine speed, that is, the greater the number of operating cycles of the valve train, the higher the proportion of bubbles in the hydraulic oil. When this bubble ratio changes, the bulk modulus of the hydraulic oil changes and the pressure increase characteristics of the hydraulic oil change.
The opening and closing operations of the intake valves 11.21 become different from the expected ones. In step 234, a correction coefficient is set to be large so as to lengthen the opening period of the pressure control valves 111 and 112 as the bubble ratio increases.In other words, as the air bubble ratio increases, the amount of hydraulic oil supplied to the actuators 12 and 22 is increased to increase the intake air. The desired opening and closing operations of the valves 11 and 21 are ensured. Other processing is the same as in the first embodiment.

FIG. 7 shows a fifth embodiment of the control routine. In the fourth embodiment, the engine speed is read in step 232, but in the fifth embodiment, the bubble ratio in the hydraulic oil is directly read from the sensor 147 in step 242.

Therefore, there is no need to perform the process of estimating the bubble ratio as in step 233 of the fourth embodiment, and the process proceeds directly from step 232 to step 234.
A correction coefficient for the opening/closing timing is determined. Other processing is the same as in the fourth embodiment.

According to the fourth and fifth embodiments, the opening and closing timings of the pressure control valves 111 and 112 are controlled according to the proportion of air bubbles in the hydraulic oil, so that the intake valves 11 and 21 always perform the intended opening and closing operations. Therefore, deterioration in engine performance is prevented, noise generation due to collision of each member of the intake valve is prevented, and durability of each member is improved.

In addition, the first to fifth embodiments achieve the intended opening and closing operations of the intake valves 11.21 without increasing the number of parts, and the cost, the dimensions and weight of the entire device, and the arrangement of each member are reduced. It is advantageous in this respect.

In each of the above embodiments, the opening/closing timing of the intake valve is controlled, but the opening/closing timing of the exhaust valve may be similarly controlled.

〔Effect of the invention〕

As described above, according to the present invention, even if the properties of the hydraulic oil change due to changes in the operating conditions of the engine, the opening/closing valve always performs the intended opening/closing operation, thereby preventing a decline in engine performance. Also, the generation of noise from the valve train is prevented.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the invention; Fig. 2 is a schematic block diagram of a hydraulic system and an electronic control system in an embodiment of the invention; Fig. 3 is a flowchart of a control routine of the first embodiment; FIG. 5 is a flowchart of the control routine of the third embodiment; FIG. 6 is a flowchart of the control routine of the fourth embodiment; FIG. 7 is a flowchart of the control routine of the fifth embodiment.
□It is a yard. 11.21... Intake valve (on/off valve), 12.22... Actuator, 111.112... Pressure control valve, 116... Hydraulic pump (pressure source), 130... Control circuit. Fig. 1 Fig. 2 1121... Intake valve 111, 112 ・
・Pressure control valve 12.22...actuator
１１６・；゛ Hydraulic bong Fig. 3 Fig. 5 Fig. 6

Claims (1)

[Claims] 1. A device for opening and closing an on-off valve of an internal combustion engine, which includes a pressure source, an actuator for opening and closing the on-off valve, and
A pressure control valve is provided between the pressure source and the actuator, and controls the supply of hydraulic pressure from the pressure source to the actuator and the release of the hydraulic pressure from the actuator, and controls the properties of the hydraulic oil supplied from the pressure source. a means for detecting;
A valve drive device for an internal combustion engine, comprising means for controlling the opening and closing operations of the pressure control valve according to the properties of the hydraulic fluid, and adjusting the opening and closing operations of the opening and closing valve.