JPS58152140A - Opening time control device for oil pressure pipe contolling exhaust valve - Google Patents

Abstract

PURPOSE:To make it possible to control automatically the time of opening the oil pressure pipe controlling exhaust valve of a diesel engine so that the valve is opened quickly at an optimum time in accordance with the operation conditions of the engine by a method wherein various kinds of sensors are provided. CONSTITUTION:A digital operation processor 45 adopted to control the opening time of the oil pressure pipe controlling exhaust valve transmits signals from various kinds of sensors for detecting the operation conditions of the engine. The sensors are an engine r.p.m. sensor 37, a cylinder internal pressure sensor 38, a scavenging pressure sensor 39, a fuel flow rate sensor 40, a exhaust valve lift sensor 46 and an actuator rack-bar position sensor 44. Then the operation processor 30 operates a target value of the internal pressure of the engine cylinder at the time when a scavenging port is opened under each of the operation conditions of the engine and generates a signal to a motor control circuit 43 on the base of the target value operated by the processor 30 so that a motor 42 and a valve opening time changing actuator 41 are operated and the opening time of the exhaust valve is adjusted to thereby control the engine cylinder internal pressure to a predetermined value. Further, it is also possible to diagnose and display the suitability of the adjusted valve opening time as occasion demands.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a hydraulic system that automatically controls the opening timing of a hydraulically controlled exhaust valve in a diesel engine at an optimal timing according to changes in operating conditions such as fuel properties and load conditions. The present invention relates to a control device for controlling the opening timing of a controlled exhaust valve.

In diesel engines, it is often necessary to change the opening timing of a hydraulically controlled exhaust valve in response to changes in operating conditions such as the properties of the fuel used or load conditions. for example,
In the case of partial load operation, it is necessary to delay the opening timing of the hydraulic control exhaust valve in order to reduce the decrease in thermal efficiency. That is, in the case of partial load operation, it is necessary to delay the opening timing of the hydraulically controlled exhaust valve in order to lengthen the expansion period of the combustion gas and reduce energy loss to the exhaust gas.

Therefore, in the past, a structure as shown in Fig. 1 was used.
A valve opening timing adjustment device that can adjust the opening timing of a hydraulic control exhaust valve to a desired timing has been proposed by the same applicant as the present application. That is, a branch is provided in the hydraulic path connecting the hydraulic cylinder 1 for opening the valve and the hydraulic actuator 2 that is the drive source thereof, and this branch is connected to the cylinder head of the sub-cylinder 3, and the piston 4 in the sub-cylinder 3 is connected to the hydraulic path. A spring 5 is applied toward the cylinder head, and a stopper screw 6 is arranged at the rear of the piston 4, and the position of the stopper screw 6 is changed in the left-right direction in the figure by an adjustment lever 7 using a rack and pinion mechanism. This is what I did.

According to this device, when the piston 8 of the actuator 2 enters the compression stroke according to the movement of the cam 9, the cylinder chamber 10
As the pressure of the oil inside begins to rise, the piston 4 receives the pressure and moves to the right in the figure while pressing the spring 5 until it hits the stopper screw 6. From this state, when the oil pressure by the piston 8 of the actuator 2 further increases and overcomes the pressure of the exhaust valve spring 11, the hydraulic control exhaust valve 12 opens and the combustion gas is exhausted.

Therefore, while the piston 4 moves by the distance d as shown in FIG. 2, the opening timing of the exhaust valve 12 is delayed. Therefore, by changing the stroke of the piston 4 by adjusting the position of the stopper screw 6, the opening timing of the exhaust valve 12 can be adjusted to a desired timing.

However, in this conventional device, the stroke volume of the piston in the sub-cylinder is manually adjusted and the opening timing of the exhaust valve is thereby changed. The stroke volume of the piston in the cylinder must be manually adjusted each time,
Adjustment takes time and is troublesome, and it also has the disadvantage of poor reliability due to variations due to individual differences.

The present invention was developed in view of these drawbacks, and its purpose is to quickly and accurately automatically set the opening timing of the hydraulic control exhaust valve to the optimum timing in response to changes in operating conditions such as fuel properties. An object of the present invention is to provide a valve opening timing control device for a hydraulically controlled exhaust valve that can be adjusted to the desired timing.

Another object of the present invention is to enable diagnosis of whether the actual valve opening timing is at a predetermined timing when the valve opening timing is controlled to the optimum valve opening timing. The purpose is to provide a control device.

Still another object of the present invention is to provide a valve opening timing control device for a hydraulic control valve that is capable of controlling the opening timing at which the operating cost is minimized.

For this reason, the present invention is designed to
Focusing on the changes in engine speed, average effective pressure, and cylinder pressure when the scavenging hole is open, we detect all of these and also detect the scavenging pressure when the exhaust hole is open, and detect the detected engine speed, average effective pressure, A target value for the cylinder pressure when the scavenging hole is open is generated so that the thermal efficiency is maximized for each scavenging pressure, and the hydraulic pressure is adjusted according to the deviation between the maximum value and the detected value of the cylinder pressure when the scavenging hole is open. The opening timing of the control exhaust valve is automatically controlled, so that the cylinder pressure when the scavenging hole is open corresponds to the state of best thermal efficiency.

Furthermore, there is a detection means for detecting the valve lift of the hydraulic control exhaust valve, and the valve lift state with respect to the crank angle, the engine rotation speed, the average effective pressure, the scavenging pressure, and the cylinder when the scavenging hole is open based on the detection signal of the valve lever 7. A display means for displaying internal pressure, etc. is added, and the valve opening timing can be diagnosed depending on the operating conditions based on the contents displayed on the display means.

In addition, a display means is added to measure and display the fuel consumption at each valve opening timing, and the hydraulic control exhaust valve is adjusted so that the operating cost is minimized based on the fuel consumption displayed on this display means. The valve opening timing can be set manually or automatically.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 3 is a block diagram showing an embodiment of the present invention using a digital arithmetic processing device such as a microcomputer. In the figure, 30 is a calculation process for determining the optimum opening timing of a hydraulic control exhaust valve (hereinafter abbreviated as an exhaust valve) according to a program stored in advance in a program memory 31, diagnosis of the opening timing, and fuel consumption. 32 is an arithmetic processing unit that performs arithmetic processing for displaying consumption; 32 is an arithmetic processing unit; 33 is a random access memory that temporarily stores calculation results during the calculation; and 33 is a A keyboard is used to input various command words and numerical data as well as data on the valve opening timing that minimizes operating costs. 34 is a keyboard used to input constant data such as the connecting rod length and crank radius for calculating the average effective pressure. At the same time, data such as the target cylinder pressure when the scavenging hole is open that provides the best thermal efficiency for each of the engine speed, average effective pressure, and scavenging pressure when the scavenging hole is open under the engine's current operating conditions is stored in advance. The constant memory 35 is a display that displays data necessary for control and diagnosis, such as the valve lift status relative to the crank angle, on each valve opening timing side when the exhaust valve opening timing is optimized according to the operating conditions. The device 36 is an input circuit that transfers output signals of various sensors such as cylinder pressure to the arithmetic processing device 30. In this case, if the output signals of various sensors are analog signals, the input circuit 36 converts them into digital data and transfers the digital data to the arithmetic processing unit 30. Note that the device 30 instructs whether to transfer the output signal of the sensor to the arithmetic processing device 30.

37 is a rotation mark sensor for detecting the rotation speed of the engine, and as shown in the external view of FIG. Alternatively, it is constituted by an optically detected sensor, in which a rotation mark 48 is provided at a position corresponding to the top dead center of the piston, and a rotation mark signal decoy with a predetermined pulse width is taken out every time the piston reaches the top dead center. , this signal RM
is configured to be supplied to the main body section 450 input circuit 36 via a signal line 49. Therefore, the processing unit [
30 can know the current rotational speed N of the engine by sampling this rotation mark signal pigeon and measuring the number of occurrences or the period of occurrence of the signal arc within a predetermined period of time. Furthermore, by measuring the period of the rotation mark signal arc and dividing the measured value into 360 equal parts, the crank angle can be determined in units of 1 degree.

38 is a cylinder pressure sensor that detects the cylinder pressure of the engine,
It is provided within the cylinder, and its output signal PCO is input to the input circuit 36 of the main body 45 via the signal line 50. Therefore, the arithmetic processing unit 30 outputs this cylinder pressure detection signal P.
By sampling co and comparing it with data representing the crank angle, it is possible to know the cylinder pressure Pc5b when the scavenging hole is open.

The average effective pressure P1 can be determined by integrating the detected signal Pco of the cylinder pressure, which changes with the change in the stroke volume, from the bottom dead center to the next bottom dead center.

In this case, there is a very large difference between the cylinder pressure due to combustion after the piston reaches top dead center and the cylinder pressure during scavenging, and a single pressure sensor is used to determine the cylinder pressure over such a large pressure range. Since it is difficult to accurately detect with a resolution of , so that the cylinder pressure can be detected with high accuracy.

Reference numeral 39 denotes a scavenging pressure sensor for detecting scavenging pressure, which is provided in the scavenging pipe, and its output signal Ps is input to the input circuit 36 of the main body 45 via the signal line 51. Therefore, the arithmetic processing unit 1130 can know the scavenging pressure Ps when the scavenging hole is open by sampling the output signal of the scavenging pressure sensor 39 and comparing it with data representing the crank angle.

Reference numeral 40 denotes a fuel flow rate sensor for detecting the fuel flow rate, and as shown in FIG. The signal is inputted to the input circuit 36 of the main body section 45 via the signal line. The fuel flow rate detected by the fuel flow rate sensor 40 is used as reference data for determining the opening timing of the exhaust valve that will minimize operating costs.

Next, reference numeral 41 denotes an actuator that controls the opening timing of the exhaust valve by varying the stroke volume of the piston in the sub-cylinder, using a mechanism as shown in FIG. Note that the cutting cylinder in this actuator 41 can be integrated with the hydraulic actuator 54, but here, the sub-cylinder, piston, stopper screw, pinion and rack mechanism etc. are actively used to change the opening timing of the exhaust valve. The part involved is defined as the actuator for changing the valve opening timing.

42 moves the rackper 55 in the actuator 41 in the direction shown by arrow A in FIG.
6, a motor control circuit 43 rotates the motor 42 according to the amount of change in the opening timing of the exhaust valve; 44 is a position sensor that detects the current position of the rack par 55; its output signal is The signal is input to the input circuit 36 of the main body 45 via the signal line 57.

Reference numeral 46 denotes an exhaust valve lift sensor that detects the valve lift (displacement amount) of the exhaust valve, and its output signal I7r is input to the input circuit 36 of the main body 45 via a signal line 58.

In addition, in FIG. 4, 59 is an exhaust pipe, and 60 is an exhaust valve spring.

FIG. 5 is a flowchart showing the flow of various arithmetic operations for controlling and diagnosing the opening timing of the exhaust valve, which are executed in the above configuration. The operation of the valve opening timing control device for a hydraulic control exhaust valve having the configuration shown in FIG. 3 will be described below with reference to FIG.

First, the arithmetic processing unit 30 detects the current rotation speed N of the engine based on the output signals of the rotation mark sensor 37 in step 1000 rotation speed detection processing.

In the crank angle calculation process of step 101, the crank angle is sequentially calculated based on the output signals of the rotation mark sensor 37. Thereafter, in the scavenging hole opening internal pressure calculation process of step 102, when the crank angle calculated in the crank angle calculation process reaches a value indicating the crank angle when the scavenging hole is open, the arithmetic processing unit 30 detects the cylinder pressure sensor 38. The cylinder internal pressure Pc5b when the scavenging hole is open is detected based on the cylinder internal pressure PCOK detected by. Similarly, step 1
In the scavenging pressure calculation process when the scavenging hole is open in step 03, the scavenging pressure Pso when the scavenging hole is open is detected based on the scavenging pressure Ps detected by the scavenging pressure sensor 39.

While detecting the cylinder pressure Pc5b and the scavenging pressure Pso when the scavenging hole is open in this way, the arithmetic processing unit 30 continues until the piston reaches the next bottom dead center from the bottom dead center in the average effective pressure calculation process in step 104. During one cycle, the cylinder pressure Pc is detected by the cylinder pressure sensor 38 every time the data representing the crank angle advances by one.

and constants such as the length of the connecting rod stored in advance in the constant memory 34, calculate the average effective pressure P1 by executing the calculation process of the calculation formula shown in the following.
Calculate.

is the connecting rod length, and r is the crank radius. In this case, the cylinder pressure Pc detected by the cylinder pressure detection sensor 38
Since o represents relative pressure, the scavenging pressure Ps is added to convert it into a value representing absolute pressure, and the average effective pressure Pi is calculated from the detected value of the absolute cylinder pressure.

Next, the arithmetic processing unit 30 sets the target value Pc5 (N) of the scavenging hole opening timing internal pressure that maximizes the thermal efficiency of the engine for the current rotation speed N detected in step 100 to the first target value in step 105. Constant memory 3 due to generation processing
Generate from 4. Similarly, the target value Pea (Pi) of the scavenging hole opening timing internal pressure that maximizes the thermal efficiency of the engine with respect to the average effective pressure P1 calculated in step 104 is set in the constant memory 34 by the second target value generation process in step 106. Generate from. Further, the target value Pc of the internal pressure when the scavenging hole is opened is set such that the thermal efficiency of the engine is the best with respect to the scavenging pressure Pso detected in step 103 when the scavenging hole is open.
5 (Pso) is generated from the constant memory 34 by the third target value generation process in step 107.

Next, the arithmetic processing unit 30 selects the three target values Pc5(N), Pc5(Pi) in the maximum value selection process in step 108.
), -Pca (Pso), and use this maximum value as the target value P of the internal pressure when the scavenging hole is open to maximize thermal efficiency under the current operating conditions (load and fuel properties).
Determined as c5a.

In other words, in general, in diesel engines, the exhaust valve is opened only under full load and when fuel with specified properties is used, in order to increase the in-cylinder pressure to the permissible limit when the scavenging hole is opened, and to maximize thermal efficiency. Since the valve timing is set, when the engine is under partial load or when fuel with poor properties is used, the average effective pressure and the in-cylinder pressure when the scavenging holes are open decrease, and the thermal efficiency also decreases.

Therefore, in order to control the opening timing of the exhaust valve so that the in-cylinder pressure when the scavenging hole is open is within the range allowed by the design of the engine and to the pressure that maximizes thermal efficiency, first, the rotation speed N, The average effective pressure P1 is detected as a factor representing the current operating condition, and these factors are used as parameters to set the target values pcs(N) and Pc5(Pi) of the scavenging hole opening internal pressure to make the scavenging hole opening internal pressure as high as possible. ) occurs. At the same time, in a diesel engine, there is a condition that the internal pressure when the scavenging hole is open must be lower than the scavenging pressure when the scavenging hole is open to prevent backflow of scavenging air.
Target value (limit value) of the cylinder pressure when the scavenging hole is open, which is allowable under the conditions of the current scavenging pressure P8 and the two target values Pc
5 (Pao) is generated. The three target values Pc5(N) and Pc5(Pi) generated in this manner.

The maximum value of Pc5(Pso) is determined as the target value Pc5a of the in-cylinder pressure when the scavenging hole is opened in order to optimize the thermal efficiency under the current operating conditions.

In this case, the rotation speed is 14. Target values Pc5 (N), F'cs (Pi), Pc5 (Ps
The relationship o) is set, for example, to the relationship shown in FIGS. 6 to 8, and the ship value data corresponding to this relationship is stored in the constant memory 34 in advance. In addition, in FIGS. 6 to 8, the vertical and horizontal axes represent each value with the full load being 100 inches.

After the target value Pc5a of the scavenging hole opening internal pressure is determined in this way, the arithmetic processing unit 30 calculates the deviation between the target value Pc5a and the current value Pc5b in the deviation process of step 09. That is, the deviation P from the current value Pc5b of the scavenging hole open internal pressure calculated in the maximum value selection process.
Find dev. As a result, the increase/decrease value by which the current value pcsb of the internal pressure when the scavenging hole is opened can be determined. Therefore,
In the valve opening timing correction amount calculation process of step 110, the arithmetic processing unit 30 sets the relationship as shown in FIG.
Based on the actuator position correction amount data DAPadj for valve opening timing correction with respect to the deviation Pdev stored as numerical data in the constant memory 34, an actuator position correction amount APadj corresponding to the deviation Pdev is calculated.

Thereafter, in the rack bar position detection process of step 111, the current position of the rack bar 55 is detected from the rack bar position sensor 44, and this current position is determined by the correction ii APa.
The motor 42 is rotated until the distance corresponding to d j has been moved. As a result, the rack bar 55 moves, the position of the stopper screw (see FIG. 1) in the actuator 41 moves, and the stroke volume of the piston in the sub-cylinder is changed. As a result, the opening timing of the exhaust valve is changed, and the scavenging hole opening internal pressure is increased to the target value Pc5a. That is, the opening timing of the exhaust valve is delayed to the timing corresponding to the target value PCsa so that the thermal efficiency of the engine is maximized under the current operating conditions.

In this case, since the amount of movement of the rack bar or the amount of positional movement of the stopper screw per one rotation of the motor 42 can be calculated in advance, the rotation number data of the motor 42 relative to the actuator position correction amount data DAPadj calculated in step 110 If is stored in the constant memory 34 in advance, the opening timing of the exhaust valve can be controlled to the target timing by reading out the rotation number data for this data DAPadj and controlling the rotation number ti of the motor 42.

In this case, the rack bar position sensor 44 can be omitted.

The arithmetic processing unit 30 optimizes the opening timing of the exhaust valve as described above, but after that, in the display process of step 112, the exhaust valve opening timing is optimized for each predetermined crank angle unit based on the output signal LFT of the exhaust valve lift sensor 46. Detect the valve lift state of 3. Furthermore, the rotation speed N after optimizing the valve opening timing.
, mean effective pressure Pi.

The scavenging pressure Pso when the scavenging hole is open, the target value Pc5a and the current value Pc5b of the open internal pressure when the scavenging hole is open, etc. are detected, and these detected values are displayed as a graph or text on the screen of the display device 35 along with a graph of the valve lift state. let FIG. 4 shows an example in which the valve lift state (symbol B) and the change in cylinder pressure (symbol C) are displayed with respect to the crank angle.

In this way, after optimizing the exhaust valve opening timing according to the operating conditions, the valve lift condition and cylinder pressure for each valve opening timing are displayed, and the valve lift of the standard engine measured in advance is displayed. It becomes possible to compare the condition and cylinder pressure, and not only can it be diagnosed whether the opening timing of the exhaust valve is normal, but also whether the operation of the entire exhaust valve system is normal. In this case, there are two methods for diagnosing whether or not the condition is normal: one method is to visually check the display contents, and the other is to perform a comparison process with diagnostic data such as valve lift status regarding a standard engine stored in the constant memory 34 in advance. However, either method may be used; in particular, when the latter method is used, there is an advantage that there is no error caused by individual differences in the diagnostician, and the diagnosis can be made accurately and quickly. In this case, it is not necessary to display all of the various pressure detection values described above, and it is not a stretch to say that the display may be limited to only those essential for diagnosing the valve opening timing. Further, such display processing is essential only when diagnosing the valve opening timing, and can be omitted when only optimization control is performed.

On the other hand, in the display process of step 112, the arithmetic processing unit [30 displays the fuel flow iFQ at the current valve opening timing at the sensor 4.
0 and displayed on the display device 35 as reference data for operating costs. In this case, the measurement time of the fuel light sound by the sensor 40 is determined by the timer 61.

By displaying the fuel flow i (that is, fuel consumption t) per unit time in this manner, it is possible to set the opening timing of the exhaust valve to the timing when the operating cost is minimized. That is, the aforementioned target values Pc5(N), Pc5(Pi), and Pc5(Pso) for optimizing the valve opening timing are as follows:
This is preset on the premise that scavenging conditions are such that backflow of scavenging air does not occur and the scavenging pipe is not contaminated.

Therefore, for example, if the scavenging pipe is allowed to become contaminated to a certain extent, by further delaying the opening timing of the exhaust valve, it is possible to further reduce the energy loss of the exhaust gas and, as a result, to reduce the amount of fuel consumed. On the other hand, in this case, additional work costs will be incurred to remove dirt and the like from the scavenging pipe.

Therefore, by displaying the fuel consumption amount on the side of the exhaust valve opening timing, the fuel consumption amount when the valve opening timing is further delayed can be predicted from this display content. On the other hand, if the valve opening timing is further delayed, the cleaning costs for scavenging pipes, etc. can be predicted empirically. Therefore, when it becomes necessary to operate with top priority on operating costs, the timing for opening the exhaust valve that minimizes operating costs is determined based on the predicted value of fuel consumption and the predicted value of cleaning costs for scavenging pipes, etc. is determined by the operator's judgment, and data representing this valve opening timing is input from the keyboard 33 in the valve opening timing manual setting section in step 113. As a result, in the valve opening timing correction amount calculation process of step 110, the position of the stopper screw in the actuator 41 is corrected based on the manually set valve opening timing data. As a result, operation is possible with minimum operating costs.

Incidentally, although the above description has been made assuming an engine with a single cylinder, the present invention can be similarly implemented in an engine having a plurality of cylinders. Further, although a binion and rack mechanism is used as the actuator for controlling the opening timing of the exhaust valve, the stopper screw may be directly moved by a motor. Further, although the arithmetic processing and control of each unit is performed by a digital arithmetic processing device such as a microcomputer, it may be constructed by combining dedicated circuits according to the content of the arithmetic operations.

As is clear from the above description, according to the present invention, the opening timing of the hydraulic control exhaust valve can be quickly and highly accurately automatically adjusted to the optimal timing according to the operating conditions.

If the configuration is configured to display the valve lift status, the valve opening timing can also be diagnosed, and maintenance of the exhaust valve system 2
Effective for inspection work. Furthermore, if the fuel consumption amount of the valve is displayed at the opening timing, it is possible to determine the opening timing at which the operating cost is minimized, which is effective when operating with top priority given to the operating cost.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 are diagrams showing an example of a conventional device, Fig. 3 is a block diagram showing an embodiment of the present invention, Fig. 4 is an external view thereof, and Fig. 5 is a diagram showing various arithmetic processing used for control. Flowcharts illustrating the flow and FIGS. 6 to 9 are diagrams illustrating examples of relationships between various constants and variables used for control. 30... Arithmetic processing unit, 31... Program memory, 33... Keyboard, 34... Constant memory, 35... Display device, 36... Input circuit, 3
7...Rotation mark sensor, 38...Cylinder pressure sensor, 39...Scavenging pressure sensor, 40...Fuel flow rate sensor, 41...Actuator for changing valve opening timing,
42...Motor, 43...Motor control circuit, 4
4...Rack bar position sensor, 46...Exhaust valve lift sensor, 47...Rotating body, 54...Hydraulic actuator, 55...Rack bar 156...
・Stopper screw. Patent applicant: Mitsui Engineering & Shipbuilding Co., Ltd. Agent: Kazuki Yamakawa GBI≧1 person)

Claims (3)

[Claims] (1) In a valve opening timing control device for a hydraulically controlled exhaust valve in a diesel engine, which controls the opening timing of a hydraulically controlled exhaust valve by adjusting the stroke volume of a noviston in an auxiliary cylinder provided in a hydraulic actuator, the engine speed is controlled. A rotation speed detection means for detecting the rotation speed, an average effective pressure detection means for detecting the average rumble pressure in one engine cycle, a first pressure detection means for detecting the scavenging pressure, and a second pressure detection means for detecting the cylinder pressure. , a first target value generating means for generating a target value of the cylinder internal pressure when the scavenging hole is open with respect to the detected value of the rotation speed; and a first target value generating means that generates a target value of the cylinder internal pressure when the scavenging hole is open with respect to the detected value of the average effective pressure. a second target value generating means for generating a target value of the cylinder pressure when the scavenging hole is open with respect to the detected value of the scavenging pressure; Calculate the deviation from the detected value of cylinder pressure when the scavenging hole is open,
and a control means for adjusting the stroke volume of the piston in the auxiliary cylinder according to the calculated value, and the opening timing of the hydraulically controlled exhaust valve is optimized according to the operating conditions. Valve timing control device. (2) In a valve opening timing control device for a hydraulically controlled exhaust valve in a diesel engine that controls the opening timing of a hydraulically controlled exhaust valve by adjusting the stroke volume of a piston in a sub-cylinder provided in a hydraulic actuator, the engine an average effective pressure detector that detects the average effective pressure in one engine cycle, a first pressure detector that detects the scavenging pressure, and a second pressure detector that detects the cylinder pressure. pressure detection means; first target value generation means for generating a target value of the cylinder pressure when the scavenging hole is open relative to the detected value of the rotational speed; a second target value generating means for generating a target value; a third target value generating means for generating a target value of the cylinder pressure when the scavenging hole is open relative to the detected value of the scavenging pressure; a control means for calculating the deviation between the maximum value and the detected value of the cylinder pressure when the scavenging hole is open, and adjusting the stroke volume of the piston in the sub-cylinder according to the calculated value; and a valve of the hydraulic control exhaust valve. Valve lift detection means detects the lift, and the valve lift state with respect to the crank angle is determined and displayed based on the valve lift detection signal on each valve opening timing side controlled according to changes in operating conditions, and the valve lift state is determined and displayed with respect to the crank angle. Display means for displaying at least one of rotational speed, average effective pressure, scavenging pressure when the scavenging hole is open, a detected value of the cylinder internal pressure when the scavenging hole is open, and a target value of the cylinder internal pressure when the scavenging hole is open. The hydraulic exhaust valve is equipped with a hydraulic exhaust valve that optimizes the opening timing of the hydraulic control valve according to the operating conditions, and makes it possible to diagnose the opening timing according to the operating conditions based on the display contents displayed on the display means. Valve opening timing control device. (3) In a valve opening timing control device for a hydraulically controlled exhaust valve in an internal combustion engine that controls the opening timing of a hydraulically controlled exhaust valve by adjusting the stroke volume of a piston in a sub-cylinder provided in a hydraulic actuator, the engine rotational speed is a rotation speed detection means for detecting the average effective pressure in one engine cycle, a first pressure detection means for detecting the scavenging pressure, and a second pressure detection means for detecting the cylinder pressure. a first target value generating means for generating a target value of the cylinder internal pressure when the scavenging hole is open with respect to the detected value of the rotational speed; a second target value generating means for generating a target value of the cylinder internal pressure when the scavenging hole is open relative to the detected value of the scavenging pressure; a control means for calculating the deviation from the detected value of the cylinder pressure when the scavenging hole is open, and adjusting the stroke volume of the sub-cylinder according to the calculated value; and controlling the stroke volume of the piston in the sub-cylinder manually or automatically. and a fuel consumption measuring means that measures and displays the fuel consumption per unit time at each valve opening timing that changes by adjusting the stroke volume of the piston in the sub-cylinder. In addition to optimizing the opening timing of the hydraulic control valve in accordance with A valve opening timing control device for a hydraulically controlled exhaust valve that can be set manually or automatically.