JPS61247843A - Monitoring safety device for tappet valve of electronic controlled internal-combustion engine - Google Patents

Abstract

PURPOSE:To make it possible to operate an internal combustion engine safely, by deciding that something is wrong with a tappet valve, when counted number of a pulse signal, which is counted as regarding the rise point and the trail point of a tappet valve motion signal as triggers, becomes over the preset limit. CONSTITUTION:A tappet valve motion signal which corresponds to the motion of an exhaust valve 4, is input in a monitoring device 40 by a sensor 41, and a pulse signal which corresponds to the crank rotation angle, is also input in the monitoring device 40 by an encoder 16. Then,the pulse signal is counted as regarding the rise point and the trail point of the tappet valve motion signal as triggers, and a signal is output from the monitoring device 40 when said counted number becomes over the preset limit. By this signal, the second driving circuit 26 stops fuel feeding toward a cylinder 1, through operating a fuel shut- off valve 13, and at the same time, keeps the exhaust valve 4 to be opened, through quickly releasing the air in the air spring cylinder lower chamber of an air spring piston 47 which is moved in linkage the exhaust valve 4, and filling up the air spring cylinder upper chamber with air.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a monitoring and safety device for safely handling emergencies in electronically controlled internal combustion engines.

Conventional technology Electronically controlled internal combustion engines, for example, attempt to achieve optimal operational control of diesel engines using electronic computers, and specifically control the crank angle, rotational speed, torque, and various parts of the diesel engine. The system detects the pressure, temperature, composition of exhaust gas, etc., processes these operating data with a computer according to a predetermined program, determines the optimal operating control conditions, and controls the determined conditions. The command information is for opening and closing the starting valve, intake valve, exhaust valve, fuel injection valve, etc. of the diesel engine according to the crank angle.

FIG. 4 shows the overall configuration of this electronically controlled internal combustion engine. A diesel engine usually has a plurality of cylinders (1) from the first cylinder to the Nth cylinder, and each cylinder (1) has a starting valve (2), an air supply valve (3), and an exhaust valve. (4)
, a fuel injection valve (5) is equipped. (6)-(9)
is an actuator that operates these multiple valves (2) to (5). Fuel oil is supplied to the fuel injection valve (5) by a fuel cylinder (b) from a fuel tank αQ. (2
) is the fuel voltage regulator, (to) is the fuel cutoff valve, and a4 is the reverse valve.

On the other hand, the rotation angle of the crankshaft is detected by an encoder Q, and is input to a central processing unit (hereinafter referred to as CPU) via an input capacitor Qη and a data path. Note that the detection output of the encoder QIS is also sent to the diesel engine control circuit so and the frequency/voltage converter eη as crank angle information. The signal converted into a voltage signal according to the rotational speed by the frequency/voltage converter η is input to the CPU Q via the analog/digital converter 4 and the data path (to) described above.

In addition, the pressure, temperature, exhaust gas composition, etc. of each part of the diesel engine are also detected by sensors (Sl) to (S6), and after the data is digitally converted by the analog/digital converter (2), the CPU α Entered into a groan.

The CPU Q'J reads the operating command input from the setting input/display device (2), and based on this operating command, calculates the angle, rotation speed, pressure of each part of the engine, etc. input from the analog/digital converter, etc. Using data representing the operating state of the engine, such as temperature and exhaust gas composition, control variables and operator calculations for optimal control of the engine are executed according to a predetermined program. Then, from this calculation result, a control command for the fuel pump (b) is created and digitalized.
Fuel pump (b) via I//analog converter (b)
control. Furthermore, the CPU α groans from the calculation results when the start valve (
2), air supply valve (3), exhaust valve (4), fuel injection valve (5)
A multi-valve control command is created and output to the diesel engine control circuit (e).

The diesel engine control circuit reads control commands from the CPU 00 and sends control information corresponding to the crank angle information obtained from the encoder αQ to the first and second drive circuits. The first drive circuit □□□ controls a control valve that controls the actuation timing of the actuator (9) to operate the fuel injection valve (5).

The second drive circuit (to) is the actuator (6) (7)
The control valves (c) @ (7) that control the operation timing of (8) are operated to operate the start valve (2), the air supply valve (3), and the exhaust valve (4), as well as the fuel cutoff valve (2). ). Note that the hydraulic pressure generated by the hydraulic pump (2) is used as the power source for driving the actuators (6) to (9).
A pressure accumulator is installed on the outlet side of the pump to prevent pulsation and to make effective use of the two springs. (To) is the pressure regulating valve,
(To) is the oil tank, (To) is the flow control valve.

In such a front control type internal combustion engine, it is possible to control the operation optimally for each cylinder (1), even when the cylinders (1) have different characteristics due to the cylinder (1) arrangement. , multiple valves (2) for each cylinder (1)
- (5) etc. are each a unitized drive system, and a method is adopted in which cylinders are added according to the number of cylinders.

Of course, the encoder DISCPUQQ, hydraulic pump CITJ, etc. can be shared by one engine.

Problems to be Solved by the Invention With such a conventional configuration, if the electronic equipment and hydraulic equipment used in each of these valve drive systems should malfunction, the failure of the exhaust valve drive system in particular would be a serious problem. There is a possibility of causing a serious accident. For example, in the case of a Uniflow engine (2 cycles/I/), the insertion/exhaust timing is as shown in Figure 5, and the effective compression of a normal engine is as shown by the solid line A in Figure 6. When the valve is closed, the operation starts as 'EC'.However, if the exhaust valve closes due to some kind of failure and does not operate in that state, effective compression will occur at the scavenging port as shown by the dotted line B in Figure 6. After "SC" when the hole is closed, the effective compression PC, as shown by the dotted line B, becomes about 1.4 times as much as the normal case shown by the solid line A. 6th
In the figure, vII represents the cylinder stroke volume at the beginning of compression.

Therefore, the exhaust valve is closed! ! If fuel is injected into the "SO" when the scavenging port is opened, the cylinder maximum combustion pressure Pm will exceed the planned value as indicated by the dotted line B in FIG. 6, which is dangerous.

In addition, since the combustion exhaust gas in the cylinder after combustion expansion is not discharged from the exhaust valve, it will flow back into the scavenging pipe from the scavenging port, causing accidents such as damage due to the rapid propagation of pressure waves to the turbocharger. Become.

The present invention solves these problems by monitoring the behavior of the exhaust valve drive system in particular, and minimizing the above-mentioned abnormal situation in the event that a failure occurs and the exhaust valve stops operating. In order to limit the limit, open the safety device that stops the fuel supply to the cylinder and the exhaust valve on the safe side! The purpose of the present invention is to provide a monitoring safety device that operates safety equipment that maintains lK.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses as input a detection signal corresponding to the behavior of the valve train and a pulse signal corresponding to the rotation angle, and detects the rise timing of the valve train behavior signal. a monitoring device that counts the pulse signal using the point and the falling point as triggers, and issues an external signal when the count exceeds a set range; and an external signal issued by the monitoring device as input;
A device that activates a safety device that stops the fuel supply to the internal combustion engine, and the output of the output device rapidly releases the air in the lower chamber of the air spring piston that is linked to the valve train, and simultaneously releases the air in the upper chamber of the air spring piston. The valve is filled with air and has an air spring cylinder that holds the valve in an open state.

With this configuration, the monitoring device determines that an abnormality has occurred in the valve train when the count of pulse signals, which are counted using the rising and falling points of the valve behavior signal as triggers, exceeds the set range. Then, the fuel supply to the internal combustion engine is stopped, and the air spring cylinder is driven to keep the valve open, thereby quickly avoiding a dangerous situation and performing safe operation.

EXAMPLE An example of the present invention will be described below based on the drawings. 1st
2 is an enlarged configuration diagram illustrating the exhaust valve drive system, and FIG. 3 is a waveform diagram illustrating the operation of the monitoring device. In the drawings, the same reference numerals as in FIG. 4 indicate the same parts, so the explanation will be omitted.

In Figures 1 and 2, ■ is a valve train monitoring device that monitors the behavior of the exhaust valve, the target is a behavior detection sensor that detects the behavior of the exhaust valve (4), and the curve is the supply fin air control valve for the air spring. ,
- is a discharge fin air control valve for an air spring, (Foundation) is a check valve, (46a) is an air spring cylinder, (46a) is an air spring cylinder lower chamber, (46b) is an air spring cylinder upper chamber,
The first one is the air spring piston, - is the air tank, and - is the scavenging chamber.

Next, the operation of the device of the present invention will be explained with reference to FIG. The monitoring device (a) receives a valve lift signal a (Fig. 3 (a)) corresponding to the behavior of the exhaust valve by the sensor (2) and an encoder α.
Pulse signal d corresponding to the rotation angle of the shift flank angle due to Q
(FIG. 3(e)) is input. First, monitoring of the valve opening period is performed by applying a trigger at the valve opening rising point A of the exhaust valve and counting the number of pulse signals d up to the valve closing falling points B. On the other hand, monitoring of the valve closing period is performed by applying a trigger at the valve closing falling point B of the exhaust valve, and counting the number of pulse signals d up to the valve opening falling point B. Here, the sensor (sensor) may be one that outputs a signal that can distinguish between open and closed valves, and it is not necessarily necessary to use a high-grade lift meter, for example, a proximity switch, etc.
An N-OFF signal may also be used. Also, one trigger point A.

Setting B is based on the monitoring circuit (G) K according to the sensor output used.
The voltage value can be adjusted by Further, it is preferable that the behavior of the exhaust valve drive system is detected by the exhaust valve (4) itself, which is the final end, rather than by the behavior of the hydraulic pressure, control valve (2), and actuator (8) in the middle of the hydraulic circuit.

Figure 3 (b) is a waveform diagram of the drive oil pressure of the exhaust valve, Figure 3 (c)
) shows a waveform diagram of the air spring pressure in the lower chamber of the air spring cylinder, and signals obtained from these waveforms may be used as the valve behavior signal instead of the valve lift signal a. If an abnormality occurs in the drive system and the bus count number during the opening/closing period described above exceeds the opening/closing period preset by the CPU α, a signal is issued (an alarm, etc. is displayed). include)
. In response to the above signal, the second drive circuit □□□ operates the fuel cutoff valve of the corresponding cylinder (1).
). At the same time, the second drive circuit is connected to the supply line air control valve (6) (three-way switching valve) to the air spring cylinder upper chamber (46b) and the discharge line air control from the air spring cylinder upper chamber (46b). Operate the six wheels (three-way switching valve).

Here, due to its three-way valve structure, the exhaust fin air control valve (46b) normally communicates with the air spring cylinder upper chamber (46b) to the outside, and when the exhaust valve (4) is opened, the air spring cylinder upper chamber (46b) ) in the lower chamber (46a) to prevent the valve opening resistance from becoming negative pressure.
) are blocked off. When the safety equipment is activated, the air spring cylinder upper chamber (46b) of the discharge fin air control valve
The connection port to the air spring 5/cylinder lower chamber (4
6a) is communicated with the outside through this air control six wheel, and serves to rapidly discharge the air in the air spring cylinder lower chamber (46a).

On the other hand, the supply fin air control valve) due to its three-way valve structure usually connects the air tank to the air spring cylinder lower chamber (
46a) through a reversal valve to replenish air leakage from the air spring cylinder lower chamber (46a), and the connection port to the air spring cylinder upper chamber (46b) is blocked. . When the safety device is activated, the connection port of the supply line (air control valve) to the air spring cylinder lower chamber (46a) is shut off, and the connection port to the air spring cylinder upper chamber (46b) is opened to supply air; It works to open the exhaust valve (4).

In this way, when the exhaust valve (4) becomes abnormal in the closed state, during the expansion stroke, the high cylinder internal pressure P2 causes the air to flow back into the scavenging chamber once, but at this time, the reduced cylinder pressure When the internal pressure P2 becomes equal to the scavenging pressure P, (usually Z5atg or less at rated load), the pressure FA in the air spring cylinder upper chamber (46b) overcomes the cylinder internal pressure load Fv and the exhaust valve (4 ) opens,
From the next cycle, the valve will be kept open on the safe side.
Abnormal voltages are prevented.

Furthermore, if an abnormality occurs while the valve is in the open state, that state is maintained, so it is very safe.

In addition to the effects of the invention, by using the valve train monitoring safety device of the present invention, it is possible to prepare for an emergency situation while monitoring abnormal situations in the valve drive system, and even if an abnormal situation occurs, a dangerous situation can be prevented. You can quickly avoid this and drive safely. Moreover,
° Only a simple device needs to be installed, and the installation of a complicated backup system is simple and safe.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of the device of the present invention, Fig. 2 is an enlarged view of the main parts, Fig. 3 is a waveform diagram for explaining the operation, and Fig. 4 is an overall configuration diagram of the electronically controlled internal combustion engine. FIG. 5 is a timing diagram of insertion and exhaust in the case of a Uniflow engine (2 cycles/I/), and FIG. 6 is a characteristic diagram for explaining the effective compression of the engine in normal and abnormal conditions. (1)...Cylinder, (3)...Air supply valve, (4)...
...Exhaust valve, (5)...Fuel injection valve, (To)...Fuel cutoff valve, tm...Encoder, (1)...Central processing unit (CPU), (To)... Setting input/display device, (to)...Second drive circuit, (2)...Operating hydraulic pump, ■...Valve train monitoring circuit, Work...Behavior detection sensor, Support...Supply Line air control valve, -...Discharge fin air control valve, ■...Check valve, -...Air spring cylinder, (46a) (46b)...Air spring cylinder lower chamber and upper chamber, ...Air spring piston, (Foundation)
...Air tank, -...Scavenging room agent Mori
Hon Yoshihiro 3 9 i Figure 5

Claims (1)

[Claims] 1. A detection signal corresponding to the behavior of the valve train and a pulse signal corresponding to the rotation angle are input, and the pulse signals are counted using the rising and falling points of the valve train behavior signal as triggers, and the count number is set. A monitoring device that emits an external signal when the specified range is exceeded; a device that receives the external signal generated by the monitoring device as input and operates a safety device that stops fuel supply to the internal combustion engine; and an output device that uses the output device to An electronically controlled type having an air spring cylinder that rapidly releases the air in the lower chamber of the air spring piston that is linked to the valve train, and also fills the upper chamber of the air spring piston with air to keep the valve open. Valve train monitoring safety device for internal combustion engines.