JP3135634B2 - Air spring type valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air spring type valve train for an internal combustion engine.

[0002]

2. Description of the Related Art In a valve train of an internal combustion engine, an air chamber is provided in place of a steel coil spring, and an intake valve and an exhaust valve are urged in a valve closing direction by compressed air supplied to the air chamber. Such an air spring type valve operating device is conventionally known (for example, Japanese Utility Model Laid-Open No. 63-14808).

FIG. 10 is a longitudinal sectional view of a main part of this type of air spring type valve operating apparatus.
The valve guide 103 is fixedly supported by the valve guide 103. A lifter 104 is fixed to the shaft end of the valve element 101, and the lifter 104 further includes a cylinder head 102.
Is fitted inside a lifter guide 105 formed on the upper wall of the lifter. 106 is an air supply path, 107 is an air chamber, and 108 is a cam.

In the air spring type valve operating apparatus, when the lifter 104 is pushed down by rotation of the cam 108, the valve body 101 moves in the direction of arrow X to open the valve, while when the lifter 104 is not pushed down. Is closed by the air pressure of the air chamber 107. In the air spring type valve operating device, the natural frequency can be set higher than that of the coil spring, so that the operation followability of the valve element 101 is improved even when the engine is rotated at a high speed. be able to.

[0005]

In the air-spring type valve operating apparatus, since air leaks from a seal portion such as a gap between the lifter 104 and the lifter guide 105, a necessary amount of air is supplied to the air chamber 107. Need to be replenished.

However, the required amount of air to be supplied to the air chamber 107 varies depending on the operating state of the engine and the state of deterioration of the seal.

Further, if a large amount of air leaks from the seal portion or the like, the pressure in the air chamber 107 is reduced and the spring load due to the air pressure is reduced, thereby lowering the permissible rotation speed of the valve train and causing engine damage. There is a risk of doing so.

Further, since the pressure in the air chamber 107 gradually decreases after the engine is stopped, when the engine is started with the pressure in the air chamber 107 excessively reduced, the spring load of the air chamber 107 is not desired. There is a danger that the operating performance of the engine will be impaired without immediately returning to the spring load.

The present invention has been made in view of such circumstances, and provides an appropriate amount of air to an air chamber in accordance with an operation state and an internal combustion engine having a security function in a case where the amount of air is insufficient. An object of the present invention is to provide an air spring type valve train.

[0010]

In order to achieve the above object, the present invention provides an air pressure source, an air chamber supplied with air pressure for urging an intake valve and an exhaust valve in a valve closing direction, and the air chamber. an air supply passage for communicating the chamber with the air pressure supply source, before
Pressure detecting means for detecting the pressure of the air supply path;
A control valve interposed in the air supply passage and at least an engine
An operating state that detects the operating state of the engine including the gin speed
State detecting means, and the air detected by the operating state detecting means.
Target pressure for calculating target pressure value based on engine speed
Calculating means, and the pressure detected by the pressure detecting means is
At least the target calculated by the target pressure calculating means
Pneumatic control for controlling the control valve to reach a pressure value
Means for controlling the operation of the control valve by the air pressure control means.
The pressure detected by the pressure detection means reaches the target pressure.
If not, respond to the pressure detected by the pressure detection means.
And an operating state control means for controlling the operating state of the engine .

Further , the present invention provides the above-mentioned air spring type valve train.
The operation of the engine is controlled by the operation state control means.
When the condition is controlled, the pressure in the air supply
It is characterized by having display means for displaying that the standard pressure has not been reached .

[0012]

According to the above construction, during the operation of the engine, the control valve is controlled by the air pressure control means so that the pressure of the air supply passage reaches at least the target pressure, and when the pressure of the air supply passage does not reach the target pressure. The operating state of the engine is controlled by the operating state control means in accordance with the pressure detected by the pressure detecting means. When the pressure of the air supply passage is decreasing, the display means displays that the pressure is decreasing.

[0013]

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram showing an embodiment of an air spring type valve train for an internal combustion engine according to the present invention.

In FIG. 1, reference numeral 1 denotes a DOHC in-line four-cylinder internal combustion engine (hereinafter simply referred to as "engine"). An intake pipe 2 is connected to an intake port of the engine 1, and an exhaust pipe 45 is connected to an exhaust port. Is connected. Further, a throttle body 3 is provided in the middle of the intake pipe 2, and a throttle valve 3 'is disposed therein. A throttle valve opening (θTH) sensor 4 is connected to the throttle valve 3 ′, and outputs an electric signal corresponding to the opening of the throttle valve 3 ′ to output an electronic control unit (hereinafter “EC”).
U ") 5.

A branch pipe 6 is provided downstream of the throttle valve 3 ′ of the intake pipe 2, and an absolute pressure (PBA) sensor 7 is attached to a tip of the branch pipe 6. The PBA sensor 7 is electrically connected to the ECU 5, and
The absolute pressure PBA is converted into an electric signal by the PBA sensor 7 and supplied to the ECU 5.

An intake air temperature (TA) sensor 8 is mounted on the pipe wall of the intake pipe 2 on the downstream side of the branch pipe 6, and the intake air temperature TA detected by the TA sensor 8 is converted into an electric signal.
It is supplied to the ECU 5.

The fuel injection valve 9 is provided for each cylinder in the middle of the intake pipe 2 and between the engine 1 and the throttle valve 3 ', is connected to a fuel pump (not shown), and is electrically connected to the ECU 5. The ECU 5 is connected to control the valve opening time of fuel injection by a signal from the ECU 5.

An engine coolant temperature (TW) sensor 10 composed of a thermistor or the like is inserted into a cylinder wall of the cylinder block of the engine 1 filled with coolant, and the engine coolant temperature TW detected by the TW sensor 10 is converted into an electric signal. The converted data is supplied to the ECU 5.

An engine speed (NE) sensor 11 and a cylinder discrimination (CYL) sensor 12 are mounted around a camshaft or a crankshaft (not shown) of the engine 1.

The NE sensor 11 outputs a signal pulse (hereinafter referred to as "TDC signal pulse") at a predetermined crank angle position every time the crankshaft of the engine 1 rotates 180 degrees, and the CYL sensor 12 outputs a predetermined pulse of a specific cylinder. At the crank angle position, TDC signal pulses are output, and these TDC signal pulses are supplied to the ECU 5.

The ignition plug 13 of each cylinder of the engine 1
It is electrically connected to the ECU 5, and the ignition timing is controlled by the ECU 5.

The cylinder head of the engine 1 has an air-spring type valve train control unit 14 (hereinafter referred to as "valve train control unit").
The valve train control unit 14 is electrically connected to the ECU 5, and the operation thereof is controlled by the ECU 5.

The ignition switch 15 and the starter switch 16 are electrically connected to the ECU 5.
5 and the on / off state signal of the starter switch 16 is E
It is supplied to CU5.

Further, the ECU 5 has a light emitting diode (LE)
D) and other first to third display lamps 17 to 19 are connected. The first display lamp 17 is turned on when the pressure of an air supply passage, which will be described later, is lower than a target pressure to notify the driver of the pressure drop. The second display lamp 18 is turned on when the pressure of the air supply passage reaches a predetermined pressure to notify the driver of the completion of the pressure supplement. Further, the third display lamp 19 is lit when the pressure supply of the air supply passage cannot be supplemented for the reason described later, and notifies the driver of the fact.

The ECU 5 has an input circuit 5a having a function of shaping input signal waveforms from the above-described various sensors, correcting a voltage level to a predetermined level, converting an analog signal value to a digital signal value, and the like, and a central processing unit. Circuit (hereinafter “CP
U ") 5b, and R for storing various arithmetic programs executed by the CPU 5b, various maps, arithmetic results, and the like.
A storage means 5c comprising an OM and a RAM, the fuel injection valve 9, the ignition plug 13 and the first to third display lamps 17;
And an output circuit 5d for supplying a drive signal to the driving signals to the driving signals.

FIG. 2 is a longitudinal sectional view of an essential part of the engine 1. The engine 1 has a cylinder block 22 having four cylinders 21 in which pistons 20 are fitted in parallel, and a cylinder block 22 of the cylinder block 22. And a cylinder head 23 coupled upward. In addition, the cylinder head 23
A pair of intake ports 24a and a pair of exhaust ports 24b are formed at portions corresponding to above the piston 20, and the intake ports 24a are connected to intake ports 25a opened on one side of the cylinder head 23. 24b is connected to an exhaust port 25b opened on the other side surface of the cylinder head 23.

The valve guides 26a and 26b fixed to the cylinder head 23 have a pair of intake valves 27a and exhaust valves 27a.
b is inserted, and the intake port 24a and the exhaust port 24b can be opened and closed.

Specifically, the intake valve 27a and the exhaust valve 27
b is in contact with cams 29a and 29b via lifters 28a and 28b and shims 50a and 50b having a substantially U-shaped cross section, and a cotter is provided around the shaft ends of the intake valve 27a and the exhaust valve 27b. Air piston 3 through 30a, 30b
1a and 31b are attached. Further, a concave groove is formed at an appropriate position on the outer peripheral surface of each of the air pistons 31a and 31b.
Rings 32a and 32b are fixed to the concave grooves, and outer peripheral surfaces of the air pistons 31a and 31b are lifters 28a and 28b.
b is slidable on the inner peripheral surface. Furthermore, lifter 2
8a, 28b are fitted inside lifter guides 33a, 33b formed above the cylinder head 23,
Air chambers 34a and 34b are defined by portions surrounded by a and 28b and lifter guides 33a and 33b.
The intake and exhaust valves 27a, 27b and the cams 29a, 29
b, air chambers 34a, 34b, and air pistons 31a,
The valve trains 35a and 35b are constituted by 31b and the like.

The thus constituted valve trains 35a, 35
In b, the intake valves 27a and the exhaust valves 27b move up and down via the lifters 28a and 28b by the rotational driving of the cams 29a and 29b to open and close the intake valves 27a and the exhaust valves 27b. The air supply paths 36a, 36b constituting the system control unit 14
The air pressure supplied to 34b seals the intake port 24a and the exhaust port 24b.

FIG. 3 is a block diagram showing the outline of the valve train control unit 14. As shown in FIG.

The air supply passage 36 is branched at its tip into an air supply passage 36a for an intake valve and an air supply passage 36b for an exhaust valve, and four side walls of the air supply passages 36a and 36b are provided respectively.
Individual pipes 36'a, 36'b are provided in a branched manner, and can communicate with the air chambers 34a, 34b of the respective valve trains 35a, 35b. 37a and 37b are check valves.
Reference numerals a and 38b denote relief valves that open when the air chambers 34a and 34b reach or exceed the allowable limit pressure.

An accumulator 39 as an air supply source is connected to the upstream end of the air supply passage 36, and the accumulator 39 has an accumulator pressure (P
AC) The sensor 40 is inserted. The PAC sensor 40 is electrically connected to the ECU 5, and the accumulated pressure PAC detected by the PAC sensor 40 is converted into an electric signal and supplied to the ECU 5.

An air pump 41 is connected to the accumulator 39, and the air pump 41 is connected to the ECU 5
The supply of air to the accumulator 41 is controlled by a signal from the ECU 5.

The air supply path 36 is an intake air supply path 36a.
A line pressure (PL) sensor 42 is provided slightly upstream of a branch point (indicated by A in the figure) that branches into the exhaust air supply path 36b. The PL sensor 42 detects the pressure of the air supply path 36 (hereinafter, referred to as “actual line pressure”) and supplies an electric signal to the ECU 5.

A control valve 43 is provided in the air supply passage 36 upstream of the PL sensor 42.
A pressure regulating valve 44 is interposed on the upstream side. The control valve 43 and the pressure regulating valve 44 are both electrically connected to the ECU 5, the control valve 43 opens and closes in response to a signal from the ECU 5, and the pressure regulating valve 44 operates in accordance with a signal from the ECU 5 to control the air pressure conveyed from the accumulator 39. To adjust.

FIG. 4 is a flowchart showing a control procedure of the valve train control unit 14 during the operation of the engine. This program is executed in synchronization with generation of a TDC signal pulse.

First, the engine speed NE is detected by the NE sensor 11 (step S1).
A target pressure PLTAG of the air supply passage 36 (hereinafter, referred to as “target line pressure”) is calculated based on E (step S).
2).

The target line pressure PLTAG is calculated by searching a PLTAG map stored in the storage means 5c (RAM) in advance. That is, as shown by the solid line in FIG. 5, the PLTAG map has map values PLTAG0 to PLTAG0 corresponding to the engine speeds NE0 to NE4.
PLTAG2 is given, and a map value corresponding to the engine speed NE is read out or calculated by an interpolation method. As is clear from FIG. 5, the target line pressure PLTAG is set low to reduce the friction of the valve trains 35a and 35b when the engine speed NE is low, and is set when the engine speed NE is high. It is set high to prevent the intake valve 27a and the exhaust valve 27b from jumping or bouncing. In other words, the target line pressure PLTAG value is limited to an allowable rotation speed at which friction, jump, and the like do not occur. As shown by the broken line in FIG. 5, the characteristic of the target line pressure PLTAG with respect to the engine speed NE is appropriately set according to the characteristics and purpose of the engine. It is preferable that the PLTAG value is appropriately corrected in accordance with the operating state of the engine such as the atmospheric pressure PA and the engine cooling water temperature TA.

Next, in step S3, the actual line pressure is detected by the PL sensor 42, and the detected actual line pressure P
It is determined whether or not L has reached the target line pressure PLTAG, that is, whether or not PL ≧ PLTAG is satisfied (step S4). If the answer is affirmative (YES), the control valve 43 is closed (step S5), and the program ends. Thus, when PL ≧ PLTAG is satisfied, the air chambers 34a and 34b are filled with the actual line pressure PL that is at least equal to or higher than the target line pressure PLTAG.

On the other hand, if the answer to step S4 is negative (NO),
That is, when PL <PLTAG, the routine proceeds to step S6, where the PAC sensor 40 detects the accumulator pressure PAC, and then determines whether or not the accumulator pressure PAC has reached the target line pressure, that is, whether PAC ≧ PLTAG holds. (Step S7). If the answer is affirmative (YES), the actual line pressure PL has not reached the target line pressure PLTAG even though the accumulator pressure PAC has reached the target line pressure PLTAG, and the valve train 35a, It is determined that there is a large amount of air leak in the seal portion 35b, etc., and the set pressure PR of the pressure regulating valve 44 is determined based on the equation (1) (Step S).
8).

PR = PLTAG + PO (1) Here, PO is a predetermined pressure, and for example, PO = PL such that the set pressure PR becomes equal to or higher than the target line pressure PLTAG.
TAG × 0.1 may be set, for example, 0.5 kg / c
m ² of about may be set to a constant value. Then, after the setting of the pressure adjusting valve 44 is performed in this way, the control valve 43 is opened (step S9), and the program ends. That is, since the set pressure PR is set to be equal to or higher than the target line pressure PLTAG, air is supplied to the air chambers 34a and 34b with an air pressure equal to or higher than the target line pressure PLTAG.

On the other hand, if the answer to step S7 is negative (NO),
That is, when PAC <PLTAG, the air pump 41
In this case, the accumulator pressure 39 does not reach the target line pressure PLTAG due to performance deterioration of the valve. In such a case, the actual line pressure PL is reduced to the target line pressure PL even when the control valve 43 is fully opened.
TAG cannot be reached. Therefore, in this case, the process proceeds to step S10 to set the pressure PR of the pressure regulating valve 44.
Is set to PR ≧ PAC, the control valve 43 is opened, and the accumulator pressure PAC (<
PLTAG) (step S11), and then the allowable limit rotational speed NEL corresponding to the accumulator pressure PAC.
MT is calculated (step S12). This allowable limit rotational speed NELMT is specifically stored in advance in the storage unit 5c (RA
It is calculated by searching the NELMT map stored in M). That is, in the NELMT map, as shown in FIG. 6, map values NELMT0 to NELMT are given to the accumulator pressures PAC0 to PAC4, and the permissible limit rotational speed NELMT is read out by this map search or by an interpolation method. Is calculated.

Next, in step S13, the NELMT
Outputs the value and sets the engine speed NE to the allowable limit speed NE.
LMT is forcibly reduced to stop ignition (ignition cut) or stop fuel supply (fuel cut), and then the first display lamp 17 is turned on to notify the driver of a decrease in the actual line pressure PL (step S14). ), End this program.

As described above, in the air spring type valve train, the actual line pressure PL is at least the target line pressure PLT.
By controlling to reach AG, the valve train 35
The air chambers 34a and 34b can be supplied with air of a desired pressure even if a large amount of air leaks from the seal portions a and 35b, thereby avoiding adverse effects on the opening and closing operations of the intake valve 27a and the exhaust valve 27b. can do.

When the accumulator pressure 39 does not reach the target line pressure PLTAG due to performance deterioration of the air pump 41 or the like, the detected line pressure PL (= PAC) at that time.
The engine can be operated at the permissible limit rotational speed NELMT according to the ignition cut or the fuel cut, and the first display lamp 17 is turned on, so that the driver can quickly know the pressure drop, and the actual line pressure PL
Swift response is possible.

FIGS. 7 and 8 are flowcharts showing a control procedure in the valve train control unit 14 when the engine is started. This program is executed when the ignition switch 15 is turned on.
It is executed in synchronization with the switching to the state.

In step S21, both the flag FA and the flag FB are set to "0" for initialization. Next, PAC
The accumulator pressure PAC is detected by the sensor 40 (step S22), and whether or not the accumulator pressure PAC has reached the starting pressure PLST, that is, PAC ≧ PLS
It is determined whether or not T is satisfied (step S23). Here, the starting pressure PLST is set to a minimum line pressure necessary for starting the engine, for example, 3 kg / cm ² . And
If the answer is negative (NO), accumulator pressure PAC
The air pump 41 is turned “ON” to at least reach the starting pressure PLST (step S24), and then it is determined whether or not the flag FA is set to “1” (step S25). Then, in the first loop, FA = 0 remains set (see step S21), and the answer to step S25 is negative (NO), and the first timer t
mTP is set to a predetermined time T1, and the first timer tm
After starting the TP (step S26), the flag F
A is set to "1" (step S27). Here, the predetermined time T1 is set to a time (for example, 5 s) from when the air pump is turned “ON” to when the accumulator pressure PAC reaches the starting pressure PLST. Further, the predetermined time T1 may be variable according to the accumulator pressure PAC. Next, the process waits for the first timer tmTP to become "0" (step S28), and after confirming that the first timer tmTP has become "0", returns to step S22.

Then, again in step S23, PAC ≧ P
It is determined whether or not LST is established. The answer is negative (N
In the case of O), the accumulator pressure PAC is equal to the starting pressure PLS even though the air pump is operating with "ON".
T does not reach T, and at this point the flag FA has already been set to "1" (step S27).
Reference) The answer in step S25 is affirmative (YES). Therefore, proceeding to step S29, the air pump is set to “OF”.
F ", and further turns on the third display lamp 19 (step S30), and the accumulator pressure PA becomes the predetermined pressure PLST.
Notify the driver that the pressure will not be increased to this point and end this program.

On the other hand, if the answer in step S23 is affirmative (YE
S), that is, the accumulator pressure PAC is equal to the starting pressure PL
If it has reached ST, the flag FA is set in step S31.
Is "1". And PAC ≧ P from the beginning
If LST is established, FA = 0 remains set, so the set pressure of the pressure regulating valve 39 is determined based on the equation (2) (step S32).

PR = PLST + P1 (2) Here, P1 is a predetermined pressure, and for example, P1 = PLST × so that the set pressure PR becomes higher than the starting pressure PLST.
It is set to 0.1.

When PAC ≧ PLST is satisfied for the first time since the flow of steps S24 to S28 is executed, the answer to step S31 is affirmative (YES),
After the air pump 41 is turned “OFF”, the process proceeds to step S32, and the set pressure PR of the pressure adjusting valve 44 is calculated.

After setting the pressure regulating valve 44 to the desired pressure in this way, the flow shown in FIG. 8 is executed. That is, the actual line pressure PL is detected by the PL sensor 42 (step S34), and the actual line pressure PL becomes the starting pressure PLS.
It is determined whether or not T has been reached, that is, whether or not PL ≧ PLST holds (step S35). If the answer is negative (NO), it is determined whether the flag FB is set to "1" (step S36). In the first loop, FB = 0 remains set (see step S21), and the process proceeds to step S37, where the control valve 43 is opened to start supplying air from the accumulator 39 to the air supply passage 36, and then to the second Is set to a predetermined time T2, and the second timer tmTV is started (step S38). Here, the predetermined time T2 is set to a time (for example, 200 ms) required for the actual line pressure PL to reach the starting pressure PLST after replenishment from the accumulator 39. And then the flag F
B is set to "1" (step S39), and after confirming that the second timer tmTV has become "0" (step S39).
40) Return to step S34.

Then, at step S35, PL ≧ PLST
Is determined, if the answer is negative (NO), the flag FB has already been set to FB = 1 in step S39, and the process proceeds to step S41 to proceed to step S41.
3 is closed, the third display lamp 19 is turned on, the driver is informed that the actual line pressure PL has not reached the starting pressure PLST (step S42), and the program ends.

On the other hand, if the answer in step S35 is affirmative (YE
In the case of S), the process proceeds to step S43 to determine whether or not the flag FB is set to "1". When the first loop is executed, the answer to step S35 is affirmative (YE
When S) is reached, since FB = 0 remains set, the flow advances to step S44 to enable connection of the starter circuit and to turn on the second display lamp 18 to indicate that the engine can be started. Inform others. On the other hand, when the answer to step S35 is affirmative (YES) after the flow of steps S36 to S40, since FB = 1 is set (see step S39), after closing the control valve 43 (step S45), The second display lamp 18 is turned on (step S44), and then the third timer tmTS is set to the predetermined time T.
3 and start the third timer tmTS (step S46). Here, the predetermined time T3 is set to a time (for example, 30 s) until the line pressure PL decreases due to air leak or the like and the engine cannot be started.

Next, in step S47, it is determined whether or not the starter switch 16 has been switched to the ON state. If the answer is negative (NO), the third timer tmT
It is determined whether or not S has become "0" (step S4).
8).

If the answer is negative (NO), the process returns to step S47 to determine whether or not the starter switch has been switched to the ON state, and the answer is affirmative (YES).
In step S49, the process proceeds to step S49, where the engine speed NE is detected, and it is further determined whether or not the engine speed NE has reached a predetermined speed NEX (for example, 100 rpm) required for a complete explosion (step S50). , The answer is affirmative (YE
In the case of S), it is determined that the start of the engine has been started, and the program ends.

On the other hand, step S47 or step S50
If the answer is negative (NO) and the third timer tmTS times out in step S48, the starter circuit is shut off (step S51), the second display lamp 18 is turned off (step S52), and the program ends. I do. That is, the start of the engine is started when the starter switch 16 is switched to the ON state and the engine speed NE reaches the predetermined speed NEX before the time of the third timer tmTS expires, while the third timer tmTS If the starter switch 16 is in the OFF state or the engine speed NE does not reach the predetermined speed NEX even if the time is up, the starter circuit is cut off to prohibit the start of the engine.

It is needless to say that the present invention is not limited to the above embodiment, but can be changed without departing from the scope of the invention. For example, in the above embodiment, the air pump 4
1 supplies air to the accumulator 39,
As shown in FIG. 9, in an internal combustion engine with a supercharger in which a supercharger 46 such as a turbocharger or a supercharger is interposed in the intake pipe 2 and the exhaust pipe 45 to increase the output of the engine, A branch pipe 48 communicating with the accumulator 39 via the check valve 47 is provided between the supercharger 46 and the throttle valve 3 ′ so that the air pressure from the supercharger 46 is supplied to the accumulator 39. preferable.
That is, in this case, during the operation of the engine, the supercharger 46 is driven by the exhaust gas flowing through the exhaust pipe 45 to supply air to the intake pipe 2, and the supplied air is supplied to the accumulator 39 so that the air pump 41 can be used less frequently, and power can be saved. In addition, even when the engine is started, if the air having the predetermined air pressure is filled in the accumulator 39 by the air supply to the accumulator 39 in the previous operation of the engine, the operation of the air pump 41 can be omitted, thereby saving power. be able to.

[0061]

As described above in detail, the present invention relates to an air pressure supply source, an air chamber to which air pressure for urging an intake valve and an exhaust valve in a valve closing direction is provided, the air chamber and the air pressure supply. An air supply passage communicating with a source, and a pressure of the air supply passage.
Pressure detecting means for detecting, and interposed in the middle of the air supply path
Control valve and the engine including at least the engine speed.
Operating state detecting means for detecting an operating state of the gin;
Based on the engine speed detected by the state detection means
Target pressure calculating means for calculating a target pressure value by
The pressure detected by the detecting means is at least the target pressure.
To reach the target pressure value calculated by the force calculation means.
An air spring type valve train for an internal combustion engine, comprising: an air pressure control means for controlling the control valve.
Even if the control valve is controlled by the means, the pressure detection means
If the detected pressure does not reach the target pressure, the pressure
Operating condition of the engine according to the pressure detected by the
Operating state control means for controlling the state of the engine, so that even if air leaks occur from the seal portion of the valve train during operation of the engine, the actual pressure in the air supply path is controlled to maintain at least the target pressure value. The air chamber is replenished with desired air, it is possible to ensure the sealing performance when the intake and exhaust valves are closed , and the air is supplied from the air supply source under pressure.
Even when air pressure is low,
Controlling the operating conditions of the gin can damage the engine
Insufficient air volume
In this case, the security function can be secured.

[0062]

Further, when the operating state of the engine is controlled by the operating state control means, there is provided a display means for displaying that the pressure of the air supply passage has not reached the target pressure. Can quickly know the pressure drop in the air supply path, and can quickly respond to the pressure drop in the air supply path.

[0064]

[0065]

[0066]

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an air spring type valve train for an internal combustion engine according to the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the internal combustion engine.

FIG. 3 is a configuration diagram schematically showing a valve train control unit.

FIG. 4 is a flowchart illustrating a control procedure of a valve train control unit during engine operation.

FIG. 5 is a PLTAG map diagram.

FIG. 6 is a NELMT map diagram.

FIG. 7 is a flowchart (1/2) illustrating a control procedure of a valve train control unit when the engine is started.

FIG. 8 is a flowchart (2/2) showing a control procedure of a valve train control unit when the engine is started.

FIG. 9 is a main part configuration diagram of a valve train control unit according to another embodiment.

FIG. 10 is a longitudinal sectional view of a main part of a conventional valve train.

[Explanation of symbols]

1 an internal combustion engine 5 ECU (target pressure calculating means, pneumatic control means, operating state control hand stage) 11 NE sensor (operating condition-detecting means) 17 first indication lamp (display means) 18 second indication lamp (display means) 19 Third display lamp (display means) 26a Intake valve 26b Exhaust valve 34a, 34b Air chamber 36 Air supply path 39 Accumulator (air supply source) 42 PL sensor (pressure detection means) 43 Control valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-230910 (JP, A) JP-A-2-230909 (JP, A) Japanese Utility Model 63-14808 (JP, U) Japanese Utility Model 63 63512 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F01L 3/10 F01L 1/14 F01L 9/02 F02D 11/08 F02D 13/02

Claims (2)

(57) [Claims] 1. An air pressure supply source, an air chamber supplied with air pressure for urging an intake valve and an exhaust valve in a valve closing direction,
An air supply path that communicates the air chamber with the air pressure supply source, a pressure detection unit that detects a pressure of the air supply path,
A control valve interposed in the middle of the air supply path, at least
Also detects the operating state of the engine, including the engine speed
Operating state detecting means; and
To calculate the target pressure value based on the engine speed
The target pressure calculation means and the pressure detected by the pressure detection means
Pressure is calculated by at least the target pressure calculating means.
Air for controlling the control valve to reach the set target pressure value
And a pressure control means for controlling the control valve by the air pressure control means.
If the pressure detected by the detection means does not reach the target pressure
When the pressure is detected by the pressure detecting means.
An air spring type valve train for an internal combustion engine, comprising operating state control means for controlling an operating state of the engine. And a display means for displaying that the pressure of the air supply passage has not reached a target pressure when the operation state of the engine is controlled by the operation state control means. An air spring type valve train for an internal combustion engine according to claim 1 .