JPS60140128A - Internal combustion engine - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid-cooled dynamic piston internal combustion engine which is provided with a detection device for generating a signal indicative of the operating conditions within the combustion chamber of the engine.

BACKGROUND OF THE INVENTION In spark ignition engines, detection devices are known as "knock sensors" and are used to detect the occurrence of detonation of the air-fuel mixture within the combustion chamber of the engine. The signal obtained from the detection device is used to control the ignition timing so that the ignition timing is retarded if detonation begins to occur. Preventing detonation is particularly important in spark ignition engines since spark ignition engines are not designed to withstand the very high pressures or sudden pressure increases that occur when detonation occurs. In the case of a compression ignition engine, the situation is somewhat different because detonation of the air-fuel mixture occurs frequently even during normal operation of the engine, and the engine is designed to withstand the high pressure and rapid pressure rise that occurs. However, the detection device provides useful information such as the start of combustion of fuel, which is used to adjust the fuel injection timing.

Two types of detection devices are known, one of which consists of a device that is in direct communication with the cylinder or combustion space. Since such devices only provide a signal for a particular cylinder or combustion chamber, if it is necessary to monitor each cylinder or combustion chamber of the engine, it is necessary to install as many devices as there are cylinders or combustion chambers in the engine. J has to be.

Furthermore, since the device is in direct communication with the cylinder, it is exposed to severe moving conditions within the cylinder. Also, such equipment should be removed [
] requires machining the hole into which the device is mounted.

Other types of devices detect combustion conditions indirectly;
The disadvantage is that the signal/noise ratio is poor because the impact, bearing noise, and piston slump when closing the valve tend to be widespread. Such devices are mounted on the cylinder head of the engine, for example on the outer wall of the cylinder head. In an attempt to improve the performance of such devices, European Published Application No. 0079042 discloses that the device is mounted on a boss formed in the inner wall portion of the engine block and passing through the outer wall portion having a water cavity and an aligned frontage. It is known that the device has a seal that is screwed into the boss and engages the outer wall to prevent water from leaking.The device is sensitive to the conditions of the particular cylinder with which it interacts , usually does not react to the status of other cylinders.

The present invention relates to a second type of detector and aims to provide an engine of the above type in a simple and convenient form.

Means for Solving the Problems According to the invention, in an engine of the type described above, the device is connected to a tie flam, to means for supporting the die flam in the wall of the engine, and to a diaphragm for generating noise. Means for providing an electrical signal is provided, and the inner surface of the wall defines a cooling fluid cavity such that one side of the diaphragm is in contact with the cooling fluid, which transmits combustion noise from the combustion chamber of the engine to the diaphragm 17.

Further, according to the invention, the die 17 phragm is installed in the core opening of the cylinder head of the engine.

Also in accordance with the present invention, the system is made more sensitive to combustion noise by tuning the die 47 flam to the main vibrations of the combustion chamber.

Operation Referring to FIG. 8, the engine is mounted on a cylinder block 1 on which a cylinder head 2 is mounted.

A cylinder 3 in the block houses a piston 4 which is connected to the engine crankshaft in the usual manner.

The cylinder head defines a combustion space 5 in which fuel is combusted. A cooling fluid cavity 6 is provided in the cylinder block.
A cavity 7 is provided in the cylinder head like b In1. Even if the cavity 7 is a single cavity extending in the longitudinal direction of the cylinder head, it may be a single cavity extending in the longitudinal direction of the cylinder head.
It may also be a series of interconnected cavities. A frontage 11 is installed in the outer wall 10 of the cavity 7 for cold liquid in the cylinder head, which is conveniently drilled so that the cylinder head II dipping plate is inserted through U1. There is C.

When in use, the coolant contacts the wall at 12-4. In conventional constructions, the opening 11 is closed by a so-called core plug, which conveniently consists of a disc-shaped material which can be placed within the opening and is deformed to settle within the opening. A detection device consisting of a dyed hair 7 frame 13 with the hem 1/I aligned to the right is pushed into the opening and forms a liquid-tight seal with the wall surface thereof. An adhesive-containing filler may be used to hold the diaphragm in place. The die 17 flam is made of a corrosion-resistant material, such as metal,
It is made of ceramic, hydrocarbon plastic, silicone elastic material, etc.

Die 17 flam has piezoelectric type, piezoresistive type, Hakuhizumi 5
A detection element 15 of any suitable type is fixed. The thickness and shape of the dilenorum are adjusted to have a natural resonant frequency that matches as closely as possible the natural frequency of the main resonant sound of the combustion space. In diesel engines, the hole diameter is 10
In a 0 mm engine, the main resonance occurs at 5 k t-1z, and as the cylinder bore becomes smaller, the frequency becomes higher. 76
In a spark-ignition Kallin engine with a mm hole, the natural frequency of this resonance rises to 6.5 kHz. Particularly in doll engines where the combustion chamber is hemispherical, the dominant acoustic mode has a wavelength equal to twice the diameter of the combustion chamber. In engines using a prechamber, the prechamber acts as a Helmboltz resonator due to the gas in the main chamber, providing excess stiffness. Although 51 nodes of these natural frequencies are possible, it is complicated, so it is preferable to confirm it by experiment.

Embodiment Due to the configuration of the device shown in FIG. 1, the detection cord 15 is limited to one that can withstand the deflection of the die 17 flam when the device is placed in the opening. Furthermore, if the diaphragm is roughened during assembly, the natural frequency will rise. One way to overcome this difficulty is to use the configuration of FIG. 2, in which the diaphragm is initially provided with a roughened portion 1G. In this case, piezoelectric and ramic sensing elements are
It is held in place by a light coil spring 18, which is fitted to the countersunk portion of the flam. ] The spring is the movement of the electrical connection to the element. As shown in FIG. 2, the spring engages an insulated base member 19 with an electrical connection to the spring at 8'. Before the ceramic elements are placed in place, a conductive adhesive that cures above 50° C. is placed on the countersunk of the die 17 noram. The adhesive is also such that it absorbs distortions that occur when the diaphragm is assembled into the opening 11. When the engine is running, the temperature of the coolant increases, causing the adhesive to harden. As a result, the ceramic element is not subjected to large stresses caused by assembly.

FIG. 3 shows an alternative arrangement which is separated from the flange 14 by a convolution 21 which ensures that the tire flamm 20 rests without any significant stress when the device is inserted into the opening. In this case, the ceramic element 17 is assembled and fixed to the front diaphragm. In the configuration of FIGS. 2 and 3, a cover 22 is provided which carries an electrical connector 23 for making electrical connections to external devices. However, it is also possible to accommodate the preamplifier on the underside of the cover. The preamplifier has a low output impedance so that connections to external devices pass through and pickup from electrostatic and electromagnetic fields is minimized. Preferably, the preamplifier performs band P-wave.

Another embodiment is shown in FIGS. 4 and 5. In Figure 4,
The skirt portion 14 is not used for sealing, but is provided with an annular outwardly extending flange 24 which is fixed to the outer wall surface of the cylinder head with a suitable fastener. 25 is provided at the connection between the hem and the flange to prevent cooling fluid from forming.

In the configuration shown in FIG. 5, the diaphragm 26 has an annular elastic mounting portion U that does not transmit to the diaphragm even the smallest deflection of the base member 27 when pushed into position in the opening [1].
28 to the cup-shaped base member 27.

Shown in Figure 6-! l'17. In the construction, the die 17 flamm 29 is supported against the plate 30 by a ring ring made of piezoelectric wire 1, which in this embodiment consists of two rings 31 and 32 made of keratin. The surface of the ring 31 is the receiving plate 30
The opposite side of the ring 32 is electrically connected to a die hair frame which is centrally connected to the receiving plate by a central screw 33. A central annular collecting member 34 is interposed between two rings that are polarized such that, upon compression, both rings 34 generate a usable signal.

Jl of the diaphragm [[and for buffering, rings 31 and 3
An annular gasket 35 is interposed between 2 and the hem of the receiving plate 30. In the modified row shown in FIG. 7, the diaphragm 36 is cup-shaped with a skirt 37 terminating without reaching the bottom wall of the receiving plate 30; in this case the sealing is effected by an annular gasket 31A. However, if desired, the die 87 flam can be convoluted, as in the example of FIG.
The peripheral edge of the flamm may be fixed directly to the hem of the base member.

The sensing element can also be formed from a semiconductor material attached to the diaphragm. Such materials provide a large output signal 1 but have the disadvantage that the output varies with temperature. This is reduced by supplying current to the sensing element through the collector-emitter path of a transistor whose base is fixed at a constant potential.

The transistor is housed next to the device, and is made of the same material as the device, or the transistor's parameters r depending on temperature changes.
Conveniently, it is made of a material that compensates for changes in the gauge factor of the semiconductor device as a function of temperature due to changes in VbeJ. An amplification stage with an input impedance of at least 100 times the resistance of the element by means of a capacitor may be provided in close proximity to the element.

The value of the capacitor I and the input impedance can be selected to allow the high pass filter to reject low frequency signals that would overload the amplifier stage.

[Brief explanation of drawings]

Figures 1 to 7 show an example of a detection device according to the present invention, which is inserted into the wall of the coolant cavity of the engine, and Figure 8 is a partial cross-sectional view of the engine. Yes. 1... Cylinder block, 2... Cylinder head,
3... Cylinder, 4... Bis], 5... Combustion space, 6... Coolant cavity, 7... Cavity, 10...
・Outer wall, 11...opening, 13, 20, 26, 29.3
6...Die 1 flam, 14.37...Hem part, 15.
. . . Detection element, 16 .・・・
・Electrical connector, 24...flange, 25...sealing ring, 28...mounting part, 30...receiving plate, 31
．． 32...Ring, 31△...Gasket, 33...
Screw, 3/I...] Relefting Department Month 35...Gasgutsu 1~.

Claims (1)

[Scope of Claims] (1) Consisting of a diaphragm, means for supporting the diaphragm within a wall of the engine, and means connected to the diaphragm for generating an electrical signal representative of noise, the inner surface of the wall being connected to the diaphragm. A coolant cavity is defined so that one side is in contact with the coolant, and the coolant liquid transmits combustion noise from the combustion chamber of the engine to the diaphragm, and represents the operating state in the combustion chamber of the engine. A liquid-cooled dynamic piston internal combustion engine equipped with a detection device that instantly generates a signal. ■ The Daihiki 7 Noram is characterized by being attached to the core opening of the cylinder head of a single engine! An internal combustion engine according to claim 1. (J) The internal combustion engine according to claim 1 or 2, characterized in that the diaphragm is tuned to the main resonance sound of the combustion chamber. (4) The diaphragm is press-fitted into the opening. An internal combustion engine according to claim 1, characterized in that it has a liquid-tight seal and has an integral skirt. 6) An internal combustion engine as claimed in claim 4, characterized in that it has a sensing element fixed to the diaphragm. Internal combustion engine as described in section. 6) The diaphragm has a contoured shape, and the sensing element is provided in the contoured portion of the diaphragm, and the sensing element is inserted into the contoured portion of the diaphragm by means of an adhesive having a curing temperature such that it hardens only during the first operation of the engine. The die A7 flam on the internal combustion side according to claim 5, wherein the die A7 flam is moved so as not to transmit stress generated when the detection device is inserted into the opening to the die A7 flam. 6. The internal combustion engine according to claim 5, wherein the internal combustion engine is connected to the skirt portion by a convoluted portion. ■ The detection device includes a cup-shaped receiving plate whose hem is fixed in the frontage, a diaphragm made of a disk, and a screw connecting the center of the diaphragm to the center of the cup-shaped member.
It consists of an annular detection element interposed between the diaphragm and the bottom wall of the holder, and means for buffering the movement of the diaphragm by forming a stop between the periphery of the diaphragm and the holder. An internal combustion engine according to claim 1, characterized in that: (9) The annular detection element consists of a pair of pyramid material rings installed on both sides of an annular lefting member,
When the ring is in motion, both rings are rectified.
9. The internal combustion engine according to claim 8, wherein the output signal valve 4V is polarized so that J>LJ is polarized in the ring member. (10) The die round 7 flam has a cup shape having an outwardly extending flange that is fixed to the outer wall of the engine around the spacer L1. institution.