JPS6217116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine diagnostic device, and more particularly, to an engine diagnostic device.
The present invention relates to a device for monitoring events within a combustion chamber of an internal combustion engine by means of microwave energy injected into the combustion chamber. More particularly, the invention provides:
It involves an adapter for coupling both microwave and ignition energy through an engine spark plug, through gasoline, and into the combustion chamber of a gasoline engine.

Up to now, it has been proposed to inject microwave energy into the combustion chamber of a gasoline engine and monitor the microwave signal to determine and diagnose timing in the engine. U.S. Pat. Nos. 3,589,177 and 3,703,825 to Merlo disclose an adapter for coupling both microwave and ignition energy through an engine spark plug to the combustion chamber of a gasoline engine. Merlo's adapter includes a waveguide and a coaxial transmission line having a generally T-shaped configuration and extending laterally through the waveguide to the spark plug. Ignition energy is transferred to the spark plug by the center conductor of the adapter's coaxial transmission section, which extends laterally through the waveguide and is surrounded by insulation. Microwave energy transmitted through the waveguide is coupled through the dielectric to the center conductor and thereby through the spark plug conduit and ignition electrode to the combustion chamber.

Spark plugs, which have become particularly widely used in recent years, are designed to electrically connect the spark plug input terminal from the ignition electrode to the spark plug lead wire in such a way as to prevent the passage of radio frequency noise in the opposite direction from the ignition electrode to the spark plug lead wire. It includes sections of high-resistance material (possibly fire-resistant material) that are separated from each other. A significant drawback of the Merlo spark plug adapter previously described is that Merlo's adapter relies on the so-called coaxial TEM transmission mode for the transmission of microwave energy from its input terminal to the electrode through the spark plug conduit. Because of this, the operating efficiency of conventional spark plugs is extremely low, as can be said of all conventional spark plugs. An important object of the present invention is to provide microwave power through the spark plug to the engine combustion chamber without relying on spark plug terminals or conductive paths, thus avoiding the problems associated with high resistance material sections in conventional spark plugs discussed above. To provide an adapter for connecting energy.

Further objects, features and advantages of the invention will become more clearly understood from the claims and the following description taken in conjunction with the accompanying drawings.

Now, referring to Fig. 1, a conventional spark plug 1
0 includes a metal shell 12 which is screwably adapted at one end 13 into an opening in an engine block 14 within the engine combustion chamber. A ceramic insulating housing 18 is carried by the outer shell 12 and surrounds the segmented spark plug electrode conductor 20. A section 22 of high resistance material, such as a refractory metal, is provided in series with the section of electrode conductor 20 to suppress radio frequency emissions as previously discussed. A spark plug input terminal 24 projects axially from the insulating housing 18 and is adapted to be connected to a spark plug lead from a power distributor or the like (not shown) for supplying ignition energy to the ignition electrode 16. ing.

A spark plug adapter according to the invention as illustrated in FIGS. 1 and 2 includes a spark plug insulating housing 18 at one end with a spark plug lead wire 26 removed therefrom.
It includes a cylindrical sleeve 28 having an opening 30 adapted to be received thereon. Most preferably, the cavity 30 is internally configured to complement the contours of the spark plug insulating housing and the terminal 24 and is configured on the insulating housing to facilitate transfer of microwave energy from the sleeve to the housing. It is something that should be properly accepted. The annular edge 32 within the cavity 30
8 is adapted to be punched and received by a snap fit into a corresponding recess on the spark plug terminal to ensure secure installation on the spark plug. Sleeve 28 is preferably constructed of polytetrafluoroethylene, known under the trade name "Teflon," or other resiliently flexible insulating material. Connector 34 rests on the end of sleeve 28 remote from cavity 30 and has a tapered neck 38 extending into and being supported in a corresponding opening 39 in sleeve 28. It includes an insulator 36 made of or the like. Electrical conductor 40 extends through insulator 36 and
The sleeve 28 is connected to the plug terminal 24 by the air gap 44.
The spark plug terminates at 42 within the sleeve 28 in a position adapted to be received on a conventionally sized spark plug such that it is axially separated or spaced from the spark plug. A conductor 40 having an insulator 36 on the outside
The ignition energy passes from the cable 26 through the conductor 40, across the air gap 44, and into the spark plug 10.
The spark plug cable 26 terminates in a terminal 46 adapted to removably receive the spark plug cable 26 for communication through the spark plug cable 26 into the combustion chamber.

A microwave antenna 48 is mounted externally to the sleeve 28 near its open end and is connected to the spark plug 10.
The antenna is adapted to be extendable and retractable above so that the antenna is positioned radially adjacent the spark plug insulating housing 18 in assembled condition with the spark plug. The antenna 48 has two adjacent sides 5
0,52 consists of the central conductor 54 of the section of coaxial cable 56, and the opposite adjacent sides 58,
On 60 the cable ground conductor or shield 6
1, the central conductor and shield of which are electrically connected at the free ends of the loop sides 50,60. The loop antenna 48 is connected to the sleeve 28 by resting or being embedded in the outer sleeve surface of the loop antenna 48 with one side 50 in an orientation parallel to the axis of the sleeve 28 and thus parallel to the axis of the spark plug 10. so that loop 48 is effectively disposed in a plane parallel to the sleeve and spark plug axis. Leaving the antenna 48, the coaxial cable 56 transmits microwave energy through a coaxial adapter 64, such as the Heuretz Packard Coaxial Adapter, Model X281A, to a Microwave Associates "Gunplexer", Model MA-87141-1. The microwave transceiver 62 is connected to a microwave transceiver 62 as a source. Adapter 64 is connected to transceiver 62 by a sheet 68 of insulating material such as cellophane.
insulated from The seat 68 is the plug 10
The waveguide cavity 70 in the adapter 64 extends across the waveguide cavity 70 and the transceiver 62 to block the DC high energy signals induced in the loop 48 by the ignition signal. The adapter 64 is attached to the transceiver 62 using insulating screws 72 made of, for example, nylon.
The input and output terminals of transceiver 62, which includes a microwave source and detection means, are coupled to engine diagnostic circuitry 66, an example of which is shown in the aforementioned Merlo patent.

In operation, microwave energy is injected from the antenna 48 through the sleeve 28 and the spark plug insulation housing 18 into the engine combustion chamber, so that the high resistance exhibited in the spark plug section 22 is effectively avoided. In other words, and still in accordance with an important and distinctive feature of the invention in its broadest aspect, the insulating sleeve 28 and the spark plug insulating housing 18 substantially avoid the spark plug conduit and ignition electrode thereof. They cooperate for the direct transmission or coupling of microwave energy to the engine cylinders. That is, the spark plug conduit does not play a substantial role in transmitting microwave energy to the engine cylinder. Thus, the adapter of the present invention operates in the so-called waveguide transmission mode, which is different from the so-called coaxial TEM transmission mode characteristic of the prior art by Merlo, and thereby overcomes the difficulties encountered in the prior art. Avoiding.

Transfer of microwave energy to spark plug lead 26 is effectively inhibited by air gap 44 . In one mode of operation of the invention, where the microwave frequency is 10 GHz, the air gap 44 is
The axial dimensions range from 0.025 to 0.25 inches (0.63 to 6.33 mm), preferably on the order of 0.05 inches (1.27 mm). Preferably, the circumference of loop antenna 48 is equal to one wavelength of the selected microwave frequency, but at present, such circumference is the first
It is unclear whether this is critical to the operation of the embodiment of FIG. Generally, loop 48 is coplanar with the coincident axes of sleeve 28 and spark plug 10, as best seen in FIG. A particular advantage of the rectangular loop configuration shown in FIGS. 1 and 2 is that the rectangular loop configuration shown in phantom in FIG. The surface of such a loop can be manually adjusted angularly with respect to its sleeve and spark plug axis, as shown in FIG.

The embodiments of the invention hitherto described are particularly useful for microwave analysis of engine operation in use, with the engine already installed in a motor vehicle. In such circumstances, the normal spark plug lead for the selected cylinder is removed from the spark plug in which it is installed;
The sleeve 28 is attached to the spark plug in question as described above. The resiliency of sleeve 28 facilitates installation and removal of the adapter. Thereafter, when the lead wire 26 is connected to the adapter terminal 46, the engine thereon will be operated without any noticeable effects due to the microwave diagnostic device and the adapter. Under some circumstances, the adapter may have its own spark plug received within the sleeve 28, thus
In the test condition, the engine spark plug will be removed and replaced with an adapter with a test spark plug. Under some circumstances, a short sleeve 2 of sufficient length to exclude the adapter connector 34 and mount the antenna 48 on the spark plug insulation housing 18 may be used.
It is also possible to give 8. For such a modification, spark plug lead 26 would be connected directly to spark plug terminal 24.

3-5 illustrate a modified spark plug adapter embodying the principles of the present invention.
The adapter 100 of FIG. 3 is a so-called cold adapter used where ignition energy is not supplied to a cylinder during testing. The adapter 100 is
It includes a hollow interior threaded metal tube 102 having a plug 104 of insulating material threadably received at one end. Plug 104 has an internal cavity 106 that is contoured to snugly receive at least the insulating housing 18 of spark plug 10. A microwave tuning device 108 is threadably received at opposite ends of tube 102 and extends longitudinally therethrough parallel to, but laterally offset from, the axis of core 109 and tube 102. It includes a metal core 109 with an extending passageway 110. Insulated conductor 11
2 is received within the passageway 110 and projects from the core 109 into the interior of the tube 102 within the space or cavity between the core 109 and the plug 104 to form a linear microwave antenna 114. Conductor 112 is connected within core 109 to receive microwave energy from a microwave source such as that shown in FIG.
It is connected to a coaxial conductor 118 through a lateral passageway 116. The notched thin nut 120 is the core 10
9 and a handle 122 is integrally formed with its core.

A second modified adapter 130, shown in FIGS. 4 and 5, applies ignition energy to the spark plug under test as in the previously described embodiments of FIGS. 1 and 2. It is adapted for so-called heating operations in places. adapter 130
In , a hollow sleeve or plug 132 of insulating material is threadably received into one end of a metal tube 134 and is internally formed into a cavity 136 to properly receive a spark plug insulating housing as previously described. is outlined. Tuning device 138 includes a metal core 140 that is screwed into tube 132. An insulated conductor 142 extends from the coaxial connector 144 through a passageway 146 in the core 140 and
0 and plug 134 in a generally square three-sided open loop antenna 148 in the cavity within tube 132 . The plane of antenna 148 is tangential to the axis of adapter 130. A thin nut 150 is screwed into the core 140. Ignition energy is received on the spark plug terminal from a terminal 152 on the core 140 adapted to be connected to the spark plug wire (FIG. 1) through sliding telescoping brass conductors 154, 156. A cap 158 is supplied to the cap 158. Conductor 154 is carried within core 140 by sliding insulating elements 160,162.

In each of the modification examples in FIGS. 3 to 5,
Microwave energy is transmitted to the antenna (114 in FIG. 3,
and 148 in FIG. 5) through space and through a plug of insulating material (104 in FIG. 3 and 134 in FIG. 4) to its spark plug insulating housing. That energy then
It is transmitted through its insulating housing to the cylinder under test, bypassing the spark plug conduit and electrodes. Thus, although the modified embodiment of FIGS. 3-5 differs from the embodiment of FIGS. 1 and 2 in details, the modified embodiment also utilizes the general principles of the invention. The microwave energy therein, in waveguide transmission mode, passes into and through the spark plug insulation housing and into its engine cylinder, substantially bypassing the conduit for the ignition energy. transmitted to. The details of the adapter shown in FIGS. 33-5 are not the subject of this application.

[Brief explanation of the drawing]

1 is a partially broken away and partially schematic cross-sectional view of a spark plug adapter according to the present invention; FIG. 2 is an end view of the adapter illustrated in FIG. 1, and in particular: 3 and 4 are cross-sectional views of a modified spark plug adapter embodying the principles of the present invention; and FIG. , a cutaway cross-sectional view taken along line 5--5 in FIG. 4; 10: Conventional spark plug, 12: Metal outer shell, 1
4: Engine block, 16: Ignition electrode, 1
8: Insulating housing, 20: Electrode conductor, 22: Section of high resistance material, 24: Spark plug input terminal, 2
6: Spark plug lead wire, 28: Cylindrical sleeve, 30: Cavity, 32: Edge of cavity, 34: Connector, 36: Insulator, 38: Tapered neck, 3
9: opening, 40: electrical conductor, 42: terminal end, 4
4: air gap, 46: terminal, 48: antenna, 50,
52: Side part, 54: Center conductor, 56: Coaxial cable, 58, 60: Side part, 61: Shield, 62:
Transceiver, 64: Adapter, 66: Engine diagnostic circuit device, 68: Sheet, 70: Waveguide cavity, 72: Screw.

Claims (1)

[Claims] 1. Insulating housing 18 and ignition conduit passages 20, 22
an adapter for coupling microwave energy to a combustion chamber of an internal combustion engine through a spark plug 10 of the type including a spark plug 10 configured to removably receive the spark plug insulating housing 18 and having a cavity 30 at one end; , 106, 136; 102, 104; 13;
2, 134, coupled to the sleeve and the microwave energy source 62, and in a waveguide transmission mode, through the sleeve and the spark plug insulating housing to the combustion chamber independently of the conduit passages 20, 22. microwave antenna 48, 114, for transmitting microwave energy;
An adapter consisting of 148. 2 The spark plug 10 is connected to the spark plug lead wire 2
6 having a terminal 24 extending axially from said housing 18 for connection to said housing 18 for coupling both microwave energy and ignition energy to the fuel chamber of an internal combustion engine. The adapter of claim 1, wherein the spark plug terminal 24 is configured to be located within the cavity and is carried by the sleeve and spaced from the one end of the sleeve. The sleeve is configured to removably receive the spark plug lead wire, and the sleeve is configured to removably receive the spark plug lead wire, and the sleeve is configured to removably receive the spark plug lead wire.
the cavity 30, 13 so as to be electrically connected to the terminals of the spark plug when received in the spark plug;
conductor 40 extending into 6; 152, 15;
Adapter including 4,156,158. 3. The spark plug 10 has an ignition electrode at one end that is configured to be screwed into the engine 14 so that the ignition electrode projects into the combustion chamber, and the spark plug 10 has an ignition electrode at one end that is configured to be screwed into the engine 14 so that the ignition electrode projects into the combustion chamber.
surrounds the insulating housing 18 such that the terminal 24 is disposed inside the sleeve;
3. The adapter of claim 2, wherein said microwave antenna (48, 114, 148) is carried externally of said sleeve and is configured to transmit microwave energy through said sleeve. 4 The microwave antenna is a loop antenna 4
Claim No. 8,148 consisting of
The adapter according to item 1, 2 or 3. 5. Adapter according to claim 4, wherein said antenna comprises a rectangular loop antenna 48 with one loop side arranged parallel to said axis. 6. The adapter of claim 5, wherein the plane of the antenna 48 is angularly adjustable with respect to the axis. 7. An adapter according to claim 5 or 6, wherein the rectangular loop antenna 48 has a loop size substantially equal to one wavelength of a selected microwave energy. 8. Said conductor 40, 42; 154 is separated from said spark plug terminal 24 by a high resistance air gap 44 so as to inhibit the transmission of microwave energy to said spark plug lead 26. The adapter according to item 2 or 3 of the range. 9. The adapter of claim 8, wherein the air gap comprises an air gap 44 between the conductor and the terminal of the spark plug, the size of which ranges from 0.025 to 0.25 inches (0.63 to 6.33 mm). . 10. The adapter of claim 9, wherein said dimension is substantially equal to 0.05 inches (1.27 mm). 11. The sleeve 28 is constructed of a resiliently flexible insulating material and is adapted to be received and retained over the spark plug insulating housing 18 and the terminal 24 by a snap fit. Adapter according to scope 1.