HK1064424A - Coil-on plug inductive sampling method and apparatus - Google Patents

Description

High-voltage coil type spark plug induction sampling method and device

CROSS-REFERENCE TO A CREAM APPLICATION

This application claims priority from U.S. provisional patent application No. 60/308,562, filed on 31/7/2001, the entire disclosure of which is incorporated herein by reference.

Technical Field

The present invention relates to an engine analyzer of a direct ignition system for an internal combustion engine including a coil-on plug ignition device (coil-on plug ignition) or a coil-on plug ignition device (coil-on plug ignition), and more particularly, to an engine analyzer employing an ignition signal pickup to detect an ignition waveform in a direct ignition system. The invention is particularly applicable to engine analysis of automobiles in which the secondary ignition waveform and the values of this waveform segment are displayed for evaluation by a technician.

Background

Engine analyzers provide a machine worker with a tool for accurately detecting the performance of an ignition system as a measure of the performance of the entire engine. Signal detectors ("test probes") are widely used for the detection of defects and anomalies in internal combustion engines. Test probes may be placed adjacent to test points, such as ignition coils or ignition leads, which feed signals back to the vehicle diagnostic test apparatus. Information obtained by the test probe, such as spark plug firing voltage and duration, helps a mechanic determine whether the spark plug associated with the ignition coil is functioning properly.

Fig.1a shows a system for detecting a capacitance signal. The ignition coil 110 is actually a transformer having a large turns ratio, and the turns ratio between the primary and secondary coils is generally 1: 50 to 1: 100. The transformer converts the low voltage of the primary winding into the high voltage of the secondary winding by abruptly changing the primary current. Ignition coil 110 is connected to the center of dispenser cap 114 or coil connector (not shown) by an insulated wire 112. The high voltage of the ignition coil 110 is distributed from the coil connections to the spark plug connections or sides of the distributor cap 114 via a rotor that distributes the spark to each spark plug connection at a predetermined timing in a manner known to those skilled in the art in standard technical manuals. The spark plug voltage is in turn provided by insulated wires 118 to the spark plug connectors and corresponding spark plugs 122.

In each cylinder, a spark is generated by an electrical discharge between the spark plug electrodes, thereby igniting a gas mixture that enters the cylinder and is compressed into an explosive state to drive a piston within the cylinder to power an associated crank. Ignition waveform analysis for determining engine performance may be performed by capacitively coupling a capacitance signal collector 124 to the spark plug wire 118. The capacitance signal collector 124 may conveniently wrap around or clamp the wire 118 at one end and connect to a measurement device 128 at the other end via a wire or a coaxial cable 126. The voltage on line 118 may be determined using the total capacitance measured by capacitance signal collector 124 in combination with a conventional capacitance divider circuit in a manner well known to those skilled in the art.

More recently, ignition systems have been developed with one coil per cylinder or one coil per pair of cylinders (direct ignition systems (DIS) or hybrid ignition systems) without any spark plug wire at all. Such spark ignition systems incorporate an ignition coil disposed above or proximate to each spark plug, as shown, for example, in fig.1 b. At the secondary coil 164, the high voltage generated by the primary coil 162 and the magnetic core 160 passes through the output of the secondary coil and is conducted through various conductor elements, such as from the spring 169 to a spark plug (not shown) housed within the spark plug cover 160. Igniter 168 is a switch that opens after current flows through the coil. This transient causes a larger voltage in the primary coil and is increased by the secondary coil switching.

Fig. 1c shows a coil-on-disc (COP) ignition device with an ignition coil 140, a spark plug 150 and a plug cover 151. This arrangement is not possible with the conventional technique of fig.1a described above, since the secondary high voltage conductors are not as readily accessible as the conductors 118 of fig.1 a. For this COP configuration, a high-voltage coil spark plug signal sensing device or sensor 141 similar to that taught in U.S. patent No. 6,396,277, owned by the assignee of the present invention and published on 2002, month 5 and 28, the contents of which are incorporated herein by reference, may be utilized. The COP sensor 141 includes upper and lower conductive layers (not shown) attached to and separated by a substrate 144. In one aspect, the upper and lower conductive layers serve as a signal detector and a ground layer. The upper layer is conductively connected to an external signal analysis device by conductive leads 152 and the ground layer reflects a portion of the electromagnetic energy generated by the coil, thus attenuating the signal strength observed at the signal detection layer to a level that is easily manipulated by a conventional analyzer. The sensor 141 is clamped to the housing of the ignition coil 140 by a clamp 147 attached to a sensor housing 148.

In this configuration, the sensor 141 is within the electromagnetic radiation field of the coil 140 when the coil converts the primary voltage to a high voltage for use by the spark plug. In operation, a low voltage and a high current are applied for a predetermined time to the primary winding of the ignition coil 140, which generates an electromagnetic field that is primarily a magnetic field (H). Because a high voltage and a low current are applied to the secondary winding, an electromagnetic field, which is mainly an electric field (E), is generated. The lower conductive layer is disposed adjacent to the outer shell of the coil 140 and is in fact connected to ground potential by such contact. The voltage potential may be positive or negative (typically negative for COP systems) and is induced or extended across the upper and lower layers 148, the surfaces of which or the signal detection layer may detect or receive. The voltage observed at the signal detection layer is proportional to the voltage at the terminal end of the secondary coil of coil 140. The signal detection obtained by the signal detection layer can be used in a manner known to the person skilled in the art for diagnosing ignition spark voltage characteristics such as spark voltage or burning time, or other problems like open conductor or spark plug wrap or short circuit.

No matter how great advantage the present high-voltage coil type spark plug signal detection device has, ignition coil's structure of all the difference makes any kind of sensor hardly generally applicable. For example, the sensor 141 is not ideal when the coil housing is shielded or otherwise configured to output a signal with significant distortion or attenuation. This occurs when the high-voltage coil-type spark plug device carries an igniter inside the iron shielding box, which shields the electric and magnetic fields of the iron core. Regardless of the configuration of such a shield itself, it is generally contemplated that the shield may include any medium or combination of media that substantially attenuates the output field of the coil-type spark plug assembly. Therefore, there is a need for a high-voltage coil type spark plug signal detection device that can be adapted to a low-output ignition coil structure.

Disclosure of Invention

In one aspect, a high-coil spark plug testing apparatus is provided for generating an output signal representative of an ignition signal. The test device includes an inductive sensor for sensing the electromagnetic flux generated by the high-voltage coil spark plug device during ignition and generating and outputting a corresponding voltage. The inductive sensor is coupled to the high voltage coil spark plug assembly. A signal processing circuit electrically connected to the inductive sensor generates an output signal responsive to changes in the output voltage of the inductive sensor.

In another aspect, a method for determining a burn time of a coil-on plug ignition device includes positioning an inductive sensor proximate to a housing of the coil-on plug ignition device, detecting an electromagnetic flux output by the coil-on plug ignition device using the inductive sensor during a process including at least one ignition phase, and determining the burn time. The burn time is determined by identifying an ignition line and identifying a spark line end, and determining the time between the ignition line and the spark line.

In another aspect, a method of detecting a problem with a high-coil spark plug ignition device includes positioning an inductive sensor adjacent a housing of a first high-coil spark plug, detecting electromagnetic flux output by the high-coil spark plug ignition device during a process including at least one ignition stage using the sensor, and identifying at least one of an ignition wire, a spark line, and a burn time. These steps are repeated for a second high voltage coil spark plug and at least one of the identified corresponding ignition wire, spark line and burn time are compared corresponding to the first and second high voltage coil spark plugs to determine a relative difference therebetween.

In another aspect, a method of detecting problems with a high-coil spark plug ignition device includes positioning a sensor adjacent a housing of a first high-coil spark plug, detecting electromagnetic radiation emitted by the high-coil spark plug ignition device during a process including at least one ignition stage using the sensor, and identifying at least one of an ignition wire, a spark line, and a burn time. These steps are repeated for a second high voltage coil spark plug and at least one of the identified corresponding ignition wire, spark line and burn time are compared corresponding to the first and second high voltage coil spark plugs to determine a relative difference therebetween.

Drawings

Fig.1a depicts a conventional capacitive sensor and circuit for detecting the secondary ignition voltage of a dispenser-based ignition system.

Fig.1b shows a COP ignition coil with an integrated igniter.

Figure 1c shows another COP capacitive sensor arranged close to the COP.

Fig.2a and 2b show a standard primary ignition waveform and a secondary ignition waveform, respectively, as displayed as a function of time.

Fig. 3 shows an inductive sensor and high-coil spark plug testing apparatus according to the present invention, in which the diode polarity is shown for positive polarity output.

Fig. 4a-4b show an inductive sensor and an RLC circuit, respectively, that may be used with an inductive sensor disposed directly above a high voltage coil spark plug.

Fig.5a is a waveform measured by a high-voltage coil spark plug inductive sensor connected to a display and a first circuit.

Fig.5b is a waveform measured by a high-coil spark plug inductive sensor connected to a display and a second circuit.

Fig. 6a-6b show test results for a high coil spark plug testing apparatus.

Fig. 7a-7b show test results of another high coil spark plug testing apparatus.

Fig. 8a-8b show test results of yet another high voltage coil spark plug testing apparatus.

Fig. 9a-9b show test results of yet another high voltage coil spark plug testing apparatus.

10a-10b show test results of another high voltage coil spark plug testing apparatus.

11a-11h show the results of testing the burn time for a dual induction sensor configuration.

Fig.12 a-12b illustrate the diagnostic efficacy of a dual inductor high voltage coil spark plug sensor.

Detailed Description

Fig.2a and 2b show a standard primary ignition waveform and a secondary ignition waveform, respectively, as displayed as a function of time. The waveform has three basic portions designated by an ignition phase, an intermediate phase and a dwell phase.

Common reference numerals used in fig.2a and 2b are used to denote common phenomena occurring in the primary and secondary waveforms. In the initial phase S of the waveform, no current passes in the primary ignition circuit. The voltage available at this point for the battery and charging device is generally in the range of about 12-15V, but is typically between 12-14V. At 210, the primary switching device switches on the primary current to initiate the "dwell" or "charge" phase. At 220, current is passed through the primary circuit, creating a magnetic field in the ignition coil winding. Thereby causing a rise in voltage along 230 indicating that the coil is saturated and the ignition system utilizes the coil saturation to control the coil current at which time current spikes and voltage fluctuations occur. The portion of the waveform representing the on-time of the primary current is between points 210 and 240. The signal section between points 210 and 240 thus represents the dwell phase or "on-time" of the ignition coil primary current as described above.

The primary switching device interrupts the primary current at 240, momentarily causing the magnetic field established to collapse and a high voltage to be induced in the primary winding by self-induction. Since the turn ratio between the primary winding and the secondary winding is 1: 50 to 1: 100, a higher voltage is induced in the secondary winding by mutual inductance. The secondary voltage is discharged to the spark plug gap, which is ionized, so that an arc across the electrodes generates a spark 250 (i.e., an "ignition wire") to initiate combustion, for a duration referred to as an "ignition phase" or "burn time" 260.

The ignition wire 250, in kilovolts, represents the amount of voltage required to generate a spark across the spark plug gap, typically between about 3-8 kV. The burn time 260 represents the duration of the spark process, typically about 1-3 milliseconds, and is inversely proportional to the ignition voltage kV. If the ignition voltage value increases, the combustion time decreases and vice versa. After the burn time 260 described above, the discharge voltage across the air gap between the spark plug electrodes drops and until the coil energy fails to sustain a spark between the electrodes (see 270). At 280, an oscillating or "ringing" voltage is generated and continues until 290, where the coil energy is dissipated, thereby causing no current to flow in the primary coil.

Fig. 3 illustrates a test setup for a high-coil spark plug for generating an output signal indicative of a characteristic of an ignition signal generated by the high-coil spark plug device. The high-voltage coil spark plug device includes an inductive sensor for detecting the ignition signal, means for coupling the inductive sensor to the high-voltage coil spark plug device, and a signal processing circuit for generating an output signal responsive to changes in the magnetic flux output of the high-voltage coil spark plug device.

The high-voltage coil-type spark plug inductive sensor 310 is disposed on the core 318 of the high-voltage coil-type spark plug coil, and the core 318 generates magnetic flux lines Φ 1. The magnetic flux lines Φ 2 pass through the inductive sensor 310 and in turn induce an electromotive force ∈ (not shown) in an N-turn coil (not shown) of the inductive sensor. The burn time of the spark plug can be determined by sampling the magnetic flux φ 2 generated by the inductive sensor 310 using the core of the high voltage coil spark plug device described above. Preferably, the inductive sensor 310 is in contact or adjacent to the high coil spark plug to maximize the amount of magnetic flux incident therefrom.

During testing, a technician may simply hold the inductive sensor in proximity to a high-coil spark plug (COP). However, it is generally preferred that the inductive sensor be disposed within a housing that may be positively connected to the housing of the high voltage coil spark plug or an adjacent engine component so that the technician's hands are eliminated and misalignment errors are minimized. The positive connection may be achieved by a securing means such as, but not limited to, a conventional clip or tie (tie down) configured to mate or connect with portions of the high coil spark plug housing, magnetic clip or threaded segment, so long as the means are available external to the high coil spark plug housing. In one aspect, the inductive sensor 310 may be biased relative to the housing of the coil-on-plug using one or more springs or a biasing element such as a foam insert. And the inductive sensor housing may be configured to mate with a dedicated high-coil spark plug housing. Alternatively, the inductive sensor housing may be configured as a plurality of individual inductive sensors and simultaneously mated to a corresponding plurality of housings of the coil spark plugs. Alternatively, inductive sensors may be integrated into the COP housing and connected via the vehicle wiring harness and data link to an on-board diagnostic data computer and/or data storage device for later use by a technician or for displaying appropriate information or signals to the vehicle operator.

The inductive sensor 310 is preferably an air-core inductor or open-core inductor, such as a "choke" inductor, typically designed as a filter for a switched-mode DC power supply. Such an inductor is integrated into a housing or circuit board having a geometry suitable for attachment to or placement adjacent a high-tension coil spark plug at the proximal end for ease of measurement. Closed core designs are generally not suitable for use in the present invention because conventional closed core designs substantially limit the magnetic flux through the core, and no external flux sampling is possible, which is essential to the present invention. Fig. 3 shows an example in which the shaft 312 has a core 313 of length L around which a winding 314 with N turns is arranged. The bobbin 312 may be composed of a non-magnetic material (e.g., plastic, cardboard, ceramic, wood, etc.) for merely maintaining the shape of the coil 314, or may include a ferrite or ferrite core.

The advantage of selecting inductive sensor 310 is that it can select the maximum self-inductance and self-vibration frequency, select the minimum coil impedance and size, and prevent the geometry of locating it on top of a high-coil spark plug without significantly disturbing the engine components of existing vehicles. Those skilled in the art will appreciate that the sensor 310 induction coil can be tailored to a particular application by varying the inductance (number of turns N), coil diameter, coil length, and coil material. For example, the magnetic field leakage is proportional to the square of the number of turns N. Similarly, other components of the RLC circuit 302, as shown in fig. 3, may also be adjusted in a manner well known to those skilled in the art.

In fig. 3, the inductive sensor 310 is placed directly above a high voltage coil spark plug 316 (cleusler P/N56028138), such as is used on more recent vehicle models of the guillain, daclata, and Durango jeep. Those skilled in the art will appreciate that the RLC circuit 302 is suitable for use in the aforementioned configuration of a jeep high-voltage coil-type spark plug 316 and is connected in parallel to the leads of the inductive sensor 310. As shown, the RLC circuit may include a schottky diode 330, a capacitor 332, a capacitor 334 and a resistor 336, and the capacitors 332, 334 may be readily replaced by a single capacitor in a manner known to those skilled in the art. Of course, some or all of these components may be omitted.

Inductive sensor 310 or element L1 may be a 470 μ H sensor, part number 03316P-474, manufactured by Coilcraft corporation of Cary, Illinois. The schottky diode 330 may be a standard semiconductor surface mount schottky rectifier DO-219(SMF) SL02 with a maximum average forward rectified current of 1.1A, a maximum peak voltage of 20V, and a maximum instantaneous forward voltage of V_FAnd 0.385V. Capacitors 332 and 334 may be 16V loose ECPU diaphragm stack capacitors having part numbers ECPU1C224MA5 and ECPU1C474MA5, with respective capacitors of 0.22 μ F and 0.47 μ F, and a capacitance tolerance of 20%. Resistor 336 may be a 100 Ω loose thick film chip resistor having part number ERJ3GEYJ101V, a nominal power of 0.125W at 70 ℃, and a resistance tolerance of ± 5%. Connecting additional resistor 336 may advantageously reduce the Q factor of the circuit in a manner known to those skilled in the art.

The RLC circuit 302 is adapted to the high-voltage coil type spark plug 316, such as the jeep type, which is a non-shielding structure. In other words, unlike the high coil spark plug shown in FIG. 1d, the high coil spark plug 316 does not have an igniter at its top. In contrast, the igniter (not shown) of the high-voltage coil type spark plug 316 is disposed externally, and the igniter shield does not attenuate the magnetic flux emitted from the iron core 318 of the high-voltage coil type spark plug 316. However, the absolute value of the magnetic flux is small and is not suitable for a capacitive sensor.

Fig.4a illustrates an inductive sensor 400 placed directly over a high-coil spark plug 410, as is currently used in a toyota engine. The RLC circuit (not shown) is connected in parallel to the lead-out wires (not shown) of the above-described inductive sensor. Unlike the unshielded configuration of the jeep high voltage coil spark plug shown in fig. 3, the toyota high voltage coil spark plug is shown in detail in fig. 1d and has an igniter including a shield 412 disposed on top of the high voltage coil spark plug. The shield 412 attenuates the magnetic flux emitted by the core 418 of the coil-on plug 410 described above. Due to the decay of the output flux, close contact between the inductor and the top of the high voltage coil spark plug is ensured and/or two or more sensors may be cascaded. The inductive sensor 400 may be disposed within a housing 422 that includes a biasing member 420, which may be, for example, a spring, to bias the inductive sensor 400 into intimate contact with the top surface of the coil-type spark plug 410. Also, a clip or an adhesive member may be used to improve the contact between the induction type sensor and the high-voltage coil type spark plug case.

Fig.4b illustrates one embodiment of the RLC circuit 302 of fig. 3 in more detail. Such a circuit comprising a high-voltage coil spark plug as described in fig. 1d and 4A is particularly suitable for use in a toyota vehicle.

In one example, switch 425 is a 3-bit miniature slide switch in the C & K switch product OS series (model number OS103011MS8OP1-SP 3T). Such a 3-bit switch is shown to have three positions a, b, c corresponding to the three pins of the RLC circuit. It is also good to use a digital switch having one or more on/off states. The leftmost pin c corresponds to Toyota high voltage coil spark plug structures 90919-. The middle pin b corresponds to Toyota high-voltage coil type spark plug structures 90919-. Finally, pin a on the right corresponds to Toyota high voltage coil spark plug configuration 90919-. It is to be understood that the above description is intended to be illustrative only and not exhaustive.

In such switchable configurations, the inductive sensor may be combined with a plurality of optional circuits, thereby allowing a technician to use a single sensor or sensing element in a wide range of home-use vehicles, such as Toyota vehicles, or in a variety of different engines, such as shielded or unshielded high-voltage coil spark plug configurations. Furthermore, multiple inductive sensors may be constructed using multiple circuits, allowing for broader use in a single package.

As shown, inductive sensor 310, which is element 430, is a 470 muH sensor. One suitable inductor is a 6000 series radial lead RF choke manufactured by J.W.Miller Magnetics of Gardenia, Canada, such as 6000-. Schottky diode 435 may be a standard semiconductor small surface mount Schottky rectifier DO-219(SMF) SL02 with a maximum forward rectified current of 1.1A, a maximum peak voltage of 20V, and a maximum instantaneous forward voltage of V_FAnd 0.385V.

Capacitors 445 and 455 may be 16V loose ECPU diaphragm stack capacitors having part numbers ECPU1C684MA5 and ECPU1C224MA5, with respective capacitors of 0.68 μ F and 0.22 μ F, and a capacitance tolerance of 20%. Capacitor 465 may be a 16V, loose ECHU (b) diaphragm stack capacitor having part number ECHU1C223JB5, a capacitance of 0..022 μ F, and a capacitance tolerance of ± 5%.

Resistor 440 may be 100 ΩA loose thick film chip resistor having a part number of ERJ3GEYJ101V, a rated power of 0.125W at 70 ℃ and a capacitance tolerance of + -5%. The resistors 450 and 460 may be a 150 Ω loose film resistor with part number ERJ3GEYJ151V, rated at 70 ℃ at 0.125W each, and a tolerance of ± 5% resistance. Cable 470 is a Snap-on Diagnostics^TMPigtail high voltage coil spark plug plate, part number 3683-01, has a built-in player connector. The output of the circuit may be provided to the input of the Vantage-KV module and any conventional motor analyzer or waveform display device, such as an oscilloscope, may be used when an appropriate parallel capacitor is included. The KV module input impedance is the bottom half of a 10,000: 1 capacitive divider, which behaves primarily as a capacitive impedance to the inductive sensor and current output.

Although the above circuits are described in terms of specific manufacturers and vehicle models, the actual circuits are more relevant to the type and geometry involved with the dedicated coils. The teachings herein are not limited to providing diagnostic test information only for a particular manufacturer and model or vehicle model, but rather useful for a high coil spark plug system for all engines or vehicles.

Specific embodiments are not limited to only the above-described circuits, but more broadly include any circuit capable of outputting the voltage generated by an inductive sensor (e.g., 310) by a technician or a processing device (e.g., a computer) in a manner suitable for identifying the ignition wire or spark wire end point, so as to allow determination of the combustion time by comparing or accumulating the time between the ignition wire and the spark wire end point. In various forms, the above-described embodiments may include circuits having "standard" components, wherein a single circuit is suitable for a large number (e.g., 100 or more) of different high-coil spark plugs. Such a single circuit may include, for example, an impedance alone or in combination with a potentiometer, to cover a desired single value or range of resistances to accommodate a large number of different high coil spark plug designs. Such circuitry also includes a variable inductor which may be, but is not limited to, a wire-cored or cup-cored inductor, and a single inductor may similarly have a number of different high-voltage coil-type spark plug forms. The circuit here may comprise a plurality of "semi-standard" circuits with appropriate selection means for convenience. Wherein a plurality of variable circuits are provided to cover all high coil spark plug designs. Alternatively, a suitable capacitor may be included.

In addition, the above-described circuitry is suitable for the typical coils and structures discussed above. If additional shielding is provided, or if other configurations of the high voltage coil spark plug described above are possible to further reduce the effective magnetic flux described above, additional circuit components, such as amplifiers or signal processors, may also be employed in the circuit according to the present invention.

An explanation of the operation of the above described inductive sensor and circuit shown in fig. 3 will be described with reference to fig. 5a-5 b. Fig.5a shows the voltage across the inductive sensor 310 measured using a bench test rig. The upper curve designated as channel 1 is the voltage output of the Tek (Tektronix) P60151000: 1HV probe. The probe is connected to the secondary coil of a high-voltage coil type spark plug. The voltages are displayed by a Tek TDS220 oscilloscope. As shown, channel 1 is scaled to 5.00 kV. The lower curve labeled channel 2 is the voltage measured by inductive sensor 310. Channel 2 is graduated at 1.00V. As shown at the bottom of fig.5a, each patch represents an increment of 25.0 μ s. Fig.5a shows an enlarged scale of negative peaks 505 and 515 representing equivalent ignition lines for flux and current. The first peak 505 occurs simultaneously with ignition and extinction of the primary region. The second peak 515 occurs approximately 20 microseconds later due to the time delay of the RLC circuit described above and is proportional to the ignition line voltage. Although the peak voltage is negative, this is arbitrary and the voltage may be set to a positive value, for example by an absolute value circuit known to those skilled in the art or the wires of the inductive sensor may simply be reversed connected.

Fig.5b shows the waveforms generated by the RLC circuit 302 on a different scale. Channel 1 is the actual ignition line voltage on the scale of 5.00 kV. Channel 2 is the ignition wire voltage measured using inductive sensor 310 on a 500mV scale. Each small block represents an increment of 500 μ s, as described below. This enlarged view shows the entire ignition line, the start 590 of the waveform and the spark line 595 and the end 596 of the burn period. In a manner well known to those skilled in the art, the above-described burn time shown in fig.5b can be extracted from a waveform observed from the known behavior of a high-coil spark plug system, as described in relation to fig.2a and 2 b. Approximately speaking, it will be apparent that the burn time may be determined by measuring the onset of oscillations or "ringing" that occur from the start of the ignition wire 590, at the beginning of a noticeable waveform on the viewing or printing device associated with the inductive sensor 310, to approximately one millisecond or more, at which point the voltage returns above the zero voltage line, indicating the disappearance of the spark between the electrodes.

Although the amplitude of the start waveform 590 is not linearly proportional to the actual voltage of the ignition line, it is proportional to the actual voltage of the ignition line in the range where many COP coils are applicable. The amplitude of waveform 590 increases when the actual firing voltage increases and decreases when the actual firing voltage decreases. However, in an inductive system, when the actual ignition voltage goes to zero, the amplitude of waveform 590 is not zero and the spark plug gap is small or nearly so, causing the ignition voltage to go to zero, wherein a short circuit or non-spark current is directed to ground through the internal resistance of the spark plug, maintaining the flux in the core as a result of the continued flow of current in the coil secondary winding. Thus, it is believed that ignition wire 590 provides both a measure of the ignition wire and an equivalent function.

FIGS. 6a-6b through 9a-9b show the results of the testing of the foregoing bench test setup, in which the actual voltage output of the Tek (Tektronix) P60151000: 1HV probe connected to the high-voltage coil spark plug and the voltage output of the inductive sensor 310 were measured and compared. The voltage output of the inductive sensor 310 is actually measured using two devices. The first device is a Snap-on tool voltage module hand-held tester, and the second device is an additional oscilloscope with higher bandwidth and precision than the hand-held tester. Fig. 6a, 7a, 8a, 9a show the ignition wire voltage in kilovolts as a function of the number of turns in the adjustable gap opening used for testing purposes so that the gap of the spark plug gap can be varied. Fig. 6b, 7b, 8b, 9b show the burn time in milliseconds as a function of the ignition wire voltage amplitude.

FIGS. 6a and 6b show the results of a Toyota high-coil spark plug, part No. 90080-. In fig. 6a, the ignition wire voltage measured by the Tek probe was 6.0, 7.0, 8.0, 12.0 and 15.0V for each gap turn (gaptum) of 1.0, 2.0, 3.0, 4.0 and 5.0, respectively. The corresponding values for the hand-held tester are 5.2, 5.6, 6.4, 8.0 and 11.7V. The corresponding values of the oscilloscope are 6.0, 7.0, 7.0, 9.0 and 13.0V. In fig. 6b, the number of turns per gap is 1.0, 2.0, 3.0, 4.0 and 5.0, and the burning time measured by the Tek probe is 1.7, 1.6, 1.4, 1.3 and 1.2 milliseconds for each of the previously described ignition wires (kV), respectively. The corresponding values for the hand-held tester are 2.0, 1.9, 1.7, 1.6 and 1.4 milliseconds. The corresponding values for the oscilloscope are 1.8, 1.6, 1.4, 1.3 and 1.2 milliseconds.

FIGS. 7a and 7b show the results of a Toyota high-voltage coil spark plug, part number 90919-. In fig. 7a, the ignition wire voltage measured by the Tek probe was 5.0, 6.0, 8.0, 11.0 and 14.0V for each gap turn of 1.0, 2.0, 3.0, 4.0 and 5.0, respectively. The corresponding values for the hand-held tester are 5.2, 5.2, 5.4, 8.2 and 13.9V. The corresponding values of the oscilloscope are 5.0, 6.0, 7.0, 8.0, and 12.0V. In fig. 7b, the number of turns per gap is 1.0, 2.0, 3.0, 4.0 and 5.0, and the burning time measured by the Tek probe is 1.9, 1.7, 1.7, 1.4 and 1.2 milliseconds for each of the previously described ignition wires (kV), respectively. The corresponding values for the hand-held tester are 2.1, 1.8, 1.8, 1.6 and 1.4 milliseconds. The corresponding values for the oscilloscope are 1.9, 1.7, 1.6, 1.5 and 1.3 milliseconds.

FIGS. 8a and 8b show the results of a Toyota high-coil spark plug, part number 90919-. In fig. 8a, the ignition wire voltage measured by the Tek probe was 5.0, 6.0, 8.0, 12.0 and 14.0V for each gap turn of 1.0, 2.0, 3.0, 4.0 and 5.0, respectively. The corresponding values for the hand-held tester are 4.4, 4.6, 5.6, 7.6 and 10.7V. The corresponding values of the oscilloscope are 5.0, 5.0, 6.0, 8.0, and 11.0V. In fig. 8b, the number of turns per gap is 1.0, 2.0, 3.0, 4.0 and 5.0, and the burning time measured by the Tek probe is 1.8, 1.5, 1.5, 1.3 and 1.2 milliseconds for each of the previously described ignition wires (kV), respectively. The corresponding values for the hand-held tester are 1.9, 1.8, 1.6, 1.5 and 1.3 milliseconds. The corresponding values for the oscilloscope are 1.7, 1.5, 1.6, 1.3 and 1.2 milliseconds.

FIGS. 9a and 9b show the results of a Toyota high-voltage coil spark plug, part number 90919-. In fig. 9a, the ignition wire voltage measured by the Tek probe was 5.0, 7.0, 8.5, 12.0 and 15.0V for each gap turn of 1.0, 2.0, 3.0, 4.0 and 5.0, respectively. The corresponding values for the hand-held tester are 4.4, 4.6, 5.6, 7.6 and 10.7V. The corresponding values of the oscilloscope are 5.0, 5.2, 7.0, 10.0 and 15.6V. In fig. 9b, the number of turns per gap is 1.0, 2.0, 3.0, 4.0 and 5.0, and the burning time measured by the Tek probe is 1.9, 1.8, 1.8, 1.4 and 1.3 milliseconds for each of the previously described ignition wires (kV), respectively. The corresponding values for the hand-held tester are 2.1, 2.0, 2.0, 1.6 and 1.4 milliseconds. The corresponding values for the oscilloscope are 1.9, 1.8, 1.7, 1.4 and 1.3 milliseconds.

FIGS. 10a and 10b show the results of a Toyota high-coil spark plug, part number 90919-. As shown in fig. 10a, the ignition wire voltage measured by the Tek probe was 5.0, 7.0, 8.0, 11.0 and 15.0V for each gap turn of 1.0, 2.0, 3.0, 4.0 and 5.0, respectively. The corresponding values for the hand-held tester are 5.2, 5.0, 4.8, 5.0 and 8.0V. The corresponding values of the oscilloscope are 6.0, 5.0, 5.0, 5.0 and 8.0V. In fig. 10b, the number of turns per gap is 1.0, 2.0, 3.0, 4.0 and 5.0, and the burning time measured by the Tek probe is 2.0, 1.8, 1.6, 1.5 and 1.4 milliseconds for each of the previously described ignition wires (kV), respectively. The corresponding values for the hand-held tester are 2.1, 1.8, 1.6, 1.5 and 1.3 milliseconds. The corresponding values for the oscilloscope are 2.0, 1.8, 1.6, 1.5 and 1.3 milliseconds. As is clear from fig. 10a and 10b, the above-mentioned burning time is acceptably detected and determined. The ignition wire is not precisely replicated. In this case a dual inductor arrangement, comprising two Miller 6000-471K inductors, is connected for boosting in a manner known to the person skilled in the art, so that the signal can be effectively doubled. A single 200 omega resistor is connected across the dual coil output to define the ringing period. But this value may also be varied to suit a particular COP characteristic. This configuration produces good results as shown in fig.11 a-11 h.

11a-11h show results for one aspect of a dual-induction sensor configuration. FIG.11a relates to 90919-. The rightmost three vertical bars are likewise similar showing the burn times measured by the hand-held device described above for the normal gap (1.25 milliseconds), the short circuit gap (2.2 milliseconds) and the near open circuit gap (1.0 milliseconds), respectively. In this particular arrangement, the 200 Ω parallel damping resistor is removed so that the voltage provided by the self-induced magnetic flux continues to exceed the threshold of the ignition wire, thereby ensuring a display on the display. As shown in fig.11a, there is significant consistency between the oscilloscope and the handheld device with respect to each of the normal gap (1, 4), the short circuit gap (2, 5) and the near open gap (3, 6).

FIGS. 11b-11h relate to 90919-. Similar to fig.11a, these figures show the correspondence between the oscilloscope displays obtained and the readings of the combustion times for each indicated COP and respectively for the normal gap (1, 4), the short circuit gap (2, 5) and the near open gap (3, 6). Fig.11b (90919-. Fig.11c (90919-.

Fig.12 a-12b illustrate the diagnostic efficacy of the detection of the above described embodiment of a dual inductor high voltage coil spark plug sensor (DLCOP). Fig.12a shows the relationship between the shorted spark plug versus the normal gap expressed in percentiles and the various coils assigned an arbitrary number and corresponding to the COP indicated by the last digit of the COP manufacturer's part number. Fig.12b shows the relationship between the open spark plug versus the normal gap expressed in percentiles and the various coils assigned an arbitrary number and corresponding to the COP indicated by the last digit of the COP manufacturer's part number. The "open-to-normal%" is determined based on the absolute value of the difference between the normal gap combustion time and the above-described open-spark combustion time of the spark plug divided by the normal gap combustion time and multiplied by 100. "short-to-normal%" is similar to the above calculation except that the spark plug open combustion time is replaced with the spark plug short combustion time. As described above, the higher the percentile, the easier it is for a user or a technician to identify the difference between a normally operating spark plug and a short-circuited spark plug (circuit). Coil #9(28138) corresponds to a Jeep COP (Clesiler P/N56028138). The remaining coils correspond to various Toyota COPs. From the above description, although the graphs shown in fig. 6a to 6b and fig.11a to 11h show a general relationship between the actual ignition voltage (Tek kV) and the sampled voltage of the induced magnetic flux, the above detection diagnosis value is not just to provide an accurate value of the ignition voltage since there is no accurate correspondence value between the actual ignition voltage (Tek kV) and the sampled voltage of the induced magnetic flux. For example, the diagnostic test values are inherent to the relative magnitude of the ignition wire voltage between each of the plurality of high-coil spark plugs to determine differences therebetween, or are inherent to time-based phenomena such as combustion time proportional to the actual ignition voltage. For example, if the technician places the inductive sampling circuit over a plurality of high-voltage coil-type spark plugs and the equivalent firing line voltage of all but one of the high-voltage coil-type spark plugs is 6kV, and the value of this one is 20kV, it is likely that 20kV indicates that a problem is occurring that needs further evaluation.

In accordance with the disclosure herein, the magnitude of the burn time may be extracted from the waveform measured using an inductive sampling technique, in a manner well known to those skilled in the art, based on observing the known behavior of the above-described high-coil spark plug system described with respect to fig.2a and 2 b.

Because the inventive inductive coupling sampling can measure the low coil area, the inductive coupling sampling (referred to as LCOP) of the ignition high voltage coil/coil-wound spark plug described herein according to the present invention can achieve an improvement in the capacitive coupling sampling (referred to as CCOP) of the ignition high voltage coil/coil-wound spark plug.

By comparison, the CCOP system produces a reasonably linear representation of the spark plug gap voltage in the voltage range of 0-50kV immediately before disconnection from (ignition line or power kV), while LCOP produces a non-linear relative representation in the voltage range of less than 10kV to greater than 30 kV. The above-described performance of CCOP and LCOP is essentially the same with respect to measurements during a spark plug gap fault (burn time, spark time). In determining the voltage during combustion (spark line, spark voltage kV, combustion voltage kV), the above-described CCOP system produces a reasonably linear representation, ranging from less than 1kV to more than 4kV, while LCOP also produces a reasonably linear relative representation over the same voltage range described above. For the detection of the above-mentioned problems, such as spark plug short circuit or winding, the standard voltage of the spark plug gap during a malfunction of CCOP is only 10V, and the burning time and the power source kV (voltage of ground resistance spark plug tip) are also low. The LCOP described above is also similar; but its supply kV may appear normal. Diagnostically, the spark line can also be used in the LCOP system, since it drops to 50% of normal. The LCOP and CCOP described above have equal capabilities with respect to the detection of an open circuit in the secondary coil or in the spark plug or problems with dwell time.

The embodiments described herein may include or may utilize a suitable voltage source, such as a battery, an alternator, etc., to provide a suitable voltage, such as about 12 volts, about 42 volts, etc.

The embodiments described herein may utilize any desired ignition system or engine. These systems or engines may include components that utilize organic or petrochemical fuels and their derivatives, which may be gasoline, natural gas, propane, etc., or combinations thereof. These systems or engines may be utilized or integrated into another system, such as an automobile, truck, boat or ship, electric bicycle, generator, airplane, and so forth.

Various aspects of the invention are described in this disclosure for the purpose of illustrating its versatility. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein. For example, a single high-coil spark plug may use multiple inductors. The sensing device may comprise a plurality of similar sensing devices or may comprise a combination of different sensing devices having different characteristics. The method of the present invention is also broadly related to the use of capacitive sensors, such as but not limited to those described in U.S. patent No. 6,396,277, published 5-28-2002, which is incorporated herein by reference, to determine burn time. Furthermore, while examples of the above-described apparatus and methods are discussed, the present invention is not limited to the examples provided herein, and other variations of the invention are defined by the appended claims.

Claims (23)

1. A coil-on plug testing apparatus for generating an output signal representative of an ignition signal, comprising:

an inductive sensor connectable to a high-tension coil spark plug device for sensing an electromagnetic flux generated by the high-tension coil spark plug device during an ignition event and generating and outputting a voltage in response to the sensed electromagnetic flux;

and a signal processing circuit electrically connected to the inductive sensor for generating an output signal in response to a change in voltage output by the inductive sensor in response to the detected electromagnetic flux.

2. The coil-on-coil spark plug testing apparatus of claim 1 wherein said inductive sensor includes at least one of an open core inductor and an air core inductor.

3. The coil-on-coil spark plug testing apparatus of claim 1 including a housing carrying at least one of a clamp and a magnetic element for attaching said inductive sensor to said coil-on-coil spark plug assembly.

4. The coil-on-plug testing apparatus as defined in claim 1 including a housing carrying a biasing member for connecting said inductive sensor to said coil-on-plug.

5. The coil-on-coil spark plug testing apparatus of claim 1 wherein said signal processing circuit includes an RC circuit connected in parallel with said inductive sensor.

6. The coil-on-coil spark plug testing device of claim 5 wherein said signal processing circuit includes a schottky diode connected in parallel with said inductive sensor.

7. The coil-on-coil spark plug testing apparatus of claim 5 wherein said signal processing circuit includes a variable resistor.

8. The coil-on-coil spark plug testing apparatus of claim 5 wherein said inductive sensor comprises a variable inductor.

9. The coil-on-coil spark plug testing apparatus of claim 6 wherein said inductive sensor comprises a variable sensor.

10. The coil-on-coil spark plug testing apparatus of claim 1 wherein said signal processing circuit includes a plurality of RC circuits having different combinations of resistance and capacitance, said plurality of RC circuits being connected in parallel with said inductive sensor by a switching element.

11. The coil-on-coil spark plug testing apparatus of claim 10 wherein said switching element is a multi-position switch.

12. The coil-on-coil spark plug testing apparatus of claim 10 wherein said switching element is a digital switch.

13. A method for determining a burn time for a coil-on plug ignition device, the steps comprising:

an induction type sensor is arranged close to a shell of the high-voltage coil type spark plug ignition device;

detecting, using the inductive sensor, an electromagnetic flux output by the high-coil spark plug ignition device during a period including at least one ignition phase; and are

The time of combustion is determined and,

wherein the step of determining the burn time includes identifying an equivalent ignition line and identifying the end points of the spark line, and determining the time between the ignition line and the end points of the spark line.

14. A method of determining a burn time for a high voltage coil plug ignition device as claimed in claim 13, further comprising adjusting the voltage in response to the detected electromagnetic flux.

15. The method of determining burn time for a high tension coil plug ignition device of claim 13 wherein said step of positioning includes removably attaching said inductive sensor to an exterior of a housing of said high tension coil plug ignition device.

16. The method of determining burn time for a high tension coil plug ignition device of claim 13 wherein said positioning step includes clamping at least one of an inductive sensor and an inductive sensor housing to a housing of said high tension coil plug ignition device.

17. The method of determining burn time for a high voltage coil plug ignition device of claim 13 wherein said positioning step includes clamping at least one of the inductive sensor and the inductive sensor housing to an engine compartment assembly.

18. A method of determining burn time for a high voltage coil plug ignition device, as claimed in claim 13, further comprising outputting said determined burn time to at least one of a display device, a printing device and an indicating device.

19. A method of determining burn time for a high-tension coil plug igniter of claim 13, further comprising the step of disposing a plurality of inductive sensors adjacent a corresponding plurality of high-tension coil plug igniter housings.

20. A method of detecting a problem associated with a high coil spark plug ignition device, comprising the steps of:

a) an inductive sensor is arranged adjacent to a shell of a first high-voltage coil type spark plug;

b) detecting, using the inductive sensor, an electromagnetic flux output by the high-coil spark plug ignition device during a period including at least one ignition phase;

c) identifying at least one of an ignition wire, a spark wire, and a burn time;

d) repeating steps a) -c) for a second high voltage coil spark plug; and are

e) At least one of the identified corresponding ignition wire, spark line and burn time for the first and second high voltage coil spark plugs is compared to determine a relative difference therebetween.

21. A method of detecting a problem associated with a high-coil spark plug ignition device as claimed in claim 20 wherein step e) includes comparing the identified burn times for the first and second high-coil spark plugs to determine the relative difference therebetween.

22. A method of detecting a problem associated with a high coil spark plug ignition device, comprising the steps of:

a) disposing a sensor adjacent a housing of a first high voltage coil spark plug;

b) detecting electromagnetic radiation emitted by the high-coil spark plug ignition device using the sensor during a period comprising at least one ignition phase;

c) identifying at least one of an ignition wire, a spark wire, and a burn time;

d) repeating steps a) -c) for a second high-voltage coil-type spark plug; and

e) at least one of the identified corresponding ignition wire, spark line and burn time for the first and second high voltage coil spark plugs is compared to determine a relative difference therebetween.

23. A method of detecting a problem associated with a high-coil spark plug ignition device as claimed in claim 22 wherein step e) includes comparing the identified burn times for the first and second high-coil spark plugs to determine the relative difference therebetween.