A method of measuring ionic conductivity

 

The invention relates to the field of engine construction and can be used for diagnostics and control of internal combustion engines. The technical result consists in the possibility of applying for measuring ion conductivity of the gas medium between the electrodes of the spark plugs easy to implement the method, which has a high measurement accuracy and reduces the cost of implementing the measure. The method according to the invention is provided by measuring the time of flow of the discharge or charging current through periodically charging the capacitor, the plates of which are connected with the electrodes placed in the gas environment. 2 C.p. f-crystals, 6 ill.

The invention relates to engine and can be used for diagnostics and control of internal combustion engines (hereinafter referred to ice).

There is a method of measuring ion conductivity of the gas medium inside the combustion chamber of internal combustion engine [1], which serves a DC voltage to the electrodes of the spark plug placed in the combustion chamber of the internal combustion engine measured value flowing between the electrodes of the current, which is determined by the ionic conductivity casebotego process in the combustion chamber of the internal combustion engine, used for the diagnosis and management of ice.

The disadvantage of this method is the low value of the received signal of the ion current, its dependence on variations of the applied voltage and wide range of changes that requires the use of wide-band amplifiers with high gain and a multi-bit analog-to-digital converters (hereinafter ADC).

A prototype of the proposed method is taken way to measure the ionic conductivity of the gas environment within the combustion chamber of internal combustion engine [2], which periodically charge the capacitor, the plates of which are connected with placed in the gas environment of the combustion chamber electrodes, and determine the conductivity of the gas environment on the magnitude of the charge current of the capacitor. The shape of the curve ionic conductivity (ion current) is judged on the workflow settings in the cylinder, which are used for the diagnosis and management of ice.

The disadvantages of the prototype are insufficient measurement accuracy and the complexity of implementation of the method due to the following reasons.

The charge current of the capacitor depends on the variations of the voltage of the charge capacitor and varies within a very wide range.

To implement the method requires the use of a multi-bit ADC.

This problem is solved in the method of measuring the ionic conductivity of a gas medium by measuring the current flowing through the capacitor, the plates of which are connected with placed in the gas environment electrodes, including periodic charging of the capacitor.

The task is solved in that the magnitude of the ionic conductivity was measured as the time of current flow through a capacitor. This can measure the time of flow through the condenser discharge or charging current.

The invention is illustrated by the following drawings.

In Fig.1 shows a diagram of the ignition system of internal combustion engines, in which a possible implementation of the proposed method.

In Fig.2-6 shows the stresses at various points ignition system:

in Fig.2 shows the waveform of the voltage at the output 10 of the unit 1 control;

in Fig.3 shows the waveform of the output voltage of the secondary winding coil 5 ignition;

in Fig.4 shows the waveform of the voltage across the capacitor 8;

in Fig.5 shows the waveform of the voltage on the current-measuring resistor 9;

in Fig.6 shows the waveform of the voltage at the output of the threshold device 6.

The inventive method can be successfully R is placed in the combustion chamber of the internal combustion engine one of the electrodes which is connected with the mass of ice, and channel 3 plugs, consisting of a power switch 4, coil 5 ignition threshold device 6, a diode 7, a capacitor 8 and a current sensor, which can be used, for example, a Hall sensor or, as in this example implementation, the current-measuring resistor 9. Power to the ignition system is supplied from the source (Fig.1 not shown), a positive output which is conventionally shown in Fig.1 icon +12, and the negative output is connected to the mass of the internal combustion engine and is conventionally shown in Fig.1 icon mass.

In the General case, the ignition system may have many of the same ignition channel 3, is proportional to the number of cylinders of the engine.

The unit 1 control supplied with the output 10 control input 11 of the pulse duration measurement of the ion current. Key 4 is used for connecting the first output of the primary winding coil 5 ignition to the negative terminal of the power source, while the second terminal of the primary winding coil 5 ignition is connected to the positive output power supply +12, and the control input of the power key 4 is connected to the output 10 of block 1. The diode 7 is connected in series with the first high voltage output secondary winding coil 5 ignition, before the point p is AVOD secondary winding coil 5 ignition and the second output candles 2 plugs connected to the mass of ice. The second capacitor plate 8 is connected with the mass of ice directly in the case of use as a current sensor Hall sensor or through a current-measuring resistor 9, as in this example implementation. The connection point of the second capacitor plates 8 and the current-measuring resistor 9 is connected with the input of the threshold device 6, the output of which is connected to the input 11 of the pulse duration measurement unit 1 control.

The ignition system on the proposed method can be divided into two phases.

The first phase, the phase of forming the spark discharge, traditional and involves the accumulation of ignition energy, the breakdown of the spark gap of the spark on 2 plugs and maintaining a glow discharge.

The unit 1 control generates at its output 10 pulse duration T1 of the control key 4 (see Fig.2). Upon receipt of this pulse at the control input key last 4 switches the first output of the primary winding coil 5 ignition to ground. Through the primary winding coil 5 ignition begins to flow increasing from zero current, causing the appearance of the associated magnetic flux. In the magnetic field of the coil 5 ignition accumulate the energy necessary for the formation of a spark Paradise coil 5 ignition and, accordingly, the value stored in the magnetic field energy. When opening the primary circuit of the coil 5 ignition current generated by the current magnetic flux quickly decrease to zero, which causes self-induced EMF in the primary and secondary windings of the coil 5 ignition. The voltage EMF in the secondary winding coil 5 ignition increases until, until electrical breakdown of the spark gap of the spark plug 2 (see Fig.3). After the breakdown (Ua=7-15 kV) voltage on the electrodes of the spark plug 2 (see Fig.3) is reduced to the voltage sustaining glow discharge (Ub=500-700 B). The lifetime of the glow discharge is determined by the amount of stored energy, the magnitude of the discharge current and the combustion conditions, such as turbulence in the combustion chamber.

The first, traditional, phase of operation of the ignition system ends and begins the second phase - phase excitation and measurement of the ion current.

After completion of spark discharge unit 1 generates a series of control pulses with a repetition period T2 (see Fig.2). Primary and secondary winding coil 5 ignition form a system manitowaning oscillatory circuits, so that, acting on the oscillating circuit formed by the primary winding, causing the appearance of resonance oscillations in storires equal to the period of oscillations of the voltage of the secondary winding coil 5 ignition resulting in the secondary winding coil 5 ignition induced resonant oscillations of the voltage (see Fig.3), the positive half wave which passes through the diode 7, the charged capacitor 8 to the amplitude value Us (see Fig.4). Electrical breakdown of the spark gap spark 2 ignition when this does not occur, because the value of the Us (150-400) is much less than the breakdown voltage.

Being charged to a voltage Us, the capacitor 8 is discharged during the time TrasT2 - Tzur, where T2 is the pulse repetition period of the control, Tzur - time current flow of charge of the capacitor.

Consider two cases of discharge of the capacitor 8, depending on the conductivity value of the spark gap of the spark on 2 plugs.

The first case, when the period of time Tras there is a discharge of the capacitor 8 to zero, Tres<T2-Tzur.

In the first case, the discharge time of the capacitor 8 is entirely determined by the ionic conductivity of the spark gap of the spark plug and the charging time of the capacitor is constant and maximum for a given level of charge and is determined only by the parameters of the charging circuit, so at full charge it is advisable to measure the discharge time.

The second case, when going on what roudinesco gas medium between the electrodes 2 ignition (see Fig.4). Thus the discharge time of the capacitor is equal to the difference between Tras=(T2-Tzur), where Tzur is determined by the size of Ur.

In the second case, at a constant T2 (T2=const) the magnitude of the ionic conductivity can be determined by measuring the discharge time or the charging time of the capacitor 8.

As is known from electrical engineering, the integral of the charge current of the capacitor during the period T in steady state is equal to the integral of the discharge current over the same period.

Therefore, the slower will discharge the capacitor 8 in this period T2, the greater the magnitude of the residual voltage Ur (see Fig.4) and the smaller will be the magnitude and duration Tzur charging current of the capacitor 8 (see Fig.5).

Of electrical engineering is also known that the discharge time constant of the capacitor is equal to:

t=R·C,

where R (in our case) - the electrical resistance of the gas environment in the spark gap of the spark plug 2;

The capacitance value of the capacitor 8.

Thus, the time course of the discharge current of the capacitor 8 when other conditions are constant is determined by the electric resistance (or its inverse value of the conductivity) of the gas environment of the interelectrode gap candles 2 ignition.

The ionic conductivity of the spark gap spark 2 SAG is which, in turn, determined by the parameters of the workflow engine, such as the chemical composition of the fuel, temperature t and pressure P in the combustion chamber of the engine. Therefore, the magnitude of the ionic conductivity of the spark gap of the spark plug can be judged on parameters of the workflow engine.

In the process of charge/discharge of the capacitor 8 through the current-measuring resistor 9 current flows, causing the fall of the positive/negative voltage, which is applied to the input of the threshold device 6, which represents the voltage comparator. A threshold device 6 sets at its output the level of the log.1 at the lower input voltage below zero and the level of the log.0 when exceeding the input voltage is above zero (see Fig.6), and the duration of the pulse generated at the output of the threshold device 6, is equal to the discharge time of the capacitor 8. The voltage pulse from the output of the threshold device 6 (see Fig.6) is supplied to the input 11 of the unit 1 control, which produces a measurement of its length, for example, by means of a counter by counting pulses of a given frequency during the existence of the pulse voltage at the input 11 and memorizing pulse duration, uniquely determines the value of innoue end in the cylinder spark discharge capacitor, plates which are connected with placed in the gas environment electrodes of the spark plug, charge current pulses to a set of amplitude values.

- Measure the magnitude of ionic conductivity by measuring the current flowing through the capacitor. When this can perform the measurement of the charge and discharge current.

As is known from measurement technique, measurement of time at the moment is the most accurate and cheapest form of measurement. In addition, the proposed method does not have a pronounced dependence on the magnitude of the applied voltage (t=RC). So there is no need to precisely stabilize the charge voltage. Therefore, the application of the proposed method allows comparison with the known methods to improve the accuracy of measuring the ionic conductivity of the gas environment and reduce the cost of implementing the measure.

Sources of information

1. SAE paper No. 930461. Spark Plug Voltage Analysis for Monitoring Combustion in Internal Combustion Engine”. Yuichi Shimasaki, Masaki Kanehiro, Shigeki Baba, Shigery Maruyama and Takashi Hisaki. Honda R&D Co., Ltd. Shigery Miyata. NGK Spark Plug Co., Ltd.

2. RF patent №2109164. “Method of measurement of ionic current between the electrodes of the spark ignition internal combustion engines”, MPK F 02 P 17/00, publ. 20.04.1998,, bull. No. 11.

Formula sobrecargas capacitor, plates which are connected to electrodes placed in the environment, including periodic charging of the capacitor, characterized in that the measured time the current flowing through the condenser.

2. The method according to p. 1, characterized in that the measured time course of the discharge current.

3. The method according to p. 1, characterized in that the measured time course of the charging current.



 

Same patents:

The invention relates to electrical engineering, in particular to devices for measuring the parameters of the spark discharge in the spark plugs

Ice ignition device // 2367813

FIELD: engines and pumps.

SUBSTANCE: proposed invention relates to automotive ICE ignition devices. Proposed ignition device comprises ignition plug insulance recorders, anti-carbon devices, those to record the state of aforesaid anti-carbon devices and those to reveal conduction carbon deposits on ignition plug. With insulance falling below preset magnitude, engine is switched over to conditions allowing increasing ignition plug temperature. At aforesaid temperature, plug insulator cleaning of carbon deposit is intensified, the intensification process being recorded. With anti-carbonisation process readings exceeding preset ones and insulance below designed magnitude, increased carbon deposition is revealed and decided upon. In aforesaid case, light alarm signal on necessity of servicing ignition plug is issued.

EFFECT: intensification of carbon deposit removal from ignition plug.

10 cl, 8 dwg

FIELD: physics.

SUBSTANCE: method of determining test discharge parametres of capacitive ignition systems which consist of an ignition assembly, ignition cable and a spark plug, involves picking up a discharge current and voltage signal and determination of values of discharge parametres. The discharge current and voltage signal is picked up using analogue sensors. The current and voltage signals are picked up in auxiliary "short circuit" and "test load" modes, as well as in the main operation mode of the ignition system. Measurements are taken in digital form with given sampling frequency. Values of characteristic primary parametres are distinguished from measurement results. Values of intermediate parametres are determined for each assigned measurement mode using the obtained values of characteristic primary parametres. Values of test discharge parametres are determined using the obtained values of intermediate parametres.

EFFECT: possibility of measuring primary discharge parametres in digital form, picked up by analogue current and voltage sensors, more accurate measurement, obtaining information on efficiency of the spark plug and ignition system, discharge mode and energy factors and their change during operation or during an experiment.

3 dwg

FIELD: electricity.

SUBSTANCE: ignition plug (BR) is connected to generator (GEN) containing variable capacitor. The above generator includes also polarisation tools (MPOL) with option of ignition plug (BR) polarisation, which are connected between generator (GEN) and ignition plug (BR), and measurement instruments (MMES) for measurement of ion current at ignition plug (BR), which are connected between variable capacitor (Cb) and chassis ground.

EFFECT: improvement of measurement accuracy.

8 cl, 6 dwg

FIELD: electricity.

SUBSTANCE: device for radio frequency ignition includes control aids (5) designed with possibility of ignition control signal (VI) generation, power circuit (2) controlled by ignition control signal (VI) for power voltage supply to output interface (OUT) of power circuit at frequency determined by control signal, at least one resonator (1) of plasma generation connected to output interface of power circuit and designed with possibility of spark generation between two electrodes (10, 12) of ignition of the resonator during ignition command. This device includes means (6) for measuring of electrical parameter characterising change of resonator power voltage, module (7) for determination of state of electrodes contamination depending on measured electrical parameter and predetermined control value.

EFFECT: enhancing diagnostics of contamination state of radio-frequency coil-plug electrodes.

11 cl, 4 dwg

FIELD: engines and pumps.

SUBSTANCE: proposed device comprises voltage generator 5 and ignition unit 9 including ignition plug 4 and switch 7 arranged between plug feed terminal and generator output. Switch 7 allows connecting voltage generator output with said ignition plug 4 in response to command signal VI. Device comprises electronic control unit UC to generate said command signal VI. Said electronic control unit UC comprises means M to measure magnitudes characterising generator output voltage variations in time and device A to vary current voltage and/or frequency depending upon magnitudes set by said measuring means. Generator output voltage variation describes health of ignition plug (new or worn-out).

EFFECT: control over quality of plug spark.

9 cl, 2 dwg

FIELD: electrical engineering.

SUBSTANCE: invention relates to a measurement device, comprising the following components: radio frequency ignition power supply circuit (2) containing a transformer (T) the secondary winding whereof (LN) is connected to at least of resonator (1) having resonance frequency in excess of 1 MHz and containing two electrodes (11, 12) designed so that to enable spark generation when an ignition command is given; measuring capacitor (Cmesure) placed in series between the secondary winding and the resonator; circuit (DIFF) for measurement of current (Iion) of gases ionisation during burning inside a cylinder of the internal-combustion engine linked to the resonator. The said measurement circuit is connected to the measuring capacitor contacts and/or - circuit (RED) for measurement of voltage (Vout) on the resonator electrodes contacts when an ignition command is given. The circuit is connected to the measuring capacitor contacts.

EFFECT: possibility of simultaneous measurement of ionisation current and voltage.

8 cl, 4 dwg

FIELD: aircraft engineering.

SUBSTANCE: proposed method comprises measurement of time interval between sequential reservoir capacitor discharge current pulses running to spark plug and caused solely by switching of power stored at said capacitor and exceeding the preset check magnitude. Measured time interval is compared with preset time interval which describes the minimum repetition rate of spark discharge in the plug spark gap. Simultaneously, absence of the plug coaxial shielding ceramic insulator outer surface glow through slot is controlled, slot being made in plug body parallel with its axis. In operation of ignition system its serviceability is continuously defined. This is performed by the absence of the plug coaxial shielding ceramic insulator outer surface glow and difference between measured time interval and preset time interval which describes the minimum repetition rate of spark discharge in the plug spark gap.

EFFECT: higher validity of control.

3 dwg

FIELD: engines and pumps.

SUBSTANCE: control over engine cylinder including the ignition plug consists in decreasing of the cylinder load in response to advance ignition caused by deterioration in ignition plug parameters. Fuel-air mix is enriched in the cylinder in response to advance ignition caused by deterioration in ignition plug parameters.

EFFECT: higher accuracy of determination of deterioration in ignition plug parameters.

6 cl, 3 dwg

FIELD: transport.

SUBSTANCE: invention relates to field of transport and can be used for combustible mixtures ignition by means of electric spark, in particular in capacitive ignition systems for ignition system control, installed on aircraft engine, for ignition system technical condition evaluation in intervals between aircraft engines start-ups. Aircraft engines capacitive ignition system control device includes discharge current sensor, comparator, discharge current amplitude voltage check value setting device, time interval meter, actuator. Discharge current sensor output is connected to comparator first input, discharge current amplitude voltage check value setting device output is connected to comparator second input. Time interval meter output is connected to actuator. Control device additionally includes ambient environment pressure measuring transducer, containing serially connected ambient environment pressure sensor, amplifier, ambient environment pressure control voltage setting device, second comparator, univibrator, logical device "AND". Ambient environment pressure measuring transducer output is connected to second comparator first input. Ambient environment pressure control voltage setting device output is connected to second comparator second input, comparator output is connected to univibrator input, which output and second comparator output is connected to logical device "AND", by output connected to time interval meter input.

EFFECT: technical result is increasing of aircraft engines capacitive ignition system serviceability control reliability.

1 cl, 1 dwg

FIELD: electricity.

SUBSTANCE: processing unit for application in process control system includes output electrical diagram for connection of process control circuit with current control circuit going through it to transfer process-related information. Method of processing consists in that failure status is defined in processing unit connected to process control circuit. Output electrical diagram is disconnected as a response to the detected failure status. Output diagram is designed to control current in process control circuit. Circuit current is controlled until the required level is achieved at the stage of output electrical diagram disconnection.

EFFECT: output electrical diagram disconnection and setting of electrical current at the required level.

49 cl, 8 dwg

Up!