阅读说明：本技术 一种点火线圈输出能量评估方法及其测试系统 (Ignition coil output energy assessment method and test system thereof ) 是由 邓文谦 王玉军 李立伟 于 2021-01-20 设计创作，主要内容包括：本发明涉及发动机测试技术领域,具体地说是一种点火线圈输出能量评估方法及其测试系统,在发动机气缸内安装试验火花塞作为试验负载,启动发动机；当发动机水温稳定后,调整发动机,记录点火线圈的放电波形；计算发动机的真实点火能量需求值；试验负载为齐纳二极管,启动点火；调整点火线圈的充电时间,使输出能量与发动机的真实点火能量需求值相等,记录此时点火线圈放电电流波形,并获得放电电流峰值和放电时长。本发明同现有技术相比,基于当量空燃比均质燃烧发动机,进行实车真实点火能量的评估并通过负载切换,将测试得到的真实能量需求转换为齐纳二极管下相同能量输出下的放电电流峰值和放电时长,后续对点火线圈的优化设计奠定基础。(The invention relates to the technical field of engine test, in particular to an ignition coil output energy evaluation method and a test system thereof.A test spark plug is arranged in an engine cylinder to serve as a test load, and an engine is started; after the water temperature of the engine is stable, adjusting the engine and recording the discharge waveform of the ignition coil; calculating a true ignition energy demand value of the engine; the test load is a Zener diode, and ignition is started; and adjusting the charging time of the ignition coil to ensure that the output energy is equal to the real ignition energy required value of the engine, recording the discharge current waveform of the ignition coil at the moment, and obtaining the peak value and the discharge duration of the discharge current. Compared with the prior art, the method is based on the equivalent air-fuel ratio homogeneous combustion engine, the real ignition energy of the real vehicle is evaluated, the real energy requirement obtained through testing is converted into the discharge current peak value and the discharge duration under the condition of the same energy output under the Zener diode through load switching, and a foundation is laid for the subsequent optimization design of the ignition coil.)

1. An ignition coil output energy evaluation method is characterized in that: the method comprises the following steps: step 1, installing a test spark plug in a cylinder of an engine, switching a test load to the test spark plug, and starting the engine; step 2, after the water temperature of the engine is stable, adjusting the rotating speed of the engine to an initial rotating speed point, adjusting the load of the engine to full load, and recording the discharge waveform of the ignition coil within a period of time; step 3, the upper computer calculates to obtain a real ignition energy demand value E of the engine according to the discharge waveform of the ignition coil_demand(ii) a Step 4, switching the test load to a Zener diode, setting ignition frequency, and starting an ignition switch; step 5, adjusting the charging time of the ignition coil to ensure that the output energy E of the ignition coil under the load of the Zener diode is within the same charging time_zenerTrue ignition energy demand E with engine_demandRecording the discharge current waveform of the ignition coil at the moment, and obtaining a discharge current peak value I according to the discharge current waveform of the ignition coil_{sec_max}And discharge duration T_duration。

2. The ignition coil output energy evaluation method according to claim 1, wherein: the upper computer calculates to obtain a real ignition energy demand value E of the engine according to the discharge waveform_demandThe method comprises the following steps: step 3a, loading the discharge waveform data cluster of the ignition coil at different rotating speeds; step 3b, selecting a rotating speed, and extracting a discharge waveform data cluster at the rotating speed; step 3c, extracting the primary charging current waveform, the secondary discharging voltage waveform and the secondary discharging electricity under a single ignition cycle from the discharging waveform data cluster under the rotating speedFlow waveform, and counting the number of ignition cycles; step 3d, in the single ignition cycle process, based on the breakdown voltage of the mixed gas, identifying the charging stage of the ignition coil to the parasitic capacitor and the glow discharge stage of the ignition coil; step 3e, displaying the secondary discharge current value I according to the secondary discharge current waveform_secSecondary discharge voltage value U displayed with secondary discharge voltage waveform_secCalculating the secondary discharge power of different discharge stages, and integrating the secondary discharge power with time to obtain an output energy curve of the ignition coil, wherein the integral formula is(ii) a Step 3f, calculating the capacitor discharge energy after the mixed gas breakdown based on the ignition coil output energy curveAnd energy of glow discharge(ii) a Step 3g, repeating steps 3c to 3f, calculating the capacitor discharge energy E in each ignition cycle_breakContinuing to perform the step 3h until the calculation times are equal to the number of the ignition cycles; step 3h, discharging energy E to the capacitor in each ignition cycle_breakCarrying out the profile fitting of normal distribution to obtain a distribution value of 3 times of standard deviation as the ignition energy required value E under the rotating speed_{demand_rpm}(ii) a Step 3i, judging whether all the rotating speeds are traversed or not, if not, returning to the step 3b, and if so, continuing to perform the step 3 j; step 3j, ignition energy demand E at different rotational speeds_{demand_rpm}Taking the maximum value as the real ignition energy demand value E of the engine_demand。

3. The ignition coil output energy evaluation method according to claim 2, characterized in that: the discharge waveform data cluster of the ignition coil comprises a primary charge current discharge waveform cluster of the ignition coil, a secondary discharge current discharge waveform cluster of the ignition coil and a secondary discharge voltage discharge waveform cluster of the ignition coil.

4. A test system of an ignition coil output energy evaluation method according to claim 1, characterized in that: the device comprises an ECU engine control unit (1), an ignition coil (2), a current probe, a voltage probe (5), a high-speed data acquisition module (6), an upper computer (7) and a test load, wherein the ECU engine control unit (1) controls the ignition coil (2) to charge or discharge by driving an ignition module IGBT, the ECU engine control unit (1) sends load and rotating speed signals of an engine to the high-speed data acquisition module (6), a first current probe (3) records and monitors primary charging current waveforms of the ignition coil (2) at different engine rotating speeds on line, sends the collected primary charging current waveforms to the high-speed data acquisition module (6), a second current probe (4) records discharging current waveforms of the ignition coil (2) at different loads, sends the collected discharging current waveforms to the high-speed data acquisition module (6), and the voltage probe (5) records the voltage of a test spark plug (8) when mixed gas between two electrodes is punctured, the voltage signal is sent to the high-speed data acquisition module (6), the received signal is converted into digital quantity by the high-speed data acquisition module (6) and is transmitted to the upper computer (7), the upper computer (7) carries out parameter setting and control on the high-speed data acquisition module (6), switching control is carried out on test loads, the received data are stored, analyzed and calculated, and the test loads are switched in a test spark plug (8) and a Zener diode (9).

5. The system for testing the output energy of the ignition coil of claim 4, wherein: the load and rotating speed signal output end of an engine of the ECU engine control unit (1) is connected with a signal input end I of the high-speed data acquisition module (6), a driving signal end of the ECU engine control unit (1) is connected with a gate pole of an ignition module IGBT, an emitting pole of the ignition module IGBT is grounded, a collector electrode of the ignition module IGBT is connected with one end of a primary coil of an ignition coil (2), the other end of the primary coil of the ignition coil (2) is connected with a positive electrode of a storage battery, a measuring end of a current probe I (3) is arranged on a circuit between the ignition coil (2) and the positive electrode of the storage battery, a current waveform output end of the current probe I (3) is connected with a signal input end II of the high-speed data acquisition module (6), one end of a secondary coil of the ignition coil (2) is connected with a first end of a selector switch (10), a second end of the selector switch (10) is connected with one end, the third end of the selector switch (10) is connected with one end of the Zener diode (9), the test spark plug (8) and the other end of the Zener diode (9) are grounded, the measuring end of the voltage probe (5) is arranged on a circuit between the ignition coil (2) and the first end of the selector switch (10), the voltage signal output end of the voltage probe (5) is connected with the signal input end III of the high-speed data acquisition module (6), the other end of the secondary coil of the ignition coil (2) is grounded, the measuring end of the current probe II (4) is arranged on a circuit between the ignition coil (2) and the grounding end, the current waveform output end of the current probe II (4) is connected with the signal input end IV of the high-speed data acquisition module (6), and the data interaction end of the upper computer (7) is connected with the data interaction end of the high-speed data acquisition module (6).

6. The system for testing the output energy of the ignition coil of claim 4, wherein: the ignition coil (2) adopts a coil with the output energy of 80mJ-120mJ, and the size of the output energy is adjusted by adjusting the charging time.

7. The system for testing the output energy of the ignition coil of claim 4, wherein: the high-speed data acquisition module (6) is a data acquisition module at least provided with 5 independent channels, and the highest sampling frequency is at least 1 MHz.

8. The system for testing the output energy of the ignition coil of claim 4, wherein: and the current testing precision of the current probe II (4) is 1 mA.

9. The system for testing the output energy of the ignition coil of claim 4, wherein: the measuring range of the voltage probe (5) is 0-40KV, and the voltage testing precision is 0.1 KV.

10. The system for testing the output energy of the ignition coil of claim 4, wherein: the test spark plug (8) is an aged spark plug subjected to an engine durability test.

11. The system for testing the output energy of the ignition coil of claim 4, wherein: when the test load is switched to the Zener diode (9), the output voltage of the ignition coil (2) is clamped on the voltage stabilizing voltage, and the discharge current waveform of the ignition coil (2) is approximately linear and is attenuated to zero.

Technical Field

The invention relates to the technical field of engine testing, in particular to an ignition coil output energy evaluation method and a test system thereof.

Background

For the current mainstream engine technology, either a port injection PFI engine or an in-cylinder injection GDI engine, a homogeneous combustion mode with an equivalent air-fuel ratio of 1.0 is adopted.

The homogeneous combustion mode means that the mixture in the engine cylinder is uniformly mixed with 14.7kg of air and 1kg of oil gas before combustion. The combustion process of the homogeneous combustion mode is divided into two stages, wherein the first stage is a core expansion stage of laminar combustion, and the second stage is a turbulent combustion stage of rapid flame propagation.

The first combustion stage is the most critical stage in the whole combustion process, the combustion effect directly determines the combustion rate of the second stage, and finally influences whether the thermal efficiency of the engine meets the engineering development requirements or not. The first stage requires the energy provided by the ignition system, i.e., ignition energy, to initiate the chemical looping reaction of the combustible mixture, initiating combustion and forming a flame kernel that can expand stably to a volume large enough to initiate combustion in the second stage. Instability of the fire core or too slow an expansion rate can result in slow combustion in the second stage and even a misfire condition.

Because of the homogeneous combustion of the equivalent air-fuel ratio, the chemical energy of the mixture is stable, and the key factor causing the initial nucleation and its stable expansion is the ignition energy. How to convert the real ignition energy requirement of the stage into the development index of the output energy of the ignition coil is always a difficult problem which troubles the development of the ignition coil product. The output energy of the ignition coil is one of key technical indexes of the ignition coil, the size of the output energy directly determines the development cost of the ignition coil, if the output energy index of the ignition coil cannot be defined according to the real ignition energy of an engine, the output energy of the ignition coil is designed to be excessively redundant, and a series of problems that the reliability is reduced due to heat dissipation, the compact space cannot be arranged and the like are caused while the product cost is increased.

Therefore, it is very meaningful to obtain a real ignition coil output energy technical index from the ignition energy requirement of the engine and to reduce the cost of the ignition coil through lean design.

Currently, as disclosed in patent No. CN201210299081.0, the output energy of the ignition coil is still a blank to be evaluated in most of the methods for evaluating the output voltage of the ignition coil.

In order to solve the above problems, it is necessary to design an estimation method of ignition coil output energy based on the real ignition energy requirement of a stoichiometric homogeneous combustion engine and a test system thereof.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an estimation method and a test system for ignition coil output energy based on the real ignition energy requirement of a homogeneous combustion engine with equivalent air-fuel ratio.

In order to achieve the above object, the present invention provides an ignition coil output energy evaluation method, comprising the steps of: step 1, installing a test spark plug in a cylinder of an engine, switching a test load to the test spark plug, and starting the engine; step 2, after the water temperature of the engine is stable, adjusting the rotating speed of the engine to an initial rotating speed point, adjusting the load of the engine to full load, and recording the discharge waveform of the ignition coil within a period of time; step 3, the upper computer calculates to obtain a real ignition energy demand value E of the engine according to the discharge waveform of the ignition coil_demand(ii) a Step 4, switching the test load to a Zener diode, setting ignition frequency, and starting an ignition switch; step 5, adjusting the charging time of the ignition coil to ensure that the output energy E of the ignition coil under the load of the Zener diode is within the same charging time_zenerAnd an engineReal ignition energy demand value E_demandRecording the discharge current waveform of the ignition coil at the moment, and obtaining a discharge current peak value I according to the discharge current waveform of the ignition coil_{sec_max}And discharge duration T_duration。

Optionally, the upper computer calculates a real ignition energy demand value E of the engine according to the discharge waveform_demandThe method comprises the following steps: step 3a, loading the discharge waveform data cluster of the ignition coil at different rotating speeds; step 3b, selecting a rotating speed, and extracting a discharge waveform data cluster at the rotating speed; step 3c, extracting a primary charging current waveform, a secondary discharging voltage waveform and a secondary discharging current waveform under a single ignition cycle in the discharging waveform data cluster at the rotating speed, and counting the number of the ignition cycles; step 3d, in the single ignition cycle process, based on the breakdown voltage of the mixed gas, identifying the charging stage of the ignition coil to the parasitic capacitor and the glow discharge stage of the ignition coil; step 3e, displaying the secondary discharge current value I according to the secondary discharge current waveform_secSecondary discharge voltage value U displayed with secondary discharge voltage waveform_secCalculating the secondary discharge power of different discharge stages, and integrating the secondary discharge power with time to obtain an output energy curve of the ignition coil, wherein the integral formula is(ii) a Step 3f, calculating the capacitor discharge energy after the mixed gas breakdown based on the ignition coil output energy curveAnd energy of glow discharge(ii) a Step 3g, repeating steps 3c to 3f, calculating the capacitor discharge energy E in each ignition cycle_breakContinuing to perform the step 3h until the calculation times are equal to the number of the ignition cycles; step 3h, discharging energy E to the capacitor in each ignition cycle_breakCarrying out profile fitting of normal distribution to obtain the distribution value of 3 times standard deviation of the normal distribution at the rotating speedIgnition energy demand value E_{demand_rpm}(ii) a Step 3i, judging whether all the rotating speeds are traversed or not, if not, returning to the step 3b, and if so, continuing to perform the step 3 j; step 3j, ignition energy demand E at different rotational speeds_{demand_rpm}Taking the maximum value as the real ignition energy demand value E of the engine_demand。

Optionally, the discharge waveform data cluster of the ignition coil includes a primary charge current discharge waveform cluster of the ignition coil, a secondary discharge current discharge waveform cluster of the ignition coil, and a secondary discharge voltage discharge waveform cluster of the ignition coil.

The invention provides a test system of an ignition coil output energy evaluation method, which comprises an ECU engine control unit, an ignition coil, a current probe, a voltage probe, a high-speed data acquisition module, an upper computer and a test load, wherein the ECU engine control unit controls the ignition coil to charge or discharge by driving an ignition module IGBT, and sends load and rotating speed signals of an engine to the high-speed data acquisition module. And the first current probe records and monitors the primary charging current waveform of the ignition coil at different engine rotating speeds on line, and sends the acquired primary charging current waveform to the high-speed data acquisition module. And the current probe II records the discharge current waveform of the ignition coil under different loads and sends the collected discharge current waveform to the high-speed data acquisition module. And the voltage probe records the voltage when the mixed gas between the two electrodes of the test spark plug is broken down and sends a voltage signal to the high-speed data acquisition module. The high-speed data acquisition module converts the received signals from analog quantity to digital quantity and transmits the digital quantity to an upper computer. The upper computer sets and controls parameters of the high-speed data acquisition module, switches and controls test loads, and stores, analyzes and calculates received data. The test load was switched in the test spark plug and zener diode.

Optionally, the load and rotation speed signal output end of the engine of the ECU engine control unit is connected to the first signal input end of the high-speed data acquisition module, the driving signal end of the ECU engine control unit is connected to the gate of the ignition module IGBT, the emitter of the ignition module IGBT is grounded, the collector of the ignition module IGBT is connected to one end of the primary coil of the ignition coil, the other end of the primary coil of the ignition coil is connected to the positive electrode of the battery, the measuring end of the first current probe is disposed on the circuit between the ignition coil and the positive electrode of the battery, the current waveform output end of the first current probe is connected to the second signal input end of the high-speed data acquisition module, one end of the secondary coil of the ignition coil is connected to the first end of the selector switch, the second end of the selector switch is connected to one end of the test spark plug, the third end of the selector switch, The other end of the Zener diode is grounded, the measuring end of the voltage probe is arranged on a circuit between the ignition coil and the first end of the selection switch, the voltage signal output end of the voltage probe is connected with the signal input end III of the high-speed data acquisition module, the other end of the secondary coil of the ignition coil is grounded, the measuring end of the current probe II is arranged on a circuit between the ignition coil and the grounding end, the current waveform output end of the current probe II is connected with the signal input end IV of the high-speed data acquisition module, and the data interaction end of the upper computer is connected with the data interaction end of the high-speed data acquisition module.

Optionally, the ignition coil adopts a coil with output energy of 80mJ to 120mJ, and the size of the output energy is adjusted by adjusting the charging time.

Optionally, the high-speed data acquisition module is a data acquisition module with at least 5 independent channels, and the highest sampling frequency is at least 1 MHz.

Optionally, the current testing precision of the second current probe is 1 mA.

Optionally, the measuring range of the voltage probe is 0-40KV, and the voltage testing precision is 0.1 KV.

Optionally, the test spark plug is an aged spark plug subjected to an engine durability test.

Optionally, when the test load is switched to the zener diode, the output voltage of the ignition coil is clamped at the regulated voltage, and the discharge current waveform of the ignition coil is approximately linear and attenuates to zero.

Compared with the prior art, the invention designs the ignition coil output energy evaluation method and the test system thereof, and can be based on equivalent air-fuel ratioThe homogeneous combustion engine carries out real ignition energy evaluation of a real vehicle and converts the real energy requirement obtained by testing into a discharge current peak value I under the same energy output under the Zener diode through load switching_{sec_max}And discharge duration T_durationAnd a foundation is laid for the subsequent optimization design of the ignition coil.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

FIG. 2 is a data cluster of discharge waveforms for an ignition coil within 2s at a certain fixed speed under full load.

FIG. 3 is a schematic diagram of a single-ignition discharge waveform of the present invention.

FIG. 4 is a graph of the percentage of energy released by the ignition coil at various stages of discharge in accordance with the present invention.

FIG. 5 shows the capacitance discharge energy E obtained for a number of ignition cycles in accordance with the present invention_breakThe profile data and the positive-too profile were fitted to the graph.

FIG. 6 is a graph of the actual demand of the ignition coil as a function of engine speed according to the present invention.

FIG. 7 is a discharge waveform of an ignition coil of the present invention under Zener diode load.

Description of reference numerals: 1 is ECU engine control unit; 2 is an ignition coil; 3 is a current probe I; 4 is a current probe II; 5 is a voltage probe; 6 is a high-speed data acquisition module; 7 is an upper computer; 8 is a test spark plug; 9 is a Zener diode; and 10 is a selection switch.

Detailed Description

The invention will now be further described with reference to the accompanying drawings.

Referring to fig. 1, the invention provides a test system of an ignition coil output energy evaluation method, which comprises an ECU (electronic control Unit) 1, an ignition coil 2, a current probe, a voltage probe 5, a high-speed data acquisition module 6, an upper computer 7 and a test load. The load and rotating speed signal output end of an engine of an ECU engine control unit 1 is connected with a signal input end I of a high-speed data acquisition module 6, a driving signal end of the ECU engine control unit 1 is connected with a gate electrode of an ignition module IGBT, an emitting electrode of the ignition module IGBT is grounded, a collecting electrode of the ignition module IGBT is connected with one end of a primary coil of an ignition coil 2, the other end of the primary coil of the ignition coil 2 is connected with the anode of a storage battery, a measuring end of a current probe I3 is arranged on a circuit between the ignition coil 2 and the anode of the storage battery, a current waveform output end of the current probe I3 is connected with a signal input end II of the high-speed data acquisition module 6, one end of a secondary coil of the ignition coil 2 is connected with a first end of a selector switch 10, a second end of the selector switch 10 is connected with one end of a test spark plug 8, the other ends of the test spark plug 8 and the Zener diode 9 are grounded, the measuring end of the voltage probe 5 is arranged on a circuit between the ignition coil 2 and the first end of the selector switch 10, the voltage signal output end of the voltage probe 5 is connected with the signal input end III of the high-speed data acquisition module 6, the other end of the secondary coil of the ignition coil 2 is grounded, the measuring end of the current probe II 4 is arranged on a circuit between the ignition coil 2 and the grounding end, the current waveform output end of the current probe II 4 is connected with the signal input end IV of the high-speed data acquisition module 6, and the data interaction end of the upper computer 7 is connected with the data interaction end of the high-speed data acquisition module 6.

The ECU engine control unit 1 controls the ignition coil 2 to charge or discharge by driving the ignition module IGBT, and the ECU engine control unit 1 sends the load and the rotating speed signals of the engine to the high-speed data acquisition module 6.

The ignition coil 2 uses a coil with an output energy of 80mJ to 120mJ, preferably 110 mJ. The output energy is adjusted by adjusting the charging time. The purpose of an ignition coil with output energy redundancy is: the external characteristics of different engines, such as the working condition of a maximum load point, can be ensured to be reliably ignited, namely the output energy of the mixed gas can meet the ignition energy requirements of various homogeneous combustion engines.

The first current probe 3 records and monitors primary charging current waveforms of the ignition coil 2 at different engine rotating speeds on line, and the acquired primary charging current waveforms are sent to the high-speed data acquisition module 6, so that the situation that the charging current is overloaded to saturate a magnetic circuit is prevented, and the ignition coil 2 is damaged by overheating of the ignition module in the test process.

And the current probe II 4 records the discharge current waveform of the ignition coil 2 under different loads and sends the collected discharge current waveform to the high-speed data acquisition module 6. The current test precision of the current probe II 4 is 1 mA.

The voltage probe 5 records the voltage when the mixed gas between the two electrodes of the test spark plug 8 is broken down, and sends a voltage signal to the high-speed data acquisition module 6. The measuring range of the voltage probe 5 is 0-40KV, and the voltage testing precision is 0.1 KV. The high-speed data acquisition module 6 converts the received signals from analog quantity into digital quantity and transmits the digital quantity to the upper computer 7, the upper computer 7 sets and controls parameters of the high-speed data acquisition module 6, switches and controls test loads, and stores, analyzes and calculates the received data. The high-speed data acquisition module 6 is a data acquisition module with at least 5 independent channels, the sampling frequency can be adjusted, the highest sampling frequency is at least 1MHz, otherwise, the complete discharge waveform of the ignition coil cannot be recorded.

Switching of the test load between the test spark plug 8 and the zener diode 9 is achieved by switching the selector switch 10 between the second terminal and the third terminal.

The test spark plug 8 is an aged spark plug subjected to an engine durability test, and the electrode gap and the shape of the electrode of the aged spark plug can represent the aging level at the limit of the service life of the product.

The Zener diode 9 is a load for testing the output energy of the ignition coil, when the test load is switched to the Zener diode 9, the output voltage of the ignition coil 2 is clamped on the voltage stabilizing voltage, and the discharge current waveform of the ignition coil 2 is approximately linear and is attenuated to zero. Wherein, the regulated voltage is generally 1 KV. As shown in FIG. 7, under the Zener diode load, since the discharge voltage is a fixed value, the output energy determines the peak value I of the discharge current of the ignition coil_{sec_max}And discharge duration T_durationThese two criteria are typically input as the design of the ignition coil.

The invention relates to an ignition coil output energy evaluation method, which comprises the following steps:

step 1, selecting an engine to be tested and installing the engine on an engine pedestal, wherein the engine can reliably run on external characteristics, such as the output torque can reach the design target torque under the working condition of the maximum load point at each rotating speed. A test spark plug is installed in a cylinder of an engine, generally 1 cylinder is selected for installation, and the test load is switched to the test spark plug to start the engine.

And 2, after the water temperature of the engine is stable, adjusting the rotating speed of the engine to an initial rotating speed point, adjusting the load of the engine to full load, and recording the discharge waveform of the ignition coil within a period of time, wherein the discharge waveform data is shown in figure 2. In this example, the nominal engine water temperature is 90 degrees, the starting speed point is 1200rpm, and the period of time is 2 seconds.

And 3, calculating by the upper computer according to the discharge waveform of the ignition coil to obtain a real ignition energy required value Edemand of the engine, which is as follows:

and 3a, loading the discharge waveform data cluster of the ignition coil at different rotating speeds. The discharge waveform data cluster of the ignition coil comprises a primary charge current discharge waveform cluster of the ignition coil, a secondary discharge current discharge waveform cluster of the ignition coil and a secondary discharge voltage discharge waveform cluster of the ignition coil.

And 3b, selecting a rotating speed, and extracting the discharge waveform data cluster at the rotating speed as shown in figure 2.

And 3c, extracting a primary charging current waveform, a secondary discharging voltage waveform and a secondary discharging current waveform in a single ignition cycle from the discharging waveform data cluster at the rotating speed, and counting the number of the ignition cycles.

And 3d, identifying the charging stage of the ignition coil to the parasitic capacitor and the glow discharge stage of the ignition coil based on the breakdown voltage of the mixed gas in the single ignition cycle process. As shown in fig. 3, the minimum value of the secondary discharge voltage is the breakdown voltage of the mixture, and when the secondary voltage of the ignition coil reaches the maximum value, the voltage drops rapidly, which indicates that the mixture is broken down, the ignition coil finishes charging the secondary parasitic capacitor, and the capacitor starts to discharge rapidly. The charging stage of the ignition coil to the parasitic capacitance is carried out before the breakdown voltage of the mixed gas, and the glow discharge stage of the ignition coil is carried out after the breakdown voltage of the mixed gas.

Step 3e, displaying the secondary discharge current value I according to the secondary discharge current waveform_secAnd secondary dischargeSecondary discharge voltage value U displayed by voltage waveform_secCalculating the secondary discharge power of different discharge stages, and integrating the secondary discharge power with time to obtain an output energy curve of the ignition coil, wherein the integral formula is。

Step 3f, calculating the capacitor discharge energy after the mixed gas breakdown based on the ignition coil output energy curveAnd energy of glow discharge. The proportion of energy released in two stages under the waveform of the energy output by the ignition coil is shown in fig. 4

Step 3g, repeating the steps 3c to 3f, and calculating the capacitor discharge energy E after the mixed gas in each ignition cycle is broken down_breakAnd continuing to perform step 3h until the counting number is equal to the number of ignition cycles.

Step 3h, as shown in FIG. 5, discharge energy E to the capacitor in each ignition cycle_breakCarrying out the profile fitting of normal distribution to obtain a distribution value of 3 times of standard deviation as the ignition energy required value E under the rotating speed_{demand_rpm}. Since the system is suitable for ignition energy evaluation of homogeneous combustion engines, in which the capacitive discharge energy E_breakIs the only factor of successful ignition, and therefore the calculated capacitive discharge energy E_breakThat is, the required ignition energy E of the engine during this ignition process_demand。

And 3i, judging whether all the rotating speeds are traversed or not, if not, returning to the step 3b, and if so, continuing to perform the step 3 j.

Step 3j, shown in FIG. 6, ignition energy demand E at different rotational speeds_{demand_rpm}Taking the maximum value as the real ignition energy demand value E of the engine_demand. This value is used for the subsequent ignition coil external laboratory energy load: zener diode referenceThe value is obtained.

And 4, switching the test load to a Zener diode, setting ignition frequency and starting an ignition switch. In this example, the ignition frequency is 25 Hz.

Step 5, adjusting the charging time of the ignition coil to ensure that the output energy E of the ignition coil under the load of the Zener diode is within the same charging time_zenerTrue ignition energy demand E with engine_demandRecording the discharge current waveform of the ignition coil at the moment, and obtaining a discharge current peak value I according to the discharge current waveform of the ignition coil_{sec_max}And discharge duration T_duration. Output energy E of ignition coil under Zener diode load_zenerWill be greater than the true ignition energy demand E of the engine_demandBy reducing the charging time of the ignition coil, the two can be equalized.

Peak value of discharge current I_{sec_max}And discharge duration T_durationThe two indexes are usually used as key parameters for ignition coil performance design, and based on the two parameters, the two indexes can be used for the optimization design of internal parameters of the ignition coil, such as turn ratio and magnetic circuit structure, and the product optimization design is carried out on the premise of meeting the real energy requirement of an engine.

The invention designs an ignition coil output energy evaluation method and a test system thereof, which can evaluate real ignition energy of a real vehicle based on a homogeneous combustion engine with equivalent air-fuel ratio and convert the real energy requirement obtained by testing into a discharge current peak value I under the same energy output under a Zener diode through load switching_{sec_max}And discharge duration T_durationAnd a foundation is laid for the subsequent optimization design of the ignition coil.

The invention can help the user to evaluate the real ignition energy requirement of the research and development motivation, and help the user to select the product type and optimize the purchasing cost. Aiming at a small high-supercharging homogeneous combustion engine, the invention can guide the optimization design of the ignition coil, so that the lean design of the high-energy ignition coil becomes possible, and the competitiveness of the product in the market is obviously improved. According to the invention, through online monitoring of ignition discharge waveform data and a high-efficiency data analysis function, abnormal ignition phenomena such as ignition coil creepage, spark plug electrode flashover and the like can be effectively analyzed, a user is helped to search the cause of the abnormal ignition problem, and the processing cost of research and development and after-sale complaint events is reduced. The invention can not only detect the discharge waveform of the traditional ignition coil, but also is suitable for the detection and analysis of the discharge waveform of the ignition system of the advanced combustion engine.