SPARK PLUG HEAT RATING MEASUREMENT METHOD AND SYSTEM BASED ON SPARK DISCHARGE CURRENT ACTIVE HEATING

Abstract

In the spark plug heat rating measurement method and system based on spark discharge current active heating, the spark plug is installed in a constant-temperature water jacket cooling chamber with a specific torque. A constant spark discharge current control module is connected to the high-voltage terminal of the spark plug, to provide real-time controlled discharge current to heat up the high-voltage central electrode of the spark plug. During the spark discharge process, the temperature change of the high-voltage central electrode and the surrounding ceramic insulator are measured by a temperature detection module and used to determine the heat rating of the spark plug. By real time adjusting the discharge current level of the spark plug, or providing a same amount of spark energy to the spark gap, the heat ratings of spark plugs with different ceramic insulation structures can be evaluated through the temperature changes during discharge or after discharge.

Claims

1. A spark plug heat rating measurement method based on spark discharge current active heating, wherein: during a spark discharge process, a spark discharge current is precisely adjusted to control the temperature of a spark plasma channel for heating up a high-voltage central electrode of the spark plug (5), and the temperature changes of the high-voltage central electrode and a surrounding ceramic insulator of the spark plug (5) are measured to evaluate a heat rating of the spark plug (5).

2. The spark plug heat rating measurement method of claim 1, wherein: the spark plug (5) is installed in a constant-temperature water jacket cooling chamber (50), and a constant spark discharge current control module (2) is connected to a high-voltage terminal of the spark plug (5); the constant spark discharge current control module (2) provides the constant controllable spark discharge current to the spark plug (5) to heat up the high-voltage central electrode through the high temperature of the spark plasma channel; during the discharge process, a real-time controller (1) dynamically adjusts the spark discharge current of the constant spark discharge current control module (2), based on a discharge current amplitude provided by a DC sensor (30), and the temperatures of the high-voltage central electrode and the surrounding ceramic insulator measured by a temperature measurement module (40), to control the temperature of the spark plasma channel and provide a required spark energy to heat up the central electrode of the spark plug (5).

3. The spark plug heat rating measurement method of claim 1, wherein: the temperature changes of high-voltage central electrodes and surrounding ceramic insulators of different spark plugs with different heat ratings are measured by placing the spark plugs in a temperature detection module (4) which includes the temperature measurement module (40); with a same amount of spark gap energy supplied to the spark plugs, the temperature changes of the ceramic insulators are measured to evaluate the heat ratings of the spark plugs and the heat dissipation characteristics of the ceramic insulators.

4. The spark plug heat rating measurement method of claim 3, wherein: the same amount of spark gap energy is supplied to the spark plugs with different heat ratings through a real time control of the spark discharge current, to heat up the high-voltage central electrodes and the ceramic insulators of the spark plugs; in order to precisely control the spark gap energy, a discharge duration is controlled between 10 s and 20 s, and a discharge current amplitude is controlled between 40 mA and 200 mA; by doing this, the temperature profiles of the high-voltage central electrodes and the surrounding ceramic insulators of the spark plugs are measured to compare the heat ratings of spark plugs with the different ceramic insulators.

5. The spark plug heat rating measurement method of claim 3, wherein: the spark discharge current is dynamically adjusted to control the temperatures of spark plasma channels of the spark plugs; the spark plasma channels are used to heat up the high-voltage electrodes of the spark plugs with different heat ratings; in the meantime, the discharge voltages at the spark plug terminals of the spark plugs and the spark discharge current are measured to calculate the heating powers of the spark plugs; with the constant spark discharge current control module (2), spark discharge current levels is adjusted in real time to ensure the instantaneous heating powers of the different spark plugs are the same during the heating process; with different heating durations, the high voltage electrodes and the surrounding ceramic insulators of the different spark plugs can be heated to the same temperature; the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators during the heating process are measured to evaluate the heat ratings of the spark plugs.

6. The spark plug heat rating measurement method of claim 3, wherein: with dynamically controlled the spark discharge current, using different heating powers or heating durations, spark plasma channels with different temperatures are generated to heat up the high-voltage central electrodes and the surrounding ceramic insulators of the spark plugs with different heat ratings to the same temperature; once the temperatures of the high-voltage central electrodes and the surrounding ceramic insulators of the different spark plugs reach the same temperature, the heating process is cut off, letting the spark plugs be cooled down naturally; during the spark plug cooling processes of the spark plugs, the temperature profiles of the high-voltage central electrodes and the surrounding ceramic insulators are recorded; since the heat rating of the spark plug reflects a heat dissipation capability of the high-voltage central electrode and the surrounding ceramic insulator, the spark plugs with different heat ratings will have different temperature profiles during the cooling process; the temperature profiles of the cooling process can be used to evaluate the heat ratings of the spark plug.

7. A spark plug heat rating measurement system based on discharge current active heating, wherein: the system comprises a constant spark discharge current control module (2), a real-time module (1), a spark discharge current measurement module (3), a temperature detection module (4), and the tested spark plug (5); the constant spark discharge current control module (2) is connected to a high-voltage terminal of the tested spark plug; the constant spark discharge current control module (2) provides a real time-controlled spark discharge current to heat up a high-voltage central electrode of the tested spark plug (5); the spark discharge current measurement module (3) is connected to both the tested spark plug (5) and the real-time module (1); the spark discharge current measurement module (3) is used to real time measure a spark discharge current amplitude and provides measurement results to the real-time controller (1); the temperature detection module (4) is connected to both the tested spark plug (5) and the real-time module (1); the temperature detection module (4) is used to monitor the temperatures of the high-voltage central electrode and the surrounding ceramic insulator of the tested spark plug (5), and feedback temperature signals to the real-time module (1); the real-time module (1) dynamically monitors and controls the output discharge current level of the constant spark discharge current control module (2).

8. The spark plug heat rating measurement system of claim 7, wherein: the temperature measurement module (4) includes the temperature measurement module (40), and a thermocouple temperature measurement system (70); the temperature measurement module (40) is mainly used to measure the temperature changes of the high-voltage central electrode and the surrounding ceramic insulator of the tested spark plug (5) during a discharge process, and provides a temperature information to a real-time controller (20) consisted of the real-time module (1); the temperature profiles of the high-voltage central electrode and the surrounding ceramic insulator measured during the discharge process are used as parameters to evaluate the heat rating of the tested spark plug (5); the tested spark plug (5) is installed in a constant-temperature water jacket cooling chamber (50); the thermocouple temperature measurement system (70) is used to measure the temperature of the constant-temperature water jacket chamber (50), and feedback to the real-time controller (20); the real-time controller controls a cooler (60), to ensure the temperature of the constant-temperature water jacket cooling chamber (50) is within 0-80° C.

9. The spark plug heat rating measurement system of claim 8, wherein: the spark discharge current measurement module (3) is a DC sensor (30), to real time measure the spark discharge current amplitude; the temperature measurement module (40) includes an infrared temperature measurement system, a thermocouple measurement system, and a laser-induced fluorescence detection system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 illustrates the control circuit of the measurement system in accordance with the present invention;

[0026] FIG. 2 is the heat dissipation paths of a spark plug during the heating process;

[0027] FIG. 3 is the assembly diagram of the spark plug in the constant-temperature water jacket cooling chamber.

[0028] FIG. 4 illustrates the comparison of the ceramic insulator temperature curves for spark plugs with two heat ratings in embodiment 1.

[0029] FIG. 5 illustrates the comparison of the ceramic insulator temperature curves for spark plugs with two heat ratings in embodiment 2.

[0030] FIG. 6 illustrates the comparison of the ceramic insulator temperature curves for spark plugs with two heat ratings during the cooling process in embodiment 3.

DESCRIPTION OF THE EMBODIMENTS

[0031] The present invention will now be described by embodiments, with reference to the attached drawings FIGS. 1 to 6. The embodiment 1 is the best application of the present invention.

Embodiment 1

[0032] Referring now to FIGS. 1 to 3, the present invention relates to a spark plug heat rating measurement system based on spark discharge current active heating, which includes the constant spark discharge current control module 2, the real-time control module 1, the spark discharge current measurement module 3, the temperature detection module 4, and the tested spark plug 5. The constant spark discharge current control module 2 is connected to the high-voltage terminal 8 of the tested spark plug 5. The constant spark discharge current control module 2 provides controllable spark discharge current to heat up the high-voltage central electrode 6 of the tested spark plug 5; the spark discharge current measurement module 3 is connected to both the tested spark plug 5 and the real-time control module 1, thereby to instantaneously measure the spark discharge current amplitude and feedback the measurement results to the real-time control module 1; the temperature detection module 4 is also connected to both the tested spark plug 5 and the real-time control module 1. The temperature detection module 4 is used to real time monitor the temperatures of the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5, and feedback the temperature signals to the real-time control module 1. The real-time control module 1 is used to dynamically monitor and control the output discharge current level of the constant spark discharge current control module 2. The tested spark plug 5 is installed in the constant-temperature water jacket cooling chamber 50 through a torque of 30 Nm. The constant-temperature water jacket cooling chamber 50 is cooled by the cooler 60. The temperature of the chamber body of the constant-temperature water jacket cooling chamber 50 is controlled within 0° C. −80° C. by the real-time control module 1. The real-time control module 1 consists of the real-time controller 20 and its control circuit. The real-time control module 1 is used to monitor the spark discharge current level and dynamically control the output discharge current level of the constant spark discharge current control module 2.

[0033] The temperature detection module 4 includes a temperature measurement module 40 for the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5, and a thermocouple temperature measurement system 70 for the constant-temperature water jacket cooling chamber 50; the temperature measurement module 40 is mainly used to measure the temperature changes of the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5 during the discharge process, and provide the measurement results to the real-time controller 20. The temperature curves of the high-voltage central electrode 6 and the surrounding ceramic insulator 80 measured during the discharge process are used as the parameters to evaluate the heat rating of the tested spark plug 5. The tested spark plug 5 is installed in the constant-temperature water jacket cooling chamber 50 through a torque of 30 Nm. The thermocouple temperature measurement system 70 is used to measure the temperature of the constant-temperature water jacket cooling chamber 50, and feedback the temperature to the real-time controller 20. The real-time controller 20 controls the cooler 60, to ensure the temperature of the constant-temperature water jacket cooling chamber 50 is within 0-80° C.

[0034] The spark discharge current measurement module 3 is a DC sensor 30. The DC sensor 30 is used to measure the spark discharge current amplitude. The temperature measurement module 40 for the high-voltage central electrode 6 and the surrounding ceramic insulator 80 includes an infrared temperature measurement system, a thermocouple measurement system, and a laser-induced fluorescence detection system.

[0035] The constant spark discharge current control module 2 consists of a constant spark discharge current control system 10 and its control circuit. The constant spark discharge current control system 10 is connected to the high-voltage terminal 8 of the tested spark plug 5 and the real-time controller 20 respectively. The constant spark discharge current control module 2 provides real-time controlled spark discharge current to the tested spark plug 5 to heat up the high-voltage central electrode 6.

[0036] The spark discharge current measurement module 3 consists of a DC sensor 30 and its control circuit. The DC sensor 30 is connected to the real-time controller 20 and placed beside the tested spark plug 5. The DC sensor 30 is used to measure the spark discharge current amplitude and feedback the measurement results to the real-time controller 20.

[0037] The temperature detection module 4 includes the temperature measurement module 40 for the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5, and the thermocouple temperature measurement system 70 for the constant-temperature water jacket cooling chamber 50. The temperature measurement module 40 is placed beside the tested spark plug 5, and also connected to the real-time controller 20. The temperature measurement module 40 is used to real time measure the temperatures of the high-voltage central electrode 6 and the surrounding ceramic insulator 80, and feedback the temperature to the real-time controller 20. The thermocouple temperature measurement system 70 is placed inside the constant-temperature water jacket cooling chamber 50, to real time measure the temperature of the chamber body of the constant-temperature water jacket cooling chamber 50 and feedback the chamber body temperature to the real-time controller 20.

[0038] FIG. 2 is the heat dissipation path of a spark plug when the high-voltage central electrode 6 is heated during the spark plug heat rating measurement process. The heat ratings of spark plugs with different ceramic insulator structures are determined by the temperature profiles of the high-voltage central electrodes and the surrounding ceramic insulators of the spark plugs. The spark plugs with different heat ratings are installed in the spark plug heat rating measurement system 9 through a torque of 30 Nm. FIG. 3 is the installation diagram of a spark plug in the constant-temperature water jacket chamber. In the instant embodiment 1, the temperature profiles of the high-voltage central electrodes and the surrounding ceramic insulators of spark plugs with different ceramic insulator structures are measured under the same spark gap energy conditions, with real time controlling of the spark discharge current amplitude. The temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators of the spark plugs are used to determine the heat ratings of the spark plugs.

[0039] The claimed precise control of the spark discharge current in the instant embodiment 1 is to install the tested spark plug 5 in the constant-temperature water jacket cooling chamber 50 with a torque of 30 Nm, and connect the high-voltage terminal 8 of the tested spark plug 5 to the constant spark discharge current control module 2. The constant spark discharge current control module 2 provides real-time controlled discharge current to the tested spark plug 5 to heat the high-voltage central electrode 6. During the discharge process, the discharge current amplitude of the constant spark discharge current control module 2 is adjusted by the real-time control module 1, based on both the spark discharge current amplitude measured by the DC sensor 30, and the temperatures of the high-voltage central electrode 6 and the surrounding ceramic insulator 80 in the vicinity of the spark plasma channel 7 provided by the temperature measurement module 40. By doing this, the constant spark discharge current control module 2 provides the needed spark gap energy to heat the high-voltage central electrode 6 of the tested spark plug 5.

[0040] The claimed method of measuring the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators of spark plugs with different ceramic insulator structures in the instant embodiment 1 is to install different spark plugs in the temperature detection module 4 with a torque of 30 Nm. The heat ratings of the spark plugs are evaluated by the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators measured under the same spark gap energy condition, thereby to indicate the heat dissipation characteristics of the ceramic insulators of the spark plugs. The claimed method of using the temperature changes of different spark plugs under the same spark gap energy condition to evaluate the heat ratings of spark plugs in the instant embodiment 1 is to supply the same amount of spark gap energy to the spark plugs, thereby to heat up the high-voltage central electrodes and the surrounding ceramic insulators (as shown in FIG. 1) by actively controlling the spark discharge current amplitude. By precisely controlling the discharge duration from 10 s to 120 s and the discharge current amplitude from 40 mA to 200 mA, the supplied spark gap energy of different spark plugs can be controlled to the same level. With the same spark gap energy, the temperature profiles of the high-voltage central electrodes and the surrounding ceramic insulators are measured by the temperature measurement module 40 to evaluate the heat ratings of different spark plugs.

EMBODIMENTS OF THE INVENTION

[0041] Apart from embodiment 1, the present invention can be applied in other embodiments.

Embodiment 2

[0042] The instant embodiment 2 has the same measurement principle as the embodiment 1, but uses different measurement methods. In the instant embodiment 2, the spark plug heat rating measurement system based on spark discharge current active heating includes the constant spark discharge current control module 2, the real-time control module 1, the spark discharge current measurement module 3, the temperature detection module 4, and the tested spark plug 5. The tested spark plug 5 is installed in the constant-temperature water jacket cooling chamber 50. The constant-temperature water jacket cooling chamber 50 is cooled by the cooler 60, and the temperature of the constant-temperature water jacket cooling chamber 50 is controlled by the real-time control module 1 to be constant at 0° C. or 80° C., wherein the real-time control module 1 consists of the real-time controller 20 and its control circuit. The real-time control module 1 is used to monitor the spark discharge current level and real time control the output current from the constant spark discharge current control module 2.

[0043] In the instant embodiment 2, the constant spark discharge current control module 2 consists of the constant spark discharge current control system 10 and its control circuit. The constant spark discharge current control system 10 is connected to the high-voltage terminal 8 of the tested spark plug 5 and the real-time controller 20 respectively. The constant spark discharge current control module 2 provides dynamically controlled spark discharge current to the tested spark plug 5 to heat up the high-voltage central electrode 6.

[0044] In the instant embodiment 2, the spark discharge current measurement module 3 consists of the DC sensor 30 and its control circuit. The DC sensor 30 is arranged beside the tested spark plug 5, being connected to the real-time controller 20. The DC sensor 30 measures the spark discharge current amplitude and feedback the measurement results to the real-time controller 20.

[0045] In the instant embodiment 2, the temperature detection module 4 includes the temperature measurement module 40 for the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5, and the thermocouple temperature measurement system 70 for the constant-temperature water jacket cooling chamber 50. The temperature measurement module 40 is placed beside the tested spark plug 5, with the connection to the real-time controller 20, thereby to measure the temperatures of the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5, and feedback the temperatures to the real-time controller 20. The thermocouple temperature measurement system 70 is arranged inside the constant-temperature water jacket cooling chamber 50, to real time measure the chamber body temperature and feedback the results to the real-time controller 20.

[0046] During the spark plug heat rating measurement process, the heat ratings of spark plugs with different ceramic insulator structures are evaluated by the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators of the spark plugs. Different spark plugs are installed in the spark plug heat rating measurement system 9 with spark discharge current active heating through a torque of 30 Nm. The claimed method of measuring the heat ratings of the spark plugs through the temperate changes of the high-voltage central electrodes and the surrounding ceramic insulators is to measure the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators under the same spark gap energy condition, through real time controlling of the spark discharge current amplitude.

[0047] The claimed method of measuring the heat ratings of the spark plugs through the temperate changes of the high-voltage central electrodes and the surrounding ceramic insulators is to calculate the instantaneous heating powers of the spark plugs by measuring the discharge voltages at the high-voltage terminals of the spark plugs and the discharge current. The constant spark discharge current control system 10 is used to real time adjust the discharge current levels to make sure the heating powers of different spark plugs during the heating process are the same. With different heating durations, the high-voltage central electrodes and the surrounding ceramic insulators of different spark plugs can reach the same temperature. The heat ratings of the spark plugs can be evaluated by measuring the temperature rising curves of the high-voltage central electrodes and the surrounding ceramic insulators during the heating process.

Embodiment 3

[0048] The instant embodiment 3 has the same measurement principle as embodiment 1 and embodiment 2, but uses different measurement methods. In the instant embodiment 3, the spark plug heat rating measurement system based on spark discharge current active heating includes the constant spark discharge current control module 2, the real-time control module 1, the spark discharge current measurement module 3, the temperature measurement module 4, and the tested spark plug 5. The tested spark plug 5 is installed in the constant-temperature water jacket cooling chamber 50. The constant-temperature water jacket cooling chamber 50 is cooled by the cooler 60. The temperature of the chamber 50 is controlled by the real-time control module 1 to be constant at 0° C. or 80° C., wherein the real-time control module 1 consists of the real-time controller 20 and its control circuit. The real-time control module 1 is used to monitor the spark discharge current amplitude and real time control the output discharge current from the constant spark discharge current control module 2.

[0049] In the instant embodiment 3, the constant spark discharge current control module 2 consists of the constant spark discharge current control system 10 and its control circuit. The constant spark discharge current control system 10 is connected to the high-voltage terminal 8 of the tested spark plug 5 and the real-time controller 20 respectively. The constant spark discharge current control module 2 provides dynamically controlled spark discharge current to the tested spark plug 5 to heat up the high-voltage central electrode 6.

[0050] In the instant embodiment 3, the spark discharge current measurement module 3 consists of the DC sensor 30 and its control circuit. The DC sensor 30 is arranged beside the tested spark plug 5, with the connection to the real-time controller 20. The DC sensor 30 measures the spark discharge current amplitude and feedback the measurement results to the real-time controller 20.

[0051] In the instant embodiment 3, the temperature detection module 4 includes the temperature measurement module 40 for the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5, and the thermocouple temperature measurement system 70 for the constant-temperature water jacket cooling chamber 50. The temperature measurement module 40 is placed beside the tested spark plug 5, with the connection to the real-time controller 20, thereby to measure the temperatures of the high-voltage central electrode 6 and the surrounding ceramic insulator 80 of the tested spark plug 5, and feedback the temperatures to the real-time controller 20. The thermocouple temperature measurement system 70 is arranged inside the constant-temperature water jacket cooling chamber 50, to real time measure the chamber body temperature and feedback the results to the real-time controller 20.

[0052] During the spark plug heat rating measurement process, the heat ratings of spark plugs with different ceramic insulator structures are evaluated by the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators of the spark plugs. Different spark plugs are installed in the spark plug heat rating measurement system 9 with spark discharge current active heating through a torque of 30 Nm. The claimed method of measuring the heat ratings of the spark plugs through the temperate changes of the high-voltage central electrodes and the surrounding ceramic insulators is to measure the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators under the same spark gap energy condition, through real time controlling of the spark discharge current amplitude.

[0053] The claimed method of measuring the heat ratings of the spark plugs through the temperate changes of the high-voltage central electrodes and the surrounding ceramic insulators is to heat the high-voltage central electrodes and the surrounding ceramic insulators of the spark plugs by the real-time controlled spark discharge current. The high-voltage central electrodes and the surrounding ceramic insulators of different spark plugs can be heated to the same temperature through different heating powers or heating durations. Once the temperatures reach the same level, the heating process is cut off, letting the spark plugs cool down naturally. The temperature profiles during the cooling process are recorded, as shown in FIG. 5 and FIG. 6. Since the heat ratings of the spark plugs represent the heat dissipation capability of the high-voltage central electrodes and the surrounding ceramic insulators, the spark plugs with different heat ratings will have different temperature curves during the cooling process. Therefore, the temperature curves of the cooling process can be used as the parameters to evaluate the heat ratings of different spark plugs.

[0054] The foregoing description of methods and embodiments of the invention has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise steps and/or forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The use of “above,” “below,” “front,” “back,” or “middle” and variations thereof herein is for the purpose of description and should not be regarded as limiting. The structure, ratio, and size shown in the attached drawings are used to help understanding of the present invention and should not be regarded as limiting. It is intended that the scope of the invention and all equivalents be defined by the claims appended hereto. The specific value of torque for the spark plug mounting is not meant to fix the mounting torque, but to emphasis same torque should be used among various spark plugs to guarantee reliable heat transfer path from spark plug to mounting block. Inconsistency in mounting torque for different spark plugs will affect the heat rating measurement.

[0055] Industry Application Value

[0056] The present invention uses a special-designed spark discharge current active control circuit to realize a long and stable spark discharge process, with real time and precise adjustment of the discharge current. The present invention uses the spark discharge current to heat up the high-voltage central electrode from the inside of the spark plug. With the precise control of the spark gap energy, the temperature changes of the high-voltage central electrodes and the surrounding ceramic insulators of different spark plugs are used to evaluate the heat ratings of the spark plugs. As compared with the conventional spark plug heat rating measurement method which utilizes a specific engine to heat spark plug for measuring the heat rating of spark plug, the spark plug heat rating measurement method disclosed in present invention requires much simpler experimental facilities, with shorter experimental time, and higher experimental repeatability and controllability. The present invention does not rely on any engine tests, thus, simplifies the measurement system, with less test parameters to be precisely controlled and shorter experimental durations, thereby, requires lower test costs and has higher efficiency.