Pre-ignition suppression control method and in-cylinder direct injection hydrogen fuel nozzle

Abstract

The invention discloses a preignition suppression control method, relates to power machinery, and solves the technical problem that preignition occurs due to the fact that control protection cannot be carried out because an existing ECU (Electronic Control Unit) cannot monitor the temperature of a spraying part of a nozzle head. The method comprises the following steps: installing a temperature sensor and a cooling water valve at a spraying part of a nozzle head; setting sampling periods and a temperature threshold value, acquiring a plurality of temperature peak values of the nozzle head in the sampling periods, and judging the preignition state of the engine according to the temperature peak values and the temperature threshold value; when it is judged that the preignition state is the moderate continuous preignition state, a first preignition suppression strategy is triggered; and when it is judged that the preignition state is the severe continuous preignition state, a second preignition suppression strategy is triggered. The invention further discloses the in-cylinder direct hydrogen injection fuel nozzle. High-power and high-reliability operation of the hydrogen internal combustion engine is guaranteed.

Description

Technical Field

[0001] This invention relates to power machinery, and more specifically, to a method for suppressing pre-ignition and a direct-injection hydrogen fuel nozzle. Background Technology

[0002] Hydrogen internal combustion engines are characterized by rapid flame propagation and low ignition energy. Under high load and high boost conditions, they are highly susceptible to abnormal combustion problems such as pre-ignition and knocking. Such pre-ignition can lead to serious issues such as a sudden increase in cylinder pressure, overheating and burning of the nozzle, and damage to the engine structure. Conventional direct-injection hydrogen fuel injectors cannot monitor the temperature of the nozzle tip in real time, and the ECU cannot identify nozzle overheating and pre-ignition. Therefore, it is impossible to implement real-time control and protection. Once pre-ignition occurs, it can easily damage the nozzle and the engine, severely limiting the high-power and high-reliability operation of hydrogen internal combustion engines. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a pre-ignition suppression and control method and an in-cylinder direct injection hydrogen fuel nozzle, thereby solving the technical problem that the existing ECU cannot monitor the temperature of the injection part of the nozzle head, which leads to the inability to carry out control and protection, resulting in pre-ignition.

[0004] The pre-ignition suppression control method of the present invention comprises: installing a temperature sensor and a cooling water valve at the injection site of the nozzle head; setting a sampling period and a temperature threshold, acquiring the temperature peak value of the nozzle head within multiple sampling periods, and determining the pre-ignition state of the engine based on the temperature peak value and the temperature threshold; when the pre-ignition state is determined to be a moderate continuous pre-ignition state, triggering a first pre-ignition suppression strategy; and when the pre-ignition state is determined to be a severe continuous pre-ignition state, triggering a second pre-ignition suppression strategy.

[0005] To further improve the method, the method for determining the pre-ignition state of the engine based on the temperature peak and temperature threshold is as follows: set the pre-ignition count value with an initial value of zero, and when the temperature peak is greater than or equal to the temperature threshold, it is determined that pre-ignition has occurred and the pre-ignition count value is incremented by one.

[0006] The instantaneous temperature change rate between the current sampling period and the previous sampling period is obtained based on the temperature peak value. The instantaneous temperature change rate is compared with a preset instantaneous temperature change rate threshold. When the instantaneous temperature change rate is greater than the instantaneous temperature change rate threshold, a preliminary pre-ignition suppression strategy is executed. The peak execution temperature of the nozzle head during the sampling period after the execution of the preliminary pre-ignition suppression strategy is obtained. When the peak execution temperature is less than the temperature threshold, the pre-ignition state is determined to be an occasional pre-ignition, and the pre-ignition count value is cleared to zero. When the pre-ignition count value is greater than or equal to the preset first count value, the peak execution temperature is greater than or equal to the temperature threshold, and the instantaneous temperature change rate is less than the instantaneous temperature change rate threshold, the pre-ignition state is determined to be a moderate continuous pre-ignition state. When the pre-ignition count value is greater than or equal to the preset second count value, the peak execution temperature is greater than or equal to the temperature threshold, and the instantaneous temperature change rate is less than the instantaneous temperature change rate threshold, the pre-ignition state is determined to be a severe continuous pre-ignition state.

[0007] Furthermore, the preliminary pre-ignition suppression strategy is as follows: The ignition time delay value and injection time delay value are calibrated based on the temperature peak value. The preset initial ignition time is delayed based on the ignition time delay value, and the preset initial injection time is delayed based on the injection time delay value.

[0008] Furthermore, the first pre-ignition suppression strategy involves opening the cooling water valve to spray coolant onto the nozzle head to cool it down.

[0009] Furthermore, the second pre-ignition suppression strategy involves opening the cooling water valve, cutting off the nozzle injection, and shutting down the engine.

[0010] An in-cylinder direct injection hydrogen fuel nozzle for implementing the above-mentioned pre-ignition suppression control method, the in-cylinder direct injection hydrogen fuel nozzle comprising, A temperature sensor is installed at the spraying part of the nozzle head to obtain the temperature of the nozzle head and output a temperature signal to the ECU. A cooling water valve is installed at the spraying part of the nozzle head and connected to the engine coolant line through a pipe. It is used to spray coolant at the spraying part of the nozzle head to cool it down.

[0011] As a further improvement, the cooling water valve is connected to the engine coolant line via a pipe, the temperature sensor is electrically connected to the ECU, and the ECU is electrically connected to the controller of the cooling water valve.

[0012] Beneficial effects The advantages of this invention are: This invention installs a temperature sensor and a cooling water valve at the injection point of the nozzle head; acquires the temperature peak value of the nozzle head within multiple sampling periods, and determines the pre-ignition state of the engine based on the temperature peak value and temperature threshold; when the pre-ignition state is determined to be a moderate continuous pre-ignition state, a first pre-ignition suppression strategy is triggered; when the pre-ignition state is determined to be a severe continuous pre-ignition state, a second pre-ignition suppression strategy is triggered; thereby achieving real-time detection of the temperature at the injection point of the nozzle head, thus identifying nozzle overheating and pre-ignition occurrence, and implementing real-time control and protection to avoid pre-ignition and ensure high-power, high-reliability operation of the hydrogen internal combustion engine. Attached Figure Description

[0013] Figure 1 This is a flowchart of the pre-ignition suppression and control method of the present invention; Figure 2 This is a simplified diagram of the overall structure of the pre-ignition suppression control system of the present invention.

[0014] Among them: 1-temperature sensor, 2-ECU, 3-actuator, 4-nozzle, 5-cooling water valve, 6-internal combustion engine. Detailed Implementation

[0015] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0016] See Figures 1-2 The pre-ignition suppression and control method of the present invention, such as Figure 1 As shown, the method involves installing a temperature sensor 1 and a cooling water valve 5 at the spray position of the nozzle 4. The ECU 2 receives the temperature signal from the nozzle head output by the temperature sensor 1, sets the sampling period and temperature threshold, acquires the temperature peak value (T1, in °C) of the nozzle head within multiple sampling periods, and determines the pre-ignition state of the engine based on the temperature peak value and temperature threshold.

[0017] The method for determining the pre-ignition status of an engine based on temperature peaks and temperature thresholds is to set a pre-ignition count value with an initial value of zero. When the peak temperature is less than the temperature threshold, it is determined that there is no pre-ignition phenomenon, the coolant valve 5 remains in the initial closed state, the engine runs normally, and performs normal ignition and injection.

[0018] When the temperature peak is greater than or equal to the temperature threshold, it is determined that pre-ignition has occurred and the pre-ignition count value is incremented by one.

[0019] Calculate the instantaneous temperature change rate (A, in °C / s) between the current sampling period and the previous sampling period based on the temperature peak value. The expression for calculating the instantaneous temperature change rate is: ; Where A is the instantaneous temperature change rate, ΔT1 is the difference between the temperature peak value of the current sampling period and the temperature peak value of the previous sampling period, and Δt is the time elapsed in one sampling period.

[0020] The instantaneous temperature change rate is compared with a preset instantaneous temperature change rate threshold. In this embodiment, the instantaneous temperature change rate threshold is 100℃ / s, and this instantaneous temperature change rate threshold can be calibrated based on the temperature peak value.

[0021] When the instantaneous temperature change rate exceeds the instantaneous temperature change rate threshold, a preliminary pre-ignition suppression strategy is executed.

[0022] The initial pre-ignition suppression strategy is as follows: The ignition timing retardation and injection timing retardation values ​​are calibrated based on the peak temperature. The preset initial ignition timing is then delayed based on the ignition timing retardation value, and the preset initial injection timing is delayed based on the injection timing retardation value. The calibration basis for delayed ignition and delayed injection is: T1 < 450℃. This is achieved by reducing the in-cylinder combustion temperature to improve the reduction of nozzle temperature, and is determined through experimental testing and analysis.

[0023] The peak execution temperature of the nozzle head during the sampling period after the initial pre-ignition suppression strategy is obtained. When the peak execution temperature is less than the temperature threshold, the pre-ignition state is determined to be occasional pre-ignition, and the pre-ignition count value is cleared to zero.

[0024] When the pre-ignition count value is greater than or equal to the preset first count value, the peak execution temperature is greater than or equal to the temperature threshold, and the instantaneous temperature change rate is less than the instantaneous temperature change rate threshold, the pre-ignition state is determined to be a moderate continuous pre-ignition state.

[0025] When the pre-ignition state is determined to be a moderate continuous pre-ignition state, the first pre-ignition suppression strategy is triggered. The first pre-ignition suppression strategy is to open the cooling water valve 5 to spray coolant onto the nozzle to cool it down. The opening degree of the cooling water valve 5 is a fixed opening degree.

[0026] When the pre-ignition count value is greater than or equal to the preset second count value, the peak execution temperature is greater than or equal to the temperature threshold, and the instantaneous temperature change rate is less than the instantaneous temperature change rate threshold, the pre-ignition state is determined to be a severe continuous pre-ignition state.

[0027] When the pre-ignition state is determined to be a severe and continuous pre-ignition state, the second pre-ignition suppression strategy is triggered. The second pre-ignition suppression strategy involves opening the cooling water valve 5, cutting off the injection of nozzle 4, and shutting down the engine to reduce the load, thereby protecting the engine and nozzles. This identifies nozzle overheating and pre-ignition occurrence, and implements real-time control and protection to avoid pre-ignition and ensure the high-power, high-reliability operation of the hydrogen internal combustion engine.

[0028] like Figure 2 As shown, an in-cylinder direct injection hydrogen fuel nozzle for implementing the above-mentioned pre-ignition suppression control method includes, Temperature sensor 1, integrating a CAN communication module, is installed in the spray area of ​​nozzle 4 to acquire the temperature of the nozzle head and output a temperature signal. This enables real-time detection of the temperature of the spray area at the nozzle head.

[0029] Cooling water valve 5 is installed in the spray area of ​​the nozzle head 4 and connected to the engine coolant line through a pipe. It is used to spray coolant to cool the nozzle head.

[0030] Cooling water valve 5 is connected to the engine coolant line via a pipe, temperature sensor 1 is electrically connected to ECU 2, and ECU 2 is electrically connected to the controller of cooling water valve 5.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for suppressing and controlling pre-ignition, characterized in that, The method involves installing a temperature sensor (1) and a cooling water valve (5) at the spray position of the nozzle (4); setting a sampling period and a temperature threshold; obtaining the temperature peak value of the nozzle head within multiple sampling periods; and determining the pre-ignition state of the engine based on the temperature peak value and the temperature threshold. When the pre-ignition state is determined to be a moderate continuous pre-ignition state, the first pre-ignition suppression strategy is triggered. When the pre-ignition state is determined to be a severe continuous pre-ignition state, the second pre-ignition suppression strategy is triggered.

2. The pre-ignition suppression and control method according to claim 1, characterized in that, The method for determining the pre-ignition state of the engine based on the temperature peak and temperature threshold is as follows: set the pre-ignition count value with an initial value of zero, and when the temperature peak is greater than or equal to the temperature threshold, it is determined that pre-ignition has occurred and the pre-ignition count value is incremented by one. The instantaneous temperature change rate between the current sampling period and the previous sampling period is obtained based on the temperature peak value. The instantaneous temperature change rate is compared with a preset instantaneous temperature change rate threshold. When the instantaneous temperature change rate is greater than the instantaneous temperature change rate threshold, a preliminary pre-ignition suppression strategy is executed. The peak execution temperature of the nozzle head during the sampling period after the execution of the preliminary pre-ignition suppression strategy is obtained. When the peak execution temperature is less than the temperature threshold, the pre-ignition state is determined to be an occasional pre-ignition, and the pre-ignition count value is cleared to zero. When the pre-ignition count value is greater than or equal to the preset first count value, the peak execution temperature is greater than or equal to the temperature threshold, and the instantaneous temperature change rate is less than the instantaneous temperature change rate threshold, the pre-ignition state is determined to be a moderate continuous pre-ignition state. When the pre-ignition count value is greater than or equal to the preset second count value, the peak execution temperature is greater than or equal to the temperature threshold, and the instantaneous temperature change rate is less than the instantaneous temperature change rate threshold, the pre-ignition state is determined to be a severe continuous pre-ignition state.

3. The pre-ignition suppression and control method according to claim 2, characterized in that, The preliminary pre-ignition suppression strategy is as follows: The ignition time delay value and injection time delay value are calibrated based on the temperature peak value. The preset initial ignition time is delayed based on the ignition time delay value, and the preset initial injection time is delayed based on the injection time delay value.

4. The pre-ignition suppression and control method according to claim 1, characterized in that, The first pre-ignition suppression strategy is to open the cooling water valve (5) to spray coolant onto the head of the nozzle (4) to cool it down.

5. The pre-ignition suppression and control method according to claim 1, characterized in that, The second pre-ignition suppression strategy is to open the cooling water valve (5), cut off the injection of the nozzle (4), and shut down the engine.

6. A direct-injection hydrogen fuel nozzle for implementing the pre-ignition suppression control method according to any one of claims 1-5, characterized in that, The in-cylinder direct injection hydrogen fuel nozzle includes, Temperature sensor (1) is installed at the spraying part of the nozzle (4) head to obtain the temperature of the nozzle head and output a temperature signal to the ECU (2); Cooling water valve (5) is installed at the spraying part of the nozzle (4) head and connected to the engine coolant pipeline through a pipe. It is used to spray coolant at the spraying part of the nozzle (4) head to cool it down.

7. The in-cylinder direct injection hydrogen fuel nozzle according to claim 6, characterized in that, The cooling water valve (5) is connected to the engine coolant pipeline through a pipe, the temperature sensor (1) is electrically connected to the ECU (2), and the ECU (2) is electrically connected to the controller of the cooling water valve (5).

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