Engine in-cylinder pressure detection method

Abstract

The present application relates to the technical field of diesel engine, and provides an engine in-cylinder pressure detection method and system, the engine in-cylinder pressure detection method comprises the synchronous acquisition of each channel cylinder pressure signal;The range conversion and processing are carried out to each channel cylinder pressure signal, and the actual cylinder pressure value of each channel is obtained;The target curve is obtained by calculating a plurality of actual cylinder pressure values, and the in-cylinder pressure combustion characteristic value is determined according to the target curve.The present application also provides an engine in-cylinder pressure detection system.Using the above engine in-cylinder pressure detection method, each channel cylinder pressure signal can be synchronously collected, the target curve is synchronized with the collection process, and the target curve is also completed when the collection is completed.The accurate target curve can be obtained by real-time collection, the combustion characteristic value obtained according to the target curve is more accurate, and the combustion characteristic value is consistent with the real running state in the cylinder.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of diesel engine, in particular to an engine in-cylinder pressure detection method and system. BACKGROUND

[0002] The engine is limited by a large number of internal structures and mutual correlation, and the working condition is very harsh, so the probability of failure is relatively large.

[0003] The engine in-cylinder combustion state can directly reflect the working condition of the engine in-cylinder, and the existing scheme mostly adopts a prediction simulation method to predict the in-cylinder combustion state, that is, a predicted in-cylinder pressure curve is obtained in advance, and then the real in-cylinder pressure curve is obtained by comparing one or more actual characteristic values in the cylinder with the pressure curve, and then the combustion characteristic value is obtained. Although this method saves the pressure of computer data calculation, the data obtained is the data after the cycle ends, on the one hand, it cannot reflect the in-cylinder pressure change process in real time, on the other hand, the matching accuracy is not high, so that the feedback data reliability is low. SUMMARY

[0004] An object of the present application is to provide an engine in-cylinder pressure detection method, which can solve the technical problems of low cylinder pressure detection data precision and inability to reflect the in-cylinder running state in real time in the prior art.

[0005] In a first aspect, the present application provides an engine in-cylinder pressure detection method, comprising: synchronously collecting cylinder pressure signals of each channel;

[0006] Converting the cylinder pressure signals of each channel to obtain actual cylinder pressure values of each channel;

[0007] Obtaining a target curve by calculating a plurality of actual cylinder pressure values, and determining an in-cylinder pressure combustion characteristic value according to the target curve.

[0008] In an embodiment, when synchronously collecting cylinder pressure signals of each channel, the method further comprises:

[0009] Synchronously collecting a rotation angle signal; wherein the rotation angle signal comprises a pulse signal and a key signal, and the cylinder pressure signal cycle start identifier and cycle end identifier of each channel are obtained according to the number of points, the angular resolution and the cylinder pressure intercept bias angle of the key signal currently identified.

[0010] In an embodiment, the target curve comprises a cylinder pressure curve, a heat release rate curve and a pressure rise rate curve.

[0011] In an embodiment, the target curve is obtained by calculating a plurality of actual cylinder pressure values, comprising:

[0012] In the process of obtaining the cylinder pressure curve, the maximum pressure is calculated and the position of the maximum pressure is recorded; in the process of obtaining the heat release rate curve, the heat release rate is calculated and the cumulative heat release is recorded; in the process of obtaining the pressure rise rate curve, the maximum pressure rise rate is calculated and the position of the maximum pressure rise rate is recorded.

[0013] In one embodiment, the combustion characteristic values include: maximum pressure phase, maximum pressure rise rate phase, combustion start point, combustion center and combustion end point; wherein,

[0014] After identifying the end-of-cycle identifier of each channel, the maximum pressure phase is determined according to the recorded position of the maximum pressure, the maximum pressure rise rate phase is determined according to the recorded position of the pressure rise rate, and the combustion start point, the combustion center and the combustion end point are obtained according to the heat release rate curve and the pressure rise rate curve.

[0015] In one embodiment, after determining the in-cylinder pressure combustion characteristic values according to the target curve, the method further includes:

[0016] Outputting the combustion characteristic values to an external reference.

[0017] In a second aspect, the present application provides an in-cylinder pressure detection system of an engine, comprising:

[0018] A collection module, which synchronously collects cylinder pressure signals of each channel;

[0019] A conversion module, which performs range conversion and processing on the cylinder pressure signals of each channel to obtain actual cylinder pressure values of each channel;

[0020] A calculation module, which obtains a target curve by calculating a plurality of actual cylinder pressure values, and determines in-cylinder pressure combustion characteristic values according to the target curve.

[0021] In one embodiment, the system further includes an output module, which is configured to output the combustion characteristic values to an external reference.

[0022] In a third aspect, the present application provides an electronic device, comprising: a processor and a memory, wherein the memory stores programs or instructions executable on the processor, and the programs or instructions are executed by the processor to implement the steps of the engine in-cylinder pressure detection method as described above.

[0023] In a fourth aspect, the present application provides a readable storage medium, comprising: programs or instructions stored on the readable storage medium, and the programs or instructions are executed by a processor to implement the steps of the engine in-cylinder pressure detection method as described above.

[0024] The engine in-cylinder pressure detection method can synchronously collect the cylinder pressure signals of each channel, the target curve is synchronized with the collection process, and the target curve is completed when the collection is completed, so that the accurate target curve can be obtained through real-time collection, the combustion characteristic value obtained according to the target curve is more accurate, and the combustion characteristic value is consistent with the real running state in the cylinder. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and other features, properties, and advantages of the present application will become more apparent by referring to the following description in conjunction with the accompanying drawings in which:

[0026] Figure 1 is a flow chart of an exemplary engine in-cylinder pressure detection method according to the present application;

[0027] Figure 2 is a schematic diagram of an exemplary engine in-cylinder pressure detection system according to the present application;

[0028] Figure 3 is a structural schematic diagram of an electronic device according to the present application. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with the specific embodiments and drawings, and more details are set forth in the following description in order to fully understand the present application, but the present application can certainly be implemented in various other ways different from the description, and those skilled in the art can make similar generalizations and deductions according to the actual application without departing from the scope of the present application, so the protection scope of the present application should not be limited by the content of the specific embodiments.

[0030] Reference Figure 1 The engine in-cylinder pressure detection method comprises:

[0031] S110, synchronously collecting cylinder pressure signals of each channel.

[0032] Each cylinder of the engine corresponds to one channel, and the engine comprises 20 channels, corresponding to cylinder pressure signals comprising 20 cylinders. The present application can realize collection of each cylinder per cycle, and the collected data is associated with the real running state in the cylinder, so that the accuracy is higher.

[0033] In one embodiment, when the cylinder pressure signals of each channel are synchronously collected, the rotation angle signal is also synchronously collected. The rotation angle signal comprises a pulse signal and a key signal, and the cycle start identifier and the cycle end identifier of the cylinder pressure signal of each channel are obtained according to the number of points, the angle resolution, and the cylinder pressure interception bias angle of the identified key signal.

[0034] The acquisition of the cylinder pressure signal and the acquisition of the rotation angle signal are synchronous, the number of points of the currently identified key belief signal acquisition is recorded, and then the angle resolution and the cylinder pressure intercept bias angle are combined to mark the cycle start mark and the cycle end mark of each cylinder pressure signal, so that the acquisition and analysis of each cycle data are realized.

[0035] Each output data corresponds to a cylinder pressure physical quantity signal, and the cylinder pressure physical quantity signal collected at this time is a current communication signal, but is not limited to a current communication signal, and can also be a voltage signal or an optical signal, as long as it can play a signal transmission role. After receiving the current communication signal, the current communication signal needs to be range converted to convert the current physical quantity signal to an engineering point value. After obtaining the engineering point value, the cylinder pressure value after baseline correction is obtained according to the baseline correction algorithm, which corresponds to the real cylinder pressure value at the current time point and also corresponds to the actual cylinder pressure value.

[0036] During each cycle of each cylinder, the output of the cylinder pressure value is synchronized with the cycle, so that the cylinder pressure value change process is also collected, and the real-time running state in the cylinder is reflected, so that the collected data is more related to the real running state in the cylinder and has higher fitting degree.

[0037] S130, a target curve is obtained by calculating a plurality of actual cylinder pressure values, and a cylinder pressure combustion characteristic value is determined according to the target curve.

[0038] In one embodiment, the target curve includes a cylinder pressure curve, a heat release rate curve, and a pressure rise rate curve.

[0039] When the cylinder pressure curve is obtained, the maximum pressure is calculated synchronously and the position of the maximum pressure is recorded; when the heat release rate curve is obtained, the heat release rate is calculated synchronously and the cumulative heat release is recorded; when the pressure rise rate curve is obtained, the maximum pressure rise rate is calculated synchronously and the position of the maximum pressure rise rate is recorded.

[0040] The generation of the cylinder pressure curve, the heat release rate curve, and the pressure rise rate curve is synchronized with the cycle process, and the cylinder pressure curve, the heat release rate curve, and the pressure rise rate curve are also completed synchronously at the end of the cycle in the cylinder, so that the acquisition of the maximum pressure, the position of the maximum pressure, the heat release rate, the cumulative heat release, the maximum pressure rise rate, and the position of the maximum pressure rise rate all correspond to the actual state in the cylinder, the target curve can reflect the real combustion state in the cylinder, and the obtained data has higher accuracy.

[0041] The combustion characteristic values include a maximum explosion pressure phase, a maximum pressure rise rate phase, a combustion start point, a combustion center, and a combustion end point.

[0042] Because the cylinder pressure curve, the heat release rate curve, and the pressure rise rate curve are synchronized with the in-cylinder cycle, the target curve obtained is more consistent with the in-cylinder combustion state, and the acquisition of the characteristic values is more accurate.

[0043] After the pressure combustion characteristic values are determined, the combustion characteristics are output to an external reference. The external reference corresponds to a third-party system, a client system, etc., which is not limited here.

[0044] In an embodiment, the engine in-cylinder pressure detection system can be connected to the ARM unit through AXI communication. The data obtained by the engine in-cylinder pressure detection system can be sent to the ARM unit through the AXI bus. The above sending method is repeated until the end of each cylinder cycle is identified, and the next cycle repeats the above sending method.

[0045] The data sent to the ARM is the combustion characteristic value, which includes the maximum explosion pressure phase, the maximum pressure rise rate phase, the combustion start point, the combustion center, and the combustion end point. After the end of each cycle is identified, the maximum explosion pressure phase is determined according to the recorded maximum explosion pressure position, the maximum pressure rise rate phase is determined according to the recorded pressure rise rate position, and the combustion start point, the combustion center, and the combustion end point are obtained according to the heat release rate curve and the pressure rise rate curve.

[0046] The ARM unit includes a CAN communication subunit, a TCP / IP communication subunit, and a data storage subunit. The CAN communication subunit is used to send the combustion characteristic values of any cylinder cycle to a third-party system according to the CAN communication protocol before the next cylinder interrupt signal is generated after the combustion characteristic values of any cylinder cycle are read on the ARM end. The communication method is not limited to CAN communication.

[0047] The TCP / IP communication is used to send the target curve and the combustion characteristic values of any cylinder cycle to a client according to the TCP / IP communication protocol before the next cylinder interrupt signal is generated after the target curve and the combustion characteristic values of any cylinder cycle are read on the ARM end. At the same time, the ARM end receives configuration parameters from the client through TCP / IP communication to establish communication connection between the engine in-cylinder pressure detection system and the client.

[0048] The data storage subunit is used to store the target curve and the combustion characteristic values of any cylinder cycle in a storage card before the next cylinder interrupt signal is generated after the target curve and the combustion characteristic values of any cylinder cycle are read, for subsequent fault analysis.

[0049] In one embodiment, to ensure data processing and real-time communication, the ARM unit adopts a dual-core operation mode, and the AXI data communication, eigenvalue and a small part of the calculation function are performed in CPU1, and the CAN communication and TCP / IP communication function are performed in CPU2. In other embodiments, the ARM unit is not limited to dual-core operation, and the task allocation in each core can also be in other ways, which is not limited here.

[0050] In one embodiment, the present application can realize the collection of the cylinder pressure curve, heat release rate curve, pressure rise rate curve, pressure rise rate curve data of each cylinder, computer communication display within 2.4ms at a speed of 2500rpm, while obtaining the combustion characteristic parameters such as the position of the explosion pressure, the phase of the explosion pressure, the maximum pressure rise rate, the heat release rate point, the effective pressure, the cycle variation, and the unevenness of each cylinder, realizing the collection and combustion analysis of the in-cylinder pressure of each cylinder of a 20-cylinder engine at 2500rpm per cycle. The collected data is more consistent with the in-cylinder combustion state, and the data precision is higher.

[0051] Please refer to Figure 2 The present application also provides an engine in-cylinder pressure detection system, comprising an acquisition module, a conversion module and a calculation module, the acquisition module synchronously acquires cylinder pressure signals of each channel; the conversion module performs range conversion and processing on the cylinder pressure signals of each channel to obtain actual cylinder pressure values of each channel; the calculation module obtains a target curve by calculating a plurality of actual cylinder pressure values, and determines the in-cylinder pressure combustion characteristic value according to the target curve.

[0052] It also includes an output module for outputting the combustion characteristic value to an external reference.

[0053] In one embodiment, the acquisition module sends the acquired cylinder pressure signals of each channel to the conversion module, the conversion module processes the cylinder pressure signals and obtains actual cylinder pressure values, the actual cylinder pressure values obtain a target curve under the processing of the calculation module, and the in-cylinder pressure combustion value is determined according to the target curve.

[0054] The acquisition module acquires current signals, and the conversion module is used to receive the acquired cylinder pressure physical quantity signals, convert the physical quantity signals to engineering values according to the range conversion relationship between the physical points and the engineering points, obtain the engineering values, filter the in-cylinder engineering values according to the filtering algorithm to obtain the filtered cylinder pressure values, the filtered cylinder pressure values correspond to the real in-cylinder pressure values, and then the acquired signals and the obtained cylinder pressure values correspond to the real-time combustion state in the cylinder, eliminating the deviation caused by model matching in the prior art.

[0055] The calculation module comprises a plurality of curve calculation subunits, each corresponding to an in-cylinder passage. After each output of an actual cylinder pressure value in each passage of each cylinder, the cylinder curve calculation subunits synchronously calculate the cylinder pressure curve, the heat release rate curve and the pressure rise rate curve based on the newly received cylinder pressure value, output three curve points of the cylinder pressure, the heat release rate and the pressure rise rate in each calculation clock, and ensure the synchronous output of the curve subunits and the conversion module. When the cylinder pressure curve points are obtained, the calculation of the maximum pressure and the recording of the position of the maximum pressure are synchronously performed; when the heat release rate curve is obtained, the calculation of the heat release rate and the recording of the cumulative heat release are synchronously performed; and when the pressure rise rate curve is obtained, the calculation of the maximum pressure rise rate and the recording of the position of the maximum pressure rise rate are synchronously performed.

[0056] In one embodiment, the engine in-cylinder pressure detection system can be connected with the ARM unit through AXI communication. The data obtained by the engine in-cylinder pressure detection system can be sent to the ARM unit through the AXI bus, and the sending is repeated in this way until the end-of-cycle identifier of each cylinder is identified, and the next cycle repeats the above sending method.

[0057] The data sent to the ARM is the combustion characteristic value, which includes the maximum explosion pressure phase, the maximum pressure rise rate phase, the combustion start point, the combustion center and the combustion end point. After the end-of-cycle identifier of each passage is identified, the maximum explosion pressure phase is determined according to the recorded maximum explosion pressure position, the maximum pressure rise rate phase is determined according to the recorded pressure rise rate position, and the combustion start point, the combustion center and the combustion end point are obtained according to the heat release rate curve and the pressure rise rate curve.

[0058] The ARM unit comprises a CAN communication subunit, a TCP / IP communication subunit and a data storage subunit. The CAN communication subunit is used to send the combustion characteristic value of each cylinder cycle to a third-party system according to the CAN communication protocol before the next cylinder interruption signal is generated after the combustion characteristic value of any cylinder cycle is read at the ARM end.

[0059] The TCP / IP communication is used to send the target curve and the combustion characteristic value of each cylinder to a client according to the TCP / IP communication protocol before the next cylinder interruption signal is generated after the target curve and the combustion characteristic value of any cylinder cycle are read at the ARM end, and the ARM end receives the configuration parameters from the client through the TCP / IP communication to generate a communication connection between the engine in-cylinder pressure detection system and the client.

[0060] The data storage subunit is used to store the target curve and the combustion characteristic value of any cylinder into a storage card before the next cylinder interruption signal is generated after the target curve and the combustion characteristic value of any cylinder cycle are read, for subsequent fault analysis.

[0061] In one embodiment, to ensure data processing and real-time communication, the ARM unit adopts dual-core operation mode, AXI data communication, eigenvalue and a small part of calculation function are performed in CPU1, and CAN communication and TCP / IP communication function are performed in CPU2. In other embodiments, the ARM unit is not limited to dual-core operation, and the task allocation in each core can also be in other manners, which is not limited herein.

[0062] Please refer to Figure 3 The application further provides an electronic device 900, comprising a processor 901 and a memory 902, the memory 902 stores programs or instructions which can be run on the processor 901, the programs or instructions are executed by the processor 901 to realize the steps of the engine in-cylinder pressure detection method as described above, and achieve the same technical effects, to avoid repetition, which will not be described here.

[0063] Some aspects of the application can be completely executed by hardware, completely executed by software (including firmware, resident software, microcode, etc.), or executed by a combination of hardware and software. The above hardware or software can be referred to as "data block", "module", "engine", "unit", "component" or "system". The processor can be one or more application specific integrated circuits (ASIC), digital signal processors (DSP), digital signal processing devices (DAPD), programmable logic devices (PLD), field programmable gate arrays (FPGA), processors, controllers, microcontrollers, microprocessors or combinations thereof. In addition, aspects of the application can be computer products located in one or more computer readable media, including computer readable program codes.

[0064] The application further provides a readable storage medium, the readable storage medium stores programs or instructions, the programs or instructions are executed by the processor to realize the steps of the engine in-cylinder pressure detection method as described above.

[0065] For example, computer readable media can include, but are not limited to, magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips...), optical disks (e.g., compact disk (CD), digital versatile disk (DVD)...), smart cards, and flash memory devices (e.g., card, stick, key drive...). Computer readable media can also include transitory media such as a transitory signal traveling over a wire or a wireless medium. Computer readable media can further include any medium that is suitable for storing or transmitting instructions for execution by a machine. Computer readable media can include any suitable combination of these or other computer readable media.

[0066] Although the present application has been disclosed in its preferred embodiments with reference to the accompanying drawings, it is not intended to limit the present application thereto, and any modification and change of the present application, which do not depart from the spirit and scope of the present application, will be construed as falling within the scope of the present application. Accordingly, any modification, equivalent change and modification of the above embodiments, which do not depart from the technical concept of the present application, fall within the scope of the present application as defined by the claims.

Claims

1. An engine in-cylinder pressure detecting method characterized by comprising: The method comprises: synchronously collecting cylinder pressure signals of each channel; wherein each cylinder of the engine corresponds to one channel, and the cylinder pressure signal is collected per cylinder per cycle; performing range conversion on the cylinder pressure signals of each channel to obtain actual cylinder pressure values of each channel; calculating a target curve by using the actual cylinder pressure values, and determining an in-cylinder pressure combustion characteristic value according to the target curve; wherein the target curve comprises a cylinder pressure curve, a heat release rate curve, and a pressure rise rate curve; when the cylinder pressure curve is obtained, the maximum pressure is calculated and the position of the maximum pressure is recorded; when the heat release rate curve is obtained, the heat release rate is calculated and the cumulative heat release amount is recorded; and when the pressure rise rate curve is obtained, the maximum pressure rise rate is calculated and the position of the maximum pressure rise rate is recorded; each in-cylinder channel corresponds to a curve calculation subunit, and after each actual cylinder pressure value of each cylinder and each channel is output, the cylinder curve calculation subunit synchronously performs the cylinder pressure curve calculation, the heat release rate curve calculation, and the pressure rise rate curve calculation on the newly received cylinder pressure value, and three curve points of the cylinder pressure, the heat release rate, and the pressure rise rate are output in each calculation clock.

2. The engine in-cylinder pressure detecting method according to claim 1, characterized by, when the cylinder pressure signals of each channel are synchronously collected, the method further comprises: synchronously collecting a rotation angle signal; wherein the rotation angle signal comprises a pulse signal and a key signal, and the cylinder pressure signal cycle start identifier and the cylinder pressure signal cycle end identifier are obtained according to the number of points, the angle resolution, and the cylinder pressure interception bias angle of the currently recognized key signal.

3. The engine in-cylinder pressure detecting method according to claim 1, characterized by, the combustion characteristic value comprises a maximum explosion pressure phase, a maximum pressure rise rate phase, a combustion start point, a combustion center, and a combustion end point; wherein after the cycle end identifier of each channel is recognized, the maximum explosion pressure phase is determined according to the recorded maximum explosion pressure position, the maximum pressure rise rate phase is determined according to the recorded pressure rise rate position, and the combustion start point, the combustion center, and the combustion end point are obtained according to the heat release rate curve and the pressure rise rate curve.

4. The engine in-cylinder pressure detecting method according to claim 1, characterized by, after the in-cylinder pressure combustion characteristic value is determined according to the target curve, the method further comprises: outputting the combustion characteristic value to an external reference.

5. An electronic device, comprising: The method comprises: a processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and the programs or instructions are executed by the processor to implement the steps of the engine in-cylinder pressure detection method according to any one of claims 1-4.

6. A readable storage medium, characterized by, programs or instructions are stored on the readable storage medium, and the programs or instructions are executed by the processor to implement the steps of the engine in-cylinder pressure detection method according to any one of claims 1-4.

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