Rotating speed switching method between idle speed and rated working condition of engine off-line test, test method and system

Abstract

The invention discloses a rotating speed switching method between an idle speed test and a rated working condition of an engine offline test and a test method and system. When the idle speed working condition is switched to the rated working condition, if a throttle valve opening value corresponding to the idle speed working condition is smaller than or larger than a throttle valve required opening value under the rated working condition, the larger value between the idle speed working condition and the throttle valve required opening value is taken; if the throttle valve opening value corresponding to the idling working condition is equal to the throttle valve required opening value under the rated working condition, the throttle valve required opening value is directly taken; and when the rated working condition is switched to the idling working condition, the I integral value of the idling working condition is reset at the moment of triggering the switching state, and the reset value is the corresponding throttle valve required opening value under the rated working condition during switching.

Description

Technical Field

[0001] This invention belongs to the field of gas engine off-line testing. This invention discloses a method for switching engine speed between idle speed and rated operating condition during off-line testing, and an off-line testing method and system including the speed control switching method. Background Technology

[0002] Before leaving the factory, gas engines undergo off-line testing. This off-line testing is the final quality checkpoint in the entire engine manufacturing process. Its purpose is to ensure that each engine 100% meets basic performance, functional, and sealing requirements through a series of rapid, efficient, and standardized tests before it leaves the production line. One part of the off-line testing for gas engines involves testing the coordination between the engine throttle, engine control unit (ECU), and throttle under idle and rated load conditions. The specific testing method involves connecting the engine's output shaft to a hydraulic dynamometer via a coupling, while simultaneously connecting the engine throttle and throttle control knobs to the ECU. Then, tests are performed under rated and idle conditions. Currently, the switching between rated and idle conditions, or between idle and rated conditions, is done directly. However, because the speed difference between the two conditions is relatively large, this leads to significant engine speed fluctuations. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention proposes a method for switching engine speed between idle speed and rated operating condition during engine off-line testing, as well as an off-line testing method and system.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for switching engine speed between idle speed during off-line testing and rated operating conditions, as follows: When switching from idle to rated operating condition, if the throttle opening value corresponding to the idle condition is less than or greater than the throttle opening value required under rated operating condition, the larger value between the two shall be taken; if the throttle opening value corresponding to the idle condition is equal to the throttle opening value required under rated operating condition, the throttle opening value required shall be taken directly. When switching from rated operating condition to idle operating condition, the integral value of I in idle operating condition is reset at the moment the switching state is triggered. The reset value is the throttle opening value required under rated no-load operating condition at the time of switching.

[0005] As a further technical solution, the required throttle opening value under rated operating conditions is obtained by checking the throttle opening when the throttle is turned on. Secondly, the present invention also provides an engine off-line testing method, including idling condition testing and rated condition testing, wherein the speed control switching method between idling condition and rated condition adopts the speed switching method described above.

[0006] As a further technical solution, the engine speed control under idling conditions adopts PID control.

[0007] As a further technical solution, the PID control process is as follows: The engine control unit sends a set speed signal to the engine. At this time, the throttle valve opens, the engine rotates, and the actual speed of the engine is detected in real time. The engine control unit obtains the difference between the actual speed and the set speed, and adjusts the throttle valve opening in real time through the PID controller to realize PID closed-loop control of the engine under idling conditions.

[0008] As a further technical solution, the engine speed control under rated operating conditions is achieved by controlling the throttle opening in accordance with the throttle position.

[0009] As a further technical solution, the method for checking the throttle opening by adjusting the throttle position is as follows: The engine control unit sends a rated speed signal to the engine. At this rated speed, different loads are applied to the engine output via a hydraulic dynamometer. The engine speed will decrease at this time. Then, the throttle opening is continuously adjusted so that the engine speed is always maintained at the rated speed. Thirdly, the present invention also provides a speed switching system between engine off-line testing idle speed and rated operating condition, comprising: The first switching module is configured to take the larger value between the two if the throttle opening value corresponding to the idle condition is less than or greater than the throttle opening value required under the rated condition; and to take the throttle opening value directly if the throttle opening value corresponding to the idle condition is equal to the throttle opening value required under the rated no-load condition. The second switching module is configured to reset the I integral value of the idle condition when switching from the rated operating condition to the idle operating condition. The reset value is the throttle opening value required under the rated operating condition at the time of switching.

[0010] As a further technical solution, the required throttle opening value under rated operating conditions is obtained by checking the throttle opening when the throttle is turned on. Fourthly, the present invention also provides a gas engine off-line testing system, which includes a hydraulic dynamometer, a throttle control knob and an engine control unit; wherein the engine control unit uses the speed switching method between idle speed and rated operating conditions described above when switching speed control between idle speed and rated operating conditions during engine off-line testing.

[0011] The beneficial effects of this invention are as follows: This invention ensures that the engine can smoothly switch between idle and rated operating conditions during offline testing. Specifically, when switching from idle to rated operating conditions, if the throttle opening value corresponding to the idle condition is less than or greater than the required throttle opening value under rated operating conditions, the larger value is taken. If the throttle opening value corresponding to the idle condition is equal to the required throttle opening value under rated operating conditions, the required throttle opening value is directly taken. When switching from rated operating conditions to idle condition, the integral value of the idle condition is reset at the moment the switching state is triggered. The reset value is the required throttle opening value corresponding to the rated no-load condition at the time of switching. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0013] Figure 1 This is a flowchart of the engine speed switching method between idle speed and rated operating condition during the off-line testing of the engine proposed in this invention; Figure 2 MAP diagram for checking throttle opening; Figure 3 This is a schematic diagram of the basic closed-loop control logic for rotational speed. Figure 4 This is a flowchart illustrating the switching process between closed-loop speed control at idle and speed control using throttle opening in rated operating conditions, as described in the embodiment. Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0014] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. Definition: Idle speed control: refers to the process after the engine starts and enters the idle speed control unit, then enters the idle speed condition. The idle speed condition is the condition in which the engine can run normally and there is no external load.

[0015] Throttle position refers to the control of the throttle valve opening when the engine is under load. This control is achieved by adjusting the throttle position to maintain the engine at its rated speed.

[0016] As described in the background section, one of the testing steps in the factory testing of existing gas engines is to test the coordination between the engine throttle, engine control unit (ECU), and throttle under idling and rated load conditions. The specific testing method involves connecting the engine's output shaft to a hydraulic dynamometer via a coupling, while simultaneously connecting the engine throttle and throttle control knobs to the ECU. Then, tests are performed under rated and idling conditions. Currently, the switching between rated and idling conditions, or between idling and rated conditions, is done directly. However, because the speed difference between the two conditions is relatively large, this leads to significant engine speed fluctuations. Example 1 To address the aforementioned technical issues, this embodiment proposes a speed switching method between idle and rated operating conditions during engine off-line testing; specifically, it proposes a method for switching between idle speed closed-loop control and rated operating condition speed control using throttle position and throttle opening adjustment.

[0017] In a typical embodiment of the present invention, such as Figure 1As shown, this embodiment provides a method for switching an engine between idle speed and rated operating conditions, as well as an overall control method including this switching method. The switching method includes switching from idle speed to rated operating conditions and switching from rated operating conditions to idle speed. Because engine testing typically involves first testing at idle speed, then testing at rated operating conditions, and finally unloading from rated operating conditions and returning to idle speed, there are two switching points: one is the switch from idle speed to rated operating conditions, and the other is the switch from rated operating conditions to idle speed. When switching from idle to rated operating condition, if the throttle opening value corresponding to the idle condition is less than or greater than the throttle opening value required under rated operating condition, the larger value between the two is taken. If the throttle opening value corresponding to the idle condition is equal to the throttle opening value required under rated operating condition, the throttle opening value required under rated operating condition is taken directly. When switching from rated operating condition to idle condition, at the moment the switching state is triggered, the I integral value of the idle condition (the I integral value of the PID controller in the engine control unit) is reset. The reset value is the throttle opening value required under rated no-load operating condition at the time of switching.

[0018] The following provides a complete explanation of the idling speed condition, the rated operating condition, and the switching methods between them; Under idling conditions, such as Figure 3 , Figure 4 As shown, a PID closed-loop control method is used to test and control the engine speed and throttle position. The specific control method is as follows: The engine control unit (ECU) sends a set speed signal to the engine. At this time, the throttle opens and the engine starts to rotate. The ECU also monitors the actual engine speed in real time. The ECU obtains the difference between the actual speed and the set speed and adjusts the throttle opening in real time through the PID controller to achieve PID closed-loop control of the engine under idling conditions. Under normal conditions, the engine speed is set to 700 rpm at idle. The engine control unit (ECU) sends a 700 rpm signal to the engine. At this time, the throttle opens and the engine starts to rotate. The ECU also monitors the actual engine speed in real time. The ECU obtains the difference between the actual speed and 700 rpm and adjusts the throttle opening in real time through the PID controller to achieve PID closed-loop control of the engine at idle. At rated speed, such as Figure 2 As shown, the engine speed and throttle opening are tested by checking the throttle position with the throttle. The specific control method is as follows: Specifically, the engine control unit (ECU) sends a rated speed signal to the engine. Under normal circumstances, the engine's rated speed is 1500 rpm. Then, at this rated speed, different loads are applied to the engine output via a hydraulic dynamometer. The engine speed will decrease, and the throttle opening is continuously adjusted to regulate the throttle opening, so that the engine speed is always maintained at 1500 rpm. Throughout the process, the engine, throttle, and other components are tested by applying different loads and continuously adjusting the throttle.

[0019] When switching between the two operating conditions mentioned above, the engine speed will increase directly from 700 rpm at idle to 1500 rpm at rated operating conditions. However, the engine is still under no-load conditions, so the throttle opening remains the value corresponding to 1500 rpm at idle. Let's assume the throttle opening is 5% at this point. After a few seconds, the system will automatically switch to a throttle opening determination method based on throttle input. However, the throttle opening value obtained through this method will be different. Figure 1 The throttle opening value corresponding to a throttle opening of 0 is 6%. Since the two values ​​are different, in order to ensure the stability of engine speed in this embodiment, the system uses a throttle opening value of 6% for control, at which point the engine is relatively stable. Then, a certain amount of load is added to the engine output. Due to the increased load, the engine speed will decrease. At this time, the throttle opening can be adjusted to increase the throttle opening, thereby maintaining the engine speed at 1500 rpm. Then, the throttle is adjusted by continuously adjusting the load.

[0020] If the engine speed increases directly from 700 rpm at idle to 1500 rpm at rated speed, the throttle opening will be 7%. After a few seconds of operation, the system will automatically switch to a throttle opening determination method based on throttle input. However, the throttle opening value obtained through this method will be different from the actual throttle opening value. Figure 1 When the throttle opening is 0, the corresponding throttle opening value is 6%. The system uses a throttle opening value of 7% for control. If the engine speed increases directly from 700 rpm at idle to 1500 rpm at rated speed, the throttle opening will be 6%. After a few seconds of operation, the system will automatically switch to a throttle opening determination method based on throttle input. However, the throttle opening value obtained through this method will be different from the actual value obtained at the time. Figure 1When the throttle opening is 0, the corresponding throttle opening value is 6%. The system uses a throttle opening value of 6% for control. In other words, when the closed-loop speed control of idle condition switches to the speed control process of using throttle to determine throttle opening under rated condition, if the throttle opening value obtained by determining throttle opening under rated condition is less than or greater than the throttle opening value of the idle speed closed loop, then the larger of the two throttle opening values ​​needs to be selected. Otherwise, if the target throttle opening value is calibrated too small, or the throttle output of the idle closed loop is too large, it will cause the engine speed to drop from the idle speed. When the throttle opening obtained by determining throttle opening under rated condition is equal to the throttle opening value of the idle speed closed loop, then the throttle opening value corresponding to the rated condition is directly selected. When the throttle opening corresponding to the rated condition is greater than the throttle opening required by the idle speed closed loop, then the larger of the two throttle opening values ​​still needs to be selected.

[0021] After the load test is completed, the engine needs to be unloaded. After unloading, the engine control unit (ECU) will control the engine speed to decrease from 1500 rpm to 700 rpm under idle conditions. Since the engine uses PID closed-loop control under idle conditions, and the integral value of I is 0, in order to check the deviation between the throttle opening required at the time of switching and the throttle opening under idle conditions, the integral value of I of the idle closed-loop control needs to be reset when the switching state is triggered. The reset value is the throttle opening required under the rated no-load conditions at the time of switching.

[0022] In other words, when the engine speed control using the throttle opening method under rated operating conditions switches to the closed-loop speed control under idle operating conditions, the I-integral value (referring to the I-integral value in the PID controller) of the idle closed-loop control needs to be reset at the moment the switching state is triggered. The reset value is the throttle opening requirement value corresponding to the rated no-load operating conditions at the time of switching. The advantage of this is that if the throttle opening requirement value used for throttle adjustment at the time of switching deviates too much from the throttle opening under idle operating conditions (the throttle opening value of the idle closed-loop is not appropriate, for example, the I-integral output is 0 or very large), it will lead to uneven engine speed control during the switching process. Therefore, this invention reduces the deviation between the throttle opening requirement value used for throttle adjustment at the time of switching and the throttle opening under idle operating conditions by resetting the I-integral value of the idle closed-loop control at the moment the switching state is triggered. The reset value is the throttle opening requirement value corresponding to the rated operating conditions of the previous scheduling cycle, thereby ensuring smooth engine speed control during the switching process.

[0023] The present invention provides a method for adjusting speed by setting a closed-loop output throttle valve at idle speed and a throttle valve opening to switch between the two, thus ensuring that the engine can smoothly switch between idle and rated operating conditions.

[0024] Example 2 This embodiment also provides a speed switching system between engine off-line testing idle speed and rated operating condition, including: The first switching module is configured to, when switching from idle condition to rated condition, if the throttle opening value corresponding to rated condition is less than or greater than the throttle opening value required under rated condition, take the larger value between the two; if the throttle opening value corresponding to rated condition is equal to the throttle opening value required for the idle speed closed loop, take the throttle opening value required directly. The second switching module is configured to reset the I integral value of the idle condition when switching from the rated operating condition to the idle operating condition. The reset value is the throttle opening value required under the rated operating condition at the time of switching.

[0025] The specific implementation methods of the first switching module and the second switching module in the engine speed control switching system between idle and rated operating conditions in this embodiment are described in Embodiment 1 and will not be repeated here.

[0026] Example 3 This embodiment also provides a gas engine off-line testing system, which includes a hydraulic dynamometer, a throttle control knob and an engine control unit; wherein when the engine control unit switches between idle speed and rated speed conditions, the speed switching method between idle speed and rated speed conditions described in Embodiment 1 is used.

[0027] Finally, it should be noted that relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for switching engine speed between idle speed and rated operating condition during off-line testing, characterized in that, as follows: When switching from idle to rated operating condition, if the throttle opening value corresponding to the idle condition is less than or greater than the throttle opening value required under rated operating condition, the larger value between the two shall be taken; if the throttle opening value corresponding to the idle condition is equal to the throttle opening value required under rated operating condition, the throttle opening value required shall be taken directly. When switching from rated operating condition to idle operating condition, the integral value of I in idle operating condition is reset at the moment the switching state is triggered. The reset value is the throttle opening value required under rated no-load operating condition at the time of switching.

2. The method for switching engine speed between idle speed and rated operating condition during off-line testing as described in claim 1, characterized in that, The required throttle opening value under rated operating conditions is obtained by checking the throttle opening when the throttle is turned on.

3. A method for testing an engine after it is decommissioned, comprising an idle speed test and a rated operating condition test, characterized in that, The speed control switching method between idling and rated operating conditions adopts the speed switching method described in claim 1.

4. The engine off-line testing method as described in claim 3, characterized in that, The engine speed control under idling conditions adopts PID control.

5. The engine off-line testing method as described in claim 4, characterized in that, The PID control process is as follows: The engine control unit sends a set speed signal to the engine. At this time, the throttle opens and the engine rotates. The actual speed of the engine is detected in real time. The engine control unit obtains the difference between the actual speed and the set speed, and adjusts the throttle opening in real time through the PID controller to realize PID closed-loop control of the engine under idling conditions.

6. The engine off-line testing method as described in claim 3, characterized in that, The engine speed control under rated operating conditions is achieved by adjusting the throttle position based on the throttle opening.

7. The engine off-line testing method as described in claim 6, characterized in that, The specific method for checking the throttle opening using the accelerator pedal is as follows: The engine control unit sends a rated speed signal to the engine. At this rated speed, different loads are applied to the engine output via a hydraulic dynamometer. The engine speed will decrease at this time. Then, the throttle opening is continuously adjusted so that the engine speed is always maintained at the rated speed.

8. A speed switching system between engine off-line testing idle speed and rated operating condition, characterized in that, include: The first switching module is configured to, when switching from idle condition to rated condition, if the throttle opening value corresponding to the idle condition is less than or greater than the throttle opening value required under rated condition, take the larger value between the two; if the throttle opening value corresponding to the idle condition is equal to the throttle opening value required under rated condition, take the throttle opening value required directly. The second switching module is configured to reset the I integral value of the idle condition when switching from the rated operating condition to the idle operating condition. The reset value is the throttle opening value required under the rated no-load condition at the time of switching.

9. The engine speed switching system between idle speed and rated operating condition during engine off-line testing as described in claim 8, characterized in that, The required throttle opening value under rated operating conditions is obtained by checking the throttle opening when the throttle is turned on.

10. A gas engine factory exit testing system, characterized in that, It includes a hydraulic dynamometer, a throttle control knob, and an engine control unit; when the engine control unit switches between idle and rated operating conditions, it uses the speed control switching method between idle and rated operating conditions as described in claims 1-2.

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