Control method for transient correction of engine

Abstract

The invention discloses a control method for transient correction of an engine, relates to the field of engine control, and solves the technical problems that the environment is polluted by exhaust gas and the service life of engine oil is influenced by dilution of the engine oil in an existing post-injection transient correction strategy. The method comprises the steps that a transient mode rotating speed difference threshold value, a transient mode rotating speed change rate threshold value and a transient trigger requirement are set, the rotating speed difference and the rotating speed change rate of an engine are obtained, and a first transient trigger condition is set according to the transient mode rotating speed difference threshold value and the rotating speed difference; setting a second transient trigger condition according to the transient mode rotating speed change rate threshold and the rotating speed change rate, judging whether the first transient trigger condition and the second transient trigger condition meet the transient trigger requirement or not, and if yes, entering the transient mode. The transient capacity of the engine is optimized, and white smoke and pollution are reduced.

Description

Technical Field

[0001] This invention relates to the field of engine control, and more specifically, to a control method for engine transient correction. Background Technology

[0002] The transient capability of existing engines is mainly determined by two aspects: performance hardware and transient correction strategies. Common post-injection transient correction strategies primarily maintain the injection point continuously under steady-state conditions, allowing for degraded combustion to increase the exhaust gas energy of the turbocharger. By artificially increasing exhaust energy, the turbocharger can accelerate faster, significantly reducing turbo lag and allowing boost pressure to build up more quickly, further improving the engine's transient load capability. However, existing post-injection transient correction strategies emit visible white smoke (unburned diesel fuel), polluting the environment. Furthermore, prolonged use of post-injection under steady-state conditions may cause some unburned diesel fuel to seep into the engine oil, diluting it, affecting oil life, and further deteriorating the engine's lubrication capabilities. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a control method for engine transient correction in order to address the shortcomings of the prior art, thereby solving the technical problems of exhaust pollution and oil dilution that affect the life of engine oil caused by the existing post-injection transient correction strategy.

[0004] The present invention discloses a control method for transient correction of an engine. The method comprises setting a transient mode speed difference threshold, a transient mode speed change rate threshold, and a transient triggering requirement; acquiring the engine speed difference and speed change rate; setting a first transient triggering condition based on the transient mode speed difference threshold and speed difference; setting a second transient triggering condition based on the transient mode speed change rate threshold and speed change rate; determining whether the first transient triggering condition and the second transient triggering condition meet the transient triggering requirement; if so, entering transient mode.

[0005] As a further improvement, the transient triggering requirement includes a first triggering requirement and a second triggering requirement;

[0006] The first triggering requirement is that the speed difference is greater than the transient mode speed difference threshold; The second triggering requirement is that the rate of change of rotational speed is greater than the threshold for the rate of change of rotational speed in transient mode; First, determine whether the first triggering requirement is met. If so, continue to determine whether the second triggering requirement is met. If the second triggering requirement is still met, then enter the transient mode.

[0007] Furthermore, the first transient triggering condition is whether the speed difference is greater than the transient mode speed difference threshold.

[0008] Furthermore, the second transient trigger condition is whether the rate of change of rotational speed is greater than the transient mode rate of change of rotational speed threshold.

[0009] Furthermore, the transient mode involves setting the target required engine speed, calibrating the rear injection angle and rear injection quantity based on the target required engine speed, and controlling the engine to activate the rear injection based on the rear injection angle and rear injection quantity.

[0010] Furthermore, the transient correction time is calibrated according to the target required rotational speed. When entering the transient mode, the transient correction time starts timing; when the transient correction time ends, the transient mode is exited.

[0011] Furthermore, if the transient triggering requirements are not met, the transient mode will not be entered.

[0012] Beneficial effects The advantages of this invention are: This invention obtains the engine's speed difference and speed change rate by setting transient mode speed difference threshold, transient mode speed change rate threshold, and transient triggering requirements. A first transient triggering condition is set based on the transient mode speed difference threshold and speed difference, and a second transient triggering condition is set based on the transient mode speed change rate threshold and speed change rate. It then determines whether the first and second transient triggering conditions meet the transient triggering requirements; if so, it enters transient mode. No rewiring is required, no corresponding switch is needed, only basic data preparation is required, and the function can be enabled when the software is opened, making it easy to operate. After-injection is only activated when transient mode is entered, thereby optimizing the engine's transient capabilities and reducing white smoke and pollution. Attached Figure Description

[0013] Figure 1 This is a flowchart of the engine transient correction control method of the present invention. Detailed Implementation

[0014] 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.

[0015] See Figure 1 The present invention discloses a control method for transient correction of an engine, wherein the method comprises setting a transient mode speed difference threshold N1, a transient mode speed change rate threshold M1, and a transient triggering requirement, and obtaining the engine speed difference and speed change rate.

[0016] The method for obtaining the engine speed difference is as follows: set the target speed of the engine, obtain the actual speed of the engine, and subtract the target speed from the actual speed to obtain the speed difference N.

[0017] The method for obtaining the engine speed change rate is as follows: set a sampling period, obtain the first average speed in the sampling period, obtain the second average speed in the previous sampling period, and calculate the speed change rate M based on the first average speed and the second average speed.

[0018] The first transient trigger condition is set based on the transient mode speed difference threshold N1 and the speed difference N. The first transient trigger condition is whether the speed difference N is greater than the transient mode speed difference threshold N1.

[0019] A second transient trigger condition is set based on the transient mode speed change rate threshold M1 and the speed change rate M. The second transient trigger condition is whether the speed change rate M is greater than the transient mode speed change rate threshold M1.

[0020] Determine whether the first transient trigger condition and the second transient trigger condition meet the transient trigger requirements. The transient trigger requirements include the first trigger requirement and the second trigger requirement. The first trigger requirement is that the speed difference N is greater than the transient mode speed difference threshold N1, and the second trigger requirement is that the speed change rate M is greater than the transient mode speed change rate threshold M1. First, determine whether the first trigger requirement is met. If it is, then continue to determine whether the second trigger requirement is met. When the second trigger requirement is still met, then enter the transient mode.

[0021] If so, then enter transient mode. If the transient triggering requirements are not met, then do not enter transient mode.

[0022] The transient mode involves setting the target engine speed, calibrating the rear injection angle and fuel quantity based on that speed, and then controlling the engine to activate the rear injection based on these parameters. This ensures that the rear injection only begins when the system enters transient mode, optimizing the engine's transient response and reducing white smoke and pollution.

[0023] The transient correction time is calibrated based on the target required engine speed. Once the transient mode is entered, the transient correction time begins timing; once the transient correction time has elapsed, the transient mode is exited. This means the after-injection is shut off, and the engine continues to operate in its normal PID control mode.

[0024] This function requires no rewiring, has no corresponding switch, only basic data preparation, and can be enabled when the software's internal functions are opened. It is simple to operate and has a low learning curve.

[0025] In practical applications, this transient correction strategy is used in enclosed environments where there are high requirements for the transient load of generator sets and ventilation is not convenient. It is more conducive to the effective operation of the engine, improves the engine's operating environment, reduces smoke emissions from transient loads, and is also a means of optimizing the engine's transient capabilities.

[0026] If the software does not enable the engine transient correction control method function, the engine will use conventional PID control by default to perform transient load increase and decrease stable operation, and the engine will perform transient operations according to the normal normal operation logic.

[0027] Because the engine operates in a complex environment, fixed transient mode speed difference thresholds N1 and M1 cannot meet the varying response requirements of the engine. Therefore, a method for adaptive threshold adjustment is proposed: Since changes in engine load significantly impact the triggering of transient modes—for example, sudden loading and unloading under different loads can instantly alter engine load and intake demand, triggering a transient response—adjusting the transient mode speed difference thresholds N1 and M1 based on the engine's real-time load is feasible. The process involves acquiring the engine's real-time load, calibrating the target load based on the engine's actual speed, subtracting the target load from the real-time load to obtain the load difference, and then calibrating the transient mode speed difference thresholds N1 and M1 based on the actual speed and load difference. This allows for dynamic adjustment of the transient mode speed difference thresholds N1 and M1 based on the engine load and actual engine speed, ultimately meeting different engine response requirements and improving engine stability.

[0028] 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 control method for transient engine correction, characterized in that, The method involves setting a transient mode speed difference threshold, a transient mode speed change rate threshold, and a transient triggering requirement; obtaining the engine speed difference and speed change rate; setting a first transient triggering condition based on the transient mode speed difference threshold and speed difference; setting a second transient triggering condition based on the transient mode speed change rate threshold and speed change rate; and determining whether the first and second transient triggering conditions meet the transient triggering requirement. If so, the system enters transient mode.

2. The control method for transient engine correction according to claim 1, characterized in that, The transient triggering requirements include a first triggering requirement and a second triggering requirement; The first triggering requirement is that the speed difference is greater than the transient mode speed difference threshold; The second triggering requirement is that the rate of change of rotational speed is greater than the threshold for the rate of change of rotational speed in transient mode; First, determine whether the first triggering requirement is met. If so, continue to determine whether the second triggering requirement is met. If the second triggering requirement is still met, then enter the transient mode.

3. The control method for engine transient correction according to claim 1, characterized in that, The first transient trigger condition is whether the speed difference is greater than the transient mode speed difference threshold.

4. The control method for engine transient correction according to claim 1, characterized in that, The second transient trigger condition is whether the rate of change of rotational speed is greater than the threshold for the rate of change of rotational speed in transient mode.

5. The control method for transient engine correction according to claim 1, characterized in that, The transient mode involves setting the target required engine speed, calibrating the rear injection angle and rear injection quantity based on the target required engine speed, and controlling the engine to activate the rear injection based on the rear injection angle and rear injection quantity.

6. The control method for transient engine correction according to claim 1, characterized in that, The transient correction time is calibrated according to the target required speed. When entering the transient mode, the transient correction time starts counting down. When the transient correction time ends, the transient mode is exited.

7. The control method for transient engine correction according to claim 1, characterized in that, If the transient triggering requirements are not met, the transient mode will not be entered.

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