A control method for adaptive identification of gasoline engine pre-ignition
By real-time acquisition and adaptive correction of premature combustion trend parameters, automatically adjusting the air-fuel ratio and torque, suppressing premature combustion of gasoline engines in advance, solving the problem of inability to identify and suppress premature combustion in the existing technology, and improving the stability and driving of the engine sex.
Patent Information
- Application Number
- CN202211095536.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-06
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2042-09-06
AI Technical Summary
The prior art cannot identify and suppress the occurrence of premature combustion of gasoline engines in advance, resulting in unstable combustion state inside the engine, many hot spots distributed, poor suppression effect, and once premature combustion occurs, it may damage the engine.
By collecting ambient temperature, ambient pressure, knock signals and vehicle operating parameters in real time, setting the upper and lower limit preset values of the pre-ignition trend judgment parameters, and calculating the corrected range value through the adaptive correction module to judge the pre-ignition trend and automatically adjust the empty The combustion ratio and torque are used to take pre-ignition measures to prevent premature combustion.
It has achieved early identification of the trend of premature combustion, reduced the probability of premature combustion, and adopted more reasonable inhibitory measures, taking into account premature combustion suppression and vehicle driving, avoiding the damage to the engine by premature combustion.
Smart Images
Figure CN116255263B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of pre-ignition identification and processing, and in particular relates to a control method for self-adaptive identification of pre-ignition of a gasoline engine. Background Art
[0002] At present, the identification and control of pre-ignition is to use a knock sensor to collect combustion vibrations. When an excessively high in-cylinder pressure is identified, it is judged as pre-ignition. After pre-ignition occurs, in order to avoid pre-ignition damaging the engine, the general engine control module will take more radical measures, generally enriching the mixture, adjusting the air-fuel ratio to the minimum value of the adjustable range of 0.7, and at the same time limiting the engine output torque to 70% of the maximum torque. When pre-ignition does not occur again for a period of time, the above parameters are gradually restored to normal values. The above measures will reduce the driving experience and affect user perception, and the existing suppression of pre-ignition is an ex post measure. It cannot well avoid the impact of pre-ignition. Once pre-ignition occurs, the internal combustion state of the engine is extremely unstable, and there are many hot spots, making it difficult to suppress pre-ignition. The suppression effect is poor, and sometimes pre-ignition once is enough to damage the engine. The existing technical solution cannot identify and suppress the occurrence of pre-ignition in advance. Summary of the invention
[0003] The purpose of the present invention is to provide a control method for adaptively identifying pre-ignition of a gasoline engine, aiming to solve the technical problem in the prior art that it is impossible to identify and suppress the occurrence of pre-ignition in advance.
[0004] The present invention is implemented as follows: a control method for adaptively identifying pre-ignition of a gasoline engine, the control method comprising the following steps:
[0005] Step S1: Real-time collection of ambient temperature, ambient pressure, knock signal and vehicle operation parameters, setting vehicle pre-ignition trend judgment parameter upper and lower limit preset values, and correcting the pre-ignition trend judgment parameter upper and lower limit preset values through a preset parameter adaptive correction value calculation module to obtain adaptively corrected pre-ignition trend judgment parameter upper and lower limit range values;
[0006] Step S2: The vehicle operating parameters are compared with the adaptively corrected upper and lower limit range values of the early ignition trend judgment parameters through the parameter comparison module to determine whether they meet the early ignition trend. If it is determined that they meet the early ignition trend, when zero or one group of parameters meet the range value, no action is taken. When two groups of parameters meet, the enriched air-fuel ratio is output as 0.9. When three groups of parameters meet, the enriched air-fuel ratio is output as 0.8 and the shift line is adjusted. When four groups of parameters meet, the enriched air-fuel ratio is output as 0.7 and the shift line is adjusted. If it is determined that there is no early ignition trend, time integration is started. When the time accumulation value is greater than the threshold, the suppression measures taken are restored. When the time accumulation value is less than the threshold, time integration is performed again.
[0007] Step S3: Determine whether the knock signal collected in real time is greater than twice the maximum value of the normal combustion vibration signal. If so, it is determined to be pre-ignition, and the air-fuel ratio is enriched to 0.7, and the torque is limited to 70% of the maximum value. If not, it is determined that the pre-ignition is not identified, and time integration is started. When the accumulated time value is greater than the threshold, the suppression measures taken are restored. When the accumulated time value is less than the threshold, time integration is performed again.
[0008] A further technical solution of the present invention is: in the step S1, the preset upper and lower limit preset values of the pre-ignition trend judgment parameter are corrected by the preset parameter adaptive correction value calculation module, and the upper and lower limit range values of the pre-ignition trend judgment parameter after adaptive correction are calculated by adding the ambient temperature, ambient pressure correction and the value of the parameter record at the time of pre-ignition occurrence.
[0009] A further technical solution of the present invention is: the vehicle operating parameters in step S1 include speed, load, intake air temperature and engine oil temperature.
[0010] A further technical solution of the present invention is: the upper and lower limit preset values of the pre-ignition trend judgment parameters in step S1 include an upper speed preset value, a lower speed preset value, an upper load preset value, a lower load preset value, an upper intake temperature preset value, a lower intake temperature preset value, an upper oil temperature preset value and a lower oil temperature preset value.
[0011] A further technical solution of the present invention is: the upper and lower limit range values of the pre-ignition trend judgment parameter after adaptive correction in the step S1 include upper speed limit correction, lower speed limit correction, upper load limit correction, lower load limit correction, upper intake temperature limit correction, lower intake temperature limit correction, upper oil temperature limit correction and lower oil temperature limit correction.
[0012] A further technical solution of the present invention is: the suppression measures taken for restoring the target air-fuel ratio to 1 and restoring the shift line in step S2 are: restoring the target air-fuel ratio to 1 and restoring the shift line.
[0013] A further technical solution of the present invention is that the suppression measures taken for recovery in step S3 are recovery torque limitation and recovery air-fuel ratio.
[0014] The beneficial effects of the present invention are as follows: this control method predicts the pre-ignition tendency of the engine during the actual driving process of the vehicle through the vehicle operating parameters, so that the ECU can take measures in advance to suppress the pre-ignition, and automatically adjust the parameter threshold of the pre-ignition tendency prediction to adapt to different driving environments and fuels from different countries and regions, identify the pre-ignition tendency in advance, take measures in advance to reduce the probability of pre-ignition, and take more reasonable pre-ignition suppression measures, taking into account both pre-ignition suppression and vehicle drivability. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is a flow chart of a control method for adaptive identification of pre-ignition of a gasoline engine provided by an embodiment of the present invention;
[0016] Figure 2 The present invention provides a flow chart of calculation of a preset parameter adaptive correction value calculation module of a control method for adaptive identification of pre-ignition of a gasoline engine provided by an embodiment of the present invention. DETAILED DESCRIPTION
[0017] Figure 1-2 A control method for adaptive identification of pre-ignition of a gasoline engine provided by the present invention is shown, and the control method comprises the following steps:
[0018] Step S1: Real-time collection of ambient temperature, ambient pressure, knock signal and vehicle operating parameters, setting the upper and lower limit preset values of the vehicle pre-ignition trend judgment parameters, and correcting the upper and lower limit preset values of the pre-ignition trend judgment parameters through the preset parameter adaptive correction value calculation module to obtain the upper and lower limit range values of the pre-ignition trend judgment parameters after adaptive correction.
[0019] Among them, the preset upper and lower limit preset values of the pre-ignition trend judgment parameter are corrected by the preset parameter adaptive correction value calculation module, and the upper and lower limit range values of the pre-ignition trend judgment parameter after adaptive correction are calculated by adding the ambient temperature, ambient pressure correction and the value of the parameter record at the time of pre-ignition occurrence.
[0020] Furthermore, vehicle operating parameters include speed, load, intake air temperature and oil temperature.
[0021] Furthermore, the upper and lower limit preset values of the pre-ignition trend judgment parameters include an upper speed limit preset value, a lower speed limit preset value, an upper load limit preset value, a lower load limit preset value, an intake temperature upper limit preset value, an intake temperature lower limit preset value, an oil temperature upper limit preset value and an oil temperature lower limit preset value.
[0022] Furthermore, the upper and lower limit range values of the pre-ignition trend judgment parameters after adaptive correction include upper speed limit correction, lower speed limit correction, upper load limit correction, lower load limit correction, upper intake temperature limit correction, lower intake temperature limit correction, upper oil temperature limit correction and lower oil temperature limit correction.
[0023] Step S2: The vehicle operating parameters are compared with the upper and lower limit range values of the adaptively corrected pre-ignition trend judgment parameters through the parameter comparison module to determine whether they meet the pre-ignition trend. If it is determined that it meets the pre-ignition trend, when zero or one group of parameters meets the range value, no action is taken. When two groups of parameters meet, the enriched air-fuel ratio is output as 0.9. When three groups of parameters meet, the enriched air-fuel ratio is output as 0.8 and the shift line is adjusted. When four groups of parameters meet, the enriched air-fuel ratio is output as 0.7 and the shift line is adjusted. If it is determined that there is no pre-ignition trend, time integration is started. When the accumulated time value is greater than the threshold, the suppression measures that have been taken are restored. When the accumulated time value is less than the threshold, time integration is performed again. Among them, restoring the suppression measures that have been taken is to restore the target air-fuel ratio to 1 and restore the shift line.
[0024] Step S3: judge the knock signal collected in real time to determine whether it is more than twice the maximum value of the normal combustion vibration signal. If so, it is judged as pre-ignition, and the air-fuel ratio is enriched to 0.7, and the torque is limited to 70% of the maximum value. If not, it is judged that the pre-ignition is not identified, and time integration is started. When the accumulated time value is greater than the threshold, the suppression measures that have been taken are restored. When the accumulated time value is less than the threshold, time integration is performed again; wherein, the suppression measures that have been taken are restored to restore the torque limit and to restore the air-fuel ratio.
[0025] Through the test bench and environmental simulation test chamber, each operating condition of the vehicle engine is tested, and the engine and environmental parameters (such as intake temperature, intake pressure, output torque, engine speed, gear position, oil temperature, ambient temperature, ambient pressure) at the time of pre-ignition and a period of time before the pre-ignition are recorded. The above parameters are statistically calculated to obtain the parameter ranges where pre-ignition is prone to occur. The above ranges are set in the engine control module. When the vehicle operating condition enters the range where pre-ignition is prone to occur, the engine control module recognizes the condition as a mode prone to pre-ignition, and takes measures to suppress pre-ignition in advance.
[0026] The engine control module collects vehicle operating parameters in real time, and the ECU records the operating condition data of the period before the pre-ignition occurs during the actual driving process of the vehicle. The pre-ignition trend prediction parameters are adaptively adjusted to adapt to different driving environments, so that the same pre-ignition calibration data can be used when the vehicle is exported to different countries.
[0027] When the engine control module recognizes that the vehicle is running into a condition prone to pre-ignition, it first takes measures that do not affect the driving experience, such as enriching the mixture and adjusting the automatic transmission shift curve to suppress pre-ignition. When the knock sensor recognizes that pre-ignition has actually occurred, it then takes measures such as limiting torque, adding a richer mixture, and a higher shift curve.
[0028] This control method predicts the pre-ignition trend of the engine during the actual driving process of the vehicle through the vehicle operating parameters, so that the ECU can take measures in advance to suppress pre-ignition and automatically adjust the parameter threshold of the pre-ignition trend prediction to adapt to different driving environments and fuels from different countries and regions. It can identify the pre-ignition trend in advance, take measures in advance, reduce the probability of pre-ignition, and take more reasonable pre-ignition suppression measures, taking into account both pre-ignition suppression and vehicle drivability.
[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A control method for adaptive identification of pre-ignition in a gasoline engine, characterized in that: The control method comprises the following steps: Step S1: Real-time collection of ambient temperature, ambient pressure, knock signal and vehicle operating parameters, setting upper and lower limit preset values of vehicle pre-ignition trend judgment parameters, and correcting the upper and lower limit preset values of pre-ignition trend judgment parameters through a preset parameter adaptive correction value calculation module to obtain adaptively corrected upper and lower limit range values of pre-ignition trend judgment parameters; vehicle operating parameters include speed, load, intake air temperature and engine oil temperature; Step S2: The vehicle operating parameters are compared with the adaptively corrected upper and lower limit range values of the early ignition trend judgment parameters through the parameter comparison module to determine whether they meet the early ignition trend. If it is determined that they meet the early ignition trend, when zero or one group of parameters meet the range value, no action is taken. When two groups of parameters meet, the enriched air-fuel ratio is output as 0.
9. When three groups of parameters meet, the enriched air-fuel ratio is output as 0.8 and the shift line is adjusted. When four groups of parameters meet, the enriched air-fuel ratio is output as 0.7 and the shift line is adjusted. If it is determined that there is no early ignition trend, time integration is started. When the time accumulation value is greater than the threshold, the suppression measures taken are restored. When the time accumulation value is less than the threshold, time integration is performed again. Step S3: Determine whether the knock signal collected in real time is greater than twice the maximum value of the normal combustion vibration signal. If so, it is determined to be pre-ignition, and the air-fuel ratio is enriched to 0.7, and the torque is limited to 70% of the maximum value. If not, it is determined that the pre-ignition is not identified, and time integration is started. When the accumulated time value is greater than the threshold, the suppression measures taken are restored. When the accumulated time value is less than the threshold, time integration is performed again.
2. The control method according to claim 1, characterized in that: In step S1, the preset upper and lower limit preset values of the pre-ignition trend judgment parameter are corrected by the preset parameter adaptive correction value calculation module, and the upper and lower limit range values of the pre-ignition trend judgment parameter after adaptive correction are calculated by adding the ambient temperature, ambient pressure correction and the value of the parameter record at the time of pre-ignition occurrence.
3. The control method according to claim 2, characterized in that: The upper and lower limit preset values of the pre-ignition trend judgment parameters in step S1 include an upper speed preset value, a lower speed preset value, an upper load preset value, a lower load preset value, an upper intake temperature preset value, a lower intake temperature preset value, an upper oil temperature preset value and a lower oil temperature preset value.
4. The control method according to claim 3, characterized in that: The upper and lower limit range values of the pre-ignition trend judgment parameter after adaptive correction in the step S1 include upper speed limit correction, lower speed limit correction, upper load limit correction, lower load limit correction, upper intake temperature limit correction, lower intake temperature limit correction, upper oil temperature limit correction and lower oil temperature limit correction.
5. The control method according to claim 4, characterized in that: The suppression measures taken to restore the target air-fuel ratio to 1 and to restore the shift line in step S2 are as follows.
6. The control method according to claim 5, characterized in that: The suppression measures taken for restoring the torque limit and restoring the air-fuel ratio in step S3 are as follows.