Engine air-fuel ratio adjustment methods, devices, storage media and automobiles

Abstract

This invention provides a method, apparatus, storage medium, and vehicle for adjusting the air-fuel ratio of an engine. The method includes: upon vehicle startup, acquiring a first air-fuel ratio corresponding to the optimal emission level of hydrocarbons; adjusting the current air-fuel ratio to the first air-fuel ratio at a preset rate, and detecting a first-start signal; upon detecting the first-start signal, acquiring a second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides; and adjusting the current air-fuel ratio to the second air-fuel ratio. This invention, by acquiring the first air-fuel ratio corresponding to the optimal emission level of hydrocarbons and the second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides before and after a gear change, flexibly adjusts the air-fuel ratio before and after the vehicle's first start, thereby achieving optimal emissions of various pollutants during cold starts.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more particularly to an engine air-fuel ratio adjustment method, device, storage medium, and automobile. Background Technology

[0002] Existing emission reduction control strategies for improving engine cold starts mainly include increasing cold start idle speed, retarding ignition timing, fuel injection control, and VVT control. However, these existing emission reduction control strategies are generally ineffective. The main reasons for poor emissions during the cold start phase are as follows: low engine coolant temperature and low engine combustion chamber temperature during cold starts result in poor fuel evaporation, atomization, and combustion; the aftertreatment catalyst fails to ignite during cold starts, leading to low catalyst conversion efficiency; and the air-fuel ratio sensor hardware cannot be immediately heated and activated during cold starts, resulting in open-loop air-fuel ratio control that cannot precisely control the air-fuel ratio.

[0003] After selecting key emission components such as the engine, catalyst, and AFS air-fuel ratio sensor, cold start emission control strategies and calibration become crucial for achieving emission standards. However, conventional cold start target air-fuel ratio control strategies are relatively simplistic. To ensure smooth cold start speeds, the air-fuel ratio is first enriched at the bottom of the engine, and then the target air-fuel ratio transitions from the enriched ratio to the stoichiometric ratio. In this scenario, conventional cold start control strategies need to consider both HC / CO and NOx emissions, but they cannot flexibly adjust the target air-fuel ratio based on the emission characteristics of each pollutant to optimize cold start emissions for each pollutant.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide an engine air-fuel ratio adjustment method, device, storage medium, and automobile, aiming to solve the technical problem of the inability to flexibly control the air-fuel ratio during engine cold start in the prior art.

[0006] To achieve the above objectives, the present invention proposes an engine air-fuel ratio adjustment method, the engine air-fuel ratio adjustment method comprising:

[0007] When the vehicle starts, obtain the first air-fuel ratio corresponding to the optimal emission level of hydrocarbons;

[0008] Adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate and detect the vehicle's first start signal;

[0009] Upon detecting the initial start-up signal, the second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides is obtained;

[0010] Adjust the current air-fuel ratio to the second air-fuel ratio.

[0011] Optionally, the step of adjusting the current air-fuel ratio to the second air-fuel ratio includes:

[0012] Determine the delay time for air-fuel ratio adjustment and the enrichment time for the air-fuel ratio;

[0013] Upon detection of the initial start signal, a timer is initiated.

[0014] Accordingly, adjusting the current air-fuel ratio to the second air-fuel ratio includes:

[0015] When the timing duration reaches the delay time, the adjustment of the current air-fuel ratio is initiated, and during the enrichment time, the pre-air-fuel ratio is adjusted to the second air-fuel ratio.

[0016] Optionally, determining the delay time for air-fuel ratio adjustment and the enrichment time of the air-fuel ratio includes:

[0017] Upon detection of the initial start-up signal, the current emissions of nitrogen oxides are obtained;

[0018] The air-fuel ratio adjustment delay time is determined based on the current emissions of nitrogen oxides.

[0019] The air-fuel ratio enrichment time is determined based on the current emissions of nitrogen oxides.

[0020] Optionally, adjusting the current air-fuel ratio to the first air-fuel ratio at a preset rate and detecting the vehicle's first start signal includes:

[0021] Adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate, and detect the vehicle's gear position;

[0022] When the vehicle gear is detected to shift from stationary to sport, the accelerator pedal opening and / or vehicle speed are detected.

[0023] Accordingly, upon detecting the initial start-up signal, obtaining the second air-fuel ratio corresponding to the optimal nitrogen oxide emission level includes:

[0024] When the accelerator pedal opening and / or vehicle speed meet the conditions, obtain the second air-fuel ratio corresponding to the optimal emission of nitrogen oxides.

[0025] Optionally, obtaining the first air-fuel ratio corresponding to the optimal hydrocarbon emissions when the vehicle is started includes:

[0026] When the vehicle is started, the amount of nitrogen oxide emissions during the startup state is collected;

[0027] Within the range where the nitrogen oxide emissions are lower than the preset nitrogen oxide emissions, a first air-fuel ratio corresponding to the optimal hydrocarbon emissions is obtained.

[0028] Optionally, obtaining the second air-fuel ratio corresponding to the optimal nitrogen oxide emission level upon detecting the initial start-up signal includes:

[0029] Upon detection of the initial start-up signal, hydrocarbon emissions during the climb are collected.

[0030] Within the range where hydrocarbon emissions are lower than a preset hydrocarbon emission level, a second air-fuel ratio corresponding to the optimal nitrogen oxide emission level is obtained.

[0031] Optionally, after adjusting the current air-fuel ratio to the second air-fuel ratio, the method further includes:

[0032] Detect current emissions of nitrogen oxides;

[0033] When the current nitrogen oxide emissions reach the target emissions, the current air-fuel ratio is adjusted to the target air-fuel ratio.

[0034] Furthermore, to achieve the above objectives, the present invention also provides an engine air-fuel ratio regulating device, the engine air-fuel ratio regulating device comprising:

[0035] The air-fuel ratio acquisition module is used to acquire the first air-fuel ratio corresponding to the optimal emission of hydrocarbons when the vehicle is started.

[0036] The air-fuel ratio adjustment module is used to adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate and to detect the vehicle's first start signal;

[0037] The air-fuel ratio acquisition module is also used to acquire a second air-fuel ratio corresponding to the optimal emission of nitrogen oxides when the initial start signal is detected.

[0038] The air-fuel ratio adjustment module is also used to adjust the current air-fuel ratio to the second air-fuel ratio.

[0039] In addition, to achieve the above objectives, the present invention also provides a storage medium storing an engine air-fuel ratio adjustment program, wherein when the engine air-fuel ratio adjustment program is executed by a processor, the steps of the engine air-fuel ratio adjustment method are implemented.

[0040] In addition, to achieve the above objectives, the present invention also provides an automobile, the automobile comprising: an engine, a memory, a processor, and an engine air-fuel ratio adjustment program stored in the memory and executable on the processor, wherein when the engine air-fuel ratio adjustment program is executed by the processor, the engine air-fuel ratio adjustment program implements the steps of the engine air-fuel ratio adjustment method as described above.

[0041] This invention provides a method, apparatus, storage medium, and automobile for adjusting the air-fuel ratio of an engine. The method includes: upon vehicle startup, acquiring a first air-fuel ratio corresponding to the optimal emission level of hydrocarbons; adjusting the current air-fuel ratio to the first air-fuel ratio at a preset rate, and detecting the vehicle's first start signal; upon detecting the first start signal, acquiring a second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides; and adjusting the current air-fuel ratio to the second air-fuel ratio. This invention, by acquiring the first air-fuel ratio corresponding to the optimal emission level of hydrocarbons and the second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides before and after a gear change, flexibly adjusts the air-fuel ratio before and after the vehicle's first start, thereby achieving optimal emissions of various pollutants during vehicle cold starts. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the vehicle structure involved in the embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the first process of the first embodiment of the engine air-fuel ratio adjustment method proposed in this invention;

[0045] Figure 3 This is a schematic diagram illustrating the variation of hydrocarbon emissions with vehicle speed in existing technologies.

[0046] Figure 4 This is a schematic diagram illustrating the variation of nitrogen oxide emissions with vehicle speed in existing technologies.

[0047] Figure 5 This is a schematic diagram illustrating the changes in the cold start signal of the air-fuel ratio sensor in existing technology.

[0048] Figure 6 This is a schematic diagram illustrating the changes in the air-fuel ratio signal in existing technologies.

[0049] Figure 7This is a schematic diagram showing the change of hydrocarbon emissions with vehicle speed corresponding to the engine air-fuel ratio adjustment method proposed in this invention.

[0050] Figure 8 This is a schematic diagram illustrating the changes in vehicle gear position during the engine air-fuel ratio adjustment method proposed in this invention.

[0051] Figure 9 This is a schematic diagram showing the change of nitrogen oxide emissions with vehicle speed corresponding to the engine air-fuel ratio adjustment method proposed in this invention.

[0052] Figure 10 This is a theoretical change diagram of the air-fuel ratio under the adjustment method of the engine air-fuel ratio proposed in this invention;

[0053] Figure 11 The actual change diagram of the air-fuel ratio under the adjustment method of the engine air-fuel ratio proposed in this invention;

[0054] Figure 12 The actual change in catalyst bed temperature under the engine air-fuel ratio adjustment method proposed in this invention;

[0055] Figure 13 This is a schematic diagram of the second process of the first embodiment of the engine air-fuel ratio adjustment method proposed in this invention;

[0056] Figure 14 This is a flowchart illustrating the second embodiment of the engine air-fuel ratio adjustment method proposed in this invention;

[0057] Figure 15 This is a schematic diagram of the first process of the third embodiment of the engine air-fuel ratio adjustment method proposed in this invention;

[0058] Figure 16 This is a schematic diagram of the second process of the third embodiment of the engine air-fuel ratio adjustment method proposed in this invention;

[0059] Figure 17 This is a schematic diagram of the engine air-fuel ratio regulating device proposed in this invention.

[0060] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0061] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0063] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0064] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0065] Reference Figure 1 , Figure 1 This is a schematic diagram of the vehicle structure involved in an embodiment of the present invention.

[0066] like Figure 1 As shown, the vehicle may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen, and optionally, it may also include a standard wired interface or a wireless interface. In this invention, the wired interface of the user interface 1003 may be a USB interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wireless-Fi (Wi-Fi) interface). The memory 1005 may be high-speed random access memory (RAM) or non-volatile memory (NVM), such as a disk storage device. The memory 1005 may also optionally be a storage device independent of the aforementioned processor 1001.

[0067] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on the vehicle and may include more or fewer parts than shown, or combine certain parts, or have different arrangements of parts.

[0068] like Figure 1 As shown, the memory 1005, which is identified as a computer storage medium, may include an operating system, a network communication module, a user interface module, and an engine air-fuel ratio adjustment program.

[0069] exist Figure 1 In the vehicle shown, the network interface 1004 is mainly used to connect to the backend server and communicate data with the backend server; the user interface 1003 is mainly used to connect to the user equipment; the vehicle calls the engine air-fuel ratio adjustment program stored in the memory 1005 through the processor 1001 and executes the engine air-fuel ratio adjustment method provided in this embodiment of the invention.

[0070] Reference Figure 2 , Figure 2 This is a schematic diagram of the first process of the first embodiment of the engine air-fuel ratio adjustment method proposed in this invention. Based on the structure of the aforementioned vehicle, the first embodiment of the engine air-fuel ratio adjustment method of this invention is proposed.

[0071] In this embodiment, the engine air-fuel ratio adjustment method includes:

[0072] Step S10: When the vehicle is started, obtain the first air-fuel ratio corresponding to the optimal emission of hydrocarbons.

[0073] It should be understood that, in this embodiment, the executing entity can be a vehicle controller, which can collect information such as the vehicle's operating status, gear status, and vehicle emissions, and then control the hardware in the vehicle based on the collected information to adjust the air-fuel ratio.

[0074] It's easy to understand that during a vehicle's cold start phase, the vehicle's operating states mainly include idling after starting and climbing an incline. The corresponding cold start emissions consist of two parts: emissions during the cold start idling phase and emissions during the initial acceleration and climbing phase after a cold start. The pollutants emitted by the vehicle differ depending on the climbing condition. (Refer to...) Figure 3 During the period after the vehicle starts but before it enters motion, when the vehicle remains at idle (speed is zero), carbon dioxide emissions continuously increase. However, when the vehicle is climbing an incline, carbon dioxide emissions decrease. (Refer to...) Figure 4 Nitrogen oxide emissions are low when the vehicle is idling, but increase rapidly when the vehicle is in motion. (Refer to...) Figure 5 and Figure 6 In the process of controlling the air-fuel ratio during vehicle cold start, the emissions of hydrocarbons and nitrogen oxides are usually taken into account, and the air-fuel ratio is controlled by an emission measurement that meets the requirements of multiple compounds.

[0075] It should be noted that, considering the similar emission characteristics of carbon monoxide and hydrocarbons, in this embodiment, hydrocarbons can be used as representatives of both carbon monoxide and hydrocarbon emissions. That is, hydrocarbons in this application can also be replaced with carbon monoxide emissions. The emissions of hydrocarbons and nitrogen oxides are closely related to the air-fuel ratio. The first air-fuel ratio refers to the air-fuel ratio corresponding to the optimal emission level of hydrocarbons. When the engine operates at the first air-fuel ratio, hydrocarbon emissions are lowest while meeting the requirements for normal vehicle operation.

[0076] In practice, the initial air-fuel ratio can be determined based on hydrocarbon emissions during vehicle cold starts. Since hydrocarbon emissions vary across different vehicle models, the determination of the initial air-fuel ratio should consider the vehicle model and its hydrocarbon emissions. For example, the initial air-fuel ratio corresponding to the lowest emission level can be determined based on the vehicle's hydrocarbon emission curve.

[0077] Step S20: Adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate, and detect the vehicle's first start signal.

[0078] It is understandable that the current air-fuel ratio is the real-time air-fuel ratio during vehicle operation. To ensure smooth cold start speed, the air-fuel ratio is first enriched to a minimum at startup, and then the target air-fuel ratio transitions from the enriched minimum air-fuel ratio to the stoichiometric air-fuel ratio curve. Therefore, this air-fuel ratio is a real-time changing value during the cold start phase. The preset rate is a pre-set rate for adjusting the air-fuel ratio, which is greater than the normal air-fuel ratio adjustment rate. (Refer to...) Figure 7 Adjusting the current air-fuel ratio to the first air-fuel ratio at a preset rate greater than the conventional air-fuel ratio adjustment rate can further reduce hydrocarbon emissions.

[0079] During the initial idling period after vehicle startup, the main compounds emitted are hydrocarbons. To determine the optimal air-fuel ratio for hydrocarbon emissions, the current air-fuel ratio can be adjusted to this ratio at a preset rate, thereby minimizing hydrocarbon emissions during idling. The initial start signal is the signal indicating the first change from a stationary to a moving state after vehicle startup. Of course, during air-fuel ratio adjustment, to prevent changes in vehicle status, the initial start signal needs to be monitored in real time to avoid unbalanced air-fuel ratios and poor emissions after changes in vehicle operating status.

[0080] Step S30: Upon detecting the initial start-up signal, obtain the second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides.

[0081] It should be understood that the initial start signal can be a signal indicating gear shifting. (Refer to...) Figure 8 Upon detecting the initial start signal, the vehicle begins to move. At this point, the composition of the vehicle's emissions changes, shifting from primarily hydrocarbons to nitrogen oxides. The engine's air-fuel ratio needs to be adjusted to determine the optimal second air-fuel ratio for nitrogen oxide emissions.

[0082] The second air-fuel ratio is the air-fuel ratio corresponding to the optimal emission of nitrogen oxides (NOx). Operating under the second air-fuel ratio condition minimizes NOx emissions.

[0083] In practice, the second air-fuel ratio can be determined based on the nitrogen oxide emissions during vehicle cold starts. Similarly, since hydrocarbon emissions vary between different vehicle models, the determination of the second air-fuel ratio can take into account the vehicle model and its hydrocarbon emissions.

[0084] Step S40: Adjust the current air-fuel ratio to the second air-fuel ratio.

[0085] Reference Figure 9 Given that the primary emission from the vehicle is nitrogen oxides, and considering that nitrogen oxides are the main emission factor for nitrogen oxides, the air-fuel ratio can be adjusted to the corresponding second air-fuel ratio when the vehicle switches from idling to climbing mode, thereby reducing nitrogen oxide emissions during cold starts.

[0086] Reference Figure 10 and Figure 11 , Figure 10 This is a theoretical change diagram of the air-fuel ratio under the adjustment method of the engine air-fuel ratio proposed in this invention. Figure 10 During the period from vehicle startup to transition from a stationary to a moving state, the initial air-fuel ratio is higher than the normal air-fuel ratio, and the rate of change of the air-fuel ratio during this time is also significantly greater than the normal rate of change, thus optimizing hydrocarbon emissions. When the vehicle shifts from a stationary to a moving state, the air-fuel ratio suddenly decreases, reaching a second air-fuel ratio within a short time, thereby optimizing nitrogen oxide emissions during the vehicle's climbing phase. Figure 11 The actual change diagram of the air-fuel ratio under the adjustment method of the engine air-fuel ratio proposed in this invention. Figure 11The air-fuel ratio of the engine air-fuel ratio adjustment method of this application differs significantly from conventional air-fuel ratio changes. Under the control method of this application, not only can the emissions of hydrocarbons and carbon monoxide be further improved when the vehicle is idling, but the enrichment of the air-fuel ratio can also be precisely controlled when the vehicle is climbing, thereby maximizing the reduction of nitrogen oxide emissions.

[0087] Furthermore, during the cold start phase of a vehicle, the aftertreatment catalyst fails to ignite, and the ambient temperature is low, meaning the catalyst bed temperature is low, resulting in low catalyst conversion efficiency. However, by using the air-fuel ratio control method of this application, the temperature within the catalyst's environment can be increased, thereby improving the catalyst's catalytic efficiency. (Refer to...) Figure 12 ,exist Figure 12 When the vehicle is climbing a hill, the catalyst temperature rises at a faster rate than under normal air-fuel ratio conditions. Furthermore, the catalyst efficiency is significantly improved when the vehicle is climbing.

[0088] Furthermore, refer to Figure 13 The detection of the vehicle's initial start signal in step S20 includes:

[0089] Step S201: Adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate, and detect the vehicle gear position.

[0090] It should be understood that, in the technical solution of this application, the initial start signal includes at least one of the following: vehicle gear position signal, accelerator pedal opening, and vehicle speed. Typically, changes in the vehicle gear position signal can directly determine whether the vehicle's operating state has changed. When the vehicle gear shifts from a stationary gear to a sport gear, the vehicle begins to move; when the vehicle gear changes between sport gears, the vehicle's state changes according to the gear position signal. The stationary gear is the vehicle's parking gear or idle gear, and the sport gear is the vehicle's forward gear or reverse gear.

[0091] Step S202: When the vehicle gear is detected to switch from stationary gear to sport gear, the accelerator pedal opening and / or vehicle speed are detected.

[0092] Furthermore, the engine's air-fuel ratio is adjusted based on whether the vehicle is idling or climbing, primarily determined by whether the gear position changes. However, in some situations, a gear change does not necessarily indicate a change in the vehicle's state. For example, some drivers habitually shift from stationary to sport gear after starting the vehicle and then use the brakes to keep the vehicle idling. In such cases, adjusting the engine's air-fuel ratio by changing the gear position is not appropriate.

[0093] To more accurately control the engine air-fuel ratio, in this embodiment, the accelerator pedal opening or vehicle speed can be detected when the vehicle shifts from a stationary gear to a sport gear. By combining the vehicle gear with the accelerator pedal opening, or by combining the vehicle gear with the vehicle speed, the vehicle's motion state can be determined more accurately, thereby more accurately controlling the engine air-fuel ratio and reducing emissions of carbon oxides and nitrogen oxides.

[0094] In practice, when the vehicle gear is detected to switch from stationary to sport gear, at least one of the accelerator pedal opening and vehicle speed can be detected to determine whether the vehicle's motion state has changed.

[0095] Accordingly, step S30 includes:

[0096] Step S30': When the accelerator pedal opening and / or vehicle speed meet the conditions, obtain the second air-fuel ratio corresponding to the optimal emission of nitrogen oxides.

[0097] It should be noted that when a change in accelerator pedal opening is detected, the vehicle's motion state can be directly identified as having changed. In this case, the condition for accelerator pedal opening to change is that it has changed. Similarly, when using vehicle speed as a criterion, it can be determined whether the vehicle speed has changed. Typically, at the initial stage of vehicle startup, the vehicle speed is zero. If the vehicle speed changes (is not zero), the vehicle's motion state can also be identified as having changed. To more accurately control the engine's air-fuel ratio, after the vehicle shifts from a stationary gear to a sport gear, a change in vehicle motion state can also be identified when a change in accelerator pedal opening reaches a certain value and / or a change in vehicle speed is detected. In this case, the condition for accelerator pedal opening is that the change in accelerator pedal opening reaches a certain value and / or the vehicle speed reaches a certain value. Once it is determined that the accelerator pedal opening and / or vehicle speed meet the conditions, a second air-fuel ratio can be determined based on the nitrogen oxide emissions during the vehicle's cold start process.

[0098] Reference Figure 14 , Figure 14 This is a flowchart illustrating a second embodiment of the engine air-fuel ratio adjustment method proposed in this invention. Based on the first embodiment described above, a second embodiment of the engine air-fuel ratio adjustment method of this invention is proposed.

[0099] In this embodiment, the method further includes the following step before step S40:

[0100] Step S41: Determine the delay time for air-fuel ratio adjustment and the enrichment time for air-fuel ratio.

[0101] It should be noted that during the process of adjusting the vehicle's current air-fuel ratio to the second air-fuel ratio, at the moment of gear shift, nitrogen oxide emissions have not yet increased significantly, and the adjustment of the engine's air-fuel ratio also requires a certain preparation time. The delay time is the time from the change of gear to the start of the engine's adjustment to the second air-fuel ratio. The preparation time required varies between different vehicle models, therefore the delay time also varies between different vehicle models.

[0102] Enrichment time refers to the time the engine operates at the second air-fuel ratio. Typically, there is a certain time, usually around twenty seconds, between a cold start and normal operation. At the end of the cold start, nitrogen oxide emissions from the vehicle decrease significantly, and the engine can then operate at the target air-fuel ratio (14.6) under normal closed-loop control. The enrichment time is the period during which the engine operates at the second air-fuel ratio until nitrogen oxide emissions are reduced to the level required for normal operation.

[0103] Step S42: Start timing when the first start signal is detected.

[0104] Understandably, given a predetermined delay time for air-fuel ratio adjustment, the initial start signal can be detected. Upon detection of the initial start signal, a timer can be started to begin timing, so that the current air-fuel ratio can be adjusted promptly when the delay time is reached.

[0105] Accordingly, step S40 includes:

[0106] Step S40': When the timing duration reaches the delay time, start adjusting the current air-fuel ratio, and adjust the front air-fuel ratio to the second air-fuel ratio during the enrichment time.

[0107] Understandably, a timer is initiated upon detecting the initial start signal. When the timer reaches its delay, it indicates the vehicle is ready to adjust the current air-fuel ratio, and nitrogen oxide emissions are already at a high level. Therefore, when the timer reaches its delay, the engine's current air-fuel ratio is adjusted to a second air-fuel ratio. This second air-fuel ratio is then maintained until the enrichment time is reached, signifying the vehicle has started and nitrogen oxide emissions have fallen below a certain level.

[0108] Specifically, step S41 includes:

[0109] Step S411: Upon detecting the initial start signal, obtain the current emissions of nitrogen oxides.

[0110] Understandably, upon detecting the initial start-up signal, the engine's nitrogen oxide emissions will continuously increase. When the nitrogen oxide emissions reach a certain threshold, the current air-fuel ratio needs to be adjusted to a second air-fuel ratio. In this embodiment, the current emission level is the real-time nitrogen oxide emission level.

[0111] Step S412: Determine the delay time for air-fuel ratio adjustment based on the current emissions of nitrogen oxides.

[0112] It should be noted that when nitrogen oxide emissions rise to a certain threshold, the engine's current air-fuel ratio needs to be adjusted to a second air-fuel ratio. Upon detecting the initial start-up signal, the delay time for air-fuel ratio adjustment can be determined based on the current nitrogen oxide emissions; specifically, when the current nitrogen oxide emissions are low, the time required to reach the corresponding emission level requiring adjustment is longer, and thus the delay time is also longer. Considering that the current emissions at the time of gear shift may differ for different vehicle models, in this embodiment, the current nitrogen oxide emissions can also be determined based on the vehicle model.

[0113] Step S413: Determine the enrichment time of the air-fuel ratio based on the current emissions of nitrogen oxides.

[0114] It should be noted that, given the current emissions, the delay time for air-fuel ratio adjustment can be determined first. After adjusting the air-fuel ratio, the engine will maintain the second air-fuel ratio, directly reducing nitrogen oxide emissions to meet the standards for normal vehicle operation. In this case, the emissions at the moment of air-fuel ratio adjustment can be determined based on the current emissions, and then the time required for the emissions to reach the normal operating state of the vehicle, i.e., the enrichment time of the air-fuel ratio, can be determined based on the emissions at the moment of air-fuel ratio adjustment.

[0115] Furthermore, considering that the enrichment time is also related to the initial enrichment percentage, which is the ratio of the change in air-fuel ratio concentration at the moment of start-up, the F / H calibration scheme can be used to determine the enrichment time and the initial enrichment percentage. This scheme can determine the enrichment time and the initial enrichment percentage by analyzing the measured air-fuel ratios corresponding to each enrichment time and initial enrichment percentage at 20°C or 30°C, as well as the nitrogen oxides collected per second under different air-fuel ratio conditions during the air-fuel ratio test. Using these data, the enrichment time and initial enrichment percentage can be determined, and the engine air-fuel ratio can be adjusted when the vehicle switches from a stationary state to a moving state.

[0116] In this embodiment, by determining the delay time for adjusting the air-fuel ratio of the engine and the enrichment time of the air-fuel ratio, the air-fuel ratio of the engine can be controlled more accurately.

[0117] Based on the first or second embodiment described above, a third embodiment of the engine air-fuel ratio adjustment method of the present invention is proposed.

[0118] Reference Figure 15 In this embodiment, step S10 includes:

[0119] Step S101: When the vehicle is started, collect the nitrogen oxide emissions in the start-up state.

[0120] It should be noted that nitrogen oxide emissions vary with the air-fuel ratio. Therefore, when adjusting the air-fuel ratio to control hydrocarbon emissions, nitrogen oxide emissions also need to be monitored to avoid a sharp deterioration in nitrogen oxide emissions during the adjustment from the current air-fuel ratio to the first air-fuel ratio. In such a case, although hydrocarbon emissions can be reduced, the resulting increase in nitrogen oxide emissions is clearly not worthwhile. Therefore, in this embodiment, nitrogen oxide emissions can also be collected when the vehicle starts.

[0121] Step S102: Within the range where the nitrogen oxide emissions are lower than the preset nitrogen oxide emissions, obtain the first air-fuel ratio corresponding to the optimal hydrocarbon emissions.

[0122] It should be noted that the preset nitrogen oxide emission levels are predetermined values ​​designed to meet the normal nitrogen oxide emission requirements. Within the preset nitrogen oxide emission levels, hydrocarbon emissions have not deteriorated drastically.

[0123] It is understandable that the preset nitrogen oxide emission level can be a standard value or a range value. Since nitrogen oxide emissions are related to the air-fuel ratio, when nitrogen oxide emissions are within the preset nitrogen oxide emission level range, the air-fuel ratio also corresponds to a range. At this time, the air-fuel ratio corresponding to the lowest hydrocarbon emission value within the range of the air-fuel ratio can be selected as the first air-fuel ratio.

[0124] Furthermore, in this embodiment, step S30 further includes:

[0125] Step S301: When the initial start signal is detected, collect the hydrocarbon emissions during the climb.

[0126] Understandably, controlling the air-fuel ratio based on hydrocarbon emissions requires considering nitrogen oxide (NOx) emissions to prevent NOx emissions from worsening during air-fuel ratio adjustment. Similarly, adjusting the air-fuel ratio based on NOx emissions also requires considering hydrocarbon emissions to avoid this worsening. Therefore, upon detecting the initial start-up signal, hydrocarbon emissions must be monitored to ensure the selected air-fuel ratio does not lead to increased hydrocarbon emissions.

[0127] Step S302: Within the range where the hydrocarbon emissions are lower than the preset hydrocarbon emissions, obtain the second air-fuel ratio corresponding to the optimal nitrogen oxide emissions.

[0128] It should be noted that the preset hydrocarbon emission levels are predetermined to meet the conventional hydrocarbon emission requirements. Within the preset hydrocarbon emission levels, nitrogen oxide emissions have not deteriorated drastically.

[0129] It is understandable that the preset hydrocarbon emission level can be a standard value or a range value. Since hydrocarbon emissions are related to the air-fuel ratio, when hydrocarbon emissions are within the preset hydrocarbon emission level, the air-fuel ratio also corresponds to a range. In this case, the air-fuel ratio corresponding to the lowest nitrogen oxide emission level within the range of the air-fuel ratio can be selected as the second air-fuel ratio.

[0130] Furthermore, refer to Figure 16 Following step 40, the following is included:

[0131] Step 50: Detect the current emissions of nitrogen oxides.

[0132] It should be understood that during the air-fuel ratio adjustment process of a vehicle engine, the emission of nitrogen oxides (NOx) gradually decreases until it reaches a stable value. When the NOx emission reaches this stable value, it indicates that the cold start of the vehicle has been completed. At this point, the engine air-fuel ratio can be adjusted to the target air-fuel ratio for normal engine operation. This target air-fuel ratio is a closed-loop control target air-fuel ratio, typically 14.6.

[0133] Therefore, in this embodiment, the current emission of nitrogen oxides also needs to be monitored in real time during the air-fuel ratio adjustment process.

[0134] Step 60: When the current emission level of nitrogen oxides reaches the target emission level, adjust the current air-fuel ratio to the target air-fuel ratio.

[0135] It is understandable that the target emission level is the amount of nitrogen oxides emitted by the vehicle after a cold start. When the current nitrogen oxide emission level reaches the target emission level, it indicates that the vehicle has completed a cold start, and the engine's current air-fuel ratio can be adjusted to the target air-fuel ratio.

[0136] Furthermore, since the enrichment time of the engine's air-fuel ratio is related to the emission of nitrogen oxides, in this embodiment, the duration of the recorded second air-fuel ratio can be used as a benchmark to determine whether the vehicle has completed a cold start. If the duration of the second air-fuel ratio reaches the enrichment time, the current air-fuel ratio can be adjusted to the target air-fuel ratio to complete the vehicle's cold start.

[0137] In addition, to achieve the above objectives, the present invention also provides a storage medium storing an engine air-fuel ratio adjustment program, wherein when the engine air-fuel ratio adjustment program is executed by a processor, the steps of the engine air-fuel ratio adjustment method are implemented.

[0138] In addition, refer to Figure 17 To achieve the above objectives, the present invention also provides an engine air-fuel ratio regulating device, the engine air-fuel ratio regulating device comprising:

[0139] The air-fuel ratio acquisition module 10 is used to acquire the first air-fuel ratio corresponding to the optimal emission of hydrocarbons when the vehicle is started.

[0140] The air-fuel ratio adjustment module 20 is used to adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate and detect the vehicle's first start signal;

[0141] The air-fuel ratio acquisition module 10 is also used to acquire a second air-fuel ratio corresponding to the optimal emission of nitrogen oxides when the first start signal is detected.

[0142] The air-fuel ratio adjustment module 20 is also used to adjust the current air-fuel ratio to the second air-fuel ratio.

[0143] This application uses an air-fuel ratio acquisition module 10 to acquire a first air-fuel ratio corresponding to the optimal emission level of hydrocarbons when the vehicle starts; an air-fuel ratio adjustment module 20 adjusts the current air-fuel ratio to the first air-fuel ratio at a preset rate and detects the vehicle's first start signal; when the first start signal is detected, the air-fuel ratio acquisition module 10 acquires a second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides; and the air-fuel ratio adjustment module 20 adjusts the current air-fuel ratio to the second air-fuel ratio. This application acquires the first air-fuel ratio corresponding to the optimal emission level of hydrocarbons and the second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides before and after a gear shift, flexibly adjusting the air-fuel ratio before and after gear changes to achieve optimal emissions of various pollutants during vehicle cold starts.

[0144] In addition, in this application, the engine air-fuel ratio regulating device can also flexibly adjust the air-fuel ratio in other ways. For specific methods, please refer to the above-described engine air-fuel ratio regulating method embodiments, which will not be elaborated here.

[0145] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for adjusting the air-fuel ratio of an engine, characterized in that, The engine air-fuel ratio adjustment method includes: When the vehicle starts, obtain the first air-fuel ratio corresponding to the optimal emission level of hydrocarbons; Adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate and detect the vehicle's first start signal; Upon detecting the initial start-up signal, the second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides is obtained; Adjust the current air-fuel ratio to the second air-fuel ratio; The step of obtaining the first air-fuel ratio corresponding to the optimal hydrocarbon emissions when the vehicle is started includes: When the vehicle is started, the amount of nitrogen oxide emissions during the startup state is collected; Within the range where the nitrogen oxide emissions are lower than the preset nitrogen oxide emissions, a first air-fuel ratio corresponding to the optimal hydrocarbon emissions is obtained; The step of obtaining the second air-fuel ratio corresponding to the optimal emission level of nitrogen oxides upon detecting the initial start-up signal includes: Upon detection of the initial start-up signal, hydrocarbon emissions during the climb are collected. Within the range where hydrocarbon emissions are lower than a preset hydrocarbon emission level, a second air-fuel ratio corresponding to the optimal nitrogen oxide emission level is obtained.

2. The engine air-fuel ratio adjustment method as described in claim 1, characterized in that, Before adjusting the current air-fuel ratio to the second air-fuel ratio, the following steps are included: Determine the delay time for air-fuel ratio adjustment and the enrichment time for the air-fuel ratio; Upon detection of the initial start signal, a timer is initiated. Accordingly, adjusting the current air-fuel ratio to the second air-fuel ratio includes: When the timing duration reaches the delay time, the adjustment of the current air-fuel ratio is initiated, and during the enrichment time, the pre-air-fuel ratio is adjusted to the second air-fuel ratio.

3. The engine air-fuel ratio adjustment method as described in claim 2, characterized in that, The determination of the delay time for air-fuel ratio adjustment and the enrichment time of the air-fuel ratio includes: Upon detection of the initial start-up signal, the current emissions of nitrogen oxides are obtained; The air-fuel ratio adjustment delay time is determined based on the current emissions of nitrogen oxides. The air-fuel ratio enrichment time is determined based on the current emissions of nitrogen oxides.

4. The engine air-fuel ratio adjustment method as described in claim 1, characterized in that, The step of adjusting the current air-fuel ratio to the first air-fuel ratio at a preset rate and detecting the vehicle's first start signal includes: Adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate, and detect the vehicle's gear position; When the vehicle gear is detected to shift from stationary to sport, the accelerator pedal opening and / or vehicle speed are detected. Accordingly, upon detecting the initial start-up signal, obtaining the second air-fuel ratio corresponding to the optimal nitrogen oxide emission level includes: When the accelerator pedal opening and / or vehicle speed meet the conditions, obtain the second air-fuel ratio corresponding to the optimal emission of nitrogen oxides.

5. The engine air-fuel ratio adjustment method according to any one of claims 1-4, characterized in that, After adjusting the current air-fuel ratio to the second air-fuel ratio, the method further includes: Detect current emissions of nitrogen oxides; When the current nitrogen oxide emissions reach the target emissions, the current air-fuel ratio is adjusted to the target air-fuel ratio.

6. An engine air-fuel ratio regulating device, characterized in that, The engine air-fuel ratio regulating device includes: The air-fuel ratio acquisition module is used to acquire the first air-fuel ratio corresponding to the optimal emission of hydrocarbons when the vehicle is started. The air-fuel ratio adjustment module is used to adjust the current air-fuel ratio to the first air-fuel ratio at a preset rate and to detect the vehicle's first start signal; The air-fuel ratio acquisition module is also used to acquire a second air-fuel ratio corresponding to the optimal emission of nitrogen oxides when the initial start signal is detected. The air-fuel ratio adjustment module is further configured to adjust the current air-fuel ratio to the second air-fuel ratio; The air-fuel ratio acquisition module is also used to collect the nitrogen oxide emissions during vehicle startup; and to obtain the first air-fuel ratio corresponding to the optimal hydrocarbon emissions within the range where the nitrogen oxide emissions are lower than the preset nitrogen oxide emissions. The air-fuel ratio acquisition module is also used to collect hydrocarbon emissions during the climb when the initial start signal is detected; and to acquire a second air-fuel ratio corresponding to the optimal nitrogen oxide emissions within the range where the hydrocarbon emissions are lower than the preset hydrocarbon emissions.

7. A storage medium, characterized in that, The storage medium stores an engine air-fuel ratio adjustment program, which, when executed by a processor, implements the steps of the engine air-fuel ratio adjustment method as described in any one of claims 1 to 5.

8. A car, characterized in that, The vehicle includes: an engine, a memory, a processor, and an engine air-fuel ratio adjustment program stored in the memory and executable on the processor, wherein when the engine air-fuel ratio adjustment program is executed by the processor, it implements the steps of the engine air-fuel ratio adjustment method as described in any one of claims 1 to 5.

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