An engine control method, an automobile, and a computer-readable storage medium

Abstract

This invention provides an engine control method, an automobile, and a computer-readable storage medium, relating to the field of automotive technology. The engine control method includes: upon receiving a signal indicating that gasoline has been mistakenly added to the methanol fuel tank, and when the engine has already started in gasoline supply mode, controlling the engine to enter a mixed fuel supply mode. The mixed fuel supply mode includes: detecting the current excess air coefficient of the engine exhaust manifold corresponding to the current air-fuel ratio using an oxygen sensor; maintaining the current air-fuel ratio when the current excess air coefficient is 1; and adjusting the current air-fuel ratio according to the current excess air coefficient when the current excess air coefficient is not 1, until the current excess air coefficient is 1. By continuously adjusting the air-fuel ratio corresponding to the mixed fuel, the final air-fuel ratio can reach the theoretical air-fuel ratio of the mixed fuel, thereby ensuring normal engine operation, avoiding the need to disassemble the methanol fuel tank, and saving energy.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and more specifically, to an engine control method, an automobile, and a computer-readable storage medium. Background Technology

[0002] Methanol, as a clean fuel, can reduce engine carbon emissions, which is beneficial to the environment. However, methanol has a high flash point, and at low temperatures, it cannot directly start an engine, limiting the environmental scope of its application. Currently, in passenger vehicles, methanol is typically used in a gasoline supply mode, where gasoline (with a lower flash point) is used to start the engine, and then switched to a methanol supply mode to maintain the engine's output power and reduce carbon emissions.

[0003] Dual-fuel passenger vehicles typically have two fuel tanks, each with a filler neck for gasoline and methanol, respectively. During vehicle use, it's common for methanol to be mistakenly added to the gasoline tank. When the engine starts and enters methanol supply mode, it's actually burning a mixture of methanol and gasoline. Since gasoline has twice the equivalence of methanol, this results in an excessively rich / lean air-fuel ratio, leading to misfires or engine stalling.

[0004] The current solution is to disassemble the methanol fuel tank, pour out all the mixed fuel, and then treat it as a hazardous chemical. However, this process is time-consuming and labor-intensive, and the gasoline in the mixed fuel is flammable and explosive, posing a significant danger during handling and also resulting in energy waste. Summary of the Invention

[0005] The problem addressed by this invention is how to solve at least one of the aforementioned technical problems.

[0006] To address the aforementioned problems, this invention provides an engine control method that, upon receiving a signal indicating that gasoline has been mistakenly added to the methanol fuel tank, and when the engine has already started in gasoline supply mode, controls the engine to switch to a mixed fuel supply mode. The mixed fuel supply mode includes:

[0007] The oxygen sensor detects the current excess air coefficient in the engine exhaust manifold corresponding to the current air-fuel ratio.

[0008] When the current excess air coefficient is 1, the current air-fuel ratio is maintained;

[0009] When the current excess air coefficient is not 1, the current air-fuel ratio is adjusted according to the current excess air coefficient until the current excess air coefficient is 1.

[0010] The engine control method provided by this invention has, but is not limited to, the following beneficial effects compared to the prior art:

[0011] When gasoline is mistakenly added to the methanol fuel tank, the car owner can send a signal to the control system via a diagnostic tool after the car is powered on. Once the engine has started in gasoline supply mode, the control system will deactivate gasoline supply mode and switch to mixed fuel supply mode. This means the mixed fuel from the methanol fuel tank will be used to supply the engine to maintain its subsequent power output. Specifically, in mixed fuel supply mode, after the fuel and air combust in the engine cylinders, the oxygen sensor at the exhaust manifold detects the excess air coefficient corresponding to the current air-fuel ratio (the mass ratio of air to fuel mixture entering the cylinder). If the excess air coefficient is not 1, it indicates that the current air-fuel ratio is not the stoichiometric air-fuel ratio. The air-fuel ratio is then adjusted, and the excess air coefficient is monitored again until it equals 1. Once the excess air coefficient is 1, the air-fuel ratio is maintained at the level corresponding to an excess air coefficient of 1. By continuously adjusting the air-fuel ratio corresponding to the mixed fuel, the final air-fuel ratio can reach the stoichiometric air-fuel ratio of that mixture, thus ensuring normal engine operation, avoiding the dangers of disassembling the methanol fuel tank, and saving energy.

[0012] Further, adjusting the current air-fuel ratio based on the current excess air coefficient includes:

[0013] The current air-fuel ratio is adjusted using the first formula;

[0014] The first formula is: ;

[0015] in, The adjusted air-fuel ratio, The current air-fuel ratio, This is the current air-fuel ratio correction factor corresponding to the current excess air coefficient.

[0016] Furthermore, the engine control method further includes:

[0017] When the engine is not in closed-loop control mode = ,in, The current excess air coefficient;

[0018] When the engine enters the closed-loop control mode. = ,in, This is the fuel closed-loop correction factor.

[0019] Further, adjusting the current air-fuel ratio based on the current excess air coefficient includes:

[0020] The current air-fuel ratio is adjusted using the second formula;

[0021] The second formula is: ;

[0022] in, This represents the air-fuel ratio after n adjustments. This indicates the air-fuel ratio after n-1 adjustments. This represents the air-fuel ratio correction coefficient after n-1 adjustments, which is the current air-fuel ratio correction coefficient. KFilter is the filter coefficient, which is less than 1.

[0023] Furthermore, the engine control method further includes: gradually decreasing the filter coefficient as the current air-fuel ratio correction coefficient gradually approaches 1;

[0024] As the current air-fuel ratio correction coefficient gradually moves away from 1, the filter coefficient gradually increases.

[0025] Furthermore, when the current air-fuel ratio correction coefficient is in the first interval (0.40, 0.75) or in the second interval (1.25, 1.40), the filter coefficient is set to a first set value;

[0026] When the current air-fuel ratio correction coefficient is in the third interval [0.75, 0.9] or in the fourth interval [1.10, 1.25], the filter coefficient is set to the second set value.

[0027] When the current air-fuel ratio correction coefficient is in the fifth interval (0.9, 1.10), the filter coefficient is set to the third set value;

[0028] Wherein, the first setting value is greater than the second setting value, and the second setting value is greater than the third setting value.

[0029] Furthermore, before the control system enters the mixed fuel supply mode, the engine control method further includes:

[0030] The system controls the engine to operate at medium speed and medium load conditions, controls the electric motor to enter speed control mode to compensate for the engine speed and load, controls the oxygen sensor to activate for a set time, controls the carbon canister flushing function to be turned off, controls the rear oxygen sensor to be turned off, and controls the fuel system diagnostic mode to be turned off.

[0031] Furthermore, the engine control method further includes:

[0032] Once the mixed fuel supply mode is entered, and the level of the mixed fuel in the methanol fuel tank is lower than the set level, the system will exit the mixed fuel supply mode.

[0033] The present invention also provides an automobile, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the engine control method as described above.

[0034] The technological improvements and beneficial effects of the vehicle are at least the same as those of the aforementioned engine control method, therefore, the vehicle will not be described in detail again.

[0035] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the engine control method as described above.

[0036] The technical improvements and beneficial effects of the computer-readable storage medium are at least the same as those of the aforementioned engine control method, therefore, the computer-readable storage medium will not be described in detail again. Attached Figure Description

[0037] Figure 1 This is a schematic flowchart of the engine control method according to an embodiment of the present invention;

[0038] Figure 2 This is a diagram illustrating the effect of gradually adjusting the air-fuel ratio according to an embodiment of the present invention. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0041] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0042] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0043] See Figure 1 An engine control method according to an embodiment of the present invention, when receiving a signal indicating that gasoline has been mistakenly added to the methanol fuel tank, and when the engine has already started in gasoline supply mode, controls the engine to enter a mixed fuel supply mode, wherein the mixed fuel supply mode includes:

[0044] The oxygen sensor detects the current excess air coefficient in the engine exhaust manifold corresponding to the current air-fuel ratio.

[0045] When the current excess air coefficient is 1, the current air-fuel ratio is maintained;

[0046] When the current excess air coefficient is not 1, the current air-fuel ratio is adjusted according to the current excess air coefficient until the current excess air coefficient is 1.

[0047] In this embodiment, when gasoline is mistakenly added to the methanol fuel tank, after the car is powered on, the car owner can send a signal of mistake to the control system via a diagnostic tool. Once the engine has been started in gasoline supply mode, the control system shuts off the gasoline supply mode and enters a mixed fuel supply mode. That is, it supplies the engine with the mixed fuel from the methanol fuel tank to maintain the engine's subsequent output power requirements. Specifically, in mixed fuel supply mode, after the mixed fuel and air burn in the engine cylinder, the oxygen sensor at the exhaust manifold detects the excess air coefficient corresponding to the current air-fuel ratio (the mass ratio of air entering the cylinder to the mixed fuel). If the excess air coefficient is not 1, it indicates that the current air-fuel ratio is not the theoretical air-fuel ratio. In this case, the current air-fuel ratio is adjusted, and the excess air coefficient is continuously detected until it equals 1. After that, the air-fuel ratio is no longer adjusted, and the system maintains the air-fuel ratio corresponding to the excess air coefficient being 1. By continuously adjusting the air-fuel ratio of the mixed fuel, the final air-fuel ratio can reach the theoretical air-fuel ratio of the mixed fuel, thereby ensuring the normal operation of the engine, avoiding the need to disassemble the methanol fuel tank, preventing the dangers of disassembly and assembly, and saving energy.

[0048] The ratio of methanol to gasoline in the methanol fuel tank is uncertain, and it is also uncertain whether there is still methanol in the pipeline between the methanol fuel tank and the methanol pump, or between the methanol pump and the methanol fuel injector. Based on this, after the car is powered on, even if the control system receives a false signal, it can still first enter the gasoline supply mode, that is, start the engine with low flash point gasoline, and then switch to the mixed fuel supply mode after the engine starts.

[0049] As mentioned earlier, because the ratio of methanol to gasoline in the blended fuel in the methanol fuel tank is uncertain, and it is also uncertain whether there is still methanol remaining in the pipeline between the methanol fuel tank and the methanol pump, or in the pipeline between the methanol pump and the methanol injector, the air-fuel ratio can still be set at the theoretical air-fuel ratio corresponding to methanol (the theoretical air-fuel ratio of methanol is 6.5) when the blended fuel supply mode is first entered. Then, the air-fuel ratio is gradually adjusted according to the excess air coefficient to achieve the air-fuel ratio of the blended fuel.

[0050] Optionally, adjusting the current air-fuel ratio based on the current excess air coefficient includes:

[0051] The current air-fuel ratio is adjusted using the first formula;

[0052] The first formula is: ;

[0053] in, The adjusted air-fuel ratio, The current air-fuel ratio, This is the current air-fuel ratio correction factor corresponding to the current excess air coefficient.

[0054] In this embodiment, for example, the original methanol fuel tank contained 10 kg of methanol, and now 5 kg of gasoline has been mistakenly added, forming a 15 kg mixture. The stoichiometric air-fuel ratio of methanol is 6.5, and the stoichiometric air-fuel ratio of gasoline is 14.7. The stoichiometric air-fuel ratio of this mixture should be 9.23. Now, the engine control system needs to adjust the stoichiometric air-fuel ratio of the fuel from that of pure methanol to that of the mixture. Initially, the control system still uses the stoichiometric air-fuel ratio of methanol to proportion the air, that is, 1g of fuel is actually matched with 6.5g of air. After the fuel and air mixture is burned in the engine cylinder, the excess air coefficient detected by the oxygen sensor on the exhaust manifold will be less than 1 (too much fuel, too little air), for example, 0.704. Then, the control system adjusts the current air-fuel ratio according to the first formula to increase the air-fuel ratio, for example, by increasing the amount of air or decreasing the amount of mixed fuel, thereby making the current excess air coefficient approach 1 from 0.704.

[0055] Optionally, the engine control method further includes:

[0056] When the engine is not in closed-loop control mode = ,in, This represents the current excess air coefficient.

[0057] When the engine enters the closed-loop control mode. = ,in, This is the fuel closed-loop correction factor.

[0058] In this embodiment, when the engine is not in closed-loop control mode, the current air-fuel ratio correction coefficient is the reciprocal of the current excess air coefficient. Adjusting the current air-fuel ratio can be achieved by adjusting the air volume. After the engine enters closed-loop control mode, the current air-fuel ratio can be adjusted by adjusting the fuel injection quantity, where the fuel closed-loop correction coefficient can be equal to the current excess air coefficient.

[0059] Optionally, adjusting the current air-fuel ratio based on the current excess air coefficient includes:

[0060] The current air-fuel ratio is adjusted using the second formula;

[0061] The second formula is: ;

[0062] in, This represents the air-fuel ratio after n adjustments. This indicates the air-fuel ratio after n-1 adjustments. KFilter represents the air-fuel ratio correction coefficient when adjusting n-1 times, and KFilter is the filter coefficient, which is less than 1.

[0063] In this embodiment, the air-fuel ratio obtained at the nth adjustment is compared to the air-fuel ratio obtained at the (n-1)th adjustment. The air-fuel ratio obtained at the nth adjustment is the next air-fuel ratio, and the air-fuel ratio obtained at the (n-1)th adjustment is the current air-fuel ratio. n represents the number of times the air-fuel ratio is adjusted. If n=1, it means the air-fuel ratio has been adjusted once. For example, if the original methanol fuel tank contained 10kg of methanol, and now 5kg of gasoline has been mistakenly added, creating a 15kg mixture, the theoretical air-fuel ratio of methanol is 6.5, and the theoretical air-fuel ratio of gasoline is 14.7. Therefore, the theoretical air-fuel ratio of this mixture should be 9.23. The engine control system now needs to adjust the stoichiometric air-fuel ratio from that of pure methanol to that of a mixed fuel. Initially, the control system uses the stoichiometric air-fuel ratio of methanol, meaning 1g of fuel is paired with 6.5g of air. After combustion in the engine cylinders, the excess air coefficient detected by the oxygen sensor on the exhaust manifold will be less than 1 (too much fuel, too little air), for example, 0.704. Then, the control system adjusts the air-fuel ratio according to the second formula. After the first adjustment, the air-fuel ratio increases. Therefore, the air-fuel ratio after the first adjustment = For example, the air-fuel ratio after the first adjustment is 6.8. Then, the air-fuel ratio is adjusted again based on the second air-fuel ratio. Through this iterative adjustment, the current excess air coefficient becomes 1. It can be understood that when the current excess air coefficient is 1, the corresponding current air-fuel ratio has been adjusted to the theoretical air-fuel ratio of the mixed fuel, 9.23. In this embodiment, since a first-order low-pass filter is used when calculating the next air-fuel ratio, the transition to the theoretical air-fuel ratio can be ensured to be smooth and more reliable.

[0064] Optionally, the engine control method further includes: gradually decreasing the filter coefficient as the current air-fuel ratio correction coefficient gradually approaches 1;

[0065] As the current air-fuel ratio correction coefficient gradually moves away from 1, the filter coefficient gradually increases.

[0066] In this embodiment, as can be seen from the aforementioned second formula, the larger the filter coefficient, the greater the adjusted air-fuel ratio; or, the larger the filter coefficient, the greater the difference between the adjusted air-fuel ratio and the current air-fuel ratio. Therefore, in the initial stage, the current air-fuel ratio correction coefficient is usually far from 1, such as the aforementioned 0.704. At this time, the filter coefficient is set to a large value. As the air-fuel ratio gradually approaches the stoichiometric air-fuel ratio, the corresponding excess air coefficient also gradually approaches 1. Then, the filter coefficient is gradually reduced to ensure that the air-fuel ratio can reach the stoichiometric air-fuel ratio quickly and stably. See also... Figure 2 With the gradual adjustment of the air-fuel ratio, from the initial 0.704, as... Figure 2 The gradually adjusting curve shows a stable theoretical air-fuel ratio of 9.23.

[0067] Optionally, when the current air-fuel ratio correction coefficient is in the first interval (0.40, 0.75) or in the second interval (1.25, 1.40), the filter coefficient is set to a first set value.

[0068] When the current air-fuel ratio correction coefficient is in the third interval [0.75, 0.9] or in the fourth interval [1.10, 1.25], the filter coefficient is set to the second set value;

[0069] When the current air-fuel ratio correction coefficient is in the fifth interval (0.9, 1.10), the filter coefficient is set to the third set value;

[0070] Wherein, the first setting value is greater than the second setting value, and the second setting value is greater than the third setting value.

[0071] In this implementation, the filter coefficient can be divided into three values ​​from large to small: a first set value, a second set value, and a third set value. When the current air-fuel ratio correction coefficient is far from 1, that is, when the current excess air coefficient is far from 1, the filter coefficient is set to a larger first set value. For example, when the current air-fuel ratio correction coefficient is in the first interval (0.40, 0.75) or the second interval (1.25, 1.40), the filter coefficient is set to the first set value. When the current air-fuel ratio correction coefficient is not too close to 1, for example, when the current air-fuel ratio correction coefficient is in the third interval [0.75, 0.9] or the fourth interval [1.10, 1.25], the filter coefficient is set to a smaller second set value. When the current air-fuel ratio correction coefficient is close to 1, and the current air-fuel ratio correction coefficient is in the fifth interval (0.9, 1.10), the filter coefficient is set to a very small third set value.

[0072] Optionally, before the control enters the mixed fuel supply mode, the engine control method further includes:

[0073] The system controls the engine to operate at medium speed and medium load conditions, controls the electric motor to enter speed control mode to compensate for the engine speed and load, controls the oxygen sensor to activate for a set time, controls the carbon canister flushing function to be turned off, controls the rear oxygen sensor to be turned off, and controls the fuel system diagnostic mode to be turned off.

[0074] In this embodiment, since the current excess air coefficient needs to be detected by the oxygen sensor (front oxygen sensor) at the exhaust manifold, the following conditions must be met before entering the mixed fuel supply mode to ensure detection accuracy: 1. Control the engine to operate at medium speed and medium load conditions (e.g., speed at 30%-60% of maximum speed, load at 30%-60% of maximum load). If at high or low speeds, even if the air-fuel ratio is accurate and reaches the theoretical air-fuel ratio, incomplete combustion may occur, resulting in the detected current excess air coefficient not being 1. Therefore, it is necessary to control the engine to operate at medium speed and medium load conditions to ensure that the correspondence between the current air-fuel ratio and the current excess air coefficient is accurate. 2. Control the motor to enter speed control mode to compensate for the engine speed and load, avoid engine vibration, and maintain a stable engine speed and load without large fluctuations. 3. The oxygen sensor has been activated for a period of time to ensure that the signal read by the oxygen sensor is stable. 4. Turn off the canister flushing function to suppress the influence of canister flushing on the current excess air coefficient. 5. Turn off the rear oxygen sensor (located after the catalytic converter) to prevent the rear oxygen closed-loop regulation from affecting the current air-fuel ratio adjustment. 6. Disable fuel system diagnostics to ensure the fuel injectors remain operational during air-fuel ratio adjustment. Of course, in case of engine failure, the mixed fuel supply mode can also be forcibly shut off.

[0075] Optionally, the engine control method further includes:

[0076] When the mixed fuel supply mode is entered, and the liquid level of the mixed fuel in the methanol fuel tank is lower than the set liquid level, the control exits the mixed fuel supply mode.

[0077] In this embodiment, if the level of the mixed fuel in the methanol fuel tank is lower than the set level, it means that there is no or almost no mixed fuel left. At this time, the system will exit the mixed fuel supply mode and enter the gasoline supply mode.

[0078] Another embodiment of the present invention provides an automobile, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the engine control method as described above.

[0079] The technological improvements and beneficial effects of the vehicle are at least the same as those of the aforementioned engine control method, therefore, the vehicle will not be described in detail again.

[0080] Another embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the engine control method as described above.

[0081] The technical improvements and beneficial effects of the computer-readable storage medium are at least the same as those of the aforementioned engine control method, therefore, the computer-readable storage medium will not be described in detail again.

[0082] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" and "second" may explicitly or implicitly include at least one of those features.

[0083] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. An engine control method, characterized in that, When a signal indicating that gasoline has been mistakenly added to the methanol fuel tank is received, and the engine has already started in gasoline supply mode, the control switches to mixed fuel supply mode, which includes: The oxygen sensor detects the current excess air coefficient in the engine exhaust manifold corresponding to the current air-fuel ratio. When the current excess air coefficient is 1, the current air-fuel ratio is maintained; When the current excess air coefficient is not 1, the current air-fuel ratio is adjusted according to the current excess air coefficient until the current excess air coefficient is 1. The step of adjusting the current air-fuel ratio based on the current excess air coefficient includes: The current air-fuel ratio is adjusted using the second formula; The second formula is: ； in, This represents the air-fuel ratio after n adjustments. This indicates the air-fuel ratio after n-1 adjustments. K represents the air-fuel ratio correction coefficient when adjusting n-1 times, and KFilter is the filter coefficient, which is less than 1.

2. The engine control method according to claim 1, characterized in that, The engine control method further includes: gradually decreasing the filter coefficient as the current air-fuel ratio correction coefficient gradually approaches 1; As the current air-fuel ratio correction coefficient gradually moves away from 1, the filter coefficient gradually increases.

3. The engine control method according to claim 1, characterized in that, When the current air-fuel ratio correction coefficient is in the first interval (0.40, 0.75) or in the second interval (1.25, 1.40), the filter coefficient is set to the first set value. When the current air-fuel ratio correction coefficient is in the third interval [0.75, 0.9] or in the fourth interval [1.10, 1.25], the filter coefficient is set to the second set value. When the current air-fuel ratio correction coefficient is in the fifth interval (0.9, 1.10), the filter coefficient is set to the third set value; Wherein, the first setting value is greater than the second setting value, and the second setting value is greater than the third setting value.

4. The engine control method according to claim 1, characterized in that, Before the engine control enters the mixed fuel supply mode, the engine control method further includes: The system controls the engine to operate at medium speed and medium load conditions, controls the electric motor to enter speed control mode to compensate for the engine speed and load, controls the oxygen sensor to activate for a set time, controls the carbon canister flushing function to be turned off, controls the rear oxygen sensor to be turned off, and controls the fuel system diagnostic mode to be turned off.

5. The engine control method according to claim 1, characterized in that, The engine control method further includes: Once the mixed fuel supply mode is entered, and the level of the mixed fuel in the methanol fuel tank is lower than the set level, the system will exit the mixed fuel supply mode.

6. A car, characterized in that, The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the engine control method as described in any one of claims 1-5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the engine control method as described in any one of claims 1-5.

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