Fuel component identification method for flexible fuel engine, storage medium, and vehicle

Abstract

The application provides a flexible fuel engine fuel component identification method, a storage medium and a vehicle, and relates to the technical field of engines.The method comprises the following steps: after detecting that refueling operation of a vehicle occurs, the refueling volume is acquired, the maximum estimated content of a first fuel in a flexible fuel tank after refueling is generated according to the refueling volume; the flexible fuel tank is controlled to inject fuel according to the maximum estimated content of the first fuel, and the actual air-fuel ratio in the engine is acquired after a preset injection time length; a theoretical air-fuel ratio is acquired; the actual air-fuel ratio is compared with the theoretical air-fuel ratio, and the actual content of the first fuel in the flexible fuel tank after refueling is determined based on the comparison result.The application can realize rapid acquisition of fuel components without relying on a fuel sensor, reduce development cost, improve self-learning speed, improve combustion stability and avoid engine stall.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engines, in particular to a fuel component identification method of a flexible fuel engine, a storage medium and a vehicle. BACKGROUND

[0002] The flexible fuel engine refers to an engine capable of using pure gasoline fuel, pure alcohol fuel and mixed fuel of gasoline and alcohol fuel in different proportions. After refueling the corresponding mixed fuel tank of the flexible fuel engine, the fuel component in the tank will change suddenly, and the air-fuel ratio may also change suddenly. For example, for a methanol / gasoline flexible fuel, since the equivalent ratio of methanol and gasoline is quite different, if gasoline is injected into the tank originally containing methanol, the air-fuel ratio of the mixed fuel will change suddenly. The sudden change of the air-fuel ratio of the fuel may cause the ECU (Engine control unit: engine controller) oil circuit self-learning deviation to be too large, and then related oil circuit faults are reported, and in severe cases, it may cause the engine to stall.

[0003] At present, the fuel sensor is mainly used to detect the fuel component in the tank. However, the cost of using the fuel sensor is high. SUMMARY

[0004] The problem solved by the present application is how to reduce the cost of identifying the fuel component in the tank.

[0005] To solve the above problems, the present application provides a fuel component identification method of a flexible fuel engine, comprising:

[0006] After detecting that the vehicle is refueled, the refueling volume is obtained, and the maximum estimated content of the first fuel in the flexible fuel tank after refueling is generated according to the refueling volume;

[0007] The flexible fuel tank is controlled to inject oil according to the maximum estimated content of the first fuel, and the actual air-fuel ratio in the engine is obtained after a preset injection time;

[0008] The theoretical air-fuel ratio is obtained, wherein the theoretical air-fuel ratio is the air-fuel ratio calculated by injecting oil according to the first fuel when the actual refueling fuel is the second fuel, or the air-fuel ratio calculated by injecting oil according to the first fuel when the actual refueling fuel is the first fuel;

[0009] The actual air-fuel ratio is compared with the theoretical air-fuel ratio, and the actual content of the first fuel in the flexible fuel tank after refueling is determined based on the comparison result.

[0010] Optionally, the theoretical air-fuel ratio is an air-fuel ratio calculated according to the first fuel when the actual refueling fuel is the first fuel; and the determining the actual content of the first fuel in the flexible tank after refueling based on the comparison result comprises:

[0011] when the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within a preset threshold range, determining that the actual content of the first fuel is a minimum estimated content of the first fuel in the flexible tank after refueling generated based on the refueling volume;

[0012] when the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is outside the preset threshold range, determining that the actual content of the first fuel is a maximum estimated content of the first fuel.

[0013] Optionally, the theoretical air-fuel ratio is an air-fuel ratio calculated according to the first fuel when the actual refueling fuel is the first fuel; and the determining the actual content of the first fuel in the flexible tank after refueling based on the comparison result comprises:

[0014] when the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within a preset threshold range, determining that the actual content of the first fuel is a maximum estimated content of the first fuel;

[0015] when the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is outside the preset threshold range, determining that the actual content of the first fuel is a minimum estimated content of the first fuel in the flexible tank after refueling generated based on the refueling volume.

[0016] Optionally, after the controlling the flexible tank to inject fuel according to the maximum estimated content of the first fuel, the method further comprises:

[0017] controlling at least one tank other than the flexible tank to inject fuel.

[0018] Optionally, after the controlling the flexible tank to inject fuel according to the maximum estimated content of the first fuel, the method further comprises:

[0019] calculating a cumulative injection volume of the flexible tank after refueling;

[0020] when the cumulative injection volume is greater than a preset volume, controlling at least one tank other than the flexible tank to inject fuel.

[0021] Optionally, the preset volume is a sum of a volume of a fuel pipe and a volume of a fuel rail.

[0022] Optionally, the generating the maximum estimated content of the first fuel in the flexible tank after refueling according to the refueling volume comprises:

[0023] According to the density of the first fuel and the refueling volume, a new mass of the first fuel is calculated;

[0024] A total mass of residual fuel in the flexible fuel tank before refueling and a residual mass of the first fuel are obtained;

[0025] Based on the new mass, the total mass and the residual mass, a maximum estimated content of the first fuel is generated.

[0026] Optionally, the obtaining of the theoretical air-fuel ratio comprises:

[0027] A first equivalent ratio of fuel in the flexible fuel tank after refueling is determined according to the first fuel as the refueling fuel;

[0028] An in-cylinder intake air amount is obtained, and a consumed air amount of the flexible fuel tank is determined according to the in-cylinder intake air amount;

[0029] A target air-fuel ratio is obtained, and an injection amount corresponding to the first fuel is generated according to the consumed air amount of the flexible fuel tank, the first equivalent ratio and the target air-fuel ratio;

[0030] A second equivalent ratio of fuel in the flexible fuel tank after refueling is determined according to the second fuel as the refueling fuel;

[0031] An injection fuel mass is determined according to the injection amount corresponding to the first fuel and the second equivalent ratio;

[0032] The theoretical air-fuel ratio is generated according to a fuel mass required for consuming the in-cylinder intake air amount and the injection fuel mass.

[0033] To solve the above problems, the application further provides a computer readable storage medium, which stores a computer program, and the computer program is read and run by a processor to realize the fuel component identification method of the flexible fuel engine.

[0034] To solve the above problems, the application further provides a vehicle, which comprises a computer readable storage medium storing a computer program and a processor, and the computer program is read and run by the processor to realize the fuel component identification method of the flexible fuel engine.

[0035] Compared with the prior art, the application has at least the following technical effects:

[0036] By predicting the possible fuel ratio after refueling according to the refueling volume in advance after detecting that the vehicle is refueled, and performing tentative fuel injection control according to the possible fuel ratio, the actual air-fuel ratio caused by the tentative fuel injection control is obtained, which is compared with the theoretical air-fuel ratio, and the actual content of the first fuel in the flexible fuel tank after refueling is determined based on the comparison result, so that the rapid acquisition of the fuel component without relying on the fuel sensor is realized, and then the ECU oil circuit self-learning deviation is limited within a reasonable range, which not only can improve the self-learning speed and improve the combustion stability, avoid misfire, but also can reduce the development cost. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 A flowchart of a fuel component identification method of a flexible fuel engine according to an embodiment of the present application is shown in the figure.

[0038] Figure 2 A fuel distribution diagram of a methanol / gasoline flexible fuel vehicle according to an embodiment of the present application is shown in the figure.

[0039] Figure 3 Another flowchart of a fuel component identification method of a flexible fuel engine according to an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes, and are not intended to limit the protection scope of the present application.

[0041] Compared with a single fuel engine, the biggest challenge of the engine electronic control system of a flexible fuel engine is to obtain the fuel equivalence ratio. In the engine refueling scenario, adding new fuel will cause the fuel component in the tank to change, and the fuel equivalence ratio in the tank may change suddenly. For example, the methanol equivalence ratio (6.45) is only about 43% of the gasoline equivalence ratio (14.7), and if gasoline is added to the methanol tank, the equivalence ratio of the mixed fuel will change suddenly. In this regard, although the fuel component can be learned through the oxygen sensor without any strategy, due to the large equivalence ratio deviation of the mixed fuel before and after refueling, it takes a long time to calculate the fuel component from the feedback signal of the oxygen sensor, and the learning speed is too slow, which may cause unstable combustion and even misfire. However, although the fuel sensor can quickly identify the fuel component, the cost is high.

[0042] Based on the above background, the present application provides a fuel component identification method for a flexible fuel engine, a storage medium and a vehicle.

[0043] The air-fuel ratio herein refers to the mass ratio between air and fuel in the mixture. The equivalence ratio refers to the amount of air required for complete combustion of unit mass of fuel in theory.

[0044] As Figure 1 In the embodiment of the present application, the fuel component identification method of the flexible fuel engine comprises:

[0045] Step S100, after detecting that the vehicle is refueled, the refueling volume is obtained, and the maximum estimated content of the first fuel in the refueled flexible fuel tank is generated according to the refueling volume.

[0046] The refueling operation can be determined by judging whether the change of the tank level is greater than a certain threshold. The refueling operation can also be determined by comprehensively judging the change of the tank level and the state of the tank cap. Specifically, whether the tank cap is opened is determined by the state of the tank cap, and whether the tank level rises is determined by the tank level. If the tank cap is opened and the tank level rises, it is determined that the engine is refueled. By comprehensively judging the change of the tank level and the state of the tank cap, it can be avoided that the change of the tank level caused by vehicle shaking and tank sloshing is misjudged as refueling, and it can also be avoided that the scene of opening the tank cap for other purposes such as tank inspection is identified as a refueling scene, thereby improving the accuracy of the refueling operation judgment and avoiding the mis-triggering of the program corresponding to the fuel component identification method of the flexible fuel engine in the embodiment of the present application, and improving the stability of the engine and the overall vehicle system. The refueling flag can be set to identify the refueling state after comprehensively judging whether the refueling operation occurs by the change of the tank level and the state of the tank cap. When the refueling flag changes to refueled, the rapid fuel self-learning strategy is triggered, and the program corresponding to the fuel component identification method of the flexible fuel engine in the embodiment of the present application is executed. After the fuel component identification method of the flexible fuel engine in the embodiment of the present application is executed, the refueling flag changes to unrefueled state.

[0047] After the fuel component identification method of the flexible fuel engine in the embodiment of the present application is started to be executed, operations such as carbon can flushing and catalyst heating are prohibited to avoid affecting the learning of air-fuel ratio.

[0048] Further, the refueling volume can be determined by the change of the liquid level before and after refueling. Specifically, the total volume of fuel after refueling is obtained by a sensor, the remaining fuel volume before refueling is obtained, the difference between the total volume of fuel and the remaining fuel volume is calculated to obtain the refueling volume, and the remaining fuel volume before refueling can be stored by collecting before each shutdown.

[0049] After the refueling volume is determined, the maximum estimated content of the first fuel after refueling is generated based on the refueling volume. The first fuel refers to one of the mixed fuels. For methanol / gasoline flexible fuel, the first fuel refers to one of methanol and gasoline. For ethanol / gasoline flexible fuel, the first fuel refers to one of ethanol and gasoline, and the specific fuel type of the first fuel is set according to user demand.

[0050] The estimated content refers to the estimated content ratio of the first fuel in the flexible fuel tank (also referred to as the mixed fuel tank) after refueling, such as the estimated mass ratio or the estimated volume ratio.

[0051] Because the available fuel type of the flexible fuel engine is determined, such as for a methanol / gasoline flexible fuel engine, the refueled fuel must be one of methanol and gasoline, i.e. there are only two cases for the refueled fuel type, based on which, in combination with the refueling volume, the estimated content of the first fuel in the two cases can be estimated. By identifying the newly refueled fuel as the first fuel, the maximum estimated content of the first fuel can be generated, and by identifying the newly refueled fuel as the second fuel, the minimum estimated content of the first fuel can be generated. The maximum and minimum estimated contents of the first fuel can be determined by the refueling volume, the density of the first fuel, and the remaining fuel volume before refueling.

[0052] In an embodiment, for a methanol / gasoline flexible fuel engine, the first fuel is methanol and the second fuel is gasoline, after detecting that the vehicle has been refueled, the refueling volume is obtained, and the maximum mass ratio of methanol in the flexible fuel tank after refueling is generated according to the refueling volume.

[0053] In step S200, the flexible fuel tank is controlled to spray fuel according to the maximum estimated content of the first fuel, and after a preset time length of fuel injection, the actual air-fuel ratio in the engine is obtained.

[0054] The injection amount of the injector corresponding to the flexible fuel tank is controlled according to the maximum estimated content of the first fuel. In an embodiment, the injection amount of the injector corresponding to the flexible fuel tank is controlled according to the maximum mass ratio of methanol, and fuel injection control is performed.

[0055] The air-fuel ratio is used to measure the concentration of the mixture of air and fuel in the engine. When the air-fuel ratio is equal to or close to 1, the concentration of the mixture is close to the theoretical mixture ratio. When the air-fuel ratio is greater than 1, the mixture is lean. When the air-fuel ratio is less than 1, the mixture is rich.

[0056] Optionally, the ratio of the air-fuel ratio to the equivalence ratio is taken as the air-fuel ratio.

[0057] Optionally, the ratio of the fuel mass required by the air in the cylinder of the complete combustion engine to the total mass of the fuel actually injected by the tank is taken as the air-fuel ratio.

[0058] Because there is a pure physical delay in the pipeline and a response delay of the oxygen sensor itself from the execution of fuel injection by the injector to the detection of the signal corresponding to the combustion of this injection by the oxygen sensor to generate the air-fuel ratio, after a preset time length of fuel injection, the actual air-fuel ratio in the engine is obtained again to obtain a more accurate air-fuel ratio, which more accurately reflects the actual state of the current injection. The preset time length can be determined by the user according to the actual pipeline conditions of the engine and the performance of the oxygen sensor.

[0059] In one embodiment, after the flexible tank sprays the first fuel at the maximum estimated content, the cumulative injection volume is counted, and the relationship between the cumulative injection volume and the sum of the volume of the oil pipe and the oil rail is determined. After the cumulative injection volume is greater than the sum of the volume of the oil pipe and the oil rail, the actual air-fuel ratio in the engine is obtained after a first preset time interval. The preset time interval is the time interval between the flexible tank spraying the first fuel at the maximum estimated content and the cumulative injection volume being greater than the sum of the volume of the oil pipe and the oil rail.

[0060] In step S300, the theoretical air-fuel ratio is obtained.

[0061] The theoretical air-fuel ratio can be the air-fuel ratio caused by the first fueling condition, and the first fueling condition is that the actual fueling fuel is the second fuel but the injection is calculated according to the first fuel. The theoretical air-fuel ratio can also be the air-fuel ratio caused by the second fueling condition, and the second fueling condition is that the actual fueling fuel is the first fuel and the injection is calculated according to the first fuel. The calculation method of the theoretical air-fuel ratio makes the specific value of the theoretical air-fuel ratio correspond to the corresponding fueling condition.

[0062] In one embodiment, the first fuel is methanol, the second fuel is gasoline, and the theoretical air-fuel ratio is the air-fuel ratio when the actual fueling fuel is gasoline but the injection is controlled according to the fueling fuel being methanol (the maximum value of the mass ratio of methanol).

[0063] In another embodiment, the first fuel is methanol, the second fuel is gasoline, and the theoretical air-fuel ratio is the air-fuel ratio when the actual fueling fuel is methanol and the injection is controlled according to the fueling fuel being methanol.

[0064] In another embodiment, the first fuel is methanol, the second fuel is gasoline, and the theoretical air-fuel ratio is the air-fuel ratio when the actual fueling fuel is methanol and the injection is controlled according to the fueling fuel being methanol.

[0065] In another embodiment, the first fuel is methanol, the second fuel is gasoline, and the theoretical air-fuel ratio is the air-fuel ratio when the actual fueling fuel is methanol and the injection is controlled according to the fueling fuel being methanol.

[0066] In step S400, the actual air-fuel ratio is compared with the theoretical air-fuel ratio, and the actual content of the first fuel in the flexible tank after fueling is determined based on the comparison result.

[0067] The corresponding relationship between the theoretical air-fuel ratio and the corresponding refueling condition is established by a calculation method of the theoretical air-fuel ratio. The actual air-fuel ratio is compared with the theoretical air-fuel ratio. If the two are close to each other, it indicates that the actual refueling condition is consistent with the refueling condition corresponding to the theoretical air-fuel ratio. If the two are far from each other, it indicates that the actual refueling condition is inconsistent with the refueling condition corresponding to the theoretical air-fuel ratio. Thus, the actual content of the first fuel in the flexible fuel tank after refueling is determined.

[0068] In an optional embodiment, the theoretical air-fuel ratio is an air-fuel ratio calculated by taking the actual refueling fuel as the second fuel but performing fuel injection calculation according to the first fuel. The determination of the actual content of the first fuel in the flexible fuel tank after refueling based on the comparison result in step S400 includes:

[0069] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within a preset threshold range, the minimum estimated content of the first fuel in the flexible fuel tank after refueling generated based on the refueling volume is obtained, and it is determined that the actual content of the first fuel is the minimum estimated content of the first fuel.

[0070] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is outside the preset threshold range, it is determined that the actual content of the first fuel is the maximum estimated content of the first fuel.

[0071] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within the preset threshold range, it indicates that the two are close to each other, the actual refueling condition is consistent with the refueling condition corresponding to the theoretical air-fuel ratio, that is, the actual refueling condition is that the actual refueling fuel is the second fuel but fuel injection calculation is performed according to the first fuel. At this time, it can be determined that the fuel for this refueling is the second fuel, and the actual content of the first fuel after refueling is the minimum estimated content.

[0072] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is outside the preset threshold range, it indicates that the two are far from each other, the actual refueling condition is inconsistent with the refueling condition corresponding to the theoretical air-fuel ratio, that is, the actual refueling condition is that the actual refueling fuel is the first fuel and fuel injection calculation is performed according to the first fuel. At this time, it can be determined that the fuel for this refueling is the first fuel, and the actual content of the first fuel after refueling is the maximum estimated content of the first fuel.

[0073] By setting the theoretical air-fuel ratio as an air-fuel ratio calculated by taking the actual refueling fuel as the second fuel but performing fuel injection calculation according to the first fuel, the actual refueling condition is determined according to the difference between the theoretical air-fuel ratio and the actual air-fuel ratio after the comparison between the two, so that the rapid identification of the fuel component is realized.

[0074] In another alternative, the theoretical air-fuel ratio is the air-fuel ratio calculated based on the assumption that the refueling fuel is the first fuel and the refueling is performed according to the first fuel; and the determining of the actual content of the first fuel in the flexible fuel tank after the refueling based on the comparison result in step S400 includes:

[0075] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within a preset threshold range, it is determined that the actual content of the first fuel is the maximum estimated content of the first fuel.

[0076] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is outside the preset threshold range, a minimum estimated content of the first fuel in the flexible fuel tank after the refueling is generated based on the refueling volume, and it is determined that the actual content of the first fuel is the minimum estimated content of the first fuel.

[0077] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within a preset threshold range, it is determined that the actual content of the first fuel is the maximum estimated content of the first fuel.

[0078] When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is outside the preset threshold range, it is determined that the actual content of the first fuel is the minimum estimated content of the first fuel.

[0079] By setting the theoretical air-fuel ratio as the air-fuel ratio calculated based on the assumption that the refueling fuel is the first fuel and the refueling is performed according to the first fuel, and comparing the theoretical air-fuel ratio with the actual air-fuel ratio, the actual refueling situation can be determined according to the difference between the two, thereby realizing the rapid identification of the fuel component.

[0080] Further, the minimum estimated content of the first fuel is calculated as follows:

[0081] The added mass of the second fuel is calculated according to the density of the second fuel and the refueling volume; the total mass of the residual fuel and the residual mass of the first fuel in the flexible fuel tank before the refueling are obtained; and the minimum estimated content of the first fuel is generated based on the added mass of the second fuel, the total mass of the residual fuel, and the residual mass of the first fuel.

[0082] The minimum estimated content of the first fuel corresponds to the content of the first fuel in the flexible tank when the new fuel is the second fuel. Thus, when calculating the minimum estimated content of the first fuel, the added fuel mass, i.e. the added mass of the second fuel, can be calculated according to the density of the second fuel and the refueling volume.

[0083] The total mass of the residual fuel in the flexible tank before refueling can be determined according to the volume of the residual fuel in the flexible tank before refueling and the fuel ratio and the fuel density. The volume of the residual fuel can be obtained by sensor detection and stored before each engine shutdown.

[0084] The residual volume of the first fuel can be determined based on the volume of the residual fuel in the flexible tank before refueling and the fuel ratio, and the residual mass of the first fuel can be determined in combination with the density of the first fuel.

[0085] The residual mass of the first fuel is the total mass of the first fuel in the flexible tank after refueling. The sum of the total mass of the residual fuel in the flexible tank before refueling and the added mass of the second fuel is the total mass of the fuel in the flexible tank after refueling. The ratio of the total mass of the first fuel in the flexible tank after refueling to the total mass of the fuel is calculated as the minimum estimated content of the first fuel.

[0086] By predicting the possible fuel ratio after refueling in advance according to the refueling volume after detecting that the vehicle is refueled, and performing exploratory fuel injection control according to the possible fuel ratio, the air-fuel ratio caused by exploratory fuel injection control is obtained, which is compared with the theoretical air-fuel ratio, and the actual content of the first fuel in the flexible tank after refueling is determined based on the comparison result, so that the rapid acquisition of fuel components is realized without relying on fuel sensors, the development cost is reduced, the self-learning speed is improved, the combustion stability is improved, and the engine shutdown is avoided.

[0087] In another embodiment of the present application, the fuel component identification method of the flexible fuel engine is applied to a vehicle comprising multiple tanks, in addition to the flexible tank, at least one tank, and the equivalence ratio of at least one tank other than the flexible tank is known. For example, there is currently a methanol / gasoline flexible vehicle, and the oil circuit is as shown in the figure, comprising a large tank and a small tank, wherein the large tank, i.e. the flexible tank, can be filled with methanol and gasoline, and the small tank is a gasoline tank for rapid engine start. Figure 2

[0088] Optionally, after the step S200 of controlling the flexible tank to inject fuel according to the maximum estimated content of the first fuel, the method further comprises: controlling at least one tank other than the flexible tank to inject fuel.

[0089] ​The equivalent ratio of the oil tank other than the flexible oil tank is known, and the equivalent ratio does not change abruptly compared with the mixing oil tank, which can be a gasoline tank. For the convenience of description, the oil tank other than the flexible oil tank is referred to as an auxiliary oil tank, and it should be noted that "auxiliary" here is only used to distinguish from the flexible oil tank, and does not represent the limitation of the role of the corresponding oil tank.

[0090] Optionally, after controlling the flexible oil tank to inject oil according to the maximum estimated content of the first fuel, at least one auxiliary oil tank is controlled to inject oil at the same time as the flexible oil tank, and the injected oil participates in combustion in the cylinder.

[0091] Optionally, after controlling the flexible oil tank to inject oil according to the maximum estimated content of the first fuel, at least one auxiliary oil tank is controlled to inject oil after a second preset time interval, and the injected oil participates in combustion in the cylinder, wherein the second preset time interval is less than the preset time length.

[0092] When the flexible oil tank and the auxiliary oil tank inject oil at the same time, the appropriate injection proportion is selected according to the load and the minimum pulse width limit of the injector through calibration.

[0093] Because the flexible oil tank is controlled to inject oil according to the maximum estimated content of the first fuel, the injection is based on an estimated value, and there is a possibility of error, for example, the actual oil added is gasoline, and the actual content of methanol in the flexible oil tank is the minimum estimated content. At this time, injecting oil according to the maximum estimated content of methanol will cause the air-fuel ratio to be too rich, the air-fuel coefficient is small, the ratio of the required gasoline mass of the air in the cylinder of the fully combusting engine to the total mass of the actually injected gasoline of the oil tank is small, and the total mass of the injected gasoline of the oil tank is large, which leads to unstable combustion. Because the equivalent ratio of the auxiliary oil tank is known and fixed, the introduction of the auxiliary oil tank to inject oil to participate in combustion can reduce the mutation degree of the total fuel air-fuel ratio, thereby reducing the adverse effects of fuel instability caused by the mutation of the air-fuel ratio and improving the combustion stability. If the actual added is methanol, the amount of oil injected into the flexible oil tank calculated according to the addition of gasoline will cause the air-fuel ratio to be too lean, and the introduction of the auxiliary oil tank to inject oil to participate in combustion can reduce the degree of air-fuel ratio lean. In addition, the flexible oil tank may experience a sharp fluctuation in air-fuel ratio after adding new fuel, and the introduction of the auxiliary oil tank to participate in combustion can buffer the fluctuation of the air-fuel ratio and reduce the degree of fluctuation of the air-fuel ratio, thereby improving the combustion stability.

[0094] Optionally, after the step S200 of controlling the flexible oil tank to inject oil according to the maximum estimated content of the first fuel, the method further comprises:

[0095] calculating the cumulative injection volume of the flexible oil tank after refueling; specifically, the cumulative injection volume can be calculated by counting the injection volume of the flexible oil tank.

[0096] When the cumulative injection volume is greater than a preset volume, at least one oil tank other than the flexible oil tank is controlled to inject oil.

[0097] For the convenience of description, the oil tank outside the flexible oil tank is referred to as an auxiliary oil tank. It should be noted that "auxiliary" here is only used to distinguish from the flexible oil tank and does not represent a limitation on the role of the corresponding oil tank.

[0098] The preset volume can be a threshold value determined by the user according to development experience.

[0099] By spraying a certain volume of fuel from the flexible oil tank and then controlling the auxiliary oil tank to spray fuel, the fuel injection amount of the auxiliary oil tank can be reduced, and the influence on the auxiliary oil tank can be reduced.

[0100] Optionally, the preset volume is the sum of the volume of the oil pipe and the volume of the oil rail. When the cumulative fuel injection volume is greater than the sum of the volume of the oil pipe and the volume of the oil rail, the newly added fuel in the flexible oil tank begins to affect the combustion process. At this time point, the auxiliary oil tank is introduced to participate in the combustion, so that the auxiliary oil tank can buffer the air-fuel ratio fluctuation introduced by the newly added fuel, and at the same time, the consumption of the auxiliary oil tank can be reduced as much as possible.

[0101] Optionally, the preset time length is the time length from the start of the flexible oil tank spraying fuel with the maximum estimated content of the first fuel to the time when the cumulative fuel injection volume is greater than the sum of the volume of the oil pipe and the volume of the oil rail, and the sum of the first preset time interval. After the flexible oil tank sprays fuel for the preset time length, the auxiliary oil tank stops spraying fuel and exits the combustion. This process has a relatively short time, and the consumption of the auxiliary oil tank can be reduced as much as possible.

[0102] Optionally, the generating the maximum estimated content of the first fuel in the flexible oil tank after refueling according to the refueling volume comprises:

[0103] According to the density of the first fuel and the refueling volume, the added mass of the first fuel is calculated; the total mass of the residual fuel in the flexible oil tank before refueling and the residual mass of the first fuel are obtained; and based on the added mass, the total mass and the residual mass, the maximum estimated content of the first fuel is generated.

[0104] The maximum estimated content of the first fuel corresponds to the content of the first fuel in the flexible oil tank when the newly added fuel is the first fuel. Therefore, when calculating the maximum estimated content of the first fuel, according to the density of the first fuel and the refueling volume, the added fuel mass, i.e. the added mass of the first fuel, can be calculated.

[0105] The total mass of the residual fuel in the flexible oil tank before refueling can be determined by the volume of the residual fuel in the flexible oil tank before refueling and the fuel ratio and the fuel density. The volume of the residual fuel can be obtained by a sensor and stored before each shutdown.

[0106] Based on the volume of the residual fuel in the flexible oil tank before refueling and the fuel ratio, the residual volume of the first fuel can be determined, and in combination with the density of the first fuel, the residual mass of the first fuel can be determined.

[0107] The sum of the newly added mass of the first fuel and the residual mass of the first fuel is the total mass of the first fuel in the flexible fuel tank after refueling. The sum of the total mass of the residual fuel in the flexible fuel tank before refueling and the newly added mass of the first fuel is the total mass of the fuel in the flexible fuel tank after refueling. The ratio of the total mass of the first fuel to the total mass of the fuel in the flexible fuel tank after refueling is calculated as the maximum estimated content of the first fuel.

[0108] The newly added mass of the first fuel is calculated by the density of the first fuel and the refueling volume, and the maximum estimated mass of the first fuel is generated by combining the total mass of the residual fuel in the flexible fuel tank before refueling and the residual mass of the first fuel, so as to realize rough positioning of the first fuel ratio, to facilitate subsequent fuel injection control based on the maximum estimated mass of the first fuel, and further realize fine positioning of the first fuel ratio, thereby realizing rapid identification of fuel components.

[0109] Optionally, the theoretical air-fuel ratio is an air-fuel ratio calculated by taking the first fuel as the refueling fuel; and the obtaining of the theoretical air-fuel ratio comprises:

[0110] The first equivalent ratio of the fuel in the flexible fuel tank after refueling is determined by taking the first fuel as the refueling fuel. That is, the equivalent ratio of the mixed fuel (which can also be pure first fuel) in the flexible fuel tank when the refueling fuel is the first fuel. Here, "first" is only used to distinguish from "second" in the following, and "first" and "second" have no special meaning.

[0111] The in-cylinder intake amount is obtained, and the consumed gas amount of the flexible fuel tank is determined according to the in-cylinder intake amount.

[0112] The in-cylinder intake amount refers to the actual in-cylinder intake amount.

[0113] In an embodiment, the engine has only one flexible fuel tank, and the in-cylinder intake amount is equal to the consumed gas amount of the flexible fuel tank. For example, an ethanol / gasoline flexible fuel engine is configured with one flexible fuel tank, and the actual in-cylinder intake amount is equal to the consumed gas amount of the flexible fuel tank.

[0114] In another embodiment, the engine has two or more fuel tanks, and the consumed gas amount of each fuel tank is determined according to the preset fuel tank fuel injection distribution ratio of each fuel tank.

[0115] The target air-fuel ratio is obtained, and the fuel injection amount corresponding to the first fuel is generated according to the consumed gas amount of the flexible fuel tank, the first equivalent ratio, and the target air-fuel ratio.

[0116] The target air-fuel ratio is a set value, which can be set to 1.

[0117] The theoretical air-fuel ratio is the air-fuel ratio calculated when the actual refueling fuel is the second fuel but the fuel is injected as the first fuel. Therefore, the fuel injection calculation is performed as the first fuel. Specifically, the first equivalence ratio is used as the equivalence ratio of the fuel in the flexible fuel tank after refueling to participate in the calculation of the fuel injection quantity. Combining the gas consumption of the flexible fuel tank, the first equivalence ratio, and the target air-fuel ratio, the fuel injection quantity corresponding to the first fuel is generated. Specifically, the gas consumption of the flexible fuel tank can be divided by the first equivalence ratio and the target air-fuel ratio to obtain the fuel injection quantity corresponding to the first fuel.

[0118] The second equivalence ratio of fuel in the flexible fuel tank after refueling is determined based on the fact that the refueling fuel is the second fuel. That is, when the refueling fuel is the second fuel, the equivalence ratio of the mixed fuel (or pure second fuel) in the flexible fuel tank.

[0119] The mass of the fuel injection is determined based on the injection quantity corresponding to the first fuel and the second equivalence ratio.

[0120] Because the theoretical air-fuel ratio is the air-fuel ratio calculated based on the first fuel but with the second fuel being used for actual refueling, and the actual equivalence ratio of the fuel in the flexible fuel tank after refueling is the second equivalence ratio, the mass of fuel injected from the flexible fuel tank can be calculated based on the injection quantity corresponding to the first fuel and the second equivalence ratio.

[0121] The theoretical air-fuel ratio is generated based on the mass of fuel required to consume the in-cylinder intake air and the mass of the injected fuel.

[0122] The fuel mass required to consume the in-cylinder intake air refers to the fuel mass required to consume the in-cylinder intake air, calculated based on the target air-fuel ratio.

[0123] In one embodiment, if the vehicle has only one flexible fuel tank, the ratio of the mass of fuel required to consume the in-cylinder intake air to the mass of injected fuel is used as the theoretical air-fuel ratio.

[0124] In another embodiment, such as Figure 2 In addition to the methanol / gasoline flexible fuel tank, the vehicle also has a gasoline fuel tank. While calculating the mass of fuel injected for the methanol / gasoline flexible fuel tank, the fuel injection calculation for the gasoline tank is also performed. Specifically, the gas consumption of the gasoline tank is determined based on a preset fuel injection distribution ratio. Combined with the gasoline equivalence ratio and the target air-fuel ratio, the mass of fuel injected for the gasoline tank is generated. The mass of fuel injected for the methanol / gasoline flexible fuel tank is converted into an equivalent mass of gasoline. The sum of this equivalent gasoline mass and the mass of fuel injected for the gasoline tank is calculated. The ratio of the mass of fuel required to consume the in-cylinder intake air to the sum of the fuel injected masses is used as the theoretical air-fuel ratio.

[0125] Optionally, the theoretical air-fuel ratio is an air-fuel ratio calculated according to the first fuel and the first fuel actually added; and the obtaining of the theoretical air-fuel ratio comprises: obtaining a pre-stored theoretical air-fuel ratio. The pre-stored theoretical air-fuel ratio can be set to 1.

[0126] As shown in Figure 3 In an embodiment, the fuel component identification method of the flexible fuel engine is applied to a methanol / gasoline flexible fuel vehicle as shown in Figure 2 The fuel component identification method of the flexible fuel engine comprises:

[0127] When the refueling flag B_refuel is detected to be true, that is, refueling is confirmed, the possible methanol content ratio after refueling is predicted according to the newly added refueling volume: rt_FFPredMin is the minimum value of the methanol mass ratio in the tank after refueling is predicted, and rt_FFPredMax is the maximum value of the methanol mass ratio in the tank after refueling is predicted.

[0128] The flexible tank fuel injection amount is calculated according to the maximum methanol mass ratio rt_FFPredMax and fuel injection is performed, the current cumulative fuel injection volume is calculated according to the actual fuel injection amount, and when the cumulative fuel injection volume is greater than the volume of the fuel pipe and the fuel rail, the newly added fuel begins to affect the combustion process, and this time is recorded as t0. From the time t0, gasoline is introduced to participate in combustion, and according to the load and the minimum pulse width limit of the fuel injector, a suitable injection split ratio rt_splt (optionally 50% methanol oil path and 50% gasoline oil path) is selected through calibration, and the methanol injection amount of the methanol injector is controlled according to the tank methanol ratio rt_FFPredMax.

[0129] The lambda value (air-fuel ratio) caused by the fact that the software calculates the fuel injection amount according to the newly added methanol while the actual added fuel is gasoline is recorded as λ0, and the actual λ is monitored. After a delay, it is judged whether λ0-thd<λ<λ0+thd&λ<1-thd is satisfied, where thd is a set difference value. If yes, it means that the actual λ value monitored by the oxygen sensor is near λ0, and at this time it is considered that the newly added fuel is not methanol, and the methanol content is switched to rt_FFPredMin. If not, it means that the actual λ value monitored by the oxygen sensor is not near λ0, and it is considered that the newly added fuel is methanol, and the methanol content is maintained as rt_FFPredMax.

[0130] The gasoline tank fuel injector is turned off, only the flexible tank fuel injector is turned on, and the fuel component identification method of the flexible fuel engine is exited.

[0131] The computer readable storage medium provided in the embodiment of the present application stores a computer program, and the computer program is read and run by a processor to implement the fuel component identification method of the flexible fuel engine as described above.

[0132] The vehicle provided in the embodiment of the present application comprises a computer readable storage medium storing a computer program and a processor, and the computer program is read and run by the processor to implement the fuel component identification method of the flexible fuel engine as described above. The processor can be implemented as an on-board computer of the vehicle.

[0133] Optionally, the vehicle comprises a flexible fuel tank and at least one auxiliary fuel tank.

[0134] Optionally, the vehicle comprises a methanol / gasoline flexible fuel tank and a gasoline tank.

[0135] It should be understood that each step described in the method embodiment of the present application can be executed in different order and / or in parallel. In addition, the method embodiment can comprise additional steps and / or omit the execution of the steps shown. The scope of the present application is not limited in this respect.

[0136] Although the present disclosure discloses the above, the protection scope of the present disclosure is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications shall fall within the protection scope of the present application.

Claims

1. A method for identifying fuel components in a flexible fuel engine, characterized in that, include: After a refueling operation is detected, the refueling volume is obtained, and the maximum estimated content of the first fuel in the flexible fuel tank after refueling is generated based on the refueling volume. The flexible fuel tank is controlled to inject fuel at the maximum estimated content of the first fuel. After a preset injection time, the actual air-fuel ratio in the engine is obtained, and at least one fuel tank other than the flexible fuel tank is controlled to inject fuel. Obtain the theoretical air-fuel ratio, wherein the theoretical air-fuel ratio is the air-fuel ratio calculated by injecting fuel according to the first fuel when the actual fuel is the second fuel, or the air-fuel ratio calculated by injecting fuel according to the first fuel when the actual fuel is the first fuel. The actual air-fuel ratio is compared with the theoretical air-fuel ratio, and the actual content of the first fuel in the flexible fuel tank after refueling is determined based on the comparison result.

2. The fuel component identification method for a flexible fuel engine as described in claim 1, characterized in that, The determination of the actual content of the first fuel in the flexible fuel tank after refueling based on the comparison results includes: When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within a preset threshold range, the minimum estimated content of the first fuel in the flexible fuel tank after refueling, generated based on the refueling volume, is obtained, and the actual content of the first fuel is determined to be the minimum estimated content of the first fuel. When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is outside the preset threshold range, the actual content of the first fuel is determined to be the maximum estimated content of the first fuel.

3. The fuel component identification method for a flexible fuel engine as described in claim 1, characterized in that, The determination of the actual content of the first fuel in the flexible fuel tank after refueling based on the comparison results includes: When the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is within a preset threshold range, the actual content of the first fuel is determined to be the maximum estimated content of the first fuel. When the actual air-fuel ratio and the theoretical air-fuel ratio are outside the preset threshold range, the minimum estimated content of the first fuel in the flexible fuel tank after refueling, generated based on the refueling volume, is obtained, and the actual content of the first fuel is determined to be the minimum estimated content of the first fuel.

4. The fuel component identification method for a flexible fuel engine as described in claim 1, characterized in that, After controlling the flexible fuel tank to inject fuel at the maximum estimated content of the first fuel, the method further includes: Calculate the cumulative fuel injection volume of the flexible fuel tank after refueling; When the cumulative injection volume is greater than the preset volume, control the injection of oil from at least one oil tank other than the flexible oil tank.

5. The fuel component identification method for a flexible fuel engine as described in claim 4, characterized in that, The preset volume is the sum of the volumes of the oil pipe and the oil rail.

6. The fuel component identification method for a flexible fuel engine as described in claim 1, characterized in that, The step of generating the maximum estimated content of the first fuel in the flexible fuel tank after refueling based on the refueling volume includes: Calculate the additional mass of the first fuel based on the density of the first fuel and the refueling volume; Obtain the total mass of residual fuel in the flexible fuel tank and the residual mass of the first fuel before refueling; Based on the added mass, the total mass, and the residual mass, the maximum estimated content of the first fuel is generated.

7. The fuel component identification method for a flexible fuel engine as described in claim 2, characterized in that, The method of obtaining the theoretical air-fuel ratio includes: The first equivalent ratio of fuel in the flexible fuel tank after refueling is determined by using the first fuel as the refueling fuel. Obtain the in-cylinder air intake volume, and determine the air consumption of the flexible fuel tank based on the in-cylinder air intake volume; Obtain the target air-fuel ratio, and generate the injection quantity corresponding to the first fuel based on the gas consumption of the flexible fuel tank, the first equivalence ratio, and the target air-fuel ratio; The second equivalent ratio of fuel in the flexible fuel tank after refueling is determined according to the second fuel being the refueling fuel; The mass of the fuel to be injected is determined based on the injection quantity corresponding to the first fuel and the second equivalence ratio. The theoretical air-fuel ratio is generated based on the mass of fuel required to consume the in-cylinder intake air and the mass of the injected fuel.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is read and executed by a processor to implement the fuel component identification method for a flexible fuel engine as described in any one of claims 1-7.

9. A vehicle, characterized in that, The invention includes a computer-readable storage medium storing a computer program and a processor, the computer program being read and executed by the processor to implement the fuel component identification method for a flexible fuel engine as described in any one of claims 1-7.

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