CN111691995B - Fuel steam control method and device - Google Patents
Fuel steam control method and device Download PDFInfo
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- CN111691995B CN111691995B CN202010578562.XA CN202010578562A CN111691995B CN 111691995 B CN111691995 B CN 111691995B CN 202010578562 A CN202010578562 A CN 202010578562A CN 111691995 B CN111691995 B CN 111691995B
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- 239000000446 fuel Substances 0.000 title claims abstract description 97
- 238000000034 method Methods 0.000 title claims abstract description 35
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 115
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 109
- 238000001179 sorption measurement Methods 0.000 claims abstract description 18
- 238000011010 flushing procedure Methods 0.000 claims description 38
- 239000002826 coolant Substances 0.000 claims description 30
- 238000002347 injection Methods 0.000 claims description 28
- 239000007924 injection Substances 0.000 claims description 28
- 230000002159 abnormal effect Effects 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims description 8
- 239000004215 Carbon black (E152) Substances 0.000 claims description 2
- 229930195733 hydrocarbon Natural products 0.000 claims description 2
- 150000002430 hydrocarbons Chemical class 0.000 claims description 2
- 239000003921 oil Substances 0.000 description 40
- 239000002828 fuel tank Substances 0.000 description 24
- 238000002485 combustion reaction Methods 0.000 description 20
- 238000003915 air pollution Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 230000009471 action Effects 0.000 description 4
- 239000003610 charcoal Substances 0.000 description 4
- 239000010705 motor oil Substances 0.000 description 4
- 238000003745 diagnosis Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 238000009991 scouring Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 239000003502 gasoline Substances 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000029058 respiratory gaseous exchange Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/003—Adding fuel vapours, e.g. drawn from engine fuel reservoir
- F02D41/0032—Controlling the purging of the canister as a function of the engine operating conditions
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/003—Adding fuel vapours, e.g. drawn from engine fuel reservoir
- F02D41/0032—Controlling the purging of the canister as a function of the engine operating conditions
- F02D41/004—Control of the valve or purge actuator, e.g. duty cycle, closed loop control of position
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
- F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
- F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
- F02M25/0809—Judging failure of purge control system
- F02M25/0827—Judging failure of purge control system by monitoring engine running conditions
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)
Abstract
The application discloses fuel steam control method and device, wherein the fuel steam control method comprises the following steps: acquiring the current oil tank pressure and carbon tank load of a vehicle; judging whether the pressure of the oil tank exceeds a first preset threshold value and whether the load of the carbon canister exceeds a second preset threshold value; when the tank pressure exceeds a first preset threshold or the canister load exceeds a second preset threshold, a valve on the vent line of the canister is opened to flush the canister. The fuel steam control method and the fuel steam control device can avoid the phenomenon of fuel steam overflow caused by carbon canister adsorption overload.
Description
Technical Field
The application relates to the technical field of vehicles, in particular to a fuel steam control method and device.
Background
Because of the volatile property of gasoline, a large amount of fuel vapor is generated in the use process of a traditional fuel vehicle, and the fuel vapor can cause air pollution if being discharged to the atmosphere, so that a fuel vapor control system is required to be installed on the vehicle to control the emission of evaporative pollutants.
The related art generally adsorbs fuel vapor by installing a canister filled with activated carbon between a fuel tank of a fuel-fired vehicle and an engine. After the engine is shut down, fuel steam and fresh air are mixed in the carbon canister and stored in the canister, an exhaust pipeline of the carbon canister is connected with an intake manifold of the engine, after the engine is started, a valve arranged on the exhaust pipeline of the carbon canister is opened, and the fuel steam in the carbon canister is brought into a combustion chamber of the engine by clean air under the action of the vacuum degree of the intake manifold to participate in combustion.
However, in the case of a hybrid vehicle, the vehicle is driven in an electric driving mode for most of the time, which will cause the engine to be inoperative for a long time, and although fuel vapor generated from the fuel tank can be adsorbed by the canister, the adsorption capacity of the canister is limited, and when the adsorption is overloaded, the fuel vapor will overflow to the atmosphere to cause pollution, and may invade into the passenger compartment, resulting in the reduction of the comfort of passengers. If a special pressure-resistant tank or fuel system is used in a hybrid vehicle, the vehicle manufacturer is required to pay a considerable amount for this purpose.
Disclosure of Invention
In order to solve the problems, the application provides a fuel vapor control method and a fuel vapor control device, which can avoid the phenomenon of fuel vapor overflow caused by carbon canister adsorption overload.
The following technical scheme is specifically adopted in the application:
a first aspect of the present application provides a fuel vapor control method, including:
acquiring the current oil tank pressure and carbon tank load of a vehicle;
judging whether the pressure of the oil tank exceeds a first preset threshold value and whether the load of the carbon canister exceeds a second preset threshold value;
and when the oil tank pressure exceeds the first preset threshold or the carbon canister load exceeds the second preset threshold, a valve on an exhaust pipeline of the carbon canister is opened to flush the carbon canister.
Preferably, before the obtaining of the current tank pressure of the vehicle, the method further comprises:
whether a pressure sensor in an oil tank works normally is detected, and when the pressure sensor works normally, the current oil tank pressure of the vehicle is obtained.
Preferably, the opening a valve on an exhaust line of a canister to flush the canister when the tank pressure exceeds a first preset threshold or the canister load exceeds a second preset threshold includes:
when the fact that the pressure of the oil tank exceeds the first preset threshold value or the load of the carbon canister exceeds a second preset threshold value is detected, acquiring the current driving mode of the vehicle;
if the current driving mode of the vehicle is an electric driving mode, switching the current driving mode of the vehicle into an engine running mode, and opening the valve in the engine running mode;
and if the current driving mode of the vehicle is the engine running mode, opening the valve.
Preferably, the engine operating modes include a hybrid drive mode and an engine drive mode.
Preferably, before opening the valve, the method further comprises:
acquiring the current temperature of engine coolant of the vehicle;
when the temperature of the engine coolant is higher than a third preset threshold, the valve is opened.
Preferably, before the current driving mode of the vehicle is obtained, the method further comprises:
detecting whether an electronic fuel injection system of the vehicle works normally;
detecting whether the valve for controlling the exhaust of the carbon canister works normally or not;
and when the electronic injection system and the valve work normally, acquiring the current driving mode of the vehicle.
Preferably, when the pressure sensor or the electronic injection system is detected to be abnormal in operation, the method further comprises the following steps:
switching the current driving mode of the vehicle into an engine running mode at preset intervals;
when the temperature of the engine coolant is higher than a third preset threshold value, a valve on an exhaust pipeline of the carbon tank is opened;
determining a flush duration for the canister based on the canister load;
and when the flushing time is up, closing the valve.
Preferably, the method further comprises:
and when at least one of the pressure sensor, the electronic injection system and the valve is detected to be abnormal, an alarm prompt signal is sent to prompt fault treatment.
Preferably, the method further comprises:
and when the oil tank pressure is lower than a fourth preset threshold value and the carbon canister load is lower than a fifth preset threshold value, closing the valve.
A second aspect of the present application provides a fuel vapor control device, including:
the first acquisition module is used for acquiring the current fuel tank pressure and carbon tank load of a vehicle;
the first judgment module is used for judging whether the pressure of the oil tank exceeds a first preset threshold value and whether the load of the carbon canister exceeds a second preset threshold value;
and the starting module is used for starting a valve on an exhaust pipeline of the carbon canister to flush the carbon canister when the pressure of the oil tank exceeds the first preset threshold or the load of the carbon canister exceeds the second preset threshold.
The beneficial effects brought by the application at least comprise:
the fuel steam control method provided by the application judges whether the current vehicle has the risk of fuel steam overflow and high-pressure operation of the fuel tank by monitoring the fuel tank pressure of the vehicle and calculating whether the load of the carbon canister exceeds the respective preset threshold value, and when any parameter of the fuel tank pressure and the load of the carbon canister exceeds the preset threshold value, a valve for controlling the carbon canister to exhaust is opened, so that the fuel steam stored in the carbon canister is brought into a combustion chamber of an engine by air to participate in combustion, thereby consuming the fuel steam and flushing the carbon canister, avoiding the phenomenon of fuel steam overflow caused by adsorption overload of the carbon canister, and further avoiding air pollution.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a flow chart of a fuel vapor control method provided by an embodiment of the present application;
FIG. 2 is a flow chart of another fuel vapor control method provided by an embodiment of the present application;
FIG. 3 is a flow chart of yet another fuel vapor control method provided by an embodiment of the present application;
fig. 4 is a schematic structural diagram of a fuel vapor control device according to an embodiment of the present application;
FIG. 5 is a schematic structural diagram of another fuel vapor control device according to an embodiment of the present application;
fig. 6 is a schematic structural diagram of another fuel vapor control device according to an embodiment of the present application.
Detailed Description
In order to make the technical solutions and advantages of the present invention clearer, the following will describe the embodiments of the present invention in further detail with reference to the attached drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In this application, the charcoal jar can set up between the oil tank and the engine of vehicle, and wherein the interface of admitting air of charcoal jar passes through the air inlet pipe with the oil tank and is connected, and the exhaust interface of charcoal jar passes through exhaust pipe with the air intake manifold of engine and is connected, is provided with the valve on this exhaust pipe, and the valve can be the solenoid valve, still is provided with the mouth of breathing on the charcoal jar. The carbon canister is filled with activated carbon for adsorbing fuel vapor.
The embodiment of the application provides a fuel vapor Control method, which is generally applied to a hybrid electric vehicle, and an execution main body can be a computer device, and the computer device can be an Electronic Control Unit (ECU). Fig. 1 is a flowchart of a fuel vapor control method according to an embodiment of the present disclosure, and as shown in fig. 1, the method may include the following steps:
and 103, when the pressure of the oil tank exceeds a first preset threshold value or the load of the carbon canister exceeds a second preset threshold value, opening a valve on an exhaust pipeline of the carbon canister to flush the carbon canister.
In summary, the fuel vapor control method provided in the embodiment of the present application determines whether the current vehicle has risks of fuel vapor overflow and high-pressure operation of the fuel tank by monitoring the fuel tank pressure of the vehicle and calculating whether the canister load exceeds the respective preset threshold, and when any one of the fuel tank pressure and the canister load exceeds the preset threshold, opens the valve for controlling the canister to exhaust, so that the fuel vapor stored in the canister is brought into the engine combustion chamber by air to participate in combustion, thereby consuming the fuel vapor and flushing the canister, avoiding the phenomenon of fuel vapor overflow caused by canister adsorption overload, and further avoiding air pollution.
Fig. 2 is a flowchart of another fuel vapor control method provided in an embodiment of the present application, where the fuel vapor control method is generally applied to a hybrid vehicle, and an execution subject may be a computer device, and the computer device may be an ECU. The embodiment of the present application takes an ECU as an example of an execution subject, and the method is described in detail, and as shown in fig. 1, the method may include the following steps:
The embodiment of the application is based on the original hardware configuration of the engine electric control system, the oil tank pressure sensor is additionally arranged, and the oil tank pressure sensor is connected with the ECU. On the premise that the ECU normally works, the vehicle is started to carry out component-level fault diagnosis on the pressure sensor arranged in the oil tank so as to ensure that the pressure sensor works normally and the fed back pressure signal is reasonable and credible. For example, whether there is an open or short circuit phenomenon in the component circuit of the pressure sensor may be detected by the ECU.
If the abnormal work of the oil tank pressure sensor is detected, the pressure signal fed back by the oil tank pressure sensor is indicated to lose the reference value, and the ECU is easy to generate wrong guidance when the engine is controlled to run. In this case, canister flushing can no longer be controlled based on the tank pressure obtained by the ECU. Accordingly, the following control method may be adopted, and as shown in fig. 3, the control method includes steps 2011 to 2014:
2011, switching the current driving mode of the vehicle to an engine running mode every preset time;
the carbon canister of the vehicle absorbs the least fuel steam when each flushing is finished, the fuel steam is absorbed and accumulated again along with the lapse of time, the amount of the fuel steam absorbed by the carbon canister is gradually increased again, and the carbon canister needs to be flushed for the next time until the maximum absorption amount is reached. In the embodiment of the application, the time interval from the end of the flushing to the beginning of the next flushing of the canister of the vehicle is defined as the maximum flushing interval time. The maximum flushing time can be set before the vehicle leaves a factory, and the ECU can predict and adjust the maximum flushing time according to the current state of the vehicle. In some embodiments, the maximum flush interval time may be directly used as the preset time. In other embodiments, the preset time may be set to a time interval less than the maximum washout interval of the vehicle by opening a valve in the exhaust line of the canister to flush the vehicle (i.e., initiate a washout of the canister) only after the vehicle enters the preferred state, taking into account the time that is still required to set the vehicle to the preferred state after the vehicle enters the engine operating mode. The preset time may be set by an operator before the vehicle leaves a factory, or may be automatically generated by the ECU according to the monitored state of the vehicle.
And if the current driving mode of the vehicle is the electric driving mode, the ECU controls the vehicle to switch the current mode into the engine running mode at preset time intervals. The engine running mode refers to a mode in which an engine participates in vehicle driving, and can comprise a hybrid power driving mode and an engine driving mode. If the current driving mode of the vehicle is the engine running mode, switching is not needed.
2012, opening a valve in the exhaust line of the canister when the temperature of the engine coolant is above a third predetermined threshold.
It is also necessary to consider whether the vehicle is currently adapted to immediately open the valve in the exhaust line of the canister after the vehicle has entered the engine-driven mode. For example, if the valve is opened when the engine coolant temperature is relatively low and the viscosity of the engine oil is relatively high, the vehicle enters a flushing condition, which may cause the engine to shake and shut down. Therefore, it is required to reopen the valve after the vehicle meets the following conditions, including: the current temperature of the engine coolant is higher than a third preset threshold, wherein the third preset threshold is the lowest temperature of the coolant under the normal operation of the engine. If the engine operates for a long time at a coolant temperature below the third predetermined threshold, damage may be caused to the engine. The third preset threshold is an empirical value, and the temperature of the third preset threshold may be set to 40 ℃.
After the ECU controls a valve on an exhaust pipeline of the carbon canister to be opened, fuel steam in the carbon canister is brought into a combustion chamber of the engine by air under the action of the vacuum degree of an air inlet manifold to participate in combustion, the carbon canister is flushed, and the residual quantity of the fuel steam absorbed in the carbon canister is reduced.
And 2013, determining the flushing duration of the carbon canister based on the carbon canister load.
The canister load is the concentration of the HC (hydrocarbon) component in the canister, and the ECU can estimate the current canister load of the vehicle by calculation to determine the duration of the canister flush.
When the flushing time of the carbon canister reaches the flushing duration, the ECU can control the valve to be closed; alternatively, the ECU may monitor the canister load and control the valve to close when the canister load is detected to be below a fifth predetermined threshold. The fifth preset threshold value is influenced by factors such as the volume of the carbon canister, the adsorption capacity and the like, and is generally determined by technical personnel according to the type of the carbon canister, and if the load of the carbon canister is lower than the fifth preset threshold value, the HC component concentration in the carbon canister is lower, and the carbon canister has stronger adsorption capacity at present. After the valve is closed, which is equivalent to the vehicle exiting the flushing condition, the ECU may instruct the vehicle to switch the driving mode to the original electric driving mode, and repeat steps 2011-2014.
In some embodiments, when the abnormal operation of the fuel tank pressure sensor is detected, an alarm prompt message can be sent out. For example, a first fault lamp may be provided at an instrument panel of the vehicle, and when a fault of the tank pressure sensor is detected, the first fault lamp may be turned on to prompt a user to process the fault until the fault of the tank pressure sensor is repaired, and then the first fault lamp is turned off.
And if the pressure sensor is detected to work normally, the next step is carried out.
The electronic fuel injection system, i.e. electronic control gasoline injection system, uses ECU as control center, and utilizes various sensors mounted on the engine to measure various running parameters of the engine, then according to the control program prestored in the computer the fuel injection quantity of fuel injector can be accurately controlled, so that the engine can obtain the combustible mixed gas with optimum air-fuel ratio under various working conditions. In the embodiment of the application, whether the electronic fuel injection system has a fault can be detected by the ECU with a fault diagnosis function. If an electronic fuel injection system fails, normal operation of an engine can be affected, and meanwhile, the ECU can generate wrong guidance when the engine is controlled to operate. Therefore, when it is detected that the electronic fuel injection system has a fault, the control strategies described in steps 2011 to 2014 may be applied to the vehicle, and details are not described here.
Correspondingly, when the abnormal work of the electronic fuel injection system is detected, the alarm prompt information can be sent out. For example, a second fault lamp may be provided at an instrument panel of the vehicle, and when a fault of the electronic fuel injection system is detected, the second fault lamp is turned on to prompt a user to treat the fault until the fault of the electronic fuel injection system is repaired and the second fault lamp is turned off.
And if the electronic injection system is detected to work normally, carrying out the next step.
And step 203, detecting whether a valve for controlling the exhaust of the carbon canister works normally.
And a valve for controlling the exhaust of the carbon canister is arranged on the exhaust pipeline of the carbon canister, the opening of the valve indicates that the vehicle enters the flushing working condition, and the closing of the valve indicates that the vehicle exits the flushing working condition. The valve is connected to the ECU and is commanded to open and close by the ECU. The fault detection of the valve can also be completed by the ECU, and on the premise that the ECU works normally, a vehicle is started to perform component-level fault diagnosis on the valve so as to ensure that the valve works normally. If the valve is detected to be in fault, the ECU may not control the opening and closing of the valve, and further cannot control the carbon canister to be flushed. Therefore, when the abnormal work of the valve is detected, the alarm prompt message can be sent out. For example, a third fault lamp may be provided at an instrument panel of the vehicle, and when a valve fault is detected, the third fault lamp may be turned on to prompt a user to treat the fault until the fault of the valve is repaired, and the third fault lamp is turned off.
Wherein, the steps 201 to 203 can be completed at the same time. When the detection is finished and the oil tank pressure sensor, the electronic injection system and the valve are in normal working states, the next step can be executed.
And step 204, acquiring the current fuel tank pressure and carbon tank load of the vehicle.
The following two conditions indicate that the vehicle needs to enter a wash condition:
first, the oil tank can produce a large amount of fuel steam and fill the oil tank because of high temperature or rock, and then leads to the oil tank pressure too high, harms oil tank and oil pump easily. The vehicle is then controlled to enter a flushing condition to reduce the tank pressure.
Secondly, due to the limitation of the capacity and adsorption capacity of the carbon canister, the carbon canister can only adsorb a certain amount of fuel vapor, and once the carbon canister adsorbs overload, the fuel vapor can overflow. At this time, the vehicle needs to be controlled to enter a flushing condition to flush the canister, so that the load of the canister is reduced.
For the above two reasons, it is necessary to monitor the fuel tank pressure and the canister load of the vehicle, and in particular, the current fuel tank pressure and canister load of the vehicle can be obtained by the ECU. In some embodiments, the tank pressure and canister load obtained may be temporarily stored after the tank pressure is obtained.
And step 205, acquiring the current driving mode of the vehicle when detecting that the pressure of the fuel tank exceeds a first preset threshold value or the load of the carbon canister exceeds a second preset threshold value.
Wherein the first preset threshold is a larger value of a normal pressure range in a vehicle oil tank, the threshold can be determined according to the tolerance of the oil tank, and the first preset threshold can be set to be 7.0kPa for a common engine oil tank. The second preset threshold value is also influenced by factors such as the volume and the adsorption capacity of the carbon canister, and can be determined by a technician according to the type of the carbon canister, and is generally slightly lower than the HC component concentration when the carbon canister reaches the fuel vapor adsorption limit, and when the load of the carbon canister is higher than the second preset threshold value, it is indicated that the HC component concentration in the carbon canister is close to the maximum adsorption capacity of the carbon canister, that is, the carbon canister is weak in current adsorption capacity and needs to be flushed as soon as possible.
The carbon canister is flushed, and fuel steam in the carbon canister is brought into a combustion chamber of the engine by air to participate in combustion under the action of negative pressure of an intake manifold. Thus, the engine of the current vehicle is required to be running before the vehicle enters the wash-out condition.
If the obtained current driving mode of the vehicle is the electric driving mode, the engine can be forcibly started to operate, the current driving mode of the vehicle is switched to the engine operating mode, and then the next step is carried out;
if the acquired current driving mode of the vehicle is the engine running mode, the next step can be directly carried out.
The engine running mode comprises a hybrid driving mode and an engine driving mode, the hybrid driving mode refers to the mode that both an engine and a motor do work to drive the vehicle to run, and the engine driving mode refers to the mode that only the engine does work to drive the vehicle to run.
And step 206, acquiring the current temperature of the engine coolant of the vehicle.
After the engine is started, whether the vehicle is at the proper time for entering the scouring condition or not can be judged. For example, if the temperature of the engine coolant is low, the temperature of the engine oil will be reduced, the viscosity of the engine oil will be high, the wear of the parts will increase, the mechanical loss will also increase due to the increased friction resistance, and if the canister is flushed, the torque generated by the combustion during the engine operation will not be sufficient to overcome the friction resistance, causing the engine to shake out, and thus the vehicle cannot be indicated to enter the flushing condition. In addition, after the temperature of the engine coolant is judged, the engine speed can be continuously judged, and the carbon canister cannot be flushed under the condition that the engine speed is too high or the work is unstable.
And step 207, when the temperature of the engine coolant is higher than a third preset threshold value, opening the valve.
When the temperature of the engine coolant is detected to be within a normal working range, the vehicle can be allowed to enter a flushing working condition, and the ECU controls the opening of a valve on an exhaust pipeline of the carbon tank. The third preset threshold is an empirical value, and may be set by an operator before the vehicle leaves a factory.
Accordingly, when the temperature of the engine coolant is detected to be in an abnormal operating range, the vehicle is not allowed to enter a flushing condition, and the valve on the canister exhaust line remains closed. When the temperature of the engine coolant is detected to be within the normal operating range, the vehicle is allowed to open the valve to enter the flushing condition.
In another embodiment, if the vehicle currently has a strong power demand, it needs to meet: when the temperature of the engine coolant is higher than a third preset threshold and the rotating speed of the engine is lower than a sixth preset threshold, the valve can be opened, wherein the sixth preset threshold is the highest rotating speed of the engine in normal operation. The sixth preset threshold is also an empirical value, and may be set to 3000r/min, for example. However, although it is operationally allowed to perform the flushing when the engine coolant temperature is high and the engine speed is low, the safety of the flushing is considered in the actual operating condition, and the unstable combustion caused by inaccurate calculation of the fuel-air ratio is avoided as much as possible, so that the vehicle is indicated to enter the flushing condition in the state where the engine is in the normal operation (including the normal engine coolant temperature range, the normal engine speed range, the engine smooth operation, and the like).
After the vehicle enters a scouring working condition, fuel steam adsorbed by activated carbon in the carbon canister is brought into a combustion chamber of the engine by air under the action of the vacuum degree of the air inlet manifold to participate in combustion, so that the carbon canister is scoured. After the carbon canister is flushed for a period of time, the ECU can send a carbon canister flushing end instruction and control the valve to close so as to exit the flushing working condition.
And step 208, closing the valve when the oil tank pressure is lower than a fourth preset threshold value and the carbon canister load is lower than a fifth preset threshold value.
The fourth preset threshold value is located in a normal pressure range of a vehicle oil tank, specific numerical values can be determined according to tolerance of the oil tank, generally speaking, the fourth preset threshold value can be set to be a smaller value in the normal pressure range of the oil tank, therefore, when the pressure of the oil tank is lower than the fourth preset threshold value, the oil tank is still kept in the normal pressure range, meanwhile, a larger ascending space is provided, and the pressure of the oil tank cannot quickly exceed the first preset threshold value.
If the vehicle receives an instruction for closing the operation of the engine during the flushing working condition, the ECU can not directly close the valve and switch the driving mode into the electric driving mode, but needs to judge whether the carbon tank is allowed to be flushed at present. And the ECU acquires the current oil tank pressure and the carbon canister load, and controls the valve to be closed when the detected oil tank pressure is lower than a fourth preset threshold value and the detected carbon canister load is lower than a fifth preset threshold value, so that the vehicle is out of the flushing working condition. Further, the ECU may control the vehicle to switch the drive mode to the electric drive mode; and when the pressure of the oil tank is detected to be higher than a fourth preset threshold value or the load of the carbon canister is detected to be higher than a fifth preset threshold value, the carbon canister is continuously flushed, and the valve cannot be closed to quit the flushing working condition until the pressure of the oil tank is lower than the fourth preset threshold value and the load of the carbon canister is lower than the fifth preset threshold value.
Further, the ECU may control the vehicle to maintain the current engine operation mode or switch the current engine operation mode to the original electric drive mode. The step of maintaining the current engine mode comprises switching from the current hybrid driving mode to the engine driving mode, switching from the engine driving mode to the hybrid driving mode, and maintaining the current hybrid driving mode or the engine driving mode unchanged.
If the vehicle does not receive the instruction for closing the engine when the pressure of the oil tank is detected to be lower than the fourth preset threshold and the load of the carbon canister is detected to be lower than the fifth preset threshold, the vehicle can be kept in the current flushing working condition, namely the valve is continuously opened, the instruction for closing the engine is waited, and the instruction is executed; the ECU can also be used for actively controlling the valve to close so as to enable the vehicle to exit the scouring condition. Further, the ECU may control the vehicle to maintain the current engine operation mode or switch the current engine operation mode to the original electric drive mode.
According to the fuel steam control method provided by the embodiment of the application, fault detection is performed on components such as a fuel tank pressure sensor, an electronic injection system and a valve before execution, if the components are not in fault, whether the risk of fuel steam overflow and high-pressure operation of a fuel tank exists in a current vehicle is judged by monitoring whether the fuel tank pressure and the carbon canister load of the vehicle exceed respective preset thresholds, when any parameter of the fuel tank pressure and the carbon canister load exceeds the preset threshold, the vehicle is indicated to start an engine to operate, and the valve for controlling the carbon canister to exhaust is opened after the engine runs normally, so that fuel steam stored in the carbon canister is brought into a combustion chamber of the engine by air to participate in combustion, and the fuel steam is consumed and the carbon canister is flushed. If any part is detected to be out of order, an alarm prompt message is sent to prompt maintenance, and after the pressure sensor or the electronic injection system is detected to be out of order, the vehicle is indicated to enter a flushing working condition at preset intervals, so that misguidance of ECU control engine operation is avoided, fuel steam overflow caused by carbon canister adsorption overload is avoided, and air pollution is avoided.
Fig. 4 is a schematic structural diagram of a fuel vapor control device 400 according to an embodiment of the present application. Referring to fig. 4, the apparatus 400 includes:
an obtaining module 401 configured to obtain a current tank pressure and canister load of a vehicle;
a determination module 402 configured to determine whether a tank pressure exceeds a first preset threshold and a canister load exceeds a second preset threshold;
an opening module 403 configured to open a valve on an exhaust line of the canister to flush the canister when the tank pressure exceeds a first preset threshold or the canister load exceeds a second preset threshold.
To sum up, the fuel vapor control device 400 provided by the embodiment of the present application obtains the fuel tank pressure and the canister load of the vehicle through the obtaining module 401, and determines whether the fuel tank pressure and the canister load exceed the corresponding threshold values through the determining module 402, when any parameter of the fuel tank pressure and the canister load exceeds the preset threshold value, the valve for controlling the canister exhaust is opened through the opening module 403, so that the fuel vapor stored in the canister is brought into the engine combustion chamber by the air to participate in the combustion, thereby consuming the fuel vapor and flushing the canister, avoiding the phenomenon that the fuel vapor overflows due to the canister adsorption overload, and further avoiding the air pollution.
Fig. 5 is a schematic structural diagram of another fuel vapor control device 400 provided in the embodiment of the present application, and as shown in fig. 5, on the basis of fig. 4, the device 400 further includes:
a detection module 404 configured to detect whether a pressure sensor inside the tank, an electronic fuel injection system, and a valve controlling canister venting are functioning properly;
in some implementations of the present application, the obtaining module 401 is further configured to obtain a current driving mode of the vehicle when it is detected that the tank pressure exceeds a first preset threshold or the canister load exceeds a second preset threshold.
The determination module 402 is further configured to determine a current driving mode of the vehicle.
The apparatus 400 further comprises:
a switching module 405 configured to switch a current driving mode of the vehicle to an engine operation mode when the current driving mode of the vehicle is an electric driving mode;
in some implementations of the present application, the obtaining module 401 is further configured to obtain a current engine coolant temperature of the vehicle;
the opening module 403 is further configured to open a valve on an exhaust line of the canister when the temperature of the engine coolant is above a third preset threshold;
the apparatus 400 further comprises:
a closing module 406 configured to close a valve on an exhaust line of the canister when the tank pressure is below a fourth preset threshold and the canister load is below a fifth preset threshold.
The shutdown module 406 is further configured to close a valve on an exhaust line of the canister upon receiving an instruction to allow the canister flush to end.
In summary, the fuel vapor control device 400 provided in this embodiment of the present application performs fault detection on components such as a fuel tank pressure sensor, an electronic fuel injection system, and a valve through the detection module 404 before executing the fuel vapor control method, and if none of the components is faulty, switches the current driving mode of the vehicle to the engine operating mode through the switching module 405 by obtaining the fuel tank pressure and the canister load of the vehicle 401, and when any parameter of the fuel tank pressure and the canister load exceeds a preset threshold, opens the valve on the exhaust pipe of the canister through the opening module 403 after the obtaining module 401 obtains that the engine operating state is the normal operating state, so that the fuel vapor stored in the canister is brought into the combustion chamber of the engine by air to participate in combustion, thereby consuming the fuel vapor and flushing the canister, and avoiding the phenomenon of fuel vapor overflow caused by the canister adsorption overload, thereby avoiding air pollution. The shutdown module 406 closes the valve after both the tank pressure and the canister load are below respective thresholds, or after an end of a permitted canister flush is received.
Fig. 6 is a schematic structural diagram of another fuel vapor control device 400 according to an embodiment of the present application, as shown in fig. 6, and based on fig. 5, after the detection module 404 detects that there is a failure in the tank pressure sensor or the electronic fuel injection system:
the switching module 405 is configured to switch the current driving mode of the vehicle to the engine running mode every preset time;
the opening module 403 is configured to open a valve on an exhaust line of the canister when the temperature of the engine coolant is above a third preset threshold;
a determination module 407 configured to determine a flush duration for the canister based on the canister load;
the shut-off module 406 is further configured to close the valve after the flush duration is reached.
Further, the device 400 may further include an alarm module 408, and the alarm module 408 is configured to send an alarm prompt message when any one of the components, i.e., the tank pressure sensor, the electronic fuel injection system, and the valve, is detected to be out of order.
To sum up, if the fuel steam control device provided by the embodiment of the application detects that any one component has a fault, the alarm module 408 sends out an alarm prompt message to prompt maintenance, and after the fault of the pressure sensor or the electronic injection system is detected, the opening module 403 opens the valve on the exhaust pipeline of the canister at preset intervals to enable the vehicle to enter the flushing working condition, so that misguidance of the ECU controlling the engine to operate is avoided, and further the situation that the vehicle does not flush the canister for a long time, so that fuel steam overflows and air pollution is caused is avoided.
With regard to the apparatus in the above-described embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment related to the method, and will not be elaborated here.
The embodiment of the present application also provides a hybrid vehicle including the above-described fuel vapor control apparatus 400.
In the present application, it is to be understood that the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations are not described separately in this application.
The above description is only for facilitating the understanding of the technical solutions of the present application by those skilled in the art, and is not intended to limit the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (3)
1. A fuel vapor control method, characterized by comprising:
acquiring the current carbon tank load of a vehicle;
detecting whether a pressure sensor in the oil tank works normally or not;
detecting whether an electronic fuel injection system of a vehicle works normally;
detecting whether a valve for controlling the exhaust of the carbon tank works normally or not;
when the pressure sensor, the electronic injection system and the valve work normally, the current oil tank pressure of the vehicle is obtained;
judging whether the oil tank pressure exceeds a first preset threshold value and whether the carbon canister load exceeds a second preset threshold value, wherein the first preset threshold value is the maximum value of a normal pressure range in the vehicle oil tank, and the second preset threshold value is lower than the hydrocarbon component concentration when the carbon canister reaches a fuel vapor adsorption limit;
when the oil tank pressure exceeds the first preset threshold or the carbon canister load exceeds the second preset threshold, acquiring a current driving mode of the vehicle, if the current driving mode of the vehicle is an electric driving mode, switching the current driving mode of the vehicle into an engine running mode, acquiring the temperature of engine coolant, when the temperature of the engine coolant is higher than a third preset threshold, opening a valve on an exhaust pipeline of a carbon canister to flush the carbon canister, if the current driving mode of the vehicle is the engine running mode, when the temperature of the engine coolant is higher than the third preset threshold, opening the valve, and when the oil tank pressure is lower than a fourth preset threshold and the carbon canister load is lower than a fifth preset threshold, closing the valve;
when at least one of the pressure sensor and the electronic fuel injection system works abnormally, switching the current driving mode of the vehicle into an engine running mode at preset time intervals;
acquiring the temperature of the engine coolant, and opening a valve on an exhaust pipeline of the carbon canister when the temperature of the engine coolant is higher than a third preset threshold, wherein the third preset threshold is the lowest temperature of the coolant under the normal operation of the engine;
determining a flush duration for the canister based on the canister load;
and when the flushing duration is reached and the load of the carbon canister is detected to be lower than the fifth preset threshold value, closing the valve.
2. The method of claim 1, further comprising:
and when at least one of the pressure sensor, the electronic injection system and the valve is detected to be abnormal, an alarm prompt signal is sent to prompt fault treatment.
3. A fuel vapor control apparatus, characterized by comprising:
the acquisition module is used for acquiring the current oil tank pressure, the temperature of engine coolant and the load of a carbon tank of the vehicle;
the judgment module is used for judging whether the oil tank pressure exceeds a first preset threshold value and whether the carbon canister load exceeds a second preset threshold value, and when the oil tank pressure exceeds the first preset threshold value or the carbon canister load exceeds the second preset threshold value, the acquisition module acquires the current driving mode of the vehicle, wherein the first preset threshold value is the maximum value of a normal pressure range in the oil tank of the vehicle, and the second preset threshold value is lower than the HC component concentration when the carbon canister reaches a fuel vapor adsorption limit;
the starting module is used for starting a valve on an exhaust pipeline of the carbon canister to flush the carbon canister when the pressure of the oil tank exceeds the first preset threshold or the load of the carbon canister exceeds the second preset threshold and when the temperature of the engine coolant is higher than a third preset threshold, wherein the third preset threshold is the lowest temperature of the coolant under the normal operation of the engine;
the detection module is used for detecting whether a pressure sensor, an electronic injection system and a valve for controlling the exhaust of the carbon canister in the oil tank work normally or not;
the device comprises a switching module, a control module and a control module, wherein the switching module switches the current driving mode of the vehicle into an engine running mode when the current driving mode of the vehicle is an electric driving mode;
and the closing module is used for closing a valve on an exhaust pipeline of the carbon canister when the pressure of the oil tank is lower than a fourth preset threshold and the load of the carbon canister is lower than a fifth preset threshold, or closing the valve on the exhaust pipeline of the carbon canister after receiving an instruction for allowing the carbon canister to be flushed.
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| CN202010578562.XA CN111691995B (en) | 2020-06-23 | 2020-06-23 | Fuel steam control method and device |
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| CN202010578562.XA CN111691995B (en) | 2020-06-23 | 2020-06-23 | Fuel steam control method and device |
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| CN111691995B true CN111691995B (en) | 2022-05-03 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114517741A (en) * | 2020-11-20 | 2022-05-20 | 上海汽车集团股份有限公司 | Engine control method and device and engine control system |
| CN114704395B (en) * | 2022-05-19 | 2023-05-09 | 江铃汽车股份有限公司 | Novel fuel evaporation and emission control system and control method |
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