CN114412651B - Hybrid vehicle and control method and control device for ignition of catalyst thereof - Google Patents
Hybrid vehicle and control method and control device for ignition of catalyst thereof Download PDFInfo
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- CN114412651B CN114412651B CN202111283300.1A CN202111283300A CN114412651B CN 114412651 B CN114412651 B CN 114412651B CN 202111283300 A CN202111283300 A CN 202111283300A CN 114412651 B CN114412651 B CN 114412651B
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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
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
- F02D41/0255—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus to accelerate the warming-up of the exhaust gas treating apparatus at engine start
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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
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
- F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
- F02D41/064—Introducing corrections for particular operating conditions for engine starting or warming up for starting at cold start
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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
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
- F02D41/068—Introducing corrections for particular operating conditions for engine starting or warming up for warming-up
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/62—Hybrid vehicles
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- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Hybrid Electric Vehicles (AREA)
- Control Of Vehicle Engines Or Engines For Specific Uses (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
The invention discloses a hybrid vehicle and a control method and a control device for ignition of a catalyst thereof, wherein the control method comprises the following steps: generating a catalyst light-off control request when the vehicle is detected to meet the set condition; controlling the vehicle to enter a series mode according to the catalyst ignition control request; determining a target engine speed according to the ignition-off activation time and the first mapping relation, and determining a target engine charging power according to the ignition-off activation time and the second mapping relation; controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine; the ignition activation time is the accumulated time after the vehicle is controlled to enter a series mode according to the catalyst ignition control request; the method realizes that the catalyst of the hybrid vehicle rapidly heats up and reduces the discharge amount of harmful gas and particulate matters of the vehicle in the ignition stage.
Description
Technical Field
The application relates to the technical field of hybrid vehicles, in particular to a hybrid vehicle and a control method and a control device for ignition of a catalyst of the hybrid vehicle.
Background
The three-way catalyst is the most important purification device for automobile exhaust emission, and has a direct relationship between the conversion efficiency and temperature of harmful gases such as carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) generated by the operation of an automobile engine. Generally, the light-off temperature of the catalyst refers to the temperature at which the conversion efficiency of the catalyst on harmful gases reaches 50%, and when the temperature of the catalyst is in the range of 400-600 ℃, the conversion efficiency of the catalyst on main harmful gases emitted by an engine can reach more than 90%. Therefore, the method shortens the light-off time of the catalyst, controls and reduces the emission of the engine in the light-off stage of the catalyst, and has important significance for improving the automobile exhaust emission.
The measures for shortening the light-off time of the catalyst of the traditional fuel oil automobile are as follows: the method is characterized in that the hydrocarbon emission and the particulate matter quantity of the catalyst in the ignition stage are reduced by increasing the engine speed, delaying the ignition advance angle, reducing the air-fuel ratio and other control methods, and the catalyst is quickly raised to the working temperature. This manner of controlling catalyst light-off, while beneficial in increasing engine exhaust temperature, results in: the engine has poor speed stability and combustion stability, and the emission of CO and HC and the quantity of PN particles are higher during the light-off period of the catalyst.
For a hybrid vehicle, the power system comprises a driving motor, a generator and an engine, and the three power sources can be combined to output torque at the wheel end according to working conditions so as to drive the vehicle. The combination of the power sources controls the clutch, when the clutch is opened, the vehicle is in a pure electric working mode or a series working mode, and the output torque of the wheel end is provided by a driving motor; when the clutch is engaged, the vehicle is in a parallel operating mode, with wheel-end output torque being provided by both the drive motor and the engine or by the engine alone.
For hybrid vehicles, a control scheme for controlling an engine in a catalyst light-off state to increase the temperature rise speed of a catalyst and reduce harmful gas and particulate matter emissions until the catalyst is ready to be converted is lacking.
Disclosure of Invention
The invention provides a hybrid vehicle and a control method and a control device for ignition of a catalyst thereof, which aim to solve or partially solve the technical problem of how to accelerate the temperature rise of the catalyst and reduce the emission of harmful gases and particulate matters in the ignition stage of the hybrid vehicle.
To solve the above technical problem, according to an alternative embodiment of the present invention, there is provided a method of controlling light-off of a catalyst of a hybrid vehicle, including:
generating a catalyst light-off control request when detecting that the vehicle meets the set conditions;
controlling the vehicle to enter a series mode according to the catalyst ignition control request;
determining a target engine speed according to the ignition activation time and the first mapping relation, and determining a target engine charging power according to the ignition activation time and the second mapping relation; controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine;
the ignition activation time is the accumulated time after the host vehicle is controlled to enter the series mode according to the catalyst ignition control request; the first mapping relation is a first corresponding relation between the ignition activation time and the engine speed, and the second mapping relation is a second corresponding relation between the ignition activation time and the engine charging power.
Optionally, the determining the target engine speed according to the light-off activation time and the first mapping relationship includes:
when the ignition activation time is less than or equal to a first set time, determining a first engine speed according to the ignition activation time and the first mapping relation, and taking the first engine speed as the engine target speed;
when the ignition activation time is longer than the first set time, determining a second engine speed according to the ignition activation time and the first mapping relation, and taking the second engine speed as the target engine speed;
wherein the value range of the first set time is 15-25 seconds; the first engine speed is greater than the second engine speed.
Further, the value range of the first engine speed is 1200-1400 rpm, and the value range of the second engine speed is 1100-1300 rpm.
Optionally, the determining the target charging power of the engine according to the light-off activation time and the second mapping relationship includes:
when the ignition activation time is less than or equal to a second set time, determining a first charging power according to the ignition activation time and the second mapping relation, and taking the first charging power as the target charging power of the engine;
when the ignition activation time is larger than the second set time, determining second charging power according to the ignition activation time and the second mapping relation, and taking the second charging power as the target charging power of the engine;
wherein the value range of the second set time is 8-12 seconds; the first charging power is less than the second charging power.
Optionally, the setting conditions include:
the difference value between the actual electric quantity and the lowest target electric quantity of the power battery of the vehicle is not lower than a first threshold value; the value range of the first threshold is 0-5%.
Further, the setting of the condition further includes:
the ratio of the torque requested by the driver to the maximum torque of the driving motor is smaller than a second threshold value, and the value range of the second threshold value is 0.85-0.90.
Further, the setting of the condition further includes:
the actual running speed of the vehicle is less than a vehicle speed threshold, and the value range of the vehicle speed threshold is 140-150 km/h.
Further, the setting condition further includes at least one of the following conditions:
the engine of the vehicle is in an inactive state, or the engine is in a non-running state;
detecting a catalyst heating request;
detecting an external start request;
the vehicle working mode of the vehicle is a driving mode.
According to another alternative embodiment of the present invention, there is provided a control apparatus for catalyst light-off of a hybrid vehicle, including:
the catalyst ignition activation module is used for generating a catalyst ignition control request when detecting that the vehicle meets the set conditions;
the whole vehicle mode control module is used for controlling the vehicle to enter a series mode according to the catalyst ignition control request;
the catalyst light-off control module is used for determining the target rotating speed of the engine according to the light-off activation time and the first mapping relation and determining the target charging power of the engine according to the light-off activation time and the second mapping relation; the ignition activation time is the accumulated time after the vehicle is controlled to enter the series mode according to the catalyst ignition control request; the first mapping relation is a first corresponding relation between the ignition activation time and the engine rotation speed, and the second mapping relation is a second corresponding relation between the ignition activation time and the engine charging power; and controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine.
According to yet another alternative embodiment of the present invention, there is provided a hybrid vehicle, the controller of which is programmed to implement the steps of the control method of any one of the preceding claims.
Through one or more technical schemes of the invention, the invention has the following beneficial effects or advantages:
the invention discloses a catalyst light-off control method of a hybrid vehicle, which comprises the steps of generating a catalyst light-off control request when a vehicle meets a set condition, and controlling the vehicle to enter a series mode; the engine enters the series mode because the rotation speed control of the engine in the ignition stage needs a generator (P1 motor) to participate in speed regulation; then determining a target rotating speed of the engine according to the ignition activation time and the first mapping relation, and determining a target charging power of the engine according to the ignition activation time and the second mapping relation; the activation time is the accumulated time for the vehicle to enter a series mode, namely, enter the ignition control of the catalytic converter according to the ignition control request; at the moment, according to the ignition activation time and the first mapping relation, the target rotating speed of the engine in the ignition stage, which is related to the ignition activation time, is set, so that the rapid temperature rise of the catalyst and the improvement of the rotating speed stability of the engine are facilitated; setting target charging power of the engine in the ignition stage, which is associated with the ignition activation time, according to the ignition activation time and the second mapping relation; the difference between the traditional scheme and the traditional scheme is that the target charging power is kept constant under different battery state of charge (SOC) and does not change along with the change of the difference value between the actual SOC and the target SOC, so that the working load of the engine is ensured to be constant in the ignition stage, and large-amplitude fluctuation is avoided, and the particulate matter emission and NVH performance in the ignition stage are improved; through the combination of the two aspects, the catalyst is heated rapidly, and meanwhile, the emission of harmful gases and particulate matters of the vehicle in the ignition stage is reduced.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 illustrates a schematic diagram of a hybrid control architecture for a hybrid vehicle according to one embodiment of the present invention;
FIG. 2 is a schematic flow chart illustrating a method of controlling catalyst light-off according to one embodiment of the present disclosure;
FIG. 3 illustrates a schematic diagram of logic for controlling vehicle operating modes, according to one embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a first mapping of catalyst light-off activation time to engine speed, according to an embodiment of the invention;
FIG. 5 is a graphical illustration of a second mapping of catalyst light-off activation time to engine charging power, according to an embodiment of the invention;
FIG. 6 is a schematic diagram illustrating a detailed logical decision of a catalyst light-off control method according to an embodiment of the present disclosure;
fig. 7 shows a schematic diagram of a control device for catalyst light-off according to another embodiment of the invention.
Detailed Description
In order to make the present application more clearly understood by those skilled in the art to which the present application pertains, the following detailed description of the present application is made with reference to the accompanying drawings by way of specific embodiments. Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control. Unless otherwise specifically indicated, various devices and the like used in the present invention may be commercially available or may be prepared by existing methods.
In order to solve the technical problem that harmful gas and particulate matter emission in the ignition stage is reduced while the temperature rise speed of a catalyst of a hybrid vehicle is accelerated, the invention provides a control method for ignition of the catalyst of the hybrid vehicle, which has the following overall thought:
generating a catalyst light-off control request when the vehicle is detected to meet the set condition; controlling the vehicle to enter a series mode according to the catalyst light-off control request; determining a target engine speed according to the ignition-off activation time and the first mapping relation, and determining a target engine charging power according to the ignition-off activation time and the second mapping relation; controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine; the ignition activation time is the accumulated time after the host vehicle is controlled to enter the series mode according to the catalyst ignition control request; the first mapping relation is a first corresponding relation between the ignition activation time and the engine speed, and the second mapping relation is a second corresponding relation between the ignition activation time and the engine charging power.
The principle of the solution problem of the scheme is as follows: when the vehicle meets the set conditions, a catalyst light-off control request is generated, and the vehicle is controlled to enter a series mode; the engine enters the series mode because the rotation speed control of the engine in the ignition stage needs a generator (P1 motor) to participate in speed regulation; then determining a target rotating speed of the engine according to the ignition activation time and the first mapping relation, and determining a target charging power of the engine according to the ignition activation time and the second mapping relation; the activation time is the accumulated time for the vehicle to enter a series mode and enter the catalyst ignition control according to the ignition control request; at the moment, according to the ignition activation time and the first mapping relation, the target rotating speed of the engine in the ignition stage, which is related to the ignition activation time, is set, so that the rapid temperature rise of the catalyst and the improvement of the rotating speed stability of the engine are facilitated; setting a target charging power of the engine in the ignition stage, which is associated with the ignition activation time, according to the ignition activation time and the second mapping relation; the difference from the traditional scheme is that the target charging power is kept constant under different battery states of charge (SOC) and does not change along with the change of the difference value between the actual SOC and the target SOC, so that the working load of the engine is kept constant in the ignition stage, and large-amplitude fluctuation is avoided, and the particulate matter emission and NVH performance in the ignition stage are improved.
The above-described embodiment will be described in detail with reference to the following embodiments.
Before explaining the concept, it is necessary to briefly describe the power control principle of the hybrid vehicle. FIG. 1 shows a schematic power coupling of a hybrid vehicle, in which an engine is directly connected to an engine at a fixed speed ratio, a control clutch is opened in a series mode, the engine continuously operates in a high-efficiency region after starting, the engine does not directly participate in driving, and only participates in power generation, and a battery is generated by driving a generator; the driving mode of the vehicle is as follows: the driving motor drives the vehicle independently and drives the whole vehicle to run as a power source of the whole vehicle;
in the parallel mode, the internal combustion engine and the motor are connected into a driving system through mechanical connection, and the clutch is combined to respectively drive or jointly drive; the driving mode of the vehicle is as follows: the P3 motor is driven simultaneously with the engine or the engine is directly driven separately. The opening and closing of the clutch is controlled by a VCU (vehicle control unit), which is implemented by means of an HTCU (hybrid transmission control unit) controller.
Further, when the State Of Charge (SOC, state Of Charge, value range Of 0-100%) Of the power battery is high or the power torque required by the driver is small, and the control condition Of entering the pure electric mode (for example, the vehicle speed is lower than a certain value) is met, the clutch can be controlled to be opened, and the power is provided by the driving motor; after the vehicle runs in the pure electric mode for a period of time, when the SOC of the power battery is lower than a certain threshold value, the vehicle enters a series mode, the engine drives the generator to generate electricity to charge the power battery, and the generated power of the engine is calculated according to parameters such as the SOC of the power battery and the like and in combination with various limiting conditions such as the output power of the engine, the emission of cold machine particles, the efficient working rotating speed interval of the generator, the vibration and noise and vibration roughness (NVH) of the whole vehicle and the like. The VCU then calculates the Generator speed set point and the Engine torque request based on the generated power, and finally sends a speed Control command and a speed set point and a demand torque signal to a Generator Controller (GCU) and an Engine torque request and a speed request to an Engine Controller (ECU) via a can bus Engine.
Based on the power control principle of the hybrid vehicle, in an optional embodiment, as shown in fig. 2, a method for controlling the light-off of the catalyst of the hybrid vehicle is provided, and is applied to a vehicle control unit VCU or a vehicle electronic control unit VECU, and specifically includes the following steps:
s201: generating a catalyst light-off control request when detecting that the vehicle meets the set conditions;
specifically, the set condition is a determination condition for determining whether or not there is a catalyst light-off control request from the engine to cause the hybrid vehicle to enter the catalyst light-off control mode. The set conditions stipulate a proper catalyst light-off boundary, and the accuracy of catalyst light-off control is guaranteed. When the host vehicle satisfies the set condition, a catalyst light-off control request is generated.
In some optional embodiments, the setting condition includes:
condition 1: the difference value between the actual electric quantity and the lowest target electric quantity of the power battery of the vehicle is not lower than a first threshold value B; the value range of the first threshold value B is 0-5%.
The power battery is also called as a high-voltage battery, and the minimum target electric quantity A of the power battery refers to the minimum electric quantity which the power battery needs to maintain in order to ensure normal driving of the vehicle and battery health. The actual electric quantity of the power battery can be acquired from a battery management system in real time; while different brands of batteries have different minimum target charge values available from the corresponding suppliers. For example, the minimum target charge A of some power batteries is 30-35%; the present embodiment does not limit the minimum target charge amount of the power battery.
The condition 1 specifies that the current actual electric quantity of the power battery cannot be lower than the lowest target electric quantity and should be higher than 0-5% of the lowest target electric quantity. This is so because the charging efficiency of the power battery is low during the catalyst light-off phase compared to the normal operating mode; if the vehicle is in the catalyst ignition control, but the actual SOC is close to the lowest limit value (the difference value between the actual SOC and the lowest limit value is smaller than the first threshold value), the vehicle directly exits from the catalyst ignition control mode, so that the main relay of the vehicle is prevented from being disconnected and the vehicle cannot be subjected to high voltage.
In some optional embodiments, the setting the condition further includes:
condition 2: the ratio of the torque requested by the driver to the maximum torque of the driving motor is smaller than a second threshold value F, and the value range of the second threshold value F is 0.85-0.90.
The driver request torque can be determined according to the opening degree of an accelerator pedal, and the maximum torque of the driving motor refers to the maximum torque capacity which can be provided by the driving motor. Condition 2 requires that entry into the catalyst light-off control mode be permitted when the driver requested torque does not exceed 85% -90% of the maximum torque of the drive motor. If the catalyst light-off control mode is entered, the ratio of the driver request torque to the maximum torque capacity of the driving motor is larger than a second threshold value, and the duration of the time larger than the second threshold value exceeds a set time threshold value, the exit condition is met, the catalyst light-off control mode is exited, and the driver request torque exceeds a large part of the driving electric torque capacity and is forbidden. Optionally, the time threshold E is set to 0 to 0.05 seconds.
For example, if the maximum torque capacity of the drive motor is 100Nm, and the driver's required torque at this time is 90Nm, the driver uses 90% of the torque capacity. If the second threshold F at this time is 0.85, the catalyst light-off phase will be exited.
The reason why the judgment of the condition 2 is provided is that: in the catalyst light-off stage, because the ignition advance angle is more postponed, the engine output torque can not be normally output and is limited, if the torque required by a driver is larger, the torque can not be met by a driving motor, the required torque of the driver needs to be preferentially met at the moment, and the catalyst light-off control mode needs to be quitted.
In some optional embodiments, the setting condition further includes:
condition 3: the actual running speed of the vehicle is less than a vehicle speed threshold value C, and the value range of the vehicle speed threshold value C is 140-150 km/h.
Condition 3 specifies that entry into the catalyst light-off control mode is permitted at a travel speed of the host vehicle of less than 140 to 150km/h. The purpose of the design is as follows: the maximum vehicle speed is ensured when the catalyst is heated.
In some optional embodiments, the setting condition further includes at least one of the following conditions:
condition 4: the engine of the host vehicle is in an inactive state, or the engine is in a non-operating state. The engine inactive or non-operating state indicates that the engine is not started at this time.
Condition 5: the host vehicle has a catalyst heating request.
Specifically, when the temperature of the engine coolant and the atmospheric pressure are within certain preset ranges, the vehicle control unit requests the catalyst to be heated.
Condition 6: detecting an external start request;
for example, the system may determine that the host vehicle has an external start request signal by detecting at least one of the following conditions:
when the SOC of the high-voltage/power battery is lower than a certain threshold value;
or the water temperature of the engine is lower than a certain threshold value;
or the opening degree of the accelerator is larger than a certain threshold value;
alternatively, the required torque exceeds the capability range of the P3 motor, requesting the start of the engine.
Condition 7: the vehicle working mode of the vehicle is a driving mode.
Condition 7 defines that catalyst light-off control is only permitted to be entered when the vehicle is in a drive mode; the drive mode represents a state when a propulsion system of the vehicle is active. If the vehicle working mode is in other modes, the catalyst light-off control mode is not entered. Examples of other modes are: shutdown, post-operation, standby, charging mode, etc.; the meaning of these modes is:
closing: default safe state, vehicle off;
and (3) post-operation: a post-run state, an overtime state;
standby: active state, no action;
charging: a state when the vehicle is charged using the external energy source.
S202: controlling the vehicle to enter a series mode according to the catalyst light-off control request;
according to step S201, when it is determined that there is a catalyst light-off request from the engine, since the engine light-off speed control requires the P1 motor to participate in speed regulation, the vehicle is allowed to enter the series mode, and the vehicle is not allowed to enter the parallel mode. When the engine has no catalyst light-off request, the vehicle working mode is not limited, and the vehicle is allowed to enter a series mode or a parallel mode.
The logic decision diagram of the above process is shown in fig. 3.
S203: determining a target engine speed according to the ignition activation time and the first mapping relation, and determining a target engine charging power according to the ignition activation time and the second mapping relation; and controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine.
Specifically, the ignition activation time is the accumulated time after the host vehicle is controlled to enter the series mode according to the catalyst ignition control request; the first mapping relation is determined in a vehicle calibration test, and the first corresponding relation between the ignition activation time and the engine speed is determined; the second mapping relation is determined in a vehicle calibration test, and the second corresponding relation between the ignition activation time and the engine charging power
In some alternative embodiments, as shown in fig. 4, the determining the target engine speed based on the light-off activation time and the first map includes:
when the ignition activation time is less than or equal to a first set time, determining a first engine speed by combining a first mapping relation; determining a second engine speed in combination with a first mapping relationship when the light-off activation time is greater than the first set time; the value range of the first set time is 15-25 seconds. Optionally, the first engine speed ranges from 1200 to 1400 rpm, and the second engine speed ranges from 1100 to 1300 rpm.
Further, when the ignition activation time is more than 70-80 seconds, determining the rotating speed of a third engine; the third engine speed is an idle speed.
The reason why the engine speed is determined according to the difference of the ignition activation time is that research finds that a higher catalyst ignition speed (namely the engine speed) is requested at the initial stage of the catalyst ignition, which is beneficial to the improvement of the heat of the engine and the stability of the engine speed; after the catalyst is started and operated for a period of time (such as 21 seconds), the starting rotation speed of the catalyst is reduced, and oil consumption is saved.
Preferably, the preferred target speed control of the engine in the catalyst light-off control mode is as shown in table 1:
table 1: engine target speed setting based on catalyst light-off activation time
In some optional embodiments, the determining an engine target charging power based on the light-off activation time and the second mapping relationship comprises:
when the ignition activation time is less than or equal to a second set time, determining a first charging power according to the ignition activation time and the second mapping relation, and taking the first charging power as the target charging power of the engine; when the ignition activation time is larger than the second set time, determining second charging power according to the ignition activation time and the second mapping relation, and taking the second charging power as the target charging power of the engine; wherein the value range of the second set time is 8-12 seconds; the first charging power is less than the second charging power.
Optionally, the first charging power ranges from-1.2 kW to-3.3 kW, the second charging power ranges from-3.3 kW to-4 kW, and the negative sign indicates that the power is the charging power.
The reason why the control is performed according to the scheme is that the engine is in a cold state at the beginning stage of the catalyst light-off, the internal friction resistance is large, and extra torque needs to be added to maintain the stable engine speed. Therefore, in the catalyst ignition starting stage (before the catalyst ignition activation time reaches the second set time, such as the time period of 0-10 seconds), a smaller catalyst ignition power (namely engine charging power) is requested to reduce the engine load and maintain the stable rotating speed, and after the catalyst ignition starting stage operates for a period of time (after the ignition activation time exceeds the second set time, such as after the catalyst ignition activation time is more than 10 s), the larger ignition power is adopted to maintain the stable ignition power and alleviate the NVH problem.
Preferably, the target charging power of the engine is determined according to the light-off power Map data given in fig. 5 or table 2 below. In table 2, the SOC difference represents the difference between the current actual electric quantity of the power battery and the target electric quantity, which is the electric quantity range that the power battery needs to maintain when the vehicle is running normally. The value of the engine power is negative, which indicates that the engine drives the generator to generate power in the series mode.
Table 2: representation of mapping relation between catalyst light-off activation time and engine charging power
In table 2, the reason why the ignition power is set to a constant value under different SOC difference values is that the current mass production vehicle is set to a large value due to the problem of ignition NVH, and the GCU torque can be increased by requesting a large charging power in the ignition phase, so as to avoid the low torque region, ensure the torque accuracy in the high torque region, and facilitate the rotational speed stability. Although the normal control is to determine the charging power according to the difference between the actual electric quantity and the target electric quantity, in the ignition stage, if the charging power is determined by the difference between the actual electric quantity and the target electric quantity, the charging load of the engine in the ignition stage is too large, the combustion stability is deteriorated, and the like, and further the cold machine gas emission and the particulate matter emission are increased. Therefore, the charging load at the light-off period needs to be a relative fixed value, rather than controlling the large light-off power when the actual electric quantity is low and reducing the light-off power when the actual electric quantity approaches the target electric quantity, according to the difference between the actual electric quantity and the target electric quantity.
According to the method, through a calibration test, the NVH problem caused by low torque precision of the generator is considered, the proper charging speed and charging power of the engine are fixed, the ignition angle can be further combined, measures such as engine required air-fuel ratio reduction and the like can be taken, the temperature rise rate of the catalytic converter can be increased, the emission of cold machine particles in the ignition stage is reduced, and the NVH performance of the ignition stage is improved. The NVH problem is caused here by: the P1 motor (generator) of low rotational speed low power moment of torsion precision is not enough, and generator speed governing stability is poor, leads to the mutual anomaly of moment of torsion between engine moment of torsion and the P1 motor, and then causes the rotational speed undulant, because the P1 motor directly links with the engine, the tooth sound of beating of gearbox appears in the rotational speed fluctuation range greatly.
With reference to the above detailed schemes, a corresponding logic judgment schematic diagram is shown in fig. 6.
The control method for the catalyst light-off provided by the embodiment judges whether the hybrid electric vehicle carries out a catalyst light-off control mode; when the hybrid electric vehicle is in the catalyst ignition control state, the catalyst ignition target rotating speed is set according to the catalyst ignition activation time, and the ignition stage required power is set according to the catalyst ignition activation time, so that the control has the following beneficial effects:
1) Setting a reasonable catalyst light-off control boundary by setting conditions;
2) Setting different target rotating speeds of the engine based on the ignition time, and simultaneously increasing the rotating speed of the engine at the cold stage of the engine, thereby being beneficial to the rapid temperature rise of the catalytic converter and the improvement of the rotating speed stability;
3) Based on the combination of the ignition time and a calibration test, corresponding engine ignition power (engine charging power) is set, and the engine ignition power is kept stable under the condition of different differences between the actual SOC and the target SOC, so that the working load of the engine is constant in the ignition stage, and large-amplitude fluctuation is avoided, thereby being beneficial to improving the emission of harmful gases and particles and the NVH performance in the ignition stage.
In summary, the above method achieves controlling the engine in a better manner to reduce emissions as much as possible, improve speed stability and NVH performance, etc., until the catalyst is ready for a transition, while the hybrid vehicle is in the catalyst light-off state.
Based on the same inventive concept as the previous embodiment, in another alternative embodiment, as shown in fig. 7, there is provided a control apparatus for catalyst light-off of a hybrid vehicle, including:
a catalyst light-off activation module 710 for generating a catalyst light-off control request upon detecting that the host vehicle satisfies a set condition;
the whole vehicle mode control module 720 is used for controlling the vehicle to enter a series mode according to the catalyst ignition control request;
the catalyst light-off control module 730 is used for determining an engine target rotating speed according to the light-off activation time and the first mapping relation and determining an engine target charging power according to the light-off activation time and the second mapping relation; the ignition activation time is the accumulated time after the host vehicle is controlled to enter the series mode according to the catalyst ignition control request; the first mapping relation is a first corresponding relation between the ignition activation time and the engine rotation speed, and the second mapping relation is a second corresponding relation between the ignition activation time and the engine charging power; and controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine.
Specifically, the catalyst light-off activation module 710, the entire vehicle mode control module 720 and the catalyst light-off control module 730 are all enabled by an entire vehicle electronic control unit VECU, and in a hybrid vehicle, the VECU is the integration of an entire vehicle controller VCU and an engine management system EMS.
Optionally, the catalyst light-off control module 730 is configured to:
when the ignition activation time is less than or equal to a first set time, determining a first engine speed according to the ignition activation time and the first mapping relation, and taking the first engine speed as the engine target speed;
when the ignition activation time is longer than the first set time, determining a second engine speed according to the ignition activation time and the first mapping relation, and taking the second engine speed as the target engine speed;
wherein the value range of the first set time is 15-25 seconds; the first engine speed is greater than the second engine speed.
Further, the first engine speed ranges from 1200 to 1400 rpm, and the second engine speed ranges from 1100 to 1300 rpm.
Optionally, the catalyst light-off control module 730 is configured to:
when the ignition activation time is less than or equal to a second set time, determining a first charging power according to the ignition activation time and the second mapping relation, and taking the first charging power as the target charging power of the engine;
when the ignition-off activation time is larger than the second set time, determining second charging power according to the ignition-off activation time and the second mapping relation, and taking the second charging power as the target engine charging power;
wherein the value range of the second set time is 8-12 seconds; the first charging power is less than the second charging power.
Optionally, the setting conditions include:
the difference value between the actual electric quantity of the power battery of the vehicle and the lowest target electric quantity is not lower than a first threshold value; the value range of the first threshold is 0-5%.
Optionally, the setting conditions further include:
the ratio of the torque requested by the driver to the maximum torque of the driving motor is smaller than a second threshold value, and the value range of the second threshold value is 0.85-0.90.
Optionally, the setting condition further includes:
the actual running speed of the vehicle is less than a vehicle speed threshold value, and the value range of the vehicle speed threshold value is 140-150 km/h.
Further, the setting condition further includes at least one of the following conditions:
the engine of the vehicle is in an inactive state, or the engine is in a non-running state;
detecting a catalyst heating request;
detecting an external start request;
the vehicle working mode of the vehicle is a driving mode.
Based on the same inventive concept of the foregoing embodiment, in yet another alternative embodiment, a hybrid vehicle is provided, a controller of which is programmed to implement the steps of the control method in the foregoing embodiment.
Through one or more embodiments of the present invention, the present invention has the following advantageous effects or advantages:
the invention discloses a catalyst light-off control method and a control device of a hybrid vehicle, which generate a catalyst light-off control request and control a vehicle to enter a series mode when the vehicle meets a set condition; the engine enters a series mode because the rotating speed control of the engine in the ignition stage needs a generator (P1 motor) to participate in speed regulation; then determining a target rotating speed of the engine according to the ignition activation time and the first mapping relation, and determining a target charging power of the engine according to the ignition activation time and the second mapping relation; the activation time is the accumulated time for the vehicle to enter a series mode, namely, enter the ignition control of the catalytic converter according to the ignition control request; at the moment, according to the ignition activation time and the first mapping relation, the target rotating speed of the engine in the ignition stage, which is related to the ignition activation time, is set, so that the rapid temperature rise of the catalyst and the improvement of the rotating speed stability of the engine are facilitated; setting a target charging power of the engine in the ignition stage, which is associated with the ignition activation time, according to the ignition activation time and the second mapping relation; the difference between the target charging power and the traditional scheme is that the target charging power is kept constant under different battery state of charge (SOC) and does not change along with the change of the difference value between the actual SOC and the target SOC, so that the working load of an engine is ensured to be constant in the ignition stage, and large-amplitude fluctuation is avoided, and the particulate matter emission and NVH performance in the ignition stage are improved; through the combination of the two aspects, the catalyst is heated rapidly, and meanwhile, the emission of harmful gases and particulate matters of the vehicle in the ignition stage is reduced.
While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the present application.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.
Claims (9)
1. A control method of catalyst light-off of a hybrid vehicle, characterized by comprising:
generating a catalyst light-off control request when detecting that the vehicle meets the set conditions;
controlling the vehicle to enter a series mode according to the catalyst ignition control request;
determining a target engine speed according to the ignition-off activation time and the first mapping relation, and determining a target engine charging power according to the ignition-off activation time and the second mapping relation; controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine;
the ignition activation time is the accumulated time after the vehicle is controlled to enter the series mode according to the catalyst ignition control request; the first mapping relation is a first corresponding relation between the ignition activation time and the engine rotation speed, and the second mapping relation is a second corresponding relation between the ignition activation time and the engine charging power;
the setting conditions include: the difference value between the actual electric quantity of the power battery of the vehicle and the lowest target electric quantity is not lower than a first threshold value; the value range of the first threshold is 0-5%; the minimum target charge A is the minimum charge to be maintained by the power battery.
2. The control method according to claim 1, wherein the determining an engine target speed based on the light-off activation time and the first map includes:
when the ignition-off activation time is less than or equal to a first set time, determining a first engine speed according to the ignition-off activation time and the first mapping relation, and taking the first engine speed as the engine target speed;
when the ignition activation time is longer than the first set time, determining a second engine speed according to the ignition activation time and the first mapping relation, and taking the second engine speed as the target engine speed;
wherein the value range of the first set time is 15-25 seconds; the first engine speed is greater than the second engine speed.
3. The control method of claim 2, wherein the first engine speed ranges from 1200 to 1400 rpm and the second engine speed ranges from 1100 to 1300 rpm.
4. The control method according to claim 1, wherein said determining an engine target charging power based on said light-off activation time and a second mapping relation comprises:
when the ignition-off activation time is less than or equal to a second set time, determining a first charging power according to the ignition-off activation time and the second mapping relation, and taking the first charging power as the target engine charging power;
when the ignition-off activation time is larger than the second set time, determining second charging power according to the ignition-off activation time and the second mapping relation, and taking the second charging power as the target engine charging power;
wherein the value range of the second set time is 8-12 seconds; the first charging power is less than the second charging power.
5. The control method according to claim 1, wherein the setting conditions further include:
the ratio of the torque requested by the driver to the maximum torque of the driving motor is smaller than a second threshold value, and the value range of the second threshold value is 0.85-0.90.
6. The control method according to claim 5, wherein the setting conditions further include:
the actual running speed of the vehicle is less than a vehicle speed threshold, and the value range of the vehicle speed threshold is 140-150 km/h.
7. The control method according to claim 6, wherein the setting condition further includes at least one of the following conditions:
the engine of the vehicle is in an inactive state, or the engine is in a non-running state;
detecting a catalyst heating request;
detecting an external start request;
the vehicle working mode of the vehicle is a driving mode.
8. A control apparatus of catalyst light-off of a hybrid vehicle, characterized by comprising:
the catalyst ignition activation module is used for generating a catalyst ignition control request when detecting that the vehicle meets the set conditions;
the whole vehicle mode control module is used for controlling the vehicle to enter a series mode according to the catalyst ignition control request;
the catalyst light-off control module is used for determining the target rotating speed of the engine according to the light-off activation time and the first mapping relation and determining the target charging power of the engine according to the light-off activation time and the second mapping relation; the ignition activation time is the accumulated time after the host vehicle is controlled to enter the series mode according to the catalyst ignition control request; the first mapping relation is a first corresponding relation between the ignition activation time and the engine rotation speed, and the second mapping relation is a second corresponding relation between the ignition activation time and the engine charging power; controlling the engine of the vehicle according to the target rotating speed of the engine and the target charging power of the engine;
the setting conditions include: the difference value between the actual electric quantity of the power battery of the vehicle and the lowest target electric quantity is not lower than a first threshold value; the value range of the first threshold is 0-5%; the minimum target charge level a is the minimum charge level to be maintained by the power battery.
9. A hybrid vehicle, characterized in that a controller of the hybrid vehicle is programmed for implementing the steps of the control method according to any one of claims 1 to 7.
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| JP2587202B2 (en) * | 1994-08-22 | 1997-03-05 | 本田技研工業株式会社 | Power generation control device for hybrid vehicle |
| JP2000297669A (en) * | 1999-04-12 | 2000-10-24 | Fuji Heavy Ind Ltd | Control device of hybrid vehicle |
| CN100567719C (en) * | 2004-11-04 | 2009-12-09 | 丰田自动车株式会社 | Power take-off and the controlling method that is used for this device |
| DE102011017721A1 (en) * | 2011-04-28 | 2012-10-31 | Robert Bosch Gmbh | Heating an exhaust aftertreatment system by towing an internal combustion engine by means of an electric motor |
| US8475333B2 (en) * | 2011-05-05 | 2013-07-02 | GM Global Technology Operations LLC | Method and apparatus for effecting light-off of a catalytic converter in a hybrid powertrain system |
| GB2498553B (en) * | 2012-01-20 | 2015-07-01 | Jaguar Land Rover Ltd | Improvements in controlling internal combustion engine emissions |
| US8989935B2 (en) * | 2013-03-22 | 2015-03-24 | Ford Global Technologies, Llc | Method and system for engine control |
| JP5874748B2 (en) * | 2013-04-03 | 2016-03-02 | トヨタ自動車株式会社 | Hybrid vehicle control system |
| US11285937B2 (en) * | 2017-12-15 | 2022-03-29 | Nissan Motor Co., Ltd. | Catalyst warm-up control method for hybrid vehicle and catalyst warm-up control apparatus for hybrid vehicle |
| CN110748426B (en) * | 2019-02-25 | 2021-08-20 | 长城汽车股份有限公司 | Catalyst rapid ignition method for vehicle, engine assembly and vehicle |
| JP7207115B2 (en) * | 2019-04-09 | 2023-01-18 | トヨタ自動車株式会社 | hybrid vehicle |
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