CN114922761A - Control method of start-up auxiliary system and start-up auxiliary system - Google Patents
Control method of start-up auxiliary system and start-up auxiliary system Download PDFInfo
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- CN114922761A CN114922761A CN202210594541.6A CN202210594541A CN114922761A CN 114922761 A CN114922761 A CN 114922761A CN 202210594541 A CN202210594541 A CN 202210594541A CN 114922761 A CN114922761 A CN 114922761A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
- F02N19/00—Starting aids for combustion engines, not otherwise provided for
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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
- F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
- F02M35/10—Air intakes; Induction systems
- F02M35/10209—Fluid connections to the air intake system; their arrangement of pipes, valves or the like
- F02M35/10229—Fluid connections to the air intake system; their arrangement of pipes, valves or the like the intake system acting as a vacuum or overpressure source for auxiliary devices, e.g. brake systems; Vacuum chambers
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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
Abstract
The invention discloses a control method of a start-up auxiliary system and the start-up auxiliary system, and belongs to the technical field of engine start-up auxiliary. The control method of the starting auxiliary system comprises the following steps: s1, when the engine enters a stop state, the control unit sends out a fuel cut-off instruction, and the throttle valve is completely closed; s2, judging whether the pressure in the air inlet manifold is smaller than the pressure in the vacuum air storage tank or not; if yes, opening an electromagnetic valve to enable the vacuum air storage tank to be communicated with the air inlet manifold; s3, immediately closing the electromagnetic valve when the preset working condition is met; s4, judging whether the pressure in the vacuum air storage tank is larger than the maximum allowable pressure value or not; and S5, if yes, starting the vacuumizing unit until the pressure in the vacuum air storage tank is smaller than the maximum allowable pressure value. The proper vacuum degree is ensured to be established in the vacuum air storage tank, and the smooth start of the engine is ensured. Firstly, the vacuum degree is established by using the energy of the engine during the shutdown, and then a vacuum-pumping unit is selected, so that the energy consumption is reduced.
Description
Technical Field
The invention relates to the technical field of engine starting assistance, in particular to a control method of a starting assistance system and the starting assistance system.
Background
For a series configuration hybrid power system mechanism, an engine and a generator are directly connected together through a torsional damper, the engine is ignited after the engine is dragged to a certain rotating speed by the torque output by the generator in the starting process, then the torque of the generator is converted from positive torque to negative torque to generate electricity, and the electric power output by the generator is transmitted to a driving motor to complete the driving of the whole vehicle. In the starting and dragging process, dragging resistance moment comes from the rotational inertia of a crankshaft, a torsional damper, a reduction gear and a generator rotor on one hand, and the compression reaction force of an engine piston on the other hand.
At the present stage, a vacuum air storage tank is installed on an air inlet manifold of an engine, an electromagnetic valve is installed between the vacuum air storage tank and the air inlet manifold, the electromagnetic valve is opened in the shutdown process of the engine, vacuum is built in the vacuum air storage tank through the vacuum of the air inlet manifold, the electromagnetic valve is opened in the startup process, the air in the air inlet manifold is pumped out by utilizing the vacuum degree of the vacuum air storage tank, and therefore the air inflow in a cylinder in the dragging process is reduced.
However, in the process of establishing the vacuum degree of the vacuum storage tank during the shutdown, if the shutdown time is short or the vacuum degree of the intake manifold during the shutdown is insufficient, it is difficult to establish the required vacuum degree of the vacuum storage tank.
Therefore, it is desirable to provide a control method of a start-up assisting system and a start-up assisting system to solve the above problems.
Disclosure of Invention
The invention aims to provide a control method of a starting auxiliary system and the starting auxiliary system, which can ensure that proper vacuum degree is established in a vacuum air storage tank and meet the starting requirement of an engine.
In order to realize the purpose, the following technical scheme is provided:
a control method of a start-up auxiliary system comprises the following steps:
s1, when the engine enters a stop state, the control unit sends out a fuel cut-off instruction, and the throttle valve is completely closed;
s2, judging whether the pressure in the air inlet manifold is smaller than the pressure in the vacuum air storage tank or not; if yes, opening an electromagnetic valve to enable the vacuum air storage tank to be communicated with the air inlet manifold;
s3, when the preset working condition is met, immediately closing the electromagnetic valve;
s4, judging whether the pressure in the vacuum air storage tank is larger than the maximum allowable pressure value;
and S5, if yes, starting the vacuumizing unit until the pressure in the vacuum air storage tank is smaller than the maximum allowable pressure value.
As an alternative to the control method of the start-up assisting system, in step S3, the preset operating condition is that the pressure in the vacuum air tank is smaller than a maximum allowable pressure value; or
The rotating speed of the engine is lower than the sum of the upper limit rotating speed and the error rotating speed of the low-speed resonance region of the engine; or
The pressure within the vacuum reservoir is greater than the maximum allowable pressure value and the pressure within the intake manifold begins to rise.
As an alternative to the control method of the start-up assist system, the vacuum pumping unit is an electric vacuum pump electrically connected to the control unit, and the electric vacuum pump is not allowed to be turned on with the electromagnetic valve kept open.
As an alternative to the control method of the start-up assist system, in step S5, when the performance degradation of the electric vacuum pump is detected, the engine deceleration rate at the time of the stop is reduced, and the engine deceleration time is extended.
As an alternative to the control method of the takeoff assist system, the engine deceleration rate at shutdown is reduced by operating the engine with a generator.
As an alternative to the control method of the lift assist system, in step S5, if the pressure in the vacuum tank does not reach less than the maximum allowable pressure value within the set time, it is determined that the performance of the electric vacuum pump is degraded.
As an alternative to the control method of the start-up assist system, the set time is 1.3 times the time required for the electric vacuum pump to reduce the vacuum reservoir from the initial pressure to the maximum allowable pressure value of the vacuum reservoir.
As an alternative to the control method of the start-up assist system, the initial pressure of the vacuum air tank is the pressure at the instant when the solenoid valve is closed and the electric vacuum pump is turned on in the step S5.
A starting auxiliary system comprises an engine, an air inlet manifold, a throttle valve, a second pressure sensor, a vacuum air storage tank, a third pressure sensor, an electromagnetic valve, a vacuumizing unit and a control unit, wherein the vacuum air storage tank is vacuumized by adopting the control method of the starting auxiliary system.
As an alternative of the starting auxiliary system, the starting auxiliary system further comprises a one-way valve, wherein an inlet of the one-way valve is communicated with the vacuum air storage tank, and an outlet of the one-way valve is communicated with the vacuumizing unit.
Compared with the prior art, the invention has the beneficial effects that:
according to the control method of the starting auxiliary system, when the engine enters a stop state, the control unit sends out an oil cut-off instruction, the throttle valve is completely closed, and because the engine still rotates, the piston still extracts air in the air inlet manifold, the air pressure in the air inlet manifold can be sharply reduced and is far less than the ambient atmospheric pressure; judging whether the pressure in the air inlet manifold is smaller than the pressure in the vacuum air storage tank or not; if so, opening the electromagnetic valve to communicate the vacuum air storage tank with the intake manifold, pumping the air in the vacuum air storage tank into the intake manifold, and rapidly reducing the pressure in the vacuum air storage tank to be gradually the same as the air pressure in the intake manifold; closing the electromagnetic valve when a preset condition is met; under the condition that the electromagnetic valve is closed, judging whether the pressure in the vacuum air storage tank is greater than the maximum allowable pressure value or not; if so, starting the vacuumizing unit until the pressure in the vacuum air storage tank is smaller than the maximum allowable pressure value, ensuring that the proper vacuum degree is established in the vacuum air storage tank, and ensuring that the engine is started smoothly. And firstly, the vacuum degree is established by selecting and using the energy of the engine during the shutdown, and then the vacuum degree is established by selecting the vacuum-pumping unit, thereby reducing the energy consumption.
According to the start-up auxiliary system provided by the invention, the electromagnetic valve is closed when a preset condition is met; under the condition that the electromagnetic valve is closed, judging whether the pressure in the vacuum air storage tank is greater than the maximum allowable pressure value or not; if so, starting the vacuumizing unit until the pressure in the vacuum air storage tank is smaller than the maximum allowable pressure value, and ensuring that proper vacuum degree is established in the vacuum air storage tank, so that the vacuum degree of the vacuum air storage tank can always meet the requirement of smooth start of the engine before the engine is started every time.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.
FIG. 1 is a schematic illustration of a hybrid powertrain according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a start-up assist system in an embodiment of the present invention;
FIG. 3 is a first flowchart of a method for controlling a start-up assist system according to an embodiment of the present invention;
fig. 4 is a second flowchart of a control method of the start-up assist system in the embodiment of the present invention.
Reference numerals are as follows:
1. an engine; 2. a generator; 3. a torsional damper; 4. a reduction gear mechanism; 5. a clutch; 6. a drive motor; 7. a differential mechanism;
11. an intake manifold; 12. a throttle valve; 13. a control unit; 14. an electromagnetic valve; 15. a vacuum gas storage tank; 16. a vacuum pumping unit; 17. a first pressure sensor; 18. a one-way valve; 19. a rotational speed sensor; 20. a turbocharger; 21. a three-way catalyst;
111. a second pressure sensor;
151. a third pressure sensor;
131. an engine controller; 132. a CAN bus; 133. and (5) a vehicle control unit.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that are conventionally placed when the products of the present invention are used, and are used only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements to be referred to must have specific orientations, be constructed in specific orientations, and operate, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
The hybrid powertrain architecture includes, for a series configuration, an engine 1, a generator 2, a torsional damper 3, a reduction gear mechanism 4, a clutch 5, a drive motor 6, and a differential 7, as shown in fig. 1. The engine 1 and the generator 2 are directly connected together through the torsional damper 3, in the starting process, the engine 1 is ignited after the generator 2 outputs torque to drag the engine 1 to a certain rotating speed, then the torque of the generator 1 is converted from positive torque to negative torque to generate electricity, and the electric power output by the generator 1 is transmitted to the driving motor 6 to complete the driving of the whole vehicle. In the starting and dragging process, dragging resistance moment comes from the rotational inertia of the crankshaft-torsion shock absorber 3-reduction gear mechanism 4-generator 2 rotor on one hand, and the compression reaction force of the piston of the engine 1 on the other hand, if the compression reaction force of the piston in the dragging process can be reduced, the dragging speed can be greatly improved, and meanwhile, the torque required by the generator 2 dragging can be reduced. Through the cooperation control of the air throttle of the air intake and exhaust VVT and the engine 1, the actual air intake amount in the cylinder in the dragging process can be reduced to a certain extent, and further the compression counterforce of a piston is reduced, but the VVT driving mechanism is required to be in an electric driving form, the air intake and exhaust VVT of the engine 1 is mostly in a hydraulic driving form, the VVT can not be controlled almost in the starting process, and therefore the actual air intake amount in the cylinder in the dragging process is difficult to effectively reduce only through the air throttle control.
At the present stage, a vacuum air storage tank is arranged on an air inlet manifold of an engine, an electromagnetic valve is arranged between the vacuum air storage tank and the air inlet manifold, the electromagnetic valve is opened in the shutdown process of the engine, vacuum is built in the vacuum air storage tank through the vacuum of the air inlet manifold, the electromagnetic valve is opened in the startup process, and the air in the air inlet manifold is pumped out by utilizing the vacuum degree of the vacuum air storage tank, so that the air input in a cylinder in the dragging process is reduced.
However, in the process of establishing the vacuum degree of the vacuum storage tank during the shutdown, if the shutdown time is short or the vacuum degree of the intake manifold during the shutdown is insufficient, it is difficult to establish the required vacuum degree of the vacuum storage tank.
In order to ensure that a proper vacuum degree is established in the vacuum air storage tank and meet the engine starting requirement, the embodiment further provides a starting auxiliary system, as shown in fig. 2, which comprises the engine 1, the intake manifold 11, the throttle valve 12, the second pressure sensor 111, the vacuum air storage tank 15, the third pressure sensor 151 and the electromagnetic valve 14, and further comprises the vacuum pumping unit 16 and the control unit 13. Wherein one end of the vacuumizing unit 16 is communicated with the vacuum air storage tank 15; the control unit 13 is electrically connected with the vacuum pumping unit 16 and is used for controlling the on-off of the vacuum pumping unit 16. The vacuum air storage tank 15 and the vacuumizing unit 16 form an air extracting-air storage device, and an electric vacuum pump is connected to the rear end of the vacuum air storage tank 15, so that when the vacuum degree of the vacuum air storage tank 15 is difficult to establish only through the vacuum degree of the air inlet manifold 11 in the shutdown process, the vacuum degree of the vacuum air storage tank 15 is established in an auxiliary mode through the air extracting function of the electric vacuum pump, and the vacuum degree of the vacuum air storage tank 15 can always meet the start-up requirement before starting up every time.
Further, the start-up auxiliary system further comprises a check valve 18, and the check valve 18 is arranged on a pipeline between the vacuumizing unit 16 and the vacuum air storage tank 15. Specifically, an inlet of the check valve 18 communicates with the vacuum reservoir 15, and an outlet of the check valve 18 communicates with the vacuum pumping unit 16.
Further, the control unit 13 includes an engine controller 131, a CAN line 132, and a vehicle controller 133.
Further, the engine starting auxiliary system also comprises a rotating speed sensor 19, a turbocharger 20, a three-way catalyst 21 and the first pressure sensor 17.
Specifically, as shown in fig. 2, a throttle valve 12 is mounted on an intake manifold 11 of the engine 1 for controlling the amount of air flowing into the intake manifold 11, the throttle valve 12 is connected to an engine controller 131 by a wire harness, and the engine controller 131 controls the amount of air flowing into the intake manifold 11 by controlling the opening degree of the throttle valve 12; a second pressure sensor 111 of the intake manifold 11 is installed on the intake manifold 11 behind the throttle valve 12 and connected to an engine controller 131 through a wiring harness, and the engine controller 131 collects air pressure in the intake manifold 11 through the second pressure sensor 111; the rotating speed sensor 19 is mounted on a flywheel shell of the engine 1, is connected into the engine controller 131 through a wire harness, and is used for acquiring the crankshaft rotating speed of the engine 1; one end of the electromagnetic valve 14 is connected to the intake manifold 11 behind the throttle valve 12 through a pipeline, the other end of the electromagnetic valve 14 is connected to the vacuum air storage tank 15 through a pipeline, the electromagnetic valve 14 is connected to the vehicle control unit 133 through a wire harness, the vehicle control unit 133 controls the opening and closing of the electromagnetic valve 14, when the electromagnetic valve 14 is opened, the vacuum air storage tank 15 is communicated with the intake manifold 11, and when the electromagnetic valve 14 is closed, the vacuum air storage tank 15 is disconnected with the intake manifold 11; the first pressure sensor 17 is connected to the engine controller 131 and is used for collecting an ambient atmospheric pressure value; the third pressure sensor 151 is mounted on the vacuum air storage tank 15, connected to the vehicle controller 133 through a wire harness, and used by the vehicle controller 133 to collect air pressure in the vacuum air storage tank 15; the engine controller 131 is connected with the vehicle controller 133 through a CAN bus 132, the engine controller 131 sends an engine crankshaft rotation speed signal, an intake manifold pressure signal, a throttle opening degree signal and an atmospheric pressure signal to the vehicle controller 133 through CAN communication, and the vehicle controller 133 sends an engine oil injection enabling signal and an engine torque request signal to the engine controller 131 through CAN communication; the vacuumizing unit 16 and the one-way valve 18 are connected to the vacuum air storage tank 15 through pipelines, the one-way valve 18 ensures that air can only flow from the vacuum air storage tank 15 to the vacuumizing unit 16, but air is not allowed to flow from the vacuumizing unit 16 to the vacuum air storage tank 15, the vacuumizing unit 16 is connected to the vehicle control unit 133 through a wire harness, and the vacuumizing unit 16 operates after the vehicle control unit 133 sends an opening instruction to pump air in the vacuum air storage tank 15 so as to reduce the pressure in the vacuum air storage tank 15.
The pressure sensors employed in the present embodiment may be, but are not limited to, gauge pressure sensors, differential pressure sensors, and absolute pressure sensors.
Further, as shown in fig. 2, a turbocharger 20 and a three-way catalyst 21 are provided in this order on the exhaust manifold of the engine 1. By arranging the turbocharger 20, the power of the engine is improved, and by additionally arranging the three-way catalyst 21, the tail gas of the engine 1 is purified, so that air pollution is avoided.
In order to ensure that a suitable vacuum degree is established in the vacuum air storage tank 15 to meet the engine start-up requirement, the present embodiment provides a control method of a start-up auxiliary system, and details of the present embodiment are described in detail below with reference to fig. 2 and 3.
As shown in fig. 3, the control method of the start-up assist system includes the steps of:
s1, when the engine 1 enters a stop state, the control unit 13 sends out a fuel cut-off instruction, and the throttle valve 12 is completely closed; specifically, when the fuel injection enable signal sent by the vehicle controller 133 to the engine controller 131 is set to 0 (the fuel injection enable signal is set to 1 indicates the fuel injection command, and the fuel injection enable signal is set to 0 indicates the fuel cut command), the engine controller 131 completely closes the throttle valve 12 after receiving the fuel cut command sent by the vehicle controller 133. After the throttle valve 12 is closed, the air pressure in the intake manifold 11 will drop dramatically and be much less than ambient atmospheric pressure, since the engine 1 is still rotating and the pistons are still drawing air from the intake manifold 11. When the vehicle controller 133 determines that the throttle valve 12 has been completely closed based on the received throttle opening signal, the pressure reduction control of the vacuum air tank 15 is performed, and the pressure reduction control marks position 1;
s2, judging whether the pressure in the air inlet manifold 11 is smaller than the pressure in the vacuum air storage tank 15 or not; if yes, the electromagnetic valve 14 is opened, and the vacuum air storage tank 15 is communicated with the air inlet manifold 11; specifically, in the case of the vacuum reservoir 15 decompression flag position 1, if the internal pressure of the intake manifold 11 of the engine 1 is lower than the air pressure of the vacuum reservoir 15, the solenoid valve 14 is opened, the vacuum reservoir 15 communicates with the intake manifold 11, and since the pressure in the intake manifold 11 is lower, the air in the vacuum reservoir 15 is drawn into the intake manifold 11, and the air pressure in the vacuum reservoir 15 is also sharply reduced and gradually kept the same as the air pressure in the intake manifold 11;
s3, when the preset working condition is met, immediately closing the electromagnetic valve 14;
s4, judging whether the pressure in the vacuum air storage tank 15 is larger than the maximum allowable pressure value;
and S5, if yes, starting the vacuumizing unit 16 until the pressure in the vacuum air storage tank 15 is smaller than the maximum allowable pressure value.
In short, when the engine 1 enters a stop state, the control unit 13 issues a fuel cut command, the throttle valve 12 is fully closed, and since the engine 1 is still rotating and the piston is still drawing air from the intake manifold 11, the air pressure in the intake manifold 11 will drop sharply and be much lower than the ambient atmospheric pressure; judging whether the pressure in the intake manifold 11 is smaller than the pressure in the vacuum air storage tank 15; if yes, the electromagnetic valve 14 is opened, so that the vacuum air storage tank 15 is communicated with the air inlet manifold 11, air in the vacuum air storage tank 15 is pumped into the air inlet manifold 11, and the pressure in the vacuum air storage tank 15 is also sharply reduced and gradually kept the same as the air pressure in the air inlet manifold 11; closing the solenoid valve 14 when a preset condition is satisfied; under the condition that the electromagnetic valve 14 is closed, judging whether the pressure in the vacuum air storage tank 15 is larger than the maximum allowable pressure value; if yes, the vacuumizing unit 16 is started until the pressure in the vacuum air storage tank 15 is smaller than the maximum allowable pressure value, so that proper vacuum degree is ensured to be established in the vacuum air storage tank 15, and the engine 11 is ensured to be started smoothly. Furthermore, the vacuum degree is established by firstly selecting the energy of the engine 1 when the engine is stopped, and then the vacuum degree is established by selecting the vacuum-pumping unit 16, so that the energy consumption is reduced.
Further, as shown in fig. 4, in step S3, the preset working condition is that the pressure in the vacuum air storage tank 15 is smaller than the maximum allowable pressure value; or the rotating speed of the engine 1 is lower than the sum of the upper limit rotating speed and the error rotating speed of the low-speed resonance region of the engine 1; or the pressure in the vacuum reservoir 15 is greater than the maximum allowable pressure value and the pressure in the intake manifold 11 begins to rise, as long as one of them is met, the solenoid valve 14 is immediately closed. In the present exemplary embodiment, the error rotational speed is 100 revolutions per minute.
Further, as shown in fig. 2, in the present embodiment, the vacuum pumping unit 16 is an electric vacuum pump, and the electric vacuum pump is electrically connected to the control unit 13, and the electric vacuum pump is not allowed to be turned on with the electromagnetic valve 14 kept open. The vacuum air storage tank 15 can be communicated with the air inlet manifold 11 only after the electromagnetic valve 14 is opened, and the energy in the shutdown process is utilized to assist the vacuum air storage tank 15 to build the vacuum degree, or the vacuum degree can be built only through the vacuumizing unit 16. In other embodiments, the vacuum unit 16 may also use other devices to evacuate the vacuum reservoir 15.
Further, in step S5, when the performance degradation of the electric vacuum pump is detected, the engine deceleration rate at the time of the stop is reduced and the engine deceleration time is prolonged. By reducing the deceleration rate of the engine during the shutdown, the deceleration time of the engine is prolonged, and the air suction time of the engine to the intake manifold 11 during the shutdown process is further prolonged, so that the pressure in the vacuum air storage tank 15 is reduced as much as possible.
Furthermore, in other embodiments, an auxiliary rotating mechanism may be disposed near the electric vacuum pump, and when the performance degradation of the electric vacuum pump is detected, the auxiliary rotating mechanism is in transmission connection with the electric vacuum pump, and the auxiliary rotating mechanism drives the electric vacuum pump to operate. When detecting that electric vacuum pump performance is normal, when not attenuating, supplementary slewing mechanism keeps disconnected connection with electric vacuum pump, and electric vacuum pump can normally extract air to vacuum gas holder 15.
Further, the generator 2 is used to drive the engine 1 to reduce the deceleration rate of the engine 1 at the stop. Specifically, the generator 2 outputs a certain torque to drag the engine 1, thereby achieving the slowing of the engine down speed.
Further, in step S5, if the pressure in the vacuum air tank 15 does not reach a value less than the maximum allowable pressure value within the set time, it is determined that the performance of the electric vacuum pump is degraded.
Further, the set time is the time required for the electric vacuum pump to reduce the initial pressure of the vacuum air storage tank 15 to the maximum allowable pressure value of the vacuum air storage tank 15, and then multiplied by 1.3 times. Specifically, this set time is obtained through experiments, and the time required for the electric vacuum pump to reduce the pressure of the vacuum air tank 15 to the maximum allowable pressure value of the vacuum air tank 15 is recorded at different initial pressures of the vacuum air tank 15, and this time is multiplied by 1.3 times as the vacuum pump performance decay determination time.
Further, during the shutdown, the initial pressure of the vacuum air tank 15 is the pressure at the instant when the solenoid valve 14 is closed and the electric vacuum pump is turned on in step S5.
Specifically, at the moment when the electromagnetic valve 14 is closed and the electric vacuum pump is opened, the pressure of the vacuum air storage tank 15 at this time is recorded as the initial pressure for opening the electric vacuum pump, if the electric vacuum pump fails to draw down the air pressure of the vacuum air storage tank 15 by air suction within a set time to be below the maximum allowable pressure, it is considered that the performance of the electric vacuum pump is degraded, the air pressure of the vacuum air storage tank 15 is reduced as much as possible by the vacuum of the intake manifold 11 of the engine 1 by slowing down the speed reduction rate after the oil of the engine is cut off, until after the pressure of the vacuum air storage tank 15 is smaller than the maximum allowable pressure value of the vacuum air storage tank 15, the electromagnetic valve 14 is closed, and the engine is normally stopped.
In the starting process, when the vehicle control unit 133 outputs positive torque to the generator 2, the generator 2 drags the engine 1 to start, the vehicle control unit 133 sends an oil cut instruction to the engine controller 131, and the engine controller 131 controls the throttle valve 12 to be completely closed according to the signal; if the air pressure in the vacuum air storage tank 15 is lower than the maximum allowable pressure of the vacuum air storage tank 15 when the vehicle controller 133 drags the engine 1, the NVH performance in the starting process is ensured by auxiliary air extraction of the vacuum air storage tank 15; when the engine 1 rotates at a speed greater than a certain speed (preferably, 20 to 50 revolutions), the vehicle controller 133 opens the solenoid valve 14, the vacuum air tank 15 communicates with the intake manifold 11, and because the air pressure in the vacuum air tank 15 is low, a portion of air in the intake manifold 11 is pumped into the vacuum air tank 15, the air pressure in the intake manifold 11 is rapidly reduced under the suction action of the piston and the suction action of the vacuum air tank 15, at this time, the amount of air compressed by the piston each time is reduced, and the compression reaction force of the piston is reduced.
During the starting process, after the rotation speed of the engine 11 exceeds 1000 revolutions or the vehicle controller 133 sends a fuel injection command to the engine controller 131, the vehicle controller 133 controls the electromagnetic valve 14 to close.
The method for calculating the maximum allowable pressure threshold value of the vacuum air storage tank 15 comprises the following steps: the maximum allowable pressure threshold value of the vacuum air storage tank 15 is obtained by looking up the atmospheric pressure value. The table output value is obtained through a test, the test method is that under the current atmospheric pressure, the pressure of the vacuum air storage tank 15 is reduced from large to small in sequence, the maximum value is the current atmospheric pressure value, the step length is reduced by 50hPa each time, then a start-up test is carried out, and the maximum vacuum air storage tank 15 pressure value which can be accepted by the start-up NVH is used as the table output value under the current atmospheric pressure; and repeating the tests under different atmospheric pressure values to finally obtain the maximum allowable 15 pressure value of the vacuum air storage tank under different atmospheric pressure values, wherein the maximum allowable 15 pressure value of the starting NVH performance can be ensured.
Regarding the setting of the volume of the vacuum gas container 15. In the embodiment, the air in the intake manifold 11 is extracted by the vacuum air tank 15 during the start-up process, and meanwhile, during the start-up process, the vacuum air tank 15 also extracts a part of air in the cylinder due to the opening of the throttle valve 12 of the engine 1, so that the volume of the vacuum air tank 15 is related to the volume of the intake manifold at the rear section of the throttle valve 12 and the displacement of the engine, and the volume of the intake manifold at the rear section plus the displacement of the engine is multiplied by 2 to be used as the volume of the vacuum air tank 15.
The solenoid valve 14 and the connecting line have a cross-sectional flow area. In this embodiment, during the start-up process, after the solenoid valve 14 is opened, the air in the intake manifold 11 needs to be quickly pumped into the vacuum air tank 15, so that the flow cross-sectional area of the solenoid valve 14 and the connecting pipeline needs to be selected appropriately. Specifically, the pressure of one end of the solenoid valve 14 is set to 300hPa on the premise that the volume of the vacuum gas tank 15 is determined, and after the solenoid valve 14 is opened, the pressure of the vacuum gas tank 15 should be pumped from 1000hPa to 300hPa within 0.4 seconds, and the minimum pipe cross-sectional area satisfying the pumping speed is used as the flow cross-sectional area value of the solenoid valve 14 and the connecting pipe.
The method for selecting the pumping speed (the capacity of the electric vacuum pump) of the electric vacuum pump is that when the initial pressure of the vacuum air storage tank 15 is atmospheric pressure, the electric vacuum pump is started, and the pressure of the vacuum air storage tank 15 can be reduced from the atmospheric pressure to the maximum allowable pressure of the vacuum air storage tank 15 within a time not more than 2 seconds.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A control method of a starting auxiliary system is characterized by comprising the following steps:
s1, the engine (1) enters a stop state, the control unit (13) sends out a fuel cut-off instruction, and the throttle valve (12) is completely closed;
s2, judging whether the pressure in the air inlet manifold (11) is smaller than the pressure in the vacuum air storage tank (15) or not; if yes, opening an electromagnetic valve (14) to enable the vacuum air storage tank (15) to be communicated with the air inlet manifold (11);
s3, immediately closing the electromagnetic valve (14) when a preset working condition is met;
s4, judging whether the pressure in the vacuum air storage tank (15) is larger than the maximum allowable pressure value or not;
and S5, if yes, starting the vacuumizing unit (16) until the pressure in the vacuum air storage tank (15) is smaller than the maximum allowable pressure value.
2. The control method of the lift assist system according to claim 1, wherein in the step S3, the preset operating condition is that the pressure in the vacuum air storage tank (15) is less than a maximum allowable pressure value; or
The rotating speed of the engine (1) is lower than the sum of the upper limit rotating speed and the error rotating speed of the low-speed resonance region of the engine (1); or
The pressure in the vacuum reservoir (15) is greater than the maximum allowable pressure value and the pressure in the intake manifold (11) begins to rise.
3. A control method of a start-up assistance system according to claim 2, characterized in that the evacuation unit (16) is an electric vacuum pump which is electrically connected to the control unit (13) and which is not allowed to be turned on with the solenoid valve (14) remaining open.
4. The control method of the startup assistance system according to claim 3, wherein in step S5, when the performance degradation of the electric vacuum pump is detected, the deceleration rate of the engine at the time of the shutdown is reduced, and the engine deceleration time is extended.
5. A control method of a start-up assisting system according to claim 4, characterized in that the deceleration rate of the engine (1) at the time of stop is reduced by using a manner that a generator (2) drags the engine (1) to operate.
6. The control method of the lift assist system according to claim 4, wherein in the step S5, if the pressure in the vacuum air tank (15) does not reach less than a maximum allowable pressure value within a set time, it is determined that the performance of the electric vacuum pump is degraded.
7. The control method of the startup assistance system according to claim 6, characterized in that the set time is 1.3 times the time required for the electric vacuum pump to reduce the vacuum air tank (15) from an initial pressure to a maximum allowable pressure value of the vacuum air tank (15).
8. The control method of the lift assist system according to claim 7, wherein the initial pressure of the vacuum air tank (15) is a pressure at the instant when the solenoid valve (14) is closed and the electric vacuum pump is turned on in the step S5.
9. A start-up assist system comprising an engine (1), an intake manifold (11), a throttle valve (12), a second pressure sensor (111), a vacuum reservoir (15), a third pressure sensor (151), a solenoid valve (14), a vacuum pumping unit (16) and a control unit (13), characterized in that the vacuum reservoir (15) is evacuated by a control method of the start-up assist system according to any one of claims 1 to 8.
10. The lift assist system of claim 9 further comprising a one-way valve (18), an inlet of the one-way valve (18) being in communication with the vacuum reservoir (15), an outlet of the one-way valve (18) being in communication with the evacuation unit (16).
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| WO2023082845A1 (en) * | 2021-11-15 | 2023-05-19 | 中国第一汽车股份有限公司 | Starting system and control method |
| CN116378838A (en) * | 2023-04-06 | 2023-07-04 | 重庆赛力斯新能源汽车设计院有限公司 | Shutdown control method and system for configuring range extender of high compression ratio engine |
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| CN113389645A (en) * | 2021-07-20 | 2021-09-14 | 中国第一汽车股份有限公司 | Hybrid electric vehicle and control method for eliminating start-up jitter |
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| CN107264502A (en) * | 2017-06-21 | 2017-10-20 | 南京世界村汽车动力有限公司 | Vacuum-control(led) system needed for automobile brake |
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| WO2023082845A1 (en) * | 2021-11-15 | 2023-05-19 | 中国第一汽车股份有限公司 | Starting system and control method |
| CN116378838A (en) * | 2023-04-06 | 2023-07-04 | 重庆赛力斯新能源汽车设计院有限公司 | Shutdown control method and system for configuring range extender of high compression ratio engine |
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