CN108386281B - System and method for estimating residual exhaust gas of internal combustion engine system - Google Patents

System and method for estimating residual exhaust gas of internal combustion engine system Download PDF

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CN108386281B
CN108386281B CN201810166380.4A CN201810166380A CN108386281B CN 108386281 B CN108386281 B CN 108386281B CN 201810166380 A CN201810166380 A CN 201810166380A CN 108386281 B CN108386281 B CN 108386281B
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exhaust
exhaust gas
pressure
internal combustion
combustion engine
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CN108386281A (en
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王魏
于洪涛
孙志超
刘少飞
尚鑫
宫雨
张艳青
贺燕铭
李斌
黄文炳
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BAIC Motor Powertrain Co Ltd
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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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B77/00—Component parts, details or accessories, not otherwise provided for
    • F02B77/08—Safety, indicating, or supervising devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2820/00—Details on specific features characterising valve gear arrangements
    • F01L2820/04—Sensors
    • F01L2820/041—Camshafts position or phase sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2820/00—Details on specific features characterising valve gear arrangements
    • F01L2820/04—Sensors
    • F01L2820/042—Crankshafts position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0406—Intake manifold pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0414—Air temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/101—Engine speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/70—Input parameters for engine control said parameters being related to the vehicle exterior
    • F02D2200/703—Atmospheric pressure

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

A system and method for estimating residual exhaust gas of an internal combustion engine system includes upstream and downstream pressure sensors, a temperature sensor, intake and exhaust camshaft position sensors, and a crankshaft sensor. The method comprises the following steps: the electronic control unit corrects the air inlet temperature according to the temperature signal, then estimates the inflation coefficient of the internal combustion engine cylinder body by combining the environmental pressure signal acquired by the upstream pressure sensor and the pressure signal of the air inlet manifold acquired by the downstream pressure sensor, estimates the exhaust pressure by combining the relative fuel quantity, corrects and compensates the exhaust pressure according to the overlap angle of the air inlet and outlet valves and the rotating speed signal of the crankshaft, respectively estimates the resident exhaust gas pressure close to one side of the exhaust valve and the pressure of the scavenged exhaust gas, and then estimates the flow of the scavenged exhaust gas during scavenging or estimates the flow of the back-sucked exhaust gas. The invention can improve the calculation accuracy of the residual waste gas, reduce the generation of nitrogen oxides during the combustion of the cylinder body of the internal combustion engine and reduce the emission.

Description

System and method for estimating residual exhaust gas of internal combustion engine system
Technical Field
The invention relates to the technical field of vehicle control, in particular to a system and a method for estimating residual exhaust gas of an internal combustion engine system.
Background
The residual exhaust gas of the engine block is the mixture of combusted air and fuel remaining in the cylinder after combustion in an ignited gasoline internal combustion engine. The flow of residual exhaust gases has a significant impact on emissions, performance, combustion stability and volumetric efficiency. The existing system and the estimation method need to additionally install a pressure sensor on a cylinder head of the internal combustion engine, and respectively install a temperature sensor and a pressure sensor on an exhaust pipe, and the existing system and the estimation method are a strategy for estimating the temperature and the pressure of exhaust gas in a cylinder by directly using the exhaust temperature and the exhaust pressure, have the defect of inaccurate estimation, and particularly have the potential risk on the reliability of the system because the instantaneously calculated value is inaccurate at the opening, closing and overlapping moments of a valve.
Disclosure of Invention
Accordingly, the present invention provides a system and a method for estimating residual exhaust gas of an internal combustion engine system to improve the calculation accuracy of the residual exhaust gas.
In order to solve the technical problem, the invention provides an estimation system of residual exhaust gas of an internal combustion engine system, wherein the internal combustion engine system comprises an internal combustion engine cylinder and an electronic control unit, the internal combustion engine cylinder is communicated with a worm gear supercharging device through an air inlet valve, the worm gear supercharging device comprises an air inlet manifold, an electronic throttle valve is arranged in the air inlet manifold, the internal combustion engine cylinder is communicated with an exhaust device through an exhaust valve, and the estimation system comprises an upstream pressure sensor, is arranged at the upstream of the electronic throttle valve and is used for detecting an ambient pressure signal; a downstream pressure sensor, disposed downstream of the electronic throttle valve, for detecting a pressure signal of an intake manifold; the temperature sensor is arranged at the upstream of the electronic throttle valve and used for acquiring an air inlet temperature signal of the internal combustion engine cylinder; an intake camshaft position sensor for detecting a position signal of an intake camshaft of the internal combustion engine block; an exhaust camshaft position sensor for detecting a position signal of an exhaust camshaft of the internal combustion engine block; a crankshaft sensor for detecting a rotational speed signal of a crankshaft of the internal combustion engine block; and the electronic control unit is used for estimating residual exhaust gas of the internal combustion engine system according to the ambient pressure signal, the pressure signal of the intake manifold, the intake temperature signal, the position signal of the intake camshaft, the position signal of the exhaust camshaft and the rotating speed signal of the crankshaft.
Further, the present invention provides the system for estimating residual exhaust gas of an internal combustion engine system, wherein the upstream pressure sensor and the temperature sensor are integrated temperature and pressure sensors.
In order to solve the above technical problem, the present invention further provides a method for estimating residual exhaust gas of an internal combustion engine system, which adopts the above estimation system for residual exhaust gas of an internal combustion engine system, and comprises the following steps:
the method comprises the following steps that firstly, an electronic control unit obtains an air inlet temperature signal of an internal combustion engine cylinder body collected by a temperature sensor, and estimates an air inlet manifold, an electronic throttle valve, an air inlet valve and temperature signals on two sides of the air inlet valve in the air flowing direction according to the air inlet temperature signal;
secondly, the electronic control unit estimates the inflation coefficient of fresh air in the cylinder body of the internal combustion engine according to the environment pressure signal acquired by the upstream pressure sensor, the pressure signal of the air inlet manifold acquired by the downstream pressure sensor and the temperature signals at the two sides of the air inlet valve;
estimating the exhaust pressure of the internal combustion engine system through the inflation coefficient, the relative fuel quantity, the ambient pressure signal and the pressure signal of the intake manifold according to the mass conservation law, wherein the exhaust pressure is the exhaust pressure on the side far away from the exhaust valve;
correcting and compensating the exhaust pressure according to the overlap angle of the intake valve and the exhaust valve and the rotating speed signal of the crankshaft, and respectively estimating the residual exhaust pressure close to one side of the exhaust valve and the scavenging exhaust pressure close to one side of the exhaust valve;
estimating the flow of the swept exhaust gas during scavenging or estimating the flow of the back-suction exhaust gas according to the following ideal gas equation formula;
Figure GDA0003056334830000021
in the above-mentioned formula,
Figure GDA0003056334830000031
Figure GDA0003056334830000032
Figure GDA0003056334830000033
Figure GDA0003056334830000034
wherein,
Figure GDA0003056334830000035
for sucking back the air mass flow of the residual exhaust gas or sweeping out the air mass flow of the residual exhaust gas,
Figure GDA0003056334830000036
for sucking back or sweeping out the maximum air mass flow, P, of the residual exhaust gas1Is a pressure signal upstream of the exhaust valve, P2Is a pressure signal downstream of the exhaust valve, P2/P1Is the pressure ratio of both sides of the exhaust valve, alpha is the overlap angle of the intake and exhaust valves, K is the isentropic index, T0Is absolute zero, T is the exhaust estimated temperature of the exhaust valve, P0Is standard atmospheric pressure, f1、f2、f3、f4Is a constructor.
Further, the present invention provides a method for estimating residual exhaust gas of an internal combustion engine system, further comprising the steps of:
estimating the temperature of the resident exhaust gas or the temperature of the returned exhaust gas according to the following formula;
TRsdl＝TExhGs×h((p22/p11)g(K))×f(p22/p11)，
when calculating the recirculated exhaust gas temperature, in the above formula,
Figure GDA0003056334830000041
f(p22/p11)＝1，
when calculating the resident exhaust gas temperature, in the above formula,
Figure GDA0003056334830000042
Figure GDA0003056334830000043
wherein, TRsdlFor the temperature of the resident exhaust gas or the temperature of the recirculated exhaust gas, TExhGsIs the exhaust temperature, K is an isentropic index, h, f, g are the constructors, P11Is a pressure signal upstream of the inlet valve 13, P22Is a pressure signal downstream of the inlet valve 13, P22/P11For the pressure ratio, alpha, upstream and downstream of the inlet valve 1311Is the closing angle of the exhaust valve, alpha12Opening angle of inlet valve, V (alpha)11) V (alpha) corresponding to the cylinder volume at the time of closing of the exhaust valve22) Is the cylinder volume at which the intake valve is open.
Further, the present invention provides a method for estimating residual exhaust gas of an internal combustion engine system, further comprising the steps of:
and step seven, further comprising the step of respectively estimating the flow rate of the resident exhaust gas and the flow rate of the returned exhaust gas under the condition of the overlap angle of the intake valve and the exhaust valve or not according to the deformation formula of the following ideal gas equation:
Figure GDA0003056334830000044
in the above-mentioned formula,
Figure GDA0003056334830000051
Figure GDA0003056334830000052
wherein, VRsdlFor the flow of the resident exhaust gas and the flow of the recirculated exhaust gas, PRsdlResidual exhaust gas pressure, T, for the current environmentRsdlFor the temperature of the resident exhaust gas or the temperature of the recirculated exhaust gas, TRsdlIs the temperature in Kelvin, T0Is absolute zero, P0Is at standard atmospheric pressure, PIntkIs the pressure of the intake manifold, PExhGsIs the exhaust pressure, α11Is the closing angle of the exhaust valve, alpha12Opening angle of inlet valve, VhIs the displacement of cylinder, epsilon is the compression ratio, gamma is half of the crankshaft rotation radius, i.e. stroke, l is the length of connecting rod, pi is the circumference ratio, alpha1The opening angle of the intake valve is set when the overlap angle exists, otherwise, the closing angle of the exhaust valve is set,
Figure GDA0003056334830000053
is alpha1As a function of (c).
Further, the present invention provides a method for estimating residual exhaust gas of an internal combustion engine system, further comprising the steps of:
and step eight, estimating a resident exhaust gas coefficient, a backflow exhaust gas coefficient, a suck-back exhaust gas coefficient or a scavenging exhaust gas coefficient according to the pumping process of the cylinder body of the internal combustion engine.
Further, the present invention provides the method for estimating residual exhaust gas of an internal combustion engine system, further comprising the step of calculating the overlap angle of intake and exhaust valves in the fourth step based on a difference between a position signal of an intake camshaft detected by an intake camshaft position sensor and a position signal of an exhaust camshaft detected by an exhaust camshaft position sensor.
Further, the present invention provides a method for estimating residual exhaust gas of an internal combustion engine system, wherein in the second step, the air charge coefficient in the cylinder of the internal combustion engine is estimated by using the following formula,
Figure GDA0003056334830000054
wherein, PIntkIs the pressure of the intake manifold, VIntkVe-bth is the air ratio before flow through the electronic throttle, V, for intake manifold volumeeEng _ spd is the rotational speed signal of the crankshaft, TIntkIs the temperature of the air in the intake manifold, T0Is absolute temperature, VhhIs the displacement of the cylinder, P0Is at standard atmospheric pressure.
Further, the present invention provides a method for estimating residual exhaust gas of an internal combustion engine system, wherein in the second step, the air charge coefficient in the cylinder of the internal combustion engine is estimated by using the following formula,
Figure GDA0003056334830000061
wherein, VeIs the coefficient of charge, P, within the cylinder of an internal combustion engineIntkIs the pressure of the intake manifold, TIntkIs the temperature of air in the intake manifold, T0Is absolute temperature, P0Is a standard atmospheric pressure, alpha1The closing angle of the exhaust valve is set,
Figure GDA0003056334830000062
as a function of the closing angle of the exhaust valve.
The technical scheme of the estimation system and the method for the residual exhaust gas of the internal combustion engine system has the following beneficial effects that: and the electronic control unit estimates the flow rate, the pressure and the temperature of residual exhaust gas of the internal combustion engine system and the coefficient of the residual exhaust gas according to an environment pressure signal detected by the upstream pressure sensor, a pressure signal of an intake manifold detected by the downstream sensor, an intake temperature signal detected by the temperature sensor, a position signal of an intake camshaft detected by the intake camshaft sensor, a position signal of an exhaust camshaft detected by the exhaust camshaft sensor and a rotation speed signal of a crankshaft. The invention can improve the calculation accuracy of the temperature and the flow of the residual exhaust gas of the internal combustion engine cylinder body. Because of the accurate calculation of the residual waste gas, the combustion efficiency of the internal combustion engine is improved, the generation of nitrogen oxides during the combustion of the cylinder body of the internal combustion engine is effectively controlled, the emission is reduced, and the control precision of an engine control system is further improved.
Drawings
FIG. 1 is a system for estimating residual exhaust gases of an internal combustion engine system;
FIG. 2 is a method of estimating residual exhaust gases of an internal combustion engine system;
FIG. 3 is a resident exhaust pressure correction factor;
FIG. 4 is a sweep exhaust pressure correction factor.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.
Example one
Referring to fig. 1, the present embodiment provides a residual exhaust gas estimation system based on an internal combustion engine system with a turbo charger, which includes an internal combustion engine body 10 and an electronic control unit 20, a turbo charger 30 communicating with the internal combustion engine body 10 through an intake valve 11, and an exhaust device 40 communicating with the internal combustion engine body 10 through an exhaust valve 12. Wherein the exhaust means 40 comprises an exhaust manifold 41, and a catalyst 42 disposed at the exhaust manifold 41 and remote from the exhaust valve 12. The turbocharger device 30 includes an intake manifold 35, an electronic throttle valve 31. The electronic throttle valve 31 is provided IN the intake manifold 35, and the gas enters the engine block 10 through the intake manifold 35 and the electronic throttle valve 31 and the intake valve 11 therein, passes through the intake manifold 35 and the electronic throttle valve 31 therein, and is discharged after passing through the exhaust valve 12, the exhaust manifold 41, and the catalyst 42, and the gas entering direction of the turbocharger 30, as indicated by an arrow IN, and the gas discharging direction of the exhaust device 40, as indicated by an arrow OUT.
Referring to fig. 1, the first embodiment provides a residual exhaust gas estimation system for an internal combustion engine system, including an upstream pressure sensor 33 and a temperature sensor 32 disposed upstream of an electronic throttle valve 31; wherein the upstream pressure sensor 33 is used for detecting an ambient pressure signal, and the temperature sensor 32 is used for detecting a pressure signal of an intake manifold 35; a downstream pressure sensor 34 provided downstream of the electronic throttle valve 31, the downstream pressure sensor 34 being configured to detect a pressure signal of an intake manifold 35, and further including an intake camshaft position sensor 13 configured to detect a position signal of an intake camshaft of the internal combustion engine block; an exhaust camshaft position sensor 14 for detecting a position signal of an exhaust camshaft of the internal combustion engine block; and a crankshaft sensor 15 for detecting a rotational speed signal of the crankshaft, wherein the electronic control unit 20 estimates residual exhaust gas of the internal combustion engine system based on the ambient pressure signal, the pressure signal of the intake manifold, the intake temperature signal, the position signal of the intake camshaft, the position signal of the exhaust camshaft, and the rotational speed signal of the crankshaft. The electronic control unit 20 is also used to control the opening or closing and the opening angle of the electronic throttle valve 31, the intake valve 11, and the exhaust valve 12. The electronic control unit 20 of the estimation system of the present embodiment is shared with the internal combustion engine system, and may be replaced with a separate controller.
In the first embodiment, the upstream pressure sensor 33 and the temperature sensor 32 located upstream of the electronic throttle valve 31 may be temperature and pressure sensors integrated into a whole. The number of sensors is reduced, and the structure of the estimation system is simplified. Of course, separate upstream pressure sensors 33 and temperature sensors 32 may also be used.
Example two
Referring to fig. 2, a second embodiment of the present invention provides a method for estimating residual exhaust gas of an internal combustion engine system, which is based on the system for estimating residual exhaust gas of an internal combustion engine system of the first embodiment, and includes the following steps:
step one, an intake air temperature correction model in the internal combustion engine cylinder 10 is constructed. That is, the electronic control unit 20 acquires an intake air temperature signal of the internal combustion engine block 10 collected by the temperature sensor 32, and estimates the temperature signals of the electronic throttle valve 31, the intake manifold 35, the intake valve 13, and both sides of the intake valve 13 in the gas flow direction based on the intake air temperature signal.
And step two, constructing an air inlet model in the internal combustion engine cylinder body 10. That is, the electronic control unit 20 estimates the charge factor of the fresh air in the engine block 10 based on the ambient pressure signal collected by the upstream pressure sensor 33, the pressure signal of the intake manifold collected by the downstream pressure sensor 34, and the temperature signals on both sides of the intake valve 13.
And step three, constructing an exhaust pressure model. That is, the exhaust pressure is estimated from the charge coefficient, the relative fuel amount, the ambient pressure signal, and the pressure signal of the intake manifold according to the law of conservation of mass. The estimated exhaust pressure is the exhaust pressure on the side of the exhaust manifold 41 remote from the exhaust valve 12.
And step four, constructing an exhaust pressure correction model. That is, the exhaust pressure is corrected and compensated according to the overlap angle between the intake and exhaust valves and the rotational speed signal of the crankshaft, and the residual exhaust pressure near the exhaust valve 12 and the scavenging exhaust pressure near the exhaust valve 12 are respectively estimated. The exhaust pressure correction model is used for correcting and compensating the exhaust pressure, the estimated resident exhaust gas pressure and the estimated swept exhaust gas pressure are the exhaust gas pressure close to the exhaust valve 14, and the estimated values are more accurate and have higher precision because the obtained resident exhaust gas pressure and the swept exhaust gas pressure are closer to the internal combustion engine cylinder body 10.
The intake/exhaust valve overlap angle is calculated from the difference between the position signal of the intake camshaft detected by the intake camshaft position sensor 13 and the position signal of the exhaust camshaft detected by the exhaust camshaft position sensor 14. For example, the position signal detected by the exhaust camshaft position sensor 14 minus the position signal detected by the intake camshaft position sensor 13 is equal to the overlap angle.
And step five, constructing a residual exhaust gas flow estimation model. Estimating the flow of the swept exhaust gas during scavenging or estimating the flow of the back-suction exhaust gas according to the following ideal gas equation formula;
Figure GDA0003056334830000081
in the above-mentioned formula (1),
Figure GDA0003056334830000091
Figure GDA0003056334830000092
Figure GDA0003056334830000093
Figure GDA0003056334830000094
wherein,
Figure GDA0003056334830000095
for sucking back the air mass flow of the residual exhaust gas or sweeping out the air mass flow of the residual exhaust gas,
Figure GDA0003056334830000096
for sucking back or sweeping out the maximum air mass flow, P, of the residual exhaust gas1Is a pressure signal upstream of the exhaust valve, P2Is a pressure signal downstream of the exhaust valve, P2/P1Is the pressure ratio of both sides of the exhaust valve, alpha is the overlap angle of the intake and exhaust valves, K is the isentropic index, T0At absolute zero, T is the exhaust estimate of the exhaust valveCalculating the temperature, P0Standard atmospheric pressure, f1, f2, f3, f4Is a constructor.
When the waste gas is sucked back, the waste gas is sucked into the combustion chamber through the exhaust manifold via the exhaust valve, and when the waste gas is swept out, the waste gas is swept into the exhaust manifold via the exhaust valve from the combustion chamber.
And step six, constructing a residual exhaust gas temperature estimation model. Namely estimating the temperature of the resident exhaust gas or the temperature of the returned exhaust gas according to the following formula;
TRsdl＝TExhGs×h((p22/p11 g(K))×f(p12/p11) (6)，
when calculating the returned exhaust gas temperature, in the above formula (6),
Figure GDA0003056334830000101
f(p22/p11)＝1 (8)，
when the temperature of the resident exhaust gas is calculated, in the above formula (6),
Figure GDA0003056334830000102
Figure GDA0003056334830000103
wherein, TRsdlFor the temperature of the resident exhaust gas or the temperature of the recirculated exhaust gas, TExhGsIs the exhaust temperature, K is an isentropic index, h, f, g are the constructors, P11Is a pressure signal upstream of the inlet valve, P22Is a pressure signal downstream of the inlet valve, P22/P11For the pressure ratio, alpha, upstream and downstream of the inlet valve11Is the closing angle of the exhaust valve, alpha12Opening angle of inlet valve, V (alpha)11) V (alpha) corresponding to the cylinder volume at the time of closing of the exhaust valve22) Is the cylinder volume at the time of opening of the intake valve。
Step seven, in the construction of the residual exhaust gas flow estimation model, the method further comprises the step of respectively estimating the flow rate of the residual exhaust gas and the flow rate of the returned exhaust gas under the condition of the overlap angle of the intake valve and the exhaust valve or not according to the following deformation formula of an ideal gas equation:
Figure GDA0003056334830000104
in the above-mentioned formula (11),
Figure GDA0003056334830000111
Figure GDA0003056334830000112
wherein, VeFor the flow of the resident exhaust gas or of the recirculated exhaust gas, PRsdlResidual exhaust gas pressure, T, for the current environmentRsdlFor the temperature of the resident exhaust gas or the temperature of the recirculated exhaust gas, TRsdlIs the temperature in Kelvin, T0Is absolute temperature, P0Is at standard atmospheric pressure, PIntkIs a pressure signal of the intake manifold, PExhGsIs the exhaust pressure, α11Is the closing angle of the exhaust valve, alpha12Opening angle of inlet valve, VhIs the displacement of cylinder, epsilon is the compression ratio, gamma is half of the crankshaft rotation radius, i.e. stroke, l is the length of connecting rod, pi is the circumference ratio, alpha1The opening angle of the intake valve is set when the overlap angle exists, otherwise, the closing angle of the exhaust valve is set,
Figure GDA0003056334830000113
is alpha1As a function of (c).
In step seven, the transient state of the current resident or swept exhaust gas pressure when the exhaust valve is closed and the intake valve is opened is considered to be corrected, and the correction factor is p2/p1Can be used to determine the resident exhaust gas pressure in accordance with the experiment shown in FIG. 3Calibration and regression analysis was performed and the pressure of the scavenged exhaust gas was calibrated and regression analyzed according to the experimental approach in fig. 4.
And step eight, estimating a resident exhaust gas coefficient, a backflow exhaust gas coefficient, a suck-back exhaust gas coefficient or a scavenging exhaust gas coefficient according to the pumping process of the cylinder body of the internal combustion engine. For example, a residual exhaust gas flow coefficient and a residual exhaust gas pressure coefficient are estimated.
In the above steps, the exhaust temperature is estimated by an exhaust pressure correction model or detected by a temperature sensor provided in the exhaust apparatus 40.
The charge coefficient of the fresh air in the second step can be redundantly estimated by adopting the following two methods:
method one, manifold model equation (14),
Figure GDA0003056334830000114
wherein, PIntkIs the pressure of the intake manifold, VIntkVe-bth is the air ratio before flow through the electronic throttle, V, for intake manifold volumeeEng _ spd is the rotational speed signal of the crankshaft, TIntkIs the temperature of the air in the intake manifold, T0Is absolute zero degree, VhIs the displacement of the cylinder, P0Is at standard atmospheric pressure.
The second method, formula (15),
Figure GDA0003056334830000121
wherein, VeIs the coefficient of charge, P, within the cylinder of an internal combustion engineIntkIs the pressure of the intake manifold, TIntkIs the temperature of air in the intake manifold, T0Is absolute temperature, P0Is a standard atmospheric pressure, alpha1The closing angle of the exhaust valve is set,
Figure GDA0003056334830000122
for closure of exhaust valvesA function of the angle.
The method comprises the steps of respectively calculating the residual waste gas, the backflow waste gas, the suck-back waste gas and the flow of the swept-out waste gas during scavenging in the internal combustion engine cylinder body through a residual waste gas flow estimation model, correcting and compensating the temperature and the pressure of the waste gas which have larger influence in the calculation process, constructing a transient in-cylinder exhaust pressure correction model at the moment of the overlap angle of an intake valve and an exhaust valve, further estimating the temperature of the residual waste gas and the temperature of the backflow waste gas, extracting and calculating a residual waste gas coefficient and a backflow waste gas coefficient in the internal combustion engine cylinder body according to the residual waste gas flow estimation model, and accordingly improving the estimation accuracy of the residual waste gas in the internal combustion engine.
The method is characterized by estimating the pressure of the residual waste gas in the cylinder body of the internal combustion engine and the pressure of the scavenged waste gas, estimating the temperature of the residual waste gas in the cylinder and the temperature of the waste gas reflowing to an intake manifold, and respectively calculating the coefficient of the residual waste gas in the cylinder and the coefficient of the reflowing waste gas by using the estimated temperature as compensation.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the description and claims of the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (9)

1. A residual exhaust gas estimation method of an internal combustion engine system, characterized by comprising the steps of:
the method comprises the following steps that firstly, an electronic control unit obtains an air inlet temperature signal of an internal combustion engine cylinder body collected by a temperature sensor, and estimates an air inlet manifold, an electronic throttle valve, an air inlet valve and temperature signals on two sides of the air inlet valve in the air flowing direction according to the air inlet temperature signal;
secondly, the electronic control unit estimates the inflation coefficient of fresh air in the cylinder body of the internal combustion engine according to the environment pressure signal acquired by the upstream pressure sensor, the pressure signal of the air inlet manifold acquired by the downstream pressure sensor and the temperature signals at the two sides of the air inlet valve;
estimating the exhaust pressure of the internal combustion engine system through the inflation coefficient, the relative fuel quantity, the ambient pressure signal and the pressure signal of the intake manifold according to the mass conservation law, wherein the exhaust pressure is the exhaust pressure on the side far away from the exhaust valve;
correcting and compensating the exhaust pressure according to the overlap angle of the intake valve and the exhaust valve and the rotating speed signal of the crankshaft, and respectively estimating the residual exhaust pressure close to one side of the exhaust valve and the scavenging exhaust pressure close to one side of the exhaust valve;
estimating the flow of the swept exhaust gas during scavenging or estimating the flow of the back-suction exhaust gas according to the following ideal gas equation formula;
Figure FDA0003056334820000011
in the above-mentioned formula,
Figure FDA0003056334820000012
Figure FDA0003056334820000021
Figure FDA0003056334820000022
Figure FDA0003056334820000023
wherein,
Figure FDA0003056334820000024
for sucking back the air mass flow of the residual exhaust gas or sweeping out the air mass flow of the residual exhaust gas,
Figure FDA0003056334820000025
for sucking back or sweeping out the maximum air mass flow, P, of the residual exhaust gas1Is a pressure signal upstream of the exhaust valve, P2Is a pressure signal downstream of the exhaust valve, P2/P1Is the pressure ratio of both sides of the exhaust valve, alpha is the overlap angle of the intake and exhaust valves, K is the isentropic index, T0Is absolute zero, T is the exhaust estimated temperature of the exhaust valve, P0Is standard atmospheric pressure, f1、f2、f3、f4Is a constructor.
2. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 1, wherein said internal combustion engine system includes an engine block in communication with a turbocharger through an intake valve, said turbocharger including an intake manifold in which an electronic throttle valve is disposed, said engine block in communication with an exhaust through an exhaust valve, said estimation system comprising:
an upstream pressure sensor disposed upstream of the electronic throttle valve for detecting an ambient pressure signal;
a downstream pressure sensor, disposed downstream of the electronic throttle valve, for detecting a pressure signal of an intake manifold;
the temperature sensor is arranged at the upstream of the electronic throttle valve and used for acquiring an air inlet temperature signal of the internal combustion engine cylinder;
an intake camshaft position sensor for detecting a position signal of an intake camshaft of the internal combustion engine block;
an exhaust camshaft position sensor for detecting a position signal of an exhaust camshaft of the internal combustion engine block;
a crankshaft sensor for detecting a rotational speed signal of a crankshaft of the internal combustion engine block;
and the electronic control unit is used for estimating residual exhaust gas of the internal combustion engine system according to the ambient pressure signal, the pressure signal of the intake manifold, the intake temperature signal, the position signal of the intake camshaft, the position signal of the exhaust camshaft and the rotating speed signal of the crankshaft.
3. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 1, wherein the upstream pressure sensor and the temperature sensor are integrated temperature-pressure sensors.
4. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 1, characterized by further comprising the step of:
estimating the temperature of the resident exhaust gas or the temperature of the returned exhaust gas according to the following formula;
TRsdl＝TExhGs×h((p22/p11 g(K))×f(p12/p11)，
when calculating the recirculated exhaust gas temperature, in the above formula,
Figure FDA0003056334820000031
f(p22/p11)＝1，
when calculating the resident exhaust gas temperature, in the above formula,
Figure FDA0003056334820000032
Figure FDA0003056334820000033
wherein, TRsdlFor the temperature of the resident exhaust gas or the temperature of the recirculated exhaust gas, TExhGsIs the exhaust temperature, K is an isentropic index, h, f, g are the constructors, P11Is a pressure signal upstream of the inlet valve, P22Is a pressure signal downstream of the inlet valve, P22/P11For the pressure ratio, alpha, upstream and downstream of the inlet valve11Is the closing angle of the exhaust valve, alpha12Opening angle of inlet valve, V (alpha)11) V (alpha) corresponding to the cylinder volume at the time of closing of the exhaust valve22) Is the cylinder volume at which the intake valve is open.
5. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 4, characterized by further comprising the step of:
and step seven, further comprising the step of respectively estimating the flow rate of the resident exhaust gas and the flow rate of the returned exhaust gas under the condition of the overlap angle of the intake valve and the exhaust valve or not according to the deformation formula of the following ideal gas equation:
Figure FDA0003056334820000041
in the above-mentioned formula,
Figure FDA0003056334820000042
Figure FDA0003056334820000043
wherein, VRsdlFor the flow of the resident exhaust gas and the flow of the recirculated exhaust gas, PRsdlResidual exhaust gas pressure, T, for the current environmentRsdlFor the temperature of the resident exhaust gas or the temperature of the recirculated exhaust gas, TRsdlIs the temperature in Kelvin, T0Is absolute zero, P0Is at standard atmospheric pressure, PIntkIs the pressure of the intake manifold, PExhGsIs the exhaust pressure, α11Is the closing angle of the exhaust valve, alpha12Opening angle of inlet valve, VhIs the displacement of cylinder, epsilon is the compression ratio, gamma is half of the crankshaft rotation radius, i.e. stroke, l is the length of connecting rod, pi is the circumference ratio, alpha1The opening angle of the intake valve is set when the overlap angle exists, otherwise, the closing angle of the exhaust valve is set,
Figure FDA0003056334820000044
is alpha1As a function of (c).
6. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 5, characterized by further comprising the step of:
and step eight, estimating a resident exhaust gas coefficient, a backflow exhaust gas coefficient, a suck-back exhaust gas coefficient or a scavenging exhaust gas coefficient according to the pumping process of the cylinder body of the internal combustion engine.
7. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 1, further comprising the step of calculating the intake-exhaust valve overlap angle in the fourth step based on a difference between the position signal of the intake camshaft detected by the intake camshaft position sensor and the position signal of the exhaust camshaft detected by the exhaust camshaft position sensor.
8. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 1, wherein the charge coefficient of fresh air in the cylinder block of the internal combustion engine in the second step is estimated using the following formula,
Figure FDA0003056334820000051
wherein, PIntkIs the pressure of the intake manifold, VIntkVe-bth is the air ratio before flow through the electronic throttle, V, for intake manifold volumeeEng _ spd is the rotational speed signal of the crankshaft, TIntkIs the temperature of the air in the intake manifold, T0Is absolute zero degree, VhIs the displacement of the cylinder, P0Is at standard atmospheric pressure.
9. The method of estimating residual exhaust gas of an internal combustion engine system according to claim 1, wherein the coefficient of charge in the cylinder block of the internal combustion engine in the second step is estimated using the following formula,
Figure FDA0003056334820000052
wherein, VeIs the coefficient of charge, P, within the cylinder of an internal combustion engineIntkIs the pressure of the intake manifold, TIntkIs the temperature of air in the intake manifold, T0Is absolute zero, P0Is a standard atmospheric pressure, alpha1The closing angle of the exhaust valve is set,
Figure FDA0003056334820000053
as a function of the closing angle of the exhaust valve.
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