CN113343597B - Method and device for calculating virtual pressure behind throttle valve - Google Patents
Method and device for calculating virtual pressure behind throttle valve Download PDFInfo
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Abstract
The invention discloses a method and a device for calculating virtual pressure behind a throttle valve, which comprises the step of calculating steady-state pressure P of a nozzle inlet under a steady-state working condition 2 (t); calculating transient pressure delta P of nozzle inlet under transient working condition 2 (t + 1), calculating the virtual pressure P after the throttle 2 (t+1)＝P 2 (t)+ΔP 2 (t + 1). The invention calculates the steady state pressure P of the nozzle inlet under the steady state working condition 2 (t); and calculating the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1), the post-throttle virtual pressure P can be finally calculated 2 (t+1)＝P 2 (t)+ΔP 2 (t + 1) and the virtual pressure behind the throttle valve provides support for calculating the flow of the throttle valve and the flow of the spray pipe, so that the accuracy of the air inflow is improved, the control of the air-fuel ratio of the engine is facilitated, and the emission and the economical efficiency of the engine are improved.
Description
Technical Field
The invention relates to the technical field of gas engines, in particular to a method and a device for calculating virtual pressure behind a throttle valve.
Background
The gas engine controls the air quantity entering the engine through the throttle valve, and the corresponding natural gas is sprayed according to the calculated air inflow, so that the accurate control of the power and the air-fuel ratio of the engine is realized. The accuracy of the air quantity calculation directly affects the control of the air-fuel ratio, which directly affects the emissions and economy of the engine. In the prior art, the actual air inlet flow is mainly calculated through the opening of a throttle valve and the front-back pressure ratio. 1) Under the transient working condition, the pressure behind the throttle valve is subjected to more interference factors, so that the effective pressure of the flow is difficult to measure and calculate, and the accuracy of flow calculation is influenced. 2) When the opening of the throttle valve is large, the front-back pressure ratio is in a nonlinear area, and the calculation accuracy of the actual air inflow is poor.
Therefore, how to improve the accuracy of the intake air flow calculation is a technical problem that those skilled in the art have to solve.
Disclosure of Invention
The invention aims to provide a method for calculating a virtual pressure behind a throttle valve and a method and a device for calculating the virtual pressure behind the throttle valve, so that the accuracy of air inflow calculation is improved.
To achieve the above object, the present invention provides an apparatus for calculating a virtual pressure behind a throttle valve, comprising:
calculating the steady-state pressure P of the nozzle inlet under steady-state conditions 2 (t)；
Calculating transient pressure delta P of nozzle inlet under transient working condition 2 (t+1)；
Calculating a post-throttle virtual pressure P 2 (t+1)＝P 2 (t)+ΔP 2 (t+1)。
The invention also discloses a device for calculating the virtual pressure behind the throttle valve, which comprises the following components:
a first calculation unit for calculating the steady-state pressure P of the nozzle inlet under steady-state conditions 2 (t)；
A second calculation unit for calculating the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t+1)；
A third calculation unit for calculating the virtual pressure P behind the throttle valve 2 (t+1)＝P 2 (t)+ΔP 2 (t+1)。
The method for calculating the virtual pressure behind the throttle valve calculates the steady-state pressure P of the nozzle inlet under the steady-state working condition 2 (t); and calculating the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1), the post-throttle virtual pressure P can be finally calculated 2 (t+1)＝P 2 (t)+ΔP 2 (t + 1) and the virtual pressure behind the throttle valve provides support for calculating the flow of the throttle valve and the flow of the spray pipe, so that the accuracy of the air inflow is improved, the control of the air-fuel ratio of the engine is facilitated, and the emission and the economical efficiency of the engine are improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic structural diagram of an air intake venturi apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic flow chart illustrating a method for calculating a post-throttle virtual pressure according to an embodiment of the present invention;
FIG. 3 is a block diagram of an apparatus for calculating a virtual pressure behind a throttle valve according to an embodiment of the present invention;
FIG. 4 is a block diagram of a first computing unit according to an embodiment of the present invention;
FIG. 5 is a block diagram of a second computing unit according to an embodiment of the present invention;
fig. 6 is a block diagram of a mass calculation unit according to an embodiment of the present invention.
Wherein: 100 is a throttle valve, 200 is a spray pipe, 300 is a first calculation unit, 400 is a second calculation unit, 500 is a third calculation unit, 301 is a first pressure acquisition unit, 302 is a second pressure acquisition unit, 303 is a first processing unit, 401 is a temperature acquisition unit, 402 is a mass calculation unit, 403 is a second processing unit, 4021 is a first flow calculation unit, 4022 is a second flow calculation unit, and 4023 is a third processing unit.
Detailed Description
The core of the invention is to provide a method and a device for calculating the virtual pressure behind the throttle valve so as to improve the accuracy of calculating the air inflow.
The gas engine uses natural gas as raw material, and the air and gas are mixed and fed into cylinder to make combustion and produce work. Currently, the air intake system in a gas engine employs an intake venturi device that integrates the throttle valve 100 and the nozzle pipe 200 together as shown in fig. 1. During operation, air flows into the throttle valve 100 from the throttle inlet 101 and enters the nozzle inlet 201 through the throttle outlet 102, gas enters the nozzle 200 from the gas inlet 202 and is fully mixed with the air, and the mixed gas flows out from the nozzle outlet 203. The pressure P1 before the throttle valve, the temperature T1 before the throttle valve, the pressure P3 at the outlet of the spray pipe and the temperature T3 at the outlet of the spray pipe are obtained by arranging sensors. The core of the present invention is that the post-throttle virtual pressure P2 needs to be obtained by calculation.
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and embodiments.
Referring to fig. 2, a method for calculating a virtual pressure after a throttle according to the present invention includes:
s1, calculating steady-state pressure P of an inlet of a spray pipe under a steady-state working condition 2 (t)。
In steady-state operation, i.e. the amount of air flowing from the throttle into the nozzle and out of the nozzle at time t is equal, i.e. Q Thr (t)＝Q Noz (t) wherein Q Thr (t) is the throttle air quantity at time t, Q Noz And (t) is the air quantity of the spray pipe at the time t.
Wherein the inlet steady-state pressure P of the nozzle under steady-state conditions is calculated 2 The (t) is specifically:
acquiring the front pressure P of the throttle valve under the steady-state working condition 1 (t) the pressure is directly picked up by a sensor, or stored by the gas engine invoked.
Obtaining the pressure P of the outlet of the spray pipe under the steady state working condition 3 (t) the pressure is directly picked up by a sensor, or stored by the gas engine invoked.
Obtaining effective area A of throttle valve 1 The diameter size is recorded in the specification of the air intake venturi device at the time of shipment, and the effective area a can be directly calculated from the diameter size 1 The effective area A is set 1 And storing and directly calling when in use.
The steady-state pressure P of the nozzle inlet under steady-state conditions 2 (t) satisfies:
wherein the content of the first and second substances,
/>
psi is the ratio of the pressure behind the throttle valve to the pressure in front of the throttle valve under the steady-state working condition,
the unit is%;
beta is the diameter ratio, the ratio of the throat diameter to the inlet diameter of the Venturi tube;
d is the diameter of the throat, provided by the manufacturer, in m;
λ desired the required equivalence ratio is obtained by looking up a table according to the rotating speed.
S2, calculating transient pressure delta P of the nozzle inlet under the transient working condition 2 (t+1)。
When the transient working condition occurs, it can be understood that, at the time of t +1, the throttle valve is in front, the pressure in front of the throttle valve changes first, and then the flow passing through the throttle valve changes first. After the spray pipe is installed on the throttle valve, pressure conversion is relatively delayed, so that a certain deviation exists between the air quantity passing through the throttle valve and the air quantity passing through the spray pipe, the sum of total flow deviation in the transient state is obtained according to the flow deviation integration of the air quantity passing through the throttle valve and the air quantity passing through the spray pipe, and the pressure deviation in the current flow deviation, namely the transient pressure of the inlet of the spray pipe, is obtained according to an ideal gas equation PV = MRT.
The calculation of the transient pressure of the nozzle inlet under the transient working condition is specifically as follows:
(S21) acquiring the temperature T before the throttle valve under the transient working condition 1 (t + 1). The temperature value is acquired directly, or the temperature value is stored in the gas engine and is directly called when the gas engine is used.
(S22) calculating the mass deviation Delta m under the transient working condition.
The mass deviation Δ m under the transient working condition is calculated as follows:
(1) Calculating throttle flow Q under transient working condition Thr (t + 1); calculating throttle flow Q under transient working condition Thr (t + 1) specifically includes:
obtaining the temperature T before the throttle valve under the transient working condition 1 (t + 1); this temperature is either directly acquired by a sensor or stored by the gas engine called for.
Acquiring throttle front pressure P under transient working condition 1 (t + 1); this pressure is either directly sensed by the sensor or stored by the gas engine called for.
Throttle flow Q under transient conditions Thr (t + 1) satisfies:
(2) Calculating the air flow Q of the nozzle under steady-state conditions Air (t); calculating the air flow Q of the nozzle under the steady-state working condition Air The (t) is specifically:
calculating the flow Q of the mixed gas in the nozzle under the steady state working condition Noz (t); calculating the flow Q of the mixed gas in the spray pipe under the steady-state working condition Noz (t) satisfies:
where c is an outflow coefficient, a coefficient representing the relationship between the actual flow through the device and the theoretical flow, typically set to 1;
epsilon is the expansion coefficient, and a constant of 1 is set;
beta is the diameter ratio, the throat diameter and the inlet diameter ratio of the Venturi tube, and a manufacturer provides two sizes without units;
ΔP 1 (t) is the pressure difference, Δ P, between the nozzle inlet and the nozzle outlet under steady-state conditions 1 (t)＝P 2 (t)-P 3 (t), unit Pa;
rho is the average density under the steady state working condition, and the unit is kg/m 3 ，
T 1 And (t) is the temperature before the throttle valve under the steady-state working condition, in K, and the temperature is directly acquired through a sensor or stored by the called gas engine.
The flow rate Q of the air flowing through the nozzle in the steady-state operating condition Air (t) satisfies:
wherein λ is stoic Theoretical air-fuel gas with a constant of 16.7;
λ desired the required equivalence ratio is obtained by looking up a table according to the rotating speed.
(3) Then the mass deviation Δ m under transient conditions satisfies:
wherein, K P Is an integral coefficient and can be calibrated.
(S23) transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1) satisfies:
wherein V is the single cylinder displacement, in L;
r is the theoretical gas constant, 287J/(kg.K).
S3, calculating the virtual pressure P behind the throttle valve 2 (t+1)＝P 2 (t)+ΔP 2 (t+1)。
The method for calculating the virtual pressure behind the throttle valve calculates the steady-state pressure P of the nozzle inlet under the steady-state working condition 2 (t); and calculating the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1), the post-throttle virtual pressure P can be finally calculated 2 (t+1)＝P 2 (t)+ΔP 2 (t + 1) and the virtual pressure behind the throttle valve provides support for calculating the flow of the throttle valve and the flow of the spray pipe, so that the accuracy of the air inflow is improved, the control of the air-fuel ratio of the engine is facilitated, and the emission and the economical efficiency of the engine are improved.
As shown in fig. 3, the present invention also discloses an apparatus for calculating a virtual pressure behind a throttle, comprising:
a first calculation unit 300 for calculating a steady state pressure P of the nozzle inlet under steady state conditions 2 (t)；
A second calculation unit 400 for calculating a transient pressure Δ P of the nozzle inlet under transient conditions 2 (t+1)；
A third calculation unit 500 for calculating a post-throttle virtual pressure P 2 (t+1)＝P 2 (t)+ΔP 2 (t+1)。
The device for calculating the virtual pressure behind the throttle valve calculates the steady-state pressure P of the nozzle inlet under the steady-state working condition 2 (t); and calculating the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1), the post-throttle virtual pressure P can be finally calculated 2 (t+1)＝P 2 (t)+ΔP 2 (t + 1) and the virtual pressure behind the throttle valve provides support for calculating the flow of the throttle valve and the flow of the spray pipe, so that the accuracy of the air inflow is improved, the control of the air-fuel ratio of the engine is facilitated, and the emission and the economical efficiency of the engine are improved.
As shown in fig. 4, the first calculating unit 300 includes:
obtaining the front pressure P of the throttle valve under the steady-state working condition 1 (t) the first pressure collecting unit 301;
obtaining the pressure P of the outlet of the spray pipe under the steady state working condition 3 (t) a second pressure acquisition unit 302;
storing effective area A of throttle 1 The first memory cell of (1);
a first processing unit 303, wherein the first processing unit 303 calculates a steady-state pressure P of the nozzle inlet under a steady-state working condition 2 (t) satisfies:
wherein the content of the first and second substances,
psi is the ratio of the pressure behind the throttle valve to the pressure in front of the throttle valve under the steady-state working condition,
the unit is%;
beta is the diameter ratio, the ratio of the throat diameter to the inlet diameter of the Venturi tube;
d is the diameter of the throat, provided by the manufacturer, in m;
λ desired the required equivalence ratio is obtained by looking up a table according to the rotating speed.
As shown in fig. 5, the second calculation unit 400:
obtaining the temperature T before the throttle valve under the transient working condition 1 A temperature acquisition unit 401 of (t + 1);
a mass calculation unit 402 for calculating a mass deviation Δ m under a transient condition;
a second processing unit 403, wherein the second processing unit 403 calculates a transient pressure Δ P of the nozzle inlet under a transient condition 2 (t + 1) satisfies:
wherein V is the single cylinder displacement, in L;
r is the theoretical gas constant, 287J/(kg.K).
As shown in fig. 6, the quality calculation unit 402 includes:
calculating throttle flow Q under transient working condition Thr The first flow amount calculation unit 4021 of (t + 1);
calculating the air flow Q of the nozzle under steady-state conditions Air The second flow amount calculation unit 4022 of (t);
a third processing unit 4023, where the third processing unit 4023 calculates that the mass deviation Δ m under the transient operating condition satisfies:
wherein, K P Is an integral coefficient and can be calibrated.
The first flow amount calculation unit 4021 includes:
a fourth processing unit for calculating the throttle flow Q under the transient working condition Thr (t + 1) satisfies:
wherein the throttle front pressure P is determined in transient operating mode 1 (t + 1) is acquired by the first pressure acquisition unit 301.
The second flow amount calculation unit 4022 includes:
for calculating the flow Q of the mixture in the nozzle under steady-state conditions Noz (t) a third flow rate calculation unit;
a fifth processing unit to calculate the air flow Q through the nozzle under steady state conditions Air (t) satisfies:
wherein λ is stoic Theoretical air-fuel gas, constant 16.7;
λ desired the required equivalence ratio is obtained by looking up a table according to the rotating speed.
The above-mentionedThe third flow calculating unit calculates the flow Q of the mixed gas in the nozzle under the steady-state working condition Noz (t) satisfies:
where c is an outflow coefficient, a coefficient representing the relationship between the actual flow through the device and the theoretical flow, typically set to 1;
epsilon is an expandable coefficient and is set to be a constant 1;
beta is the diameter ratio, the ratio of the throat diameter to the inlet diameter of the Venturi tube, two sizes are provided by a manufacturer, and the unit is omitted by self calculation;
d is the diameter of the throat, provided by a manufacturer, and is in a unit of m;
ΔP 1 (t) is the pressure difference, Δ P, between the nozzle inlet and the nozzle outlet under steady-state conditions 1 (t)＝P 2 (t)-P 3 (t), unit Pa;
rho is the average density under the steady state working condition and the unit is kg/m 3 ，
T 1 (t) is the temperature before the throttle in steady state conditions, in K.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a component of' ...does not exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method of calculating a post-throttle virtual pressure, comprising:
calculating the steady-state pressure P of the nozzle inlet under steady-state conditions 2 (t); calculating the inlet steady-state pressure P of the spray pipe under the steady-state working condition 2 The (t) is specifically: acquiring the front pressure P of the throttle valve under the steady-state working condition 1 (t); obtaining the pressure P of the outlet of the spray pipe under the steady state working condition 3 (t); obtaining effective area A of throttle valve 1 (ii) a The steady-state pressure P of the nozzle inlet under steady-state conditions 2 (t) satisfies:
wherein +>
Psi is the ratio of the throttle back pressure to the throttle front pressure under the steady-state working condition, and is greater than or equal to>
The unit is%; beta is the diameter ratio, the ratio of the throat diameter to the inlet diameter of the Venturi tube; d is the diameter of the throat, provided by a manufacturer, and is in a unit of m; lambda desired Looking up a table according to the rotating speed to obtain the required equivalence ratio;
calculating transient pressure delta P of nozzle inlet under transient working condition 2 (t + 1); the calculation of the transient pressure of the nozzle inlet under the transient working condition is specifically as follows: obtaining the temperature T before the throttle valve under the transient working condition 1 (t + 1); calculating mass deviation delta m under the transient working condition; the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1) satisfies:
wherein V is single cylinder displacement, in units of L; r is theoretical gas constant, 287J/(kg.K);
calculating a virtual pressure P behind a throttle 2 (t+1)＝P 2 (t)+ΔP 2 (t+1。
2. The method according to claim 1, wherein the calculating of the mass deviation Δ m under transient conditions is specifically:
calculating throttle flow Q under transient working condition Thr (t+1)；
Calculating the air flow Q of the nozzle under steady-state conditions Air (t)；
Then the mass deviation Δ m under transient conditions satisfies:
wherein, K P Is an integral coefficient and can be calibrated.
3. The method of claim 2, wherein the calculating throttle flow Q during transient conditions Thr (t + 1) specifically includes:
obtaining the temperature T before the throttle valve under the transient working condition 1 (t+1)；
Acquiring the front pressure P of the throttle valve under the transient working condition 1 (t+1)；
Throttle flow Q under transient conditions Thr (t + 1) satisfies:
4. The method of claim 3, wherein the calculating the mass airflow Q of the nozzle under steady state conditions Air The (t) is specifically:
calculating the flow Q of the mixed gas in the nozzle under the steady state Noz (t)；
The air flow Q through the nozzle under steady state conditions Air (t) satisfies:
wherein λ is stoic Theoretical air-fuel gas with a constant of 16.7;
λ desired the required equivalence ratio is obtained by looking up a table according to the rotating speed.
5. The method of claim 4, wherein the calculating the amount of nozzle mixture flow Q at steady state operating conditions Noz (t) satisfies:
wherein c is an outflow coefficient, a coefficient representing the relationship between the actual flow rate and the theoretical flow rate through the device is set to 1;
epsilon is an expandable coefficient and is set to be a constant 1;
beta is the diameter ratio, the ratio of the throat diameter to the inlet diameter of the Venturi tube, and two sizes are provided by manufacturers without units;
ΔP 1 (t) is the pressure difference, Δ P, between the nozzle inlet and the nozzle outlet under steady-state conditions 1 (t)＝P 2 (t)-P 3 (t), unit Pa;
rho is the average density under the steady state working condition and the unit is kg/m 3 ，
T 1 (t) is the temperature before the throttle in steady state conditions, in K.
6. An apparatus for calculating a virtual pressure behind a throttle valve, comprising:
a first calculation unit for calculating the steady-state pressure P of the nozzle inlet under steady-state conditions 2 (t); the first calculation unit includes: acquiring the front pressure P of the throttle valve under the steady-state working condition 1 (t) a first pressure acquisition unit; obtaining the pressure P of the outlet of the spray pipe under the steady state working condition 3 (t) a second pressure acquisition unit; storing effective surface of throttleProduct A 1 The first memory cell of (a); a first processing unit for calculating the steady-state pressure P of the nozzle inlet under steady-state conditions 2 (t) satisfies:
wherein it is present>
Psi is the ratio of the throttle back pressure to the throttle front pressure under the steady-state working condition, and is greater than or equal to>
The unit is%; beta is the diameter ratio, the ratio of the throat diameter to the inlet diameter of the Venturi tube; d is the diameter of the throat, provided by a manufacturer, and is in a unit of m; lambda desired Looking up a table according to the rotating speed to obtain the required equivalence ratio;
a second calculation unit for calculating the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1); the second calculation unit includes: obtaining the temperature T before the throttle valve under the transient working condition 1 (t + 1) a temperature acquisition unit; a mass calculating unit for calculating mass deviation delta m under the transient working condition; a second processing unit for calculating the transient pressure delta P of the nozzle inlet under the transient working condition 2 (t + 1) satisfies:
wherein V is single cylinder displacement, in units of L; r is theoretical gas constant, 287J/(kg.K);
a third calculation unit for calculating the virtual pressure P behind the throttle valve 2 (t+1)＝P 2 (t)+ΔP 2 (t+1)。
7. The apparatus for calculating a virtual pressure behind a throttle valve according to claim 6, characterized in that the mass calculation unit includes:
calculating throttle flow Q under transient operating condition Thr A first flow amount calculation unit of (t + 1);
calculating the air flow Q of the nozzle under steady-state conditions Air (t) a second flow amount calculation unit;
a third processing unit, wherein the third processing unit calculates that the mass deviation Δ m under the transient working condition satisfies the following conditions:
wherein, K P Is an integral coefficient and can be calibrated.
8. The apparatus of calculating a virtual pressure behind a throttle valve according to claim 7, wherein the first flow amount calculation unit includes:
a fourth processing unit for calculating the throttle flow Q under the transient working condition Thr (t + 1) satisfies:
wherein the throttle front pressure P is determined in transient operating mode 1 (t + 1) is acquired by the first pressure acquisition unit.
9. The apparatus of calculating a virtual pressure behind a throttle valve according to claim 8, wherein the second flow amount calculation unit includes:
for calculating the flow Q of the mixture in the nozzle under steady-state conditions Noz (t) a third flow rate calculation unit;
a fifth processing unit calculating the air flow Q through the nozzle under steady state conditions Air (t) satisfies:
wherein λ is stoic Theoretical air-fuel gas with a constant of 16.7;
λ desired the required equivalence ratio is obtained by looking up a table according to the rotating speed.
10. The apparatus of calculating a virtual pressure behind a throttle valve according to claim 9, characterized in that the third flow amount calculation unit calculates a nozzle mixture flow rate Q in a steady-state operation Noz (t) satisfies:
wherein c is an outflow coefficient, a coefficient representing the relationship between the actual flow rate and the theoretical flow rate through the device is set to 1;
epsilon is an expandable coefficient and is set to be a constant 1;
beta is the diameter ratio, the ratio of the throat diameter to the inlet diameter of the Venturi tube, two sizes are provided by a manufacturer, and the unit is omitted by self calculation;
d is the diameter of the throat, provided by the manufacturer, in m;
ΔP 1 (t) is the pressure difference, Δ P, between the nozzle inlet and the nozzle outlet under steady-state conditions 1 (t)＝P 2 (t)-P 3 (t), unit Pa;
rho is the average density under the steady state working condition and the unit is kg/m 3 ，
T 1 (t) is the temperature before the throttle in steady state conditions, in K.
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| CN111206998A (en) * | 2019-12-31 | 2020-05-29 | 广西玉柴机器股份有限公司 | Method for controlling transient process of engine based on supercharging pressure deviation |
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| CN102733950A (en) * | 2012-06-27 | 2012-10-17 | 联合汽车电子有限公司 | Exhaust gas recirculation system assembly flow diagnosis method for electronic fuel injection management system of gasoline engine |
| CN106677912A (en) * | 2015-11-06 | 2017-05-17 | 联合汽车电子有限公司 | Novel method for acquiring zero position of electric waste gate of turbocharged engine in real time |
| CN112228234A (en) * | 2020-09-29 | 2021-01-15 | 广西玉柴机器股份有限公司 | Transient fuel control method and system of gas engine for power generation |
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