CN113357030A - Exhaust gas recirculation EGR rate calculation method - Google Patents
Exhaust gas recirculation EGR rate calculation method Download PDFInfo
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- CN113357030A CN113357030A CN202110852848.7A CN202110852848A CN113357030A CN 113357030 A CN113357030 A CN 113357030A CN 202110852848 A CN202110852848 A CN 202110852848A CN 113357030 A CN113357030 A CN 113357030A
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- egr
- exhaust gas
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- oxygen storage
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/0047—Controlling exhaust gas recirculation [EGR]
- F02D41/0065—Specific aspects of external EGR control
- F02D41/0072—Estimating, calculating or determining the EGR rate, amount or flow
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- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust-Gas Circulating Devices (AREA)
Abstract
A method for calculating an EGR (exhaust gas recirculation) rate belongs to the technical field of automobile internal combustion engines. The method is more convenient and accurate in calculation, can better improve the combustion characteristic of the engine, and reduces oil consumption and emission. The method comprises the following steps: s1, after passing through an air filter and a throttle valve, fresh air and waste gas passing through an EGR cooling system are mixed and pressurized by a supercharger and then enter an intercooler for cooling; s2, the cooled mixed gas enters a pressure stabilizing cavity of the intake manifold through a throttle body and enters each cylinder to participate in combustion through pressure stabilization of the pressure stabilizing cavity; s3, respectively setting EGR gas taking positions before cooling the EGR system and after cooling the throttle body, and measuring the oxygen content of the EGR gas taking positions by using oxygen sensors; and S4, calculating the measured oxygen content to obtain the EGR rate. The method can calculate the EGR rate parameter of the engine with the cooling EGR system more conveniently and accurately, thereby better improving the combustion characteristic of the engine and reducing oil consumption and emission.
Description
Technical Field
The invention belongs to the technical field of automobile internal combustion engines, and particularly relates to an EGR rate parameter calculation method for an internal combustion engine with a cooling EGR system.
Background
With the rapid development of world economy and automobile industry, the quantity of reserved passenger vehicles continuously rises, the problems of energy consumption and environmental pollution are brought when the life of the vehicles is convenient and fast, the regulations on fuel consumption limit and pollutant emission limit of the passenger vehicles are upgraded and responded by each country, and with the continuous tightening of the oil consumption regulations, the gasoline engines of the passenger vehicles face unprecedented challenges, and the technology upgrading is not slow.
According to relevant researches, the cooling EGR system can effectively reduce the combustion temperature of mixed gas in a cylinder of a gasoline engine and improve the combustion in the cylinder, so that the engine knocking is inhibited, the ignition angle is advanced, the combustion efficiency is improved, and meanwhile, the problem that an oil injection enrichment strategy is adopted due to overhigh exhaust temperature under the large-load working condition of the engine is solved, so that the fuel consumption rate of the engine is reduced.
How to accurately and conveniently calculate the ratio of exhaust gas to fresh air entering the cylinder (i.e., the EGR rate) in a control system for a cooled EGR system becomes an important control strategy in a calibration system. At present, a CO2 content test method is generally adopted to calculate the EGR rate, but the accuracy of the EGR rate measurement is influenced greatly due to the problems of large fluctuation of CO2 in local environment, high requirement on test equipment and the like.
Disclosure of Invention
In order to solve the problems in the background art, the invention provides a method for calculating the EGR rate, which is more convenient and accurate to calculate, and can better improve the combustion characteristic of an engine and reduce oil consumption and emission.
The technical scheme adopted for solving the technical problems is as follows:
an exhaust gas recirculation EGR rate calculation method, comprising the steps of:
s1, after passing through an air filter and a throttle valve, fresh air and waste gas passing through an EGR cooling system are mixed and pressurized by a supercharger and then enter an intercooler for cooling;
s2, the cooled mixed gas enters a pressure stabilizing cavity of the intake manifold through a throttle body, and enters each cylinder to participate in combustion after being stabilized by the pressure stabilizing cavity;
s3, respectively setting EGR gas taking positions before cooling the EGR system and after cooling the throttle body, and measuring the oxygen content of the EGR gas taking positions by using oxygen sensors;
and S4, calculating the measured oxygen content to obtain the EGR rate.
In S1, the fresh air passes through the air cleaner and the throttle valve, enters the pressure end of the exhaust gas turbocharger together with the exhaust gas passing through the cooling EGR system, is stirred by the impeller of the exhaust gas turbocharger, is uniformly mixed, has increased temperature and pressure, and then enters the intercooler through the pipeline for cooling.
At S3, the EGR gas-taking position at the throttle body: a small part of mixed gas is led out from the rear part of the throttle body and enters an oxygen storage device I, and oxygen is arranged on the oxygen storage device ISensor one, for the oxygen content lambda in the mixed gas1And measuring, wherein the oxygen sensor is used for collecting the oxygen content ratio in the mixed gas of the waste gas and the fresh air.
And the air inlet pipe and the air outlet pipe of the first oxygen storage device are communicated with the pressure stabilizing cavity of the air inlet manifold.
In S2, the exhaust gas after the combustion of the cylinder enters a cooling EGR system after passing through a three-way catalyst, the rear end of the cooling EGR system is connected with an air filter, the air filter is provided with an introduction point, fresh air enters the supercharger together with the exhaust gas through the introduction point, and the introduction point is provided with a throttle valve for controlling the introduction amount of the exhaust gas.
At S3, the EGR gas taking position at the cooled EGR system: the exhaust gas passes through a second oxygen storage device before entering the cooling EGR system, and the oxygen content lambda in the exhaust gas is measured by a second oxygen sensor arranged on the second oxygen storage device2And the oxygen sensor is used for collecting the oxygen proportion in the waste gas after combustion.
The first oxygen sensor and the second oxygen sensor both adopt linear oxygen sensors, and the linear oxygen sensors have a self-heating function.
As shown in the figure, two structures of oxygen storage device one and oxygen storage device are the same, oxygen storage device one includes the shell body, sets up the intake pipe in shell body one side, sets up the outlet duct at the shell body other end, sets up the oxygen sensor mount pad in the shell body outside and sets up the oxygen storage chamber inside the shell body, relative setting about oxygen sensor mount pad and the oxygen storage chamber, the probe that oxygen sensor mount pad trompil was convenient for install oxygen sensor one inserts the oxygen storage intracavity, evenly be equipped with the gas pocket on the wall of oxygen storage chamber both sides.
And a heating patch for heating gas in the oxygen storage cavity is arranged on the side wall of the oxygen storage cavity close to the gas inlet pipe.
In S4, the measured lambda in the system is compared with the reference value1And λ2Substituting the value of the EGR valve into the following formula to obtain the EGR rate under the current working condition;
note that, in the formula, the content of oxygen in the atmosphere is shown.
The above formula is derived from the following basic formula,
VEGR×λ2+Vair conditioner×λAir conditioner＝VEGR×λ1+VAir conditioner×λ1
The invention has the beneficial effects that: the method can calculate the EGR rate parameter of the engine with the cooling EGR system more conveniently and accurately, thereby better improving the combustion characteristic of the engine and reducing oil consumption and emission.
Drawings
FIG. 1 is a schematic of the present invention;
FIG. 2 is a partial cross-sectional view of the oxygen storage device of the present invention;
in the figure: 1. an air cleaner; 2. a throttle valve; 3. cooling the EGR system; 4. a second oxygen storage device; 5. a second oxygen sensor; 6. a three-way catalyst; 7. an intake manifold; 8. a throttle body; 9. an intercooler; 10. a first oxygen sensor; 11. a first oxygen storage device; 111. an oxygen sensor mount; 112. an outer housing; 113. an air inlet pipe; 114. an oxygen storage chamber; 115. air holes; 116. heating the patch; 117. and an air outlet pipe.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.
An exhaust gas recirculation EGR rate calculation method, comprising the steps of:
s1, after passing through an air filter 1 and a throttle valve 2, fresh air and waste gas passing through an EGR cooling system 3 enter an intercooler 9 for cooling;
s2, the cooled mixed gas enters a pressure stabilizing cavity of an air inlet manifold 7 through a throttle body 8, is stabilized in pressure through the pressure stabilizing cavity and then enters each cylinder to participate in combustion;
s3, EGR gas taking positions are respectively arranged before the EGR system 3 and after the throttle body 8 are cooled, and oxygen content of the EGR gas taking positions is measured by using oxygen sensors;
and S4, calculating the measured oxygen content to obtain the EGR rate.
In S1, the fresh air passes through the air cleaner 1 and the throttle valve 2, enters the pressure end of the exhaust gas Turbocharger (TC) together with the exhaust gas passing through the EGR system 3, is stirred by the impeller of the exhaust gas turbocharger, is uniformly mixed, has increased temperature and pressure, and then enters the intercooler 9 through a pipeline for cooling.
At S3, the EGR gas taking position at the throttle body 8: a small part of mixed gas is led out from the rear part of the throttle body 8 and enters an oxygen storage device 11, an oxygen sensor 10 is arranged on the oxygen storage device 11, and the oxygen content lambda in the mixed gas is measured1The oxygen sensor I10 is used for collecting the oxygen ratio in the mixed gas of the waste gas and the fresh air.
The air inlet pipe 113 and the air outlet pipe 117 of the first oxygen storage device 11 are communicated with a pressure stabilizing cavity of the air inlet manifold 7 so as to reduce the influence of the testing system on the air inlet precision.
In S2, the exhaust gas after the combustion of the cylinder enters the cooled EGR system 3 after passing through the three-way catalyst 6, the rear end of the cooled EGR system 3 is connected to the air cleaner 1, the air cleaner 1 is provided with an introduction point, the fresh air enters the supercharger together with the exhaust gas through the introduction point, and the introduction point is provided with a throttle valve 2 for controlling the introduction amount of the mixed gas.
At S3, the EGR gas taking position at the cooled EGR system 3: the exhaust gas passes through the oxygen storage device II 4 before entering the cooling EGR system 3, and the oxygen content lambda in the exhaust gas is measured by the oxygen sensor II 5 arranged on the oxygen storage device II 42And the second oxygen sensor 5 is used for collecting the oxygen content in the combusted waste gas.
The first oxygen sensor 10 and the second oxygen sensor 5 both adopt linear oxygen sensors, and the linear oxygen sensors have a self-heating function.
As shown in fig. 2, the first oxygen storage device 11 and the second oxygen storage device 4 have the same structure, the first oxygen storage device 11 includes an outer shell 112, an air inlet pipe 113 disposed at one side of the outer shell 112, an air outlet pipe 117 disposed at the other end of the outer shell 112, an oxygen sensor mounting seat 111 disposed at the outer side of the outer shell 112, and an oxygen storage cavity 114 disposed inside the outer shell 112, the oxygen sensor mounting seat 111 and the oxygen storage cavity 114 are disposed oppositely, the oxygen sensor mounting seat 111 is provided with an opening for facilitating insertion of a probe for mounting the first oxygen sensor 10 into the oxygen storage cavity 114, and air holes 115 are uniformly disposed on two side walls of the oxygen storage cavity 114.
A heating patch 116 for heating the gas in the oxygen storage chamber 114 is installed on the side wall of the oxygen storage chamber 114 close to the gas inlet pipe 113.
In S4, the measured lambda in the system is compared with the reference value1And λ2Substituting the value of the EGR valve into the following formula to obtain the EGR rate under the current working condition;
note that in the formula, 20.95 is the oxygen content in the atmosphere.
The above formula is derived from the following basic formula,
VEGR×λ2+Vair conditioner×λAir conditioner＝VEGR×λ1+VAir conditioner×λ1
The calculation method can be applied to various combustion systems of the internal combustion engine, such as homogeneous combustion, lean combustion, stratified combustion and the like.
The calculation method can be suitable for calculating the EGR rate in a high-pressure EGR system, a low-pressure EGR system and a mixed EGR system.
It is to be understood that the present invention has been described with reference to certain embodiments, and that various changes in the features and embodiments, or equivalent substitutions may be made therein by those skilled in the art without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims (9)
1. An exhaust gas recirculation EGR rate calculation method characterized by: the method comprises the following steps:
s1, after passing through an air filter (1) and a throttle valve (2), fresh air and waste gas passing through a cooling EGR system (3) are mixed and pressurized by a supercharger and then enter an intercooler (9) for cooling;
s2, the cooled mixed gas enters a pressure stabilizing cavity of an air inlet manifold (7) through a throttle body (8), and enters each cylinder to participate in combustion after being stabilized by the pressure stabilizing cavity;
s3, EGR gas taking positions are respectively arranged in front of the EGR system (3) and behind the throttle body (8) and the oxygen content of the EGR gas taking positions is measured by using an oxygen sensor;
and S4, calculating the measured oxygen content to obtain the EGR rate.
2. The exhaust gas recirculation EGR rate calculation method according to claim 1, characterized in that: in S1, fresh air passes through the air filter (1) and the throttle valve (2) and then enters the pressure end of the exhaust gas turbocharger together with exhaust gas passing through the cooling EGR system (3), is stirred by the impeller of the exhaust gas turbocharger, then is uniformly mixed, is increased in temperature and pressure, and then enters the intercooler (9) through a pipeline for cooling.
3. The exhaust gas recirculation EGR rate calculation method according to claim 2, characterized in that: in S2, the exhaust gas after the combustion in the cylinder passes through the three-way catalyst (6) and enters the cooled EGR system (3).
4. The exhaust gas recirculation EGR rate calculation method according to claim 3, characterized in that: at S3, the EGR gas intake position at the throttle body (8): a small part of mixed gas is led out from the rear of the throttle body (8) and enters an oxygen storage device I (11), an oxygen sensor I (10) is arranged on the oxygen storage device I (11), and the oxygen content lambda in the mixed gas is measured1And measuring, wherein the first oxygen sensor (10) is used for collecting the oxygen content ratio in the mixed gas of the exhaust gas and the fresh air.
5. The exhaust gas recirculation EGR rate calculation method according to claim 4, characterized in that: at S3, the EGR gas taking position at the cooled EGR system (3): the exhaust gas passes through a second oxygen storage device (4) before entering the cooling EGR system (3), and the oxygen content lambda in the exhaust gas is measured by a second oxygen sensor (5) arranged on the second oxygen storage device (4)2And the second oxygen sensor (5) is used for collecting the oxygen content in the combusted waste gas.
6. The exhaust gas recirculation EGR rate calculation method according to claim 4, characterized in that: oxygen storage device (11) and oxygen storage device two (4) structure are the same, oxygen storage device (11) include shell body (112), set up intake pipe (113) in shell body (112) one side, set up outlet duct (117) at the shell body (112) other end, set up oxygen sensor mount pad (111) in the shell body (112) outside and set up in the inside oxygen storage chamber (114) of shell body (112), relative setting from top to bottom in oxygen sensor mount pad (111) and oxygen storage chamber (114), in oxygen sensor mount pad (111) trompil was convenient for install the probe of oxygen sensor (10) and was inserted oxygen storage chamber (114), evenly be equipped with gas pocket (115) on oxygen storage chamber (114) both sides wall.
7. The exhaust gas recirculation EGR rate calculation method according to claim 6, characterized in that: and the air inlet pipe (113) and the air outlet pipe (117) of the first oxygen storage device (11) are communicated with the pressure stabilizing cavity of the air inlet manifold (7).
8. The exhaust gas recirculation EGR rate calculation method according to claim 6, characterized in that: and a heating patch (116) for heating the gas in the oxygen storage cavity (114) is arranged on the side wall of the oxygen storage cavity (114) close to the gas inlet pipe (113).
9. The exhaust gas recirculation EGR rate calculation method according to claim 5, characterized in that: in S4, the measured lambda in the system is compared with the reference value1And λ2Substituting the value of the EGR valve into the following formula to obtain the EGR rate under the current working condition;
note that in the formula, 20.95 is the oxygen content in the atmosphere.
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| CN202110852848.7A CN113357030A (en) | 2021-07-27 | 2021-07-27 | Exhaust gas recirculation EGR rate calculation method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114941593A (en) * | 2022-06-08 | 2022-08-26 | 哈尔滨东安汽车动力股份有限公司 | Measuring device and measuring method for EGR (exhaust gas Recirculation) rate of internal combustion engine |
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2021
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114941593A (en) * | 2022-06-08 | 2022-08-26 | 哈尔滨东安汽车动力股份有限公司 | Measuring device and measuring method for EGR (exhaust gas Recirculation) rate of internal combustion engine |
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Application publication date: 20210907 |
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