WO2005047681A1 - 内燃機関の排ガス浄化装置及び排ガス浄化方法 - Google Patents
内燃機関の排ガス浄化装置及び排ガス浄化方法 Download PDFInfo
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- WO2005047681A1 WO2005047681A1 PCT/JP2003/014374 JP0314374W WO2005047681A1 WO 2005047681 A1 WO2005047681 A1 WO 2005047681A1 JP 0314374 W JP0314374 W JP 0314374W WO 2005047681 A1 WO2005047681 A1 WO 2005047681A1
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- exhaust gas
- internal combustion
- engine
- combustion engine
- nox
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
- F02D41/0275—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a NOx trap or adsorbent
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
- F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
- F02D41/065—Introducing corrections for particular operating conditions for engine starting or warming up for starting at hot start or restart
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/12—Introducing corrections for particular operating conditions for deceleration
- F02D41/123—Introducing corrections for particular operating conditions for deceleration the fuel injection being cut-off
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/08—Introducing corrections for particular operating conditions for idling
Definitions
- the present invention relates to an exhaust gas purification apparatus and an exhaust gas purification method for an internal combustion engine.
- the present invention relates to an exhaust gas purifying apparatus and an exhaust gas purifying method for an internal combustion engine such as an automobile operating lean.
- An object of the present invention is to provide an exhaust gas purifying apparatus and an exhaust gas purifying method for an internal combustion engine which can exhibit high exhaust gas purifying performance even after the engine is restarted.
- the present invention provides a lean NOX catalyst in an exhaust gas passage of an internal combustion engine that is normally operated with a lean air-fuel ratio of 18 or more, such as a lean burn vehicle or a vehicle that directly injects fuel.
- a lean air-fuel ratio of 18 or more such as a lean burn vehicle or a vehicle that directly injects fuel.
- NOX in exhaust gas is trapped by the catalyst
- the operation is switched to a rich or stoichiometric operation before the internal combustion engine stops, and the NOX trapped in the catalyst is converted to HC, HC contained in the exhaust gas.
- the purpose is to reduce the fuel supply to the internal combustion engine by purifying the fuel and exhaust gas remaining in the engine cylinder and exhaust gas flow path by reducing it with a reducing agent such as CO and hydrogen.
- An internal combustion engine has an engine control unit (hereinafter, referred to as an engine control unit) that controls the engine based on various information input from the intake system and the exhaust system.
- an engine control unit that controls the engine based on various information input from the intake system and the exhaust system.
- the switching of the air-fuel ratio and the exhaust gas purge before the operation is stopped are performed by this ECU.
- the ECU may be provided with an engine stop prediction means for predicting engine stop in advance.
- the engine stop prediction means predicts engine stop by a preset judgment method. For example, it is predicted that the engine will be stopped in the following cases.
- the stoichiometric air-fuel ratio operation or the rich air-fuel ratio operation is temporarily performed, and then the concentration of unburned fuel—HC, CO, NOx, etc. in the exhaust gas decreases.
- Exhaust gas purge control is performed.
- a method of purging unburned fuel / exhaust gas a method of conveying intake air by forcing fuel supplied to an engine cylinder is preferable.
- the cylinders can be monitored using a star or an external motor. There is a method of driving and moving overnight.
- the following method is suitable as a method of moving the cylinder by driving a motor.
- the temperature of the lean NOx catalyst immediately before the exhaust gas purge is higher than a predetermined temperature (for example, 100 ° C or higher)
- oxygen in the air conveyed at the time of purging the exhaust gas and unburned fuel HC HC in the exhaust gas At least some of the reducing agent components such as CO and CO are burned on the catalyst and purified.
- an exhaust gas purging method there is a method of supplying secondary air to an exhaust gas channel using a pump or the like. This method may be performed subsequently to the method of conveying the intake air to the exhaust gas flow path.
- the ECU preferably also includes means for determining that the exhaust gas purge has been completed.
- the exhaust gas purge control As a specific method, for example, there is a method of determining the end of the exhaust gas purge control by measuring a predetermined time using a timer or the like. In addition, based on the concentration of unburned fuel and HC, C0 or NOX in the exhaust gas, the exhaust gas There is also a method of determining the end time of the page.
- a method for determining the end time of the exhaust gas purging based on the fuel and gas concentrations in the exhaust gas will be described.
- the detection means include an oxygen sensor for detecting oxygen concentration, an air-fuel ratio sensor, and a NOx sensor for detecting NOx concentration.
- These sensors may be installed anywhere that can detect the change in the concentration of the target gas component when purging the exhaust gas.However, the oxygen sensor and the air-fuel ratio sensor are located upstream of the lean NOX catalyst. It is desirable to install.
- a pre-catalyst such as a three-way catalyst is provided upstream of the lean N ⁇ x catalyst, it is desirable that the NOx sensor be installed upstream of the pre-catalyst.
- the reason for installing a NOX sensor upstream of the pre-catalyst is that the NOX concentration during the rich operation may decrease to several tens of ppm downstream of the pre-catalyst, and it is necessary to accurately measure the change in the NOX concentration during the exhaust gas purge. This is because it may be difficult.
- the N ⁇ X sensor can accurately measure a small amount of NOX concentration, it may be installed downstream of the precatalyst.
- the ECU determines that the engine can be stopped.
- a predetermined concentration eg, NOx concentration of 10 ppm in the case of the Nx sensor
- various sensors can be used as long as they can measure the concentration of the target component (HC, CO, NOx) in the exhaust gas, and are limited by the operating principle of the sensor. There is no.
- the catalyst temperature When using outside air for exhaust gas purging at idle stop, it is expected that the catalyst temperature will drop significantly and become lower than the catalyst activation temperature (for example, room temperature) when the engine is restarted.
- the catalyst activation temperature for example, room temperature
- an exhaust gas temperature sensor is provided upstream of the lean NOx catalyst.
- Exhaust gas temperature immediately before executing the exhaust gas purge control is measured by the exhaust gas temperature sensor and transmitted to the ECU.
- the ECU calculates the amount of air required to purge the exhaust gas remaining in the exhaust gas channel. Also calculate the catalyst temperature when the required total air amount is supplied to the exhaust gas purification catalyst. If the calculated value is lower than a predetermined temperature (for example, 100 ° C.), the ECU inhibits the idle stop control and does not stop the engine.
- a predetermined temperature for example, 100 ° C.
- Exhaust gas purging is performed until the temperature reaches a predetermined temperature (for example, 100 ° C.), and when the temperature reaches the predetermined temperature, the exhaust gas purging process is stopped.
- a predetermined temperature for example, 100 ° C.
- an outside air heating device is provided in the flow path through which the outside air flows.
- the outside air heating device shall be able to raise the inflowing outside air to a predetermined temperature.
- a method of obtaining the heat source of the outside air heating device there are a method of using a heat source such as electric heat and evening, and a method of exchanging and using waste heat of the engine room.
- a specific control example is as follows.
- the catalyst temperature when the necessary total air amount is supplied to the lean NOx catalyst is calculated in the same manner as described above. If the calculated value is lower than a predetermined temperature (for example, 100 ° C.), the calorie necessary for heating the outside air is calculated. Then, the outside air flowing in by the outside air heating device is raised to a predetermined temperature, and is conveyed to the exhaust gas passage.
- a predetermined temperature for example, 100 ° C.
- the driver may forcibly stop the engine (for example, turn off the ignition key). Even in such a case, the exhaust gas purging process is not interrupted, and the exhaust gas purging process is continued until it is determined that the exhaust gas purging is completed.
- information that predicts that the driver has stopped the engine stop operation such as returning from neutral to the drive position, depressing the accelerator pedal, or increasing the vehicle speed to, for example, 1 Okm / h or more before the engine stops, is generated by E. If transmitted to the CU, the exhaust gas purge is interrupted.
- the lean NOx catalyst captures NOx in the exhaust gas by adsorption, absorption or occlusion during lean operation, and the air-fuel ratio of the exhaust gas is stoichiometric (air-fuel ratio: 14.7) or rich (air-fuel ratio: 1).
- the trapped NOx when it becomes less than 4.7) means a catalyst that reduces and purifies the N 2.
- Such catalysts include the so-called NOx absorption (or storage) catalyst, which absorbs or stores NOx in lean exhaust gas in the form of nitrate ions inside the catalyst, or the NOx in lean exhaust gas on the surface of the catalyst. to chemisorption as NO 2, there is the so-called NOX adsorber catalyst, any may be used.
- FIG. 1 is a diagram showing the relationship between the NO X purification rate and temperature.
- FIG. 2 is a schematic diagram of an internal combustion engine showing one embodiment of the present invention.
- FIG. 3 is a system diagram showing the configuration of the ECU and the information taken into the ECU.
- FIG. 4 is a flowchart showing an example of a control flow of the present invention.
- FIG. 5 is a flowchart showing a control example of an engine stop predicting means.
- Fig. 6 is a schematic diagram of the change over time in the exhaust gas purge control.
- FIG. 7 is a schematic diagram of an internal combustion engine provided with a NOx sensor upstream of a lean NOx catalyst.
- FIG. 8 is a flowchart showing an example of a control flow when an NO x sensor is used.
- FIG. 9 is a schematic diagram of a change with time of the exhaust gas purge control when an NOx sensor is used.
- FIG. 10 is a schematic view of an internal combustion engine provided with a star.
- FIG. 11 is a diagram showing a change over time of control when a starter is used.
- FIG. 12 is a schematic diagram of an internal combustion engine having secondary air introduction means.
- FIG. 13 is a diagram showing a temporal change in control when secondary air introduction means is used.
- FIG. 14 is a diagram showing an example of control when the ignition switch is turned off during the exhaust gas purging process.
- FIG. 15 is a diagram showing an example of control after the ignition switch is turned off during the rich operation.
- Fig. 16 is a correlation diagram of catalyst temperature with respect to outside air temperature and carry-out air volume.
- FIG. 17 is a schematic diagram of an internal combustion engine having an exhaust gas temperature sensor.
- FIG. 18 is a control flow chart of an exhaust gas purifying apparatus having an exhaust gas temperature sensor.
- FIG. 19 is a map for estimating the total amount of air necessary to make the concentration of oxygen remaining in the exhaust gas flow path equal to or higher than a predetermined concentration (for example, 20%).
- FIG. 20 is a control flowchart of the external heating device.
- FIG. 21 is a map diagram of the outside air conveyance speed and the heater temperature of the outside air heating device required to keep the outside air at a predetermined temperature.
- Fig. 22 is a correlation diagram of the total energy required for the exhaust gas purge control with respect to the exhaust gas purge time.
- Figure 23 is a block diagram of an exhaust gas purification system equipped with a device that predicts the time until the engine restarts after idle stop.
- a supported NO x adsorption type lean NO x catalyst was prepared by the method described below, and the effect of the present invention was examined.
- Mg ⁇ average particle size: 30 m, specific surface area: lm 2 Zg
- the honeycomb was dried and fired to obtain 190 g of alumina and 10 g per liter of apparent honeycomb volume.
- an Mg ⁇ ⁇ ⁇ ⁇ -alumina-coated honeycomb coated with the same Mg ⁇ was obtained.
- the MgO-alumina coated honeycomb was impregnated with a solution of Ce nitric acid in water, dried at 200 ° C, and then fired at 600 ° C.
- Example catalyst 1 containing g, Na: 12.4 g, Li: 1.6 g, Ti: 4.3 g, and Mn: 13.7 g was obtained. Table 1 shows the catalyst composition. Table 1
- Example 1 Using the catalyst of Example 1, a test was performed assuming that the engine was stopped by purging residual exhaust gas after operation at a stoichiometric air-fuel ratio or less.
- the gas used for the test was a lean model gas simulating lean burn exhaust gas and a stoichiometric model gas simulating stoichiometric air-fuel ratio combustion.
- composition of the lean model gas NOX: 1 6 0 ppm, C 3 H 8: 4 0 0 ppm C l, CO: 0. 1%, CO,: 4%, O 2: 1 2%, H 2 0: 4%, N 2 : Residual.
- Scan Toy key composition of the model gas is N_ ⁇ X: 1 0 0 0 ppi, C 3 H 8: 6 0 0 ppm C 1, CO: 0. 5%, C 0 2: 5%, 0 2: 0. 5 %, H 2: 0. 3% , H 2 0: 1 0%, N 2: was the remainder.
- the test was performed according to the following procedure.
- the N ⁇ x ⁇ conversion rate was determined by the decrease rate of the N ⁇ x concentration before and after the catalyst layer flow with respect to the NO x concentration (160 ppm) supplied as the lean model gas. _ (160ppm—NOx concentration after catalyst layer distribution)
- test was conducted assuming that the engine was stopped without stoichiometric operation after lean operation and the engine was restarted. Using the same gas as in Test Example 1, the test was performed according to the following procedure.
- a stoichiometric operation is performed after the lean operation, but the engine is stopped with the stoichiometric gas remaining in the exhaust system, and then the engine is restarted.
- Figure 1 shows the results of Test Example 1, Test Example 2, and Test Example 3.
- Test Example 1 In contrast to Test Example 2, Test Example 1 exhibited excellent NO X purification performance at 100 ° C. or higher. Therefore, it is clear that a high NOx purification rate can be obtained from the low temperature region when the engine is restarted by performing the process of purging the stoichiometric model gas after the stoichiometric pretreatment.
- Test Example 1 showed excellent NO X purification performance at 150 ° C or lower compared to Test Example 3. Therefore, it is clear that purging the residual stoichiometric gas with air after the stoichiometric treatment can achieve a high N ⁇ X purification rate from the low temperature region when the engine is restarted.
- FIG. 2 shows an example of an internal combustion engine having the exhaust gas purifying catalyst of the present invention.
- This internal combustion engine is equipped with an intake system having a fuel-injectable engine 99, a fuel cell 4, an air cleaner 1, an air flow sensor 2, and a throttle valve 3 capable of lean combustion.
- an exhaust system having an air-fuel ratio sensor or an oxygen concentration sensor 7, an exhaust gas temperature sensor 8, a catalyst outlet gas temperature sensor 9, a lean NO x catalyst 10 and a pre-catalyst 13 is provided.
- a control unit (ECU; Engine Control Unit) 11 is provided.
- the engine 99 can intentionally repeat lean combustion with an air-fuel ratio of 18 or more and stoichiometric or rich combustion with an air-fuel ratio of 14.7 or less.
- the pre-catalyst 13 is for purifying exhaust gas near the stoichiometric air-fuel ratio
- the lean NO x catalyst 10 is for purifying N ⁇ X in lean exhaust gas.
- the ECU 11 is composed of IZ ⁇ and LSI as input / output interfaces, an arithmetic processing unit MPU, a storage RAM storing many control programs, R ⁇ ⁇ M, a timer counter, and the like. After the intake air to the engine is filtered by the air cleaner 1, it is measured by the air outlet sensor 2 and supplied to the engine 99 through the slot valve 3.
- the ECU 11 evaluates the operating state of the internal combustion engine and the state of the lean NOx catalyst to determine the operating air-fuel ratio, and controls the injection time of the injector 5 to set the fuel concentration of the mixture to a predetermined value. Set.
- the air-fuel mixture absorbed in the cylinder 1 is ignited by a spark plug 6 controlled by a signal from the ECU 11 and burns.
- the flue gas is led to an exhaust system.
- the lean NO x catalyst 10 purifies NO X by trapping NO X during lean operation, and at the same time purifies HC and C ⁇ by the combined combustion function. During stoichiometric or rich operation, the trapped N ⁇ X and exhaust gas NOx in the gas is purified by HC and CO that coexist in the exhaust gas.
- the NO X purification capacity of the lean NO X catalyst 10 is monitored continuously or intermittently by the ECU 11. If it is determined that the NOx trapping ability of the lean N ⁇ x catalyst has decreased, the air-fuel ratio of the combustion is shifted to the stoichiometric or rich side to restore the catalyst's NOx trapping ability. Is performed. As described above, exhaust gas is effectively purified under all engine combustion conditions in lean operation, stoichiometric or rich operation. Note that an AZF sensor may be used instead of the oxygen concentration sensor 7.
- the engine control unit ECU has an operating state determination unit and an air-fuel ratio control unit.
- the operating state determining means has NOx trapping amount estimating means in lean and NOx removing amount estimating means for reducing and purifying trapped NOx in stoichiometric or rich.
- the NOx trapping amount at an air-fuel ratio higher than the stoichiometric air-fuel ratio is estimated by the NOx trapping amount estimating means. If it is determined that the NOx trapping amount estimation means has exceeded a predetermined NOx trapping amount, that is, the reference value of the NOx trapping amount, the operating state determining means issues a command to the air-fuel ratio control unit to stop the operation.
- the toy or rich operation is performed, and the NOx removal amount estimating means estimates trapped NOx removal from the lean NOx catalyst.
- the operating state determination means issues a command to the air-fuel ratio control unit to perform the lean operation.
- the reference value of the NO x trapping amount is set so that the saturated N 0 X trapping amount of the N 0 X trapping material is measured in advance and is smaller than the saturated N 0 X trapping amount. Then, for example, 20% of the equilibrium adsorption amount at each exhaust gas temperature during operation is set as a reference value of the trapped amount of NOx. In lean operation, if the NOx trapping amount estimating means determines that the NOx trapping amount of the lean NOx catalyst has exceeded 20% of the equilibrium adsorption amount, the operation switches to stoichiometric or rich operation.
- the amount of trapped N ⁇ x can be estimated from the NOx concentration flowing into the lean NOx catalyst, the exhaust gas temperature, the exhaust gas flow rate, and the lean operation time. It is recommended that a speed formula, empirical formula, or map of the NOx trapping amount with respect to NOx concentration, exhaust gas temperature, exhaust gas flow rate, and lean operation time be prepared in advance, and these be prepared for the N ⁇ X trapping amount estimation means. . ,
- the NOx removal amount can be estimated from the temperature of exhaust gas flowing into the lean NOx catalyst, the exhaust gas flow rate, the stoichiometric or rich operation time, and the NOx trapping amount.
- the NOx removal rate, empirical formula, or map of NOx removal amount with respect to NOx trapping amount, exhaust gas temperature, exhaust gas flow rate, stoichiometric or rich operation time are determined in advance, and these are provided in the NOx removal amount estimation means. It is good to keep.
- the NO X concentration flowing into the lean NO X catalyst can be estimated from the air-fuel ratio.
- a NO X sensor may be provided upstream of the clean N ⁇ X catalyst to directly measure.
- Exhaust gas temperature can be measured by installing an exhaust gas temperature sensor upstream of the lean N ⁇ X catalyst. Exhaust gas flow rate, air flow sensor, boost pressure gauge And information from the engine tachometer and the like.
- NOx sensor information such as NOx sensor, oxygen sensor, exhaust gas temperature sensor, air flow sensor, boost pressure gauge and engine speed meter, lean operation time stoichiometry or rich operation are collected in the engine control unit. , NO x trapping amount and N 0 X removal amount are estimated.
- FIG. 3 shows an embodiment of an exhaust gas purifying apparatus for an internal combustion engine in which the present invention is applied to the above-described internal combustion engine.
- the ECU 11 includes an accelerator sensor 201 that detects depression of the accelerator pedal, a brake sensor 202 that detects depression of the brake pedal, and a transmission sensor 20 that detects the range of the transmission during operation. 3. Information is collected from the engine speed sensor 204, the vehicle speed sensor 205, and the air-fuel ratio sensor 206 that detects the air-fuel ratio of exhaust gas. Further, the ECU 11 includes an engine stop predicting means 207, an air-fuel ratio controlling means 208, and an exhaust gas purging means 209.
- FIG. 1 An example of the control flow of the present invention is shown in FIG.
- the air-fuel ratio control means 208 determines that operation at a stoichiometric air-fuel ratio or less (rich or stoichiometric) is necessary.
- the air-fuel ratio of the engine is set to rich or stoichiometric (1002).
- the exhaust gas purging means performs control to remove unburned fuel and at least one of H C, C O and hydrogen (1003).
- FIG. 5 shows a control example of the engine stop prediction means 207.
- the vehicle speed is detected by the vehicle speed sensor 205, it is determined that the vehicle speed is 10 km / h or less (1004), and the engine speed is detected by the engine speed sensor 204 to 100 O rpm. It is determined as follows (1005) and the brake sensor 202 If it is determined that the rake is being depressed (1006) and the transmission sensor 203 determines that the transmission is in the neutral range (1007), the engine is stopped. Is determined (1008).
- Fig. 6 shows the time-dependent change of the control according to the flow of Figs. 4 and 5 above.
- the engine stop prediction means starts the engine stop. Predict that will stop.
- the air-fuel ratio control means executes an operation at a stoichiometric air-fuel ratio or less (for example, rich) even during the lean operation.
- the rich operation time may be a predetermined time or may be determined according to the lean operation time immediately before the rich operation.
- the fuel After executing the rich operation, the fuel is cut and the intake air is conveyed to the exhaust gas passage.
- the exhaust gas purge control when it is determined that the fuel cut has been performed by the stoichiometric air-fuel ratio control, it is determined that the exhaust gas purge has started. When the exhaust gas purge is performed for a predetermined time, the exhaust gas purge is terminated.
- FIG. 7 shows an example in which a NOx sensor 12 is provided upstream of the precatalyst.
- the NOx sensor 12 can detect the NOx concentration in the exhaust gas channel.
- FIG. 8 shows an example of a control flow when the NOx sensor is used.
- the air-fuel ratio control means 208 determines that operation at a stoichiometric air-fuel ratio or less (rich or stoichiometric) is necessary.
- the engine's air-fuel ratio is set to rich or stoichiometric (1002).
- the exhaust gas purging means performs control to remove unburned fuel and at least one of HC, C ⁇ , and hydrogen.
- the NOx sensor 12 detects the NOx concentration in the exhaust gas passage (11010), and determines that the exhaust gas concentration is less than a predetermined amount (for example, 10 ppm) (1). 0 1 1), the exhaust gas purging means ends the exhaust gas purging (101 2).
- FIG. 9 shows an example of a change with time of the control based on FIGS. 7 and 8 described above.
- the N ⁇ X sensor provided upstream of the pre-catalyst measures the N ⁇ X concentration in the exhaust gas, and the exhaust gas purge is terminated when the NOx concentration in the exhaust gas becomes 1 Oppm or less. You.
- FIG. 10 shows an example of an internal combustion engine that performs exhaust gas purging using a starter.
- the engine 99 has a belt receiver 15.
- the belt receiver 15 is connected to the star 17 and the belt 16 so that the cylinder can be moved even if the engine cannot move the cylinder on its own due to fuel combustion. ing.
- FIG. 11 shows an example of a temporal change of the control based on FIG.
- the star when the fuel is cut and the intake air is conveyed to the exhaust gas flow path, the star
- An air introduction pump 18 is provided in the exhaust pipe 101, and the air introduction pump 18 is operated to convey air in the atmosphere to an exhaust gas flow path during exhaust gas purging.
- FIG. 13 shows an example of a temporal change of the control based on FIG.
- the air is introduced.
- the pump starts and carries air. If it is determined that the exhaust gas purge has been completed, the air introduction pump is stopped.
- FIG. 14 shows a control example in the third embodiment when the driver sets the ignition switch to 0 FF during the exhaust gas purging process.
- the N ⁇ x concentration measured by the NOX sensor upstream of the pre-catalyst is maintained at a predetermined concentration (for example, 1%). Exhaust gas purge is continued as long as it does not fall below (O ppm).
- FIG. 15 shows a control example in the third embodiment after the driver sets the ignition switch to OFF in the lit operation.
- the temperature of the clean NO X catalyst decreases according to the outside air temperature and the amount of air carried out at the time of exhaust gas purging.
- the temperature drop of the lean N ⁇ x catalyst at the time of purging the exhaust gas can be estimated as follows.
- the total heat (Q g) of the total air conveyed during the exhaust gas purging is obtained from the total conveyed air (F), the outside air temperature, and the specific heat of air. This transfer air volume If the total heat (Q g) is smaller than the heat (Q c) of the lean NO x catalyst before purging the exhaust gas (Q c> Q g), the heat of the catalyst becomes It is gradually taken away by the carrier air, and the temperature of the lean NOx catalyst decreases due to the exhaust gas purging process.
- the decrease in catalyst temperature with respect to the amount of carrier air is approximately as shown in Fig. 16.
- the temperature of the lean NOx catalyst may be lower than the temperature at which the catalytic activity occurs at the time of restarting the engine (for example, 100 ° C), depending on the total amount of the transported air. is there.
- Fig. 17 shows an example of an exhaust gas purification device.
- An exhaust gas temperature sensor 21 is provided at or upstream of the lean NOx catalyst, an outside air temperature sensor 22 is provided upstream of the air introduction pump 18, and an oxygen concentration sensor 23 is provided upstream of the lean NOx catalyst 10.
- the air introduction pump has an outside air heating device 24. The air introduction pump 24 with the outside air heating device can heat the outside air to a predetermined temperature based on information from the ECU.
- Figure 18 shows the control flow
- the exhaust gas temperature (Tc) immediately before executing the exhaust gas purge control is measured by the exhaust gas temperature sensor 21 and the temperature of the air used for exhaust gas purge (Tc) is measured. o) to the outside air temperature sensor 22
- the oxygen concentration (M02) remaining in the exhaust gas flow path is measured by the oxygen concentration sensor 23, and the respective information is transmitted to the ECU (2002).
- the ECU calculates the total amount of air (F) required to make the concentration of oxygen remaining in the exhaust gas flow path equal to or higher than a predetermined concentration (for example, 20%) (2003).
- the ECU may be provided with a theoretical formula for calculating the total amount of air required to bring the oxygen concentration to a predetermined concentration (for example, 20%) from the internal volume of the exhaust gas flow path and the residual oxygen concentration.
- a map as shown in Fig. 19 may be provided in advance. In the map shown in Fig. 19, if the oxygen concentration remaining in the exhaust gas flow path is MO2, the total amount of air required to bring the oxygen concentration to the predetermined concentration (20%) is determined to be Fa. .
- the ECU estimates the temperature (Td) of the catalyst after the total amount of air (Fa) has been passed through the lean NOx catalyst (204).
- the ECU may be equipped with a map of lean NO x catalyst temperature according to the air amount and the outside air temperature shown in Fig. 16 or a lean NO X catalyst according to the air amount and the outside air temperature.
- An estimation formula for estimating the temperature may be provided.
- the ECU determines that the estimated value (T d) is higher than a predetermined temperature (for example, 100 ° C.)
- the ECU performs a rich operation control (2006) and uses the outside air as it is to reduce the exhaust gas.
- Td is equal to or lower than the predetermined temperature
- execution of the rich operation control (209), execution of the outside air heating control (209), and purging of the exhaust gas using the finally heated outside air are performed. Execute the control (2 0 1 0).
- FIG. 1 An example of the control flow of the external heating device is shown in FIG. 1
- the ECU calculates the heater temperature of the outside air heater (HT), the outside air transfer from the estimated value of the lean NO X catalyst temperature (T d) at the completion of exhaust gas purging and the estimated value of the total air amount required for exhaust gas purging (F a).
- Speed (FT) Exhaust gas purge time (t) Is calculated (20001101), and control is performed so that each of the optimal values (HTm, FTm, tm) is obtained (20001102).
- the control start time (ts) is set to 0, and the time (ts) after the control is started is counted by a timer provided in the ECU. When the ts exceeds tm (2 0 0 1 0 4), the ECU discharges. It is determined that the gas purge control has been completed (20010).
- FIG. 21 shows an example of a map of the outside air transport speed (FT) and the temperature of the outside air heating device (HT) required to bring the outside air to a predetermined temperature (for example, 100 ° C.).
- the graph differs depending on the lean NOx catalyst temperature (Tdl and Td2; Tdl ⁇ Td2 ⁇ 100 ° C) at the completion of the exhaust gas purge.
- the control method when the lean NOx catalyst temperature at the completion of the exhaust gas purge is estimated to be Td1 is described below.
- the total energy (E) required for the exhaust gas purge control with respect to the exhaust gas purge time (t) is considered to be a function having a minimum value (Fig. 22).
- the exhaust gas purge time (tm) when the minimum value (Em) is reached, the outside air transport speed (FTm) and the outside air heating device heater temperature (HTm) that become the tm are control values.
- the control device can prevent a large decrease in the catalyst temperature at the time of purging the exhaust gas and maintain a high catalyst activity even when the engine is restarted.
- Figure 23 shows the control unit.
- the optimal time required for exhaust gas purging is estimated by the exhaust gas purge time control means from the NOx concentration remaining in the exhaust gas channel, the lean NOx catalyst temperature, and the outside air temperature.
- the optimum time is shorter than the predicted time until the engine is restarted, the optimum time is set as the exhaust gas purge time. If the optimal time is longer than the predicted time until the engine is restarted, the predicted time until the engine is restarted is set as the exhaust gas purge time.
- NOX on the downstream of the lean N 0 X catalyst, HC, the least even CO and ⁇ 2 may be provided with exhaust gas sensor for measuring the concentration of one type, for measuring the exhaust gas concentration in the exhaust gas purging process.
- the NOx concentration downstream of the lean NOx catalyst was 1 Oppm.
- the ECU determines that exhaust gas purging has been completed. Even if the predetermined exhaust gas purge time is not reached, if the ECU determines that the exhaust gas sensor downstream of the lean NOX catalyst has reached the predetermined concentration, the exhaust gas processing is terminated. Even if the predetermined exhaust gas purge time has elapsed, if the ECU determines that the exhaust gas sensor downstream of the lean NOX catalyst has not reached the predetermined concentration, the exhaust gas processing is continued.
- the following method can be used to predict the time from when the engine is stopped until the engine is restarted (hereinafter referred to as the predicted time).
- the ECU recognizes the location of the signal from the map information, and the signal waiting time is used as the predicted time.
- the ECU receives information on the predicted time, such as the stop time during traffic congestion at the driving point and the stop signal time of the traffic signal, or the predicted time through an advanced information communication terminal such as a road traffic information communication system.
- the predicted time is predicted by ECU based on the data from the advanced information communication terminal.
- the exhaust gas purification performance at the time of restart is reduced. Solved.
Abstract
Description
Claims
Priority Applications (3)
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PCT/JP2003/014374 WO2005047681A1 (ja) | 2003-11-12 | 2003-11-12 | 内燃機関の排ガス浄化装置及び排ガス浄化方法 |
AU2003280744A AU2003280744A1 (en) | 2003-11-12 | 2003-11-12 | Exhaust gas purification device for internal combustion engine and method of exhaust gas purification |
JP2005510564A JP4039443B2 (ja) | 2003-11-12 | 2003-11-12 | 内燃機関の排ガス浄化装置及び排ガス浄化方法 |
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PCT/JP2003/014374 WO2005047681A1 (ja) | 2003-11-12 | 2003-11-12 | 内燃機関の排ガス浄化装置及び排ガス浄化方法 |
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JP (1) | JP4039443B2 (ja) |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007239467A (ja) * | 2006-03-06 | 2007-09-20 | Nissan Motor Co Ltd | エンジンの排気浄化装置 |
WO2010055573A1 (ja) * | 2008-11-13 | 2010-05-20 | トヨタ自動車株式会社 | 内燃機関の排気浄化装置 |
CN103573442A (zh) * | 2012-07-30 | 2014-02-12 | 福特环球技术公司 | 操作内燃发动机的方法、断开内燃发动机的方法和发动机控制装置 |
CN104373233A (zh) * | 2013-08-15 | 2015-02-25 | 福特环球技术公司 | 两级催化剂再生 |
JP2019094801A (ja) * | 2017-11-20 | 2019-06-20 | マツダ株式会社 | エンジンの自動停止制御装置 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1061426A (ja) * | 1996-08-15 | 1998-03-03 | Toyota Motor Corp | 内燃機関の排気浄化方法及び装置 |
JPH10280987A (ja) * | 1997-04-03 | 1998-10-20 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
JP2000120428A (ja) * | 1998-10-19 | 2000-04-25 | Honda Motor Co Ltd | 内燃機関の排気浄化装置 |
-
2003
- 2003-11-12 JP JP2005510564A patent/JP4039443B2/ja not_active Expired - Fee Related
- 2003-11-12 AU AU2003280744A patent/AU2003280744A1/en not_active Abandoned
- 2003-11-12 WO PCT/JP2003/014374 patent/WO2005047681A1/ja active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1061426A (ja) * | 1996-08-15 | 1998-03-03 | Toyota Motor Corp | 内燃機関の排気浄化方法及び装置 |
JPH10280987A (ja) * | 1997-04-03 | 1998-10-20 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
JP2000120428A (ja) * | 1998-10-19 | 2000-04-25 | Honda Motor Co Ltd | 内燃機関の排気浄化装置 |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007239467A (ja) * | 2006-03-06 | 2007-09-20 | Nissan Motor Co Ltd | エンジンの排気浄化装置 |
JP4635913B2 (ja) * | 2006-03-06 | 2011-02-23 | 日産自動車株式会社 | エンジンの排気浄化装置 |
WO2010055573A1 (ja) * | 2008-11-13 | 2010-05-20 | トヨタ自動車株式会社 | 内燃機関の排気浄化装置 |
CN103573442A (zh) * | 2012-07-30 | 2014-02-12 | 福特环球技术公司 | 操作内燃发动机的方法、断开内燃发动机的方法和发动机控制装置 |
CN104373233A (zh) * | 2013-08-15 | 2015-02-25 | 福特环球技术公司 | 两级催化剂再生 |
JP2019094801A (ja) * | 2017-11-20 | 2019-06-20 | マツダ株式会社 | エンジンの自動停止制御装置 |
Also Published As
Publication number | Publication date |
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AU2003280744A8 (en) | 2005-06-06 |
JPWO2005047681A1 (ja) | 2007-06-14 |
AU2003280744A1 (en) | 2004-06-06 |
JP4039443B2 (ja) | 2008-01-30 |
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