JP7396182B2 - engine equipment - Google Patents

Description

The present invention relates to an engine device.

Conventionally, this type of engine device delays fuel cut if the temperature of a catalyst attached to an exhaust pipe connected to an engine exhaust port is higher than a threshold value when engine fuel cut conditions are met. In addition, a method has been proposed in which the target air-fuel ratio during the fuel cut delay period is set to be leaner than the stoichiometric air-fuel ratio (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2009-191665

In such engine devices, non-ignition control is sometimes performed on the engine, in which fuel is injected without ignition, in order to warm up the catalyst, etc., but in this case, the fluid (exhaust gas) flowing through the exhaust port of the engine A method for estimating the temperature had not been devised.

The main purpose of the engine device of the present invention is to make it possible to estimate the temperature of fluid flowing through an exhaust port of an engine when non-ignition control is executed.

The engine device of the present invention employs the following means to achieve the above-mentioned main purpose.

The engine device of the present invention includes:
an engine having a fuel injector and a spark plug;
a catalyst attached to an exhaust pipe connected to an exhaust port of the engine;
a control device that controls the engine;
An engine device comprising:
When the control device executes non-ignition control in which fuel is injected from the fuel injection valve without ignition by the spark plug as control of the engine, the control device controls the mist of fuel injected from the fuel injection valve. estimating the temperature of the fluid flowing through the exhaust port, taking into account the oxidation delay and assuming that part of the atomized fuel is combusted in the cylinders of the engine;
The gist is that.

In the engine device of the present invention, when non-ignition control is performed to control the engine, in which fuel is injected from the fuel injection valve without ignition using the spark plug, there is a delay in atomization of the fuel injected from the fuel injection valve. In addition, the temperature of the fluid flowing through the exhaust port is estimated assuming that a portion of the atomized fuel is combusted in the engine cylinder. In this way, the temperature of the fluid flowing through the exhaust port when non-ignition control is being executed can be estimated. The inventors confirmed this through experiments and analysis.

In the engine device of the present invention, when executing the no-ignition control, the control device performs a smoothing process using a time constant on the injection amount injected from the fuel injection valve to atomize the fuel. estimating the atomization amount, estimating the amount of heat generated by combustion of the atomized fuel based on the amount of atomization and the reaction rate of combustion in the cylinder, and controlling the exhaust port in consideration of the amount of heat generated. The temperature of the flowing fluid may be estimated. In this way, the temperature of the fluid flowing through the exhaust port can be estimated more appropriately.

1 is a configuration diagram schematically showing the configuration of an engine device 10 as an example of the present invention. 7 is an explanatory diagram showing an example of input/output signals of the electronic control unit 70. FIG. 7 is a flowchart illustrating an example of a processing routine executed by the electronic control unit 70. FIG. FIG. 2 is an explanatory diagram showing an example of a time constant setting map. It is an explanatory view showing an example of a heat reception rate setting map. 7 is a flowchart illustrating an example of a processing routine executed by the electronic control unit 70. FIG.

Next, a mode for carrying out the present invention will be described using examples.

FIG. 1 is a block diagram schematically showing the structure of an engine device 10 as an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of input/output signals of the electronic control unit 70. The engine device 10 of the embodiment is installed in a general automobile or various hybrid automobiles, and as shown in FIGS. 1 and 2, includes an engine 12, a supercharger 40, and an electronic control unit 70 as a control device. Equipped with

The engine 12 is configured as a multi-cylinder (for example, 4-cylinder, 6-cylinder, etc.) internal combustion engine that outputs power through four strokes of intake, compression, expansion, and exhaust using hydrocarbon fuel such as gasoline or diesel oil. ing. This engine 12 sucks air purified by an air cleaner 22 into an intake pipe 23 and passes it through an intercooler 25, a throttle valve 26, and a surge tank 27 in this order. Then, fuel is injected into the air sucked into the combustion chamber 30 through the intake port 29 from the in-cylinder injection valve 28 attached to the combustion chamber 30 to mix the air and fuel, and an electric spark from the ignition plug 31 causes an explosion. Burn it. The intake port 29 is opened and closed by an intake valve 29a. The engine 12 converts the reciprocating motion of the piston 32, which is pushed down by the energy generated by the explosive combustion, into rotational motion of the crankshaft 14. Exhaust gas from the combustion chamber 30 is discharged to an exhaust pipe 35 connected to an exhaust port 34, and is discharged to the outside air via purifiers 37, 38 attached to the exhaust pipe 35. The exhaust port 34 is opened and closed by an exhaust valve 34a. The purification devices 37 and 38 have catalysts (three-way catalysts) 37a and 38a that purify harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). Hereinafter, a portion of the exhaust pipe 35 upstream of the purification device 37, a portion between the purification devices 37 and 38, and a portion downstream of the purification device 38 will be referred to as "first exhaust pipe section 35a" and "first exhaust pipe section 35a," respectively. 2 exhaust pipe section 35b" and "third exhaust pipe section 35c."

The supercharger 40 is configured as a turbocharger and includes a turbine 41, a compressor 42, a wastegate valve 44, and a blow-off valve 45. The turbine 41 is disposed on the upstream side (first exhaust pipe portion 35a) of the exhaust pipe 35 with respect to the purifying device 37. The compressor 42 is disposed upstream of the intercooler 25 in the intake pipe 23 and is connected to the turbine 41 via a connecting shaft 43. Compressor 42 is therefore driven by turbine 41 . The wastegate valve 44 is provided in a bypass pipe 36 that connects the upstream side and the downstream side of the turbine 41 of the exhaust pipe 35, and is controlled by the electronic control unit 70. The blow-off valve 45 is provided in the bypass pipe 24 that communicates the upstream side and the downstream side of the compressor 42 of the intake pipe 23, and is controlled by the electronic control unit 70.

In this supercharger 40, by adjusting the opening degree of the waste gate valve 44, the distribution ratio between the exhaust gas flowing through the bypass pipe 36 and the exhaust gas flowing through the turbine 41 is adjusted, and the rotational driving force of the turbine 41 is adjusted. The amount of compressed air by the compressor 42 is adjusted, and the supercharging pressure (intake pressure) of the engine 12 is adjusted. Here, the distribution ratio is adjusted so that, in detail, the smaller the opening degree of the waste gate valve 44, the smaller the amount of exhaust gas flowing through the bypass pipe 36 and the larger the amount of exhaust gas flowing through the turbine 41. Note that when the wastegate valve 44 is fully open, the engine 12 operates similarly to a naturally aspirated engine that does not include the supercharger 40.

In addition, in the supercharger 40, when the pressure on the downstream side of the compressor 42 in the intake pipe 23 is higher than the pressure on the upstream side to some extent, by opening the blow-off valve 45, the surplus on the downstream side of the compressor 42 is Pressure can be released. Note that the blow-off valve 45 is configured as a check valve that opens when the pressure downstream of the compressor 42 in the intake pipe 23 becomes higher than the pressure upstream to some extent, instead of a valve controlled by the electronic control unit 70. It is also possible to do so.

The electronic control unit 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, a nonvolatile flash memory, and an input/output port. , equipped with a communication port. As shown in FIG. 2, signals from various sensors are input to the electronic control unit 70 via input ports.

Signals input to the electronic control unit 70 include, for example, the crank angle θcr from the crank position sensor 14a that detects the rotational position of the crankshaft 14 of the engine 12, and the water temperature (not shown) that detects the temperature of the cooling water of the engine 12. Examples include the cooling water temperature Tw from the sensor and the throttle opening TH from the throttle position sensor 26a that detects the opening of the throttle valve 26. The cam position θca may be detected from a cam position sensor (not shown) that detects the rotational position of the intake camshaft that opens and closes the intake valve 29a and the exhaust camshaft that opens and closes the exhaust valve 34a. The amount of intake air Qa from the air flow meter 23a installed upstream of the compressor 42 in the intake pipe 23, the intake pressure Pin from the intake pressure sensor 23b installed upstream of the compressor 42 in the intake pipe 23, and the intake air The boost pressure Pc from the boost pressure sensor 23c attached between the compressor 42 of the pipe 23 and the intercooler 25 can also be mentioned. The surge pressure Ps from the surge pressure sensor 27a attached to the surge tank 27 and the surge temperature Ts from the temperature sensor 27b attached to the surge tank 27 can also be mentioned. The air-fuel ratio AF from the air-fuel ratio sensor 39a attached to the upstream side of the purification device 37 of the exhaust pipe 35 (first exhaust pipe section 35a), and between the purification devices 37 and 38 of the exhaust pipe 35 (second exhaust pipe section 35a). Mention may also be made of the oxygen signal O2 from the oxygen sensor 39b attached to 35b). The atmospheric pressure Pout from the atmospheric pressure sensor 71 and the outside temperature Tout from the outside temperature sensor 72 can also be mentioned.

Various control signals are output from the electronic control unit 70 via an output port. Examples of the signals output from the electronic control unit 70 include a control signal to the throttle valve 26, a control signal to the in-cylinder injection valve 28, and a control signal to the spark plug 31. A control signal to the wastegate valve 44 and a control signal to the blow-off valve 45 can also be mentioned.

The electronic control unit 70 calculates the rotation speed Ne of the engine 12 based on the crank angle θcr from the crank position sensor 14a. Further, the electronic control unit 70 calculates the load factor (the air actually taken in in one cycle with respect to the stroke volume per one cycle of the engine 12) based on the intake air amount Qa from the air flow meter 23a and the rotation speed Ne of the engine 12. (volume ratio) KL is calculated.

In the engine device 10 of the embodiment configured in this way, the electronic control unit 70 basically executes normal control as control of the engine 12. Normal control includes intake air amount control that controls the opening degree of the throttle valve 26, fuel injection control that controls the amount of fuel injected from the in-cylinder injection valve 28, and spark plug control based on the required load factor KL* of the engine 12. It performs ignition control to control the ignition timing of 31, supercharging control to control the opening degree of waste gate valve 44, etc. Note that, as described above, when the wastegate valve 44 is fully open, the engine 12 operates in the same manner as a naturally aspirated engine that does not include the supercharger 40.

Further, in the engine device 10 of the embodiment, the electronic control unit 70 executes the no-ignition control as a control of the engine 12 when warming up of the catalyst 37a of the purification device 37 is requested when the fuel cut condition is satisfied. do. In the non-ignition control, a small amount of fuel is injected from the in-cylinder injection valve 28 without performing ignition control or supercharging control (ignition is not performed by the spark plug 31 and the waste gate valve 44 is opened). Note that, as the fuel cut condition, for example, a condition in which the accelerator is turned off in the vehicle in which the engine device 10 is mounted is used. Warming up of the catalyst 37a is performed, for example, when it is assumed that the catalyst 37a is not activated because the water temperature Tw of the engine 12 is less than the threshold value Twref. When non-ignition control is being executed, at least a portion of the fuel injected from the in-cylinder injection valve 28 is atomized with a delay, and a portion of the atomized fuel enters the combustion chamber 30 near the top dead center of the compression stroke. At the same time, at least a portion of the remaining atomized fuel is combusted (reacted) at the catalyst 37a. The inventors confirmed this through experiments and analysis. In the embodiment, for the sake of simplicity, it is assumed that a portion of the atomized fuel is combusted within the combustion chamber 30, and the remainder is combusted in the catalyst 37a.

Next, the operation of the engine device 10 configured in this manner will be explained. In particular, a process for estimating the temperature Tep of the fluid (exhaust gas) flowing through the exhaust port 34, the temperature Tcat of the catalyst 37a of the purification device 37, etc. when non-ignition control is executed as control of the engine 12 will be described. In the embodiment, the temperature of the merging portion where the exhaust ports 34 of each cylinder merge is estimated as the temperature Tep of the fluid flowing through the exhaust ports 34. FIG. 3 is a flowchart showing an example of a processing routine executed by the electronic control unit 70. This routine is repeatedly executed when fuel is injected from the in-cylinder injection valve 28 (when normal control or non-ignition control is executed as control of the engine 12).

When the processing routine of FIG. 3 is executed, the electronic control unit 70 first determines whether or not no-ignition control is being executed to control the engine 12 (step S100). When it is determined that no-ignition control is being executed to control the engine 12, the engine 12 rotation speed Ne, the load factor KL, the flow velocity Vep of the fluid (exhaust) flowing through the exhaust port 34, and the no-ignition control are executed. Data such as the non-ignition total injection amount Qfcyc, which is the fuel injection amount for one cycle (two rotations of the engine 12), is input (step S110).

Here, for the rotational speed Ne, a value calculated based on the crank angle θcr from the crank position sensor 14a is input. As for the load factor KL, a value calculated based on the intake air amount Qa from the air flow meter 23a and the rotational speed Ne is input. Regarding the flow velocity Vep of the fluid flowing through the exhaust port 34, a value calculated based on the rotation speed Ne of the engine 12 and the load factor KL is input. Regarding the non-ignition total injection amount Qfcyc, a value calculated as the sum of the fuel injection amounts Qf(i) of each cylinder when non-ignition injection control is executed is input.

Next, based on the previously estimated temperature (previous Tgci) of the catalyst fluid input (inflowing) to the catalyst 37a of the purification device 37, the temperature of the in-cylinder injection valve 28 when executing the non-ignition control is determined. A time constant τ for simulating the delay until the injected fuel is atomized is estimated (step S120). Then, the total non-ignition injection amount Qfcyc for one cycle is subjected to an annealing process using the time constant τ, and the total atomization amount Qatm that is atomized in all combustion chambers 30 (each The total amount of atomization atomized within the combustion chamber 30 of the cylinder is estimated (step S130). In the embodiment, as shown in equation (1), the total atomization amount Qatm is estimated by dividing the total non-ignition injection amount Qfcyc for one cycle by the time constant τ. In formula (1) and each of the following formulas, units are shown in square brackets.

Qatm=Qfcyc/τ (1)

Here, in the embodiment, the time constant τ is set by applying the previous temperature of the fluid entering the catalyst (previous Tgci) to the time constant setting map. The time constant setting map is predetermined by experiment or analysis as a relationship between the previous temperature of the fluid entering the catalyst (previous Tgci) and the time constant τ, and is stored in a ROM or flash memory (not shown). FIG. 4 is an explanatory diagram showing an example of a time constant setting map. As shown in the figure, the time constant τ is set to be smaller within a range larger than the value 1 as the previous temperature of the fluid entering the catalyst (previous Tgci) is higher. This is because the higher the temperature of the fluid entering the catalyst last time (previous Tgci), the higher the temperature inside the combustion chamber 30, and the more easily the fuel injected from the in-cylinder injection valve 28 is atomized in a short time.

When the total amount of atomization Qatm atomized in the combustion chamber 30 is estimated in this way, the total amount of combustion Qcylcmb is estimated as the product of the total amount of atomization Qatm and the reaction rate Rcyl (step S160). Here, the reaction ratio Rcyl and the total combustion amount Qcylcmb are the reaction ratio and total combustion amount (each cylinder is the total amount of combustion burned in the combustion chamber 30. In the examples, a value predetermined by experiment or analysis is used for the reaction rate Rcyl.

Qcylcmb=Qatm・Rcyl (2)

Subsequently, as shown in equation (3), the estimated total combustion amount Qcylcmb is multiplied by the combustion calorific value ΔQcylcal and divided by the specific heat κg of the fluid flowing through the exhaust port 34 to estimate the temperature rise amount ΔTcylcal (step S170 ). Here, the combustion calorific value ΔQcylcal and the temperature rise amount ΔTcylcal are the unit mass when a part of the atomized fuel is combusted (reacted) by a low-temperature oxidation reaction in the combustion chamber 30 near the top dead center of the compression stroke, respectively. The calorific value per cylinder and the total calorific value (the sum of the calorific value of combustion within the combustion chamber 30 of each cylinder). The combustion calorific value ΔQcylcal may be a constant determined in advance through experiment or analysis, or may be determined based on the ignition timing of the spark plug 31 or the like. The specific heat κg of the fluid flowing through the exhaust port 34 may be a constant determined in advance through experiment or analysis, or may be determined based on the alcohol concentration of the fuel detected by an alcohol concentration sensor (not shown). Good too.

ΔTcylcal=Qcylcmb・ΔQcylcal/κg (3)

Next, based on the engine speed Ne and load factor KL of the engine 12, the temperature of the fluid flowing through the exhaust port 34 (hereinafter referred to as "basic temperature") when combustion due to low-temperature oxidation reaction in the combustion chamber 30 is not considered. Tepbs is estimated (step S180). Next, based on the flow velocity Vep of the fluid flowing through the exhaust port 34, the heat reception ratio Rhr of the fluid flowing through the exhaust port 34 with respect to the temperature rise amount ΔTcylcal estimated at step S170 is set (step S190).

Here, in the embodiment, the heat reception rate Rhr is set by applying the flow velocity Vep of the fluid flowing through the exhaust port 34 to the heat reception rate setting map. The heat reception ratio setting map is predetermined by experiment or analysis as the relationship between the flow velocity Vep of the fluid flowing through the exhaust port 34 and the heat reception ratio Rhr, and is stored in a ROM or flash memory (not shown). FIG. 5 is an explanatory diagram showing an example of a heat reception rate setting map. As shown in the figure, the heat reception rate Rhr is set within a range larger than the value 0 and smaller than the value 1, and becomes smaller as the flow velocity Vep of the fluid flowing through the exhaust port 34 becomes larger. This is because the higher the flow velocity Vep of the fluid flowing through the exhaust port 34, the more difficult it is for the heat generated by combustion due to the low-temperature oxidation reaction in the combustion chamber 30 to be transferred to the fluid flowing through the exhaust port 34.

When the heat reception rate Rhr is set in this way, as shown in equation (4), the basic temperature Tepbs of the fluid flowing through the exhaust port 34 and the value obtained by multiplying the temperature rise amount ΔTcylcal estimated in step S170 by the heat reception rate Qhr (heat reception amount) The temperature Tep of the fluid flowing through the exhaust port 34 is estimated as the sum of (step S200).

Tep=Tepbs＋ΔTcylcal・Rhr (4)

In the embodiment, when non-ignition control is executed, at least a portion of the fuel injected from the in-cylinder injection valve 28 is atomized with a delay, and a portion of the atomized fuel is at a low temperature within the combustion chamber 30. In consideration of combustion due to an oxidation reaction, specifically, the temperature Tep of the fluid flowing through the exhaust port 34 is estimated in consideration of the temperature increase amount ΔTcylcal estimated in step S170. Thereby, the temperature Tep of the fluid flowing through the exhaust port 34 can be estimated more appropriately than the method of estimating the temperature Tep of the fluid flowing through the exhaust port 34 without considering the temperature increase amount ΔTcylcal.

After estimating the temperature Tep of the fluid flowing through the exhaust port 34 in step S200, the temperature Tgci of the fluid containing the catalyst is estimated based on the estimated temperature Tep of the fluid flowing through the exhaust port 34 (step S210). In the embodiment, in addition to the temperature Tep of the fluid flowing through the exhaust port 34, the amount of heat transfer Hge between the fluid (exhaust gas) flowing through the first exhaust pipe section 35a and the first exhaust pipe section 35a is considered, The temperature Tgci of is estimated. Note that this heat transfer amount Hge increases as the temperature difference between the temperature Tep of the fluid flowing through the exhaust port 34 (the temperature of the fluid flowing through the first exhaust pipe section 35a) and the temperature Tex of the first exhaust pipe section 35a increases. .

When the temperature Tgci of the fluid containing the catalyst is estimated in this way, as shown in equation (5), the total atomization amount Qatm estimated in step S130 is equal to the value (1-Rcyl) obtained by subtracting the above-mentioned reaction rate Rcyl from the value 1. The total combustion amount (fuel amount) Qcatcmb is estimated as the product (step S220). Here, the total combustion amount Qcatcmb is the total combustion amount of the atomized fuel (total atomization amount Qatm) combusted by the catalyst 37a.

Qcatcmb=Qatm・(1−Rcyl) (5)

Subsequently, as shown in equation (6), the total calorific value Qcatcal is estimated as the product of the estimated total combustion amount Qcatcmb and the combustion calorific value ΔQcatcal (step S230). Here, the combustion calorific value ΔQcatcal and the total calorific value Qcalcal are the calorific value per unit mass and the total calorific value, respectively, when a part of the atomized fuel is combusted (reacted) in the catalyst 37a. The combustion calorific value ΔQcatcal may be a constant determined in advance through experiment or analysis, or may be determined based on the ignition timing of the spark plug 31 or the like.

Qcatcal=Qcatcmb・ΔQcatcal (6)

Next, as shown in equation (7), the sum of the temperature Tgci of the catalyst-containing fluid estimated in step S210 multiplied by the heat capacity Cg of the catalyst-containing fluid and the total calorific value Qcatcal estimated in step S230 is expressed as: The amount of heat Qgcat of the fluid entering the catalyst (inflow) into the catalyst 37a is estimated (step S240), and the amount of heat Qgcat of the fluid entering the catalyst is estimated based on the previously estimated temperature of the catalyst 37a (previous Tcat) and the amount of heat Qgcat of the fluid entering the catalyst. The temperature Tcat is estimated (step S250), and this routine ends. Here, the heat capacity Cg of the catalyst-containing fluid is set in advance, for example, by experiment or analysis.

Qgcat=Tgci・Cg＋Qgcatcal (7)

The temperature Tcat of the catalyst 37a is determined by, for example, the amount of heat Qcat obtained by multiplying the previously estimated temperature of the catalyst 37a (previous Tcat) by a conversion coefficient, the amount of heat Qgcat of the fluid containing the catalyst, or the amount of heat between the catalyst 37a and the fluid containing the catalyst. It can be estimated by considering the amount of heat exchange Hgci, the amount of heat exchange Hgco between the catalyst 37a and the catalyst fluid output from the catalyst 37a, and the total heat capacity Cgc of the fluid and the catalyst 37a. Here, the heat exchange amounts Hgci and Hgco are based on the previously estimated temperature of the catalyst 37a (previous Tcat) (calorific value Qcat) and the calorific value Qgcat of the fluid entering the catalyst.

In the embodiment, as described above, since the temperature Tep of the fluid flowing through the exhaust port 34 can be estimated more appropriately, the temperature Tgci of the fluid entering the catalyst and the The temperature Tcat of the catalyst 37a can also be estimated more appropriately. When the temperature Tcat of the catalyst 37a is estimated in this way, in addition to the temperature Tgco of the catalyst output fluid output from the catalyst 37a (which has passed through the catalyst 37a) based on the temperature Tgci of the fluid entering the catalyst and the temperature Tcat of the catalyst 37a, Taking into consideration the amount of heat transfer Hge2 between the fluid (exhaust gas) flowing through the pipe portion 35b and the second exhaust pipe portion 35b, the temperature Tgci2 of the second catalyst input fluid input (inflowing) to the catalyst 38a is estimated, and 2. The temperature Tcat2 of the catalyst 38a is estimated based on the temperature Tgci2 of the fluid entering the catalyst. Note that this heat transfer amount Hge2 increases as the temperature difference between the temperature Tgco of the catalyst output fluid (temperature of the fluid flowing through the second exhaust pipe section 35b) and the temperature Tex2 of the second exhaust pipe section 35b increases.

When it is determined in step S100 that the no-ignition control is not being executed as the control of the engine 12, that is, when it is determined that the normal control is being executed as the control of the engine 12, the rotation speed Ne of the engine 12 and the load factor KL , data such as the flow velocity Vep of the fluid (exhaust gas) flowing through the exhaust port 34 are input (step S140). Subsequently, the total atomization amount Qatm based on the non-ignition control is set to a value of 0 (step S150), and the processes from step S160 onwards are executed. In this case, since the total atomization amount Qatm has a value of 0, the total combustion amount Qcylcmb has a value of 0 in step S160, and the temperature increase amount ΔTcylcal has a value of 0 in step S170. Then, in step S200, the second term on the right side of equation (4) becomes 0, and the basic temperature Tepbs of the fluid flowing through the exhaust port 34 is estimated as the temperature Tep.

In the engine device 10 of the embodiment described above, when non-ignition control is executed, at least a portion of the fuel injected from the in-cylinder injection valve 28 is atomized with a delay, and a portion of the atomized fuel is The temperature Tep of the fluid flowing through the exhaust port 34 is estimated in consideration of the fact that is burned in the combustion chamber 30 by a low-temperature oxidation reaction, and specifically, in consideration of the temperature rise amount ΔTcylcal estimated in step S170. Thereby, the temperature Tep of the fluid flowing through the exhaust port 34 can be estimated more appropriately than the method of estimating the temperature Tep of the fluid flowing through the exhaust port 34 without considering the temperature increase amount ΔTcylcal.

In the engine device 10 of the embodiment, the process of estimating the temperature Tep of the fluid (exhaust gas) flowing through the exhaust port 34, the temperature Tcat of the catalyst 37a of the purification device 37, etc. when non-ignition control is executed as the control of the engine 12 is performed. explained. On the other hand, when the engine 12 is stopped, the electronic control unit 70 estimates the temperature Tcat of the catalyst 37a using the processing routine shown in FIG. This routine is repeatedly executed when the engine 12 is stopped.

When the processing routine of FIG. 6 is executed, the electronic control unit 70 first inputs the temperature Tex of the first exhaust pipe section 35a (step S300). Here, regarding the temperature Tex of the first exhaust pipe portion 35a, the temperature Tep of the fluid flowing through the exhaust port 34 immediately before stopping the engine 12 (when normal control or non-ignition control is being executed as control of the engine 12) (the temperature of the fluid flowing through the first exhaust pipe section 35a) and a value estimated based on the outside temperature Tout are input.

Subsequently, as shown in equation (8), the temperature of the fluid containing the catalyst is determined using the temperature Tex of the first exhaust pipe portion 35a, the previously estimated temperature of the catalyst 37a (previous Tcat), and the convective temperature difference coefficient kdt. Tgci is estimated (step S310), and this routine ends. Here, for the convective temperature difference coefficient kdt, a value predetermined by experiment, analysis, etc. is used in consideration of the fact that fluid convection occurs within the first exhaust pipe portion 35a while the engine 12 is stopped.

Tgci=Tex＋(previous Tcat－Tex)・kdt (8)

When the temperature Tgci of the fluid containing the catalyst is estimated in this way, the amount of heat Qcat obtained by multiplying the previously estimated temperature of the catalyst 37a (previous Tcat) by a conversion coefficient, the amount of heat exchange between the catalyst 37a and the fluid containing the catalyst Hgci, The temperature Tcat of the catalyst 37a is estimated in consideration of the amount of heat exchange Hgco between the catalyst 37a and the catalyst output fluid and the total heat capacity Cg of the catalyst 37a. Here, the heat exchange amounts Hgci and Hgco are based on the previously estimated temperature of the catalyst 37a (previous Tcat) and the temperature Tgci of the fluid entering the catalyst.

Through experiments and analysis, the inventors have discovered that while the engine 12 is stopped, the temperature Tgci of the fluid entering the catalyst gradually approaches the temperature Tex of the first exhaust pipe section 35a having a large heat capacity, and that It has been found that natural convection of fluid occurs within the first exhaust pipe portion 35a when the temperature of the catalyst 37a is higher than the temperature Tex of the catalyst 35a. Therefore, by estimating the temperature Tcat of the catalyst 37a using equations (9) to (11), the temperature Tcat of the catalyst 37a can be estimated more appropriately. Note that the temperature Tcat2 of the purification device 38 is also related to the temperature Tex2 of the second exhaust pipe section 35b and the fluid inside the second exhaust pipe section 35b when the temperature of the catalyst 38a is higher than the temperature of the second exhaust pipe section 35b. It can be similarly estimated by taking into account natural convection, etc.

In the engine device 10 of the embodiment, the supercharger 40 is configured as a turbocharger in which a turbine 41 disposed in the exhaust pipe 35 and a compressor 42 disposed in the intake pipe 23 are connected via a connecting shaft 43. I took it as a thing. However, a compressor driven by the engine 12 or a motor may be configured as a supercharger disposed in the intake pipe 23. Alternatively, the supercharger 40 may not be provided.

In the embodiment, the engine device 10 is mounted on a general automobile or various hybrid automobiles. However, it may be mounted on a vehicle other than a car, or may be mounted on non-moving equipment such as construction equipment.

The correspondence between the main elements of the embodiments and the main elements of the invention described in the column of means for solving the problems will be explained. In the embodiment, the engine 12 corresponds to an "engine," the catalyst 37a corresponds to a "catalyst," and the electronic control unit 70 corresponds to a "control device."

The correspondence relationship between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem is that the example implements the invention described in the column of means for solving the problem. Since this is an example for specifically explaining a form for solving the problem, it is not intended to limit the elements of the invention described in the column of means for solving the problems. In other words, the interpretation of the invention described in the column of means for solving the problem should be based on the description in that column, and the examples are based on the description of the invention described in the column of means for solving the problem. This is just one specific example.

Although the embodiments of the present invention have been described above using examples, the present invention is not limited to these examples in any way, and may be modified in various forms without departing from the gist of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing industry of an engine device, etc.

Reference Signs List 10 engine device, 12 engine, 14 crankshaft, 14a crank position sensor, 22 air cleaner, 23 intake pipe, 23a air flow meter, 23b intake pressure sensor, 23c boost pressure sensor, 24 bypass pipe, 25 intercooler, 26 throttle valve, 26a throttle position sensor, 27 surge tank, 27a surge pressure sensor, 27b temperature sensor, 28 in-cylinder injection valve, 29 intake port, 29a intake valve, 30 combustion chamber, 31 spark plug, 32 piston, 34 exhaust port, 34a exhaust valve , 35 exhaust pipe, 35a first exhaust pipe section, 35b second exhaust pipe section, 35c third exhaust pipe section, 36 bypass pipe, 37, 38 purifier, 37a, 38a catalyst, 39a air-fuel ratio sensor, 39b oxygen sensor, 40 supercharger, 41 turbine, 42 compressor, 43 connection shaft, 44 waste gate valve, 45 blow-off valve, 70 electronic control unit, 71 atmospheric pressure sensor, 72 outside temperature sensor.

Claims (1)

an engine having a fuel injector and a spark plug;
a catalyst attached to an exhaust pipe connected to an exhaust port of the engine;
a control device that controls the engine;
An engine device comprising:
When the control device executes non-ignition control in which fuel is injected from the fuel injection valve without ignition by the spark plug as control of the engine, the control device controls the mist of fuel injected from the fuel injection valve. estimating the temperature of the fluid flowing through the exhaust port, taking into account the oxidation delay and assuming that part of the atomized fuel is combusted in the cylinders of the engine;
engine equipment.

Images