JP2021173176A - Engine device - Google Patents

Abstract

To estimate a temperature of fluid flowing through an exhaust port of an engine in a case of executing non-ignition control.SOLUTION: An engine device comprises an engine having a fuel injection valve and a spark plug, and a catalyst attached to an exhaust pipe connected to an exhaust port of the engine. When performing non-ignition control in which fuel is injected from the fuel injection valve without ignition by a spark plug as engine control, the engine device considers delay in atomization of the fuel injected from the fuel injection valve, and estimates a temperature of the fluid flowing through the exhaust port assuming that a part of the atomized fuel burns in the cylinder of the engine.SELECTED DRAWING: Figure 3

Description

The present invention relates to an engine device.

Conventionally, in this type of engine device, when the fuel cut condition of the engine is satisfied, the fuel cut is delayed when the temperature of the catalyst attached to the exhaust pipe connected to the exhaust port of the engine is higher than the threshold value. At the same time, it has been proposed to set the target air-fuel ratio during the delay period of the fuel cut to the lean side of the theoretical air-fuel ratio (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-191665

In such an engine device, the engine may be subjected to non-ignition control in which fuel is injected without ignition for warming up the catalyst, but in this case, the fluid (exhaust) flowing through the exhaust port of the engine. No method for estimating the temperature of the engine has been devised.

An object of the engine device of the present invention is to make it possible to estimate the temperature of a fluid flowing through an engine exhaust port when non-ignition control is being executed.

The engine device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The engine device of the present invention
Engines with fuel injection valves and spark plugs,
A catalyst attached to the exhaust pipe connected to the exhaust port of the engine,
The control device that controls the engine and
It is an engine device equipped with
When the control device executes non-ignition control in which fuel is injected from the fuel injection valve without ignition by the ignition plug as control of the engine, the mist of fuel injected from the fuel injection valve is executed. The temperature of the fluid flowing through the exhaust port is estimated assuming that a part of the atomized fuel burns in the cylinder of the engine while considering the delay in fuel injection.
The gist is that.

In the engine device of the present invention, when non-ignition control in which fuel is injected from the fuel injection valve without ignition by the ignition plug is executed as engine control, the atomization delay of the fuel injected from the fuel injection valve is executed. The temperature of the fluid flowing through the exhaust port is estimated assuming that a part of the atomized fuel burns in the cylinder of the engine. In this way, the temperature of the fluid flowing through the exhaust port when non-ignition control is being performed can be estimated. The inventors confirmed this by experiment and analysis.

In the engine device of the present invention, when the non-ignition control is being executed, the control device performs a smoothing process using a time constant on the injection amount injected from the fuel injection valve to atomize it. The amount of atomization is estimated, the amount of heat generated by the combustion of the atomized fuel is estimated based on the amount of atomization and the reaction rate of burning in the cylinder, and the exhaust port is set in consideration of the amount of heat generated. It may be used to estimate the temperature of the flowing fluid. In this way, the temperature of the fluid flowing through the exhaust port can be estimated more appropriately.

It is a block diagram which shows the outline of the structure of the engine device 10 as one Example of this invention. It is explanatory drawing which shows an example of the input / output signal of an electronic control unit 70. It is a flowchart which shows an example of the processing routine executed by the electronic control unit 70. It is explanatory drawing which shows an example of the time constant setting map. It is explanatory drawing which shows an example of the map for setting a heat receiving ratio. It is a flowchart which shows an example of the processing routine executed by the electronic control unit 70.

Next, a mode for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of an engine device 10 as an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of an input / output signal of the electronic control unit 70. The engine device 10 of the embodiment is mounted on a general automobile or various hybrid automobiles, and as shown in FIGS. 1 and 2, the engine 12, the supercharger 40, and the electronic control unit 70 as a control device To be equipped.

The engine 12 is configured as a multi-cylinder (for example, 4-cylinder, 6-cylinder, etc.) internal combustion engine that outputs power by four strokes of intake, compression, expansion, and exhaust using a hydrocarbon-based fuel such as gasoline or light oil. ing. The engine 12 sucks the air cleaned by the air cleaner 22 into the intake pipe 23 and passes it through the intercooler 25, the throttle valve 26, and the surge tank 27 in this order. Then, fuel is injected from the in-cylinder injection valve 28 attached to the combustion chamber 30 into the air sucked into the combustion chamber 30 through the intake port 29 to mix the air and the fuel, and the air is exploded by the electric spark from the spark plug 31. Burn. The intake port 29 is opened and closed by the intake valve 29a. The engine 12 converts the reciprocating motion of the piston 32 pushed down by the energy generated by such explosive combustion into the rotational motion of the crankshaft 14. The exhaust gas from the combustion chamber 30 is discharged to the exhaust pipe 35 connected to the exhaust port 34, and is discharged to the outside air through the purification devices 37 and 38 attached to the exhaust pipe 35. The exhaust port 34 is opened and closed by the exhaust valve 34a. The purification devices 37 and 38 have catalysts (three-way catalysts) 37a and 38a for purifying harmful components of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx). Hereinafter, the portion of the exhaust pipe 35 on the upstream side of the purification device 37, the portion between the purification devices 37 and 38, and the portion on the downstream side of the purification device 38 are referred to as "first exhaust pipe portion 35a" and "first exhaust pipe portion 35a", respectively. It is referred to as "2 exhaust pipe portion 35b" and "third exhaust pipe portion 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 arranged on the upstream side (first exhaust pipe portion 35a) of the purification device 37 of the exhaust pipe 35. The compressor 42 is arranged upstream of the intercooler 25 of the intake pipe 23 and is connected to the turbine 41 via a connecting shaft 43. Therefore, the compressor 42 is driven by the turbine 41. The wastegate valve 44 is provided in a bypass pipe 36 that connects the upstream side and the downstream side of the exhaust pipe 35 with respect to the turbine 41, and is controlled by the electronic control unit 70. The blow-off valve 45 is provided in a bypass pipe 24 that connects the upstream side and the downstream side of the intake pipe 23 with respect to the compressor 42, and is controlled by the electronic control unit 70.

In the supercharger 40, by adjusting the opening degree of the wastegate valve 44, the distribution ratio between the displacement flowing through the bypass pipe 36 and the displacement flowing through the turbine 41 is adjusted, and the rotational driving force of the turbine 41 is adjusted. Then, the amount of compressed air by the compressor 42 is adjusted, and the supercharging pressure (intake pressure) of the engine 12 is adjusted. Here, in detail, the distribution ratio is adjusted so that the smaller the opening degree of the wastegate valve 44, the smaller the displacement through the bypass pipe 36 and the larger the displacement through the turbine 41. When the wastegate valve 44 is fully opened, the engine 12 operates in the same manner as a naturally aspirated type engine without a supercharger 40.

Further, in the supercharger 40, when the pressure on the downstream side of the intake pipe 23 on the downstream side is higher than the pressure on the upstream side to some extent, the blow-off valve 45 is opened to cause a surplus on the downstream side of the compressor 42. The pressure can be released. The blow-off valve 45 is configured as a check valve that opens when the pressure on the downstream side of the compressor 42 of the intake pipe 23 becomes higher than the pressure on the upstream side to some extent, instead of the valve controlled by the electronic control unit 70. It may be done.

The electronic control unit 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, a non-volatile 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.

The signals input to the electronic control unit 70 include, for example, a crank angle θcr from the crank position sensor 14a that detects the rotational position of the crankshaft 14 of the engine 12, and a 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 degree of the throttle valve 26. Cam position θca 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 cam shaft that opens and closes the exhaust valve 34a can also be mentioned. The intake air amount Qa from the air flow meter 23a installed on the upstream side of the compressor 42 of the intake pipe 23, the intake pressure Pin from the intake pressure sensor 23b installed on the upstream side of the compressor 42 of the intake pipe 23, and the intake air. The supercharging pressure Pc from the supercharging 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 (first exhaust pipe portion 35a) of the purification device 37 of the exhaust pipe 35, and between the purification devices 37 and 38 of the exhaust pipe 35 (second exhaust pipe portion). The oxygen signal O2 from the oxygen sensor 39b attached to 35b) can also be mentioned. The atmospheric pressure Pout from the atmospheric pressure sensor 71 and the outside air temperature Tout from the outside air temperature sensor 72 can also be mentioned.

Various control signals are output from the electronic control unit 70 via the output port. Examples of the signal 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 has a load factor (air actually sucked in one cycle with respect to the stroke volume per 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. 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. In normal control, intake air amount control that controls the opening degree of the throttle valve 26 based on the required load factor KL * of the engine 12, fuel injection control that controls the fuel injection amount from the in-cylinder injection valve 28, and a spark plug Ignition control for controlling the ignition timing of 31 and supercharging control for controlling the opening degree of the wastegate valve 44 are performed. As described above, when the wastegate valve 44 is fully opened, the engine 12 operates in the same manner as a naturally aspirated engine without a supercharger 40.

Further, in the engine device 10 of the embodiment, the electronic control unit 70 executes non-ignition control as control of the engine 12 when warming up of the catalyst 37a of the purification device 37 is required when the fuel cut condition is satisfied. do. In the non-ignition control, a very small amount of fuel is injected from the in-cylinder injection valve 28 without performing ignition control or supercharging control (without igniting by the spark plug 31 and opening the wastegate valve 44). As the fuel cut condition, for example, a condition in which the accelerator is turned off in a vehicle on which the engine device 10 is mounted is used. The warm-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 the non-ignition control is being executed, at least a part of the fuel injected from the in-cylinder injection valve 28 is atomized with a delay, and a part of the atomized fuel is in the combustion chamber 30 near the top dead center of the compression stroke. At the same time, at least a part of the atomized fuel is burned (reacted) by the catalyst 37a while being burned (reacted) by the low temperature oxidation reaction. The inventors confirmed this by experiment and analysis. In the embodiment, for the sake of simplicity, it is assumed that a part of the atomized fuel is burned in the combustion chamber 30 and the remainder is burned in the catalyst 37a.

Next, the operation of the engine device 10 configured in this way will be described. In particular, a process of estimating the temperature Tep of the fluid (exhaust) flowing through the exhaust port 34 and the temperature Tcat of the catalyst 37a of the purification device 37 when the non-ignition control is executed as the control of the engine 12 will be described. In the embodiment, the temperature of the confluence portion merging from the exhaust port 34 of each cylinder is estimated as the temperature Tip of the fluid flowing through the exhaust port 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 while fuel injection is being performed from the in-cylinder injection valve 28 (when normal control or non-ignition control is being 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 the non-ignition control is executed as the control of the engine 12 (step S100). When it is determined that the non-ignition control is executed as the control of the engine 12, the rotation speed Ne of the engine 12, the load factor KL, the flow velocity Vep of the fluid (exhaust) flowing through the exhaust port 34, and the non-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 rotation speed Ne, a value calculated based on the crank angle θcr from the crank position sensor 14a is input. For the load factor KL, a value calculated based on the intake air amount Qa from the air flow meter 23a and the rotation speed Ne is input. For 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. For the non-ignition total injection amount Qfcyc, a value calculated as the sum of the fuel injection amounts Qf (i) of each cylinder when the non-ignition injection control is being executed is input.

Subsequently, the in-cylinder injection valve 28 when the non-ignition control is executed is based on the temperature (previous Tgci) of the catalyst-filled fluid input (inflowing) to the catalyst 37a of the purification device 37 estimated last time. The time constant τ for simulating the delay until the fuel injected from is atomized is estimated (step S120). Then, the total non-ignition injection amount Qfcyc of one cycle is annealed using the time constant τ, and the total atomization amount Qatm atomized in all the combustion chambers 30 of the total non-ignition injection amount Qfcyc (each). The total amount of atomization atomized in the combustion chamber 30 of the cylinder) is estimated (step S130). In the embodiment, as shown in the equation (1), the total atomization amount Qatm is estimated by dividing the non-ignition total injection amount Qfcyc in one cycle by the time constant τ. In equation (1) and each of the following equations, the units are shown in square brackets.

Qatm = Qfcyc / τ (1)

Here, the time constant τ is set by applying the temperature of the previous catalyst-containing fluid (previous Tgci) to the time constant setting map in the embodiment. The time constant setting map is predetermined by experiments and analysis as the relationship between the temperature of the previous catalyst-filled fluid (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 as the temperature of the previous catalyst-containing fluid (previous Tgci) is higher in the range larger than the value 1. This is because the higher the temperature of the previous catalyst-filled fluid (previous Tgci), the higher the temperature inside the combustion chamber 30, and the fuel injected from the in-cylinder injection valve 28 is likely to be atomized in a short time.

When the total atomization amount Qatm atomized in the combustion chamber 30 is estimated in this way, as shown in the equation (2), the total combustion amount Qcylcmb is estimated as the product of the total atomization amount Qatm and the reaction ratio Rcyl (step). S160). Here, the reaction ratio Rcyl and the total combustion amount Qcylcmb are the reaction ratio and the total combustion amount (each cylinder) burned by the low temperature oxidation reaction in all the combustion chambers 30 of the atomized fuel (total atomization amount Qatm), respectively. The total amount of combustion burned in the combustion chamber 30 of the above). As the reaction ratio Rcyl, a value predetermined by experiment or analysis is used in the examples.

Qcylcmb = Qatm ・ Rcyl (2)

Subsequently, as shown in the 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 ΔTylcal (step S170). ). Here, the combustion calorific value ΔQcycle and the temperature rise amount ΔTcycle are the unit masses when a part of the atomized fuel is burned (reacted) by a low temperature oxidation reaction in the combustion chamber 30 near the top dead center of the compression stroke, respectively. The amount of heat generated per unit and the total amount of heat generated (the total amount of heat generated by combustion in the combustion chamber 30 of each cylinder). The combustion calorific value ΔQcylcal may be a constant determined in advance by experiment or analysis, or may be determined based on the ignition timing by 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 by experiment or analysis, or may be determined based on the alcohol concentration of the fuel detected by an alcohol concentration sensor (not shown). May be good.

ΔTcylcal = Qcylcmb ・ ΔQcylcal / κg (3)

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

Here, the heat receiving ratio Rhr is set by applying the flow velocity Vep of the fluid flowing through the exhaust port 34 to the heat receiving ratio setting map in the embodiment. The heat receiving ratio setting map is predetermined by experiments and analyzes as the relationship between the flow velocity Vep of the fluid flowing through the exhaust port 34 and the heat receiving 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 receiving ratio setting map. As shown in the figure, the heat receiving ratio Rhr is set to be smaller as the flow velocity Vep of the fluid flowing through the exhaust port 34 is larger in the range larger than the value 0 and smaller than the value 1. This is because the larger the flow velocity Vep of the fluid flowing through the exhaust port 34, the more difficult it is for the heat generated by combustion in the combustion chamber 30 to be transferred to the fluid flowing through the exhaust port 34.

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

Tep = Tepbs ＋ ΔTcylcal ・ Rhr (4)

In the embodiment, when the non-ignition control is executed, at least a part of the fuel injected from the in-cylinder injection valve 28 is atomized with a delay, and a part of the atomized fuel is cooled in the combustion chamber 30. In consideration of combustion due to the oxidation reaction, specifically, the temperature Tep of the fluid flowing through the exhaust port 34 is estimated in consideration of the temperature rise amount ΔTylcal estimated in step S170. As a result, the temperature tip of the fluid flowing through the exhaust port 34 can be estimated more appropriately than the temperature tip of the fluid flowing through the exhaust port 34 without considering the temperature rise amount ΔTcyclel.

When the temperature Tep of the fluid flowing through the exhaust port 34 is estimated 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 tip of the fluid flowing through the exhaust port 34, the catalyst-filled fluid takes into consideration the heat transfer amount Hge between the fluid (exhaust) flowing through the first exhaust pipe portion 35a and the first exhaust pipe portion 35a. The temperature Tgci was estimated. The 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 portion 35a) and the temperature Tex of the first exhaust pipe portion 35a increases. ..

When the temperature Tgci of the fluid containing the catalyst is estimated in this way, as shown in the formula (5), the total atomization amount Qatm estimated in step S130 and the value (1-Rcyl) obtained by subtracting the above-mentioned reaction ratio Rcyl from the value 1 are obtained. As a product, the total combustion amount (fuel amount) Qcatcmb is estimated (step S220). Here, the total combustion amount Qcatcmb is the total combustion amount of the atomized fuel (total atomization amount Qatm) burned by the catalyst 37a.

Qcatcmb = Qatm ・ (1-Rcyl) (5)

Subsequently, as shown in the 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 and the total calorific value per unit mass when a part of the atomized fuel is burned (reacted) by the catalyst 37a, respectively. The combustion calorific value ΔQcatcal may be a constant determined in advance by experiment or analysis, or may be determined based on the ignition timing by the spark plug 31 or the like.

Qcatcal = Qcatcmb ・ ΔQcatcal (6)

Subsequently, as shown in the formula (7), the sum of the value obtained by multiplying the temperature Tgci of the catalyst-containing fluid estimated in step S210 by the heat capacity Cg of the catalyst-containing fluid and the total calorific value Qcatcal estimated in step S230 is used. The calorific value Qgcat of the catalyst-filled fluid input (inflowed) to the catalyst 37a is estimated (step S240), and the temperature of the catalyst 37a estimated last time (previous Tcat) and the calorific value Qgcat of the catalyst-filled fluid are estimated. The temperature Tcat is estimated (step S250), and this routine is terminated. Here, the heat capacity Cg of the catalyst-containing fluid is preset by, for example, an experiment or an analysis.

Qgcat = Tgci ・ Cg ＋ Qgcatcal (7)

The temperature Tcat of the catalyst 37a is, for example, the calorific value Qcat obtained by multiplying the previously estimated temperature of the catalyst 37a (previous Tcat) by a conversion coefficient, the calorific value Qgcat of the catalyst-containing fluid, and between the catalyst 37a and the catalyst-containing fluid. It can be estimated in consideration of the heat exchange amount Hgci, the heat exchange amount Hgco between the catalyst 37a and the catalyst discharge 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) (heat amount Qcat) and the heat amount Qgcat of the catalyst-containing fluid.

In the embodiment, as described above, the temperature Tep of the fluid flowing through the exhaust port 34 can be estimated more appropriately. Therefore, based on the temperature Tep of the fluid flowing through the exhaust port 34, the temperature Tgci of the fluid containing the catalyst or 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 Tgci of the catalyst input fluid and the temperature Tgco of the catalyst output fluid (passing through the catalyst 37a) output from the catalyst 37a based on the temperature Tcat of the catalyst 37a, the second exhaust Considering the heat transfer amount Hge2 between the fluid (exhaust) flowing through the pipe portion 35b and the second exhaust pipe portion 35b, the temperature Tgci2 of the second catalyst-containing fluid input (inflowing) to the catalyst 38a is estimated, and the second 2 The temperature Tcat2 of the catalyst 38a is estimated based on the temperature Tgci2 of the catalyst-containing fluid. The heat transfer amount Hge2 increases as the temperature difference between the temperature Tgco of the catalyst discharge fluid (the temperature of the fluid flowing through the second exhaust pipe portion 35b) and the temperature Tex2 of the second exhaust pipe portion 35b increases.

When it is determined in step S100 that the non-ignition control is not 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 rate Ne and the load factor KL of the engine 12 are determined. , Data such as the flow velocity Vep of the fluid (exhaust) flowing through the exhaust port 34 is input (step S140). Subsequently, a value 0 is set in the total atomization amount Qatm based on the non-ignition control (step S150), and the processes after step S160 are executed. In this case, since the total atomization amount Qatm is a value 0, the total combustion amount Qcylcmb becomes a value 0 in step S160, and the temperature rise amount ΔTylcal becomes a value 0 in step S170. Then, in step S200, the second term on the right side of the equation (4) becomes a value 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 above-described embodiment, at least a part of the fuel injected from the in-cylinder injection valve 28 is atomized with a delay and a part of the atomized fuel when the non-ignition control is executed. Specifically, the temperature Tep of the fluid flowing through the exhaust port 34 is estimated in consideration of the fact that the fuel burns in the combustion chamber 30 due to the low temperature oxidation reaction, and specifically, in consideration of the temperature rise amount ΔTcycle estimated in step S170. As a result, the temperature tip of the fluid flowing through the exhaust port 34 can be estimated more appropriately than the temperature tip of the fluid flowing through the exhaust port 34 without considering the temperature rise amount ΔTcyclel.

In the engine device 10 of the embodiment, a process of estimating the temperature Tep of the fluid (exhaust) flowing through the exhaust port 34 and the temperature Tcat of the catalyst 37a of the purification device 37 when the non-ignition control is executed as the control of the engine 12. Was explained. On the other hand, when the engine 12 is stopped, the electronic control unit 70 estimates the temperature Tcat of the catalyst 37a by the processing routine of 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 unit 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 the engine 12 is stopped (when normal control or non-ignition control is executed as the control of the engine 12). (The temperature of the fluid flowing through the first exhaust pipe portion 35a) and the value estimated based on the outside air temperature Tout are input.

Subsequently, as shown in the equation (8), the temperature of the fluid containing the catalyst is used by using the temperature Tex of the first exhaust pipe portion 35a, the temperature of the catalyst 37a estimated last time (previous Tcat), and the convective temperature difference coefficient kdt. Tgci is estimated (step S310), and this routine is terminated. Here, as the convection temperature difference coefficient kdt, a value predetermined by experiments or analysis is used in consideration of the convection of the fluid in 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 catalyst-containing fluid is estimated in this way, the calorific value Qcat obtained by multiplying the previously estimated temperature of the catalyst 37a (previous Tcat) by the conversion coefficient, and the heat exchange amount Hgci between the catalyst 37a and the catalyst-containing fluid, The temperature Tcat of the catalyst 37a is estimated in consideration of the heat exchange amount Hgco between the catalyst 37a and the catalyst outflow 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 catalyst-containing fluid.

According to experiments and analyzes, the inventors have found that the temperature Tgci of the catalyst-containing fluid gradually approaches the temperature Tex of the first exhaust pipe portion 35a having a large heat capacity while the engine 12 is stopped, and that the first exhaust pipe portion It has been found that when the temperature of the catalyst 37a is higher than the temperature Tex of 35a, natural convection of the fluid occurs in the first exhaust pipe portion 35a. Therefore, by estimating the temperature Tcat of the catalyst 37a by the formulas (9) to (11), the temperature Tcat of the catalyst 37a can be estimated more appropriately. Regarding the temperature Tcat2 of the purification device 38, the temperature Tex2 of the second exhaust pipe portion 35b and the fluid in the second exhaust pipe portion 35b when the temperature of the catalyst 38a is higher than the temperature of the second exhaust pipe portion 35b. It can be estimated in the same way in consideration of the natural convection of.

In the engine device 10 of the embodiment, the supercharger 40 is configured as a turbocharger in which a turbine 41 arranged in an exhaust pipe 35 and a compressor 42 arranged in an intake pipe 23 are connected via a connecting shaft 43. I made it. However, the compressor driven by the engine 12 or the motor may be configured as a supercharger arranged in the intake pipe 23. Further, 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 an automobile, or may be mounted on non-moving equipment such as construction equipment.

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

Regarding the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problem in the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to examples, the present invention is not limited to these examples, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the manufacturing industry of engine devices and the like.

10 engine unit, 12 engine, 14 crank shaft, 14a crank position sensor, 22 air cleaner, 23 intake pipe, 23a air flow meter, 23b intake pressure sensor, 23c supercharging 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 ignition plug, 32 piston, 34 exhaust port, 34a exhaust valve , 35 exhaust pipe, 35a first exhaust pipe part, 35b second exhaust pipe part, 35c third exhaust pipe part, 36 bypass pipe, 37,38 purification device, 37a, 38a catalyst, 39a air fuel ratio sensor, 39b oxygen sensor, 40 turbocharger, 41 turbine, 42 compressor, 43 connecting shaft, 44 waste gate valve, 45 blow-off valve, 70 electronic control unit, 71 atmospheric pressure sensor, 72 outside temperature sensor.

Claims (1)

Engines with fuel injection valves and spark plugs,
A catalyst attached to the exhaust pipe connected to the exhaust port of the engine,
The control device that controls the engine and
It is an engine device equipped with
When the control device executes non-ignition control in which fuel is injected from the fuel injection valve without ignition by the ignition plug as control of the engine, the mist of fuel injected from the fuel injection valve is executed. The temperature of the fluid flowing through the exhaust port is estimated assuming that a part of the atomized fuel burns in the cylinder of the engine while considering the delay in fuel injection.
Engine device.

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