Engine device

Abstract

To more appropriately estimate a temperature of a purification catalyst in a purification device that purifies exhaust gas from an engine.SOLUTION: An engine device determines a temperature correction term due to scavenging on the basis of an engine speed, a port injection ratio that is a ratio of a fuel injection amount from a port injection valve to a total fuel injection amount from a port injection valve and an in-cylinder injection valve, and an atmospheric pressure; and estimates a temperature of a purification catalyst in a purification device that purifies exhaust gas from an engine by adding a correction including at least the temperature correction term due to scavenging to a basic estimation temperature based on the engine speed and a load. Consequently, it is possible to more appropriately estimate the temperature of the purification catalyst.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an engine device, and more particularly to an engine device for estimating the temperature of a purification catalyst in a purification device that purifies exhaust gas from an engine.

Background Art

[0002] Conventionally, as this type of engine device, there has been proposed one that calculates a corrected catalyst temperature in consideration of a catalyst temperature rise based on scavenging with respect to a catalyst bed temperature estimated based on an engine speed and an engine load (see, for example, Patent Document 1). This engine device compares the obtained corrected catalyst temperature with a set temperature, and when the corrected catalyst temperature is higher than the set temperature, performs control to prevent the temperature rise of the catalyst bed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described engine device, when an engine having a supercharger is provided, there are cases where the catalyst temperature cannot be appropriately estimated. In highlands where the atmospheric pressure is low, the back pressure is low, so the amount of air flowing from the intake pipe to the exhaust pipe due to scavenging (scavenging amount) increases, and a catalyst temperature rise based on inappropriate scavenging is calculated, making it impossible to obtain an appropriate corrected catalyst temperature. Further, in an engine equipped with a port injection valve and an in-cylinder injection valve, if the ratio of fuel injection from the port injection valve during scavenging is different, the catalyst temperature rise based on scavenging also becomes different.

[0005] The main object of the engine device of the present invention is to more appropriately estimate the temperature of a purification catalyst in a purification device that purifies exhaust gas from an engine.

Means for Solving the Problem

[0006] The engine device of the present invention has adopted the following means in order to achieve the above main object.

[0007] The engine device of the present invention is an engine equipped with a supercharger and having a port injection valve and an in-cylinder injection valve, a purification device having a purification catalyst for purifying the exhaust gas from the engine, and a control device for estimating the temperature of the purification catalyst by adding a correction including a temperature correction term due to scavenging to a basic estimated temperature based on the rotational speed and load of the engine. The engine device is characterized in that the control device determines the temperature correction term due to scavenging based on the rotational speed of the engine, the port injection ratio which is the ratio of the fuel injection amount from the port injection valve to the total fuel injection amount from the port injection valve and the in-cylinder injection valve, and the atmospheric pressure.

[0008] In the engine device of the present invention, the temperature of the purification catalyst in the purification device for purifying the exhaust gas from the engine is estimated by adding a correction including a temperature correction term due to scavenging to a basic estimated temperature based on the rotational speed and load of the engine. At this time, the temperature correction term due to scavenging is determined based on the rotational speed of the engine, the port injection ratio which is the ratio of the fuel injection amount from the port injection valve to the total fuel injection amount from the port injection valve and the in-cylinder injection valve, and the atmospheric pressure. Since the temperature correction term due to scavenging is determined based on the atmospheric pressure, the temperature correction term due to scavenging can be obtained more appropriately even in a highland with a low atmospheric pressure, and the temperature of the purification catalyst can be estimated more appropriately. Also, since the temperature correction term due to scavenging is determined based on the port injection ratio, the temperature correction term due to scavenging corresponding to the port injection ratio can be obtained, and the temperature of the purification catalyst can be estimated more appropriately. As a result, the temperature of the purification catalyst can be estimated more appropriately.

[0009] ​In the engine device of the present invention, the control device calculates the increase in temperature per unit scavenging rate such that it becomes larger when the engine speed is high than when it is low, becomes larger when the port injection ratio is high than when it is low, and becomes larger when the atmospheric pressure is low than when it is high. Then, the temperature correction term due to scavenging is determined by multiplying the difference between the current scavenging rate and the steady-state scavenging rate by the increase in temperature per unit scavenging rate. This enables more appropriate acquisition of the temperature correction term due to scavenging and more accurate estimation of the temperature of the purification catalyst. The reason for making the increase in temperature per unit scavenging rate larger when the engine speed is high than when it is low is based on the fact that the scavenging amount per unit time is larger when the engine speed is high than when it is low. The reason for making the increase in temperature per unit scavenging rate larger when the port injection ratio is high than when it is low is based on the fact that the amount of unburned fuel in the air flowing into the purification device is larger when the port injection ratio is high than when it is low. The reason for making the increase in temperature per unit scavenging rate larger when the atmospheric pressure is low than when it is high is based on the fact that the back pressure is lower and the scavenging amount is larger when the atmospheric pressure is low than when it is high. The scavenging rate is the ratio of the scavenging amount to the amount of air passing through the intake valve. The steady-state scavenging rate is the scavenging rate at a predetermined engine speed, a predetermined port injection ratio, and a predetermined atmospheric pressure.

[0010] As the increase in temperature per unit scavenging rate, the increase in temperature per unit scavenging rate obtained by applying the engine speed, port injection ratio, and atmospheric pressure to a map in which the relationship between the engine speed, port injection ratio, atmospheric pressure, and the increase in temperature per unit scavenging rate has been previously determined can be used. This allows for more rapid and appropriate acquisition of the increase in temperature per unit scavenging rate.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0012] Next, the mode for carrying out the present invention will be described using examples.

Examples

[0013] FIG. 1 is a configuration diagram showing an outline of the configuration of the 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 mounted on a general vehicle that runs using the power from the engine 12 or various hybrid vehicles equipped with a motor in addition to the engine 12. As shown in FIGS. 1 and 2, the engine device 10 includes an engine 12, a supercharger 40, a fuel supply device 16, and an electronic control unit 70.

[0014] The engine 12 is configured as an internal combustion engine that outputs power using fuel such as gasoline or light oil supplied from the fuel tank 11. This engine 12 has a port injection valve 28 that injects fuel into the intake port, an in-cylinder injection valve 29 that injects fuel into the combustion chamber 31, and a spark plug 32. The in-cylinder injection valve 29 is disposed substantially at the center of the top of the combustion chamber 31 and injects fuel in a spray form. The spark plug 32 is disposed in the vicinity of the in-cylinder injection valve 29 so as to be able to ignite the fuel sprayed in a spray form from the in-cylinder injection valve 29.

[0015] The engine 12 is capable of operating in either a port injection mode, a direct injection mode, or a combined injection mode by having a port injection valve 28 and a direct injection valve 29. In the embodiment, the ratio of the fuel injection amount by the port injection valve 28 to the total fuel injection amount is defined as the port injection ratio Rp (0 ≦ Rp ≦ 1). The port injection mode is the case where the port injection ratio Rp has a value of 1, the direct injection mode is the case where the port injection ratio Rp has a value of 0, and in the combined injection mode, the port injection ratio Rp is greater than 0 and less than 1 (0 < Rp < 1).

[0016] In the port injection mode, air cleaned by the air cleaner 22 is inhaled into the intake pipe 23 and passed through the intercooler 25, throttle valve 26, and surge tank 27 in that order. Fuel is injected from the port injection valve 28 on the downstream side of the surge tank 27 in the intake pipe 23, and the air and fuel are mixed. This air-fuel mixture is inhaled into the combustion chamber 31 through the intake valve 30 and explosively combusted by an electric spark from the spark plug 32. Then, the reciprocating motion of the piston 33 pushed down by the energy of the explosive combustion is converted into the rotational motion of the crankshaft 14. In the direct injection mode, air is inhaled into the combustion chamber 31 in the same manner as in the port injection mode, and fuel is injected one or more times from the direct injection valve 29 during the intake stroke, compression stroke, or expansion stroke, and explosively combusted by an electric spark from the spark plug 32 to obtain the rotational motion of the crankshaft 14. Particularly when fuel is injected during the expansion stroke, the fuel injection from the direct injection valve 29 and the ignition by the spark plug 32 are synchronized during the expansion stroke so that the spray-like fuel injected from the direct injection valve 29 can be ignited. In the combined injection mode, fuel is injected from the port injection valve 28 when air is inhaled into the combustion chamber 31, and fuel is injected one or more times from the direct injection valve 29 during the intake stroke, compression stroke, or expansion stroke, and explosively combusted by an electric spark from the spark plug 32 to obtain the rotational motion of the crankshaft 14.

[0017] The exhaust gas discharged from the combustion chamber 31 to the exhaust pipe 35 through the exhaust valve 34 is discharged to the outside air through a purification device 37 having a catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). The crankshaft 14 is attached with a starter (not shown) for cranking the engine 12 and an alternator 48 that generates electricity by the power of the engine 12. The alternator 48 supplies the generated electricity to a power line that supplies power from a battery (not shown) to a fan motor 38d, a water pump 38e, etc. of the engine cooling system 38.

[0018] The fuel supply device 16 includes a fuel tank 11, a feed pump 11p, a low-pressure supply pipe 17, a high-pressure pump 18, and a high-pressure supply pipe 19. The fuel from the fuel tank 11 is pumped by the feed pump 11p and supplied to the port injection valve 28 via the low-pressure supply pipe 17. The feed pump 11p is configured as an electric pump that operates by receiving power from a battery (not shown) and is disposed in the fuel tank 11. Although not shown, a check valve that allows the flow of fuel in the direction from the feed pump 11p side to the port injection valve 28 side and restricts the reverse flow of fuel is also attached to the low-pressure supply pipe 17. Further, the fuel from the low-pressure supply pipe 17 is pumped by the high-pressure pump 18 and supplied to the in-cylinder injection valve 29 via the high-pressure supply pipe 19. The high-pressure pump 18 is configured as a pump that is driven by the power from the engine 12 (in the embodiment, the rotation of the intake camshaft that opens and closes the intake valve 30) and is disposed in the engine 12. The high-pressure pump 18 has an electromagnetic valve 18a that is connected to its suction port and opens and closes when pressurizing the fuel, a check valve 18b that is connected to its discharge port and restricts the reverse flow of fuel and maintains the fuel pressure in the high-pressure supply pipe 19, and a plunger 18c that operates by the rotation of the engine 12 (the rotation of the intake camshaft). When the electromagnetic valve 18a is opened during the operation of the engine 12, the fuel in the low-pressure supply pipe 17 is inhaled, and when the electromagnetic valve 18a is closed, the fuel compressed by the plunger 18c is intermittently fed into the high-pressure supply pipe 19 via the check valve 18b, thereby pressurizing the fuel supplied to the high-pressure supply pipe 19. When the high-pressure pump 18 is driven, the fuel pressure in the low-pressure supply pipe 17 and the fuel pressure in the high-pressure supply pipe 19 (the pressure of the fuel) pulsate according to the rotation of the engine 12 (the rotation of the intake camshaft).

[0019] The engine 12 is provided with an engine cooling system 38 that cools the engine 12 with a heat exchange medium (such as cooling water). The engine cooling system 38 includes a circulation passage 38a that circulates the heat exchange medium between a water jacket (not shown) of the engine 12 and a radiator 38b. A fan 38c driven by a fan motor 38d is attached to the radiator 38b, and the internal heat exchange medium (such as water) is cooled by the outside air. A water pump 38e for circulating the heat exchange medium is attached to the circulation passage 38a.

[0020] The supercharger 40 is configured as a turbocharger and includes a compressor 41, a turbine 42, a rotating shaft 43, a wastegate valve 44, and a blow-off valve 45. The compressor 41 is disposed upstream of the intercooler 25 in the intake pipe 23. The turbine 42 is disposed upstream of the purification device 37 in the exhaust pipe 35. The rotating shaft 43 connects the compressor 41 and the turbine 42. The wastegate valve 44 is provided in a bypass pipe 36 that connects the upstream side and the downstream side of the turbine 42 in the exhaust pipe 35 and is controlled by an 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 compressor 41 in the intake pipe 23 and is controlled by the electronic control unit 70.

[0021] In this supercharger 40, by adjusting the opening degree of the wastegate valve 44, the distribution ratio between the exhaust gas volume flowing through the bypass pipe 36 and the exhaust gas volume flowing through the turbine 42 is adjusted, the rotational driving force of the turbine 42 is adjusted, the amount of compressed air by the compressor 41 is adjusted, and the supercharging pressure (intake pressure) of the engine 12 is adjusted. Here, specifically, the smaller the opening degree of the wastegate valve 44, the less the exhaust gas volume flowing through the bypass pipe 36 and the more the exhaust gas volume flowing through the turbine 42 are adjusted. Note that when the wastegate valve 44 is fully open, the engine 12 can operate in the same manner as a naturally aspirated engine without a supercharger 40.

[0022] Also, in the supercharger 40, when the pressure on the downstream side of the compressor 41 in the intake pipe 23 is somewhat higher than the pressure on the upstream side, the blow-off valve 45 can be opened to release the excess pressure on the downstream side of the compressor 41. Note that the blow-off valve 45 may be configured as a check valve that opens when the pressure on the downstream side of the compressor 41 in the intake pipe 23 becomes somewhat higher than the pressure on the upstream side, instead of a valve controlled by the electronic control unit 70.

[0023] The electronic control unit 70 is configured as a microprocessor centered around a CPU, and in addition to the CPU, it includes a ROM that stores the processing program, a RAM that temporarily stores data, a non-volatile flash memory that stores and holds data, an input / output port, and a communication port. Signals from various sensors are input into the electronic control unit 70 via the input port.

[0024] Examples of signals input to the electronic control unit 70 include the tank internal pressure Ptnk from the internal pressure sensor 11a that detects the pressure in the fuel tank 11, the crank angle θcr from the crank position sensor 14a that detects the rotational position of the crankshaft 14 of the engine 12, the coolant temperature Tw of the engine 12 from the coolant temperature sensor 38f, and the throttle opening TH from the throttle position sensor 26a that detects the opening of the throttle valve 26. The cam position θca from a cam position sensor (not shown) that detects the rotational positions of the intake camshaft that opens and closes the intake valve 30 and the exhaust camshaft that opens and closes the exhaust valve 34 can also be included. The intake air amount Qa from the air flow meter 23a attached upstream of the compressor 41 in the intake pipe 23, the intake air temperature Tin from the intake air temperature sensor 23t attached upstream of the compressor 41 in the intake pipe 23, the intake air pressure (pressure before the compressor) Pin from the intake air pressure sensor 23b attached upstream of the compressor 41 in the intake pipe 23, and the supercharging pressure Pc from the supercharging pressure sensor 23c attached between the compressor 41 and the intercooler 25 in the intake pipe 23 can also be included. The surge pressure (pressure after the throttle) 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 included. The low-pressure fuel injection pressure Pfp from the fuel injection pressure sensor 28a that detects the fuel injection pressure of the fuel supplied to the port injection valve 28 and the high-pressure fuel injection pressure Pfd from the fuel injection pressure sensor 29a that detects the fuel injection pressure of the fuel supplied to the in-cylinder injection valve 29 can also be included. The front air-fuel ratio AF1 from the front air-fuel ratio sensor 35a attached upstream of the purification device 37 in the exhaust pipe 35 and the rear air-fuel ratio AF2 from the rear air-fuel ratio sensor 35b attached downstream of the purification device 37 in the exhaust pipe 35 can also be included. Also, the atmospheric pressure Pa from the atmospheric pressure sensor 72 can be included.

[0025] From the electronic control unit 70, various control signals are output via the output ports. Examples of signals output from the electronic control unit 70 include a control signal to the alternator 15, a control signal to the throttle valve 26, a control signal to the port injection valve 28, a control signal to the in-cylinder injection valve 29, and a control signal to the ignition plug 32. Also included are drive signals to the fan motor 38d and the water pump 38e of the engine cooling device 38, and drive signals to the fan motor 39d and the circulation pump 39e of the intercooler cooling device 39. Control signals to the wastegate valve 44, the blow-off valve 45, and the electromagnetic valve 18a can also be cited.

[0026] The electronic control unit 70 calculates the engine speed Ne and the load factor KL (the ratio of the volume of air actually inhaled per cycle to the stroke volume per cycle of the engine 12) of the engine 12. The engine speed Ne is calculated based on the crank angle θcr from the crank position sensor 14a. The load factor KL is calculated based on the intake air amount Qa from the air flow meter 23a and the engine speed Ne.

[0027] In the engine device 10 of the thus configured embodiment, the electronic control unit 70 performs intake air amount control for controlling the opening degree of the throttle valve 26, fuel injection control for controlling the fuel injection amount from the in-cylinder injection valve 28, ignition control for controlling the ignition timing of the ignition plug 31, supercharging control for controlling the opening degree of the wastegate valve 44, fuel pressure control of the high-pressure supply pipe 19 by opening and closing the electromagnetic valve 18a, etc., based on the required load factor KL* of the engine 12.

[0028] Next, the operation of the engine device 10 of the embodiment, particularly the operation when estimating the temperature Tc of the catalyst of the purification device 37, will be described. The estimated catalyst temperature Tc is compared with a threshold value Tref determined in advance assuming a functional degradation, and when the catalyst temperature Tc is equal to or higher than the threshold value Tref, a fuel increase amount for increasing the fuel injection amount is performed to cool the catalyst bed. FIG. 3 is a flowchart showing an example of the catalyst temperature estimation process executed by the electronic control unit 70. This catalyst temperature estimation process is repeatedly executed every predetermined time.

[0029] When the catalyst temperature estimation process is executed, the electronic control unit 70 first inputs data necessary for estimating the catalyst temperature Tc, such as the engine speed Ne of the engine 12, the load factor KL (engine load), the port injection ratio Rp, the atmospheric pressure Pa, and the scavenging ratio Sc (step S100).

[0030] Subsequently, a basic catalyst temperature Tcb is estimated based on the engine speed Ne and the load factor KL (engine load) of the engine 12 (step S110). In the embodiment, the relationship between the engine speed Ne and the load factor KL (engine load) of the engine 12 and the basic catalyst temperature Tcb is determined in advance by experiments or the like and stored as a basic catalyst temperature estimation map. When the engine speed Ne and the load factor KL (engine load) of the engine 12 are given, the corresponding basic catalyst temperature Tcb is derived from the map for estimation. The basic catalyst temperature Tcb is estimated to be higher as the engine speed Ne of the engine 12 is higher and as the load factor KL (engine load) is higher. This is based on the fact that as the engine speed Ne of the engine 12 increases, the exhaust gas volume per unit time increases, raising the catalyst temperature Tc, and as the load factor KL (engine load) increases, the energy amount per unit time due to the explosion combustion of the engine 12 increases, raising the catalyst temperature Tc.

[0031] Next, the temperature rise per unit scavenging ratio Tsp is set based on the engine speed Ne, port injection ratio Rp, and atmospheric pressure Pa of the engine 12 (step S120). Here, the scavenging ratio is the ratio of the scavenging amount to the amount of air passing through the intake valve. In the embodiment, the relationship between the engine speed Ne, port injection ratio Rp, atmospheric pressure Pa, and temperature rise per unit scavenging ratio Tsp of the engine 12 is obtained in advance through experiments or the like and stored as a map for setting the temperature rise per unit scavenging ratio. When the engine speed Ne, port injection ratio Rp, and atmospheric pressure Pa of the engine 12 are given, the corresponding temperature rise per unit scavenging ratio Tsp is derived from the map and set. The temperature rise per unit scavenging ratio Tsp is set to be higher as the engine speed Ne of the engine 12 is higher, higher as the port injection ratio Rp is higher, and higher as the atmospheric pressure Pa is lower. The reason for setting the temperature rise per unit scavenging ratio Tsp to be higher as the engine speed Ne of the engine 12 is higher is based on the fact that the scavenging amount per unit time increases as the engine speed Ne of the engine 12 is higher. The reason for setting the temperature rise per unit scavenging ratio Tsp to be higher as the port injection ratio Rp is higher is based on the fact that the amount of unburned fuel flowing into the purification device 37 per unit time due to scavenging increases as the port injection ratio Rp is higher. The reason for setting the temperature rise per unit scavenging ratio Tsp to be higher as the atmospheric pressure Pa is lower is based on the fact that the back pressure decreases and the scavenging amount increases as the atmospheric pressure Pa decreases.

[0032] When the temperature rise per unit scavenging ratio Tsp is set, the scavenging temperature correction ΔTs is set by multiplying the difference between the input scavenging ratio Sc and the steady-state scavenging ratio Sst by the temperature rise per unit scavenging ratio Tsp (step S130). The steady-state scavenging ratio Sst is the scavenging ratio when the engine speed Ne of the engine 12 (for example, 1500 rpm or 2000 rpm, etc.), the port injection ratio Rp (for example, Rp = 0.3 or 0.5, etc.), and the atmospheric pressure Pa (for example, Pa = 0.1 MPa, etc.) are predetermined.

[0033] When the scavenging temperature correction ΔTs is set in this way, other temperature corrections ΔT1, ΔT2…ΔTn other than the scavenging temperature correction ΔTs necessary for estimating the catalyst temperature Tc are input (step S140). Examples of other temperature corrections ΔT1, ΔT2…ΔTn include temperature correction for temperature drop due to vehicle speed V, temperature correction for temperature rise due to cylinder-by-cylinder injection vibration control, temperature correction for temperature rise due to ignition retard, and temperature correction for temperature drop due to fuel increment. The temperature correction for temperature drop due to vehicle speed V is a temperature correction in which the greater the vehicle speed V, the greater the temperature drop of the catalyst temperature Tc. The temperature correction for temperature rise due to cylinder-by-cylinder injection vibration control is a temperature correction by control that changes the air-fuel ratio for each cylinder to raise the catalyst temperature Tc. The temperature correction for temperature rise due to ignition retard is a temperature correction in which the greater the ignition retard angle from the basic ignition timing, the greater the temperature rise of the catalyst temperature Tc. The temperature correction for temperature drop due to fuel increment is a temperature correction in which the greater the fuel increment from the basic fuel injection amount, the greater the temperature drop of the catalyst temperature Tc. The setting methods for these other temperature corrections ΔT1, ΔT2…ΔTn are based on well-known methods and do not form the core of the present invention, so further detailed description is omitted.

[0034] Then, the scavenging temperature correction ΔTs and other temperature corrections ΔT1, ΔT2…ΔTn are added to and subtracted from the basic catalyst temperature Tcb to estimate the catalyst temperature Tc (step S150), and this process is terminated. As described above, the estimated catalyst temperature Tc is compared with a predetermined threshold value Tref assuming that a function degradation occurs, and when the catalyst temperature Tc is equal to or higher than the threshold value Tref, a fuel increment for increasing the fuel injection amount is performed and used to cool the catalyst bed.

[0035] In the engine device 10 described above, the temperature rise Tsp per unit scavenging ratio is set based on the engine speed Ne, the port injection ratio Rp, and the atmospheric pressure Pa of the engine 12, and the scavenging temperature correction ΔTs is set by multiplying the difference between the scavenging ratio Sc and the steady-state scavenging ratio Sst by the temperature rise Tsp per unit scavenging ratio. Then, the catalyst temperature Tc is estimated by adding or subtracting the scavenging temperature correction ΔTs and other temperature corrections ΔT1, ΔT2... ΔTn estimated based on the engine speed Ne and the load factor KL (engine load) of the engine 12. In this way, since the temperature rise Tsp per unit scavenging ratio is set based on the atmospheric pressure Pa to set the scavenging temperature correction ΔTs, the scavenging temperature correction ΔTs can be obtained more appropriately even in highlands with a low atmospheric pressure Pa, and the catalyst temperature Tc can be estimated more appropriately. Also, since the temperature rise Tsp per unit scavenging ratio is set based on the port injection ratio Rp to set the scavenging temperature correction ΔTs, the scavenging temperature correction ΔTs corresponding to the port injection ratio Rp can be obtained, and the catalyst temperature Tc can be estimated more appropriately. As a result, the catalyst temperature Tc can be estimated more appropriately.

[0036] In the engine device 10 of the embodiment, as temperature corrections used when estimating the catalyst temperature Tc, in addition to the scavenging temperature correction ΔTs, a temperature correction for temperature decrease due to the vehicle speed V, a temperature correction for temperature increase due to in-cylinder injection vibration control, a temperature correction for temperature increase due to ignition retard, and a temperature correction for temperature decrease due to fuel increment are used. However, some of these temperature corrections may be used, or different temperature corrections may be used in whole or in part together with these temperature corrections.

[0037] In the engine device 10 of the embodiment, as the engine 12, one in which the in-cylinder injection valve 29 is arranged substantially at the center of the top of the combustion chamber 31 is used, but an engine in which the in-cylinder injection valve 29 is arranged on the side wall of the combustion chamber 31 may be used.

[0038] In the engine device 10 of the embodiment, the supercharger 40 is configured as a turbocharger in which a compressor 41 disposed in the intake pipe 23 and a turbine 42 disposed in the exhaust pipe 35 are connected via a rotating shaft 43. However, instead of this, a supercharger driven by the engine 12 or a motor may be configured as a supercharger disposed in the intake pipe 23.

[0039] The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the supercharger 40 corresponds to the "supercharger", the port injection valve 28 corresponds to the "port injection valve", the in-cylinder injection valve 29 corresponds to the "in-cylinder injection valve", the engine 12 corresponds to the "engine", the purification device 37 corresponds to the "purification device", and the electronic control unit 70 corresponds to the "control device".

[0040] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems is an example for specifically explaining the form for implementing the invention described in the column of means for solving the problems in the embodiment, and thus does not limit the elements of the invention described in the column of means for solving the problems. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the column of means for solving the problems.

[0041] As described above, the embodiments have been used to explain the forms for implementing the present invention. However, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Industrial Applicability

[0042] The present invention can be used in the manufacturing industry of engine devices and the like.

Explanation of Reference Numerals

[0043] 10 Engine device, 11 Fuel tank, 11a Internal pressure sensor, 11p Feed pump, 12 Engine, 14 Crankshaft, 14a Crank position sensor, 16 Fuel supply device, 17 Low-pressure supply pipe, 18 High-pressure pump, 18a Electromagnetic valve, 18b Check valve, 18c Plunger, 19 High-pressure supply pipe, 22 Air cleaner, 23 Intake pipe, 23a Airflow 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, 28a Combustion pressure sensor, 29 Intake valve, 30 Combustion chamber, 31 Spark plug, 32 Piston, 34 Exhaust valve, 35 Exhaust pipe, 35a Front air-fuel ratio sensor, 35b Rear air-fuel ratio sensor, 36 Bypass pipe, 37 Purification device, 38 Engine cooling system, 38a Circulation flow path, 38b Radiator, 38c Fan, 38d Fan motor, 38e Water pump, 38f Temperature sensor, 40 Supercharger, 41 Compressor, 42 Turbine, 43 Rotating shaft, 44 Wastegate valve, 45 Blow-off valve, 70 Electronic control unit, 72 Atmospheric pressure sensor.

Claims

1. An engine device equipped with a supercharger and having a port injection valve and an in-cylinder injection valve, a purification device having a purification catalyst for purifying exhaust gas from the engine, a control device for estimating the temperature of the purification catalyst by adding a temperature correction term due to scavenging to a basic estimated temperature based on the engine speed and load of the engine, characterized in that: When the engine speed is high, the control device increases the ratio of the fuel injection amount from the port injection valve to the total fuel injection amount from the port injection valve and the in-cylinder injection valve compared to when the engine speed is low, increases the ratio of the scavenging amount to the air amount passing through the intake valve (scavenging ratio) compared to when the scavenging ratio is small, and increases the temperature rise per unit scavenging ratio using the scavenging ratio. The control device determines the temperature correction term due to scavenging by multiplying the difference between the current scavenging ratio and the steady-state scavenging ratio as the scavenging ratio at a predetermined engine speed, a predetermined port injection ratio, and a predetermined atmospheric pressure by the temperature rise per unit scavenging ratio. An engine device characterized by the above.

2. The engine device according to Claim 1, wherein the control device obtains the temperature rise per unit scavenging ratio using a four-dimensional map of the engine speed, the port injection ratio, the atmospheric pressure, and the temperature rise per unit scavenging ratio. An engine device.

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