Engine equipment

Abstract

To suppress disadvantages when removing deposit adhered and accumulated on a cylinder injection valve by increasing a fuel pressure to inject a fuel from the cylinder injection valve.SOLUTION: When executing deposition removal processing for removing thermo-setting deposit by injecting a fuel from a cylinder injection valve by using a fuel pressure of a high-pressure supply tube supplying the fuel into the cylinder injection valve as a predetermined pressure, ignition delay processing delaying ignition timing of an engine and auxiliary machine increase processing for increasing a load of an auxiliary machine are executed, and then purge restriction processing for restricting purging from an evaporated fuel processing device is executed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an engine device, and more particularly to an engine device including an engine having a port injection valve and a direct injection valve. [Background technology]

[0002] Conventionally, as an engine device of this type, one has been proposed in which an in-cylinder injection valve is provided near the intake valve near the top of the combustion chamber, and an ignition plug is provided near the in-cylinder injection valve (for example, see Patent Document 1). In this engine device, the airflow in the combustion chamber is strengthened by fuel injection from the in-cylinder injection valve, thereby suppressing variation between cylinders and promoting combustion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-030515 A Summary of the Invention [Problem to be solved by the invention]

[0004] Since the in-cylinder injection valve is disposed in the combustion chamber, its tip temperature is likely to become high. In particular, if an ignition plug is disposed near the in-cylinder injection valve, the ignition combustion occurs near the in-cylinder injection valve, so the tip temperature becomes high. When the tip temperature of the in-cylinder injection valve becomes high, the deposits that adhere and accumulate near the tip of the in-cylinder injection valve become thermosetting, and in order to remove them, it is necessary to inject the fuel from the in-cylinder injection valve by increasing the fuel pressure in the high-pressure supply pipe that supplies the fuel to the in-cylinder injection valve. Such a deposit removal process is performed when the vehicle is stopped and the engine is running at an idling speed. However, if the fuel pressure is increased and fuel is injected from the in-cylinder injection valve, even if the fuel injection amount from the in-cylinder injection valve is the minimum injection amount according to the fuel pressure, the fuel injection amount is more than the fuel required to operate the engine at the idling speed. If the intake air amount is maintained, the excess fuel is exhausted as unburned fuel, and if the intake air amount is controlled to be stoichiometric with respect to the fuel injection amount, problems such as the engine revving up or the engine idle speed increasing unnecessarily occur.

[0005] The main object of the engine apparatus of the present invention is to suppress problems that occur when deposits that adhere to and build up on a direct injection valve are removed by injecting fuel from the direct injection valve at high fuel pressure. [Means for solving the problem]

[0006] In order to achieve the above-mentioned main object, the engine device of the present invention employs the following means.

[0007] The engine device of the present invention comprises: an engine having a port injection valve and a direct injection valve; a fuel supply device including a low-pressure pump that pressure-feeds fuel from a fuel tank to a low-pressure supply pipe to which the port injection valve is connected, and a high-pressure pump that pressure-feeds fuel from the low-pressure supply pipe to a high-pressure supply pipe to which the in-cylinder injection valve is connected; a generator that generates electric power using power from the engine and supplies the generated electric power to an electric power line that supplies electric power to an auxiliary device; an evaporated fuel treatment device including a purge passage connected to a downstream side of the throttle valve of the intake pipe for evaporative fuel gas containing evaporated fuel generated in the fuel tank, and a purge control valve provided in the purge passage; a control device for controlling the engine, the fuel supply device, the generator, the auxiliary devices, and the evaporated fuel treatment device; An engine device comprising: When executing a deposit removal process for removing the thermosetting deposits by injecting fuel from the in-cylinder injection valve with the fuel pressure in the high-pressure supply pipe set to a predetermined pressure, the control device executes an ignition retard process for retarding an ignition timing of the engine and an accessory load increase process for increasing a load on the accessory, and then executes a purge limit process for limiting purging. It is characterized by:

[0008] In the engine device of the present invention, when performing a deposit removal process to remove thermosetting deposits by injecting fuel from the in-cylinder injection valve at a predetermined fuel pressure in the high-pressure supply pipe, the fuel pressure in the high-pressure supply pipe that supplies fuel to the in-cylinder injection valve is reduced, and an ignition retard process to retard the ignition timing of the engine and an accessory load increase process to increase the load of the accessory that receives power from a generator that generates electricity using the power from the engine are performed. The deposit removal process is performed when the vehicle is stopped and the engine is running at an idling speed, but if the fuel pressure in the high-pressure supply pipe is increased and fuel is injected from the in-cylinder injection valve, the amount of fuel injected may be greater than the amount required to operate the engine at an idling speed. In this case, if the intake air amount is maintained, the fuel injection amount will be excessive and unburned fuel will be exhausted, and if the intake air amount is controlled to be stoichiometric, the torque output from the engine will be excessive, causing the engine to rev up or the idling speed to increase unnecessarily. That is, if the intake air amount is controlled so that the fuel injection amount from the cylinder injection valve is the minimum injection amount according to the fuel pressure and is stoichiometric, the assumed torque assumed to be output from the engine at that time may be greater than the required torque required for the engine when it is operated at the idle speed. A part of the torque difference between the assumed torque and the required torque is eliminated by the ignition retardation process and the auxiliary load increase process. Then, after the ignition retardation process and the auxiliary load increase process, the purge from the evaporated fuel treatment device is limited. This makes it possible to limit the fuel supplied to the combustion chamber of the engine, and to further eliminate the torque difference between the assumed torque and the required torque. As a result, it is possible to suppress inconveniences such as exhausting unburned fuel when removing deposits attached and accumulated on the cylinder injection valve by increasing the fuel pressure and injecting fuel from the cylinder injection valve, or the engine revving up or the idle speed of the engine increasing unnecessarily.

[0009] In the engine device of the present invention, when executing the deposit removal process, the control device may execute the purge limitation process when the expected torque output from the engine when a minimum injection amount of fuel is injected from the direct injection valve is greater than the required torque required of the engine, even if the ignition retard process and the auxiliary load increase process are executed.

[0010] In the engine system of the present invention, the control device may, when executing the purge control process, impose a restriction based on the purge rate when purge concentration learning has been completed, and prioritize the purge concentration learning when the purge concentration learning has not been completed. In this way, the restriction based on the purge rate is suppressed using an inappropriate learned value due to the purge concentration learning not being completed, so that the purge restriction process can be performed more appropriately. In this case, the control device may prioritize the purge concentration learning when the assumed torque is greater than the required torque even if the purge rate is limited to a minimum value. [Brief description of the drawings]

[0011] [Figure 1] 1 is a configuration diagram showing an outline of the configuration of an engine device 10. FIG. [Diagram 2] 4 is an explanatory diagram showing an example of input / output signals of an electronic control unit 70. FIG. [Diagram 3] 13 is a flowchart showing an example of a deposit removal process executed by an electronic control unit 70. [Figure 4] FIG. 4 is an explanatory diagram illustrating an assumed torque Tas, a required torque Te*, and a differential torque ΔT. [Diagram 5] FIG. 4 is an explanatory diagram showing an example of the breakdown of fuel contained in the mixture when a purge restriction that reduces the purge rate is imposed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0013] Fig. 1 is a schematic diagram showing the configuration of an engine system 10 according to an embodiment of the present invention, and Fig. 2 is an explanatory diagram showing an example of input / output signals of an electronic control unit 70. The engine system 10 according to the embodiment is mounted on a general vehicle that runs using power from an engine 12, or on various hybrid vehicles that are equipped with a motor in addition to the engine 12, and includes the engine 12, a supercharger 40, a fuel supply device 16, an evaporated fuel processing device 50, and an electronic control unit 70, as shown in Figs. 1 and 2.

[0014] The engine 12 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel supplied from a fuel tank 11. The engine 12 has a port injection valve 28 that injects fuel into an intake port, an in-cylinder injection valve 29 that injects fuel into a combustion chamber 31, and an ignition plug 32. The in-cylinder injection valve 29 is disposed approximately at the center of the top of the combustion chamber 31 and injects fuel in a spray form. The ignition plug 32 is disposed near 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. The engine 12 has the port injection valve 28 and the in-cylinder injection valve 29, and is therefore capable of operating in any one of a port injection mode, an in-cylinder injection mode, and a common injection mode. In the port injection mode, air purified by the air cleaner 22 is drawn into the intake pipe 23 and passes through the intercooler 25, the throttle valve 26, and the surge tank 27 in that order, and fuel is injected from the port injection valve 28 downstream of the surge tank 27 of the intake pipe 23 to mix the air and fuel. This mixture is drawn into the combustion chamber 31 through the intake valve 30, and is explosively combusted by an electric spark from the spark plug 32. The reciprocating motion of the piston 33, which is pushed down by the energy of the explosive combustion, is converted into the rotational motion of the crankshaft 14. In the in-cylinder injection mode, air is drawn into the combustion chamber 31 in the same manner as in the port injection mode, and fuel is injected from the in-cylinder injection valve 29 once or in multiple times during the intake stroke, compression stroke, or expansion stroke, and is explosively combusted by an electric spark from the spark plug 32 to obtain the rotational motion of the crankshaft 14. In particular, when fuel is injected during the expansion stroke, fuel injection from the in-cylinder injection valve 29 during the expansion stroke is synchronized with ignition from the spark plug 32 so that the spray-like fuel injected from the in-cylinder injection valve 29 can be ignited. In the shared injection mode, fuel is injected from the port injection valve 28 when air is drawn into the combustion chamber 31, and fuel is injected from the in-cylinder injection valve 29 once or multiple times during the intake stroke, compression stroke, or expansion stroke, and is exploded and burned by an electric spark from the spark plug 32 to generate rotational motion for the crankshaft 14.Exhaust discharged from the combustion chamber 31 to the exhaust pipe 35 via the exhaust valve 34 is discharged into the outside air via purification devices 37, 38 having a catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). A starter (not shown) that cranks the engine 12 and an alternator 48 that generates electricity using the power of the engine 12 are attached to the crankshaft 14. The alternator 48 supplies the generated electricity to a power line that supplies electricity from a battery (not shown) to the fan motor 38d and water pump 38e of the engine cooling system 38, the fan motor 39d and circulation pump 39e of the intercooler cooling system 39, etc.

[0015] 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. 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, the low-pressure supply pipe 17 is also provided with a check valve that allows fuel to flow in the direction from the feed pump 11p side to the port injection valve 28 side and regulates fuel flow in the opposite direction. In addition, 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 driven by power from the engine 12 (in the embodiment, the rotation of the intake camshaft that opens and closes the intake valve 30). The high-pressure pump 18 has an electromagnetic valve 18a connected to its intake port which opens and closes when pressurizing the fuel, a check valve 18b connected to its discharge port which regulates the backflow of fuel and maintains the fuel pressure in the high-pressure supply pipe 19, and a plunger 18c which operates by the rotation (rotation of the intake camshaft) of the engine 12. When the electromagnetic valve 18a is opened while the engine 12 is running, the high-pressure pump 18 sucks in fuel from the low-pressure supply pipe 17, and when the electromagnetic valve 18a is closed, the fuel compressed by the plunger 18c is intermittently sent to the high-pressure supply pipe 19 via the check valve 18b, thereby pressurizing the fuel to be supplied to the high-pressure supply pipe 19. Note that when the high-pressure pump 18 is driven, the fuel pressure in the low-pressure supply pipe 17 and the fuel pressure (fuel pressure) in the high-pressure supply pipe 19 pulsate in response to the rotation of the engine 12 (rotation of the intake camshaft).

[0016] The engine 12 is provided with an engine cooling system 38 that cools the engine 12 with a heat exchange medium (cooling water, etc.). The engine cooling system 38 includes a circulation flow path 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 (water, etc.) is cooled by outside air. A water pump 38e that circulates the heat exchange medium is attached to the circulation flow path 38a.

[0017] 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 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 downstream side of the compressor 41 in the intake pipe 23, and is controlled by the electronic control unit 70.

[0018] In this turbocharger 40, the opening degree of the wastegate valve 44 is adjusted to adjust the distribution ratio between the amount of exhaust gas flowing through the bypass pipe 36 and the amount of exhaust gas flowing through the turbine 42, thereby adjusting the rotational driving force of the turbine 42, adjusting the amount of air compressed by the compressor 41, and adjusting the supercharging pressure (intake pressure) of the engine 12. In detail, the distribution ratio is adjusted so that the smaller the opening degree of the wastegate 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 42. When the wastegate valve 44 is fully open, the engine 12 can operate in the same manner as a naturally aspirated engine without the turbocharger 40.

[0019] In addition, in the turbocharger 40, when the pressure downstream of the compressor 41 in the intake pipe 23 is somewhat higher than the pressure upstream of the intake pipe 23, the blow-off valve 45 is opened to release the excess pressure downstream of the compressor 41. Note that, instead of a valve controlled by the electronic control unit 70, the blow-off valve 45 may be configured as a check valve that opens when the pressure downstream of the compressor 41 in the intake pipe 23 becomes somewhat higher than the pressure upstream of the intake pipe 23.

[0020] An intercooler cooling system 39 that cools the heat exchange medium (cooling water, etc.) of the intercooler 25 is attached to the intercooler 25. The intercooler cooling system 39 includes a circulation flow path 39a that circulates the heat exchange medium through a heat exchange medium flow path (not shown) formed in the intercooler 25 and a radiator 39b. A fan 39c driven by a fan motor 39d is attached to the radiator 39b, and the internal heat exchange medium (water, etc.) is cooled by outside air. A circulation pump 39e that circulates the heat exchange medium is attached to the circulation flow path 39a.

[0021] The evaporative fuel treatment device 50 is a device for purging the evaporative fuel gas (purged gas) generated in the fuel tank 11 by supplying it to the intake pipe 23 of the engine 12, and is equipped with an inlet passage 52, an opening / closing valve 53, a bypass passage 54, relief valves 55a, 55b, a canister 56, a purge passage 62, a buffer section 64, and a purge control valve 65.

[0022] The introduction passage 52 is connected to the fuel tank 11 and the canister 56. The opening and closing valve 53 is provided in the introduction passage 52 and is configured as a normally closed type electromagnetic valve. The opening and closing valve 53 is controlled by an electronic control unit 70.

[0023] The bypass passage 54 bypasses the fuel tank 11 side and the canister 56 side through the opening / closing valve 53 of the introduction passage 52, and has branching portions 54a and 54b where the two branches join together. The relief valve 55a is provided at the branching portion 54a and configured as a check valve, and opens when the pressure on the fuel tank 11 side becomes somewhat higher than the pressure on the canister 56 side. The relief valve 55b is provided at the branching portion 54b and configured as a check valve, and opens when the pressure on the canister 56 side becomes somewhat higher than the pressure on the fuel tank 11 side.

[0024] The canister 56 is connected to the introduction passage 52 and is open to the atmosphere via an atmosphere vent passage 57. The inside of the canister 56 is filled with an adsorbent, such as activated carbon, capable of adsorbing evaporated fuel from the fuel tank 11. An air filter 58 is provided in the atmosphere vent passage 57.

[0025] One end of the purge passage 62 is connected to the vicinity of the canister 56 of the introduction passage 52, and the other end is connected to a position between the throttle valve 26 and the surge tank 27 of the intake pipe 23. A buffer 64 and a purge control valve 65 are attached to the purge passage 62. The inside of the buffer portion 64 is filled with an adsorbent such as activated carbon capable of adsorbing evaporated fuel from the fuel tank 11 and the canister 56. The purge control valve 65 is configured as a normally closed type electromagnetic valve. This purge control valve 65 is controlled by an electronic control unit 70.

[0026] The evaporated fuel processing device 50 thus configured basically operates as follows: When the pressure downstream of the throttle valve 26 of the intake pipe 23 (surge pressure Ps, described later) is negative and the opening / closing valve 53 and the purge control valve 65 are open, evaporated fuel gas (purged gas) generated in the fuel tank 11 and evaporated fuel gas desorbed from the canister 56 are supplied to the intake pipe 23 downstream of the throttle valve 26 via the introduction passage 52 and the purge passage 62.

[0027] The electronic control unit 70 is configured as a microprocessor with a CPU at its core, and in addition to the CPU, is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, a non-volatile flash memory for storing and holding data, an input / output port, and a communication port. Signals from various sensors are input to the electronic control unit 70 via the input ports.

[0028] Examples of signals input to the electronic control unit 70 include a tank internal pressure Ptnk from an internal pressure sensor 11a that detects the pressure inside the fuel tank 11, a crank angle θcr from a crank position sensor 14a that detects the rotational position of the crankshaft 14 of the engine 12, a coolant temperature Tw from a water temperature sensor 38f that detects the temperature of the coolant for the engine 12, and a throttle opening TH from a throttle position sensor 26a that detects the opening of the throttle valve 26. Another example of signals input to the electronic control unit 70 is a cam position θca from a cam position sensor (not shown) that detects the rotational positions of an intake camshaft that opens and closes the intake valve 30 and an exhaust camshaft that opens and closes the exhaust valve 34. Other examples include the intake air amount Qa from the air flow meter 23a attached upstream of the compressor 41 of the intake pipe 23, the intake air temperature Tin from the intake air temperature sensor 23t attached upstream of the compressor 41 of the intake pipe 23, the intake pressure (pre-compressor pressure) Pin from the intake pressure sensor 23b attached upstream of the compressor 41 of the intake pipe 23, and the boost pressure Pc from the boost pressure sensor 23c attached between the compressor 41 of the intake pipe 23 and the intercooler 25. Other examples include the surge pressure (post-throttle 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. Other examples include the low-pressure fuel pressure Pfp from the fuel pressure sensor 28a that detects the pressure of the fuel supplied to the port injection valve 28, and the high-pressure fuel pressure Pfd from the fuel pressure sensor 29a that detects the pressure of the fuel supplied to the in-cylinder injection valve 29. Examples of the air-fuel ratio include a front air-fuel ratio AF1 from a front air-fuel ratio sensor 35a attached upstream of the purification device 37 of the exhaust pipe 35, and a rear air-fuel ratio AF2 from a rear air-fuel ratio sensor 35b attached downstream of the purification device 37 of the exhaust pipe 35. Examples of the air-fuel ratio include an intercooler medium temperature Tic from a temperature sensor 39f attached to a circulation flow path 39a of the intercooler cooling system 39, and an opening degree Opv of the purge control valve 65 from a purge control valve position sensor 65a.

[0029] Various control signals are output from the electronic control unit 70 via the output port. Examples of the signals output from the electronic control unit 70 include a control signal to the alternator 48, 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 spark plug 32. Examples of the signals output from the electronic control unit 70 include a drive signal to the fan motor 38d and the water pump 38e of the engine cooling device 38, and a drive signal to the fan motor 39d and the circulation pump 39e of the intercooler cooling device 39. Examples of the signals include a control signal to the wastegate valve 44, a control signal to the blow-off valve 45, a control signal to the opening / closing valve 53, and a control signal to the purge control valve 65.

[0030] The electronic control unit 70 calculates the rotation speed Ne and the load factor KL (the ratio of the volume of air actually taken in one cycle to the stroke volume per cycle of the engine 12) of the engine 12. The rotation 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 amount of intake air Qa from the air flow meter 23a and the rotation speed Ne.

[0031] In the engine system 10 of this embodiment configured as described above, the electronic control unit 70 performs intake air amount control that controls the opening of the throttle valve 26, fuel injection control that controls the amount of fuel injected from the in-cylinder injection valve 28, ignition control that controls the ignition timing of the spark plug 31, supercharging control that controls the opening of the wastegate valve 44, purge control that controls the opening of the purge control valve 65, and the like, based on the required load rate KL* of the engine 12.

[0032] Next, the operation of the engine device 10 of the embodiment, particularly the operation during removal of the thermosetting deposit adhering and accumulating near the tip of the in-cylinder injection valve 29 will be described. The amount of the thermosetting deposit adhering and accumulating near the tip of the in-cylinder injection valve 29 is estimated, for example, by using a counter that counts up every time fuel is injected when the tip temperature Test of the in-cylinder injection valve 29 is equal to or higher than a predetermined temperature (e.g., 150°C). Then, when the counter reaches a predetermined value or more, a deposit removal process for removing the thermosetting deposit is executed. The deposit removal process is performed by injecting fuel from the in-cylinder injection valve 29 with the fuel pressure Pfd of the high-pressure supply pipe 19 that supplies fuel to the in-cylinder injection valve 29 set to a predetermined pressure (e.g., 20 MPa) while the vehicle is stopped and the engine 12 is operating at an idle speed Nidl. During such a deposit removal process, the fuel pressure Pfd in the high pressure supply pipe 19 is set to a predetermined pressure (e.g., 20 MPa), so that even if the fuel injection amount from the in-cylinder injection valve 29 is set to the minimum injection amount, the torque output from the engine 12 (assumed torque Tas) may be greater than the required torque Te* required for the engine 12 operating at the idle speed Nidl. In this case, problems may occur, such as unburned fuel being exhausted, the engine revving up, or the idle speed of the engine increasing unnecessarily. In the embodiment, in order to suppress such problems, the electronic control unit 70 executes a deposit removal process exemplified in FIG. 3.

[0033] When the deposit removal process is executed, the electronic control unit 70 first increases the load of low NV auxiliary equipment that generates relatively little noise and vibration (step S100). Examples of the auxiliary equipment include the feed pump 11p, the water pump 38e and the fan motor 38d of the engine cooling system 38, and the circulation pump 38e and the fan motor 39d of the intercooler cooling system 39. Among these, the low NV auxiliary equipment includes the feed pump 11p, the water pump 38e of the engine cooling system 38, and the circulation pump 38 of the intercooler cooling system 39. The load increase of the low NV auxiliary equipment is performed by increasing the discharge pressure of the feed pump 11p to about the opening pressure (for example, 550 kPa or 600 kPa) of a relief valve (not shown) to prevent the fuel pressure Pfp of the low pressure supply pipe 17 from becoming too high, and by operating the water pump 38e of the engine cooling system 38 and the circulation pump 38 of the intercooler cooling system 39 at maximum drive. Increasing the load on the low NV accessories in this way reduces the voltage of the power line that supplies power to the accessories, which increases the load torque of the alternator 48, thereby making it possible to increase the required torque Te* required to operate the engine 12 at the idle speed Nidl. This makes it possible to reduce the differential torque ΔT, which is the difference between the assumed torque Tas and the required torque Te*, and to suppress the above-mentioned problems.

[0034] Next, the torque (assumed torque Tas) output from the engine 12 when the minimum injection amount of fuel is injected from the direct injection valve 29 is calculated (step S110). The assumed torque Tas can be calculated by converting the minimum injection amount of the direct injection valve 29 plus the amount of fuel supplied by purging into an energy amount, and dividing this by the idle speed of the engine 12.

[0035] After the estimated torque Tas is calculated, the torque requirement Te* required for the engine 12 operating at the idle speed Nild is subtracted from the estimated torque Tas to calculate the torque difference ΔT (step S120). FIG. 4 shows the estimated torque Tas, the torque requirement Te*, and the torque difference ΔT. Next, within the range of the ignition retard limit θlim, the ignition timing θs is set which is retarded from the normal ignition timing θ when the engine 12 operates at the idle speed according to the torque difference ΔT (step S130). The ignition retard limit θlim is the ignition timing at the combustion limit where no misfire occurs. In the embodiment, the retard amount of the ignition timing θ is obtained by determining the relationship between the torque difference ΔT and the retard amount in advance by experiments or the like and storing it as a retard amount setting map, and deriving the corresponding retard amount from the map when the torque difference ΔT is given. The retarded ignition timing θ can be obtained by adding the determined retard amount to the normal ignition timing θ when the engine 12 operates at the idle speed. The relationship between the differential torque ΔT and the retarded ignition timing θ may be determined in advance by experiments or the like and stored as a map for setting the retarded ignition timing, and when the differential torque ΔT is given, the corresponding retarded ignition timing θ may be derived from the map. The retard amount and the retarded ignition timing θ in such a map are upper-limit guarded by the ignition retard limit θlim. Therefore, when the differential torque ΔT is large, the retarded ignition timing θ is set to the ignition retard limit θlim. When the retarded ignition timing θ is set, ignition is performed at the retarded ignition timing θ, so that combustion becomes slow and the amount of air and fuel required to output the required torque Te* from the engine 12 increases. This makes it possible to reduce the expected torque Tas and the differential torque ΔT, which is the difference between the expected torque Tas and the required torque Te*, and thus to suppress the above-mentioned inconvenience.

[0036] Next, it is determined whether the retarded ignition timing θ coincides with the ignition retard limit θlim (step S140). If it is determined that the ignition timing θ does not coincide with the ignition retard limit θlim, it is determined that the torque difference ΔT has been eliminated due to the load increase of the low NV auxiliary and the ignition retard, and this process is terminated.

[0037] When it is determined in step S140 that the ignition timing θ coincides with the ignition retard limit θlim, the load of the high NV auxiliary that generates relatively large noise and vibration is increased (step S150), and a predetermined time is awaited (step S160). An example of the high NV auxiliary is the fan motor 38d of the engine cooling system 38. The load of the fan motor 38d of the engine cooling system 38 is preferably increased gradually until the differential torque ΔT is eliminated. The predetermined time can be the time required to increase the load W of the high NV auxiliary or a time slightly longer than that time.

[0038] Next, the assumed torque Tas is calculated (step S180), and it is determined whether the assumed torque Tas is greater than the required torque Te* (step S190). The assumed torque Tas in this case is the torque output from the engine 12 when the engine 12 is operated at the idle speed Nidl while the minimum injection amount is injected from the direct injection valve 29 and the intake air amount is controlled to be stoichiometric with the ignition retard processing and the auxiliary load increase processing being performed, and can be calculated by subtracting the amount of energy subtracted due to the ignition retard from the amount of energy converted from the minimum injection amount of the direct injection valve 29 plus the amount of fuel supplied by purging, and dividing the result by the idle speed of the engine 12. If it is determined that the assumed torque Tas is equal to or less than the required torque Te*, it is determined that the differential torque ΔT is eliminated due to the load increase of the high NV auxiliary, and this processing is terminated.

[0039] When it is determined in step S180 that the assumed torque Tas is greater than the required torque Te*, it is determined whether or not purge concentration learning has been completed (step S190). The purge concentration learning can be performed by learning the air-fuel ratio through air-fuel ratio feedback control with the purge control valve 65 closed, and then maintaining this state and opening the purge control valve 65 by a predetermined degree, based on the correction amount through the air-fuel ratio feedback control. In this embodiment, a specific learning item is a concentration learning value fgpg (% / %) as a fuel correction ratio for a unit purge rate to achieve stoichiometric (theoretical air-fuel ratio).

[0040] When it is determined in step S190 that the purge concentration learning is completed, a purge restriction that reduces the purge rate is imposed (step S200), and the process is terminated. When it is determined that the purge concentration learning is not completed, a purge restriction that closes the purge control valve 65 to cut the purge is imposed (step S210), and the process is terminated. FIG. 5 shows an example of the breakdown of fuel contained in the mixture when a purge restriction that reduces the purge rate is imposed. The leftmost is the minimum injection amount to be injected from the in-cylinder injection valve 29 during the deposit removal process, the second from the left is the breakdown of fuel when the engine 12 is operated at the idle speed Nidl before the deposit removal process is performed, the third from the left is the breakdown of fuel when the load rate KL of the engine 12 is increased by performing the ignition retard process and the auxiliary load increase process during the deposit removal process, and the rightmost is the breakdown of fuel when a purge restriction is imposed so that the fuel injection amount from the in-cylinder injection valve 29 is the minimum injection amount for the third from the left. The breakdown of the fuel is, from the bottom up, an injection amount as the fuel injection amount from the in-cylinder injection valve 29, a purged amount as the fuel amount supplied by purging, and a dilution amount as the fuel amount due to vaporization of fuel adhering to the cylinder, etc. That is, in the purge restriction, the purge amount can be calculated by subtracting the injection amount and the dilution amount from the total fuel amount when the load rate KL of the engine 12 is increased by executing the ignition retardation processing and the auxiliary load increase processing, using the concentration learning value fgpg. Note that even if the purge rate is set to the minimum value, restriction by purge cut (closing of the purge control valve 65) may be performed when the assumed torque Tas becomes larger than the required torque Te*.

[0041] In the engine device 10 of the embodiment described above, during the deposit removal process in which fuel is injected from the in-cylinder injection valve 29 with the fuel pressure Pfd of the high-pressure supply pipe 19 set to a predetermined pressure (e.g., 20 MPa) while the vehicle is stopped and the engine 12 is operating at the idle speed Nidl, a low NV auxiliary load increase process that increases the load of the low NV auxiliary is performed, and an ignition retard process that retards the ignition timing θ of the engine 12 is performed, and a high NV auxiliary load increase process that increases the load of the high NV auxiliary is also performed. Then, a purge restriction is imposed thereafter. This makes it possible to suppress inconveniences such as exhausting unburned fuel during the deposit removal process, engine revving, and unnecessary increase in the idle speed of the engine. Moreover, even if the low NV auxiliary load increase process and the ignition retard process are performed and the high NV auxiliary load increase process is performed, the purge restriction is imposed when the expected torque Tas is greater than the required torque Te*, so that unnecessary purge restriction can be suppressed.

[0042] In the engine system 10 of the embodiment, when a purge restriction is imposed during the deposit removal process, if the purge concentration learning is completed, the purge restriction is set to a smaller purge rate, and if the purge concentration learning is not completed, the purge restriction is set to cut the purge. This makes it possible to prevent the purge restriction using an inappropriate purge rate due to the incomplete purge concentration learning.

[0043] In the engine system 10 of the embodiment, the load of the low NV auxiliary devices is increased and the ignition timing θ of the engine 12 is retarded during the deposit removal process, and then the load of the high NV auxiliary devices is increased. However, the load of the low NV auxiliary devices may be increased and the load of the high NV auxiliary devices may be increased at the same time during the deposit removal process.

[0044] In the engine system 10 of the embodiment, the process of increasing the load on the auxiliary devices and the process of retarding the ignition timing are performed during the deposit removal process, but the process of increasing the idle speed Nidl of the engine 12 may be performed instead. In this case, all of the processes of increasing the load on the auxiliary devices, the process of retarding the ignition timing, and the process of increasing the idle speed Nidl of the engine 12 may be performed, or any two of them, or only one of them may be performed.

[0045] In the engine system 10 of the embodiment, the auxiliary machines include the feed pump 11p, the water pump 38e and the fan motor 38d of the engine cooling system 38, and the circulation pump 38e and the fan motor 39d of the intercooler cooling system 39, but the auxiliary machines may be part of these or may be auxiliary machines that can increase other electrical loads.

[0046] In the engine device 10 of the embodiment, the engine 12 used has an in-cylinder injection valve 29 arranged approximately in the center of the top of the combustion chamber 31, but it is also possible to use an engine in which the in-cylinder injection valve 29 is arranged on the side wall (side) of the combustion chamber 31.

[0047] In the engine system 10 of the embodiment, the supercharger 40 is configured as a turbocharger in which a compressor 41 arranged in the intake pipe 23 and a turbine 42 arranged in the exhaust pipe 35 are connected via a rotating shaft 43. However, instead of this, the supercharger may be configured as a compressor driven by the engine 12 or a motor and arranged in the intake pipe 23. Also, the supercharger 40 may not be provided.

[0048] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be described below. In the embodiment, 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 fuel tank 11 corresponds to the "fuel tank", the feed pump 11p corresponds to the "low pressure pump", the high pressure pump 18 corresponds to the "high pressure pump", the fuel supply device 16 corresponds to the "fuel supply device", the fuel tank 11 corresponds to the "fuel tank", the purge passage 62 corresponds to the "purge passage", the purge control valve 65 corresponds to the "purge control valve", the evaporated fuel processing device 50 corresponds to the "evaporated fuel processing device", and the electronic control unit 70 corresponds to the "control device".

[0049] The correspondence between the main elements of the Examples and the main elements of the invention described in the Summary of the Problem column does not limit the elements of the invention described in the Summary of the Problem column, since the Examples are examples for specifically explaining the mode for implementing the invention described in the Summary of the Problem column. In other words, the interpretation of the invention described in the Summary of the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Summary of the Problem column.

[0050] Although the form for carrying out the present invention has been described above using examples, the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the gist of the present invention. [Industrial Applicability]

[0051] The present invention can be used in the engine device manufacturing industry and the like. [Explanation of symbols]

[0052] 10 engine device, 11 fuel tank, 11a internal pressure sensor, 12 engine, 14 crankshaft, 14a crank position sensor, 16 fuel supply device, 17 low pressure supply pipe, 18 high pressure pump, 18a solenoid valve, 18b check valve, 18c plunger, 19 high pressure supply pipe, 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, 28a fuel 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, 39 intercooler cooling system, 39a circulation flow path, 39b radiator, 39c fan, 39d fan motor, 39e circulation pump, 39f temperature sensor, 40 turbocharger, 41 compressor, 42 turbine, 43 rotating shaft, 44 wastegate valve, 45 blow-off valve, 48 alternator, 50 evaporated fuel treatment device, 52 introduction passage, 53 opening / closing valve, 54 bypass passage, 54a, 54b branching portion, 55a, 55b relief valve, 55b relief valve, 56 canister, 57 atmospheric release passage, 58 Air filter, 62 purge passage, 64 buffer section, 65 purge control valve, 65a purge control valve position sensor, 70 electronic control unit.

Claims

1. an engine having a port injection valve and a direct injection valve; a fuel supply device including a low-pressure pump that pressure-feeds fuel from a fuel tank to a low-pressure supply pipe to which the port injection valve is connected, and a high-pressure pump that pressure-feeds fuel from the low-pressure supply pipe to a high-pressure supply pipe to which the in-cylinder injection valve is connected; a generator that generates electric power using power from the engine and supplies the generated electric power to an electric power line that supplies electric power to an auxiliary device; an evaporated fuel treatment device including a purge passage connected to an intake pipe downstream of a throttle valve for receiving evaporated fuel gas including evaporated fuel generated in the fuel tank, and a purge control valve provided in the purge passage; a control device for controlling the engine, the fuel supply device, the generator, the auxiliary devices, and the evaporated fuel treatment device; An engine device comprising: When executing a deposit removal process for removing thermosetting deposits by injecting fuel from the in-cylinder injection valve with the fuel pressure in the high-pressure supply pipe set to a predetermined pressure, the control device executes an ignition retard process for retarding an ignition timing of the engine and an accessory load increase process for increasing a load on the accessory, and then executes a purge limit process for limiting purging. An engine device characterized by:

2. 2. The engine device according to claim 1, When the control device executes the purge limiting process, the control device performs a limiting process based on a purge rate when purge concentration learning has been completed, and performs a purge cut when the purge concentration learning has not been completed. Engine equipment.

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