JP7658239B2 - Engine equipment - Google Patents

Description

The present invention relates to an engine device, and more specifically, to an engine device equipped with an engine having a port injection valve and an in-cylinder injection valve.

Conventionally, engine devices of this type have been proposed that have an in-cylinder injection valve near the intake valve near the top of the combustion chamber, and an ignition plug near the in-cylinder injection valve (see, for example, Patent Document 1). In this engine device, fuel is injected from the in-cylinder injection valve to strengthen the airflow in the combustion chamber, thereby suppressing variation between cylinders and promoting combustion.

JP 2009-030515 A

Since the in-cylinder injection valve is placed inside the combustion chamber, its tip temperature tends to become high. In particular, if an ignition plug is placed 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 their properties are different from those of the conventional thermoplastic deposits that adhere and accumulate at relatively low temperatures. For this reason, the challenge is to effectively remove both the thermoplastic deposits that adhere and accumulate at relatively low temperatures and the thermosetting deposits that adhere and accumulate at relatively high temperatures.

The main purpose of the engine device of the present invention is to more appropriately remove deposits that build up on the in-cylinder injection valve.

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

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 control device for controlling the engine and the fuel supply device;
An engine device comprising:
The control device includes:
when it is estimated that a thermoplastic deposit has accumulated in the cylinder injection valve, a first removal process is performed in which the fuel pressure in the high-pressure supply pipe is increased to a first predetermined pressure or higher to inject fuel from the cylinder injection valve, thereby removing the thermoplastic deposit;
when it is estimated that a thermosetting deposit has accumulated in the cylinder injection valve, a second removal process is performed in which the fuel pressure in the high-pressure supply pipe is increased to a second predetermined pressure or higher, which is higher than the first predetermined pressure, and fuel is injected from the cylinder injection valve to remove the thermosetting deposit.
It is characterized by:

In the engine device of the present invention, when it is estimated that thermoplastic deposits have accumulated on the in-cylinder injection valve, a first removal process is performed in which the fuel pressure in the high-pressure supply pipe that supplies fuel to the in-cylinder injection valve is set to a first predetermined pressure or higher and fuel is injected from the in-cylinder injection valve to remove the thermoplastic deposits. This makes it possible to remove thermoplastic deposits that have adhered and accumulated near the tip of the in-cylinder injection valve. Also, when it is estimated that thermosetting deposits have accumulated on the in-cylinder injection valve, a second removal process is performed in which the fuel pressure in the high-pressure supply pipe is set to a second predetermined pressure or higher, which is higher than the first predetermined pressure, and fuel is injected from the in-cylinder injection valve to remove the thermosetting deposits. This makes it possible to remove thermosetting deposits that have adhered and accumulated near the tip of the in-cylinder injection valve. As a result, deposits that have accumulated on the in-cylinder injection valve can be more appropriately removed.

In the engine device of the present invention, the control device may perform the first removal process when a first counter reflecting the degree of accumulation of the thermoplastic deposit reaches a first predetermined value or more, and perform the second removal process when a second counter reflecting the degree of accumulation of the thermosetting deposit reaches a second predetermined value or more. By using the first and second counters, the amount of adhesion and accumulation of the thermoplastic deposit and the thermosetting deposit can be properly estimated, and the first removal process and the second removal process can be performed at a more appropriate time. In addition, the first counter may be increased by a first up amount when the fuel pressure in the high-pressure supply pipe is less than the first predetermined pressure and fuel injection is performed from the port injection valve when the cooling water temperature of the engine is above a predetermined water temperature, and decreased by a first down amount when the fuel pressure in the high-pressure supply pipe is above the first predetermined pressure and fuel injection is performed from the in-cylinder injection valve; and the second counter may be increased by a second up amount when the fuel pressure in the high-pressure supply pipe is less than the second predetermined pressure and the tip temperature of the in-cylinder injection valve is above the predetermined temperature and fuel injection is performed from the port injection valve or the in-cylinder injection valve when the cooling water temperature of the engine is above the predetermined water temperature, and decreased by a second down amount when the fuel pressure in the high-pressure supply pipe is above the second predetermined pressure and fuel injection is performed from the in-cylinder injection valve. Thermoplastic deposits, the accumulation of which is counted by the first counter, are gradually removed by fuel injection from the in-cylinder injection valve when the fuel pressure in the high-pressure supply pipe is equal to or higher than a first predetermined pressure. Therefore, by taking into account the counting down of the first counter, the first counter can more accurately indicate the accumulation amount of thermoplastic deposits. Also, thermosetting deposits, the accumulation of which is counted by the second counter, are gradually removed by fuel injection from the in-cylinder injection valve when the fuel pressure in the high-pressure supply pipe is equal to or higher than a second predetermined pressure. Therefore, by taking into account the counting down of the second counter, the second counter can more accurately indicate the accumulation amount of thermosetting deposits. As a result, deposits that accumulate on the in-cylinder injection valve can be more accurately removed.

1 is a diagram showing an outline of the configuration of an engine device 10. FIG. 3 is an explanatory diagram showing an example of input/output signals of an electronic control unit 70. FIG. 4 is a flowchart showing an example of a deposit removal process executed by an electronic control unit 70. 11 is a table showing a list of count processing conditions of a first counter Cs. FIG. 4 is an explanatory diagram showing an example of a first down amount setting map; 11 is a table showing a list of count processing conditions of a second counter Ch . FIG. 11 is an explanatory diagram showing an example of a second down amount setting map;

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram showing the configuration of an engine device 10 according to one embodiment of the present invention, and Figure 2 is an explanatory diagram showing an example of input/output signals of an electronic control unit 70. The engine device 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 have a motor in addition to the engine 12, and includes an engine 12, a supercharger 40, a fuel supply device 16, and an electronic control unit 70, as shown in Figures 1 and 2.

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 that it can 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 can be operated in any one of a port injection mode, an in-cylinder injection mode, and a shared 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, the fuel injection from the in-cylinder injection valve 29 and the ignition from the spark plug 32 during the expansion stroke are synchronized 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 sucked 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 explosively burned by an electric spark from the spark plug 32 to obtain the rotational motion of the crankshaft 14. 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 purification devices 37, 38 having catalysts (three-way catalysts) that purify 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 power to the fan motor 38d, water pump 38e, etc. of the engine cooling system 38 from a battery (not shown).

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 through 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 arranged in the fuel tank 11. Although not shown, the low-pressure supply pipe 17 is also equipped with a check valve that allows fuel to flow from the feed pump 11p side to the port injection valve 28 side and regulates fuel flow in the opposite direction. In addition, 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 through 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 that opens and closes when pressurizing the fuel, a check valve 18b connected to its discharge port that regulates the backflow of fuel and maintains the fuel pressure in the high-pressure supply pipe 19, and a plunger 18c that operates with the rotation of the engine 12 (rotation of the intake camshaft). When the electromagnetic valve 18a is open while the engine 12 is running, the pump sucks in fuel from the low-pressure supply pipe 17, and when the electromagnetic valve 18a is closed, the pump compresses the fuel by the plunger 18c and intermittently sends the compressed fuel to the high-pressure supply pipe 19 through the check valve 18b, thereby pressurizing the fuel to be 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 (fuel pressure) in the high-pressure supply pipe 19 pulsates according to the rotation of the engine 12 (rotation of the intake camshaft).

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 has 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 (such as water) is cooled by outside air. A water pump 38e for circulating the heat exchange medium is attached to the circulation flow path 38a.

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 the bypass pipe 36 that connects the upstream side and downstream side of the turbine 42 in the exhaust pipe 35, and is controlled by the electronic control unit 70. The blow-off valve 45 is provided in the bypass pipe 24 that 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.

In this turbocharger 40, the opening 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 compressed air 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 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 way as a naturally aspirated engine without a turbocharger 40.

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, the blow-off valve 45 is opened to release 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.

The electronic control unit 70 is configured as a microprocessor with a CPU at its core, and in addition to the CPU, it 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.

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 cooling water temperature Tw from the water temperature sensor 38f that detects the temperature of the cooling water of the engine 12, and the throttle opening TH from the throttle position sensor 26a that detects the opening of the throttle valve 26. Also included are 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. 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 include a front air-fuel ratio AF1 from a front air-fuel ratio sensor 35a attached upstream of the purification device 37 in 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 in the exhaust pipe 35.

Various control signals are output from the electronic control unit 70 via the output port. 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 spark plug 32. Examples of signals 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 signals include a control signal to the wastegate valve 44, a control signal to the blow-off valve 45, and a control signal to the solenoid valve 18a.

The electronic control unit 70 calculates the engine 12 rotation speed Ne and 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). 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 intake air volume Qa from the air flow meter 23a and the rotation speed Ne.

In the engine device 10 of the embodiment thus configured, the electronic control unit 70 performs intake air volume control to control the opening of the throttle valve 26, fuel injection control to control the amount of fuel injected from the in-cylinder injection valve 28, ignition control to control the ignition timing of the spark plug 31, supercharging control to control the opening of the wastegate valve 44, and fuel pressure control in the high-pressure supply pipe 19 by opening and closing the solenoid valve 18a, based on the required load rate KL* of the engine 12.

Next, the operation of the engine device 10 of the embodiment, particularly the operation when removing deposits that have adhered and accumulated near the tip of the in-cylinder injection valve 29, will be described. FIG. 3 is a flow chart showing an example of a deposit removal process executed by the electronic control unit 70. This process is repeatedly executed every cycle (720 crank angles).

When the deposit removal process is executed, the electronic control unit 70 first executes a first counter process to count up or down a first counter Cs that reflects the amount of thermoplastic deposits that have adhered and accumulated near the tip of the in-cylinder injection valve 29 (step S100). Figure 4 shows a list of the count process conditions for the first counter Cs.

The first counter Cs counts up by a value of 1 when the following conditions are met: the high-pressure fuel pressure Pfd is less than the threshold Pref1, and the fuel injection from the port injection valve 28 is 100%, with the cooling water temperature Tw being equal to or higher than the threshold Tref. The threshold Tref1 is a threshold for determining whether the engine 12 is in a state where it has been warmed up to a certain extent, and for example, 50°C, 60°C, or 70°C can be used. The threshold Pref1 can be a lower limit fuel pressure that can remove thermoplastic deposits that have adhered and accumulated near the tip of the in-cylinder injection valve 29, and for example, 11 MPa, 12 MPa, 13 MPa, etc. can be used. In other words, when the high-pressure fuel pressure Pfd is equal to or higher than the threshold Pref1, it is considered that thermoplastic deposits will not adhere and accumulate near the tip of the in-cylinder injection valve 29.

The first counter Cs counts down by the first down amount ΔCs when both the condition that the high-pressure side fuel pressure Pfd is equal to or greater than the threshold Pref1 and the condition that the fuel injection from the port injection valve 28 is not 100% (the condition that the fuel is injected from the in-cylinder injection valve 29) are satisfied. In the embodiment, the first down amount ΔCs is determined in advance and stored as a first down amount setting map, and when the high-pressure side fuel pressure Pfd is given, the corresponding first down amount ΔCs is derived from the map. FIG. 5 shows an example of the first down amount setting map. As shown in the figure, the first down amount ΔCs is set to a value of 2 when the high-pressure side fuel pressure Pfd is equal to the threshold Pref1, and is set to increase as the high-pressure side fuel pressure Pfd increases in the range of the threshold Pref1 or greater. The first down amount setting map is stepped in order to make the first down amount ΔCs an integer. In this embodiment, the first counter Cs is set to a lower limit of 0.

After the first counter process is performed in this manner, it is determined whether the first counter Cs is equal to or greater than the threshold value Cref1 (step S110). The threshold value Cref1 is a threshold value for determining whether or not it is necessary to remove the thermoplastic deposit that has adhered and accumulated near the tip of the in-cylinder injection valve 29, and can be determined by experiment or the like depending on the characteristics of the engine 12. When it is determined that the first counter Cs is equal to or greater than the threshold value Cref1, the first removal flag Fcs is set to a value of 1 (step S120). The first removal flag Fcs is initially set to a value of 0, and is set to a value of 1 when a request is made to remove the thermoplastic deposit that has adhered and accumulated near the tip of the in-cylinder injection valve 29, and is set to a value of 0 when the removal of the deposit is completed.

When it is determined in step S110 that the first counter Cs is less than the threshold value Cref1, it is determined whether the first counter Cs has a value of 0 (step S130). When it is determined that the first counter Cs has a value of 0, the first removal flag Fcs is set to a value of 0 (step S140). When the first counter Cs is less than the threshold value Cref1 but is not a value of 0, the first counter Cs is neither counted up nor counted down.

Next, a second counter process is executed to count up or down the second counter Ch, which reflects the amount of thermosetting deposits that have accumulated near the tip of the in-cylinder injection valve 29 (step S150). Figure 6 shows a list of the count process conditions for the second counter Ch.

The second counter Ch is incremented by 1 when the condition that the tip temperature of the in-cylinder injection valve 29 is equal to or higher than the threshold Tref2 and the condition that the high-pressure side fuel pressure Pfd is less than the threshold Pref2 are both satisfied, with the cooling water temperature Tw being equal to or higher than the threshold Tref. The tip temperature Test of the in-cylinder injection valve 29 is estimated to be higher as the intake air amount Qa is larger and the cooling water temperature Tw is higher. In the embodiment, the relationship between the intake air amount Qa, the cooling water temperature Tw, and the tip temperature Test is obtained in advance and stored as a tip temperature setting map, and when the intake air amount Qa and the cooling water temperature Tw are given, the corresponding tip temperature Test is derived from the map to estimate it. The threshold Tref2 is determined as the lower limit temperature or a temperature in the vicinity of the temperature range at which thermosetting deposits are likely to adhere and accumulate near the tip of the in-cylinder injection valve 29, and can be, for example, 140°C, 150°C, or 160°C. The threshold value Pref2 can be the lower limit fuel pressure at which thermosetting deposits that have accumulated near the tip of the in-cylinder injection valve 29 can be removed, and can be, for example, 18 MPa, 20 MPa, or 22 MPa. Therefore, when it is determined that the high-pressure fuel pressure Pfd is equal to or greater than the threshold value Pref2, it is considered that thermosetting deposits will not accumulate near the tip of the in-cylinder injection valve 29.

The second counter Ch counts down by the second down amount ΔCh when all of the following conditions are met: the high-pressure fuel pressure Pfd is equal to or greater than the threshold Pref2, and the fuel injection from the port injection valve 28 is not 100% (the fuel is injected from the in-cylinder injection valve 29). In the embodiment, the relationship between the high-pressure fuel pressure Pfd and the second down amount ΔCh is predefined and stored as a second down amount setting map, and when the high-pressure fuel pressure Pfd is given, the corresponding second down amount ΔCh is derived from the map. FIG. 7 shows an example of the second down amount setting map. As shown in the figure, the second down amount ΔCh is set to a value of 6 when the high-pressure fuel pressure Pfd is equal to the threshold Pref2, and is set to increase as the high-pressure fuel pressure Pfd increases in the range of the threshold Pref2 or greater. The reason why the second down amount setting map is stepped is to make the second down amount ΔCh an integer. In this embodiment, the second counter Ch is set to a lower limit of 0.

When the second counter process is performed in this manner, it is determined whether the second counter Ch is equal to or greater than the threshold value Cref2 (step S160). The threshold value Cref2 is a threshold value for determining whether it is necessary to remove the thermosetting deposits that have adhered and accumulated near the tip of the in-cylinder injection valve 29, and can be determined by experiment or the like depending on the characteristics of the engine 12. When it is determined that the second counter Ch is equal to or greater than the threshold value Cref2, the second removal flag Fch is set to a value of 1 (step S170). The second removal flag Fch is initially set to a value of 0, and is set to a value of 1 when a request is made to remove the thermosetting deposits that have adhered and accumulated near the tip of the in-cylinder injection valve 29, and is set to a value of 0 when the removal of the deposits is completed.

When it is determined in step S160 that the second counter Ch is less than the threshold value Cref2, it is determined whether the second counter Ch has a value of 0 (step S180). When it is determined that the second counter Ch has a value of 0, the second removal flag Fch is set to a value of 0 (step S190). When the second counter Ch is less than the threshold value Cref2 but is not a value of 0, the second counter Ch is neither counted up nor counted down.

Next, it is determined whether the first removal flag Fcs is equal to 1 and the second removal flag Fch is equal to 0 (step S200). The first removal flag Fcs is equal to 1 when it is necessary to remove thermoplastic deposits, and the second removal flag Fch is equal to 1 when it is necessary to remove thermosetting deposits. Therefore, the determination in step S200 is whether it is necessary to remove thermoplastic deposits, but not yet necessary to remove thermosetting deposits.

When it is determined in step S200 that the first removal flag Fcs is equal to 1 and the second removal flag Fch is equal to 0, it is determined whether or not the conditions for performing the deposit removal process are met (step S210). Such conditions may include the vehicle being stopped, the engine 12 being warmed up, etc.

When it is determined in step S210 that the conditions for deposit removal processing are met, the high-pressure pump 18 is driven so that the high-pressure fuel pressure Pfd becomes the threshold value Pref1, and fuel is injected from the in-cylinder injection valve 29 at 100% (step S220). By injecting fuel from the in-cylinder injection valve 29 with the high-pressure fuel pressure Pfd set to the threshold value Pref1, the thermoplastic deposits that have adhered and accumulated near the tip of the in-cylinder injection valve 29 are removed. Note that this removal processing (first removal processing) in step S220 continues until the first counter Cs becomes 0 and the first removal flag Fcs is set to 0. Note that if the driver depresses the accelerator pedal during the first removal processing, for example, and the conditions for deposit removal processing are no longer met, the first removal processing is interrupted, but is resumed when the conditions for deposit removal processing are subsequently met.

Next, it is determined whether the second removal flag Fch is equal to the value 1 (step S230). When it is determined that the second removal flag Fch is equal to the value 1, it is determined whether the conditions for performing the deposit removal process are satisfied (step S240). The conditions are the same as those in the first removal process. When it is determined that the conditions for performing the deposit removal process are satisfied, the high-pressure pump 18 is driven so that the high-pressure side fuel pressure Pfd becomes the threshold value Pref2, and fuel is injected from the in-cylinder injection valve 29 at 100% (step S250). By injecting fuel from the in-cylinder injection valve 29 with the high-pressure side fuel pressure Pfd set to the threshold value Pref2, the thermosetting deposits that have adhered and accumulated near the tip of the in-cylinder injection valve 29 are removed. In the removal process of step S250 (second removal process), the high pressure fuel pressure Pfd is set to a threshold value Pref2, which is greater than the threshold value Pref1, so that not only thermosetting deposits are removed but also thermoplastic deposits are removed. The second removal process continues until the second counter Ch reaches a value of 0 and the second removal flag Fch is set to a value of 0. If the driver depresses the accelerator pedal while the second removal process is being performed and the conditions for performing the deposit removal process are no longer met, the second removal process is interrupted, but is resumed when the conditions for performing the deposit removal process are subsequently met. If the second removal flag Fch is set to a value of 1, the second removal process is performed regardless of the value of the first removal flag Fcs.

In the engine device 10 of the embodiment described above, when the first counter Cs, which reflects the amount of thermoplastic deposits adhering and accumulating near the tip of the in-cylinder injection valve 29, reaches or exceeds the threshold Cref1, the fuel pressure Pfd of the high-pressure supply pipe 19 is set to or above the threshold Pref1 and fuel is injected from the in-cylinder injection valve 29 to perform a thermoplastic deposit removal process (first removal process). Also, when the second counter Ch, which reflects the amount of thermosetting deposits adhering and accumulating near the tip of the in-cylinder injection valve 29, reaches or exceeds the threshold Cref2, the fuel pressure Pfd of the high-pressure supply pipe 19 is set to or above the threshold Pref2 and fuel is injected from the in-cylinder injection valve 29 to perform a thermosetting deposit removal process (second removal process). In this way, by performing the thermoplastic deposit removal process and the thermosetting deposit removal process using the first counter Cs and the second counter Ch, the deposits accumulated in the in-cylinder injection valve 29 can be more appropriately removed.

In the engine device 10 of the embodiment, the first counter Cs is incremented when the condition that the fuel injection from the port injection valve 28 is 100% is satisfied, with the cooling water temperature Tw being equal to or higher than the threshold value Tref1. However, the first counter Cs may be incremented appropriately according to the operating conditions of the engine 12, as long as it reflects the amount of thermoplastic deposits that adhere to and accumulate near the tip of the in-cylinder injection valve 29. Also, the second counter Ch is incremented when the condition that the fuel injection from the port injection valve 28 is not 100% and the condition that the tip temperature Test of the in-cylinder injection valve 29 is equal to or higher than the threshold value Tref2 are satisfied, with the cooling water temperature Tw being equal to or higher than the threshold value Tref1. However, the second counter Ch may be incremented appropriately according to the operating conditions of the engine 12, as long as it reflects the amount of thermosetting deposits that adhere to and accumulate near the tip of the in-cylinder injection valve 29.

In the engine device 10 of the embodiment, the first removal process and the second removal process are performed using a first counter Cs that reflects the amount of thermoplastic deposits that adhere to and accumulate near the tip of the in-cylinder injection valve 29, and a second counter Ch that reflects the amount of thermosetting deposits that adhere to and accumulate near the tip of the in-cylinder injection valve 29. However, counters may not be used to set the removal timing of thermoplastic deposits that adhere to and accumulate near the tip of the in-cylinder injection valve 29 and the removal timing of thermosetting deposits. For example, the fuel pressure Pfd of the high-pressure supply pipe 19 may be set to a threshold value Pref1 or higher and fuel may be injected from the in-cylinder injection valve 29 every time a first predetermined period has elapsed, and the thermosetting deposits may be removed by injecting fuel from the in-cylinder injection valve 29 with the fuel pressure Pfd of the high-pressure supply pipe 19 set to a threshold value Pref2 or higher every time a second predetermined period has elapsed.

In the engine device 10 of the embodiment, the engine 12 used is one in which the in-cylinder injection valve 29 is located 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 located on the side wall (side) of the combustion chamber 31.

In the engine device 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.

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 explained. 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", and the electronic control unit 70 corresponds to the "control device".

The correspondence between the main elements of the Examples and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the Examples are examples for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving 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 Means for Solving the Problem column.

The above describes the form for carrying out the present invention using examples, but 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 invention.

The present invention can be used in the engine equipment manufacturing industry, etc.

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 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 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 port injection valve, 29 in-cylinder injection valve, 29a fuel pressure sensor, 30 intake valve, 31 combustion chamber, 32 spark plug, 33 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.

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 control device for controlling the engine and the fuel supply device;
An engine device comprising:
The control device includes:
a first counter that counts up when all of the following conditions are met: a cooling water temperature of the engine is equal to or higher than a water temperature threshold, a fuel pressure in the high-pressure supply pipe is less than a first fuel pressure threshold, and fuel injection from the port injection valve is 100%; and that counts down when all of the following conditions are met: the fuel pressure in the high-pressure supply pipe is equal to or higher than the first fuel pressure threshold, and fuel injection from the port injection valve is not 100%; and when a first counter is equal to or higher than a first counter threshold, it is estimated that a thermoplastic deposit has accumulated in the in-cylinder injection valve,
a second counter that counts up when all of the following conditions are met: a cooling water temperature of the engine is equal to or higher than a water temperature threshold, a tip temperature of the in-cylinder injection valve is equal to or higher than a tip temperature threshold, and the fuel pressure in the high-pressure supply pipe is less than a second fuel pressure threshold, and that counts down when all of the following conditions are met: the fuel pressure in the high-pressure supply pipe is equal to or higher than the second fuel pressure threshold, and fuel injection from the port injection valve is not 100%; and when the second counter is equal to or higher than a second counter threshold, it is estimated that a thermosetting deposit has accumulated in the in-cylinder injection valve,
when it is estimated that a thermoplastic deposit has accumulated in the cylinder injection valve, a first removal process is performed in which the fuel pressure in the high-pressure supply pipe is increased to a first predetermined pressure or higher to inject fuel from the cylinder injection valve, thereby removing the thermoplastic deposit;
when it is estimated that a thermosetting deposit has accumulated in the cylinder injection valve, a second removal process is performed in which the fuel pressure in the high-pressure supply pipe is increased to a second predetermined pressure or higher, which is higher than the first predetermined pressure, and fuel is injected from the cylinder injection valve to remove the thermosetting deposit.
An engine device characterized by:

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