JP7803302B2 - Engine equipment - Google Patents

Description

This disclosure relates to an engine device, and more particularly to an engine device that includes an engine with an in-cylinder injection valve and a control device that controls the engine.

Conventionally, one engine device proposed for this type is one that performs a process to regenerate a gasoline particulate filter (GPF) attached to the engine's exhaust system when the amount of accumulated particulates in the GPF becomes large (see, for example, Patent Document 1). In this device, when regenerating the GPF, combustion of the air-fuel mixture in some of the multiple cylinders is stopped, and when combustion of the air-fuel mixture in the other cylinders is performed, the air-fuel ratio is made richer than the stoichiometric air-fuel ratio, thereby performing a temperature increase process to remove particulate matter (PM) that has accumulated in the GPF.

Japanese Patent Application Laid-Open No. 2022-076163

In engines with direct injection valves, if the engine is frequently stopped before warm-up is complete, the amount of fuel diluted in the oil increases, which can lead to intermittent engine operation being prohibited and the aforementioned GPF heating process being prohibited. When the oil is changed, the oil dilution by fuel is eliminated and the prohibition on the GPF heating process is lifted. However, if the oil is not changed correctly, the GPF may overheat if the prohibition on the GPF heating process is lifted and the heating process is performed even though the oil dilution by fuel has not been eliminated.

The engine system disclosed herein is primarily intended to ensure that fuel dilution is eliminated after an oil change.

The engine device disclosed herein employs the following measures to achieve the above-mentioned primary objective.

The engine device of the present disclosure comprises:
An engine device including an engine having an in-cylinder injection valve and a control device that controls the engine,
When a request for resetting an estimated value of oil dilution by fuel is made based on an oil change, the control device determines whether or not dilution by fuel has been eliminated based on a learned value in air-fuel ratio learning and/or a correction value in feedback control of the air-fuel ratio, and resets the estimated value of dilution when it is determined that dilution has been eliminated.
It is characterized by:

In the engine device disclosed herein, when a request is made to reset the estimated oil dilution value due to an oil change, a dilution elimination determination is made to determine whether the oil dilution has been eliminated based on the learned value in air-fuel ratio learning and the correction value in air-fuel ratio feedback control. This makes it possible to confirm that fuel dilution has been eliminated after an oil change. Then, if it is determined that dilution has been eliminated, the dilution estimate value is reset. This allows the dilution estimate value to be reset more appropriately.

In the engine system of the present disclosure, when a history of air-fuel ratio learning exists for a high intake air volume region of the engine's operating range, where the intake air volume is relatively large, the control device may perform the dilution elimination determination based on the difference between the sum of the learned value of the air-fuel ratio learning for a low intake air volume region, where the intake air volume is relatively small, and the feedback control correction value, and the learned value of the air-fuel ratio learning for the high intake air volume region according to the history. In the high intake air volume region, the influence of fuel dilution is small, so the learned value of the air-fuel ratio learning does not change significantly depending on whether fuel dilution has been eliminated. On the other hand, in the low intake air volume region, the influence of fuel dilution is large, so the learned value of the air-fuel ratio learning changes significantly depending on whether fuel dilution has been eliminated. Therefore, if the sum of the learned value of the air-fuel ratio learning for the low intake air volume region and the feedback control correction value minus the learned value of the air-fuel ratio learning for the high intake air volume region is equal to or greater than a threshold, it can be determined that fuel dilution has been eliminated. If the sum is less than the threshold, it can be determined that fuel dilution has not been eliminated. In such an engine system, when there is no history of air-fuel ratio learning for the high intake air volume region, the control device may perform the dilution elimination determination based on the correction value and the learned value of air-fuel ratio learning for the low intake air volume region, where the intake air volume is relatively small. Since the sum of the learned value and the correction value of air-fuel ratio learning for the low intake air volume region corresponds to the actual air-fuel ratio, it is possible to determine whether fuel dilution has been eliminated by comparing the actual air-fuel ratio with a threshold value.

In the engine device disclosed herein, the reset request is made based on the dealer operating a switch for an oil change or resetting the mileage after the oil change, and a different threshold value may be used for the dilution elimination determination when a reset request is made based on the switch operation and the dilution elimination determination when a reset request is made based on the reset operation. For example, if the dilution elimination determination is made based on the difference between the learned value of the air-fuel ratio for the high intake air volume region and the learned value of the air-fuel ratio for the low intake air volume region, the same or different threshold value may be used for the determination threshold value compared with the difference. This means that a fuel dilution determination can be made based on the cause of the reset request.

In the engine system of the present disclosure, if the control device determines in the dilution elimination determination that the dilution has not been eliminated to a small extent, the control device may extend the period for the dilution elimination determination until the cumulative intake air volume after starting the engine reaches a predetermined air volume. This allows for a more accurate determination of whether fuel dilution has been eliminated.

1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with an engine device according to an embodiment of the present disclosure. 1 is a diagram showing an outline of the configuration of an engine 22 mounted on a hybrid vehicle 20. FIG. 4 is a flowchart showing an example of a fuel dilution amount reset process executed by an engine ECU 24.

Next, an embodiment of the present disclosure will be described. Figure 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with an engine device according to an embodiment of the present disclosure. Figure 2 is a schematic diagram showing the configuration of an engine 22 equipped in the hybrid vehicle 20. The hybrid vehicle 20 of this embodiment includes the engine 22, a motor 30, an inverter 32, a clutch K0, an automatic transmission 40, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

The engine 22 is a six-cylinder internal combustion engine fueled by gasoline. As shown in Figure 2, the engine 22 has port injection valves 126 that inject fuel into the intake ports and in-cylinder injection valves 127 that inject fuel into the cylinders. It operates in one of three modes: port injection mode, in-cylinder injection mode, and combined injection mode. In port injection mode, air from the air cleaner 122 is drawn into the intake pipe 123 and passes through the throttle valve 124 and surge tank 125. Fuel is injected from the port injection valve 126 downstream of the surge tank 125 into the intake pipe 123, mixing the air and fuel. This mixture is drawn into the combustion chamber 129 via the intake valve 128 and combusted explosively by an electric spark generated by the spark plug 130. The resulting energy pushes down the pistons 132 within the cylinder bores, converting their reciprocating motion into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is drawn into the combustion chamber 129, and fuel is injected from the in-cylinder injection valve 127 during the intake stroke or compression stroke. The fuel is then explosively combusted by an electric spark from the spark plug 130, generating rotational motion of the crankshaft 23. In the shared injection mode, fuel is injected from both the port injection valve 126 and the in-cylinder injection valve 127. Exhaust gas discharged from the combustion chamber 129 via an exhaust valve 133 into an exhaust pipe 134 is then discharged via a purification device 135 and a gasoline particulate filter (hereinafter referred to as "GPF") 136. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components in the exhaust, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). The GPF 136 is formed as a porous filter using ceramics, stainless steel, or other materials, and captures particulate matter (PM) such as soot in the exhaust gas. Instead of the GPF 136, a four-way catalyst may be used, which combines the purification function of a three-way catalyst with the function of capturing particulate matter.

The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24. The engine ECU 24 receives, for example, a crank angle θcr from a crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and a coolant temperature Tw from a water temperature sensor 142 that detects the temperature of the coolant for the engine 22. The engine ECU 24 also receives as inputs the cam angles θci and θco from a cam position sensor 144 that detects the rotational position of the intake camshaft that opens and closes the intake valve 128 and the exhaust camshaft that opens and closes the exhaust valve 133, the throttle opening TH from a throttle valve position sensor 124a that detects the position of the throttle valve 124, the intake air amount Qa from an air flow meter 123a attached to the intake pipe 123 upstream of the throttle valve 124, the intake air temperature Ta from a temperature sensor 123t attached to the intake pipe 123 upstream of the throttle valve 124, and the surge pressure Ps from a pressure sensor 125a attached to the surge tank 125. Furthermore, the engine ECU 24 also receives input of a front air-fuel ratio AF1 from a front air-fuel ratio sensor 137 attached upstream of the purification device 135 in the exhaust pipe 134, a rear air-fuel ratio AF2 from a rear air-fuel ratio sensor 138 attached between the purification device 135 in the exhaust pipe 134 and the GPF 136, and a differential pressure ΔP from a differential pressure sensor 136a that detects the differential pressure before and after the GPF 136 (the differential pressure between the upstream and downstream sides).

The engine ECU 24 outputs, for example, a control signal to the throttle valve 124, a control signal to the port injection valve 126, a control signal to the in-cylinder injection valve 127, and a control signal to the spark plug 130.

The engine ECU 24 calculates the engine 22 rotation speed Ne based on the engine 22 crank angle θcr from the crank position sensor 140. The engine ECU 24 also calculates the load factor KL (the ratio of the volume of air actually taken in per cycle to the stroke volume per cycle of the engine 22) based on the intake air volume Qa from the air flow meter 123a and the engine 22 rotation speed Ne. The engine ECU 24 also calculates the PM accumulation amount Qpm, which is the amount of particulate matter accumulated in the GPF 136, based on the differential pressure ΔP from the differential pressure sensor 136a, and calculates the filter temperature tf, which is the temperature of the GPF 136, based on the engine 22 rotation speed Ne and the load factor KL. The engine ECU 24 also calculates the fuel dilution amount Fd, which is an estimate of the amount of dilution of the oil used as lubricating oil for the engine 22 with fuel, based on the coolant temperature Tw at the time of engine 22 startup and the integrated value of the intake air volume until the coolant temperature Tw reaches 40°C after startup. The fuel dilution amount Fd increases when the engine 22 is frequently stopped before warm-up is complete.

As shown in FIG. 1, a starter motor 25 for cranking the engine 22 and an alternator 26 for generating electricity using power from the engine 22 are connected to the crankshaft 23 of the engine 22. The starter motor 25 and alternator 26, along with a low-voltage battery 62, are connected to a low-voltage power line 63 and are controlled by the HVECU 70.

The motor 30 is configured as a synchronous generator-motor. The rotating shaft 31, to which the rotor of the motor 30 is fixed, is connected to the crankshaft 23 of the engine 22 via a clutch K0 and to the input shaft 41 of the automatic transmission 45. The inverter 32 is used to drive the motor 30 and is connected to a high-voltage power line 61. The motor 30 is driven by a motor electronic control unit (hereinafter referred to as the "motor ECU") 34, which controls the switching of multiple switching elements of the inverter 32. The motor ECU 34 receives inputs such as a rotational position θmg from a rotational position sensor 30a that detects the rotational position of the rotor (rotating shaft 31) of the motor 30, and phase currents Iu and Iv from current sensors that detect the phase currents of each phase of the motor 30, and outputs control signals to the inverter 32. The motor ECU 34 calculates the rotational speed Nmg of the motor 30 based on the rotational position θmg of the rotor (rotating shaft 31) of the motor 30 from the rotational position sensor 30a.

The clutch K0 is configured, for example, as a hydraulically driven friction clutch and is controlled by the HVECU 70 to connect and disconnect the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30.

The automatic transmission 40 includes a torque converter 43 and, for example, a six-speed automatic transmission 45. The torque converter 43 is configured as a typical fluid power transmission device and amplifies the torque transmitted from the input shaft 41 connected to the rotating shaft 31 of the motor 30 to the transmission input shaft 44, which is the input shaft of the automatic transmission 45, or transmits the torque directly without amplifying it. The automatic transmission 45 includes the transmission input shaft 44, an output shaft 42 connected to the drive wheels 49 via a differential gear 48, multiple planetary gears, and multiple hydraulically driven friction engagement elements (clutches and brakes). The automatic transmission 45 transmits power between the transmission input shaft 44 and the output shaft 42, establishing forward gears (first through sixth) and reverse gears by engaging and disengaging the multiple friction engagement elements. The hydraulic pressure of hydraulic oil from a mechanical oil pump or an electric oil pump is adjusted and supplied to the clutch K0 and automatic transmission 45 by a hydraulic control device (not shown).

The high-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or nickel-metal hydride secondary battery with a rated voltage of several hundred volts, and is connected to the high-voltage power line 61 together with the inverter 32. The low-voltage battery 62 is configured as, for example, a lead-acid battery with a rated voltage of approximately 12 or 14 volts, and is connected to the low-voltage power line 63 together with the starter motor 25 and alternator 26. The DC/DC converter 64 is connected to the high-voltage power line 61 and the low-voltage power line 63. This DC/DC converter 64 supplies power from the high-voltage power line 61 to the low-voltage power line 63 while stepping down the voltage.

The HVECU 70 is configured as a microcomputer. For example, the HVECU 70 inputs the rotation speed Nin from the rotation speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotation speed Nmi from the rotation speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotation speed Nout from the rotation speed sensor 42a attached to the output shaft 42 of the automatic transmission 40. The HVECU 70 also inputs the voltage Vbh of the high-voltage battery 60 from a voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from a current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from a voltage sensor attached between the terminals of the low-voltage battery 62. Additionally, the HVECU 70 receives as input an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87.

The HVECU 70 outputs control signals to the starter motor 25, the alternator 26, the clutch K0 and the automatic transmission 40 (hydraulic control device), and the DC/DC converter 64. The HVECU 70 communicates with the engine ECU 24 and the motor ECU 34. The HVECU 70 calculates the rotation speed ratio Gt of the automatic transmission 40 by dividing the rotation speed Nin of the input shaft 41 of the automatic transmission 40 from the rotation speed sensor 41a by the rotation speed Nout of the output shaft 42 of the automatic transmission 40 from the rotation speed sensor 42a.

Next, we will explain the operation of the engine device installed in the hybrid vehicle 20 of this embodiment, particularly the operation when resetting the fuel dilution amount Fd, which is an estimated value for the amount of oil dilution by fuel. Figure 3 is a flowchart showing an example of the fuel dilution amount reset process executed by the engine ECU 24. This process is performed when the engine 22 is started after a request to reset the fuel dilution amount Fd has been made. A reset request is made when a dealer sets a reset request flag Fr when an oil change is performed at a dealer. A reset request is also made when a user inputs information into the oil mileage system. The oil mileage system notifies the user to change the oil when a predetermined mileage has been reached since the oil change, and the user responds to this notification by inputting that the oil has been changed. Therefore, the reason the fuel dilution amount reset process is performed after an oil change is because the oil change eliminates the dilution of the oil with fuel.

When the fuel dilution amount reset process is executed, the engine ECU 24 first determines whether the request to reset the fuel dilution amount Fd is from the dealer or due to oil mileage (step S100). If the reset request is from the dealer, the threshold value AFref1 is set to value A11 and the threshold value AFref2 is set to value A12 (step S110). If the reset request is due to oil mileage, the threshold value AFref1 is set to value A21, which is slightly larger than value A11, and the threshold value AFref2 is set to value A22, which is larger than value A12 (step S120). The threshold values AFref1 and AFref2 are used in the dilution cancellation determination, which will be described later.

Next, the engine 22 is operated continuously for a certain period of time in the low intake air volume range (low GA) (step S130), and purge cut is performed (step S140). The low intake air volume range is a relatively low-speed, low-load operating range of the engine 22. This certain period is a period during which the oil temperature is above a predetermined temperature (e.g., 40°C or 45°C) and the cumulative value ΣQa of the intake air volume Qa since the start of the engine 22 is above a predetermined value (the amount of air required for the oil temperature to reach the predetermined temperature under normal conditions). The reason for operating the engine 22 continuously for a certain period of time in the low intake air volume range (low GA) is to volatilize the diluted fuel even if the oil change is insufficient. The reason for operating the engine 22 in the low intake air volume range is that the impact of oil dilution by fuel is significant in this range.

Then, after waiting for the completion of air-fuel ratio learning in the low intake air volume region (step S150), a dilution cancellation determination (steps S160-S220) is made. The dilution cancellation determination first determines whether there is a history of air-fuel ratio learning in the high intake air volume region (step S160). The high intake air volume region is a relatively high-speed, high-load operating region of the engine 22. If it is determined that there is a history of air-fuel ratio learning in the high intake air volume region, the learned value AF1 of the air-fuel ratio learning in the high intake air volume region, the learned value AF2 of the air-fuel ratio learning in the low intake air volume region, and the correction value k for the air-fuel ratio feedback control are input (step S180), and it is determined whether the sum of the learned value AF2 and the correction value k minus the learned value AF1 is equal to or greater than the threshold value AFref1 (step S180). In the high intake air volume region, the influence of oil dilution by fuel is small, so the learned value AF1 remains the same regardless of whether the oil is diluted by fuel. On the other hand, in the low intake air volume region, the influence of oil dilution by fuel is large, so the learned value AF2 changes significantly depending on whether the oil is diluted by fuel. Therefore, when the oil change is performed properly, the learned value AF2 of the air-fuel ratio learning in the low intake air volume region will be approximately the same as the learned value AF1 of the air-fuel ratio learning in the high intake air volume region, so the sum of the learned value AF2 and the correction value k minus the learned value AF1 ((AF2+k)-AF1) will be a large value. On the other hand, if the oil change has not been performed properly, the learned value AF2 of the air-fuel ratio learning in the low intake air volume region will be different from the learned value AF1 of the air-fuel ratio learning in the high intake air volume region, and therefore the value obtained by subtracting the learned value AF1 from the sum of the learned value AF2 and the correction value k ((AF2+k)-AF1)) will be small. Therefore, whether the oil dilution by fuel has been eliminated can be determined based on whether the value obtained by subtracting the learned value AF1 from the sum of the learned value AF2 and the correction value k ((AF2+k)-AF1)) is large or small. The threshold value AFref1 set in steps S100 to S120 is used to determine whether the oil has been dilution-eliminated. When the reset request is made by a dealer, it can be assumed that the oil change is performed more properly than when the oil is changed by a user, so the threshold value AFref1 can be set to a smaller value than when the reset request is made based on oil mileage. In the embodiment, value A11 is smaller than value A21, but values A11 and A21 may be the same value. In step S180, it is determined whether the sum of learned value AF2 and correction value k minus learned value AF1 is greater than or equal to threshold value AFref1, but it may also be determined whether the sum of learned value AF2 minus learned value AF1 is greater than or equal to the threshold value.

If it is determined in step S180 that the sum of the learned value AF2 and the correction value k minus the learned value AF1 is equal to or greater than the threshold value AFref1, the fuel dilution amount Fd is reset to 0, the air-fuel ratio learning history is cleared (step S230), and the process ends.

If it is determined in step S180 that the sum of the learned value AF2 and the correction value k minus the learned value AF1 is less than the threshold value AFref1, it is determined whether the sum of the learned value AF2 and the correction value k minus the learned value AF1, and then the threshold value AFref1 is further subtracted from that ({(AF2+k)-AF1}-AFref1) is greater than or equal to the threshold value Aref (step S190). This determination determines whether the sum of the learned value AF2 and the correction value k minus the learned value AF1 is slightly less than the threshold value AFref1, and therefore whether dilution elimination was slightly prevented. Therefore, a relatively small value can be used for the threshold value Aref. If it is determined that dilution elimination has not been achieved by a small amount, the dilution elimination determination is performed based on the sum of the learned value AF2 and the correction value k of the air-fuel ratio learning for the low intake air volume region in steps S150 to S200, minus the learned value AF1 of the air-fuel ratio learning for the high intake air volume region, until the integrated value ΣQa of the intake air volume Qa since the start of the engine 22 reaches the predetermined value Qref. If it is determined in step S190 that the sum of the learned value AF2 and the correction value k minus the learned value AF1, and then further subtract the threshold value AFref1 ({(AF2+k)-AF1}-AFref1) is less than the threshold value Aref, that is, if it is determined that dilution elimination has not been achieved by a small amount, then the process ends without resetting the fuel dilution amount Fd to zero. Also, when it is determined in step S200 that the cumulative value ΣQa of the intake air volume Qa has reached the predetermined value Qref, the process ends without resetting the fuel dilution amount Fd to 0.

If step S160 determines that there is no history of air-fuel ratio learning in the high intake air volume region, the learned value AF2 from the air-fuel ratio learning in the low intake air volume region and the correction value k in the air-fuel ratio feedback control are input (step S210), and it is determined whether the sum of the learned value AF2 and the correction value k is equal to or greater than the threshold value AFref2 (step S220). Because the sum of the learned value AF2 and the correction value k is the actual air-fuel ratio, the determination in step S210 is whether the actual air-fuel ratio is equal to or greater than the threshold value AFref2. When an oil change is performed properly, oil dilution by fuel is eliminated, and the actual air-fuel ratio is close to the stoichiometric air-fuel ratio. On the other hand, when an oil change is not performed properly, oil dilution by fuel is not eliminated, and the actual air-fuel ratio differs from the stoichiometric air-fuel ratio. Therefore, threshold value AFref2 can be determined as a value within the allowable range of the actual air-fuel ratio relative to the stoichiometric air-fuel ratio when an oil change is performed properly. In the embodiment, value A12 is set to a value smaller than value A22, but values A12 and A22 may be the same value. If it is determined in step S220 that the actual air-fuel ratio is equal to or greater than threshold value AFref2, it is determined that oil dilution with fuel has been eliminated, and the fuel dilution amount Fd is reset to 0, the air-fuel ratio learning history is cleared (step S230), and this process ends. On the other hand, if it is determined in step S220 that the difference between the actual air-fuel ratio and the stoichiometric air-fuel ratio is less than threshold value AFref2, it is determined that oil dilution with fuel has not been eliminated, and this process ends without resetting fuel dilution amount Fd to 0.

In the engine device mounted on the hybrid vehicle 20 of the embodiment described above, in response to a request to reset the fuel dilution amount Fd, if there is a history of air-fuel ratio learning in the high intake air volume region, it is determined that oil dilution with fuel has been eliminated and the fuel dilution amount Fd is reset when the sum of the learned value AF2 of air-fuel ratio learning in the low intake air volume region and the correction value k in air-fuel ratio feedback control minus the learned value AF1 of air-fuel ratio learning in the high intake air volume region ((AF2 + k) - AF2)) is equal to or greater than the threshold value AFref1. Furthermore, if there is no history of air-fuel ratio learning in the high intake air volume region, the actual air-fuel ratio is calculated based on the sum of the learned value AF2 of air-fuel ratio learning in the low intake air volume region and the correction value k in air-fuel ratio feedback control, and it is determined that oil dilution with fuel has been eliminated and the fuel dilution amount Fd is reset when the actual air-fuel ratio is equal to or greater than the threshold value AFref2. This allows the fuel dilution amount Fd to be reset after confirming that the fuel dilution has been eliminated after an oil change. As a result, it is possible to prevent the fuel dilution amount Fd from being reset even when the oil change has not been performed properly, and it is possible to prevent the GPF 136 from overheating due to the regeneration process (temperature increase process) of the GPF 136 being performed when the fuel dilution amount Fd is large.

In the engine device mounted on the hybrid vehicle 20 of this embodiment, if there is a history of air-fuel ratio learning in the high intake air volume region and the dilution elimination determination is not made for a short time, the dilution elimination determination is made until the integrated value ΣQa of the intake air volume Qa since the start of the engine 22 reaches a predetermined value Qref. As a result, the dilution elimination determination can be made more accurately. Note that even when there is no history of air-fuel ratio learning in the high intake air volume region, the dilution elimination determination may be continued until the integrated value ΣQa of the intake air volume Qa since the start of the engine 22 reaches the predetermined value Qref.

The engine device in the embodiment is mounted on a hybrid vehicle 20, but it may also be mounted on a moving object other than a vehicle or incorporated into stationary equipment.

The following explains the correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section. In the embodiment, the engine 22 corresponds to the "engine" and the engine ECU 24 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" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, as the Examples are examples used to specifically explain the form for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the Examples are merely specific examples of the invention described in the "Means for Solving the Problem" section.

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 embodied in various forms without departing from the spirit of the present invention.

This invention can be used in industries such as engine equipment manufacturing.

20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 24 Engine ECU, 30 Motor, 32 Inverter, 34 Motor ECU, 40 Automatic transmission, 43 Torque converter, 44 Transmission input shaft, 45 Automatic transmission, 48 Differential gear, 49 Drive wheels, 60 High-voltage battery, 62 Low-voltage battery, 64 DC/DC converter, 70 HVECU.

Claims (5)

An engine device including an engine having an in-cylinder injection valve and a control device that controls the engine,
When a request for resetting an estimated value of oil dilution by fuel is made based on an oil change, the control device determines whether or not dilution by fuel has been eliminated based on a learned value in air-fuel ratio learning and/or a correction value in feedback control of the air-fuel ratio, and resets the estimated value of dilution when it is determined that dilution has been eliminated.
An engine device characterized by: 2. The engine device according to claim 1,
When there is a history of air-fuel ratio learning for a high intake air amount region of the engine operating range in which the intake air amount is relatively large, the control device makes the dilution elimination determination based on the sum of a learned value of air-fuel ratio learning for a low intake air amount region in which the intake air amount is relatively small and a feedback control correction value, and the difference between the learned value of air-fuel ratio learning for the high intake air amount region related to the history.
Engine equipment. 3. The engine device according to claim 2,
when there is no history of air-fuel ratio learning for the high intake air amount region, the control device makes the dilution cancellation determination based on a learned value of air-fuel ratio learning for a low intake air amount region in which the intake air amount is relatively small and the correction value.
Engine equipment. 2. The engine device according to claim 1,
The reset request is made based on the fact that a dealer has operated an oil change switch or that a reset operation of the mileage after the oil change has been performed,
A threshold value for determination is used for the dilution elimination determination when a reset request is made by the switch operation and for the dilution elimination determination when a reset request is made by the reset operation.
Engine equipment. An engine device according to any one of claims 1 to 4,
When the control device determines that the dilution has not been eliminated to a small extent in the dilution elimination determination, the control device extends the period of the dilution elimination determination until the integrated intake air amount after starting the engine reaches a predetermined air amount.
Engine equipment.