Engine equipment

Abstract

After an oil change, ensure that fuel dilution has been properly resolved. [Solution] The engine system comprises an engine and a control device for controlling the engine. When a reset request is made based on an oil change for the estimated oil dilution value by fuel, the control device sets a threshold value for determination which tends to increase as the intake air volume increases, and determines whether or not the oil dilution by fuel has been resolved by checking whether or not the fuel injection correction value in the air-fuel ratio feedback control is equal to or greater than the determination threshold value, and resets the estimated oil dilution value when it is determined that the dilution has been resolved.

Description

Technical Field

[0001] The present disclosure relates to an engine device, and more particularly to an engine device including an engine and a control device for controlling the engine.

Background Art

[0002] Conventionally, as this type of engine device, when the amount of deposits in a GPF (gasoline particulate filter) attached to the exhaust system of an engine increases, a process for regenerating the GPF has been proposed (for example, see Patent Document 1). In this device, when regenerating the GPF, combustion of the air-fuel mixture in some of the plurality of cylinders is stopped, and at the same time, when the air-fuel mixture in other cylinders burns, the air-fuel ratio is made richer than the theoretical air-fuel ratio to perform a temperature-raising process for removing particulate matter (PM) deposited on the GPF.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an engine having an in-cylinder injection valve, if the engine operation is frequently stopped before warm-up is completed, the fuel diluted in the oil increases, and the intermittent operation of the engine may be prohibited, or the above-described temperature-raising process of the GPF may be prohibited. When an oil change is performed, the dilution of the oil by the fuel is eliminated, and the prohibition of the temperature-raising process of the GPF and the like is also released. However, if the oil change is not correctly performed, and the temperature-raising process of the GPF is released and the temperature-raising process is performed even though the dilution of the oil by the fuel has not been eliminated, the GPF may overheat.

[0005] The primary purpose of the engine device disclosed herein is to more properly verify the elimination of fuel dilution after an oil change. [Means for solving the problem]

[0006] The engine device of this disclosure employs the following means to achieve the main objective described above.

[0007] The engine device of this disclosure, An engine system comprising an engine and a control device for controlling the engine, When a reset request is made based on an oil change for the estimated oil dilution value by fuel, the control device sets a determination threshold that tends to increase as the intake air volume increases, and determines whether the dilution of oil by fuel has been resolved based on whether the fuel injection correction value in the air-fuel ratio feedback control is equal to or greater than the determination threshold. If it is determined that the dilution has been resolved, the control device resets the estimated oil dilution value. It is characterized by the following:

[0008] In the engine system of this disclosure, when a reset request is made based on an oil change for the estimated oil dilution value due to fuel, a determination threshold is set so that it tends to increase as the intake air volume increases, and a determination of whether or not oil dilution due to fuel has been resolved is made based on whether or not the fuel injection correction value in the air-fuel ratio feedback control is equal to or greater than the determination threshold. Since a small determination threshold is set in the region where the intake air volume, which has a large effect of dilution, is relatively small, the resolution of fuel dilution after an oil change can be confirmed more appropriately even in the region where the intake air volume is small. When it is determined that dilution has been resolved, the estimated dilution value is reset. This makes it possible to reset the estimated dilution value more appropriately.

[0009] In the engine device of this disclosure, the determination threshold may be set to increase in one or two steps within a relatively small range of intake air volume. If it increases in one step, a small predetermined value is set as the determination threshold when the intake air volume is less than a predetermined air volume, and a large predetermined value is set as the determination threshold when the intake air volume is equal to or greater than the predetermined air volume. If it increases in two steps, a small first predetermined value is set as the determination threshold when the intake air volume is less than a first predetermined air volume, a second predetermined value greater than the first predetermined value is set as the determination threshold when the intake air volume is equal to or greater than the first predetermined air volume but less than a second predetermined air volume, and a third predetermined value greater than the second predetermined value is set as the determination threshold when the intake air volume is equal to or greater than the second predetermined air volume. The determination threshold may also be set to increase steplessly with respect to the magnitude of the intake air volume. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with an engine system as an embodiment of the present disclosure. [Figure 2] This is a schematic diagram showing the general configuration of the engine 22 installed in the hybrid vehicle 20. [Figure 3] This flowchart shows an example of the fuel dilution reset process performed by the engine ECU24. [Figure 4] This is an explanatory diagram showing the relationship between the intake air volume Qa, the fuel injection correction rate Fk after oil change, and the judgment threshold Fref. [Figure 5] This is an explanatory diagram showing the relationship between the intake air volume Qa, the fuel injection correction rate Fk after oil change, and the determination threshold Fref in a modified example. [Modes for carrying out the invention]

[0011] Next, embodiments 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 as an embodiment of the present disclosure. Figure 2 is a schematic diagram showing the configuration of an engine 22 mounted on the hybrid vehicle 20. The hybrid vehicle 20 of the embodiment comprises an 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.

[0012] Engine 22, configured as a 6-cylinder internal combustion engine using gasoline as fuel, has, as shown in Figure 2, a port injection valve 126 that injects fuel into the intake port and an in-cylinder injection valve 127 that injects fuel into the cylinder, and operates in one of three modes: port injection mode, in-cylinder injection mode, or shared injection mode. In port injection mode, air from the air cleaner 122 is drawn into the intake manifold 123, passes through the throttle valve 124 and surge tank 125, and fuel is injected from the port injection valve 126 downstream of the surge tank 125 in the intake manifold 123 to mix the air and fuel. This mixture is drawn into the combustion chamber 129 via the intake valve 128, and is combusted by an electric spark from the spark plug 130, converting the reciprocating motion of the piston 132, which is pushed down by the energy within the cylinder bore, into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is drawn into the combustion chamber 129, fuel is injected from the in-cylinder injection valve 127 during the intake and compression strokes, and the fuel is combusted explosively by an electric spark from the spark plug 130 to obtain rotational motion of the crankshaft 23. In the shared injection mode, fuel injection from the port injection valve 126 and fuel injection from the in-cylinder injection valve 127 are shared. The exhaust gas discharged from the combustion chamber 129 to the exhaust pipe 134 via the exhaust valve 133 is discharged through a purification device 135 and a gasoline particulate filter (GPF) 136. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) in the exhaust gas. The GPF 136 is formed as a porous filter using ceramics or stainless steel, and collects particulate matter (PM) such as soot in the exhaust gas. Alternatively, instead of GPF136, a four-way catalyst combining the purification function of a three-way catalyst with the particulate matter collection function may be used.

[0013] The engine 22 is controlled by an electronic engine control unit (hereinafter referred to as "engine ECU") 24. The engine ECU 24 receives, for example, the crank angle θcr from a crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and the coolant temperature Tw from a water temperature sensor 142 that detects the temperature of the coolant in the engine 22. The engine ECU24 also receives input from the cam position sensor 144, which detects the rotational position of the intake camshaft that opens and closes the intake valve 128 and the rotational position of the exhaust camshaft that opens and closes the exhaust valve 133, the throttle opening TH from the throttle valve position sensor 124a, which detects the position of the throttle valve 124, the intake air volume Qa from the airflow meter 123a installed upstream of the throttle valve 124 in the intake manifold 123, the intake air temperature Ta from the temperature sensor 123t installed upstream of the throttle valve 124 in the intake manifold 123, and the surge pressure Ps from the pressure sensor 125a installed in the surge tank 125. Furthermore, the engine ECU 24 also receives input from the front air-fuel ratio AF1 from the front air-fuel ratio sensor 137, which is mounted upstream of the exhaust pipe 134's purification device 135, the rear air-fuel ratio AF2 from the rear air-fuel ratio sensor 138, which is mounted between the exhaust pipe 134's purification device 135 and the GPF 136, and the differential pressure ΔP from the differential pressure sensor 136a, which detects the differential pressure across the GPF 136 (the differential pressure between the upstream and downstream sides).

[0014] The engine ECU24 outputs, for example, control signals to the throttle valve 124, the port injection valve 126, the in-cylinder injection valve 127, and the spark plug 130.

[0015] The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140. The engine ECU 24 also calculates the load factor (the ratio of the volume of air actually inhaled in one cycle to the stroke volume per cycle of the engine 22) KL based on the intake air volume Qa from the airflow meter 123a and the rotational speed Ne of the engine 22. Furthermore, the engine ECU 24 calculates the PM deposit amount Qpm as the amount of particulate matter deposited on the GPF 136 based on the differential pressure ΔP from the differential pressure sensor 136a, and calculates the filter temperature tf as the temperature of the GPF 136 based on the rotational speed Ne of the engine 22 and the load factor KL. In addition, the engine ECU 24 calculates the fuel dilution amount Fd as an estimate of the amount of oil diluted by fuel as the lubricant of the engine 22, based on the coolant temperature Tw at the start of the engine 22 and the cumulative amount of intake air until the coolant temperature Tw reaches 40°C after starting. The fuel dilution amount Fd increases due to the frequent stopping of engine 22 before warm-up is complete.

[0016] As shown in Figure 1, the crankshaft 23 of the engine 22 is connected to a starter motor 25 for cranking the engine 22 and an alternator 26 that generates electricity using power from the engine 22. The starter motor 25 and alternator 26 are connected to a low-voltage power line 63 along with a low-voltage battery 62 and are controlled by the HVECU 70.

[0017] 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 is also connected to the input shaft 41 of the automatic transmission 45. The inverter 32 is used to drive the motor 30 and is connected to the high-voltage power line 61. The motor 30 is rotationally driven by the switching control of multiple switching elements of the inverter 32 by the motor electronic control unit (hereinafter referred to as "motor ECU") 34. The motor ECU 34 receives input such as the 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 the phase currents Iu, 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.

[0018] Clutch K0 is configured, for example, as a hydraulically driven friction clutch, controlled by HVECU 70, and connects and disconnects the crankshaft 23 of engine 22 from the rotating shaft 31 of motor 30.

[0019] The automatic transmission 40 has a torque converter 43 and an automatic transmission 45 with, for example, six forward speeds. The torque converter 43 is configured as a general fluid transmission device, and transmits the power of the input shaft 41 connected to the rotating shaft 31 of the motor 30 to the input shaft of the automatic transmission 45, i.e., the transmission input shaft 44, with torque amplification, or transmits it as it is without torque amplification. The automatic transmission 45 has a transmission input shaft 44, an output shaft 42 connected to the drive wheels 49 via a differential gear 48, a plurality of planetary gears, and a plurality of hydraulically driven friction engagement elements (clutches, brakes). The automatic transmission 45 forms forward and reverse gears from the first speed to the sixth speed by engaging and disengaging the plurality of friction engagement elements, and transmits power between the transmission input shaft 44 and the output shaft 42. The clutch K0 and the automatic transmission 45 are supplied with hydraulic pressure of the working oil from a mechanical oil pump or an electric oil pump, which is regulated by a hydraulic control device (not shown).

[0020] The high-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery with a rated voltage of about several hundred volts, and is connected to the high-voltage side 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 about 12V or 14V, and is connected to the low-voltage side power line 63 together with the starter motor 25 and the alternator 26. The DC / DC converter 64 is connected to the high-voltage side power line 61 and the low-voltage side power line 63. This DC / DC converter 64 supplies the power of the high-voltage side power line 61 to the low-voltage side power line 63 with voltage reduction.

[0021] The HVECU 70 is configured as a microcomputer. The HVECU 70 inputs, for example, the rotational speed Nin from the rotational speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotational speed Nmi from the rotational speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotational speed Nout from the rotational 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 the voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from the current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from the voltage sensor attached between the terminals of the low-voltage battery 62. Further, the HVECU 70 inputs the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed V from the vehicle speed sensor 87.

[0022] 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), the control signal to the DC / DC converter 64, etc. The HVECU 70 communicates with the engine ECU 24 and the motor ECU 34. The HVECU 70 calculates the rotational speed ratio Gt of the automatic transmission 40 by dividing the rotational speed Nin of the input shaft 41 of the automatic transmission 40 from the rotational speed sensor 41a by the rotational speed Nout of the output shaft 42 of the automatic transmission 40 from the rotational speed sensor 42a.

[0023] Next, we will explain the operation of the engine system installed in the hybrid vehicle 20 of the embodiment, particularly the operation when resetting the fuel dilution amount Fd, which is an estimated value of the amount of oil diluted by fuel. Figure 3 is a flowchart showing an example of the fuel dilution amount reset process performed 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. The reset request is made when the dealer sets the reset request flag Fr when the oil has been changed at the dealer, or when the user makes an input to the oil mileage system. The oil mileage system is a system that notifies the user to change the oil when the mileage since the last oil change reaches a predetermined distance, and the user inputs that the oil has been changed in response to this notification. Therefore, the reason why the fuel dilution amount reset process is performed after the oil change is based on the fact that the dilution of the oil by fuel is eliminated by the oil change.

[0024] When the fuel dilution amount reset process is executed, the engine ECU 24 first inputs the intake air amount Qa and the fuel injection correction rate Fk (step S100). The intake air amount Qa can be input from the engine ECU 24 via communication after being detected by the airflow meter 123a. The fuel injection correction rate Fk can be input from the engine ECU 24 via communication after being determined from the correction value k in the air-fuel ratio feedback control.

[0025] Next, it is determined whether the intake air volume Qa is less than the threshold Qref (step S110). If it is determined that the intake air volume Qa is less than the threshold Qref, the threshold value F1 is set to the determination threshold Fref (step S120). If it is determined that the intake air volume Qa is greater than or equal to the threshold Qref, the threshold value F2, which is greater than the value F1, is set to the determination threshold Fref (step S130). In the region where the intake air volume Qa is less than the threshold Qref, the effect of dilution of oil by fuel becomes significant, so a value F1 smaller than the value F2 used as the determination threshold Fref in the region where the intake air volume Qa is greater than or equal to the threshold Qref is set to the determination threshold Fref.

[0026] Next, it is determined whether the fuel injection correction rate Fk is equal to or greater than the determination threshold Fref (step S140). This determination determines whether or not the dilution of oil by the fuel has been resolved. If it is determined that the fuel injection correction rate Fk is equal to or greater than the determination threshold Fref, it is determined that the dilution of oil by the fuel has been resolved, and the fuel dilution amount Fd is reset to 0 (step S150), and this process ends. On the other hand, if it is determined that the fuel injection correction rate Fk is less than the determination threshold Fref, it is determined that the dilution of oil by the fuel has not been resolved, and this process ends without resetting the fuel dilution amount Fd to 0.

[0027] Figure 4 is an explanatory diagram showing the relationship between intake air volume Qa, fuel injection correction rate Fk after oil change, and judgment threshold Fref. In the figure, the solid line represents the fuel injection correction rate Fk after an oil change when a good oil change is performed, and the dashed line represents the fuel injection correction rate Fk after an oil change when a poor oil change is performed. As shown in the figure, when a good oil change is performed, the fuel injection correction rate Fk after an oil change is greater than the judgment threshold Fref, and it is judged that the dilution of oil by fuel has been resolved, and the fuel dilution amount Fd is reset to a value of 0. If the judgment threshold Fref is set to a value of F2 regardless of the intake air volume Qa, even when a good oil change is performed, the fuel injection correction rate Fk will be less than the judgment threshold Fref(F2) in the region where the intake air volume Qa is less than the value Qref, and it will be incorrectly judged that the dilution of oil by fuel has not been resolved. As shown by the dashed line, when a faulty oil change is performed, the fuel injection correction rate Fk will be below the threshold Fref in the region where the intake air volume Qa is less than the value Qref, or in the region where the intake air volume Qa is greater than or equal to the value Qref, and it is determined that the dilution of the oil by fuel has not been resolved.

[0028] In the engine system installed in the hybrid vehicle 20 of the embodiment described above, when the intake air volume Qa is less than the threshold Qref, the determination threshold Fref is set to value F1, and when the intake air volume Qa is greater than or equal to the threshold Qref, the determination threshold Fref is set to value F2, which is greater than value F1. When the fuel injection correction rate Fk is greater than or equal to the determination threshold Fref, it is determined that the dilution of oil by fuel has been resolved, and the fuel dilution amount Fd is reset to value 0. When the fuel injection correction rate Fk is less than the determination threshold Fref, it is determined that the dilution of oil by fuel has not been resolved, and the fuel dilution amount Fd is not reset to value 0. By using a small value (F1) as the determination threshold Fref in the region where the intake air volume Qa is less than the threshold Qref, it is possible to suppress the misjudgment that the dilution of oil by fuel has not been resolved. In other words, it is possible to more appropriately confirm the resolution of fuel dilution after an oil change.

[0029] In the engine system installed in the hybrid vehicle 20 of the embodiment, when the intake air volume Qa is less than the threshold Qref, the determination threshold Fref is set to a value F1, and when the intake air volume Qa is equal to or greater than the threshold Qref, the determination threshold Fref is set to a value F2 that is greater than the value F1. However, as shown in the explanatory diagram of the modified example in Figure 5, which shows the relationship between the intake air volume Qa, the fuel injection correction rate Fk after oil change, and the determination threshold Fref, a small first predetermined value F1 may be set as the determination threshold Fref when the intake air volume Qa is less than the first predetermined air volume Q1, a second predetermined value F2 that is greater than the first predetermined air volume Q1 and less than the second predetermined air volume Q2 may be set as the determination threshold Fref, and a third predetermined value F3 that is greater than the second predetermined air volume Q2 may be set as the determination threshold Fref. Alternatively, the determination threshold Fref may be set to increase steplessly with respect to the magnitude of the intake air volume Qa.

[0030] In the engine system installed in the hybrid vehicle 20 of the embodiment, when the intake air volume Qa is less than the threshold Qref, the determination threshold Fref is set to value F1, and when the intake air volume Qa is equal to or greater than the threshold Qref, the determination threshold Fref is set to value F2, which is greater than value F1. However, since the learning region for the air-fuel ratio of the engine 22 is often divided into a low air volume learning region where the intake air volume is relatively small and a high air volume learning region where the intake air volume is relatively large, it is also possible to set the determination threshold Fref to value F1 in the low air volume learning region and to set the determination threshold Fref to value F2, which is greater than value F1, in the high air volume learning region.

[0031] In the hybrid vehicle 20 of this embodiment, the engine system is provided with an engine 22 having a port injection valve 126 for injecting fuel into the intake port and an in-cylinder injection valve 127 for injecting fuel into the cylinder. However, the system may also be provided with an engine having only an in-cylinder injection valve and no port injection valve, or an engine having only a port injection valve and no in-cylinder injection valve.

[0032] In this embodiment, the engine unit is designed to be 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.

[0033] 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, engine 22 corresponds to "engine," and engine ECU 24 corresponds to "control device."

[0034] Furthermore, the correspondence between the main elements of the examples and the main elements of the invention described in the section on means for solving the problem is not intended to limit the elements of the invention described in the section on means for solving the problem, as the examples are merely one example to specifically illustrate a form for carrying out the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the examples are merely one specific example of the invention described in the section on means for solving the problem.

[0035] Although embodiments for carrying out the present invention have been described above using examples, the present invention is not limited in any way to these embodiments, and can be carried out in various forms without departing from the spirit of the present invention. [Industrial applicability]

[0036] This invention can be used in industries such as the manufacturing of engine equipment. [Explanation of Symbols]

[0037] 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

1. An engine system comprising an engine and a control device for controlling the engine, When a reset request is made based on an oil change for the estimated oil dilution value by fuel, the control device sets a determination threshold that tends to increase as the intake air volume increases, and determines whether the dilution of oil by fuel has been resolved based on whether the fuel injection correction value in the air-fuel ratio feedback control is equal to or greater than the determination threshold. If it is determined that the dilution has been resolved, the control device resets the estimated oil dilution value. An engine device characterized by the following features.

2. The engine device according to claim 1, The threshold for determination increases in one or two steps within a range where the intake air volume is relatively small. Engine equipment.

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