Control device for vehicle with internal combustion engine

Abstract

To effectively suppress or reduce dilution of oil by fuel.SOLUTION: A control device 16 for a vehicle with an internal combustion engine controls the vehicle mounted with the internal combustion engine lubricated by oil that is diluted by inclusion of fuel as a driving source. The control device includes: a traveling estimation section 16A that determines a traveling schedule of the vehicle; a dilution amount estimation section 16B that determines a dilution amount of oil by fuel when the vehicle travels in accordance with the traveling schedule determined by the traveling estimation section 16A; and a control selection section 16C that performs selection of dilution reduction control including execution and prohibition of the dilution reduction control for reducing the dilution amount on the basis of the dilution amount determined by the dilution amount estimation section 16B.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a device for controlling a vehicle equipped with an internal combustion engine as a driving force source of the vehicle, and more particularly to a device for performing control to reduce or suppress dilution of oil by fuel. [Background technology]

[0002] In internal combustion engines such as gasoline engines, which output power by burning a pressurized and compressed mixture of air and fuel inside a cylinder, it is known that the fuel can mix with the engine oil and dilute the engine oil, or that an increased amount of dilution can cause problems. Various technologies have been proposed to avoid or suppress engine oil dilution or to reduce the amount of dilution.

[0003] As an example, Patent Document 1 describes a control device for a hybrid vehicle equipped with both an internal combustion engine and an electric motor as a driving force source, which aims to suppress oil dilution by fuel during warm-up of the internal combustion engine and simultaneously complete warm-up early. The control device is configured to reduce the load on the internal combustion engine to suppress oil dilution if the temperature of the internal combustion engine is low when the amount of dilution is high, such as during warm-up, and to increase the load on the internal combustion engine to promote warm-up if the temperature of the internal combustion engine is high. Furthermore, the control device described in Patent Document 1 compensates for a decrease in driving force due to a decrease in the load on the internal combustion engine by increasing the output of the electric motor, and also compensates for a decrease in energy efficiency by converting a portion of the increased output due to an increase in the load on the internal combustion engine into electricity and charging it. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-94992 Summary of the Invention [Problem to be solved by the invention]

[0005] The control device described in Patent Document 1 increases or decreases the engine load and simultaneously controls charging and discharging based on the estimated current dilution amount. Therefore, when the engine temperature is low, the engine load is reduced, i.e., the intake air volume and fuel injection volume are reduced, thereby suppressing the amount of fuel that mixes with the oil without being burned, i.e., the dilution amount. Furthermore, when the engine temperature is high, fuel is less likely to evaporate and dilute the oil, so the engine load is increased to promote warm-up. However, because engine or oil temperature changes depending on the vehicle's running or driving conditions, the control device described in Patent Document 1 may unnecessarily increase or decrease the engine load or perform charging and discharging, resulting in poor fuel economy or electricity consumption. Conversely, the frequency of such control may increase, resulting in a transient increase in the dilution amount. For example, if the dilution amount is high initially while the vehicle is running continuously at a certain load, the engine temperature or engine oil temperature is likely to rise during subsequent driving, reducing the dilution amount. However, the control device described in Patent Document 1 operates the engine to promote warm-up based on the estimated current dilution amount and temperature, which may result in unnecessary engine operation and poor fuel economy. Furthermore, if the engine temperature is low and the engine load is reduced while driving, and the driving environment forces the vehicle to drive at a slower speed, or the driving environment requires repeated stops and therefore the engine temperature does not rise, the amount of oil dilution cannot be improved, or the amount of dilution may increase over time.

[0006] The present invention has been made with an eye on the above-mentioned technical problems, and aims to provide a vehicle control device that can effectively suppress or reduce dilution of oil that lubricates an internal combustion engine by fuel. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a control device for a vehicle equipped with an internal combustion engine, which controls a vehicle equipped with an internal combustion engine as a driving force source, the internal combustion engine being lubricated by oil diluted by the mixing of fuel, and is characterized by comprising: a driving estimation unit which determines a driving schedule for the vehicle; a dilution amount estimation unit which determines the amount of dilution of the oil with the fuel when the vehicle drives in accordance with the driving schedule determined by the driving estimation unit; and a control selection unit which selects the dilution reduction control, including the execution and prohibition of dilution reduction control that reduces the dilution amount, based on the dilution amount determined by the dilution amount estimation unit. [Effects of the Invention]

[0008] In the present invention, the driving schedule from the current point in time onward and the dilution amount when driving according to the driving schedule are estimated, and dilution reduction control is selected based on the estimation. For example, if it is estimated that the internal combustion engine will be driven at a low load, the system drives the vehicle in a different manner from the estimated driving mode, i.e., increases the load on the internal combustion engine, or increases mechanical or cooling losses, thereby promoting an increase in the temperature of the internal combustion engine. Alternatively, the oil is heated using a heater or the like to increase its temperature. As a result, an increase in the oil dilution amount can be effectively avoided or suppressed. Conversely, even if the dilution amount is currently high, if driving is planned that places a high load on the internal combustion engine, such as uphill, the temperature of the internal combustion engine will increase as the vehicle travels, reducing the dilution amount. Therefore, dilution reduction control is prohibited or a low level of dilution reduction control is selected. As a result, the energy consumed by dilution reduction control can be reduced or eliminated, thereby improving fuel economy or energy efficiency. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a list of components of a vehicle to which the present invention is applied. [Figure 2] FIG. 2 is a block diagram showing the functional configuration of the control device. [Figure 3] 3 is a flowchart illustrating an example of control executed by the control device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the embodiment described below is merely an example of how the present invention can be implemented, and is not intended to limit the present invention.

[0011] A vehicle 1 in an embodiment of the present invention is a vehicle equipped with an internal combustion engine 2 as a driving force source, and examples thereof include a so-called engine vehicle that uses only the internal combustion engine 2 as a driving force source, and a hybrid vehicle (HV, PHV) that uses a motor (or motor-generator: MG) as a driving force source in addition to the internal combustion engine 2. The example shown in Fig. 1 is an example of a hybrid vehicle equipped with an internal combustion engine (hereinafter referred to as engine) 2 and a motor (MG) 3.

[0012] The engine 2 and motor 3 may have the same configuration as conventionally known engines and motors. Therefore, the engine 2 mainly has the components listed in FIG. 1 . It has a cylinder and piston 4 for burning a mixture of fuel and air and generating power. It is provided with an injector 5 for supplying the fuel. The injector 5 may be configured to inject fuel into the intake port of the cylinder, or may be configured to inject fuel into the combustion chamber (inside the cylinder), or may have both. The injector 5 can not only appropriately control the amount of fuel injected (supplied), but also adjust the injection timing.

[0013] An ignition plug (spark plug) 6 is provided to combust the air-fuel mixture in the combustion chamber. The timing of this ignition can be controlled as needed. Intake valves and exhaust valves 7 are provided to take in and exhaust air from the combustion chamber. The opening and opening / closing timing of these valves 7 can be controlled as needed. An electronic throttle valve 8 is provided to control the amount of air taken in. The electronic throttle valve 8 is configured to change its opening depending on the amount of depression of the accelerator pedal (not shown), and also adjusts its opening for warming up and idling.

[0014] An oil pan / oil pump 9 is provided to store oil for lubricating moving parts such as pistons and to supply oil to necessary locations. An oil temperature sensor 10 detects the oil temperature, and an oil heater 11 appropriately heats the oil in the oil pan. Fuel inevitably mixes with the oil, diluting it. As the oil temperature rises, the fuel evaporates, resulting in unburned gas or a mixture leaking into the crankcase, causing blow-by gas to accumulate in the crankcase. A PCV (Positive Crankcase Ventilation) 12 is provided to recirculate the blow-by gas to the intake side for combustion. A radiator 13 is also provided to cool the cylinder block, oil, and other components. The radiator 13 is configured to cool the coolant by dissipating heat from the air, for example, by driving a motor to rotate a fan depending on the coolant temperature.

[0015] The vehicle 1 is equipped with a controller 14 that controls the amount and timing of fuel injection by the injector 5, the opening and opening / closing timing of the intake valve and exhaust valve 7, the opening of the electronic throttle valve 8, the on / off of the oil heater 11, the on / off of cooling by the radiator 13, and the drive of the motor 3. The controller 14 is an electronic control device that mainly uses a computer comprising an arithmetic element (CPU), memory elements (RAM, ROM), and various interfaces, and is configured to perform calculations according to a predetermined program using input data and pre-stored data, and to output the results of the calculations as control signals.

[0016] In the embodiment described herein, the controller 14 is configured to primarily perform control to reduce or suppress the amount of oil dilution by fuel based on the vehicle 1's travel schedule. Therefore, data input from various sensors includes the oil temperature detected by the oil temperature sensor 10, the engine 2 operating time, the fuel injection amount or injection time, and the engine 2 coolant temperature, as well as road information for the planned travel route. A navigation system (NAVI) 15 is installed in the vehicle 1 to obtain this route and road information. The NAVI 15 may have a conventionally known configuration and detects the vehicle's position on map data and outputs road information such as the type and gradient of the road on which the vehicle is traveling. If a destination is entered on the map data, the NAVI 15 determines and outputs the travel route to the destination and the road information. Furthermore, the destination may be, for example, the nearest interchange ahead in the direction of travel if the vehicle is on a highway, or it may be a location that the vehicle has reached several times in the past if the vehicle has traveled along a road frequently.

[0017] The control device 16 in the embodiment described here is composed of the above-mentioned controller 14 and NAVI 15, or is an electronic control device that integrates these controller 14 and NAVI 15, and has a configuration that performs the functions shown in Figure 2 as a configuration for controlling the amount of oil dilution based on the driving schedule of the vehicle 1.

[0018] The travel estimation unit 16A calculates a travel schedule for the vehicle 1. The travel schedule is essentially a travel route from the current location to a destination, and the destination is, as described above, a point input to the NAVI 15 or a point determined from the road conditions of the travel route or past travel records. These points can be calculated by the NAVI 15.

[0019] When the vehicle 1 travels, the amount of oil dilution varies depending on the driving conditions of the engine 2 during the travel. The control device 16 is provided with a dilution amount estimation unit 16B that estimates the amount of oil dilution that would occur if the vehicle 1 traveled as estimated by the travel estimation unit 16A. Because the amount of oil dilution varies depending on the load on the engine 2, the duration of operation, or the duration of a rest period, the operating conditions of the engine 2 along the planned travel route are estimated based on road information for the travel route, and the dilution amount is estimated based on the estimated operating conditions. Here, the "estimated operating conditions" refer to basic operating conditions required of the vehicle 1, such as fuel economy, power consumption, and exhaust gas purification, and may be operating conditions pre-prepared for engine 2 control. Road information is acquired by the navigation system 15, and includes information such as urban roads, expressways, paved roads, muddy roads, uphill / downhill roads, altitude, temperature, the presence or absence of traffic jams, and the distances involved. The operating conditions of the engine 2 are estimated from such road information, and the amount of oil dilution is estimated based on the operating conditions. For example, in urban roads where vehicle speed is limited, frequent stops at traffic lights (intermittent engine operation), or extended downhill roads result in extended engine 2 stop times, engine temperature does not rise easily, and dilution does not progress, but the dilution amount does not decrease. Conversely, in cases where steady-state driving at high speeds continues or heavy uphill roads continue, engine temperature rises quickly, causing fuel evaporation from the oil to progress and reducing the dilution amount. Note that the oil dilution amount also increases or decreases depending on factors such as lean or rich operation of engine 2, outside temperature, and the degree of cooling by radiator 13. Therefore, the operation of engine 2 or the driving of vehicle 1 may be simulated in advance based on road information, and the results may be prepared and stored in advance in the form of a map, and the dilution amount may be estimated from the map.

[0020] The control device 16 is provided with a control selection unit 16C that selects whether to execute or prohibit control to reduce the dilution amount and the content of that control based on the estimated dilution amount. Control to reduce the oil dilution amount mainly involves control to prevent or suppress fuel mixing into the oil and control to evaporate fuel from the oil. Examples of control to prevent or suppress fuel mixing into the oil include control to reduce the fuel injection amount (or engine load) and control to prohibit direct injection or reduce the proportion of direct injection. Control to evaporate fuel from the oil essentially involves control to increase the engine temperature or oil temperature, and examples of such control include control to increase the charge level of a battery (not shown) connected to the motor 3, control to heat the oil using the oil heater 11, control to prohibit or limit intermittent operation of the engine 2, and control to increase mechanical loss or cooling loss in the drive system including the engine 2 and motor 3.

[0021] An example of control by the control device 16 will be described with reference to the flowchart shown in FIG. 3. Note that the step numbers in FIG. 3 are assigned to identify the control and do not specify the order of control. The routine shown in FIG. 3 is executed when the vehicle 1 is running, and first, the oil temperature is obtained (step S1). The oil temperature can be detected directly by the oil temperature sensor 10, or alternatively, it may be obtained based on the engine water temperature. In addition, the current estimated dilution amount is obtained (step S2). The relationship between the oil temperature and the dilution amount may be obtained by estimating the dilution amount based on this relationship and the oil temperature, or the dilution amount estimated from past driving or running conditions may be stored and the estimated dilution amount may be obtained.

[0022] Furthermore, a destination point for the planned travel is acquired (step S3). This destination point and its acquisition are as described above, and can be executed by the travel estimation unit 16A. The amount of oil dilution after the travel is estimated based on the predicted operation of the engine (internal combustion engine) 1 if the vehicle is to travel to the destination point (step S4). The control of this step S4 can be executed by the dilution amount estimation unit 16B, and the details of this control are as described for the dilution amount estimation unit 16B.

[0023] Based on the estimated dilution amount after driving, it is determined whether or not to reduce the dilution amount (step S5). For example, a threshold value for determining the dilution amount after driving is prepared in advance, and if the estimated dilution amount exceeds the threshold value, a "yes" determination is made in step S5, and otherwise a "no" determination is made. Therefore, even if the current dilution amount is low, if the dilution amount would exceed the threshold value if the vehicle were subsequently driven under the basic driving conditions described above. Conversely, even if the current dilution amount is high, if the dilution amount would not exceed the threshold value if the vehicle were subsequently driven under the basic driving conditions described above, control aimed at reducing the dilution amount is not performed.

[0024] Therefore, if the result of the determination in step S5 is "Yes," the control is changed to a control for reducing the dilution amount to a predetermined target amount (dilution reduction control) (step S6). The control changed and selected in step S6 is the control mentioned in the description of the control selection unit 16C above, and the control contents such as the control of the engine 2, the control of the motor 3, the control of the radiator 13, and the control of the oil heater 11 are changed so as to increase the oil temperature and evaporate the fuel from the oil.

[0025] Next, the estimated dilution amount is updated (step S7), and the routine shown in Figure 3 is temporarily terminated. If the control is changed in step S6 above, the dilution amount after the changed control is executed is updated as the estimated dilution amount. Also, if the result of the determination in step S5 above is "NO," the process immediately proceeds to step S7, and the dilution amount at that time is updated as the estimated dilution amount.

[0026] Therefore, according to the control device of the embodiment of the present invention, even if the current amount of oil dilution is small, if it is estimated that the dilution amount will increase with subsequent driving, the control state or operating state of the engine 2 and the like for subsequent driving will be changed, thereby preventing or suppressing an increase in the amount of oil dilution. Conversely, even if the current amount of oil dilution is large, if it is estimated that the dilution amount will decrease or not increase with subsequent driving, control to intentionally reduce the amount of dilution will not be executed, thereby preventing or suppressing energy consumption beyond that required for driving under so-called basic driving conditions, and preventing a deterioration in energy efficiency or fuel economy.

[0027] The present invention is not limited to the above-described embodiment, and the vehicle may be a so-called engine vehicle other than a hybrid vehicle as long as it has an internal combustion engine as a power source. In this case, control to change the charge / discharge rate of the battery is not performed to increase the engine temperature or oil temperature. Furthermore, road information for the planned driving route may be obtained through VICS or vehicle-to-vehicle communication. [Explanation of symbols]

[0028] 1 vehicle 2. Internal combustion engine 3 motors 4 Cylinders and Pistons 5 injectors 6 Spark plugs 7 Intake valves and exhaust valves 8. Electronic Throttle Valve 9 Oil pan and oil pump 10 Oil temperature sensor 11 Oil heater 12 PCV(Positive Crankcase Ventilation) 13 Radiator 14 Controller 15 NAVI 16 Control device 16A Travel estimation unit 16B Dilution amount estimation section 16C Control selection section

Claims

[Claim 1] A control device for a vehicle equipped with an internal combustion engine, which controls a vehicle equipped with an internal combustion engine as a driving force source, the internal combustion engine being lubricated by oil diluted by the mixture of fuel, a travel estimation unit that calculates a travel schedule for the vehicle; a dilution amount estimation unit that calculates the amount of dilution of the oil with the fuel when the vehicle runs according to the running schedule calculated by the running estimation unit; a control selection unit that selects a dilution reduction control, including execution or prohibition of a dilution reduction control for reducing the dilution amount, based on the dilution amount calculated by the dilution amount estimation unit; A control device for a vehicle equipped with an internal combustion engine, comprising:

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