Plug-in hybrid vehicle control device

Abstract

A controller for a plug-in hybrid vehicle implemented with an engine maintenance mode for forcibly running an engine to facilitate loading of new fuel, the controller comprising: a deteriorated fuel calculation unit that calculates an amount of deteriorated fuel from an amount of loading and an amount of usage of fuel upon the lapse of a predetermined deterioration period after fueling, and a deteriorated fuel determination unit that determines whether the amount of deteriorated fuel calculated by the deteriorated fuel calculation unit is equal to or larger than a predetermined deterioration determination threshold value. If the determination result in the deteriorated fuel determination unit is equal to or larger than the deterioration determination threshold value, the engine maintenance mode is started or the started engine maintenance mode is continued. If the determination result is smaller than the deterioration determination threshold value, the engine maintenance mode is not started or the started engine maintenance mode is cancelled.

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a plug-in hybrid vehicle. [Background technology]

[0002] 2. Description of the Related Art Among electrically powered vehicles, there are known plug-in hybrid vehicles in which the battery can be externally charged from outside the vehicle and also external power can be supplied to the outside of the vehicle.

[0003] Some plug-in hybrid vehicles are designed to switch between an EV mode, in which the drive wheels are driven solely by the motor, a series mode, in which the motor is used as the power source and the engine is also used as a power source (generator), or a parallel mode, in which both the engine and the motor are used as power sources, depending on the driving conditions, which can significantly reduce fuel consumption.

[0004] However, fuel used in engines gradually deteriorates if it is left in the fuel tank or piping for a long time. For example, the volatile components of the fuel may evaporate, causing the ratio of fuel components to become inappropriate. This fuel deterioration may lead to engine malfunction or breakdown.

[0005] Plug-in hybrid vehicles can run on electric power for long periods of time by externally charging the battery from outside the vehicle. Depending on how the user uses the vehicle, they may be used in EV mode, i.e., as an electric vehicle, which can easily lead to the aforementioned situation and can cause engine malfunctions or breakdowns due to the engine being left unused for long periods of time.

[0006] To address such problems caused by leaving the engine of a plug-in hybrid vehicle unused for a long period of time, for example, Patent Document 1 discloses that if the engine has not been operated (= fuel consumption = opportunity to refuel) within a predetermined period of time, an "engine maintenance mode" is implemented to forcibly operate the engine. Furthermore, it discloses that the amount of fuel consumed in the engine maintenance mode is displayed to the driver. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6368938 Summary of the Invention [Problem to be solved by the invention]

[0008] In plug-in hybrid vehicles, the condition for starting engine maintenance mode is generally a predetermined amount of new fuel required to prevent fuel degradation within a specified period of time, and if that amount of new fuel is not supplied within the specified period, engine maintenance mode will start, or once started, engine maintenance mode often cannot be canceled unless that amount of new fuel is supplied.

[0009] However, some users may refuel multiple times within a specified period with small amounts of new fuel that do not reach the required amount. In such cases, the required amount of new fuel is not supplied at once, which can cause problems such as the start of a maintenance mode or the inability to cancel an activated engine maintenance mode. This makes it cumbersome for drivers to manage the supply of more than the required amount of new fuel at once.

[0010] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a control device that can prevent the engine maintenance mode for a plug-in hybrid vehicle, which is designed to prevent fuel deterioration due to the engine being left unused for a long period of time, from starting even if a predetermined amount or more of new fuel is not refueled at one time within a predetermined period of time. [Means for solving the problem]

[0011] (1) In order to achieve the above object, at least one embodiment of a control device for a plug-in hybrid vehicle according to the present disclosure is a control device for a plug-in hybrid vehicle that includes a drive motor that operates with power supplied from a battery and provides driving force to the vehicle, and an engine that operates with fuel supplied from a fuel tank and provides driving force to the vehicle or a generator, and that implements an engine maintenance mode that forcibly operates the engine to prompt the refueling of new fuel in order to prevent fuel deterioration resulting from the engine being left unused for a long period of time. The control device includes a degraded fuel calculation unit that calculates the amount of degraded fuel that has passed a predetermined deterioration period or more since refueling based on the amount of fuel supplied and the amount of fuel used, and a degraded fuel determination unit that determines whether the amount of degraded fuel calculated by the degraded fuel calculation unit is equal to or greater than a predetermined deterioration determination threshold. If the determination result of the degraded fuel determination unit is equal to or greater than the deterioration determination threshold, the control device starts the engine maintenance mode or continues it if it has started, and if it is less than the deterioration determination threshold, the control device does not start the engine maintenance mode or cancels it if it has started. The deteriorated fuel calculation unit manages the amount of fuel refueled and the amount of fuel used since the previous refueling at each time of refueling, and the deteriorated fuel calculation unit has an update unit that updates the amount of remaining fuel since the previous refueling calculated at each time of refueling to calculate the amount of remaining fuel at the time of current refueling, and the update unit calculates the amount of deteriorated fuel, which is the amount of remaining fuel that has elapsed since the previous refueling for a deterioration period or more, and updates the amount of remaining fuel by the update unit by subtracting "the amount of fuel used from the previous refueling to the current refueling" from "the amount of remaining fuel since the previous refueling calculated at the time of previous refueling." do.

[0012] According to this configuration (1), the degraded fuel calculation unit calculates the amount of degraded fuel that has been degraded for a predetermined period of time since refueling, and the operation of the engine maintenance mode is controlled based on the calculated amount of degraded fuel.

[0013] That is, when the degraded fuel determination unit determines that the amount of degraded fuel is equal to or greater than the degradation determination threshold, the engine maintenance mode is started or, if started, is continued, thereby suppressing the adverse effects of degraded fuel on the engine.

[0014] Furthermore, if it is determined that the amount of degraded fuel is less than the degradation determination threshold, the engine maintenance mode is not activated, or if activated, is canceled. Since even a small amount of fuel can be replaced with new fuel without the need to refuel a large amount at once, there are cases where the engine maintenance mode does not need to be activated as the amount of degraded fuel decreases. This reduces the burden on the driver of managing the amount of fuel refueled. Furthermore, the update unit updates the remaining fuel amount since the previous refueling calculated at the previous refueling time and calculates the remaining fuel amount since the previous refueling time at the current refueling time, so that the amount of deteriorated fuel, which is the remaining fuel amount for which more than the deterioration period has passed since the previous refueling, can be calculated with high accuracy. Furthermore, the update unit updates and calculates the remaining fuel amount since the previous refueling time at each refueling time, so that the remaining fuel amount since the previous refueling time can be calculated accurately.

[0015] (2) In some embodiments, in configuration (1), the degraded fuel calculation unit manages the amount of fuel supplied and the amount of fuel used for each unit period, with a predetermined fixed period being a unit period, and the degraded fuel calculation unit has an update unit that updates the amount of remaining fuel from the time of refueling calculated in the previous unit period for each unit period to calculate the amount of remaining fuel for the current unit period, and the update unit calculates the amount of degraded fuel, which is the amount of remaining fuel that has passed since the time of refueling for more than a degradation period.

[0016] According to this configuration (2), a predetermined fixed period is set as a unit period, and the update unit updates the remaining fuel amount since refueling calculated in the previous unit period for each unit period to calculate the remaining fuel amount since refueling in the current unit period, so that the deteriorated fuel amount, which is the remaining fuel amount that has elapsed since refueling for more than the deterioration period, can be accurately calculated.

[0017] (3) In some embodiments, in the configuration (2), the update unit updates the remaining fuel amount by subtracting the “amount of fuel used in the current unit period” from the “amount of remaining fuel since refueling calculated in the previous unit period.”

[0018] According to this configuration (3), the remaining fuel amount since refueling is updated and calculated for each unit period by the update unit, so that the remaining fuel amount since refueling can be accurately calculated.

[0023] ( 4 In some embodiments, the configurations (1) to ( 3In any one of the configurations above, the control device includes an engine maintenance mode prediction unit that predicts when an engine maintenance mode will be initiated based on the amount of degraded fuel calculated by the degraded fuel calculation unit.

[0024] Such a configuration ( 4 According to the above, the engine maintenance mode prediction unit can predict the timing at which the engine maintenance mode will be initiated based on the amount of degraded fuel calculated by the degraded fuel calculation unit.

[0025] ( 5 ) In some embodiments, the configuration ( 4 ) and further comprising a display control unit that controls a display unit that notifies the driver of the start time predicted by the engine maintenance mode prediction unit.

[0026] Such a configuration ( 5 According to the above, the display control unit can notify the driver of the timing to start the engine maintenance mode, and can encourage the driver to refuel. [Effects of the Invention]

[0027] According to at least one embodiment of the control device for a plug-in hybrid vehicle of the present disclosure, an engine maintenance mode for preventing fuel deterioration due to the engine being left unused for a long period of time can be set so that the engine will not start even if a predetermined amount or more of new fuel is not refueled at one time within a predetermined deterioration period. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a configuration block diagram that schematically illustrates the overall configuration of a plug-in hybrid vehicle and a control device according to an embodiment of the present disclosure. [Figure 2] 4 is a flowchart showing a control flow in the control device. [Figure 3] 3 is a flowchart of a subroutine for calculating the amount of degraded fuel in the flowchart of FIG. 2. [Figure 4]10 is a table showing an example of calculation of the amount of degraded fuel in the degraded fuel calculation unit; [Figure 5] 10 is a flowchart showing a control flow of a control device according to another embodiment. [Figure 6] 7 is a flowchart of a subroutine for calculating the amount of degraded fuel in the flowchart of FIG. 6. [Figure 7] FIG. 2 is a schematic diagram of a display screen displayed on a display unit. [Figure 8] FIG. 2 is a schematic diagram of a display screen displayed on a display unit. DETAILED DESCRIPTION OF THE INVENTION

[0029] A control device for a plug-in hybrid vehicle according to an embodiment of the present disclosure will be described below with reference to the drawings. The embodiment shows one aspect of the present disclosure, and is not intended to be limiting and may be modified as desired within the scope of the technical concept of the present disclosure.

[0030] 1 to 4, 7, and 8. As shown in the overall configuration diagram of Fig. 1, a plug-in hybrid vehicle (PHV, PHEV) 1 is a vehicle equipped with an engine 3 and a rotary electric motor (drive motor 5) having a motor function, and is capable of being charged from a power source external to the vehicle and supplying electric power to an external device.

[0031] Furthermore, the plug-in hybrid vehicle (hereinafter referred to as the vehicle) 1 is equipped with a generator 7 driven by the engine 3, a drive battery 9 that supplies power to the drive motor 5 and is supplied with power generated by the generator 7, wheels 11 that are driven by the driving force generated by the engine 3 or the drive motor 5, and a transaxle 13 that transmits the driving force generated by the engine 3 or the drive motor 5 to the wheels 11.

[0032] Furthermore, the vehicle 1 includes a fuel tank 15 that stores fuel to be supplied to the engine 3, a motor control unit 17 that controls the drive motor 5 and the generator 7, and an engine control unit 19 that controls the engine 3. Although the drive system in Fig. 1 shows a four-wheel drive vehicle, it may also be a two-wheel drive vehicle.

[0033] Furthermore, the vehicle 1 is equipped with an engine operation pattern called an "engine maintenance mode" that periodically forcibly operates the engine 3 to prompt the supply of new fuel in order to prevent fuel deterioration resulting from leaving the engine 3 unused for a long period of time. The vehicle 1 is also equipped with a control device 21 that controls the start and end of operation in this engine maintenance mode. The control device 21 instructs the engine control unit 19 to start and end the engine maintenance mode, and the engine control unit 19 controls the operation of the engine 3 according to the vehicle state.

[0034] On the other hand, in plug-in hybrid vehicles, the condition for starting the engine maintenance mode is generally determined by the automobile manufacturer in advance as a condition for refueling the engine, which is to prevent fuel from deteriorating within a predetermined period (deterioration period) from the time of refueling. If the new fuel amount is not refueled within the predetermined period, the engine maintenance mode is started, or once started, the engine maintenance mode cannot be canceled unless the new fuel amount is refueled.

[0035] The problem of fuel degradation due to engines being left unused for long periods of time is caused by an increase in the amount of degraded fuel. Therefore, it is considered appropriate to focus on the amount of degraded fuel rather than on whether or not new fuel is being added, as in the past, and to control the start and end of engine maintenance mode depending on whether the amount of degraded fuel is above or below a standard value.

[0036] Based on the above-mentioned idea, in this embodiment, the control device 21 is equipped with a degraded fuel calculation unit 23 that calculates the amount of degraded fuel (degraded fuel amount) that has passed a predetermined degradation period or more since the last time of refueling from the amount of fuel supplied and the amount of fuel used, as shown in Figure 1, and a degraded fuel determination unit 25 that determines whether the degraded fuel amount calculated by the degraded fuel calculation unit 23 is equal to or greater than a predetermined degradation determination threshold.

[0037] If the judgment result of the deteriorated fuel judgment unit 25 is equal to or greater than the deterioration judgment threshold, the engine maintenance mode is started or, if started, is continued, and if the judgment result is less than the deterioration judgment threshold, the engine maintenance mode is not started or, if started, is canceled.

[0038] In this embodiment, the deterioration period is defined as a predetermined period of time that has elapsed since refueling, during which fuel deterioration that could lead to engine malfunction or failure due to long-term neglect of the engine is likely to occur. Fuel that has been in the deterioration period or longer is defined as degraded fuel, and the amount of degraded fuel is defined as the degraded fuel amount. Note that this degraded fuel amount also includes a degraded fuel amount rate, which is the ratio of the amount of degraded fuel to the amount of degraded fuel in a full fuel tank 15. Furthermore, the amount of degraded fuel that could lead to engine malfunction or failure is defined as the deterioration determination threshold. Therefore, the deterioration period and the deterioration determination threshold differ depending on the capacity of the fuel tank 15, and are therefore values that are appropriately set by testing, calculation, or the like.

[0039] According to the configuration of the above embodiment, the degraded fuel calculation unit 23 calculates the amount of degraded fuel that has been degraded for more than the degradation period since the last time of refueling from the amount of fuel supplied and the amount of fuel used, and the operation of the engine maintenance mode can be controlled based on the calculated amount of degraded fuel.

[0040] That is, when the degraded fuel determination unit 25 determines that the amount of degraded fuel is equal to or greater than the degradation determination threshold, the engine maintenance mode is started, or if started, is continued. This makes it possible to suppress adverse effects of degraded fuel on the engine 3.

[0041] Furthermore, if the degraded fuel determination unit 25 determines that the amount of degraded fuel is less than the degradation determination threshold, the engine maintenance mode is not activated, or if activated, is canceled. This is because even a small amount of fuel can be replaced with new fuel without having to refuel a large amount at once, reducing the amount of degraded fuel and eliminating the need to activate the engine maintenance mode. This reduces the burden on the driver of managing the amount of fuel refueled.

[0042] Therefore, the engine maintenance mode for preventing fuel deterioration due to long-term neglect of the engine 3 of the vehicle 1 can be prevented from starting even if a predetermined amount or more of new fuel is not supplied at one time within the deterioration period, and can be canceled if the engine has started even if a predetermined amount or more of new fuel is not supplied at one time.

[0043] In some embodiments, as shown in Figures 2 to 4, the degraded fuel calculation unit 23 of the control device 21 manages the amount of fuel supplied and the amount of fuel used for each unit period, with a predetermined fixed period being the unit period, and the degraded fuel calculation unit 23 has an update unit 27 that updates the amount of fuel remaining from the time of refueling calculated in the previous unit period for each unit period to calculate the amount of fuel remaining from the time of refueling in the current unit period, and the update unit 27 calculates the amount of degraded fuel, which is the amount of fuel remaining that has elapsed since the time of refueling for more than the degradation period.

[0044] Furthermore, the updating unit 27 updates the remaining fuel amount by subtracting the "amount of fuel used in the current unit period" from the "amount of fuel remaining since refueling calculated in the previous unit period." Note that the "amount of fuel remaining since refueling calculated in the previous unit period" and the "amount of fuel used in the current unit period" are calculated using the amount of fuel remaining at each refueling and the amount of fuel used at each refueling, respectively. In other words, the amount of fuel used is calculated and used by multiplying the amount of fuel used in the current unit period by the ratio of the amount of fuel remaining at each refueling since refueling calculated in the previous unit period (see a calculation example described later).

[0045] The control flow of the control device 21 will be described with reference to the control flowchart of Fig. 2. First, in step S1, it is determined whether refueling has occurred within a unit period. If yes, the process proceeds to step S2, where the amount of fuel refueled within the current unit period is acquired.

[0046] The amount of fuel supplied is obtained, for example, from the position of a float (float ball) installed in the fuel tank 15. The time of fuel supply is determined from a fuel cap removal signal or the like, and the amount of fuel supplied is obtained from the change in the position of the float at that time. If fuel is supplied multiple times within a unit time, the total amount of fuel supplied is used as the amount of fuel supplied for that unit period. Also, if it is determined in step S1 that no fuel has been supplied within the unit period, the result is No, and the amount of fuel supplied is zero (zero) in step S3.

[0047] In the next step S4, the amount of fuel used within the current unit period is obtained. For example, this is obtained by subtracting the amount of fuel supplied from the change in the amount of fuel in fuel tank 15 within the unit period. Alternatively, the amount of fuel actually supplied to the engine within the unit period may be obtained from engine control unit 19.

[0048] In the next step S5, the amount of degraded fuel that has been present for more than the degradation period since refueling is calculated. This degraded fuel amount is calculated according to the flow of the control flowchart of the subroutine shown in Figure 3. In Figure 3, first, in step S11, the amount of remaining fuel from the time of refueling for each previous unit period is obtained. In the next step S12, the amount of fuel used within the current unit period obtained in step S4 is obtained.

[0049] In the next step S13, the amount of fuel used obtained in step S12 is subtracted from the amount of remaining fuel obtained in step S11 to update the amount of remaining fuel since the time of refueling for each refueling calculated in the previous unit period, and the amount of remaining fuel since the time of refueling for each refueling for the current unit period is calculated.

[0050] In the next step S14, steps S11 to S13 are repeated for the deterioration period or more to calculate the deteriorated fuel amount, which is the remaining fuel amount after the deterioration period or more has elapsed.

[0051] Returning to the flowchart of Fig. 2, in step S6, it is determined whether the amount of degraded fuel calculated in step S5 is equal to or greater than the degradation determination threshold. If the determination result is No, the process returns to step S1 and repeats from S1. If the determination result in step S6 is Yes, the process proceeds to step S7, where an instruction is given to the engine control unit 19 to start the engine maintenance mode.

[0052] After the engine maintenance mode is started, in step S8, it is determined whether the amount of degraded fuel is less than the degradation determination threshold. If the determination result is No, the process returns to step S7 and the operation of the engine maintenance mode continues. If the determination result in step S8 is Yes, the process proceeds to step S9, where an instruction is issued to the engine control unit 19 to cancel the engine maintenance mode.

[0053] In addition, when determining whether the amount of degraded fuel is above or below the degradation judgment threshold, in order to ensure stability in operation when starting and canceling the engine maintenance mode, the degradation judgment threshold at start-up and the degradation judgment threshold at cancel may be set to different values, and the degradation judgment threshold at cancel may be set to a value smaller than the degradation judgment threshold at start-up.

[0054] In the above control flow, an example of calculation of the degraded fuel amount in step S5 will be described with reference to the table in Fig. 4. This calculation example is for a unit period of one month.

[0055] In the table in Figure 4, the vertical columns are the number of months elapsed, the unit period number, the total amount (fuel tank capacity), the amount of fuel used U (amount used since the previous time), the amount of remaining fuel S (total amount of fuel remaining in the fuel tank (X0+X1+X2+X3)), the amount of fuel refueled this time X0, the amount of fuel remaining one month later X1, the amount of fuel remaining two months later X2, and the amount of fuel remaining three months or more later X3, and the amount of fuel remaining for each of these items is shown in units of L (liters).

[0056] The one-month-old remaining fuel amount X1, the two-month-old remaining fuel amount X2, and the three-month-old remaining fuel amount X3 are calculated according to the following formulas (1), (2), and (3).

[0057]

number

[0058]

number

[0059]

number

[0060] In equations (1), (2), and (3), the subscript n is used to distinguish whether the value being looked at is from one month ago (previously) or this month (this time).

[0061] X0 indicates the amount of fuel refueled this time. X1 indicates the amount of fuel remaining in the fuel tank 15 one month after the initial refueling. This is updated using formula (1). It is calculated by subtracting the amount of fuel used from last month to this month, U, from the amount of fuel remaining in last month (month 0), S (X0). However, the amount of fuel used, U, is calculated by multiplying the amount of fuel remaining, S, by the proportion of X0 (U x X0 / (X0+X1+X2+X3)).

[0062] X2 indicates the amount of fuel remaining in the fuel tank two months after the initial refueling. This is updated using equation (2). As with equation (1), it is calculated by subtracting the amount of fuel used from last month to this month, U, from the amount of fuel remaining in the previous month (first month), S(X1). However, the amount of fuel used, U, is calculated by multiplying the amount of fuel remaining, S, by the proportion of X1 (U x X1 / (X0 + X1 + X2 + X3)).

[0063] X3 indicates the amount of fuel remaining in the fuel tank more than three months after the initial refueling. This is updated using equation (3). As with equation (1), it is calculated by subtracting the amount of fuel used from last month to this month, U, from the amount of fuel remaining in the previous month (second month), S(X2). However, the amount of fuel used, U, is calculated by multiplying the amount of fuel remaining, S, by the proportion of X2 (U x X2 / (X0 + X1 + X2 + X3)).

[0064] Furthermore, in the case of X3, since the previous month may be the third month, as shown in formula (3), the remaining fuel amount S(X3) of last month is multiplied by the amount (U×X3 / (X0+X1+X2+X3)) corresponding to the proportion of X3 in the amount of fuel used from last month to this month. Then, the calculation result when the previous month was the second month is added to the calculation result when the previous month was the third month.

[0065] The change in the remaining fuel amount (X1, X2, X3) for each elapsed period since refueling, which is updated by the update unit 27 described above, is shown by the dotted arrows in the table of FIG. 4. In this embodiment, the deterioration period is set to three months from the time of refueling. Therefore, the engine maintenance mode is started or canceled by comparing whether the value of X3 is greater than or less than the deterioration determination threshold. In this embodiment, the capacity of the fuel tank 15 is 56 L (liters), and 33.6 L, which is 60% of the tank capacity, is set as the deterioration determination threshold.

[0066] As shown in the example of calculating the amount of deteriorated fuel in Figure 4, even if new fuel (for example, 20 L) is not refueled all at once within the three-month deterioration period from the initial refueling, the engine maintenance mode will not be activated, but will be activated in the fourth month.

[0067] Although the above embodiment has been described with reference to an example in which the unit period is one month, it may be set to half a month, one week, or one day. Also, the unit period may be changed depending on whether the engine maintenance mode is active or not, so that the determination to cancel the engine maintenance mode can be made quickly.

[0068] According to the configuration of the above embodiment, the degraded fuel calculation unit 23 manages the amount of fuel refueled X0 and the amount of fuel used U for each unit period, which is a predetermined fixed period (one month), and updates the amounts of remaining fuel X1, X2, and X3 remaining in the fuel tank 15 for each elapsed period since refueling, which were calculated for the previous unit period, to calculate these remaining fuel amounts for the current unit period, so that the amount of degraded fuel that has been degraded for a period of three months or more can be calculated with high accuracy. Therefore, it is possible to accurately start and cancel the engine maintenance mode.

[0069] Furthermore, since the amount of remaining fuel since refueling is updated and calculated for each unit period by the update unit 27, the amount of remaining fuel since refueling can be accurately calculated.

[0070] In some embodiments, as shown in FIG. 1, the control device 21 includes an engine maintenance mode prediction unit 29 that predicts when the amount of degraded fuel will reach or exceed the degradation determination threshold, and further includes a display control unit 31 that controls a display unit 33 that notifies the driver of the start time of the engine maintenance mode predicted by the engine maintenance mode prediction unit 29.

[0071] A predetermined fixed period is used as the unit period, and the remaining fuel amount is updated for each unit period to determine whether the amount of deteriorated fuel that has reached the deterioration period or longer will exceed the deterioration determination threshold. Therefore, depending on the length of the unit period, it can be set to, for example, half a month, one week, or one day, and by understanding the changing state of the amount of deteriorated fuel in the fuel tank 15, it is possible to predict when the amount of deteriorated fuel will exceed the deterioration determination threshold.

[0072] For example, at the end or start of a unit period, the amount of deteriorated fuel in the next unit period is estimated using the average values of the amount of fuel used and the amount of fuel supplied in the past unit period, using the above-mentioned update formulas (1) to (3), and it is determined whether the amount is equal to or greater than the deterioration determination threshold, thereby predicting the timing of starting the engine maintenance mode. Furthermore, the amount of fuel supplied is changed in several steps and the amount of fuel required to avoid starting the engine maintenance mode is estimated.

[0073] Therefore, the engine maintenance mode prediction unit 29 predicts the start time of the engine maintenance mode and further predicts the amount of fuel required to avoid the start of the engine maintenance mode, and the display control unit 31 can display the prediction results on the display screen 35 of the display unit 33.

[0074] The display timing is to periodically display the result at the end or start of the unit period in accordance with the timing of the estimation of the amount of degraded fuel in the next unit period, or the result of the prediction may be displayed by the driver operating a display switch provided near the driver's seat.

[0075] 7 and 8, the display unit 33 is installed in an instrument panel in front of the driver's seat and displays the vehicle speed, the charge state of the drive battery, etc. on a display screen 35 in a combination meter. Alternatively, the display may be displayed on a navigation display of a navigation system (not shown).

[0076] The display format on the display screen 35 may be, for example, as shown in Fig. 7, a format in which a calendar 37 is displayed to highlight the predicted engine maintenance mode start date and to display the required amount of fuel, or, if there are only a few days until the predicted engine maintenance mode start date, a format in which the required amount of fuel is displayed in large letters as shown in Fig. 8. Furthermore, a graph showing the date of refueling and the amount of fuel refueled, and the change in the amount of fuel elapsed since refueling, may be displayed.

[0077] According to the configuration of this embodiment, it is possible for the engine maintenance mode prediction unit 29 to predict the timing at which the engine maintenance mode will be initiated and the amount of fuel required to avoid this. Furthermore, the display control unit 31 can accurately notify the driver of the predicted timing at which the engine maintenance mode will be initiated, thereby encouraging the driver to refuel.

[0078] (Another embodiment) Next, another embodiment will be described with reference to Figures 5 and 6. The other embodiment differs from the first embodiment in the degraded fuel calculation unit 41. In the first embodiment, the degraded fuel calculation unit 23 manages the amount of fuel supplied and the amount of fuel used for each unit period, with a predetermined fixed period being used as a unit period, whereas in the other embodiment, the degraded fuel calculation unit 41 manages the amount of fuel supplied and the amount of fuel used since the last time the fuel was supplied, at each time of refueling. In the other embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0079] The degraded fuel calculation unit 41 manages the amount of fuel refueled and the amount used since the previous refueling each time refueling occurs, and has an update unit 43 that updates the amount of remaining fuel from the previous refueling calculated at the time of refueling each time refueling occurs to calculate the amount of remaining fuel at the time of current refueling, and the update unit 43 calculates the amount of degraded fuel, which is the amount of remaining fuel that has been left for more than the degradation period since refueling.

[0080] The control flow in the degraded fuel calculation unit 41 and the update unit 43 of another embodiment will be described with reference to the control flowchart of FIG.

[0081] First, in step S21, it is determined whether refueling has occurred. If yes, the answer is Yes and the process proceeds to step S22, where the amount of refueled fuel is obtained. In step S21, No is repeated until refueling has occurred. In the next step S23, the amount of fuel used since the previous refueling is obtained. In the next step S24, the amount of deteriorated fuel is calculated. Thereafter, steps S6 to S9 are the same as those in the embodiment shown in FIG. 2.

[0082] The calculation of the amount of degraded fuel in step S24 is performed according to the flow of the control flowchart of the subroutine in Fig. 6. In Fig. 6, first, in step S31, the amount of remaining fuel from the previous refueling calculated at the time of the previous refueling is obtained. In the next step S32, the amount of fuel used from the previous refueling to the current refueling, obtained in step S23, is obtained.

[0083] In the next step S33, the amount of fuel used obtained in step S32 is subtracted from the amount of remaining fuel obtained in step S31 to update the amount of remaining fuel calculated at the previous refueling, and the amount of remaining fuel at the current refueling time since the previous refueling is calculated.

[0084] In the next step S34, steps S31 to S33 are repeated for the deterioration period or more to calculate the deteriorated fuel amount, which is the remaining fuel amount after the deterioration period or more has elapsed.

[0085] Furthermore, the engine maintenance mode prediction unit 29 calculates the amount of deteriorated fuel each time refueling occurs, and compares it with the deterioration determination threshold to determine whether it is equal to or greater than the deterioration determination threshold. This makes it possible to predict the start time of the engine maintenance mode based on the prediction of the amount of deteriorated fuel at the next refueling.

[0086] For example, assuming that the amount of deteriorated fuel will be equal to or greater than the deterioration determination threshold at the time of the next refueling, the amount of fuel used U until the next refueling is calculated backward using equations (1) to (3) in the update unit 43, and the day when the amount of fuel used U will be equal to or greater than the deterioration determination threshold, which is assumed to be the time of the next refueling, is predicted from the amount of fuel used U, and the amount of fuel required to avoid starting the engine maintenance mode is predicted. Note that equations (1) to (3) described in one embodiment are for each unit period, but can also be similarly applied to each refueling period in other embodiments.

[0087] Furthermore, the display control unit 31 displays the prediction result on the display screen 35 of the display unit 33, as in the first embodiment. The display timing is such that the prediction is made and displayed at the time of refueling. Alternatively, the prediction result may be displayed by the driver operating a display switch provided near the driver's seat.

[0088] According to the configuration of the other embodiment described above, data on the amount of fuel refueled and the amount of fuel used since the previous refueling are acquired each time refueling is performed, so that this data can be acquired without a time lag from the actual time of refueling, and therefore the amount of degraded fuel that has been used for more than the degradation period since the previous refueling can be calculated with high accuracy.

[0089] Furthermore, since the update unit 43 updates the remaining fuel amount calculated at the previous refueling by the previous update unit 43 each time refueling is performed to calculate the remaining fuel amount at the current refueling time, it is possible to accurately calculate the amount of deteriorated fuel that has been in use for a deterioration period or more since the previous refueling. Therefore, the display control unit 31 can accurately notify the driver of the predicted start time of the engine maintenance mode, and encourage the driver to refuel. [Explanation of symbols]

[0090] 1 vehicle 3 Engine 5. Drive motor 7. Generator 9. Drive battery (battery) 11 wheels 13 Transaxle 15 Fuel Tank 17 Motor control unit 19 Engine Control Unit 21 Control device 23, 41 Degraded fuel calculation section 25 Deteriorated fuel determination section 27, 43 Update section 29 Engine maintenance mode prediction section 33 Display section 35 Display screen 31 Display control unit

Claims

1. a drive motor that operates using power supplied from the battery and provides driving force to the vehicle; an engine that operates using fuel supplied from a fuel tank and provides driving force to the vehicle or the generator, A control device for a plug-in hybrid vehicle that implements an engine maintenance mode that forcibly operates the engine to prompt the refueling of new fuel in order to prevent fuel deterioration due to the engine being left unused for a long period of time, The control device includes a degraded fuel calculation unit that calculates the amount of degraded fuel that has been degraded for a predetermined period of time or more since refueling based on the amount of fuel supplied and the amount of fuel used; a degraded fuel determination unit that determines whether the amount of degraded fuel calculated by the degraded fuel calculation unit is equal to or greater than a predetermined degradation determination threshold, When the determination result of the deteriorated fuel determination unit is equal to or greater than the deterioration determination threshold, the engine maintenance mode is started or, if started, is continued; when the determination result is less than the deterioration determination threshold, the engine maintenance mode is not started or, if started, is canceled; The degraded fuel calculation unit manages the amount of fuel refueled and the amount of fuel used since the previous refueling at each refueling time, and the degraded fuel calculation unit has an update unit that updates the amount of remaining fuel since the previous refueling time calculated at each refueling time to calculate the amount of remaining fuel at the current refueling time, and calculates the amount of degraded fuel, which is the amount of remaining fuel that has elapsed since the previous refueling time for a degradation period or more, by the update unit, The updating unit updates the remaining fuel amount by subtracting the "amount of fuel used from the previous refueling to the current refueling" from the "amount of remaining fuel from the previous refueling calculated at the previous refueling." A control device for a plug-in hybrid vehicle.

2. The degraded fuel calculation unit manages the amount of fuel supplied and the amount of fuel used for each unit period, with a predetermined fixed period being a unit period, and the degraded fuel calculation unit has an update unit that updates the amount of fuel remaining since the time of refueling calculated in the previous unit period for each unit period to calculate the amount of fuel remaining in the current unit period, and calculates the amount of degraded fuel, which is the amount of fuel remaining for which a degradation period or more has elapsed since the time of refueling, by the update unit. The control device for a plug-in hybrid vehicle according to claim 1.

3. The updating unit updates the remaining fuel amount by subtracting the "amount of fuel used in the current unit period" from the "amount of remaining fuel since refueling calculated in the previous unit period." The control device for a plug-in hybrid vehicle according to claim 2.

4. The control device includes an engine maintenance mode prediction unit that predicts a time when an engine maintenance mode will be started based on the amount of degraded fuel calculated by the degraded fuel calculation unit. The control device for a plug-in hybrid vehicle according to any one of claims 1 to 3.

5. a display control unit that controls a display unit that notifies a driver of the start time predicted by the engine maintenance mode prediction unit; The control device for a plug-in hybrid vehicle according to claim 4.

Images