JP4692467B2 - HYBRID VEHICLE ENGINE CONTROL DEVICE AND HYBRID VEHICLE ENGINE CONTROL METHOD - Google Patents

Description

  The present invention relates to an engine control apparatus and an engine control method for a hybrid vehicle, and in particular, the engine is automatically stopped when a predetermined condition is satisfied while the vehicle is running, and a battery is used when the constant condition is satisfied after the engine is stopped. The present invention relates to an engine control device and an engine control method for a hybrid vehicle having an automatic stop / restart function for automatically restarting the engine.

  A so-called hybrid vehicle using an engine and a motor as drive sources often has an automatic engine stop / restart function from the standpoint of improving fuel consumption. Here, the automatic stop / restart function of the engine means that the engine is automatically stopped when a predetermined condition is satisfied while the vehicle is running, and the engine is automatically operated using a battery when the predetermined condition is satisfied after the engine is stopped. This is a function to restart.

  In this restart, the engine is started using a battery mounted on the vehicle. By the way, since the output characteristics of a battery generally deteriorate at a low temperature, depending on the capacity of the battery, even if the engine can be started at room temperature, the engine cannot be restarted at a low temperature. Therefore, as shown in Patent Document 1, a predetermined temperature is determined in consideration of the temperature characteristics of the battery, and engine stop is prohibited even if the engine automatic stop condition is satisfied below that temperature.

  However, the method of setting the predetermined temperature and prohibiting the engine from being uniformly stopped is when the battery is new or has a sufficient capacity to start the engine even at the predetermined temperature or lower, such as immediately after full charge. However, the engine stop is prohibited. In this case, the purpose of improving the fuel consumption by the automatic engine stop / restart function is insufficient. Therefore, it is conceivable to estimate the state of the battery by some method and determine whether or not to prohibit the engine stop according to the result.

  For example, Patent Document 2 discloses that a starter motor is installed in a motorcycle having an engine automatic stop start device that stops an engine in response to a predetermined stop condition and restarts in response to a predetermined start operation after the stop. Is energized at a predetermined timing other than when the engine is restarted, and it is disclosed to determine whether or not to allow the engine to be automatically stopped based on the battery voltage at that time.

  In Patent Document 3, in the engine automatic stop and start device similar to Patent Document 1, while the multiphase motor for cranking the engine is stopped, the driving force of the multiphase motor is minimized, and the energization is equivalent to the engine start. It is disclosed that a driving current is supplied to each phase in a pattern, and the capacity of the battery is determined based on at least one of the battery voltage and the driving current during the supply of the driving current.

JP 2004-44469 A JP 2002-115578 A JP 2004-28011 A

  According to the methods described in Patent Documents 2 and 3, it is possible to determine whether or not to prohibit engine stop by checking the battery capacity at that time instead of prohibiting automatic engine stop at a uniform temperature. However, in the method of Patent Document 2, when a starter motor dedicated to cranking an engine is provided as in a motorcycle, the capacity of the battery is determined by the battery voltage when the stopped starter motor is energized. Check to determine if the engine can be stopped. Therefore, when an engine and a motor are used as drive sources as in a hybrid vehicle, the method cannot be applied as it is. For example, in a hybrid vehicle, there are cases where both the engine and the motor are operating, and the engine may stop and travel by the motor. Therefore, as in Patent Document 1, the stopped motor is energized. It cannot be determined whether or not the engine stop is prohibited based on the battery voltage at that time. The same applies to the method of Patent Document 3.

  An object of the present invention is to provide an engine control device and an engine control method capable of appropriately executing whether or not to prohibit engine stop in a hybrid vehicle.

The engine control apparatus for a hybrid vehicle according to the present invention automatically stops the engine when a predetermined condition is satisfied while the vehicle is running, and automatically restarts the engine using a battery when the predetermined condition is satisfied after the engine is stopped. and automatic stop and restart means for the vehicle speed determining means for car two speed is determined whether a predetermined predetermined vehicle speed or more as does not hinder the start of the engine, the vehicle speed by a vehicle speed determining means When it is determined that the vehicle speed is equal to or higher than a predetermined vehicle speed, battery temperature determination means for determining whether or not the battery temperature is equal to or lower than a predetermined temperature, and the battery temperature is determined to be equal to or lower than the predetermined temperature. When it is determined , the engine is temporarily stopped and then the engine is temporarily started to detect a change in battery voltage, Battery voltage determining means for determining whether or not the change in battery voltage before and after the time activation is less than or equal to a predetermined threshold ; when the battery voltage change is determined by the battery voltage determining means to be less than or equal to the threshold; and When the battery temperature determining means determines that the battery temperature is not lower than the predetermined temperature, it is determined whether or not the engine automatic stop condition is satisfied, and the engine is stopped when the engine automatic stop condition is satisfied. Engine stop determining means for prohibiting engine stop when it is determined by the determining means that the change in battery voltage is not less than or equal to the threshold, and when the vehicle speed determining means determines that the vehicle speed is not equal to or higher than the predetermined vehicle speed ; , characterized in that it comprises a.

In the engine control apparatus for a hybrid vehicle according to the present invention, it is preferable that the temporary starting means causes the engine to be temporarily started after a predetermined time from the stop of the engine .

The engine control apparatus for a hybrid vehicle according to the present invention automatically stops the engine when a predetermined condition is satisfied while the vehicle is running, and automatically uses the battery to stop the engine when the predetermined condition is satisfied. and automatic stop and restart means to restart, the vehicle speed determining Dedan car both speed is determined whether a predetermined predetermined vehicle speed or more as does not hinder the start of the engine, the vehicle speed determining means When it is determined that the vehicle speed is equal to or higher than a predetermined vehicle speed, battery temperature determination means for determining whether or not the battery temperature is equal to or lower than a predetermined temperature, and the battery temperature is determined to be lower than the predetermined temperature by the battery temperature determination means The engine is temporarily stopped and then the engine is temporarily started to detect a change in the battery voltage; Voltage detecting means for detecting a change in the battery voltage before and after the temporary activation of the battery, and an estimating means for estimating the actual capacity of the battery in the vehicle state based on the detected change in the battery voltage. Features.

Further, the engine control method for a hybrid vehicle according to the present invention automatically stops the engine when a predetermined condition is satisfied while the vehicle is running, and automatically uses the battery when the predetermined condition is satisfied after the engine is stopped. In a vehicle having an automatic stop / restart function to be restarted, a vehicle speed determination step for determining whether or not the vehicle speed is equal to or higher than a predetermined vehicle speed that is determined in advance as having no trouble in starting the engine ;
A battery temperature determining step for determining whether or not the battery temperature is equal to or lower than a predetermined temperature set in advance when the vehicle speed is determined to be equal to or higher than a predetermined vehicle speed determined in the vehicle speed determining step;
A temporary start step for temporarily stopping the engine and then detecting the change in the battery voltage when the battery temperature is determined to be lower than or equal to a predetermined temperature in the battery temperature determination step; A battery voltage determining step for determining whether or not a change in the battery voltage before and after the temporary start of the engine is equal to or less than a predetermined threshold, and when the change in the battery voltage is determined to be equal to or less than the threshold in the battery voltage determining step When the battery temperature determination step determines that the battery temperature is not lower than the predetermined temperature, it is determined whether or not the engine automatic stop condition is satisfied, and the engine is stopped when the engine automatic stop condition is satisfied. When it is determined in the battery voltage determination step that the change in the battery voltage is not less than or equal to the threshold value, and in the vehicle speed determination step, the vehicle speed is equal to or higher than the predetermined vehicle speed. Characterized in that it comprises a, and the engine stop determination step for prohibiting the engine stops when it is determined that it is not.

  According to at least one of the above configurations, an engine control device for a hybrid vehicle having means for automatically stopping and restarting the engine causes the engine to temporarily start to detect a change in battery voltage, and temporarily starts the engine. It is determined whether or not to prohibit the engine stop based on the change in battery voltage before and after. In this way, the engine stop is not prohibited uniformly depending on the temperature condition etc., but the engine stop and restart are actually performed, and whether or not the engine stop is prohibited is determined by the state of the battery at the time of the engine restart. In a hybrid vehicle, it is possible to appropriately determine whether or not to prohibit engine stop.

  In addition, when the change in the battery voltage before and after the engine is temporarily started is within the threshold range, the engine stop is not prohibited, so that the current battery capacity is sufficient and the battery voltage drops due to the engine temporary start. When the engine capacity is low, the engine can be stopped and fuel consumption can be improved. On the other hand, when the current battery capacity is insufficient and the drop in battery voltage due to temporary engine startup exceeds the threshold range, the engine stop can be prohibited. In this way, it is possible to appropriately determine whether to prohibit engine stop.

  Also, only when the vehicle speed is higher than the vehicle speed at which there is no hindrance to starting the engine and the battery temperature is lower than a predetermined temperature that is arbitrarily determined in advance, the engine is stopped based on the change in the battery voltage due to the temporary startup of the engine. Judgment is made on whether or not to prohibit. As a result, if the battery temperature is sufficiently high and the battery capacity does not hinder engine startup in view of the temperature characteristics of the battery, the engine should be stopped without starting the engine temporarily. Can do. Therefore, the determination of whether or not to stop the engine is simplified.

  In addition, according to at least one of the above-described configurations, an engine control device for a hybrid vehicle having means for automatically stopping and restarting the engine causes the engine to be temporarily started to detect a change in battery voltage, and the engine temporarily Based on the change in battery voltage before and after automatic activation, the actual capacity of the battery in the vehicle state is estimated. Thereby, the actual capacity of the battery in the current vehicle state of the hybrid vehicle can be appropriately estimated. The estimated actual capacity of the battery is used for determining whether or not to stop the engine.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a hybrid vehicle using an engine and a motor / generator as drive sources will be described. However, instead of the motor / generator, a motor and a generator may be provided separately.

  FIG. 1 is a block diagram of an engine control system 10 for a hybrid vehicle. The engine control system 10 includes an engine 14 as a hybrid vehicle drive source 12, a motor / generator 16, a high-voltage battery 18 connected to the motor / generator 16, and a battery temperature detection unit 20 provided in the high-voltage battery 18. And the battery voltage detection part 22 and the engine control apparatus 30 are comprised.

  The engine 14 and the motor / generator 16 of the drive source 12 are used for running the hybrid vehicle. The operation of the engine 14 and the operation of the motor / generator 16 are executed under the control of the engine control device 30 according to the state of the vehicle in consideration of, for example, fuel consumption. For example, in order to improve fuel efficiency, the motor / generator 16 is operated as a drive motor in a stable running state to stop the engine 14 and, when acceleration or the like is necessary, the engine 14 is additionally operated. Etc. When the vehicle is braked, the motor / generator 16 is operated as a generator to convert regenerative energy into electric power and store it in the high voltage battery 18.

  The high-voltage battery 18 is a secondary battery mounted on a vehicle and supplies electric power to the motor / generator 16 to operate as an electric motor. When operating as a generator as described above, the regenerative energy is used as electric power. receive. The high voltage battery 18 is also a battery used as a power source for starting the engine 14. As the high voltage battery 18, an assembled battery in which a plurality of nickel metal hydride cells are combined or an assembled battery in which a plurality of lithium ion cells are combined can be used. A boost converter, an inverter circuit, and the like are provided between the high voltage battery 18 and the motor / generator 16, but are not shown in FIG. 1.

  The battery temperature detection unit 20 has a function of detecting the temperature related to the high voltage battery 18. As described above, since the assembled battery in which a plurality of single cells is combined is used as the high voltage battery 18, the temperature is detected at a plurality of locations of the assembled battery. The assembled battery temperature is affected by the temperature of the battery itself due to the battery chemical reaction accompanying the charging / discharging of the battery together with the outside air temperature. In particular, since there is a temperature difference between the central portion and both ends of the assembled battery, at least the temperatures of these parts of the assembled battery are detected. Further, as the outside air temperature, a temperature of a vehicle part that can represent the environmental temperature of the entire assembled battery can be used. The battery temperature has such complicated contents, but typically, for example, the temperature at the center of the assembled battery can be set as the battery temperature. Or it is good also as what represents battery temperature with the external temperature regarding the high voltage battery 18. FIG. The detected battery temperature data is transmitted to the engine control device 30 via an appropriate data interface.

  The battery voltage detection unit 22 has a function of detecting a voltage related to the high voltage battery 18. As described above, the high-voltage battery 18 is an assembled battery in which a plurality of single cells are combined. Therefore, depending on the purpose, the terminal voltage of each single cell is monitored. Here, regarding engine restart, it is only necessary to be able to detect a battery voltage that can represent the current battery capacity. For example, the voltage between both terminals of the high-voltage battery 18 is simply used as the battery voltage. be able to. The detected battery voltage data is transmitted to the engine control device 30 via an appropriate data interface.

  The engine control device 30 has a function of controlling the operation of the drive source 12 based on the transmitted battery temperature data, battery voltage data, and the like. In that sense, it is a drive source control device rather than an engine control device, or can be called a hybrid vehicle control device. Here, paying attention mainly to the function of executing control of the engine, the process proceeds with the name of the engine control device 30. The engine control device 30 roughly has two functions. One is a function executed by the engine automatic stop / restart module 32. Specifically, the engine is automatically stopped when a predetermined condition is satisfied while the vehicle is traveling, and a certain condition is satisfied after the engine is stopped. This function automatically restarts the engine using the battery. Here, the battery refers to the high voltage battery 18. Another function is a function that estimates the battery capacity in the state where the vehicle is placed, for example, the state of the vehicle that is running, and determines whether to stop the engine or prohibit the engine from being stopped. Specifically, this function is executed by the battery temperature determination module 34, the engine temporary start module 36, the battery voltage determination module 38, and the engine stop prohibition determination module 40.

  Such an engine control device 30 can be configured by a vehicle computer. The engine control device 30 may be configured by an independent computer, or may be included in the function of another vehicle computer mounted on the vehicle. These functions of the engine control device 30 can be realized by software, specifically, by executing an engine control program of the corresponding hybrid vehicle. Some of these functions can also be realized by hardware.

  The operation of the engine control system 10 having the above configuration, particularly each function of the engine control device 30, will be described in detail with reference to the flowchart of FIG. FIG. 2 is a flowchart showing a procedure for engine control, in particular, engine control when a predetermined condition for engine stop is satisfied. Each of these procedures corresponds to each processing procedure of the above-described hybrid vehicle engine control program.

  When the vehicle is running, the operation of the engine 14 and the operation of the motor / generator 16 are combined and selected according to the state of the vehicle as described above. Here, a description will be given from the state where the vehicle is in an engine-driven running state (S10). When the vehicle is in an engine-driven running state, at least the engine 14 is operating, and the motor / generator 16 may be operating as an electric motor, may be operating as a generator, or May stop at all.

  As described above, since this hybrid vehicle has an engine automatic stop / restart function, it is determined whether or not a predetermined condition for automatically stopping the engine 14 is satisfied during engine driving. Will be. This determination may be performed in a constantly monitored state or may be performed by appropriate sampling. This function is executed by the engine automatic stop / restart module 32 of the engine control device 30.

  A predetermined condition for automatically stopping the engine 14 and a certain condition for automatically restarting the engine after the engine 14 stops are set according to the specifications of the hybrid vehicle. For example, the required power determined from the sum of the electric load required by the vehicle based on the driving of the motor / generator, the operation of the air conditioner, etc., and the work amount of the wheel obtained from the depression amount of the accelerator pedal and the vehicle speed, A predetermined condition for automatic stop of the engine 14 and a constant condition for automatic restart can also be set by comparison with a threshold value set as a start condition.

Here, in the prior art, when it is determined that the predetermined condition for the automatic engine stop is satisfied during engine driving, it is determined whether or not the battery temperature is equal to or lower than the predetermined temperature T ₀ , and the battery temperature is equal to the predetermined temperature T _0. However, if the temperature is lower than or equal to the predetermined temperature T ₀ , the zero capacity of the high voltage battery 18 may be insufficient. The engine stop is prohibited.

In the flowchart of FIG. 2, the engine capacity is not prohibited uniformly, but the battery capacity in the current state of the vehicle is first monitored. Based on the result, it is determined whether or not the engine stop is prohibited. For this purpose, it is first determined whether or not the vehicle speed is equal to or higher than a vehicle speed V ₀ that has been determined in advance as being satisfactory for starting the engine (S12). In the process of S12, in the subsequent processes, the engine 14 is temporarily stopped in consideration of the establishment of the engine automatic stop condition, but the engine 14 is temporarily started in order to check the battery capacity of the vehicle at that time. This is based on the condition that the vehicle is in a vehicle speed range where the speed does not hinder its temporary activation. The predetermined vehicle speed V ₀ can be set to, for example, 15 km / h. This is because at such a vehicle speed, the engine 14 does not have a very large load, and therefore, the power supply from the high voltage battery 18 is not so large.

In S12, if the vehicle speed is not determined and is greater than or equal _to V _0, the process proceeds to S26, the engine stop is prohibited. That is, the engine drive traveling returns to S10 regardless of the engine stop condition being satisfied. When the vehicle speed is determined to be greater than or equal _to V ₀ in S12, then whether a predetermined temperature T ₀ or less the battery temperature is previously determined arbitrarily is determined (S14). This function is executed by the battery temperature determination module 34 of the engine control device 30.

Significance of S14 in step is when the battery temperature is not determined from the predetermined temperature T ₀ or less. That is, the battery temperature is not determined from the predetermined temperature T ₀ or less, when exceeding a predetermined temperature T _0, the high voltage battery 18 is sufficiently warmed up to have the battery temperature is sufficiently high, as seen from temperature characteristics of the battery Since it is considered that the battery capacity does not hinder the start of the engine, the engine stop prohibition is not performed only by that fact, and the subsequent steps are skipped and the process proceeds to S22. As a result, in order to determine whether or not the engine stop is prohibited, the procedure from S16 described below becomes unnecessary. That is, when it is not determined that the battery temperature is equal to or lower than the predetermined temperature T ₀ , the determination of whether or not the engine stop is prohibited is simplified in the step S14. As the predetermined temperature T ₀ , a battery temperature set to uniformly prohibit the engine from being stopped in the conventional technique can be used.

In S14, when the battery temperature is determined that the predetermined temperature _{T 0} or less, wherein once the engine 14 is stopped (S16). Then, after an appropriate time, the engine 14 is temporarily started (S18). This function is executed by the engine temporary activation module 36 of the engine control device 30. Then, before and after the engine is temporarily started, a change in the battery voltage is monitored, and it is determined whether or not the change in the voltage is within a predetermined threshold ΔV (S20). This function is executed by the battery voltage determination module of the engine control device 30.

  This is shown in FIG. In FIG. 3, the horizontal axis represents time and the vertical axis represents the battery voltage. From the engine driving state (S10), the engine is stopped (S16). It is a figure which shows typically the change of the battery voltage when S18) is performed. A suitable time can be several seconds. Here, for example, when the capacity of the high-voltage battery 18 is sufficient, such as when the battery is a new battery and there is almost no deterioration over time of the capacity or immediately after full charge, the voltage characteristic 50 is Even if automatic activation is performed, there is little change in battery voltage before and after that. The same characteristics as when the battery temperature is sufficiently high are shown. On the other hand, the voltage characteristic 52 when the capacity of the high-voltage battery 18 is not sufficient, such as when the battery is old and the capacity has deteriorated over time, or when the battery is not fully charged, or when there is a lot of discharge, etc. Due to the temporary startup of the engine 14, the voltage drop is large, and it takes time to recover. Note that the same characteristics are exhibited when the battery temperature is too low. Therefore, the actual capacity of the high-voltage battery 18 can be relatively estimated based on the magnitude of the voltage change before and after the temporary startup of the engine 14.

  Returning to FIG. 2 again, a threshold value ΔV is set in advance, and the voltage change before and after the temporary startup of the engine 14 is compared with this threshold value (S20). When the voltage change is within the threshold range, it is determined that the engine can be stopped. On the other hand, when the voltage change exceeds the threshold range, it can be determined that the engine stop is prohibited (see S26). The threshold value ΔV can be determined experimentally. This determination is performed by the function of the engine stop prohibition determination module 40 of the engine control device 30.

  If it is determined in S20 that the engine can be stopped, it is determined here whether or not a predetermined condition for the automatic engine stop is satisfied (S22). That is, it is preferable that the steps from S12 to S20 are repeatedly performed at an appropriate sampling time. When a predetermined condition for automatically stopping the engine is satisfied, the engine 14 is stopped (S24).

  When the engine is stopped in S24, the establishment of a certain condition for performing automatic restart of the engine 14 is monitored thereafter. When this certain condition is satisfied, the engine is driven and the process returns to S10. Note that when the engine stop prohibition is executed in S26, the engine 14 remains operating, which is the state of engine drive running (S10). In this way, when returning to S10, the steps after S12 are repeated again.

When the engine stop prohibition is executed in S26, it is determined that the actual capacity of the high voltage battery 18 is insufficient, but when the cause is the low temperature of the battery, the battery temperature is monitored. The engine can also be stopped when an appropriate battery temperature is reached. According to this method, the engine stop prohibition can be canceled by simplifying the steps from S12 to S20. An appropriate battery temperature for canceling the engine stop prohibition can be set to a temperature that is, for example, 1 ° C. higher than the current battery temperature. Of course, it may be an appropriate rising temperature other than 1 ° C. Further, it may be an engine stop prohibition release upon reaching the predetermined temperature T ₀ as described above.

  As described above, when the engine stop condition is satisfied, the state of the battery in that state is determined, and when it is determined that the battery capacity is sufficient for restarting the engine, the engine stop is not prohibited. In the vehicle, it is possible to appropriately determine whether to prohibit engine stop. In particular, when the battery is at a low temperature, the engine stop is not prohibited uniformly and the engine stop can be executed in accordance with the state of the battery, so that the fuel efficiency of the hybrid vehicle can be improved more appropriately.

1 is a block diagram of an engine control system for a hybrid vehicle including an engine control device according to an embodiment of the present invention. 4 is a flowchart showing a procedure for engine control in the embodiment according to the present invention. In embodiment which concerns on this invention, it is a figure which shows typically the change of a battery voltage when an engine is temporarily started.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Engine control system, 12 Drive source, 14 Engine, 16 Motor generator, 18 High voltage battery, 20 Battery temperature detection part, 22 Battery voltage detection part, 30 Engine control apparatus, 32 Engine automatic stop / restart module, 34 Battery Temperature determination module, 36 Engine temporary startup module, 38 Battery voltage determination module, 40 Engine stop prohibition determination module, 50, 52 Voltage characteristics.

Claims (4)

An automatic stop / restart means for automatically stopping the engine when a predetermined condition is satisfied while the vehicle is running, and automatically restarting the engine using a battery when the predetermined condition is satisfied ;
A vehicle speed determining means for car two speed is determined whether a predetermined predetermined vehicle speed or more as does not hinder the start of the engine,
Battery temperature determining means for determining whether or not the battery temperature is equal to or lower than a predetermined temperature set in advance when the vehicle speed is determined to be equal to or higher than a predetermined vehicle speed determined by the vehicle speed determining means;
Temporary starting means for temporarily stopping the engine and detecting the change in the battery voltage when the battery temperature determining means determines that the battery temperature is equal to or lower than a predetermined temperature ; ,
Battery voltage determination means for determining whether or not a change in battery voltage before and after the temporary start of the engine is equal to or less than a predetermined threshold;
Whether or not the automatic engine stop condition is satisfied when the battery voltage determining means determines that the change in the battery voltage is equal to or lower than the threshold, and when the battery temperature determining means determines that the battery temperature is not lower than the predetermined temperature. The engine is stopped when the automatic engine stop condition is satisfied, and when the battery voltage determining means determines that the change in the battery voltage is not less than the threshold value, and the vehicle speed determining means determines that the vehicle speed is the predetermined vehicle speed. Engine stop determination means for prohibiting engine stop when it is determined that the above is not the case ,
An engine control device for a hybrid vehicle, comprising: The engine control apparatus for a hybrid vehicle according to claim 1,
The engine control device for a hybrid vehicle, wherein the temporary starting means causes the engine to be temporarily started after a predetermined time from when the engine is stopped . An automatic stop / restart means for automatically stopping the engine when a predetermined condition is satisfied while the vehicle is running, and automatically restarting the engine using a battery when the predetermined condition is satisfied;
A vehicle speed determination stage for determining whether or not the vehicle speed is equal to or higher than a predetermined vehicle speed that has been determined in advance as being satisfactory for starting the engine;
Battery temperature determining means for determining whether or not the battery temperature is equal to or lower than a predetermined temperature set in advance when the vehicle speed is determined to be equal to or higher than a predetermined vehicle speed determined by the vehicle speed determining means;
Temporary starting means for temporarily stopping the engine and detecting the change in the battery voltage when the battery temperature determining means determines that the battery temperature is equal to or lower than a predetermined temperature; ,
Voltage detecting means for detecting a change in battery voltage before and after the temporary start of the engine;
Estimating means for estimating the actual capacity of the battery in the vehicle state based on the detected change in the battery voltage;
Engine control apparatus for a hybrid vehicle comprising: a. In a vehicle having an automatic stop / restart function that automatically stops the engine when a predetermined condition is satisfied while the vehicle is running, and automatically restarts the engine using a battery when the predetermined condition is satisfied after the engine stops , A vehicle speed determination step for determining whether or not the vehicle speed is equal to or higher than a predetermined vehicle speed that is determined in advance as being satisfactory for starting the engine ;
A battery temperature determining step for determining whether or not the battery temperature is equal to or lower than a predetermined temperature set in advance when the vehicle speed is determined to be equal to or higher than a predetermined vehicle speed determined in the vehicle speed determining step;
A temporary start step for temporarily stopping the engine and then detecting the change in the battery voltage when the battery temperature is determined to be lower than or equal to a predetermined temperature in the battery temperature determination step ; ,
A battery voltage determination step for determining whether or not a change in battery voltage before and after the temporary startup of the engine is equal to or less than a predetermined threshold;
Whether or not the automatic engine stop condition is satisfied when it is determined in the battery voltage determination step that the change in battery voltage is less than or equal to the threshold value, and when the battery temperature determination step determines that the battery temperature is not lower than the predetermined temperature The engine is stopped when the engine automatic stop condition is satisfied, and when it is determined in the battery voltage determination step that the change in the battery voltage is not less than the threshold value, and in the vehicle speed determination step, the vehicle speed is a predetermined vehicle speed. An engine stop determination step for prohibiting the engine stop when it is determined that it is not above ,
An engine control method for a hybrid vehicle, comprising :

Images