JP2011246042A - Device for control of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for control of a hybrid vehicle that can quickly consume reservoir fuel unsuitable for outside air temperature in the hybrid vehicle with an internal combustion engine and an electric motor as power sources.SOLUTION: Threshold air temperatures T1 and T2 corresponding to fuel density of reservoir fuel are computed (step 100). It is determined whether outside air temperature T detected by a temperature sensor 34 is higher than the threshold air temperature T1 (step 102). Consequently, when the relation of T>T1 is valid, the EV range is reduced rather than the normal time (step 104). When the relation of T>T1 is not valid, it is determined whether the outside air temperature T is lower than threshold outside air temperature T2 (step 106). Consequently, when the relation of T<T2 is valid, the EV range is reduced rather than the normal time. Also when the relation of T<T2 is not valid, the EV range is returned to that of the normal time.

Description

  The present invention relates to a control device for a hybrid vehicle.

  Hybrid vehicles that use both an internal combustion engine and an electric motor as driving power are widely used. In recent years, a so-called plug-in hybrid vehicle is also known which is configured to be able to charge a battery with an external power source.

  In JP 2009-264138 A, in a hybrid engine system having an engine and a motor, a region R1 driven by only the motor, a region R2 driven only by the engine, A region R3 that is driven by both the motor is set, and as the ethanol concentration of the fuel is higher, the region R2 that is driven only by the engine is expanded to a higher driving force side, and the region that is driven by both the engine and the motor A technique for reducing R3 is disclosed.

JP 2009-264138 A JP 2009-79978 A JP 2008-107098 A

  By the way, in recent plug-in hybrid vehicles, the area of the electric travel mode in which the vehicle travels only with the electric motor is expanded in order to improve the energy efficiency by maximizing the use of the electric power from the battery. That is, in such a vehicle, it is assumed that the opportunity to use the engine is reduced, and thus the fuel in the tank is stored for a long time without being consumed.

  Here, there are various types of fuel to be supplied depending on the season and region. For example, fuel with a high fuel density (so-called summer fuel) is normally distributed in summer. The summer fuel is refined so that the low-temperature evaporability is low in order to suppress vapor lock and evaporation deterioration in a high-temperature environment. For this reason, when summer fuel is stored until winter, there is a risk that startability deteriorates due to use in an environment where the outside air temperature is low.

  On the other hand, fuel with a low fuel density (so-called winter fuel) is widely distributed in winter. Winter fuel is refined so as to have low temperature evaporability in order to suppress deterioration of startability. For this reason, when the winter fuel is stored until the summer, the problem of vapor lock and the deterioration of the evaporation emission becomes conspicuous due to use in an environment where the outside air temperature is high. That is, if the relationship between the properties of the stored fuel (for example, fuel density) and the outside air environment (for example, outside temperature) becomes inappropriate, there is a concern that the emission characteristics, drivability, etc. may be adversely affected.

  The present invention has been made in order to solve the above-described problems. In a hybrid vehicle including an internal combustion engine and an electric motor as power sources, the hybrid vehicle can quickly consume stored fuel that is not suitable for the outside air temperature. An object is to provide a control device.

In order to achieve the above object, a first invention is a control device for a hybrid vehicle including an internal combustion engine and an electric motor as power sources,
A fuel tank for storing fuel supplied to the internal combustion engine;
Fuel property detecting means for detecting the fuel density of the stored fuel stored in the fuel tank;
Setting means for setting an allowable temperature range of the outside air temperature suitable for operation of the internal combustion engine based on the fuel density;
Outside temperature detecting means for detecting outside temperature;
Fuel consumption increasing means for increasing the amount of fuel consumed in the internal combustion engine when the outside air temperature does not belong to the allowable temperature range;
It is characterized by providing.

According to a second invention, in the first invention,
It is possible to switch between an electric travel mode in which driving power is output from the electric motor when the operation of the internal combustion engine is stopped and an engine travel mode in which part or all of the driving power is output from the internal combustion engine. Switching means,
The vehicle travels in the electric travel mode until the required load and the required rotational speed required for traveling exceed a predetermined region on the low load and low rotational side, and when the required load and the required rotational frequency exceed the predetermined region. Further comprises traveling mode control means for traveling in the engine traveling mode,
The fuel consumption increase means reduces the predetermined region when the outside air temperature does not belong to the outside air temperature range as compared with the case where it belongs.

According to a third invention, in the first invention,
It is possible to switch between an electric travel mode in which driving power is output from the electric motor when the operation of the internal combustion engine is stopped and an engine travel mode in which part or all of the driving power is output from the internal combustion engine. Switching means,
Travel mode control means that travels in the electric travel mode until the required drive force required for travel exceeds a predetermined threshold, and travels in the engine travel mode when the required drive force exceeds the threshold. And further comprising
The fuel consumption increase means sets the threshold value to a lower value when the outside air temperature does not belong to the outside air temperature range than when it belongs.

A fourth invention is any one of the first to third inventions,
The setting means sets the upper limit value of the allowable temperature range lower as the fuel density is lower.

According to a fifth invention, in any one of the first to fourth inventions,
The setting means sets the lower limit value of the allowable temperature range higher as the fuel density is higher.

  According to the first invention, when the outside air temperature does not belong to the allowable temperature range of the outside air temperature set corresponding to the fuel density of the stored fuel stored in the fuel tank, the fuel consumed in the internal combustion engine The amount is increased. For this reason, according to the present invention, the stored fuel that is not suitable for the outside air temperature can be consumed quickly.

  According to the second aspect of the invention, by expanding the region in which the engine travel mode is performed, the opportunity for executing the engine travel mode can be increased, so that the amount of fuel consumed in the internal combustion engine can be effectively increased. .

  According to the third aspect of the invention, the threshold for switching from the electric travel mode to the engine travel mode is set low, so that the opportunity for executing the engine travel mode can be increased, so that the amount of fuel consumed in the internal combustion engine is effectively increased. Can be increased.

  According to the fourth invention, the lower the fuel density, the lower the upper limit of the outside air temperature range is set. The lower the fuel density, the higher the content of the low-temperature evaporating component in the fuel. Therefore, the inappropriate temperature range judged from the viewpoint of evaporation is expanded to the low temperature side. According to the present invention, the higher the low-temperature evaporative fuel, the lower the upper limit of the outside air temperature range becomes to the low temperature side, so that stored fuel that is not suitable for the outside air temperature can be consumed quickly.

  According to the fifth aspect, the lower limit value of the outside air temperature range is set higher as the fuel density is higher. The higher the fuel density, the lower the content of the low-temperature evaporating component in the fuel. Therefore, the inappropriate temperature range judged from the viewpoint of startability is expanded to the high temperature side. According to the present invention, the lower the low temperature evaporability of the fuel, the lower the lower limit of the outside air temperature range is narrowed to the high temperature side, so the stored fuel that is not suitable for the outside air temperature can be consumed quickly.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. It is a map which prescribes | regulates EV mode with respect to a fuel density and external temperature. It is a flowchart of the routine performed in Embodiment 1 of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted. The present invention is not limited to the following embodiments.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. A hybrid vehicle 10 shown in FIG. 1 includes an internal combustion engine 12 and an electric motor 14 as a power source for the vehicle. The hybrid vehicle 10 includes a generator 16. The internal combustion engine 12, the electric motor 14, and the generator 16 are connected to each other via a power distribution and integration mechanism 18. A reduction gear 20 is connected to the rotating shaft of the electric motor 14 connected to the power distribution and integration mechanism 18. The speed reducer 20 connects the rotary shaft of the electric motor 14 and the drive shaft 24 connected to the drive wheels 22. The power distribution and integration mechanism 18 can divide the driving force of the internal combustion engine 12 into the generator 16 side and the speed reducer 20 side. The distribution of the driving force by the power distribution and integration mechanism 18 can be arbitrarily changed. The generator 16 can also function as a starter that starts the internal combustion engine 12.

  The hybrid vehicle 10 further includes an inverter 26, a converter 28, and a battery 30. Inverter 26 is connected to generator 16 and motor 14, and is also connected to battery 30 via converter 28. The electric power generated by the generator 16 can be supplied to the electric motor 14 via the inverter 26, or the battery 30 can be charged via the inverter 26 and the converter 28. Further, the electric power charged in the battery 30 can be supplied to the electric motor 14 via the converter 28 and the inverter 26.

  In addition, the battery 30 described above is configured to be charged via the charging circuit 32 by power supplied from an external power source (such as a household power source). That is, the hybrid vehicle 10 of the present embodiment is configured as a so-called plug-in type hybrid vehicle.

  The hybrid vehicle 10 also includes an ECU (Electronic Control Unit) 50. In addition to the components described above, the ECU 50 stores various actuators (fuel injectors, spark plugs, throttle valves, etc.) provided in the internal combustion engine 12, a temperature sensor 34 that detects the outside air temperature, and a fuel tank (not shown). A fuel property sensor 36 that detects the fuel density of the fuel that is being used and other various sensors (such as an air flow meter, an intake air temperature sensor, and a coolant temperature sensor) are electrically connected. As the fuel property sensor 36, for example, an optical sensor disclosed in Japanese Unexamined Patent Application Publication No. 2009-107098 (Patent Document 3) can be used.

  The ECU 50 calculates a required driving force required for traveling of the vehicle based on the vehicle speed, the accelerator opening, and the like. Then, the operations of the internal combustion engine 12 and the electric motor 14 are controlled so that the required driving force is output to the driving wheels 22.

[Operation of Embodiment 1]
The hybrid vehicle 10 of the present embodiment can travel by stopping the operation of the internal combustion engine 12 and rotating the driving wheels 22 only by the driving force of the electric motor 14. This travel mode is hereinafter referred to as “EV travel mode”.

  Further, the hybrid vehicle 10 of the present embodiment can travel by rotating the driving wheels 22 only by the driving force of the internal combustion engine 12, and further, the driving wheels by the driving force of both the internal combustion engine 12 and the electric motor 14. It is also possible to run by rotating the motor 22. Hereinafter, these travel modes are collectively referred to as “engine travel mode”.

  The ECU 50 travels in the EV travel mode in which the internal combustion engine 12 is stopped and the traveling power is output only from the electric motor 14 while the required driving force does not exceed a predetermined threshold (hereinafter referred to as “engine start threshold”). Control to do. On the other hand, when the required driving force exceeds the engine start threshold, the ECU 50 controls the internal combustion engine 12 to start and travel in the engine travel mode. That is, when the required driving force exceeds the engine start threshold value, all of the driving power is output from the internal combustion engine 12, or is shared by the internal combustion engine 12 and the electric motor 14 to output the driving power. .

  In a plug-in hybrid vehicle such as the hybrid vehicle 10 of the present embodiment, the battery 30 can be charged in advance with electric power from an external power supply before the start of traveling. Therefore, from the viewpoint of improving the energy efficiency during travel, it is desirable to travel by driving the electric motor 14 with the electric power from the battery 30 while stopping the internal combustion engine 12 as much as possible. That is, it is desirable to set the engine start threshold value as high as possible and widen the range in which the vehicle travels in the EV travel mode (hereinafter referred to as “EV range”).

  However, when the EV range is widened, the operation opportunity of the internal combustion engine 12 is reduced. For this reason, it is assumed that the fuel in the fuel tank is stored for a long time without being consumed. Here, there are various types of fuel to be supplied depending on the season and region. For example, fuel with a high fuel density (so-called summer fuel) is normally distributed in summer. The summer fuel is refined so that the low-temperature evaporability is low in order to suppress vapor lock and evaporation deterioration in a high-temperature environment. For this reason, when summer fuel is stored until winter, there is a risk that startability deteriorates due to use in an environment where the outside air temperature is low.

  On the other hand, fuel with a low fuel density (so-called winter fuel) is widely distributed in winter. Winter fuel is refined so as to have low temperature evaporability in order to suppress deterioration of startability. For this reason, when the winter fuel is stored until the summer, the problem of vapor lock and the deterioration of the evaporation emission becomes conspicuous due to use in an environment where the outside air temperature is high. That is, if the relationship between the properties of the stored fuel (for example, fuel density) and the outside air environment (for example, outside temperature) becomes inappropriate, there is a concern that the emission characteristics, drivability, etc. may be adversely affected.

  Therefore, in the system of the first embodiment, when the relationship between the fuel density of the stored fuel and the outside air temperature is inappropriate, the stored fuel is consumed quickly. More specifically, the EV range is reduced when the outside air temperature is out of the allowable temperature range corresponding to the fuel density of the fuel. Here, the allowable temperature range means a temperature range that can be combusted without problems when a fuel having a corresponding fuel density is used, and is defined by, for example, a map shown in FIG.

  FIG. 2 is a map that defines the EV range for the fuel density and the outside air temperature of the fuel. In this figure, the threshold outside air temperature T1 is a temperature corresponding to the upper limit value of the allowable temperature range, and is defined such that the lower the fuel density, the lower the threshold value. This is because the lower the fuel density, the higher the content ratio of the low-temperature evaporating component in the fuel, so that an inappropriate temperature range determined from the viewpoint of evaporation is expanded to the low temperature side. The threshold outside air temperature T2 is a temperature corresponding to the lower limit value of the allowable temperature range, and is defined such that the higher the fuel density, the higher the threshold value. This is because the higher the fuel density, the lower the content ratio of the low-temperature evaporating component in the fuel, so that an inappropriate temperature range judged from the viewpoint of startability is expanded to the high temperature side.

  In the map shown in FIG. 2, a region where the outside air temperature is lower than the threshold outside temperature T1 and higher than the threshold outside temperature T2 is a region belonging to the above-described allowable temperature range. In this region, since the relationship between the outside air temperature and the fuel density is appropriate, the operation is performed in the normal EV range, that is, the normal engine start threshold value.

  On the other hand, a region where the outside air temperature is higher than the threshold outside temperature T1 is a region that does not belong to the above-described allowable temperature range. This region corresponds to a case where the relationship between the outside air temperature and the fuel density is inappropriate, for example, a case where winter fuel with a low fuel density is used at a time when the outside air temperature is high. Further, the region where the outside air temperature is lower than the threshold outside temperature T2 is also a region that does not belong to the above-described allowable temperature range. This region corresponds to a case where the relationship between the outside air temperature and the fuel density is inappropriate, for example, a case where summer fuel having a high fuel density is used at a time when the outside air temperature is low.

  In the system of the present embodiment, an area that does not belong to these allowable temperature ranges is set as an EV range reduction area where the EV range is reduced. More specifically, in this EV range reduction range, the engine start threshold value is set to a value lower than that of the normal EV range. As a result, when the required driving force is relatively low, switching from the EV traveling mode to the engine traveling mode is executed. For this reason, since the travel opportunity in the engine travel mode increases, the fuel consumption can be effectively increased. As a result, the fuel can be consumed quickly, so that the relationship between the outside air temperature and the fuel density can be made appropriate by the subsequent refueling of the fuel, and the emission and drivability can be prevented from being adversely affected. it can.

[Specific Processing in First Embodiment]
Next, specific processing of the first embodiment will be described in detail. FIG. 3 is a flowchart of a routine executed by the ECU 50 in the present embodiment in order to realize the above function. In the routine shown in FIG. 3, first, the threshold outside temperatures T1 and T2 corresponding to the fuel density detected by the fuel property sensor 36 are calculated from the map shown in FIG. 2 (step 100).

  Next, it is determined whether or not the outside air temperature T detected by the temperature sensor 34 is larger than the threshold outside air temperature T1 (step 102). As a result, when it is recognized that T> T1 is established, it is determined that the outside air temperature T is too high (outside the allowable range) with respect to the fuel property, the process proceeds to the next step, and the EV range is reduced. (Step 104). Here, specifically, the engine start threshold value is set to a value lower than that of the normal EV range.

  On the other hand, when T> T1 is not established in step 102, the process proceeds to the next step, and it is determined whether or not the outside air temperature T is lower than the threshold outside air temperature T2 (step 106). As a result, if it is recognized that T <T2 is established, it is determined that the outside air temperature T is too low (outside the allowable range) with respect to the fuel property, the process proceeds to step 104, and the EV range is reduced. .

  On the other hand, if the establishment of T <T2 is not recognized in step 106, it is determined that the outside air temperature T is within the appropriate range (within the allowable range) for the fuel property, and the process proceeds to the next step. The normal EV range is controlled.

  As described above, according to the system of the first embodiment, when the relationship between the outside air temperature T and the fuel density is inappropriate, the EV range is reduced and the fuel consumption is increased. Thereby, since the fuel currently stored can be consumed quickly, the original emission characteristic and drivability can be exhibited by subsequent appropriate fuel supply.

  By the way, although the hybrid vehicle 10 of the system of the first embodiment is configured as a so-called plug-in type hybrid vehicle, it may be configured as a normal hybrid vehicle that does not have a charging function from an external power source.

  In the system of the first embodiment, the EV range is reduced as a configuration for increasing the fuel consumption. For example, in the engine running mode, the output of the internal combustion engine 12 to the electric motor 14 is provided. The ratio may be increased.

  In the system of the first embodiment, the detected value of the temperature sensor 34 is used as the outside air temperature T. However, in the system including the intake air temperature sensor, the detected intake air temperature may be used as the outside air temperature T. Good.

  In the system according to the first embodiment, the switching between the EV driving mode and the engine driving mode is controlled by comparing the required driving force and the engine start threshold value. These switching operations may be controlled based on the load and rotation speed required for the vehicle. More specifically, for example, a predetermined low-load low-rotation region may be defined as a region where the EV traveling mode is performed, and a region where the high-load high-speed rotation is performed may be defined as a region where the engine traveling mode is performed. Good. In this case, when the EV range is reduced more than the normal EV range, the predetermined low-load low-rotation region in which the EV traveling mode is performed may be further reduced in the direction of low-load low-rotation. Thereby, since the area | region where engine driving mode is performed is expanded effectively, fuel consumption can be increased.

  In the first embodiment described above, the fuel property sensor 36 corresponds to the “fuel property detection means” in the first invention, and the temperature sensor 34 corresponds to the “outside air temperature detection means” in the first invention. is doing. Further, when the ECU 50 executes the process of step 100, the “setting means” in the first invention executes the process of step 104, and the “fuel consumption increasing means” in the first invention results. Are realized.

  In the first embodiment described above, the power distribution and integration mechanism 18 is set to the “switching means” in the second invention, and the EV driving mode is set to the “electric driving mode” in the second invention. Low-rotation areas correspond to the “predetermined areas” in the second aspect of the invention. Further, the “fuel consumption increasing means” in the second aspect of the present invention is realized by the ECU 50 executing the processing of step 104 described above.

  Further, in the first embodiment described above, the power distribution and integration mechanism 18 is set to the “switching means” in the third invention, the EV drive mode is set to the “electric drive mode” in the third invention, and the engine start threshold value is set. This corresponds to the “threshold value” in the third aspect of the invention. Further, the “fuel consumption increasing means” according to the third aspect of the present invention is implemented when the ECU 50 executes the process of step 104 described above.

  In the first embodiment described above, the threshold outside temperature T1 is the “upper limit value of the allowable temperature range” in the third aspect of the invention, and the threshold outside temperature T2 is the “lower limit value of the allowable temperature range in the fourth aspect of the invention. Respectively.

DESCRIPTION OF SYMBOLS 10 Hybrid vehicle 12 Internal combustion engine 14 Electric motor 16 Generator 18 Power distribution integration mechanism 20 Reducer 22 Drive wheel 24 Drive shaft 26 Inverter 28 Converter 30 Battery 32 Charging circuit 34 Temperature sensor 36 Fuel property sensor 50 ECU (Electronic Control Unit)

Claims (5)

A control device for a hybrid vehicle comprising an internal combustion engine and an electric motor as power sources,
A fuel tank for storing fuel supplied to the internal combustion engine;
Fuel property detecting means for detecting the fuel density of the stored fuel stored in the fuel tank;
Setting means for setting an allowable temperature range of the outside air temperature suitable for operation of the internal combustion engine based on the fuel density;
Outside temperature detecting means for detecting outside temperature;
Fuel consumption increasing means for increasing the amount of fuel consumed in the internal combustion engine when the outside air temperature does not belong to the allowable temperature range;
A control apparatus for a hybrid vehicle, comprising: It is possible to switch between an electric travel mode in which driving power is output from the electric motor when the operation of the internal combustion engine is stopped and an engine travel mode in which part or all of the driving power is output from the internal combustion engine. Switching means,
The vehicle travels in the electric travel mode until the required load and the required rotational speed required for traveling exceed a predetermined region on the low load and low rotational side, and when the required load and the required rotational frequency exceed the predetermined region. Further comprises traveling mode control means for traveling in the engine traveling mode,
2. The control apparatus for a hybrid vehicle according to claim 1, wherein the fuel consumption increase means reduces the predetermined region when the outside air temperature does not belong to the outside air temperature range as compared with a case where it belongs. It is possible to switch between an electric travel mode in which driving power is output from the electric motor when the operation of the internal combustion engine is stopped and an engine travel mode in which part or all of the driving power is output from the internal combustion engine. Switching means,
Travel mode control means that travels in the electric travel mode until the required drive force required for travel exceeds a predetermined threshold, and travels in the engine travel mode when the required drive force exceeds the threshold. And further comprising
2. The control of a hybrid vehicle according to claim 1, wherein the fuel consumption increasing means sets the threshold value to a lower value when the outside air temperature does not belong to the outside air temperature range than when it belongs. apparatus.   4. The hybrid vehicle control device according to claim 1, wherein the setting unit sets the upper limit value of the allowable temperature range to be lower as the fuel density is lower. 5.   5. The hybrid vehicle control device according to claim 1, wherein the setting unit sets a lower limit value of the allowable temperature range higher as the fuel density is higher.

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