JP3211595B2 - Hybrid electric vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle equipped with a generator driven by an engine and driving a motor by at least one of the power generated by the generator and the power stored in a mounted battery. In particular, the present invention relates to power generation control based on the coolant temperature of the engine.

[0002]

2. Description of the Related Art In recent years, attention has been paid to an electric vehicle which does not emit exhaust gas in consideration of environmental problems. However, the performance of a battery mounted on the vehicle is not sufficient, and a sufficient maximum speed and cruising range can be obtained. Not. To compensate for this problem, a generator driven by the engine is mounted on the vehicle, and the motor is driven by driving the motor with at least one of the power generated by the generator and the power stored in the battery mounted on the vehicle. Hybrid electric vehicles are being developed. The engine mounted on this hybrid electric vehicle is
Since it is operated under relatively limited conditions, it is easy to take measures to purify exhaust gas, and compared to conventional vehicles that run directly with the output of the engine, such as nitrogen oxides, carbon monoxide and hydrocarbons. Emissions can be significantly reduced.

In such a hybrid electric vehicle, the amount of power generated by the generator is determined in consideration of the state of charge (SOC) of a vehicle-mounted battery in addition to the power consumed by the traveling motor. Therefore, even when the electric power consumed by the traveling motor during stop or low-speed traveling is small, if the SOC is small, the engine is operated in a high output state. In such a case, cooling of the engine and the engine cooling water by the traveling wind could not be expected, and there was a case where overheating occurred.

In order to solve the problem of overheating, in a hybrid electric vehicle described in Japanese Patent Application Laid-Open No. 6-48189, the engine is controlled to be idling when the cooling water temperature exceeds 95 ° C., and the water temperature is further reduced. A technique for stopping the engine when the temperature reaches 110 ° C. or higher is disclosed.

[0005] In the cold start of the hybrid electric vehicle, if the temperature of the catalyst for purifying the exhaust gas is not sufficiently high, the harmful components in the exhaust gas may not be sufficiently removed. In order to solve this problem, Japanese Patent Laid-Open No. 5-3 is disclosed.
In the hybrid electric vehicle described in Japanese Patent No. 28528, a technique is disclosed in which the engine is operated near the maximum output when the engine is cold and the warm-up operation is terminated early.

[0006]

However, in the hybrid electric vehicle described in Japanese Patent Application Laid-Open No. 6-48189, idling is controlled when overheating occurs, so that the fuel consumption rate deteriorates. There was a problem. In addition, when the engine is completely overheated, the engine is stopped. Therefore, there is a problem that harmful components contained in the exhaust gas increase upon restarting after the overheating is eliminated.

In the hybrid electric vehicle described in Japanese Patent Application Laid-Open No. 5-328528, when the warming-up is completed, the engine speed suddenly drops to suppress the engine output, or the outside air temperature is low. In some cases, for example, when it is determined that the temperature of the catalyst has dropped, there is a problem that the engine speed suddenly rises and the passenger gets an unnatural impression. Further, when the battery is sufficiently charged, if the power generation output is increased for warming up, the battery may be overcharged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. By adding a cooling water temperature to a control factor, overheating and overcooling of an onboard engine and overcharging of an onboard battery can be prevented. An object of the present invention is to provide a hybrid electric vehicle that does not give an unnatural impression to passengers and the like.

[0009]

In order to achieve the above-mentioned object, a hybrid electric vehicle according to the present invention has a target of a generator based on a power consumption of a traveling motor for driving the vehicle and a charged state of a battery. A hybrid electric vehicle including a generator control device that calculates a power generation amount and controls the generator and an engine that drives the generator based on the target power generation amount, including a water temperature sensor that detects a cooling water temperature of the engine. The generator control device may be configured such that the cooling water temperature is equal to or higher than a normal range upper limit and higher than the normal range upper limit.
When the temperature is equal to or lower than the predetermined temperature, the storage unit that stores the upper limit power generation amount of the generator, which decreases as the cooling water temperature increases, compares the target power generation amount with the upper limit power generation amount, and determines a lower power generation amount as a new one. A target power generation amount recalculation unit that calculates the target power generation amount.

[0010]

Still another hybrid electric vehicle according to the present invention calculates a target power generation amount of a generator based on the power consumption of a traveling motor driving the vehicle and the state of charge of a battery. A hybrid electric vehicle including a generator control device for controlling the generator and an engine that drives the generator based on the water temperature sensor for detecting a cooling water temperature of the engine, wherein the generator control device includes: Cooling water temperature is below the normal range lower limit and
When the temperature is equal to or higher than the predetermined temperature lower than the normal range lower limit value, the storage unit that stores the lower limit power generation amount of the generator, which increases as the cooling water temperature decreases, compares the target power generation amount and the lower limit power generation amount, and And a target power generation amount recalculation unit that calculates the power generation amount of the target as a new target power generation amount.

[0012]

Still another hybrid electric vehicle according to the present invention calculates a target power generation amount of a generator based on the power consumption of a traveling motor for driving the vehicle and the state of charge of a battery. A hybrid electric vehicle including a generator control device for controlling the generator and an engine that drives the generator based on the water temperature sensor for detecting a cooling water temperature of the engine, wherein the generator control device includes: The first operation mode in which the throttle valve is fully opened when the engine speed is equal to or higher than a predetermined speed, and the engine output is adjusted by the throttle valve when the engine speed is lower than the predetermined speed. A mode storage unit for storing a control content of a second operation mode in which the cooling water temperature is adjusted; When the temperature is lower than the water temperature, the first mode is selected. When the cooling water temperature is equal to or higher than the first predetermined water temperature, a target power generation is performed according to the mode selection unit that selects the second mode. And a target power generation amount calculation unit for calculating the amount of power generation.

Further, in a hybrid electric vehicle which selectively controls a generator according to the two operation modes, a timer for measuring an elapsed time after the cooling water temperature exceeds the first predetermined water temperature, and the timer The power generation stop instruction unit may be configured to stop the power generation when the time measured by exceeds a predetermined time.

Further, in the hybrid electric vehicle in which the generator is selectively controlled by the two operation modes, when the cooling water temperature once becomes equal to or higher than a second predetermined water temperature exceeding the first predetermined water temperature, A power generation stop instruction unit for stopping power generation until the cooling water temperature becomes equal to or lower than the first predetermined water temperature may be provided.

[0016]

[0017]

According to the present invention, the cooling water temperature is equal to or higher than the upper limit of the normal range and is higher than the upper limit of the normal range.
In the case where the control is performed based on the lower power generation amount between the upper limit power generation amount and the target power generation amount, which decrease as the cooling water temperature rises, when the temperature of the cooling water temperature is lower than the predetermined temperature , the output is started when the sign of overheating starts to appear. And overheating can be prevented beforehand. As a result, the frequency of occurrence of idling or stopping the engine can be reduced, thereby reducing harmful components in the exhaust gas.

[0018]

Further, the cooling water temperature is lower than the lower limit of the normal range and
When the temperature is equal to or lower than a predetermined temperature lower than the normal range lower limit value, the lower limit power generation amount that increases as the cooling water temperature decreases and the target power generation amount are compared, and when control is performed based on the higher power generation amount, the warm air As the water temperature gradually rises during operation, the amount of power generation can be gradually reduced. This reduces the unnatural impression on passengers as the engine speed drops suddenly during warm-up operation or when the outside air temperature is extremely low, the engine cools down and the engine speed rises suddenly. can do. Also, when the SOC is close to full charge, overcharge due to high-power operation for warm air can be reduced.

[0020]

Further, by selecting the two operation modes based on the cooling water temperature, when the cooling water temperature becomes equal to or higher than the first predetermined water temperature, heat generation of the engine can be suppressed and overheating can be prevented.

Further, in the case where the above-mentioned two operation modes are selectively used, when the cooling water temperature does not drop even after the operation in the low heat generation operation mode for a predetermined time, power generation is stopped to prevent overheating. Can be.

Further, when the above two operation modes are selectively used, when the cooling water temperature becomes equal to or higher than a second predetermined water temperature, the power generation is stopped until the first cooling water temperature is reached. Thus, the overheating state can be eliminated and the engine can be sufficiently cooled.

[0024]

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a hybrid electric vehicle. The generator 10 is driven by the engine 10, and the generated power drives the motor 16 via the inverter 14. Also, the generator 1
When the electric power generated by the motor 2 is smaller than the electric power consumed by the motor 16, the electric power stored in the battery 18 is added to drive the motor 16. The rotation of the motor 16 is transmitted to the wheels 22 via the speed reducer 20 to drive the vehicle. When a braking force is applied to the vehicle, the inverter 14 is controlled so that the motor 16 acts as a generator, and the generated power is charged into the battery 18 in addition to a mechanical brake by friction. Regenerative braking is performed.

The control of these devices is performed by each electronic control unit (hereinafter, referred to as ECU) shown in the figure. EV-ECU24
Is based on the operation amount of an accelerator pedal or a brake pedal (not shown), the rotation speed of the motor 16, and the like.
4 to operate the motor 16 at a desired rotation speed and a desired torque. The generator ECU 26 controls the generator 12 and the engine 10 so as to generate electric power basically corresponding to the electric power consumed by the motor 16. That is, the target rotation speed of the engine 10 when the throttle valve is fully opened is calculated based on a predetermined map from the power consumption of the motor 16, and the field corresponding to the torque generated by the engine at this rotation speed is determined. Is generated in the generator 12 to obtain a desired power generation amount. The battery ECU 2
When it is determined that the storage amount (SOC) of the battery 18 is small by the power generation unit 8, the generator ECU 26 sets the generator 12 to generate more power than the power consumed by the motor 16.
The engine 18 is controlled to charge the battery 18. Although the output control of the engine 10 is basically performed only by the rotation speed as described above, when the engine rotation speed cannot cope with the case where the electric power consumed by the motor 16 or the like is very small, the throttle valve 30 is used. , The output is adjusted.

Further, in this embodiment, the coolant temperature of the engine is detected by the coolant temperature sensor 32, and the power generation amount is controlled based on the coolant temperature. Hereinafter, this will be described.

FIG. 2 shows a map showing the relationship between the cooling water temperature of the engine 10 of this embodiment and the control range of the generator output. This map is stored in a storage unit included in the generator ECU 26. The generator output can be set in an area surrounded by an output upper limit value P _SUP and an output lower limit value P _INF shown in the drawing. For example, when the cooling water temperature is between temperature T ₂ and the temperature T _3, the generator output 0-2
It can be operated in the range of 0 kW, that is, in the whole area, and is operated at an output determined by the other conditions such as the motor power consumption and the SOC of the battery. This cooling water temperature range (T ₂
ＴT ₃ ) is a normal range, and the vehicle of the present embodiment is designed such that a radiator, a cooling fan and the like are operated so that a cooling water temperature is operated in this range in a normal use. However, when the outside air temperature is extremely high, when a high load is applied during low-speed operation, when the outside air temperature is extremely low, or immediately after starting the engine, the cooling water temperature may not fall within the above range. Assuming such a case, in the present embodiment, the generator output is limited by the cooling water temperature.

For example, if the temperature of the cooling water exceeds the temperature T ₃ , it is determined that overheating has occurred, and operation at high output is restricted. Specifically, even when the power consumption of the motor power output increase is determined to be required 20 kW, the cooling water temperature exceeds the temperature T _3, the target power generation amount of the generator ECU26 recalculator Suppresses the generator output to the output upper limit value P _SUP and suppresses a further rise in the cooling water temperature. In order to effectively suppress this rise in water temperature and obtain an output as close as possible to the desired generator output, the output upper limit P
_SUP has become a downward-sloping between the temperature T ₃ and the temperature T _4. In this way, when the sign of overheating starts to appear, the output is not limited so much, and it is assured that the desired generator output is generated as much as possible. If the water temperature continues to rise, control of the output is strengthened, and control is given with emphasis on preventing overheating. Finally, if the cooling water temperature becomes a temperature T _4, as the target power generation amount recalculation unit overheat occurs, the generator output 0kW
The engine also runs at idling.

On the other hand, when the cooling water temperature is low, the output lower limit value P
_INF is set. This is because, for example, during a cold start, the temperature of the exhaust gas purifying catalyst is quickly increased to a temperature at which the catalyst acts by maintaining a high calorific value of the engine. Therefore, even when the motor power consumption is small and the SOC is sufficient, the target power generation amount recalculation unit increases the generator output, increases the heat generation amount, and ends the warm-up operation early. Further, between the cooling water temperature is temperature T ₂ from the temperature T _1, the output lower limit value P
_INF is falling to the right. By setting in this way, it is possible to prevent the engine speed from suddenly dropping when the cooling water temperature reaches the normal temperature, thereby preventing the passenger from giving an unnatural impression. That is, even if the target power generation amount determined from other conditions the following output lower limit value P _INF, the generator output is set to the lower limit value P _INF, gradually decreases it is the lower limit value P _INF with increasing temperature of the cooling water As a result, the engine speed gradually decreases.

When the outside air temperature is very low and the cooling water temperature gradually decreases from the normal range (overcooled state), the power generation is increased when the overcooling sign appears as in the case of the overheating. As a result, the calorific value of the engine is raised to prevent the cooling water temperature from lowering.

In the case of the present embodiment, the output of the generator starts to decrease when the temperature of the cooling water rises to some extent.
Accordingly, the electric power charged in the battery 18 decreases. Thus, it is possible to suppress the battery 18 from being overcharged. That is, when the generator 12 and the engine 10 are operated at a high output for the warm-up operation, the surplus electric power is used for charging the battery. At this time, if the SOC is in a sufficient state, the battery is overcharged.
In the case of this embodiment, as described above, the generator output gradually decreases, and thus the charging current gradually decreases to reduce the possibility of overcharging.

FIG. 3 is a flowchart showing a control flow of the present embodiment. Initialization processing (S100)
Is performed and the engine is started (S102), it is determined whether the vehicle is stopped (S104). If the vehicle is stopped, the target rotational speed N _E of the engine is set to the rotational speed N _Emin idling (S106). On the other hand, when the vehicle is not stopped, the target engine speed N based on the power and the SOC consumed by the motor 16 is set.
_E is calculated (S108). A power to be power sum of power to be charged in the power and battery 18 by the motor 16 is consumed, the relationship of the power to be the power and the engine speed N _E is predetermined. At this time, the battery 1
When discharging from 8, it is treated as negative power consumption,
Calculating the target engine rotational speed N _E is performed.

[0034] When the target engine speed N _E is determined,
4 than to calculate a target power generation amount P _GEN corresponding to the rotational speed N _E (S110). Further, an upper limit value P _SUP and a lower limit value P _{INF of} power generation are calculated based on the cooling water temperature of the engine at this time based on FIG. 2 (S112). Then, the calculated target power generation amount P _GEN is compared with the lower limit value P _INF (S11).
4), when the target power generation amount P _GEN falls below the lower limit value P _INF , it is further determined whether the SOC is equal to or more than the upper limit value (S11).
6). The upper limit value of the SOC is set to a value higher than the upper limit of the range of the ordinary SOC, and if it exceeds this value, the life of the battery 18 is greatly affected. In the case of the present embodiment, the normal SOC range is set slightly lower with a margin in consideration of electric power regenerated from the motor to the battery during regenerative braking. Therefore, even if the regenerative electric power or the warm-up operation exceeds the normal SOC range, the battery 18 does not deteriorate much in a short time. If the SOC is equal to or more than the upper limit in step S116,
The target power generation amount P _GEN has already been calculated as 0 in steps S108 and S110, and the engine 10 and the generator 12 are controlled with the values as they are.

In step S116, the SOC
Is not greater than or equal to the upper limit, the target power generation amount P
The _GEN was reconfigured as a lower limit value P _INF, it controls the engine 10 and the generator 12.

On the other hand, at step S114, the target power generation amount P
If _{the GEN} is determined to not lower than the lower limit value P _INF, the target power generation amount P _GEN and the upper limit value P _SUP are compared (S
120). When the target power generation quantity P _GEN exceeds the upper limit value P _SUP, the target power generation amount P _{GE N} is reset to the upper limit value P _SUP (S122). Also, when the target power generation amount P _GEN does not exceed the upper limit value P _SUP, the target power generation amount P _GEN calculated in S110 is maintained. Then, the slot valve opening θ _TH is calculated based on the target power generation amount P _GEN and the target engine speed set in the above steps (S1).
24) Also, the field current is calculated (S126). In this embodiment, the control of the throttle valve opening θ _TH
This is performed when the target generator output becomes 6 kW or less. In the case of an output higher than this, the throttle valve having a good fuel consumption rate is operated in a fully opened state (WOT), and the output control is performed based on the engine speed. The reason why the output control by the throttle valve at the output of 6 kW or less is that when the engine speed is low, the vibration level increases to give an unpleasant impression to the occupant or the engine combustion becomes unstable and the exhaust gas becomes unstable. This is because harmful components in the composition may increase.

As long as the start key is on (S1
30) Returning to step S104, the above control flow is repeated. When the start key is turned off, an end process (S132) is executed.

[0038] According to the above control flow, since it is operated in the range shown in FIG. 2, to prevent overheating and over-cool in advance, conventional range, that is, the cooling water temperature is operated at between a temperature T ₂ of the temperature T ₃ Ratio increases. Further, even if it deviates from the normal range, since the control amount is changed according to the degree of departure, it is possible to prevent the engine speed from suddenly changing and giving the passenger an unnatural feeling.

FIGS. 5 to 7 show control flowcharts of the apparatus according to another embodiment of the present invention. The configuration of the electric vehicle according to the present embodiment basically has the configuration illustrated in FIG. 1, and the feature of the present embodiment is that two types of relationships between the target engine speed and the target generator output are determined. That is. That is, as shown in FIG. 8, in the diagram corresponding to FIG. 4 described above, the target generator output for a certain target engine speed takes two values, and these values are used properly according to the situation. One of these values is the high output mode M ₁ corresponding to FIG. 4, and the other is the low output mode M ₂ .
In high power mode M _1, the target engine speed is 1
From 200 rpm to 2800 rpm, the target output (6 to 20 k
W) is achieved, and outputs below this range are accommodated by adjusting the opening of the throttle valve. On the other hand, in the low output mode M _2, it has been adjusted to the output by the engine speed and the throttle valve opening across the high output even with the same engine speed mode M ₁
Low output is obtained.

Next, the control flow of this embodiment will be described.
In the control flows of FIGS. 5 to 7, the same steps as those in the control flow of the above-described embodiment shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

[0041] Step S106 and the target engine speed N _E at S108 is calculated, the cooling water temperature T is compared with a predetermined temperature T ₂ (S200), the predetermined temperature T ₂
If more is compared further with the predetermined temperature T ₃ (S2
01). If the coolant temperature is temperature T ₂ or T ₃ or less is a normal operation region, a flag indicating this (status)
H0 is erected (S202), control is performed according to the high power mode M ₁ similarly to the embodiment described above (S203).

Further, the cooling water temperature T in step S201 exceeds the temperature T _3, if it is further temperature T ₄ less that (S204), as there are signs of overheating, according to this Control is performed. First, it is determined whether the flag (status) indicating the degree of overheating is H2 (S205). This flag is H1 when the sign of overheating starts, and becomes H2 when the overheating has been completed or the cooling water temperature has not been completely overheated but has been kept high for a predetermined time. In step S205, the flag is determined not to be H2, a condition of overheating before flag (status) and H1 (S206), the target power generator output P _GEN based on low-power mode M ₂ is calculated (S207). Further, it is determined whether the elapsed time from when the flag becomes H1 exceeds a predetermined value (S20).
8) The flag is set to H2 only when exceeding.
In such a case, there is no complete overheating,
This indicates that the cooling water temperature has continued to be slightly higher than the normal operation range, and the cooling method at this time cannot return the cooling water temperature to the normal operation range or it takes a long time to return it. This is the case.

On the other hand, when the cooling water temperature T in step S204 is whether or exceeds the temperature T _4, or a flag at step S205 has a H2, a flag is set to H2 (S210), the target power generator output P the _GEN and target engine rotational speed N _E as 0 (S211, S212), the control of subsequent performed.

Then, steps S208, S209, S
The process proceeds from step 212 to step S124, and the same control as in the above-described embodiment is performed thereafter.

In the control for suppressing the overheating, when the coolant temperature is increasing, the flag is sequentially changed from H0 to H1, H2. Therefore, when the cooling water temperature slightly deviates from the normal operation range and the sign of overheating starts to appear, the output of the engine, that is, the calorific value is suppressed by the low output mode, and the sign of overheating is prevented from further developing. If the cooling water temperature does not return to the normal range even after the lapse of a predetermined time despite the low output, the engine output is controlled to 0, that is, the idling state, to cool the engine. Further, when the cooling water temperature exceeds the temperature T ₄ is completely is determined that becomes overheated conditions to control the engine idling.

When the cooling temperature falls, if the flag is once set to H2, the idling control is continued until the cooling water temperature falls within the normal range. As a result, the engine is controlled so that the output of the engine is generated after the engine is sufficiently cooled. By this control, the idling state and the low output state (state at the time of the flag H1)
Hunting can occur between the two to prevent an unnatural impression on the passenger.

Next, a case where the cooling water temperature is still low immediately after the start of the engine and a case where the cooling water temperature is lowered due to overcooling will be described. When the cooling water temperature T in step S200 is lower than the temperature T _2, are further compared temperatures T ₁ and lower than the temperature T ₂ (S213). Further, the cooling water temperature T is either a predetermined time from when less than temperature T ₂ has elapsed beyond the temperature T ₁ (S21
4). If the predetermined time has not elapsed, the target generator output P _GEN is calculated from the cooling water temperature T based on the graph shown in FIG. The target generator output P _GEN has a higher value as the cooling water temperature is lower, and is set so that the calorific value of the engine is larger as the cooling water temperature is lower. Therefore, for example, when a sign of overcooling appears, it is possible to prevent the engine speed from suddenly increasing and giving an unnatural impression to the occupant. When the temperature of the cooling water is very low, the calorific value of the engine 10 is sufficiently increased,
The engine can be brought into a normal operation state at an early stage, and the catalyst temperature rises at an early stage, so that harmful components in the exhaust gas can be efficiently treated.

On the other hand, if it is determined in step S 213 that the cooling water temperature T has not reached the temperature T ₁ , or if a predetermined time has elapsed since the cooling water temperature T has exceeded the temperature T ₁ and has become less than T ₂ , Steps S216, S217, S21
At 8, the engine speed, the target power generation amount _PGEN, and the throttle valve opening are set to the maximum values. In the case of this embodiment, the engine speed is 2800 rpm, the target power generation amount is 20 kW,
The throttle valve opening is set to full open.

As described above, in the present embodiment, when the cooling water temperature T is extremely low, the control is performed such that the calorific value of the engine 10 is maximized, and the control is promptly shifted to the normal operation range. Further, when the temperature is slightly low, the engine is controlled to generate an engine heat value corresponding to the cooling water temperature T, thereby preventing a sudden change in the engine speed. In calculating the target power generation amount on the low temperature side, the target power generation amount is calculated independently of the current power storage amount (SOC) of the battery 18,
Therefore, even when the SOC is close to 100%, power generation is performed at the maximum power generation amount, and the battery may be overcharged. However, in the present embodiment, since the power generation amount gradually decreases from the time of exceeding the temperature T _1, it is possible to reduce the case where the overcharge.

FIGS. 10 and 11 show still another embodiment according to the present invention. The configuration of the electric vehicle according to the present embodiment basically has the configuration shown in FIG. 1, and the characteristic feature of the present embodiment is that when an overheating sign appears, the upper limit value P _SUP of the generator output is set. If the overheating sign is not eliminated even if the _{fixed amount} is reduced, the upper limit P _SUP is further reduced, and this is repeated. Then, the lower of the generator target output P _GEN and the upper limit P _SUP is newly determined as the generator target output P _GEN . As a result, when the sign of overheating appears, the target output P _GEN is gradually corrected to a smaller value.

[0051] Further, when the signs of over-cool has appeared, the lower limit value P _INF of the generator output is raised a predetermined amount, still if signs of over-cool persists, to further increase the lower limit value P _INF, repeating this Things.
Then, defining the higher and the generator target output P _{GE N} of the lower limit value P _INF as a new target generator output P _GEN. As a result, when the sign of overcooling appears, the target output _PGEN is gradually corrected to a larger value.

In the flowcharts shown in FIGS. 10 and 11, the control flowchart of each of the above-described embodiments is shown in FIG.
Steps similar to those in FIGS. 5, 6, and 7 are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, when it is determined in step S104 that the vehicle is running, a target generator output P _GEN is first calculated based on the output value of the motor 16 and the SOC of the battery 18 (S300). ). On the other hand, when the vehicle is stopped, the target generator output _PGEN is set to 0.

When the cooling water temperature T is in the normal operation range (T ₂ ≦ T ≦ T
_In the case of ₃ ), the upper limit value P _SUP of the generator output is set to the maximum output value P _MAX of the generator (S302). Accordingly, the step S114 and subsequent steps, the control of the generator 12 and the engine 10 is performed on the basis of the target generator output P _GEN set in step S300. In addition, when signs of overheating appear (T ₃ <T ≦ T
₄ ) The upper limit P _SUP of the generator output is reduced by a predetermined amount ΔP ₁ (S301). Therefore, step S120
Through the processing of S122 and S122, the lower of the upper limit value P _SUP and the target generator output P _GEN calculated in step S300 is set as a new target generator output. If the cooling water temperature does not decrease even in this state, the upper limit value P _SUP is further reduced by a predetermined amount ΔP ₁ . And this is repeated. As a result, when the sign of overheating appears, the target output P _GEN calculated in step S300 is corrected to a lower value.

Further, when the overheating proceeds (T ₄ <
T), the upper limit value P _{SUP is set} to 0 (S303), and heat generation is minimized to eliminate overheating. As in the embodiment shown in FIG. 5 and the like, in this embodiment, once the overheating state (T ₄ <T) is reached, the power generation is continued until the cooling water temperature returns to the normal operation range (T ₂ ≦ T ≦ T ₃ ). The engine output becomes 0, and the engine is also controlled to the idling state.

In this way, the amount of heat generated by the engine can be reduced when the overheating symptom appears, thereby suppressing overheating. At this time,
Since the target power generation amount P _GEN can be reduced to 0, the calorific value of the engine can be reduced at an early stage. Further, when the overheating is completely caused, the generator output is immediately set to 0, and the calorific value of the engine can be minimized. Further, when the sign of overheating appears, the output of the generator does not increase until the cooling water temperature falls within the normal operation range, so that the cooling water can be reliably cooled. Further, when the overheating is completely over, the output of the power generation model is set to 0 until the cooling water temperature decreases to the normal operation range, so that the cooling water can be reliably cooled.

On the other hand, if the sign of overcooling appears (T ₁ ≦ T <T ₂ ), the lower limit value P _INF of the generator output is increased by a predetermined amount ΔP ₂ (S304). If the cooling water temperature does not recover even in this way, the lower limit value P _INF is further reduced by Δ
P _{2 is} increased and this is repeated. If the cooling water temperature is still lower (T <T ₁ ), such as immediately after the start of the engine, the generator output is set to the maximum value (S305), and control is performed to complete the warm-up of the engine early.

As described above, when the sign of overcooling appears, the engine is controlled so that the calorific value of the engine increases, so that the overcooling can be suppressed. Further, at this time, the target power generation amount can be increased to the maximum value, so that the cooling water temperature can be quickly restored to the normal operation range. Further, when the cooling water temperature is extremely low, for example, immediately after the start of the engine, the warming-up operation can be terminated early by maximizing the calorific value of the engine. Further, once the sign of overcooling appears, the generator output is not corrected downward until the coolant temperature falls within the normal operation range, so that the coolant can be reliably warmed. Further, once completely overcooled, the generator output maintains the maximum value until the normal operation range is reached, so that the warm-up operation can be terminated early.

[0059]

As is evident from the foregoing description, according to the present invention, the cooling water temperature is higher than the conventional range upper limit value or more and the customary range upper limit
If the control is performed based on the lower power generation of the upper limit power generation amount and the target power generation amount that decrease as the cooling water temperature rises when the temperature of the cooling water rises below And overheating can be prevented beforehand. As a result, the frequency of occurrence of idling or stopping the engine can be reduced, thereby reducing harmful components in the exhaust gas.

[0060]

Further, the cooling water temperature is lower than the lower limit of the normal range and
When the temperature is equal to or higher than the predetermined temperature lower than the normal range lower limit value, the lower limit power generation amount that increases as the cooling water temperature decreases and the target power generation amount are compared, and when the control is performed based on the higher power generation amount, the warm air As the water temperature gradually rises during operation, the amount of power generation can be gradually reduced. This reduces the unnatural impression on passengers as the engine speed drops suddenly during warm-up operation or when the outside air temperature is extremely low, the engine cools down and the engine speed rises suddenly. can do. Also, when the SOC is close to full charge, overcharge due to high-power operation for warm air can be reduced.

[0062]

When the two operation modes are selected based on the cooling water temperature, when the cooling water temperature becomes equal to or higher than the first predetermined water temperature, the heat generation of the engine can be suppressed and overheating can be prevented.

Further, in the case where the above two operation modes are selectively used, when the cooling water temperature does not drop even after the operation in the low heat generation operation mode for a predetermined time, power generation is stopped to prevent overheating. Can be.

Further, when the above two operation modes are selectively used, when the cooling water temperature becomes equal to or higher than the second predetermined water temperature, the power generation is stopped until the first cooling water temperature is reached. Thus, the overheating state can be eliminated and the engine can be sufficiently cooled.

In a predetermined range in which the cooling water temperature is determined to be in the cold state, when the control is performed based on the target power generation amount in the cold state which is determined only by the cooling water temperature, other factors cause the engine to operate. It is possible to prevent a sudden change in the number of revolutions from giving an unnatural impression to the passenger.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a hybrid electric vehicle according to the present invention.

FIG. 2 is a diagram showing a relationship between an engine cooling water temperature and a generator output in the hybrid electric vehicle according to the present invention.

FIG. 3 is a flowchart showing a control flow of the embodiment according to the present invention.

FIG. 4 is a chart for calculating a target generator output from a target engine speed in the control flow shown in FIG. 3;

FIG. 5 is a flowchart showing a control flow of another embodiment according to the present invention.

FIG. 6 is a flowchart showing a control flow of another embodiment according to the present invention, and is a flowchart showing a control flow following the flowchart shown in FIG. 5;

FIG. 7 is a flowchart showing a control flow of another embodiment according to the present invention, and is a flowchart showing a control flow following the flowchart shown in FIG. 5;

FIG. 8 is a chart for calculating a target generator output from a target engine speed in the control flows shown in FIGS. 5 to 7;

FIG. 9 is a chart for calculating a target generator output from a target engine speed in the control flows shown in FIGS. 5 to 7;

FIG. 10 is a flowchart showing a control flow of still another embodiment according to the present invention.

FIG. 11 is a flowchart showing a control flow of still another embodiment according to the present invention, and is a flowchart showing a control flow following the flowchart shown in FIG. 10;

[Explanation of symbols]

10 engine, 12 generator, 16 motor, 18
Battery, 26 Generator ECU, 28 Battery EC
U, 30 Throttle valve, 32 Water temperature sensor, P
_GEN target power output, P _SUP power output upper limit, P _INF
Generated output lower limit.

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60L ⁷ /00-13/00 B60K 6/02 F02B 61/00 F02D 29/02

Claims (5)

(57) [Claims] (1) power consumption of a traveling motor for driving a vehicle;
A hybrid electric vehicle including a generator control device that calculates a target power generation amount of the generator based on the storage state of the battery and controls the generator and an engine that drives the generator based on the target power generation amount, A cooling water temperature sensor for detecting a cooling water temperature of the engine, wherein the generator control device decreases as the cooling water temperature increases when the cooling water temperature is equal to or higher than a normal range upper limit value and equal to or lower than a predetermined temperature higher than the normal range upper limit value. A storage unit that stores an upper limit power generation amount of the generator, a target power generation amount recalculation unit that compares the target power generation amount and the upper limit power generation amount, and calculates a lower power generation amount as a new target power generation amount. A hybrid electric vehicle comprising: 2. The power consumption of a traveling motor for driving a vehicle,
A hybrid electric vehicle including a generator control device that calculates a target power generation amount of the generator based on the storage state of the battery and controls the generator and an engine that drives the generator based on the target power generation amount, A cooling water temperature sensor for detecting a cooling water temperature of the engine; wherein the generator control device increases as the cooling water temperature decreases when the cooling water temperature is equal to or lower than a normal range lower limit value and equal to or higher than a predetermined temperature lower than the normal range lower limit value. A storage unit that stores a lower limit power generation amount of the generator, a target power generation amount recalculation unit that compares the target power generation amount and the lower limit power generation amount, and calculates a higher power generation amount as a new target power generation amount. A hybrid electric vehicle comprising: 3. The power consumption of a traveling motor for driving a vehicle,
A hybrid electric vehicle including a generator control device that calculates a target power generation amount of the generator based on the storage state of the battery and controls the generator and an engine that drives the generator based on the target power generation amount, A water temperature sensor for detecting a cooling water temperature of the engine, wherein the generator control device is configured to fully open the throttle valve when the rotation speed of the engine is equal to or higher than a predetermined rotation speed, and to output the engine output by the throttle valve when the rotation speed is lower than the predetermined rotation speed A mode storage unit for storing control contents of a first operation mode in which the adjustment of the cooling water temperature is performed and a second operation mode in which the engine output is adjusted by the throttle valve over the entire operation range; If the temperature is lower than the predetermined water temperature, the first operation mode is selected. If the cooling water temperature is equal to or higher than the first predetermined water temperature, the second operation mode is selected. A hybrid electric vehicle comprising: a mode selection unit that selects a power generation mode; and a target power generation amount calculation unit that calculates a target power generation amount according to the selected operation mode. 4. The hybrid electric vehicle according to claim 3, wherein a timer for measuring an elapsed time after the cooling water temperature exceeds the first predetermined water temperature, and a time measured by the timer exceeds a predetermined time. And a power generation stop instruction unit for stopping power generation. 5. The hybrid electric vehicle according to claim 3, wherein when the cooling water temperature once becomes equal to or higher than a second predetermined water temperature that exceeds the first predetermined water temperature, the cooling water temperature becomes equal to or lower than the first predetermined water temperature. A hybrid electric vehicle comprising a power generation stop instruction unit for stopping power generation until the power generation is stopped.