JP3449143B2 - Generator control device for hybrid electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent overheating even a radiator of the same capacity as that of a vehicle equipped with an internal combustion engine by conducting such control as to generate power at an allowable power generation output when targeted power generation output is allowable power generation output or higher. SOLUTION: An engine generator 1 is constituted of an engine 2 and a generator 3, and a radiator 4 is attached onto the engine 2 to send cooling wind to the radiator 4 by a motor fan 5. An outside air temperature sensor 6 is formed in the vicinity of the radiator 4. An engine controller 7 and a power generation controller 8 control the engine 2 and the generator 3 respectively. The potential amount of radiator heat dissipation is obtained by cooling wind from the motor fan 5 and running wind of a vehicle. The allowable power output of the engine generator 1 is determined according to the potential amount of radiator heat dissipation to control power generation so as to generate power in its range. It is thus possible to prevent overheating even a radiator of the same capacity as that of a vehicle equipped with an internal combustion engine of the same displacement as a conventional one.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a battery and an engine generator as power sources, and when the remaining capacity (charging rate) of the battery decreases, the engine The present invention relates to a generator control device for a hybrid electric vehicle that generates power using a generator. 2. Description of the Related Art An electric vehicle in which a driving wheel is rotated by a motor is known as a low-pollution vehicle with little exhaust gas. However, if only a battery is mounted as a power source for the motor, the vehicle cannot travel a long distance. Thus, there is a so-called hybrid electric vehicle in which an engine generator is mounted as a power source in addition to a battery. In such a hybrid electric vehicle,
In order to prevent exhaust gas from being exhausted as much as possible during driving, the vehicle is driven only by the battery until the remaining battery capacity decreases to a predetermined value. When the value decreases to a predetermined value, the power generation by the engine generator is started, the power is supplied to the motor, and the battery is charged. Further, the power output of the engine generator is converted into a low voltage and supplied to a normal on-vehicle electric load other than the motor. [0004] Since the power generation control of the engine generator is automatically performed by the vehicle controller while monitoring the remaining capacity of the battery, power generation may be performed even while the vehicle is stopped. Incidentally, even when the vehicle is stopped, the same engine output may be required as in a case where the vehicle is traveling at a speed of 60 to 70 km / h in a normal internal combustion engine vehicle having the same displacement. [0005] In such an engine generator of a hybrid electric vehicle, it is necessary to prevent the engine from overheating even when generating power at the maximum output in a hot summer time. A radiator for cooling is attached to the engine to prevent overheating, but in order to prevent overheating even during power generation as described above, the radiator is about twice that of a radiator of an internal combustion engine vehicle with the same displacement. It was necessary to attach a radiator with a volume. However, when a radiator having twice the volume is mounted, a large mounting space is required, and the weight and cost increase. In view of the above, there has been proposed an apparatus in which the radiator is limited to that of a normal internal combustion engine vehicle having the same displacement, and the amount of generated power is controlled so as not to overheat. Such a proposal is disclosed in Japanese Patent Application Laid-Open No. 8-168.
Japanese Patent Application Laid-Open No. 103-103103 discloses a technique in which the temperature of an engine cooling water is detected, and the amount of power generation is suppressed when an overheating sign appears. [0007] In the above-mentioned conventional generator control device for a hybrid electric vehicle, a countermeasure is taken after the sign of overheating appears, so that the engine is eventually deteriorated. However, there is a problem that fuel efficiency and exhaust gas deteriorate. An object of the present invention is to solve the above-described problems by taking measures in advance so that the signs of overheating do not appear, instead of taking measures after the signs of overheating appear. . [0008] In order to solve the above-mentioned problems, according to the present invention, there is provided means for detecting a remaining capacity of a battery for supplying power to a motor for driving a vehicle, and obtaining a target power generation output from the remaining capacity. Means for controlling an engine generator so as to generate the target power generation output, a generator control device for a hybrid electric vehicle, comprising: an outside air temperature sensor, a vehicle speed sensor, a signal from the outside air temperature sensor, and a signal from the vehicle speed sensor. Means for calculating the radiator heat dissipation amount based on the signal of
Means for determining an allowable power output without overheating the engine from the radiator radiable amount, and when the target power output is smaller than the allowable power output,
Control means for controlling the target power generation output to generate power, and when the target power generation output is equal to or higher than the allowable power generation output, controlling to generate the allowable power generation output. [Work] Detecting the outside air temperature and the vehicle speed, and obtaining the heat radiation capability of the radiator attached to the engine generator at that time,
A power generation output (allowable power generation output) that does not cause overheating is obtained based on the heat radiation capability. On the other hand, the power to be generated (target power output) is determined from the remaining capacity of the battery, but the power is always generated within the range of the allowable power output. That is, even when the target power generation output is larger than the allowable power generation output, power is generated only at the allowable power generation output. Therefore, even if the radiator attached to the engine of the hybrid electric vehicle is a radiator having the same performance as that of a normal internal combustion engine vehicle having the same displacement, overheating does not occur. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a generator control device for a hybrid electric vehicle according to the present invention. In FIG.
1 is an engine generator, 2 is an engine, 3 is a generator, 4 is a radiator, 5 is an electric fan, 6 is an outside temperature sensor, 7 is an engine controller, 8 is a power generation controller, 9 is a rectifier, 10 ... current sensors, 11 Is a battery, 12 is an inverter, 13 is a motor, 14 is a differential gear, 15 is a driving wheel, 1
6 is a vehicle speed sensor, 17 is a vehicle controller, 18 is an arithmetic unit, and 19 is a memory. The battery 11 is a high-voltage (for example, 300 V) battery for supplying power to the motor 13 for driving the vehicle. A battery of a voltage (eg, 12 V) is also mounted. If the motor 13 is operated as a generator during vehicle braking, regenerative electric power can be obtained. The engine generator 1 includes an engine 2 and a generator 3. Radiator 4 for engine 2
The cooling air is sent from the electric fan 5 to the radiator 4. An outside air temperature sensor 6 for detecting an outside air temperature is provided near the radiator 4. The outside air temperature detection signal detected by the outside air temperature sensor 6 is sent to the vehicle controller 17. The AC voltage (three phases) generated by the engine generator 1 is rectified by the rectifier 9. Inverter 12
Converts a DC voltage from the battery 11 or the rectifier 9 into an AC voltage (three-phase). The motor 13 is rotated by the AC voltage from the inverter 12, and its rotational force is
Is transmitted to the drive wheels 15. The vehicle speed sensor 16
The rotation speed of the motor 13 is detected, and a detection signal is sent to the vehicle controller 17. The engine controller 7 and the power generation controller 8 control the engine 2 and the generator 3, respectively. The voltage V and the current I (discharge current, charge current) of the battery 11 are detected by the current sensor 10 and the like, and a detection signal is sent to the vehicle controller 17. The vehicle controller 17 determines the amount of discharge or charge in the battery 11 by detecting the voltage V and the current I of the battery 11, and determines the remaining capacity (battery charge rate) of the battery 11 by a known method. For example, a map related to the remaining capacity is stored in the memory 19 in advance, and the map is obtained by referring to the map. The vehicle controller 1
7 also receives vehicle information such as a signal from an accelerator sensor,
The inverter 12 and the motor 1
A control signal is issued for 3 and the like. The memory 19 is for storing control programs and maps required for control, for storing detection signals, and for storing data calculated by the arithmetic unit 18. Examples of the map stored in the memory 19 in the present invention include the maps shown in FIGS. 3 and 4 described later. According to the present invention, the radiator radiable amount is obtained from the cooling wind from the electric fan 5 and the running wind of the vehicle, and the allowable power generation output of the engine generator 1 is determined in accordance with the radiator radiable amount. The power generation is controlled so as to generate power within the vehicle. FIG. 3 is a diagram showing the relationship between the radiator cooling wind speed and the radiator radiable amount. The horizontal axis represents the radiator cooling wind velocity W, and the vertical axis represents the radiator radiable amount Q. Curve b, b, c are curves respectively outside temperature indicates the relationship between the two in the case of _{T 1, T 2, T 3} (T 1 <T 2 <T 3). The cooling air to the radiator is only the air from the electric fan 5 when the vehicle is stopped, and applies the wind according to the running air when the vehicle is running. Accordingly, the radiator cooling wind speed is obtained from the rotation speed of the electric fan 5 when the vehicle is stopped, and if the operation is performed at a constant rotation speed,
The wind speed is also constant. The traveling wind speed increases as the vehicle speed increases. However, since the traveling wind does not directly hit the radiator, the wind speed of the traveling wind does not directly correspond to the wind speed to the radiator. The relationship between the wind speed of the traveling wind and the resulting wind speed to the radiator differs depending on the structure around the radiator, and therefore differs for each type of vehicle. Exactly, it must be determined by experiments or the like. The relationship between the vehicle speed and the wind speed of the radiator cooling air (FIG. 3) when the vehicle stops or runs while the electric fan 5 is rotating may be obtained by experiments and stored in the memory 19 in advance as a map. The wind speed to the radiator can be determined according to the vehicle speed detected by the vehicle speed sensor 16. According to the map of FIG. 3, for example, outside air temperature detected by the outside air temperature sensor 6 is is T _2, when the radiator cooling air velocity was W1, radiator heat dissipation possible amount Q
₁ and is required. FIG. 4 is a diagram showing the relationship between the radiator radiable amount and the allowable power generation output. The horizontal axis represents the radiator heat radiation amount capable Q, and the vertical axis represents the allowable power generation output P _A.
Since the radiator heat dissipation possible amount Q and the allowable power generation output P _A has a functional relationship can be expressed by a function that _{P A = F 2 (Q)} . If the radiator heat dissipation can weight of Q _1, power is allowable power generation output is determined to be P _A1, which, when a radiator heat dissipation can weight of Q _1, which may be power without overheating the engine, P _A1 is shown. A request for a power generation output issued from the vehicle controller 17 to the engine generator 1 (ie,
The target power generation output) differs depending on the value of the remaining capacity of the battery 11, but if the power generation output is smaller than the allowable power generation output, there is no concern about overheating. When the requested power generation output is larger than the allowable power generation output, overheating does not occur as long as power generation is performed only at the allowable power generation output. Next, the power generation control operation of the present invention will be described.
FIG. 2 is a flowchart illustrating a control operation according to the present invention. Step 1: The remaining capacity B of the battery 11 is determined. this is,
It is determined by monitoring the voltage and current (discharge current, charge current) of the battery 11. Step 2 ... determine a target power generation output P _0. This is determined by the remaining battery capacity B. That is, P ₀ = F
_{1 It is} obtained by a function (map) also referred to as (B). Step 3: The outside air temperature T detected by the outside air temperature sensor 6 and the vehicle speed V detected by the vehicle speed sensor 16 are read. Step 4: Calculate the radiator cooling wind speed from the vehicle speed V, etc.
The radiator heat dissipable amount Q is obtained from the map of FIG. Step 5 ... from the map of FIG. 4, obtains the allowable power generation output _{P A (P A = F 2} (Q)). Step 6: It is checked whether or not the target power generation output P ₀ obtained in Step 2 is smaller than the allowable power generation output P _A obtained in Step 5. If it is smaller, even if the engine generator 1 is caused to generate the target power generation output P ₀ ,
There is no worry that the engine will overheat. Therefore, in that case, the process proceeds to the normal power generation control routine of step 9. However, if larger than the allowable power generation output P _A is and can lead to overheating if caused to directly power. Step 7: If the allowable power generation output is larger than P _A , the value of the target power generation output is changed from P ₀ to P _A. That is, in this case, in order to prevent overheating, the power is switched to generate less power than the requested power. Step 8: The power generation of the engine generator 1 is controlled so as to generate the target power generation output determined in the above steps.
Specifically, the power generation control is performed by the engine controller 7 and the power generation controller 8 according to a command from the vehicle controller 17.
Done by As described above, according to the generator control apparatus for a hybrid electric vehicle of the present invention, the power generation output (allowable power generation) that does not cause overheating based on the heat radiation capability of the radiator mounted thereon. Output), and when the target power generation output obtained from the remaining capacity of the battery is larger than the allowable power generation output, the power is generated at the allowable power generation output, so that the following effects are obtained. Even if the radiator attached to the engine of the hybrid electric vehicle is a radiator having the same performance as that of a normal internal combustion engine vehicle having the same displacement, overheating does not occur. Since it is not necessary to increase the capacity of the radiator so that the maximum target power output required from the remaining battery capacity can be generated even in hot summer months, the mounting space is reduced, and the weight and cost can be reduced. Rather than taking measures after the sign of overheating, the power generation is suppressed before the state is reached. Therefore, the engine does not deteriorate due to overheating, and the fuel consumption and exhaust gas do not deteriorate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a generator control device for a hybrid electric vehicle according to the present invention; FIG. 2 is a flowchart illustrating a control operation in the present invention; FIG. 3 is a radiator cooling wind speed and a radiator radiable amount; FIG. 4 is a diagram showing a relationship between a radiator radiable amount and an allowable power generation output. [Description of References] 1 ... Engine generator, 2 ... Engine, 3 ... Generator, 4 ...
Radiator, 5 ... Electric fan, 6 ... Outside temperature sensor, 7 ...
Engine controller, 8: Power generation controller, 9: Rectifier, 10: Current sensor, 11: Battery, 12: Inverter, 13: Motor, 14: Differential gear, 15: Drive wheel, 1
7 vehicle controller, 18 arithmetic unit, 19 memory

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification symbol FI H02J 7/00 H02J 7/00 P H02P 9/04 H02P 9/04 M (58) Fields surveyed (Int. Cl. ⁷ , DB Name) B60L 11/08 B60K 6/04 F02B 61/00 F02D 29/06 H02J 7/00 H02P 9/04

Claims (1)

(57) [Claim 1] Means for detecting a remaining capacity of a battery for supplying power to a motor for driving a vehicle, and means for obtaining a target power generation output from the remaining capacity are provided. A generator control device for a hybrid electric vehicle that controls an engine generator to generate electric power, comprising: an outside temperature sensor, a vehicle speed sensor, and a radiator capable of radiating heat based on a signal from the outside temperature sensor and a signal from the vehicle speed sensor. Means for determining an amount of power generation, means for determining an allowable power generation output without overheating the engine from the radiator radiable amount, and generating the target power generation output if the target power generation output is smaller than the allowable power generation output. Control means for controlling the power generation so as to generate the allowable power generation output when the target power generation output is equal to or greater than the allowable power generation output. A generator control device for a hybrid electric vehicle.