JP2006280111A - Engine controller for hybrid electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine controller for a hybrid electric vehicle, which can prevent the overrevolution of a generator even in such a case that the revolution control of an engine is not performed normally. <P>SOLUTION: A hybrid electric vehicle, which is equipped with a motor 106 that generates the driving force of the vehicle, a battery 105 that supplies the motor 106 with power, a generator 102 that supplies at least either the motor 106 or the battery 105 with power, and an engine 101 that drives the generator, is equipped with an overrevolution judging means 130 which judges whether the generator 102 is in an overrevolution state or not and an emergency engine stop means which stops the engine when the overrevolution judging means 130 judges that the generator 102 is in an overrevolution state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine control device that prevents over-rotation of a generator used in a hybrid electric vehicle.

In recent years, a hybrid electric vehicle (HEV) equipped with a generator driven by an engine, a relatively high-voltage traveling battery, a traveling motor, and the like has been put into practical use. A parallel hybrid electric vehicle that travels by driving the driving wheels together with the driving force of the motor for driving, or a series hybrid electric vehicle that travels by driving the traveling motor with the power generated by the generator driven by the engine There is also a fusion of these features.
A series hybrid electric vehicle always travels with the driving force of a traveling motor, and either or both of the power charged in the battery and the power generated by the generator can be used to drive the traveling motor. is there.

  That is, if the amount of power stored in the battery is sufficient, the engine is stopped, and the running motor is driven by the battery power while the generator driven by the engine is not operating. When the electric power charged in the battery decreases, the engine is started, the electric generator generates electric power, the motor is driven by the generated electric power, and the electric power generated by the generator is charged into the battery. At this time, battery power may also be supplied to the traveling motor.

FIG. 5 is a schematic diagram showing a control system of an engine or an engine-driven generator of a conventional series hybrid electric vehicle.
As shown in FIG. 5, the conventional series hybrid electric vehicle includes an engine 101, a generator 102, an engine controller 103, a generator controller 104, and a battery 105.

The rotating shaft of the generator 102 is connected to the output shaft of the engine 101, and the generator 102 is electrically connected to the battery 105 and the motor 106.
The generator controller 104 sets a target power generation amount based on information on the state of charge (SOC) of the battery 105 and the load (power consumption) of the motor 106. Then, based on the target power generation amount, the target rotational speed of the generator and the target rotational speed of the engine are set so that power generation is performed with good energy efficiency and exhaust gas characteristics, and the target engine rotational speed is set to the engine controller. 103 is instructed.

  Information from an engine speed sensor (crank angle sensor) provided in the engine 101 is input to the engine controller 103. When an instruction of the target engine speed is input from the generator controller 104, the engine controller 103 starts the engine and sucks the engine so that the engine speed detected by the engine speed sensor becomes the target engine speed. The air amount and fuel injection amount (including ignition timing in the case of a gasoline engine) are controlled.

  Therefore, when the battery 105 is sufficiently charged, the motor 106 is driven using the electric power of the battery 105 to travel. When the power charged in the battery 105 decreases, the generator controller 104 sets the target power generation amount and the target engine speed, and instructs the engine controller 103 about the target engine speed. The engine controller 103 starts the engine 101 based on an instruction from the generator controller 104 and performs feedback control based on the detected value of the engine speed so that the engine speed becomes the target speed.

  When the engine 101 is operating, the electric power generated by the generator 102 is used to drive the motor 106 and travel, and the battery 105 is charged by the electric power generated by the generator 102. Further, the electric power of the battery 105 is also applied to drive the motor 106.

  By the way, in the above-described prior art, for example, the engine speed is not normally controlled due to some malfunction such as erroneous detection of the actual engine speed or failure of the engine controller 103 itself, and the engine 101 increases the target speed. When the rotation speed exceeds 1, the rotational force of the engine 101 is also applied to the generator 102 as it is, so that the rotation speed of the generator 102 greatly exceeds the target rotation speed as the rotation speed of the engine 101 increases. .

In such a case, since the generator 102 generates power at a rotational speed higher than the target rotational speed, not only energy efficiency and exhaust gas performance are deteriorated during power generation, but also the rotational speed of the generator 102 is the allowable rotational speed. If the value exceeds, the generator 102 may be damaged such as seizure.
In addition, the present invention is not limited to a series hybrid electric vehicle. In a parallel hybrid electric vehicle including a generator driven by an engine that is also used for traveling and a clutch that connects and disconnects power transmission between the engine and driving wheels, the engine The above problem is also conceivable when the power is used exclusively for power generation and travels only with the driving force of the motor.

  The present invention was devised in view of such problems, and is an engine for a hybrid electric vehicle that can reliably prevent over-rotation of a generator even when engine speed control is not normally performed. An object is to provide a control device.

  In order to achieve the above object, an engine control apparatus according to a first aspect of the present invention includes a motor that generates a driving force of a vehicle, a battery that supplies electric power to the motor, and at least one of the motor and the battery. In a hybrid electric vehicle including a generator that supplies power to one side and an engine that drives the generator, an overspeed determination unit that determines whether the generator is in an overspeed state, and the overspeed determination unit Is provided with emergency engine stop means for stopping the engine when it is determined that the generator is in an overspeed state.

The engine control device according to a second aspect of the present invention is the engine control device according to the first aspect, wherein the emergency engine stop means determines that the generator is in an overspeed state by the overspeed determination means. The control power source of the engine controller for controlling the engine speed is cut off.
An engine control device according to a third aspect of the present invention is the engine control device according to the first or second aspect, further comprising a generator rotational speed detection means for detecting a rotational speed of the generator, wherein the overspeed determination means includes the The generator is determined to be in an over-rotation state when the rotation speed of the generator detected by the generator rotation speed detection means exceeds a predetermined value set in advance.

  The engine control device according to a fourth aspect of the present invention is the engine control device according to the first or second aspect, further comprising a generated power detection means for detecting the generated power of the generator, wherein the overspeed determination means is the generated power When the generated power detected by the detection means exceeds a predetermined value set in advance, it is determined that the generator is in an overspeed state.

Therefore, according to the engine control apparatus of the first aspect of the present invention, when the generator is determined to be in the overspeed state by the overspeed determination means, the engine is stopped. Without rotating at the rotation speed, it is possible to prevent the generator from being damaged due to excessive rotation.
According to the engine control device of the present invention as set forth in claim 2, when it is determined that the generator is in the overspeed state, the control power supply of the engine controller is cut off, so that the engine is surely stopped. Thus, over-rotation of the generator can be prevented.

According to the engine control device of the present invention as set forth in claim 3, the rotational speed of the generator is detected, and the detected rotational speed of the generator is compared with a predetermined value. Can be determined to be in an over-rotation state.
According to the engine control device of the present invention as set forth in claim 4, since the generated power of the generator is detected and the detected generated power is compared with a predetermined value, the generator is reliably over-rotated. The state can be determined.

[First Embodiment]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 are for explaining the engine control apparatus according to the first embodiment of the present invention. FIG. 1 is a schematic diagram showing a control system of the engine and the generator. FIG. 2 is a flowchart for engine control in the present embodiment. In FIG. 1, components corresponding to the prior art in FIG.

  As shown in FIG. 1, the engine control apparatus of this embodiment includes an engine 101, a generator 102 driven by the engine, an engine controller 103, a generator controller 104, a battery (high-voltage battery) 105, and a motor, as in the prior art. 106, and further includes a switch 120 on an input line of a control power supply to the engine controller 103, and a solenoid 121 that opens and closes the switch 120 when energized on the generator controller 104 side.

The control power for the engine controller is supplied from a low voltage battery (for example, 24V) (not shown). The solenoid 121 is connected to the generator controller 104.
The engine 101 is provided with an engine speed sensor 110 that detects the engine speed Ne, and the generator is provided with a generator speed sensor 111 that detects the generator speed Ng.

The generator 102 is connected to the engine 101 so that power can be transmitted, and is electrically connected to the battery 105 and the motor 106.
The battery charge state (SOC, here, the charge rate) is input from the battery 104 to the generator controller 104, and accelerator opening information is input from the ECU (not shown) to detect the required power of the motor 106. . Further, the generator controller 104 is in a state where the energy efficiency and the exhaust gas characteristics are good according to the required power generation amount based on the state of charge (SOC) of the battery 105 and the output (power consumption) of the motor 106. In order to generate electric power, the target rotational speed Neg of the generator and the target rotational speed Net of the engine corresponding thereto are set, the target engine rotational speed is instructed to the engine controller 103, and the field current of the generator 102 is set. Control.

Further, a detected value of the rotational speed of the generator 102 is input from a generator rotational speed sensor 111 provided in the generator 102 to a functional element (overspeed determination means) 130 provided in the generator controller 104, in overspeed determination unit 130, a preset the rotation speed detection value Ng of the generator 102 which is inputted with a predetermined value Ng ₀ are compared, or the generator 102 is overspeed condition is determined.

Furthermore, the generator controller 104 has a function of controlling connection / disconnection of the solenoid 121. When the overspeed determination unit 130 determines that the generator 102 is in the overspeed state, the generator 120 is energized to switch the switch 120. It is possible to cut off the control power supply of the engine controller 103 by turning OFF. That is, here, the generator controller 104, the solenoid 121, and the switch 120 function as emergency engine stop means.
When an instruction for the target engine speed is input from the generator controller 104, the engine controller 103 starts the engine 101 so that the engine speed Ne detected by the engine speed sensor 110 becomes the target engine speed Net. In addition, the intake air amount and fuel injection amount of the engine 101 are controlled.

  Since the engine control apparatus according to an embodiment of the present invention is configured as described above, the motor 106 is driven using the electric power of the battery 105 when the battery 105 is sufficiently charged. Further, when the electric power charged in the battery 105 decreases, the generator controller 104 issues a start command to the engine controller 103, and the engine controller 103 starts the engine 101 based on an instruction from the generator controller 104, and the engine controller 103 Feedback control is performed based on the detection information of the engine speed sensor so that 101 operates at the target engine speed Net.

During the operation of the engine 101, the electric power generated by the generator 102 is used to drive the motor 106 and travel, and the battery 105 is charged by the electric power generated by the generator 102.
If the control by the engine controller 103 and the generator controller 104 is further demonstrated, control as shown, for example in FIG. 2 will be performed. The control in step S40 is performed by the engine controller 103, and the other control is performed by the generator controller 104.

First, in step S <b> 10, the generator controller 104 compares the charging rate SOC of the battery 105 input from the battery 105 with a predetermined value SOC <b> ₀ set in advance to confirm the charging state of the battery 105.
In step S10, when the charging rate of the battery 105 is higher than the predetermined value SOC ₀ , it is determined that the battery 105 is sufficiently charged and the process returns to the start. If the charging rate of battery 105 is lower than predetermined value SOC ₀ , it is determined that the power charged in battery 105 has decreased, and the process proceeds to step S20.

In step S20, power generation is performed in accordance with the required power generation amount based on the battery charging status confirmed in step S10 and the power required by the motor 106, and with good energy efficiency and exhaust gas characteristics. The setting of the target rotational speed Neg of the generator and the target rotational speed Net of the engine corresponding to the generator is calculated.
In step S30, the engine controller 104 is instructed to set the target engine speed Net.

In step S40, the engine controller 103 starts the engine 101, and sets the intake air amount and fuel injection amount of the engine 101 so that the engine speed information input from the engine speed sensor 110 becomes the target engine speed. Control.
In step S50, the generator controller 104 acquires the rotation speed of the generator 102 based on the input of the detection result of the generator rotation speed sensor 111.

In step S60, the overspeed determination unit 130, the magnitude relationship between the predetermined rotational speed Ng ₀ it is compared with the preset rotational speed Ng of the generator 102 has been detected in step S50, the generator 102 rpm Ng of When the detected value is smaller than the predetermined rotation speed Ng ₀ , the process returns to the start, and the voltage of the battery 105 is compared with the predetermined value V ₀ again.
On the other hand, when the rotational speed Ng of the generator 102 is equal to or greater than the predetermined rotational speed Ng ₀ , the over-rotation determining means 130 determines that the generator 102 is over-rotating and proceeds to step S70. In step S70, the generator controller 104 energizes the solenoid 121. Then, the switch 120 is turned off by the energized solenoid 121, and the control power input to the engine controller 103 is cut off.

If the control power input to the engine controller 103 is cut in step S70, the engine controller 103 naturally does not operate. As a result, the fuel injection control by the engine controller 103 is not performed, so that the engine 101 is cut off and stopped.
Therefore, in a case where the engine speed control by the engine controller 103 is not normally performed due to a malfunction of the engine speed sensor 110 or the like, and the engine 101 rotates significantly exceeding the target engine speed, the generator controller 104 When the generator rotation speed sensor 111 detects over-rotation of the generator 102, the control power input to the engine controller 103 is cut and the engine 101 is stopped, so that the generator 102 rotating in conjunction with the rotation of the engine 102 The rotation is also stopped, and the generator 102 does not over-rotate any more, and it is possible to prevent the generator 102 from being damaged due to over-rotation.

[Second Embodiment]
3 and 4 are schematic diagrams showing an engine and generator control system for explaining an engine control apparatus according to a second embodiment of the present invention. The same reference numerals as those in FIG. 1 denote the same elements, and in FIG. 4, steps having the same reference numerals as those in FIG. For this reason, a part of the description is omitted for parts similar to those in FIGS.

  As shown in FIG. 3, in the present embodiment, the current value 112 of the generated power output from the generator 102 and the voltage value Es of the generated power output from the generator 102 are detected by the generator 102. The point which is provided with the voltage sensor 113 to detect, and can detect the electric power generated by the generator 102 by detecting an electric current value and a voltage value is different from the thing of 1st Embodiment.

That is, in the present embodiment, the generator controller 104 detects the generated power of the generator 102 by multiplying the detected value Is of the current sensor 112 and the detected value Es of the voltage sensor to calculate the generated power Ws. To do.
Since the electric power Ws generated by the generator 102 is determined by the rotational speed Ng of the generator 102, the overspeed determination means 130 detects the generated electric power Ws of the generator 102 instead of detecting the rotational speed Ng of the generator 102. It can be determined that the generator 102 is in an overspeed state.

Since the engine control apparatus in the present embodiment is configured as described above, the engine is controlled according to the flow shown in FIG.
First, as in the first embodiment, the process proceeds to steps S10 to S30, and in step S40, the engine speed information input from the engine speed sensor 110 by the engine controller 103 starting the engine 101 is the target engine. When the intake air amount and the fuel injection amount of the engine 101 are controlled so as to achieve the rotational speed, the process proceeds to step S55 in FIG.

In S55, the generator controller 104 multiplies the detection results Is and Es of the current sensor 112 and the voltage sensor 113 provided in the generator 102 to obtain the actual generated power Ws (= Is × Es) of the generator 102. Detect.
Then, in step S65, the magnitude relationship between the generated power Ws and the predetermined power W ₀ of the generator 102 detected in step S55 are compared, the start when the generated power of the generator 102 is smaller than a predetermined power W ₀ The battery charge status is confirmed again.

If the generated power Ws of the generator 102 is equal to or greater than the predetermined power W ₀ , the process proceeds to step S75. In step S75, the generator controller 104 energizes the solenoid 121 as in the first embodiment. The switch 120 is turned off by the energized solenoid 121, and the control power input to the engine controller 103 is cut off.
Therefore, the generator controller 104 can detect over-rotation of the generator 102 based on the detection results of the current sensor 112 and the voltage sensor 113 provided in the generator 102, and turn off the control power of the engine controller. Thus, the engine 101 can be stopped to prevent the generator 102 from over-rotating, and further, the generator 102 can be prevented from being damaged.

[Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the generator overspeed is detected by comparing the actual rotational speed Ng of the generator with the predetermined rotational speed Ng ₀ or by comparing the generated power Ws of the generator with the predetermined power W _0. However, it may be determined that the generator is in an over-rotation state based on the detected values of both the rotational speed and the generated power. In this case, the overspeed state of the generator can be determined more accurately.

Further, the predetermined rotation speed Ng ₀ and the predetermined power W ₀ can be appropriately set within the range of the allowable rotation speed or the allowable power generation amount of the generator 102. For example, even in the range of the allowable rotational speed of the generator, the target rotational speed of the generator 102 set by the generator controller is set to a predetermined rotational speed Ng ₀ in consideration of energy efficiency and exhaust gas performance degradation due to excessive rotation. As a value obtained by adding a predetermined allowable value to Ngt, the predetermined rotation speed Ng ₀ may be a value that varies depending on the target rotation speed Ngt of the generator 102.

  In the above-described embodiment, the engine 101 is stopped by cutting off the control power supply of the engine controller 103, but the stopping means of the engine 101 is not limited to that of the above-described embodiment. For example, if it is determined that the generator 102 is in an overspeed state, for example, in the case of a diesel engine, the engine is stopped by mechanically cutting off the fuel supply to the engine, such as by setting the mechanical governor to a fuel supply stop state. It may be.

  Further, the present invention is not limited to a series hybrid electric vehicle, but a parallel hybrid electric vehicle including a generator driven by an engine also used for traveling and a clutch for connecting and disconnecting power transmission between the engine and driving wheels. In this case, the present invention is effective when applied to the case where the engine is used exclusively for power generation and travels only by the driving force of the motor.

It is a schematic diagram which shows the control system of the engine and generator which concern on 1st Embodiment of this invention. It is a flowchart which shows control of the engine and generator which concern on 1st Embodiment of this invention. It is a schematic diagram which shows the control system of the engine and generator which concern on 2nd Embodiment of this invention. It is a flowchart which shows control of the engine and generator which concern on 2nd Embodiment of this invention. It is a flowchart which shows control of the engine and generator in a prior art.

Explanation of symbols

101 Engine 102 Generator 103 Engine Controller 104 Generator Controller 105 Battery (High Voltage Battery)
106 Motor 110 Engine speed sensor 111 Generator speed sensor 112 Current sensor 113 Voltage sensor 120 Switch 121 Solenoid 130 Over-rotation judging means

Claims (4)

A motor that generates the driving force of the vehicle;
A battery for powering the motor;
A generator for supplying power to at least one of the motor and the battery;
An engine that drives the generator;
In a hybrid electric vehicle equipped with
Over-rotation determination means for determining whether the generator is in an over-rotation state;
An engine control device for a hybrid electric vehicle, comprising: an emergency engine stop unit that stops the engine when the overspeed determination unit determines that the generator is in an overspeed state. The emergency engine stop means cuts off a control power source of an engine controller that controls the number of revolutions of the engine when the overspeed determination means determines that the generator is in an overspeed state. The engine control device for a hybrid electric vehicle according to claim 1. Comprising a generator rotation speed detection means for detecting the rotation speed of the generator;
The over-rotation determination means determines that the generator is in an over-rotation state when the rotation speed of the generator detected by the generator rotation speed detection means exceeds a predetermined value set in advance. The engine control device for a hybrid electric vehicle according to claim 1 or 2. Comprising generated power detection means for detecting the generated power of the generator;
The over-rotation determination unit determines that the generator is in an over-rotation state when the generated power detected by the generated power detection unit exceeds a predetermined value set in advance. 3. An engine control device for a hybrid electric vehicle according to 2.

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