JP2005248875A - Engine controller of hybrid electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain the temperature of a catalyst installed in an exhaust gas purifying device to an appropriate temperature so that the catalyst successfully works, in a hybrid electric vehicle (HEV). <P>SOLUTION: In the HEV, electric power obtained by driving a generator 3 with an engine 2 is supplied to a motor 5 via an inverter 4, the motor 5 drives, and a driving wheel 7 rotates to run. Exhaust gas EG generated from the engine is purified with the exhaust gas purifying device 9 installed in an exhaust pipe 8 to be discharged into the air. In an engine controller 10A, when the engine 2 runs in a predetermined and more time in the idling , the engine 2 intermittently operates for generation only in a short time while the idling running. The catalyst of the exhaust gas purifying device 9 is heated by the high temperature exhaust gas EG generated by the generating operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine control device for a hybrid electric vehicle. In the present invention, the temperature of the catalyst provided in the exhaust gas purifying device is maintained at an appropriate temperature so that the catalyst operates satisfactorily.

  Due to social demands for environmental protection and energy saving on a global scale, the development and commercialization of electric vehicles (EV) and hybrid electric vehicles (HEV) are spurring.

  Hybrid electric vehicles include a series type and a parallel type. In series hybrid electric vehicles, the engine is used exclusively for driving the generator, and the motor drives the wheels with the generated power. On the other hand, in the parallel hybrid electric vehicle, the engine and the motor drive the wheels, and the two driving forces are selectively used according to the travel location and speed.

  In series-type hybrid electric vehicles, the engine is exclusively for power generation, so the engine can be operated at a constant speed without being affected by the vehicle speed or travel load. For this reason, it is possible to achieve both low fuel consumption and reduced exhaust gas by setting the power generation point in a good range of fuel consumption and exhaust gas. Such series hybrid electric vehicles are also applied to large buses and the like.

  Here, the configuration of a conventional series hybrid electric vehicle will be described with reference to FIG. In FIG. 3, 1 is a cooler compressor, 2 is an engine (for example, diesel engine), 3 is a generator, 4 is an inverter, 5 is a motor, 6 is a battery, 7 is a drive wheel, 8 is an exhaust pipe, and 9 is exhaust gas purification. Devices 10 are engine control devices (however, the control target is not limited to the engine 2, but the inverter 4 or the like is also the control target). In FIG. 3, the flow of electric power is indicated by black arrows, the direction of transmission of driving force is indicated by white arrows, and the flow of control information is indicated by dotted arrows.

  The engine driving force transmission system will be described. When the engine 2 is operated (rotation driven), the generator 3 is rotated by this driving force to generate electric power, and the cooler compressor 1 is operated as necessary to cool the cooler. Operation is possible. When the engine 2 is operated, a heater operation can be performed by a heater unit (not shown) using heat of a refrigerant (heated refrigerant) that cools the engine 2.

  The exhaust gas system will be described. Exhaust gas EG generated by operating the engine 2 is exhausted through the exhaust pipe 8. Since an exhaust gas purification device 9 is interposed in the middle of the exhaust pipe 8, PM (Particulate Matter) contained in the exhaust gas EG is captured by the exhaust gas purification device 9. For this reason, the exhaust gas EG that passes through the exhaust gas purification device 9 and is discharged into the atmosphere is a clean gas that hardly contains PM or the like.

  Note that a catalyst such as a well-known oxidation catalyst is provided in the exhaust gas purification device 9. In order to obtain reliable combustion removal of PM and sufficient catalytic activity, the catalyst of the exhaust gas purification device 9 needs to be at a temperature of a predetermined temperature or higher (for example, 250 ° C or higher, preferably 300 ° C or higher). There is.

  The power system will be described. When the power generated by the generator 3 or the power output from the battery 6 is supplied to the motor 5 via the inverter 4, the motor 5 is rotationally driven. The rotational driving force of the motor 5 is transmitted to the drive wheels 7, and the HEV travels. The HEV traveling speed is adjusted by adjusting the power supplied to the motor 5 by the inverter 4 and controlling the rotational speed of the motor 5. Further, the forward / reverse switching of the HEV is performed by adjusting the current state (phase rotation direction or current flow direction) supplied to the motor 5 by the inverter 4 to control the rotation direction (forward rotation, reverse rotation) of the motor 5. To do.

  When traveling downhill, the motor 5 is rotated by the rotational force of the drive wheels 7, and the motor 5 acts as a generator to generate regenerative power. The regenerative power is sent to the battery 6 via the inverter 4 and charged (charged).

  When the charging power charged in the battery 6 is insufficient, the power generated by the generator 3 is sent to the battery 6 via the inverter 4 to charge (accumulate) the battery 6.

  Explaining the control information system, the engine control apparatus 10 includes an idling start / stop control means 11 and an operation state control means 12.

  The engine control device 10 receives a vehicle speed signal a from a vehicle speed sensor (not shown) provided in the motor 5 and receives a charge rate signal b from a charge rate detection sensor (not shown) provided in the battery 6.

  Further, an idling start / stop signal c is input from the main switch SW1 of the idling start / stop system to the engine control device 10, a cooler switch ON / OFF signal d is input from the cooler switch SW2, and from the heater switch SW3. A heater switch ON / OFF signal e is input.

  Although details will be described later, when the main switch SW1 is turned on and an idling start / stop signal c is input to the engine control device 10, predetermined conditions are set so that the engine 2 does not perform unnecessary operations (such as idling operation). Then, control for forcibly stopping the operation of the engine 2 is performed.

  Further, the engine control device 10 sends a fuel injection amount control signal (output control signal) α to the engine 2. In accordance with the fuel injection amount control signal α, the amount of fuel supplied (injected) to the engine 2 is adjusted, and the output of the engine 2 is controlled. That is, the operating state of the engine 2 is controlled.

  The operation state of the engine 2 includes a “stop state”, an “idling operation state”, and a “40 kW power generation operation state”. The “stop state” is a state in which the engine 2 is stopped, and the “idling operation state” is a state in which the engine 2 is idling and the power generated by the generator 3 is substantially zero. The “power generation operation state” refers to a state in which the engine 2 is rotationally driven so that the power generated by the generator 3 is 40 kW (rated output power).

  Further, the engine control device 10 sends a power supply amount control signal β to the inverter 4. This power supply amount control signal β is also sent to the generator 3 via the inverter 4. The power supply amount (power) supplied (powered) to the motor 5 is controlled by the power supply amount control signal β. Note that the amount of power supplied (powered) from the battery 6 to the motor 5 is also controlled by the power amount control signal β.

Here, the operating state of the engine 2 that changes state according to each condition (charged state of the battery, etc.) will be described.
Control for changing the operation state of the engine 2 is performed by combining the control function of the idling start / stop control means 11 of the engine control device 10 and the control function of the operation state control means 12.

  The operation state control means 12 selects the idling operation state when the battery charge rate is high based on the battery charge rate obtained from the charge rate signal b, and the 40 kW power generation operation state when the battery charge rate is low. Select.

The idling start / stop control means 11 operates when the main switch SW1 is turned on and the idling start / stop signal c is input to the engine control device 10, and the idling operation state or 40 kW power generation is performed by the operation state control means 12. Even if the driving state is selected,
(I) When there is no vehicle speed obtained from the vehicle speed signal a (less than a predetermined vehicle speed (for example, 2 km / h)), the control of the idling operation or 40 kW power generation operation selected by the operation state control means 12 is canceled, Set to the stop state (see modes 1 and 4 in FIG. 4),
(Ii) Even when the vehicle speed obtained from the vehicle speed signal a is present (even if the vehicle speed is higher than a predetermined vehicle speed (for example, 2 km / h)), the cooler switch SW2 or the heater switch SW3 is OFF (cooler switch ON) When the / OFF signal d is not input or the heater switch ON / OFF signal e is not input), the idling operation and the control of the 40 kW power generation operation selected by the operation state control means 12 are canceled, and the operation is stopped. (Refer to mode 2 in FIG. 4).

  Eventually, the engine operation state finally selected by the idling start / stop control unit 11 and the operation state control unit 12 of the engine control device 10 is as shown in mode 1 to mode 7 shown in FIG. Then, the fuel injection amount control signal α and the power supply amount control signal β that are set to the engine operating states of the mode 1 to the mode 7 are sent from the engine control device 10 to the engine 2 and the inverter 4, so that the engine 2 The mode is in operation.

Each mode of FIG. 4 will be described as follows. First, in modes 1 to 5 in which the main switch SW1 of the idling start / stop system is turned on, the operation is as follows.
(1) In mode 1, since the battery charging rate is high, the idling operation state is selected by the operation state control means 12, but since there is no vehicle speed, the idling start / stop control means 11 finally selects the stop state.
(2) In mode 2, since the battery charging rate is high, the idling operation state is selected by the operation state control means 12, but since the cooler switch SW2 or the heater switch SW3 is OFF, the idling start / stop control means 11 Finally, the stop state is selected.
(3) In mode 3, the idling operation state is selected by the operation state control means 12 because the battery charging rate is high.
(4) In mode 4, the 40 kW power generation operation state is selected by the operation state control means 12 because the battery charging rate is low, but the stop state is finally selected by the idling start / stop control means 11 because there is no vehicle speed. .
(5) In mode 5, since the battery charge rate is low, the operation state control means 12 selects the 40 kW power generation operation state.

In modes 6 and 7 in which the main switch SW1 of the idling start / stop system is not turned on, the operation is as follows.
(6) In mode 6, since the battery charging rate is high, the idling operation state is selected by the operation state control means 12.
(7) In mode 7, since the battery charge rate is low, the operation state control means 12 selects the 40 kW power generation operation state.

JP 2003-239728 A

  In the conventional HEV described above, the engine 2 is idling in mode 3 or mode 6 as shown in FIG. Since this idling operation is a light load operation, the amount of exhaust gas EG discharged from the engine 2 is small, and the temperature of the exhaust gas EG is low. For this reason, if the idling operation state continues for a long time, the temperature of the catalyst of the exhaust gas purification device 9 may decrease, and the catalytic activity (catalyst function) of the catalyst may decrease. When the catalytic activity is thus reduced, there is a problem that the amount of PM or the like contained in the exhaust gas EG discharged to the atmosphere increases.

  In view of the above prior art, the present invention increases the temperature of the exhaust gas by switching the engine from the idling operation state to the power generation operation state when the idling operation state continues for a certain time or more, thereby increasing the catalyst temperature. It is an object of the present invention to provide an engine control device for a hybrid electric vehicle that can always maintain a catalyst at an optimum temperature.

The configuration of the present invention that solves the above problems includes an engine, an exhaust gas purification device that purifies exhaust gas exhausted from the engine, a generator driven by the engine, and electrical energy generated by the generator. In an engine control device of a hybrid electric vehicle comprising a battery for storing electricity and a motor electrically connected to the battery or the generator, and capable of traveling by the driving force of the motor,
The engine control device
An operation state control means capable of switching the operation state of the engine to at least idling operation or power generation operation according to the charging rate of the battery;
Time measuring means for measuring the time during which the engine is idling by the operating state control means;
When the idling operation time measured by the time measuring unit exceeds a predetermined time set in advance, the power generation switching unit that switches the operation state of the engine to the power generation operation,
It is characterized by providing.
The engine control device is not limited to the engine to be controlled.

In the configuration of the present invention, the engine control device
A second time measuring means for measuring a time during which the engine is generating and operating by the power generation switching means;
When the power generation operation time measured by the second time measuring unit exceeds a second predetermined time set in advance, the power generation operation of the engine by the power generation switching unit is terminated.

  Further, the configuration of the present invention is characterized in that the power generation operation by the power generation switching means generates power with a lower load than the power generation operation by the operation state control means.

In the present invention, when the idling operation time exceeds a predetermined time set in advance, the engine operating state is switched from the idling operation to the power generation operation, so that the temperature of the catalyst can be raised and the deterioration of the function of the exhaust gas purification device is prevented. can do.
At this time, the amount of power generated by the generator increases to switch to the power generation operation, but the surplus power (power generated by subtracting the power consumed by the motor from the generated power) is charged by the battery. Even if that happens, there will be no wasteful fuel consumption.

  Further, in the present invention, after the engine operating state is switched from the idling operation to the power generation operation, the power generation operation of the engine is terminated when the power generation operation time exceeds a preset second predetermined time. , Wasteful power generation operation can be suppressed.

  Furthermore, in the present invention, the output of the power generation operation after the engine operating state is switched from the idling operation to the power generation operation is performed with a lower load (lower output) than the power generation in the normal power generation operation. Therefore, the charging efficiency of the battery is improved, and no large electric power is applied to the battery, so that the battery can be prevented from being damaged (heat generation damage).

  The best mode for carrying out the present invention will be described below with reference to examples. In addition, the same part as a prior art attaches | subjects the same code | symbol, and description of the overlapping part is abbreviate | omitted.

FIG. 1 shows an engine control apparatus for a hybrid electric vehicle according to an embodiment of the present invention.
The engine control apparatus 10A according to the present embodiment includes not only the idling start / stop control means 11 and the operation state control means 12, but also the (first) timing means 13, the power generation switching means 14, and the second timing means 15. ing.
The structure of other parts is the same as that of the prior art shown in FIG.

  Also in this embodiment, the engine in each control mode as shown in FIG. 4 is controlled by the control functions of the idling start / stop control means 11 and the operation state control means 12 of the engine control apparatus 10A, as in the prior art shown in FIG. Operation state control of the engine 2 is performed so as to be in the operation state.

  Further, in this embodiment, when the engine 2 is idling in mode 3 or mode 6 in FIG. 4, the first time measuring means 13, the power generation switching means 14 and the second time measuring means 15 are unique to the present invention. Take control.

  When the engine 2 is idling, the first timing means 13 measures the time during which the engine 2 is idling (idling operation time).

  The power generation switching means 14 performs control for switching the operating state of the engine 2 to the power generation operation when the idling time measured by the first time measuring means 13 reaches a preset (first) predetermined time (for example, 10 minutes). To do. Thus, the “weak power generation operation state” is adopted as the power generation operation state when the operation state of the engine 2 is switched from the idling operation state to the power generation operation state by the power generation switching means 14. The “weak power generation operation state” is, for example, a “25 kW power generation operation state” in which the engine 2 is rotationally driven so that the generated power of the generator 3 is 25 kW (output power smaller than the rated output power). Say.

  The second time measuring means 15 starts time measurement (time keeping) from the time when the operation state of the engine 2 is switched from the idling operation state to the power generation operation state by the power generation switching means 14. When the time counted by the second timing means 15 reaches a preset second predetermined time (for example, 30 seconds), the power generation switching means 14 ends the “weak power generation operation state” of the engine.

  Here, a control procedure peculiar to the present embodiment (control procedure when the operation state of the engine 2 enters the idling operation state and this idling operation state continues for a predetermined time) will be described with reference to the flowchart of FIG.

  When the operation state of the engine 2 is in the idling operation state, the time is started by the first time measuring means 13 (steps 1 and 2).

  When the idling time measured by the first time measuring means 13 reaches a preset first predetermined time (for example, 10 minutes) (step 3), time measurement is started by the second time measuring means 15 (step 4). ) The operation state of the engine 2 is switched from the “idling operation state” to the “weak power generation operation state” by the power generation switching means 14 (step 5).

  When the time measured by the second time measuring means 15 reaches a preset second predetermined time (for example, 30 seconds), the generator switching means 14 ends the weak power generation operation state of the engine 2.

For this reason, for example, when the mode 3 or the mode 6 in FIG. 4 is continuously selected, the “30-second weak power generation operation” and the “10-minute idling operation state” are alternately performed.
That is, if the idling operation state continues for a long time, the weak power generation operation is intermittently performed during that time, and the temperature of the catalyst provided in the exhaust gas purification device 9 is raised by the high temperature exhaust gas EG generated during this weak power generation operation. be able to. Therefore, even if the idling operation state continues for a long time, the catalyst temperature can be maintained at an appropriate temperature (a temperature at which the catalyst activity is good). As a result, even if the idling operation state continues for a long time, the exhaust gas EG can be reliably purified by the exhaust gas purification device 9.

  Further, since the electric power generated by the weak power generation operation performed intermittently is stored in the battery 6, even if the weak power generation operation is performed, there is no wasteful fuel consumption.

  Further, since the generated power during the weak power generation operation is lower than the rated power, the power generated at this time can be efficiently stored in the battery 6. That is, the ratio of the power that is actually charged to the battery 6 can be increased with respect to the generated power. At this time, since the battery can be charged with low power, the battery 2 generates less heat due to the charging, and the battery 2 can be prevented from being damaged by heat.

  Needless to say, the present invention can be applied not only to the series HEV described above but also to a parallel HEV.

  INDUSTRIAL APPLICABILITY The present invention can be used in a hybrid electric vehicle to maintain the catalyst provided in the exhaust gas purification device at a good operating temperature even when the idling operation state continues for a long time.

1 is a block diagram showing a hybrid electric vehicle incorporating an engine control device according to an embodiment of the present invention. The flowchart which shows the control procedure of the Example of this invention. The block diagram which shows the hybrid electric vehicle incorporating the conventional engine control apparatus. Explanatory drawing which shows the driving | running state of an engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooler compressor 2 Engine 3 Generator 4 Inverter 5 Motor 6 Battery 7 Driving wheel 8 Exhaust pipe 9 Exhaust gas purification device 10, 10A Engine control device 11 Idling start / stop control means 12 Operating state control means 13 Timekeeping means 14 Power generation switching means 15 Second timing means

Claims (3)

An engine, an exhaust gas purifying device for purifying exhaust gas discharged from the engine, a generator driven by the engine, a battery for storing electrical energy generated by the generator, and the battery or the generator In an engine control device of a hybrid electric vehicle that is capable of traveling by a driving force of the motor.
The engine control device
An operation state control means capable of switching the operation state of the engine to at least idling operation or power generation operation according to the charging rate of the battery;
Time measuring means for measuring the time during which the engine is idling by the operating state control means;
When the idling operation time measured by the time measuring unit exceeds a predetermined time set in advance, the power generation switching unit that switches the operation state of the engine to the power generation operation,
An engine control device for a hybrid electric vehicle comprising: The engine control device
A second time measuring means for measuring a time during which the engine is generating and operating by the power generation switching means;
The power generation operation of the engine by the power generation switching means is terminated when the power generation operation time measured by the second time measuring means exceeds a preset second predetermined time. The engine control apparatus of the hybrid electric vehicle as described.   3. The engine control device for a hybrid electric vehicle according to claim 1, wherein the power generation operation by the power generation switching means generates power with a lower load than the power generation operation by the operation state control means.

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