JP3539357B2 - Engine operation control device for hybrid electric vehicle - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine operation control device for a hybrid electric vehicle.
[0002]
[Prior art]
2. Description of the Related Art Hitherto, a hybrid electric vehicle in which a driving force of a vehicle is obtained by combining an internal combustion engine (engine) and an electric motor (motor) has been developed and put into practical use. Such hybrid electric vehicles include a series hybrid electric vehicle that uses an engine exclusively as a power supply source for a motor, and a parallel hybrid electric vehicle in which both an output shaft of an engine and an output shaft of a motor are mechanically connected to drive wheels. Electric vehicles are known.
[0003]
Among them, in a series hybrid electric vehicle, a motor is operated by power supply from a battery to run the vehicle. Then, as shown in FIG. 4, when the remaining power of the battery is less than the first predetermined value (for example, 60%), the engine is operated to drive the generator, and the battery is charged and the power is supplied to the motor. Do it. Further, as shown in FIG. 4, when the remaining capacity of the battery 1 recovers to a second predetermined value (for example, 65%) or more by the charging at this time, the operation of the engine 4 is stopped, and the power generation is stopped. It has become.
[0004]
When the engine water temperature of the series hybrid electric vehicle as described above is lower than a predetermined temperature (for example, 60 ° C.), a warm-up operation is performed to protect the engine. In this case, the warm-up operation is performed for a predetermined period of time (for example, 60 seconds) with the generator set to no load.
This will be described with reference to the flowchart shown in FIG. 5. First, when the operation of the engine is started, it is determined in step S10 whether or not the engine water temperature is lower than a predetermined temperature (60 ° C.). Proceed to step S20, otherwise proceed to step S40. When the process proceeds to step S20, the warm-up operation is started and the time of the warm-up operation is counted. Then, the warm-up operation is continued through step S30 until the warm-up operation time reaches 60 seconds, and after 60 seconds elapses, the process proceeds from step S20 to step S40, and the warm-up operation ends.
[0005]
[Problems to be solved by the invention]
However, at the start of the warm-up operation, the remaining capacity of the battery may be close to the first predetermined value. However, if the remaining capacity of the battery is already small at this time, the remaining capacity of the battery during the warm-up operation may increase. It is conceivable that the temperature will further decrease and adversely affect the power performance of the vehicle.
[0006]
That is, during normal running, the engine is started when the remaining capacity of the battery falls below the first predetermined value, as described above. Therefore, the remaining battery capacity at this time is, of course, near the first predetermined value, as described above. No major issues arise. On the other hand, for example, when the battery remaining capacity is already about 20% at the time of starting the vehicle and the engine water temperature is low, the remaining capacity of the battery is further reduced during the warm-up operation, which hinders the running of the vehicle. The problem arises.
[0007]
In addition, it is conceivable that a load is applied to the generator to generate electricity without performing the warm-up operation when the engine water temperature is low.However, such an operation has a bad effect on the engine. Warm-up operation cannot be omitted.
SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and it is possible to prevent a situation in which the remaining capacity of a battery decreases so as to hinder traveling during a warm-up operation of an engine. It is an object to provide an engine operation control device.
[0008]
[Means for Solving the Problems]
In the engine operation control device for a hybrid electric vehicle according to the first aspect of the present invention, when the engine is started, if the temperature of the cooling water of the engine is lower than a predetermined temperature based on the detection information from the water temperature detection means, the control means warms up. Machine operation is executed. In addition, the warm-up operation time at this time is set based on the remaining capacity of the battery obtained by the remaining capacity detection means, and during the warm-up operation, the generator is not loaded and the rotation speed of the engine is substantially constant. Is held . As a result, the warm-up operation according to the remaining capacity of the battery can be executed, and it is possible to prevent the remaining capacity of the battery from being reduced so as to hinder the running during the warm-up operation of the engine.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an engine operation control device for a hybrid electric vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a main part thereof.
As shown in FIG. 1, a battery 1 is mounted on a hybrid electric vehicle, and the battery 1 is electrically connected to an electric motor (motor) 3 via a motor controller 2. The motor 3 is connected to a driving wheel side of a vehicle (not shown), and the hybrid electric vehicle runs by driving the motor 3.
[0010]
The hybrid electric vehicle is also provided with an engine 4, and an output side of the engine 4 is mechanically connected to a generator 5 for supplying electric power to the battery 1 and the motor 3. When the generator 5 is driven by the engine 4, electric power corresponding to the load of the generator 5 is generated.
In addition, the vehicle is provided with a control device (or simply referred to as a controller) 6 as control means to which various sensors are connected. The engine 4 and the generator 5 are controlled by a control signal from the controller 6. The operation is controlled on the basis of the operation.
[0011]
On the other hand, an accelerator opening sensor 8 is attached to the accelerator pedal 7, and an output corresponding to the amount of depression of the accelerator pedal 7 by the driver is input to the motor controller 2 and the controller 6. An instruction output to the motor 3 is set by the motor controller 2 based on an output signal of the accelerator opening sensor 8, and the motor 3 is driven according to the instruction output to the motor 3.
[0012]
Further, the battery 1 is provided with a remaining capacity detection means (specific gravity meter) 10 for detecting the remaining power of the electric power, and the remaining capacity of the battery 1 is detected by the specific gravity meter 10 and inputted to the controller 6. Has become. Normally, when the remaining capacity of the battery 1 falls below a first predetermined value (for example, 60%), the engine 4 is operated to start charging. When the remaining capacity becomes equal to or more than a second predetermined value (for example, 65%), the operation of the engine 4 is stopped.
[0013]
Further, the engine 4 is provided with a water temperature sensor (water temperature detecting means) 22 for detecting the temperature of the cooling water in the water jacket 21. When the engine 4 starts, based on detection information from the water temperature sensor, When the water temperature is lower than a predetermined temperature (for example, 60 ° C.), the controller 6 performs a warm-up operation of the engine 4.
[0014]
During the warm-up operation, the generator 6 is set to a no-load state (a state in which no power is generated) by the controller 6, and the engine rotation speed is maintained at a substantially constant rotation speed (for example, 1500 rpm).
A map as shown in FIG. 3 is stored in the controller 6, and the warm-up operation time of the engine 4 is set according to the remaining capacity of the battery 1 detected by the hydrometer 10. ing.
[0015]
That is, if the remaining capacity of the battery 1 is 60% or more, a fixed warm-up operation time (for example, 60 seconds) is set. If the remaining capacity of the battery 1 is 30% or less, the warm-up operation is performed. A fixed warm-up operation time (for example, 10 sec) smaller than the operation time is set. When the remaining capacity of the battery 1 is between 30% and 60%, the warm-up operation time is set shorter as the remaining capacity decreases.
[0016]
That is, since the power of the battery 1 is consumed even during the warm-up operation of the engine 4, if the vehicle is started while the remaining capacity of the battery 1 is low, for example, about 30%, the warm-up operation of the engine 4 is executed. It is conceivable that the remaining capacity of the battery 1 may be reduced to such an extent as to hinder traveling while the vehicle is running. Therefore, in the present invention, when the remaining capacity of the battery 1 is low, the warm-up operation time is set as short as possible.
[0017]
Further, if it is detected that the engine coolant temperature has reached 60 ° C. or higher before the warm-up operation time set in the map shown in FIG. 3 has elapsed, the warm-up operation is terminated at this point. .
Note that the setting map of the warm-up operation time shown in FIG. 3 is an example of the characteristic, and is not necessarily limited to such a characteristic. What is necessary is just to have the characteristic which becomes short.
[0018]
Further, in the present embodiment, 10 seconds is set as the minimum value of the warm-up operation time, but this is the minimum warm-up operation time required when the engine 4 is started in a cold state. It is set based on specifications and the like.
Since the engine operation control device of the hybrid electric vehicle as one embodiment of the present invention is configured as described above, the warm-up operation of the engine 4 is executed according to, for example, the flowchart shown in FIG.
[0019]
That is, when a start condition of the engine 4 such as a state where the remaining capacity of the battery 1 becomes less than a predetermined value is satisfied, this routine starts, and first, at step S1, the engine water temperature from the water temperature sensor 22 is taken. If the engine water temperature is equal to or higher than the predetermined temperature (for example, 60 ° C.), the process proceeds to step S6, in which the warm-up operation of the engine 4 is prohibited and the normal engine operation is performed. In this case, a load is applied to the generator 5 based on a control signal from the controller 6 to quickly generate power.
[0020]
On the other hand, if the engine water temperature is lower than the predetermined temperature, the process proceeds to step S2, where the warm-up operation of the engine 4 is executed, and in step S3 the engine warm-up is performed based on the engine water temperature using a map as shown in FIG. The machine operation time is set. During the warm-up operation, the generator 5 is controlled to have no load by the control signal from the controller 6, and the engine rotation speed is kept substantially constant.
[0021]
Thereafter, the process proceeds from step S3 to step S4, and it is determined whether the warm-up operation time set in step S3 has elapsed. If the set time has elapsed, the process proceeds to step S6, and the warm-up operation is prohibited. If the set warm-up operation time has not elapsed, the process proceeds to step S5, where the warm-up operation is continued and returns.
[0022]
Therefore, according to the engine operation control device for a hybrid electric vehicle of the present invention, when the vehicle is started in a state where the remaining capacity of the battery 1 is greatly reduced (for example, when the vehicle is started for a long time after leaving the vehicle unattended), A situation in which the remaining capacity of the battery 1 further decreases during the warm-up operation of the engine 4 and adversely affects the power performance of the vehicle is reliably avoided, and the warm-up operation of the engine 4 is performed only for a minimum necessary time. Since it is executed, it has a unique advantage that an adverse effect on the engine 4 can be avoided. In addition, since it is only necessary to add a simple logic without adding a new part to the conventional technology, there is an advantage that an increase in vehicle weight and an increase in cost are not caused.
[0023]
The engine operation control device for a hybrid electric vehicle according to the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention. For example, instead of providing the map shown in FIG. 3 in the controller 6, the warm-up operation time may be set by calculation using the remaining battery capacity as a parameter. Further, the numerical values used in the above-described embodiment can be appropriately changed according to the characteristics of the engine 4, the generator 1, the motor 3, and the like.
[0024]
【The invention's effect】
As described above in detail, according to the engine operation control device for a hybrid electric vehicle of the present invention, when the vehicle is started in a state where the remaining capacity of the battery is greatly reduced, the battery is further increased during the warm-up operation of the engine. The unique advantage of this system is that it can reliably prevent the situation where the remaining capacity of the vehicle will be reduced and affect the vehicle's power performance, and it also performs the warm-up operation of the engine only for the minimum necessary time, thus avoiding any adverse effects on the engine. have. In addition, since there is no need to add new parts to the conventional technology and only to add a simple logic, there is an advantage that increase in vehicle weight and cost is not caused.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a main configuration of an engine operation control device for a hybrid electric vehicle according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a procedure of an engine operation control device for a hybrid electric vehicle according to an embodiment of the present invention.
FIG. 3 is a map for explaining characteristics of the engine operation control device of the hybrid electric vehicle according to one embodiment of the present invention.
FIG. 4 is a diagram for explaining a conventional technique.
FIG. 5 is a diagram for explaining a conventional technique.
[Explanation of symbols]
1 Battery 3 Electric motor
4 Engine 6 control means (controller)
10 Remaining capacity detection means (specific gravity meter)
22 Water temperature detecting means (water temperature sensor)

Claims (1)

A generator mechanically connected to the engine, and a battery electrically connected to the generator and the electric motor; and operating the engine to drive the generator to charge and / or charge the battery. An engine operation control device for a hybrid electric vehicle that supplies power to the electric motor,
Water temperature detecting means for detecting the temperature of the cooling water of the engine;
Remaining capacity detection means for detecting the remaining power of the battery;
Control means for performing a warm-up operation when the temperature of the cooling water detected by the water temperature detecting means is lower than a predetermined temperature when the engine is started,
The control means keeps the rotation speed of the engine at a substantially constant rotation speed by setting the generator at no load during the warm-up operation, and the warm-up operation time of the battery obtained by the remaining capacity detection means. An engine operation control device for a hybrid electric vehicle, wherein the setting is performed based on a state of charge .

Images