JPH11245657A - Engine control device for hybrid electric vehicle - Google Patents

Abstract

(57) [Summary] The present invention relates to an engine control device for a hybrid electric vehicle, and aims to improve fuel economy by suppressing the operation of the engine as much as possible when using a heating device. SOLUTION: When a hybrid electric vehicle is in an engine stop state, an operation start detection means 2 detects a heating device 1.
When the operation start of the engine 17 is detected, and when the coolant temperature detecting means 3 detects that the cooling water temperature of the engine 17 is lower than a predetermined temperature, the engine control means 18 starts the engine 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an engine control device for a hybrid electric vehicle.

[0002]

2. Description of the Related Art Conventionally, engines and electric motors (motors)
Various types of so-called hybrid electric vehicles have been developed, and some of them have already been put into practical use. In general, such a hybrid electric vehicle is provided with a cooling and heating device similar to that of a normal engine-driven vehicle. That is, a compressor driven by the engine is provided, cooling is performed by operating the compressor, a heat exchanger is provided on a cooling water passage of the engine, and heating is performed using warm air obtained by the heat exchanger. Is performed.

[0003] The running modes of the hybrid electric vehicle described above include two running modes, a battery running mode and a hybrid running mode.
Here, the battery running mode is a running mode used when the remaining capacity of the battery is relatively large, and is a mode in which the engine is stopped, the power is supplied from the battery to the motor, and the vehicle runs by the driving force of the motor. Say. Also,
The hybrid traveling mode is a traveling mode used when the remaining capacity of the battery is relatively small, and refers to a mode in which the engine is operated to travel. In this hybrid driving mode, a system that drives the engine to generate electric power and supplies this electric power to the motor (a series hybrid electric vehicle) or uses the driving force of the engine as the driving force for driving Systems (parallel hybrid electric vehicles).

[0004]

However, when cooling and heating are used when the engine is stopped in a battery running mode or the like, cooling and heating are not performed unless the engine is started. In other words, when performing cooling, it is necessary to start the engine to operate the compressor, and when performing heating, it is necessary to operate the engine-driven water pump to circulate the cooling water. Cooling and heating cannot be performed while the engine is stopped.

For this reason, when cooling and heating are performed when the engine is stopped, it is necessary to start the engine simultaneously with switching on the cooling and heating device. However, in such a configuration, the efficiency of the engine is reduced and fuel consumption is reduced. There is a problem that the rate also worsens. For example, when the temperature of the cooling water of the engine is already high, it is only necessary to send the cooling water to the heat exchanger, and it is not preferable to start the engine for this purpose because energy efficiency is reduced.

[0006] Japanese Patent Application Laid-Open No. Hei 6-286449 discloses a technique in which an engine is started immediately when an air conditioner switch is turned on, and thereafter, a temperature inside and outside the vehicle and a set temperature are detected to control the air conditioner. However, even in this technique, when the heating is used, the engine is always in an operating state, and thus, similarly to the above, there is a problem that the efficiency of the engine is reduced and the fuel consumption rate is also deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an engine control device for a hybrid electric vehicle, in which the operation of the engine is suppressed as much as possible when the air conditioner is used to improve fuel efficiency. The purpose is to provide.

[0008]

In the engine control apparatus for a hybrid electric vehicle according to the present invention, when the hybrid electric vehicle is in an engine stopped state, the operation start detecting means detects the start of operation of the heating device, and the water temperature detecting means. Detects that the engine coolant temperature is lower than a predetermined temperature, the engine control means starts the engine.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an engine control device for a hybrid electric vehicle according to an embodiment of the present invention; FIG. It is a flowchart for explaining the operation. First, the main configuration of a hybrid electric vehicle to which the present invention is applied will be described with reference to FIG. 1. In the figure, 11 is a motor (motor), 13 is wheels, 14 is an inverter, 15 is a battery, 16 is a generator, 17 is an engine.

The hybrid electric vehicle in this embodiment is a so-called series hybrid electric vehicle, and an engine 17 is provided mainly for driving a generator 16 to supply electric power to a battery 15. I have. That is, the vehicle is configured to run by the rotational driving force of the motor (electric motor) 11. A battery 15 and a generator 16 are electrically connected to the motor 11 via an inverter 14, and driving wheels 13 are connected to an output shaft of the motor 11.

Further, the inverter 14, the generator 16 and the engine 17 are connected to a controller 18 as engine control means, and the controller 18 controls the operations of the inverter 14, the generator 16 and the engine 17 respectively. It has become. Further, the battery 15 is provided with a charge capacity sensor 19 capable of detecting the remaining power of the battery 15, and this charge capacity sensor 19 is also connected to the controller 18 as shown.

The controller 18 changes the running mode of the vehicle to one of the battery running mode and the hybrid running mode based on the detection signal from the charging capacity sensor 19 and the detection signals from other sensors (not shown). It is designed to switch. That is, when the remaining capacity of the electric power stored in the battery 15 is detected by the charging capacity sensor 19 to be equal to or more than a predetermined value,
The controller 18 stops the operation of the engine 17 and the generator 16, and drives the motor 11 by the electric power stored in the battery 15 (battery running mode).

When the remaining capacity of the electric power stored in the battery 15 decreases and it is detected that the remaining capacity is equal to or less than a predetermined value, the controller 18 operates the engine 17. Then, the generator 17 is operated by the engine 17, and the electric power obtained by the generator 16 is stored in the battery 15, and the electric power is supplied to the motor 11 via the inverter 14. (Hybrid running mode).

By the way, as shown in FIG. 1, the engine control device of the hybrid electric vehicle is provided with an auto air conditioner 1 functioning as a cooling device and a heating device. The auto air conditioner 1 has the same configuration as a normal engine-driven automobile, and includes a compressor (not shown) driven by an engine 17 and the like.

Therefore, when cooling is performed, the compressor is driven by the engine 17 to compress the refrigerant, and then the refrigerant is supplied to an evaporator (not shown) as in a normal automobile. The air cooled by the evaporator is taken into the vehicle interior to cool the interior of the vehicle. When heating is performed, the engine 1
The cooling water heated to a high temperature by the heat of 7 is sent to a heat exchanger provided in a cooling system (not shown), and the warm air obtained by this heat exchanger is taken into the vehicle interior.

As shown in FIG. 1, the hybrid electric vehicle is provided with an electric water pump 4 for circulating cooling water, and when the engine 17 is stopped and the temperature of the cooling water is low. When heating is performed when the temperature is sufficiently high, the electric water pump 4 circulates cooling water without starting the engine 17.

This is to avoid operating the engine 17 only for the purpose of circulating the cooling water. That is, the engine 17 is provided with a mechanical water pump (not shown). During the operation of the engine 17, the cooling water is circulated through the cooling system by the mechanical water pump to cool the engine 17. Has become.

However, when heating is performed when the engine 17 is stopped, if the cooling water is at a sufficiently high temperature, the cooling water may be simply circulated, and it is not preferable to operate the engine 17 for this purpose. Therefore, as described above, in the engine control device for a hybrid electric vehicle according to the present invention, the electric water pump 4 is newly provided, and when the temperature of the cooling water is sufficiently high when the engine 17 is stopped, the electric water pump is provided. The pump 4 is operated to circulate the cooling water to perform heating.

When heating is performed while the engine 17 is operating, the electric water pump 4 does not need to be operated because the mechanical water pump is operating. Therefore, in this case, the electric water pump 4 is not used. Is controlled to a stopped state. The control at the time of operating the automatic air conditioner 1 will be described more specifically below.

As shown in FIG. 1, the automatic air conditioner 1 is provided with an operation switch 2.
By operating, the operation of the automatic air conditioner 1 can be switched on and off. The operation switch 2 is connected to the controller 18.
The operation status of the operation switch 2 is monitored by the controller 18. That is, the operation switch 2 functions as an operation start detecting unit that detects the start of operation of the automatic air conditioner 1.

Further, the above-mentioned cooling system is provided with a water temperature sensor 3 as water temperature detecting means, and temperature information of the cooling water is inputted to the controller 18.
In the engine control device for a hybrid electric vehicle according to the present invention, the engine
Is stopped, the operation switch 2 detects an operation start operation for the automatic air conditioner 1, and when this operation detects the start of heating, the controller 18 performs the following control. .

First, the coolant temperature of the engine 17 is detected by the coolant temperature sensor 3, and it is determined whether the coolant temperature is higher than a predetermined temperature. When the temperature is higher than the predetermined temperature (when the cooling water temperature is sufficiently high), the electric water pump 4 is operated to circulate the cooling water. Thereby, the high-temperature cooling water circulates through the cooling system without operating the engine 17, and the warm air is taken into the vehicle interior through the heat exchanger, so that efficient heating can be performed. .

When the cooling water temperature is lower than the predetermined temperature, the controller 18 sets a control signal for starting the engine 17 and starts the engine 17. When the engine 17 operates, the cooling water is warmed by the heat of the engine 17 and the mechanical water pump attached to the engine 17 is driven to circulate the cooling water through the cooling system.

When the coolant temperature rises due to the operation of the engine 17 and the coolant temperature sensor 3 detects that the coolant temperature has risen to a predetermined temperature, an operation stop signal for the engine 17 is set by the controller 18 and the engine 17 is stopped. 17 stops. At this time, the engine 17
The operation of the electric water pump 4 is started almost simultaneously with the stop of the operation, and the cooling water is circulated by the electric water pump 4.

The engine 1 in a battery running mode or the like
When the start of the operation of the cooling device is detected at the time of stopping the engine 7, the engine 17 is immediately started to drive the compressor. Since the engine control device for a hybrid electric vehicle as one embodiment of the present invention is configured as described above, an example of its operation will be described below with reference to the flowchart shown in FIG.

First, the engine 1 in the battery running mode or the like
At the time of the 7 stop, in step S1, it is determined whether the heating operation condition is satisfied. Here, the heating operation condition is, for example, when the operation switch 2 of the auto air conditioner 1 is turned on, the set temperature is higher than the outside temperature, and the blower switch (not shown) is on. It is time.

When the heating operation condition is not satisfied, the process proceeds to step S2, where the engine 17 is stopped in step S2. If it is determined in step S1 that the heating operation condition is satisfied, the process proceeds to step S3, and it is determined whether the temperature of the cooling water is higher than a predetermined value. Here, when it is determined that the temperature of the cooling water is lower than the predetermined value, the process proceeds to step S4, in which the engine 17 is forcibly started. As a result, the temperature of the cooling water rises and the engine 17
The mechanical water pump is driven by the
At 5, heating is performed.

On the other hand, if it is determined in step S3 that the temperature of the cooling water is higher than the predetermined value, the process proceeds to step S6. If the engine 17 is operating, the engine 17 is stopped. This state is maintained if 17 is stopped. Subsequently, the process proceeds to step S7, in which the electric water pump 4 is operated, and the electric water pump 4 circulates the cooling water. Thereby, step S
At 5, heating will be performed.

As described in detail above, according to the engine control apparatus for a hybrid electric vehicle of the present invention, at the start of heating, the engine 17 is started only when the cooling water temperature is equal to or lower than a predetermined temperature that does not satisfy the heating capacity. When the cooling water temperature becomes equal to or higher than the predetermined temperature, the engine 17 is stopped, so that there is an advantage that unnecessary idle operation is eliminated and fuel efficiency is improved. That is, in the battery running mode, the idling operation of the engine 17 is suppressed as much as possible, thereby improving the fuel consumption rate. Further, by operating the electric water pump 4 when the engine is stopped, there is an advantage that heating can be performed quickly and the heating capacity is improved.

The engine control device for a hybrid electric vehicle according to the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention. For example, in the present embodiment, a mechanical water pump driven by an engine and an electric water pump are used together as the water pump, but only the electric water pump may be used.

As a hybrid electric vehicle,
In addition to the above, a parallel hybrid electric vehicle that travels by appropriately using the driving force of the engine and the driving force of the motor, or a type that has characteristics of both a series hybrid electric vehicle and a parallel hybrid electric vehicle Hybrid electric vehicle.

The heating device does not necessarily have to be the automatic air conditioner 1, but may be a manual air conditioner or a heater mechanism having only a heating function.

[0033]

As described in detail above, according to the engine control apparatus for a hybrid electric vehicle of the present invention, when the hybrid electric vehicle is in the engine stopped state, the operation start detecting means detects the start of operation of the heating device. And, when the cooling water temperature of the engine is detected to be lower than the predetermined temperature by the water temperature detecting means, the engine is started by the engine controlling means, so that the heating capacity when the engine is stopped is improved, and There is an advantage that the idling operation of the engine can be suppressed as much as possible, and the fuel economy performance is improved.

[Brief description of the drawings]

FIG. 1 is a schematic functional block diagram showing main functions of an engine control device for a hybrid electric vehicle as one embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the engine control device of the hybrid electric vehicle as one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 auto air conditioner including heating device 2 operation switch (operation start detection means) 3 water temperature sensor (water temperature detection means) 11 motor (electric motor) 17 engine 18 controller (engine control means)

Claims (1)

[Claims] 1. A hybrid electric vehicle equipped with an engine and an electric motor, wherein: an operation start detecting means for detecting a start of operation of a heating device; a water temperature detecting means for detecting a cooling water temperature of the engine; In the state, when the operation start detecting means detects the operation start of the heating device and the water temperature detecting means detects that the cooling water temperature of the engine is lower than a predetermined temperature, the engine is started. An engine control device for a hybrid electric vehicle, comprising: engine control means.