WO2014192423A1

WO2014192423A1 - Control structure for adjusting temperature of battery

Info

Publication number: WO2014192423A1
Application number: PCT/JP2014/060103
Authority: WO
Inventors: 横山　亘; 圭二三宅
Original assignee: 株式会社豊田自動織機
Priority date: 2013-05-29
Filing date: 2014-04-07
Publication date: 2014-12-04
Also published as: JP2014231786A

Abstract

The purpose of the present invention is to provide a control structure for adjusting the temperature of a battery mounted in a vehicle, the control structure achieving further improvement in fuel economy. A control structure (10) for adjusting the temperature of a battery (33) mounted in a vehicle is provided with an engine room (20) that houses an engine (30) and the battery (33). An ECU (50) executes efficiency decrease control for decreasing the efficiency of the engine (30) when the temperature (t) of the battery (33) is lower than a predetermined temperature threshold (t1), the battery acceptable electric power (Win) is smaller than a predetermined electric power threshold (W1), and the vehicle speed (v) is lower than a predetermined vehicle speed threshold (v1).

Description

Control structure for adjusting battery temperature

The present invention relates to a control structure for adjusting the temperature of a battery.

In a vehicle equipped with a battery, if the temperature of the battery is low, the acceptable power (regenerative power) of the battery will be small, and the fuel efficiency will deteriorate. Therefore, temperature control of the battery is important to improve fuel consumption.

At the time of engine start, there is known a technique for controlling charging / discharging of the battery to thereby control the temperature of the battery. An example of such a technique is described in US Pat.

JP 2000-92614 A

However, in the prior art, there is a problem that sufficient temperature control can not always be realized. For example, in the technique of Patent Document 1, when the battery temperature is low, the amount of heat generated by charging and discharging is small because the acceptable power is small, so the battery can not be sufficiently warmed. As a result, fuel consumption may be deteriorated.

The present invention has been made to solve such a problem, and it is an object of the present invention to provide a control structure for adjusting the temperature of a battery, which can further improve the fuel consumption.

In order to solve the above-mentioned problems, a control structure for adjusting the temperature of the battery according to the present invention is a control structure for adjusting the temperature of the battery mounted on the vehicle, and accommodates the internal combustion engine and the battery The control device includes an engine room and a control device that controls the operation of the internal combustion engine, and the control device has a battery temperature lower than a predetermined temperature threshold, an acceptable power of the battery lower than the predetermined power threshold, and a vehicle speed When the vehicle speed is smaller than a predetermined vehicle speed threshold value, efficiency reduction control is performed to reduce the efficiency of the internal combustion engine.

Due to the efficiency reduction control, the efficiency is reduced and the heat generation amount is increased, and the temperature of the battery in the engine room is increased.

According to the control structure for adjusting the temperature of the battery of the present invention, when the temperature of the battery is low, control is performed to reduce the efficiency of the internal combustion engine. It will be accepted. For this reason, fuel consumption improves in the long run.

It is a figure which shows the example of a structure of the control structure which concerns on Embodiment 1 of this invention. It is a flowchart which shows the example of the flow of a process of ECU of FIG. It is a figure which shows the example of operation control of the engine by ECU of FIG.

Hereinafter, an embodiment of the present invention will be described based on the attached drawings.
Embodiment 1
FIG. 1 shows an example of the configuration of a control structure 10 according to the first embodiment of the present invention. Control structure 10 is a control structure for adjusting the temperature of battery 33 mounted on a vehicle, for example.

The control structure 10 comprises an engine compartment 20. Further, the control structure 10 includes an engine 30 which is an internal combustion engine, a generator 31 which rotates in conjunction with the engine 30 to generate electric power, a rectifier 32 which is connected to the generator 31 to convert alternating current to direct current, and rectifier 32 , And a temperature sensor 34 for detecting the temperature of the battery 33. The generator 31 may be a motor generator having a function of supplying power to the engine 30 to drive it. The battery 33 is, for example, a lithium ion battery, a nickel hydrogen battery, a lead battery, a capacitor or the like.

The control structure 10 includes an engine controller 40, a power generation controller 41, an SOC meter 42, a vehicle speed sensor 43, and an ECU 50.
The ECU 50 is a control device, and transmits commands to the engine controller 40 and the power generation controller 41 to control the overall operation of the control structure 10. Engine controller 40 controls the operation of engine 30 in accordance with a command from ECU 50, and controls, for example, the torque and rotational speed of engine 30. The power generation controller 41 detects the number of revolutions of the engine 30, and the current value and the voltage value of the rectifier 32, and controls the operation of the generator 31 in accordance with the command from the ECU 50 based on these values. For example, the field current of the generator 31 is controlled.

The SOC meter 42 detects the terminal voltage of the battery 33, and the current value and voltage value of the rectifier 32, measures the state of charge of the battery 33 based on these values, and transmits it to the ECU 50. The vehicle speed sensor 43 detects the vehicle speed of the vehicle and transmits it to the ECU 50. Further, the above-described temperature sensor 34 detects the temperature of the battery 33 and transmits it to the ECU 50. The ECU 50 controls the engine controller 40 and the power generation controller 41 based on the information. Further, the ECU 50 transmits an instruction to the engine controller 40 as described above, and transmits a starter signal to the engine 30 to control the operation of the engine 30.

The engine 30, the generator 31, the rectifier 32, the battery 33 and the temperature sensor 34 are housed in the engine room 20. In the present embodiment, the heat radiation from the engine 30 reaches the entire engine compartment 20, but otherwise, at least the battery 33 is disposed in the area where the heat radiation of the engine 30 can reach.

Although the engine controller 40, the power generation controller 41, and the SOC meter 42 are accommodated in the engine room 20 in the present embodiment, they may not be accommodated in the engine room 20. Further, although the ECU 50 and the vehicle speed sensor 43 are not accommodated in the engine room 20 in the present embodiment, they may be accommodated in the engine room 20.

The operation of the control structure 10 configured as described above will be described below.
FIG. 2 is a flowchart showing the flow of processing of the ECU 50. Although the flowchart of FIG. 2 ends at the “end” terminal, the process of FIG. 2 is repeatedly executed in practice.
First, the ECU 50 acquires the battery temperature t from the temperature sensor 34 (step S1).

Next, the ECU 50 determines whether the acquired battery temperature t is smaller than a predetermined temperature threshold value t1 (step S2). The value representing the temperature threshold value t1 can be stored in advance in the storage means of the ECU 50, for example. The temperature threshold value t1 can be set to, for example, 10 ° C. If the battery temperature t is equal to or higher than the temperature threshold t1, the ECU 50 ends the process. This corresponds to a situation where the acceptable power is sufficiently large, for example due to the battery temperature being high enough. In this case, since the power generation in the following step S6 and the efficiency reduction control in the following step S9 are not executed, the fuel consumption can be maintained higher.

If the battery temperature t is smaller than the temperature threshold value t1, the ECU 50 acquires the battery acceptable power Win based on the information from the temperature sensor 34 and the SOC meter 42 (step S3). The battery acceptable power Win may, for example, be predefined as a function of the battery temperature t and the state of charge.

Next, the ECU 50 determines whether the acquired battery acceptable power Win is larger than a predetermined power threshold W1 (step S4). The value representing the power threshold value W1 can be stored, for example, in advance in the storage means of the ECU 50. The battery acceptable power Win may be represented by a negative value, in which case the absolute value of the battery acceptable power Win is used for the determination.

If the battery acceptable power Win is larger than the power threshold W1, the ECU 50 instructs the engine controller 40 to increase the output of the engine 30 by an amount corresponding to the battery acceptable power Win (step S5). The controller 31 instructs the power generation controller 41 to generate the battery acceptable power Win (step S6). As a result, for example, the radiant heat of the engine 30 is increased. Further, for example, maximum regeneration (regeneration of battery acceptable electric power Win) is performed according to the state of battery 33, so heat generation by the internal resistance (I ² R) of battery 33 is increased. Thus, the battery 33 is warmed up. Here, the ECU 50 ends the process of FIG.

In step S4, when the battery acceptable power Win is equal to or less than the power threshold W1 (or smaller than the power threshold W1), the ECU 50 acquires the vehicle speed v from the vehicle speed sensor 43 (step S7). Then, the ECU 50 determines whether the acquired vehicle speed v is larger than a predetermined vehicle speed threshold v1 (step S8). The value representing the vehicle speed threshold v1 can be stored in advance in the storage means of the ECU 50, for example.

When the vehicle speed v is equal to or less than the vehicle speed threshold v1 (or smaller than the vehicle speed threshold v1), the ECU 50 executes efficiency reduction control to reduce the efficiency of the engine 30 (step S9). That is, for example, when the battery temperature t is smaller than the temperature threshold t1, the battery acceptable power Win is smaller than the power threshold W1, and the vehicle speed v is smaller than the vehicle speed threshold v1, the ECU 50 executes the efficiency reduction control. Do. Here, “efficiency” refers to, for example, the conversion efficiency when converting fuel to power, and for example, control to increase the amount of heat generation while maintaining the power (product of torque and rotational speed) output from the engine 30 It corresponds to efficiency reduction control.

Although the efficiency reduction control may be executed in any way, a specific example of the operation control of the engine 30 in the present embodiment will be described next. In the present embodiment, the efficiency reduction control is control that increases the rotational speed of the engine 30 while maintaining the power of the engine 30.

FIG. 3 shows a graph in which the rotational speed of the engine 30 is taken on the horizontal axis and the torque is taken on the vertical axis. The equal power lines P shown by solid lines are all a set of operating points corresponding to a constant power. Different equal power lines P respectively correspond to different powers, and the power is larger at the upper right. Further, the equal efficiency lines E indicated by broken lines are a set of operating points each corresponding to a certain efficiency. Different equal efficiency lines E correspond to different efficiencies, with the inner one being more efficient.

Now, it is assumed that the operating point of the engine 30 is at point X1. The control F for moving this operating point to the point X2 corresponds to the efficiency reduction control. That is, since the points X1 and X2 are on the same equal power line P, the output power is the same, but the points X1 and X2 are on different equal efficiency lines E, so the efficiencies are different (point X1 Is more efficient).

As a result of such efficiency reduction control, the efficiency of the engine 30 decreases, so the calorific value of the engine 30 increases and the temperature in the engine room 20 rises. Since the battery 33 is disposed in the engine compartment 20, the temperature of the battery 33 also rises accordingly. As a result, larger regenerative power can be accepted earlier. Therefore, the regeneration can be efficiently performed, and the fuel consumption is improved in the long run. Moreover, as a result, the time for warm-up operation can be reduced, and the total amount of toxic gas (carbon dioxide etc.) generated can be reduced.

In the present embodiment, the efficiency reduction control is limited to control for increasing the rotational speed of the engine 30 while maintaining the power of the engine 30. That is, by increasing the rotational speed of engine 30, control is performed on the assumption that the efficiency necessarily decreases (though it may theoretically be the case where the efficiency increases as a result, but such a case Included in control). This control focuses on the fact that the operating point of the engine 30 is always on the side where the rotational speed is higher (or more likely) than the point of optimizing the efficiency. It is possible to omit the process of determining whether the efficiency is reduced by controlling the increase or decrease.

When the vehicle speed v is larger than the vehicle speed threshold v1 in step S8 of FIG. 2, the ECU 50 ends the process. This corresponds to, for example, a situation in which the heat escapes to the outside of the vehicle even if the warm-up is performed because the vehicle speed is large and the traveling wind is strong, and the effect of the warm-up process is reduced. In this case, since the ECU 50 does not execute the efficiency reduction control, it is possible to avoid the small effect warm-up processing and maintain the fuel consumption higher.

In the above-described first embodiment, the expression "maintaining the power of engine 30" means that points X1 and X2 are located on exactly the same equal power line, but this is not strict. However, they may be located on substantially the same equal power line. Or what is necessary is to keep the power of the engine 30 as identical as possible within the range of practical control.

In the first embodiment described above, the efficiency reduction control is control for increasing the rotational speed of the engine 30 while maintaining the power of the engine 30, but the efficiency reduction control may have other contents. For example, control may be performed to move the operating point of the engine 30 in the direction of reducing the efficiency while maintaining the power of the engine 30. If this control is represented in FIG. 3, control is made to move the operating point toward the outside of the equal efficiency line E along a certain equal power line P (this control depends on the position of the operating point of the first embodiment). Consistent with control).

Further, the control for reducing the efficiency of the engine 30 is not limited to the control for moving the operating point along the same equal power line P, as long as it is control for increasing the amount of heat generated in the engine 30. For example, control may be made to change both the power and the efficiency, and consequently to increase the amount of heat generated in the engine 30. The movement of a specific operating point that produces such a result can be appropriately designed by those skilled in the art.

In the first embodiment, steps S7 and S8 may be omitted. That is, when the battery acceptable power Win is larger than the power threshold W1 in step S4, the ECU 50 may execute step S9 (efficiency reduction control to reduce the efficiency of the engine 30) regardless of the vehicle speed.

Claims

A control structure for adjusting the temperature of a battery mounted on a vehicle,
An engine room housing an internal combustion engine and a battery;
A controller for controlling the operation of the internal combustion engine;
The controller is
The temperature of the battery is less than a predetermined temperature threshold,
A control structure for executing efficiency reduction control that reduces the efficiency of the internal combustion engine when the acceptable power of the battery is smaller than a predetermined power threshold and the vehicle speed is smaller than a predetermined vehicle speed threshold.
The control structure according to claim 1, wherein the efficiency reduction control is control for increasing the rotational speed of the internal combustion engine while maintaining the power of the internal combustion engine.
The control structure according to claim 1, wherein the control device does not execute the efficiency reduction control when the vehicle speed is larger than the vehicle speed threshold.