JP4254363B2 - Warm-up control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a warm-up control device including a heat exchanger that performs heat exchange between cooling water of an internal combustion engine and hydraulic fluid of an automatic transmission.
[0002]
[Prior art]
In recent years, in vehicles equipped with an automatic transmission (AT), for the purpose of improving fuel efficiency, the transmission efficiency of the automatic transmission is controlled by performing lock-up control that directly connects the input side and the output side of the torque converter of the automatic transmission. There is something to improve. Generally, if lockup control is performed before the end of warm-up of the automatic transmission (when the temperature of the hydraulic oil in the automatic transmission is low), drivability may be adversely affected. Lock-up control is prohibited during a period when the temperature (hereinafter referred to as “AT oil temperature”) is low.
[0003]
For this reason, if the automatic transmission warms up (AT oil temperature rise) is slow after the internal combustion engine is started, the time from the start of the internal combustion engine until the lockup control is permitted becomes longer, and the fuel consumption by the lockup control becomes longer. The improvement effect cannot be obtained early. Moreover, since the friction loss of the automatic transmission increases before the end of warming up of the automatic transmission (when the AT oil temperature is low), the fuel consumption deterioration period due to the increased friction loss also becomes longer.
[0004]
As a countermeasure, for example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-161747), a heat exchanger that performs heat exchange between cooling water of the internal combustion engine and hydraulic fluid of the automatic transmission ( A so-called ATF warmer) is provided, and after the warm-up operation of the internal combustion engine is finished, the coolant warmed by the internal combustion engine is circulated to the ATF warmer and the hydraulic fluid of the automatic transmission is heated by the heat of the coolant to Some are designed to warm up.
[0005]
[Patent Document 1]
JP 2002-161747 (first page to second page, etc.)
[0006]
[Problems to be solved by the invention]
By the way, in order to maximize the fuel efficiency improvement effect of the early warm-up of the internal combustion engine and the early warm-up of the automatic transmission, warm up the internal combustion engine (cooling water) and the automatic transmission (hydraulic oil) in a well-balanced manner. Therefore, it is necessary to finish the warm-up of both parties as soon as possible.
[0007]
However, in the warming-up system of Patent Document 1, the cooling water of the internal combustion engine is not circulated to the ATF warmer until the warming-up operation of the internal combustion engine is completed. The automatic transmission will be warmed up (AT oil temperature rise) will be delayed. For this reason, it takes a long time from the start of the internal combustion engine until the lockup control is permitted, and it is difficult to obtain the fuel efficiency improvement effect by the lockup control at an early stage. In addition, an increase in fuel consumption due to friction loss before the completion of warm-up of the automatic transmission cannot be improved at an early stage.
[0008]
The present invention has been made in view of such circumstances. Therefore, the object of the present invention is to warm up the internal combustion engine and the automatic transmission in a well-balanced manner after the start and finish the warm-up of both as soon as possible. An object of the present invention is to provide a warm-up control device that can effectively reduce the fuel consumption required until both warm-ups are completed.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a warm-up control device according to claim 1 of the present invention is a system including a heat exchanger that performs heat exchange between cooling water of an internal combustion engine and hydraulic fluid of an automatic transmission. The operation region (hereinafter referred to as “lock-up region”) in which lock-up control is performed to directly connect the input side and output side of the torque converter of the automatic transmission can be changed according to the operation mode and the gear position. And, by controlling the flow rate of the cooling water circulating to the heat exchanger according to the lockup region, the temperature of the cooling water of the internal combustion engine (hereinafter referred to as “engine cooling water temperature”) and the hydraulic oil of the automatic transmission Characterized in that it is provided with warm-up control means for controlling the temperature (hereinafter referred to as “AT oil temperature”).
[0011]
In general, in a system for performing lock-up control of the automatic transmission, so that to change the lock-up area is an operating region where the lock-up control in accordance with the operating mode and gear position are executed. For this reason, even if the automatic transmission warm-up (a rise in AT oil temperature) is promoted under the same conditions and the lock-up control is permitted early, if the lock-up region changes, the execution frequency of the lock-up control also changes. The fuel efficiency improvement effect due to the early warm-up of the automatic transmission also varies depending on the lockup region.
[0012]
Therefore, in the invention according to claim 1, the engine coolant temperature and the AT oil temperature are controlled by controlling the flow rate of the coolant circulating to the heat exchanger according to the lock-up region that changes according to the operation mode and the shift speed. I am doing so . In this way, when the lockup region is a region where the fuel efficiency improvement effect due to the early warm-up of the automatic transmission is relatively large, the flow rate of the cooling water circulating to the heat exchanger is increased, and the fuel efficiency improvement effect is achieved. When the larger warm-up (automatic transmission warm-up) is preferentially promoted, or when the lock-up region is a region where the fuel efficiency improvement effect due to the early warm-up of the automatic transmission is small, the heat exchanger It is possible to perform warm-up control according to the lock-up region by preferentially promoting warm-up (warm-up of the internal combustion engine) having a greater fuel efficiency improvement effect by reducing the flow rate of circulating cooling water. Thereby, the stable fuel-consumption improvement effect which is not influenced by the lockup area | region can be acquired.
[0013]
Further, as in claim 2 , the flow rate of the cooling water circulating to the heat exchanger may be controlled based on at least one of the engine cooling water temperature and the AT oil temperature and the lockup region. In this way, while monitoring the engine coolant temperature and the AT oil temperature, it is possible to control the flow rate of the coolant circulating to the heat exchanger according to the lock-up region, and the warm-up control with a greater fuel efficiency improvement effect Can be realized.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
<< Embodiment (1) >>
Hereinafter, an embodiment (1) of the present invention will be described with reference to FIGS. First, a schematic configuration of the entire system will be described with reference to FIG. A mechanical water pump 12 driven by the power of the engine 11 is provided at an inlet of a cooling water passage (water jacket) of the engine 11 which is an internal combustion engine. The outlet of the cooling water passage of the engine 11 and the inlet of the radiator 13 are connected by a cooling water circulation pipe 14, and the outlet of the radiator 13 and the suction port of the mechanical water pump 12 are connected by a cooling water circulation pipe 15. As a result, a cooling water circulation circuit 16 is constructed in which the cooling water circulates in the path of the cooling water passage of the engine 11 → the cooling water circulation pipe 14 → the radiator 13 → the cooling water circulation pipe 15 → the mechanical water pump 12 → the cooling water passage of the engine 11. ing.
[0018]
The cooling water circulation circuit 16 is provided with a bypass flow path 17 in parallel with the radiator 13, and both ends of the bypass flow path 17 are connected to the cooling water circulation pipes 14 and 15. A flow rate adjusting valve 18 is provided at the junction of the bypass flow path 17 and the cooling water circulation pipe 15. The flow rate adjusting valve 18 is configured by an electromagnetic valve that can adjust a flow rate ratio between the flow rate of the cooling water flowing through the bypass passage 17 (bypass flow rate) and the flow rate of the cooling water flowing through the radiator 13 (radiator flow rate). Yes. A coolant temperature sensor 19 that detects the temperature of the coolant is provided in the coolant circulation pipe 14 on the coolant outlet side of the engine 11.
[0019]
In addition, a heating hot water circuit 20 is connected to the cooling water circulation circuit 16 in parallel to the engine 11. A heater 21 for heating is provided in the middle of the hot water circuit 20, and an ATF warmer 23 (heat exchanger) for warming the hydraulic oil of the automatic transmission 22 is provided downstream (or upstream) of the heater 21. Is provided. The ATF warmer 23 is connected to a hydraulic oil circulation circuit 24 through which the hydraulic oil of the automatic transmission 22 circulates. Cooling water of the engine 11 flowing through the hot water circuit 20 (cooling water heated by the engine 11) and hydraulic oil circulation. Heat is exchanged with the hydraulic fluid of the automatic transmission 22 that flows through the circuit 24. The hydraulic oil circulation circuit 24 is provided with an oil temperature sensor 25 that detects the temperature of the hydraulic oil.
[0020]
A warmer flow rate adjustment valve 26 is provided upstream of the hot water circuit 20. The warmer flow rate adjustment valve 26 is configured by an electromagnetic valve that can adjust the flow rate of the cooling water circulating to the ATF warmer 23 by adjusting the flow rate of the cooling water circulating to the hot water circuit 20.
[0021]
Outputs of various sensors such as the water temperature sensor 19 and the oil temperature sensor 25 described above are input to a control circuit (hereinafter referred to as “ECU”) 27. The ECU 27 is mainly composed of a microcomputer, and by executing a water temperature control program (not shown) stored in its ROM (storage medium), the ECU 27 controls the flow rate adjusting valve 18 to control the bypass flow rate and the radiator flow rate. Adjust to control the temperature of the cooling water.
[0022]
The AT-ECU (not shown) that controls the automatic transmission 22 is connected to an input side and an output side of a torque converter (not shown) of the automatic transmission 22 when the driving state is in a predetermined driving range. By performing lock-up control that makes the direct connection state and flex lock-up control that makes the semi-direct connection state (sliding state slightly), the transmission efficiency of the automatic transmission 22 is improved and the fuel efficiency is improved.
[0023]
As shown in FIG. 2, an operation region (lock-up region) in which lockup control is executed and an operation region (flex lock-up region) in which flex lockup control is executed include, for example, vehicle speed and throttle opening. The map is set accordingly. Since this map is set for each operation mode and shift speed, the lockup area and flex lockup area change when the operation mode and shift speed change.
[0024]
In general, if lock-up control is performed before the end of warm-up of the automatic transmission 22 (when the temperature of hydraulic oil in the automatic transmission 22 is low), drivability may be adversely affected. The lock-up control is prohibited during a period when the temperature of the hydraulic oil of the automatic transmission 22 (hereinafter referred to as “AT oil temperature”) is lower than a predetermined value.
[0025]
Further, the ECU 27 (or AT-ECU) executes a warm-up control program shown in FIG. 3 to be described later, so that when the engine 11 and the automatic transmission 22 are warmed up, the engine coolant temperature Thw and the AT oil temperature Tho Based on the above, the flow rate Qatf (warmer flow rate Qatf) of the cooling water flowing through the ATF warmer 23 is controlled. As a result, the amount of heat transferred from the cooling water warmed by the engine 11 to the hydraulic oil of the automatic transmission 22 via the ATF warmer 23 is controlled, and the engine cooling water temperature Thw and the AT oil temperature Thho are each appropriately operated. The temperature is raised and the engine 11 and the automatic transmission 22 are warmed up in a balanced manner.
[0026]
Warm-up control program shown in FIG. 3, Ru is executed in a predetermined cycle, for example, after the ignition switch is turned on (not shown). When this program is started, first, in step 101, using the map shown in FIG. 4, according to the engine coolant temperature Thw detected by the water temperature sensor 19 and the AT oil temperature Th detected by the oil temperature sensor 25, A warmer flow rate Qatf (a flow rate of cooling water flowing through the ATF warmer 23) is calculated.
[0027]
The map of FIG. 4 shows, for example, that the warmer flow rate Qatf is Q1 → Q2 → Q3 from the region where the AT oil temperature Th is high and the engine coolant temperature Thw is low toward the region where the AT oil temperature Th is low and the engine coolant temperature Thw is high. It is set so that the amount of heat transferred from the coolant warmed by the engine 11 to the hydraulic oil of the automatic transmission 22 increases in order of Q4.
Thereafter, the process proceeds to step 102, and the opening degree of the warmer flow rate adjusting valve 26 is controlled so as to be the warmer flow rate Qatf set in step 101.
[0028]
The execution example and comparative example of the warm-up control of the present embodiment (1) described above will be described with reference to the time charts of FIGS. FIG. 5 is a time chart showing the behavior of the engine cooling water temperature Thw and the AT oil temperature Tho after the engine is started with the engine cooling water temperature Thw and the AT oil temperature Th being about 40 ° C. FIG. It is a time chart which shows the behavior of engine cooling water temperature Thw and AT oil temperature Tho after starting an engine in the state where AT oil temperature Th is about 0 ° C.
[0029]
In the comparative example shown in FIGS. 5 and 6, the opening of the engine is controlled in order to control the warmer flow rate Qatf by controlling the opening degree of the warmer flow rate adjustment valve 26 under a constant condition regardless of the engine coolant temperature Thw and the AT oil temperature Tho. Immediately after the opening of the warmer flow rate adjustment valve 26 is too large, the amount of heat transferred from the coolant to the hydraulic oil becomes excessive, and the increase in the engine coolant temperature Thw is delayed. For this reason, the warm-up of the engine 11 is delayed, and the fuel efficiency improvement effect and the emission reduction effect cannot be sufficiently obtained.
[0030]
On the other hand, in the present embodiment (1), the opening degree of the warmer flow rate adjustment valve 26 is controlled so as to become the warmer flow rate Qatf set by a map or the like according to the engine coolant temperature Thw and the AT oil temperature Tho. While monitoring the engine coolant temperature Thw and the AT oil temperature Th, the amount of heat transferred from the coolant to the hydraulic oil can be controlled by controlling the warmer flow rate Qatf, and the engine coolant temperature Thw and the AT oil temperature Th can be controlled respectively. The temperature can be raised with an appropriate behavior. As a result, the engine 11 and the automatic transmission 22 can be warmed up in a well-balanced manner, and the warming up of the engine 11 and the automatic transmission 22 can be completed as early as possible. Can be effectively saved.
[0031]
<< Embodiment (2) >>
Next, Embodiment (2) of this invention is demonstrated using FIG. As described above, the lockup region of the automatic transmission 22 changes according to the operation mode and the gear position. For this reason, even if the warm-up of the automatic transmission 22 (the temperature increase of the AT oil temperature) is promoted under the same conditions and the lock-up control is permitted early, if the lock-up region changes, the execution frequency of the lock-up control also changes. Therefore, the fuel efficiency improvement effect due to the early warm-up of the automatic transmission 22 also varies depending on the lockup region.
[0032]
Therefore, in the present embodiment (2), when the warm-up control program shown in FIG. 7 is executed, when the lockup region is wide, that is, when the fuel efficiency improvement effect by the early warm-up of the automatic transmission 22 is large, the warmer The flow rate Qatf is increased to give priority to warm-up of the automatic transmission 22 (temperature increase of the AT oil temperature). On the other hand, when the lock-up region is narrow, that is, the fuel efficiency improvement effect due to early warm-up of the automatic transmission 22 is small. In some cases, the warmer flow rate Qatf is decreased to give priority to warming up of the engine 11 (temperature increase of the cooling water temperature).
[0033]
The warm-up control program shown in FIG. 7 is executed at a predetermined cycle after an ignition switch (not shown) is turned on, for example, and serves as warm-up control means in the claims. When this program is started, first, in step 201, it is determined whether or not the AT oil temperature Tho is equal to or lower than a predetermined determination value T1. This determination value T1 is set to, for example, the AT oil temperature used for the lockup control prohibition determination. When the AT oil temperature Th is equal to or lower than the determination value T1, the lockup control is prohibited.
[0034]
When it is determined that the AT oil temperature Tho is equal to or lower than the determination value T1, the process proceeds to step 202, and it is determined whether or not the currently set lockup region is wide. As a result, if it is determined that the lockup region is narrow, the process proceeds to step 203, where the warmer flow rate Qatf is set to the flow rate QM when the lockup region is narrow. The flow rate QM when the lockup region is narrow is set to a flow rate smaller than the flow rate QL when the lockup region described later is wide (QM <QL).
[0035]
When the AT oil temperature Tho is equal to or less than the determination value T1 and the lockup region is narrow, even if the automatic transmission 22 is warmed up (temperature rise of the AT oil temperature) and the lockup control is permitted early, the lockup control is performed. Since the execution frequency of the automatic transmission 22 is low, the fuel efficiency improvement effect due to the early warm-up of the automatic transmission 22 is small. In such a case, even if the AT oil temperature Tho is low, the warmer flow rate Qatf is reduced to give priority to warming up the engine 11 (temperature increase of the cooling water temperature), and the fuel efficiency improvement effect by early warming up of the engine 11 is greatly increased. To do.
[0036]
On the other hand, if it is determined in step 202 that the lockup region is wide, the process proceeds to step 204 where the warmer flow rate Qatf is set to the flow rate QL when the lockup region is wide. The flow rate QL when the lockup region is wide is set to be higher than the flow rate QM when the lockup region is narrow (QL> QM).
[0037]
When the AT oil temperature Tho is equal to or less than the determination value T1 and the lockup range is wide, if the automatic transmission 22 is warmed up (temperature rise of the AT oil temperature) and lockup control is permitted at an early stage, the lockup control Since the execution frequency is high, the fuel efficiency improvement effect due to the early warm-up of the automatic transmission 22 is great. In such a case, the warmer flow rate Qatf is increased to give priority to warming up of the automatic transmission 22 (temperature increase of the AT oil temperature), and the fuel efficiency improvement effect due to the early warming up of the automatic transmission 22 is increased.
[0038]
Thereafter, when it is determined in step 201 that the AT oil temperature Tho is higher than the determination value T1, the process proceeds to step 205, where the warmer flow rate Qatf is set to the minimum flow rate QS (QS <QM <QL).
[0039]
After the warmer flow rate Qatf is set in step 203, 204 or 205, the process proceeds to step 206, and the opening degree of the warmer flow rate adjustment valve 26 is controlled so as to become the set warmer flow rate Qatf.
[0040]
In the present embodiment (2) described above, when the lock-up region is wide, that is, when the effect of improving the fuel consumption by the early warm-up of the automatic transmission 22 is large, the warmer flow rate Qatf is increased to warm up the automatic transmission 22. On the other hand, when the lock-up region is narrow, that is, when the effect of improving the fuel efficiency due to the early warm-up of the automatic transmission 22 is small, the warmer flow rate Qatf is decreased to warm the engine 11. Since priority is given to the machine (temperature increase of the cooling water temperature), it is possible to obtain a stable fuel efficiency improvement effect that is not affected by the lockup region.
[0041]
In the present embodiment (2), the warmer flow rate Qatf is switched in two steps according to the lock-up region, but it may be switched in three steps or more or continuously (continuously).
[0042]
Further, the warmer flow rate Qatf may be set according to at least one of the engine coolant temperature Thw and the AT oil temperature Thho and the lockup region. In this way, it is possible to control the warmer flow rate Qatf in accordance with the lockup region while monitoring the engine coolant temperature Thw and the AT oil temperature Tho, thereby realizing warm-up control with a higher fuel efficiency improvement effect.
[0043]
In addition, the present invention may be implemented by appropriately changing the system configuration of the cooling water circulation circuit 16, the hot water circuit 20, etc. In short, the heat between the cooling water of the engine 11 and the hydraulic oil of the automatic transmission 22 is important. The present invention can be applied to any system provided with an ATF warmer 23 (heat exchanger) that performs replacement.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an entire system in an embodiment (1) of the present invention. FIG. 2 is a diagram conceptually showing a map of a lock-up area. FIG. 4 conceptually shows a map of warmer flow rate. FIG. 5 shows behaviors of engine coolant temperature and AT oil temperature in an execution example and a comparative example of warm-up control in the embodiment (1). Time chart (part 1)
FIG. 6 is a time chart (part 2) showing behaviors of engine coolant temperature and AT oil temperature in the execution example and comparative example of the warm-up control of the embodiment (1).
FIG. 7 is a flowchart showing the flow of processing of the warm-up control program according to the embodiment (2).
DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Mechanical water pump, 16 ... Cooling water circulation circuit, 19 ... Water temperature sensor, 20 ... Hot water circuit, 22 ... Automatic transmission, 23 ... ATF warmer (heat exchanger), 24 ... Operation Oil circulation circuit, 25 ... oil temperature sensor, 26 ... warmer flow rate adjustment valve, 27 ... ECU (warm-up control means).

Claims (2)

In a warm-up control device including a heat exchanger that performs heat exchange between cooling water of an internal combustion engine and hydraulic oil of an automatic transmission,
The operation region (hereinafter referred to as “lock-up region”) in which lock-up control is performed to directly connect the input side and output side of the torque converter of the automatic transmission is changed according to the operation mode and the gear position. And controlling the flow rate of the cooling water circulating to the heat exchanger in accordance with the lock-up region, whereby the temperature of the cooling water for the internal combustion engine (hereinafter referred to as “engine cooling water temperature”) and the hydraulic oil for the automatic transmission A warm-up control device comprising warm-up control means for controlling the temperature (hereinafter referred to as “AT oil temperature”). The warm-up control means controls a flow rate of cooling water circulating to the heat exchanger based on at least one of the engine cooling water temperature, the AT oil temperature, and the lockup region. Item 2. The warm-up control device according to Item 1 .

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