JP2003094984A - Automatic stopping and starting device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic stopping and starting device for an internal combustion engine, capable of improving fuel economy by automatic stop control of the internal combustion engine being mounted on a vehicle provided with a transmission constituted to hold a starting shift position using hydraulic oil. SOLUTION: An A/T (automatic transmission) 4 holds the starting shift position using the hydraulic oil pressurized by an oil pump 14 driven by the output of an engine 2. An A/T pump 22 is provided on a hydraulic circuit 18 parallel with a hydraulic circuit 16 including the oil pump 14. At the automatic stop of the engine 2, the A/T pump 22 is actuated by the drive of an electric motor 20 to hold the oil pressure of the hydraulic oil of the A/T 4. An ATF warmer 29 is provided on the hydraulic circuit 16 and also on the hydraulic circuit 18 including the A/T pump 22 to regulate the temperature of the hydraulic oil within a prescribed temperature range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal-combustion-engine automatic stop / start device for automatically stopping and automatically starting an on-vehicle internal combustion engine when a vehicle is stopped or started due to a signal waiting or the like.

[0002]

2. Description of the Related Art Conventionally, the internal combustion engine is automatically stopped when the vehicle is stopped, such as when waiting for a traffic light, when the vehicle is stopped, and is restarted when the vehicle starts, for the purpose of improving fuel efficiency when driving in urban areas with a high stopping rate. There is known an automatic stop / start device for an internal combustion engine.

[0003] On the other hand, an automatic transmission has been widely used which holds and switches each shift position by operating oil supplied from an engine-driven oil pump which uses an output of an on-vehicle internal combustion engine as a power source. In a vehicle equipped with such an automatic transmission, the transmission holds the shift position for starting by the hydraulic pressure of the pump while the vehicle is temporarily stopped, such as when waiting for a signal. This makes it possible to smoothly start the vehicle.

However, when the automatic stop / start device for an internal combustion engine is applied to a vehicle equipped with this type of automatic transmission, the oil pump stops operating as the internal combustion engine automatically stops. Therefore, the hydraulic pressure of the automatic transmission is lowered, and the automatic transmission cannot maintain the shift position for starting. When the internal combustion engine is restarted in such a state, the working oil pressure increases with the operation of the oil pump, but the shift position for starting cannot be held until the working oil pressure is sufficiently increased. However, there is a problem that the starting responsiveness decreases.

Therefore, conventionally, for example, Japanese Unexamined Patent Publication No. 8-1407 has been proposed.
As can be seen in Japanese Patent Laid-Open No. 6, there is proposed a device that holds a shift position for starting by using hydraulic oil whose pressure is adjusted by an electric oil pump during automatic stop of an internal combustion engine.

[0006]

By the way, the hydraulic oil has a property that its viscosity becomes high when its temperature is low.
Therefore, when the internal combustion engine is automatically stopped when the temperature of the hydraulic oil is low, the viscosity of the hydraulic oil is high, so that the load on the electric oil pump increases and the durability of the electric oil pump decreases. Therefore, when the temperature of the hydraulic oil is low, automatic stop and restart of the internal combustion engine are prohibited. However, since the automatic stop and restart of the internal combustion engine are prohibited, the fuel consumption improving effect is reduced.

Not only the vehicle equipped with the above automatic transmission, but also a vehicle equipped with a transmission that uses hydraulic oil to maintain the shift position for starting, the automatic stop of the internal combustion engine,
The actual situation associated with the restart is also common.

The present invention has been made in view of the above circumstances, and an object thereof is to mount an automatic stop control of an internal combustion engine on a vehicle equipped with a transmission that holds a shift position for starting using hydraulic oil. It is an object of the present invention to provide an automatic stop / start device for an internal combustion engine, which can improve fuel efficiency.

[0009]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. The invention described in claim 1 is a hydraulic transmission that holds a starting shift position by using hydraulic oil pressurized by an oil pump driven by an output of an internal combustion engine, and a hydraulic circuit including the oil pump. It is mounted on a vehicle equipped with a parallel hydraulic circuit that operates when the internal combustion engine is automatically stopped to maintain the hydraulic pressure of the hydraulic oil of the hydraulic transmission, and automatically stops and automatically starts the internal combustion engine. The automatic stop / start device includes a hydraulic circuit including the electric oil pump and oil temperature adjusting means for adjusting the temperature of the hydraulic oil within a predetermined temperature range.

According to the above construction, the oil pump operates to pressurize the hydraulic oil during operation of the internal combustion engine, and the starting shift position of the hydraulic transmission is maintained. When the internal combustion engine is stopped, the electric oil pump operates to maintain the hydraulic pressure of the hydraulic oil of the hydraulic transmission. At this time, when the temperature of the hydraulic oil is low, the temperature of the hydraulic oil is adjusted within the predetermined temperature range by the oil temperature adjusting means provided on the hydraulic circuit including the electric oil pump, so that the load on the electric oil pump is increased. Therefore, the durability of the electric oil pump can be prevented from decreasing.

According to a second aspect of the present invention, in the electric oil pump according to the first aspect, when the temperature of the hydraulic oil is equal to or lower than the predetermined temperature, the electric oil pump is operated during the operation of the internal combustion engine. The point is that it is also operated.

According to the above construction, when the temperature of the hydraulic oil of the hydraulic transmission is low, the oil pump is actuated by the output of the internal combustion engine and the electric oil pump is actuated so that the oil temperature adjusting means causes the hydraulic oil to operate. The temperature of can be warmed early. Therefore, it is possible to automatically stop and automatically start the internal combustion engine at an early stage.

The invention described in claim 3 is the same as claims 1 and 2.
In any one of the above items, the operating amount of the electric oil pump is variably set according to the temperature of the operating oil.

According to the above configuration, the operating amount of the electric oil pump is variably set according to the temperature of the operating oil,
The hydraulic oil temperature can be stabilized.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of an engine automatic stop and start device according to the present invention will be described below with reference to FIG.
-It demonstrates, referring FIG.

FIG. 1 shows an outline of the configuration of this embodiment.
In the present embodiment, the output of the engine 2 shown in FIG. 1 is an automatic transmission (hereinafter, referred to as A / T) including a torque converter.
Say. ) 4, the output is output from the output shaft 6 after a predetermined change. The A / T 4 is a portion that is provided with a plurality of planetary gear mechanisms and shifts the input driving force in five forward gears and one reverse gear, and maintains the engagement state of the gears of these planetary gear mechanisms. Switching of the engagement is performed by the hydraulic control unit 8.

As shown by the broken line in FIG. 1, the hydraulic control unit 8 uses an oil pan 10 and a hydraulic oil (hereinafter referred to as ATF) contained in the oil pan 10 as A.
And a valve body 12 that controls / T4. When the engine 2 is operating, the ATF in the oil pan 10 is pumped up and pressurized by the oil pump 14 provided in the A / T 4 and driven by the power of the engine 2 and supplied into the valve body 12. It
Since the ATF is pressurized in this way, it is possible to perform engagement control and switching control of the gears of the planetary gear mechanism using the hydraulic pressure of this ATF.

Further, as another means for pressurizing the ATF of the hydraulic control section 8, the hydraulic circuit 1 including the oil pump 14 is provided.
On the hydraulic circuit 18 provided in parallel with 6, the electric motor 2
A / T as an electric oil pump driven by 0
A pump 22 is provided. A / T pump 22 as an electric oil pump driven by electric motor 20
Is provided. In the 40th embodiment, the A / T pump 22 is operated during the automatic stop control of the engine 2. Then, the ATF in the oil pan 10 is pumped up and pressurized by the A / T pump 22 and supplied into the valve body 12. Since the ATF is pressurized in this way, the ATF hydraulic pressure of the A / T 4 is held, and the operating hydraulic pressure holds the shift position for starting the A / T 4.

The engine 2 also includes a forced circulation type cooling water circuit 24. The cooling water circuit 24 connects a water-cooled engine 2, a radiator 25, a bypass pipe 26, a thermostat 27, a water pump (W / P) 28, an ATF warmer 29 as an oil temperature adjusting means, a heater core 30 and the like in an annular shape. ing. And the engine 2
It has a water jacket (not shown) inside,
The cooling water cooled by the radiator 25 cools the outer peripheral portion of the cylinder, the cylinder head, and the like.

The radiator 25 exchanges heat between the cooling water, which has a high water temperature by absorbing engine exhaust heat while passing through the water jacket of the engine 2, and the air sent by a fan (not shown). Is a radiator for cooling. The bypass pipe 26 circulates the cooling water flowing out of the engine 2 from the radiator 25 and again
To form a bypass flow path.

The thermostat 27 is a thermo valve that automatically operates according to the temperature of the cooling water of the engine 2. This thermostat 27 is closed when the cooling water temperature of the engine 2 is low so that the cooling water circulates through the bypass pipe 26 without passing through the radiator 25, and the cooling water temperature of the engine 2 becomes high. At this time, the valve is opened so that the cooling water circulates to the radiator 25. W / P28 is
The cooling water is forcibly circulated by applying pressure.

The ATF warmer 29 is provided on the hydraulic circuit 16 including the oil pump 14 and the hydraulic circuit 18 including the A / T pump 22. The ATF warmer 29 exchanges heat between the cooling water and the ATF to make the ATF a proper oil. It is an oil cooler that cools to a warm temperature. The ATF warmer 29 is provided on the suction side and the discharge side of the oil pump 14 with respect to the hydraulic circuit 16 including the oil pump 14. Further, the ATF warmer 29 is provided on the discharge side of the A / T pump 22 with respect to the hydraulic circuit 18 including the A / T pump 22.
Therefore, if the ATF temperature is lower than the cooling water temperature, A
The TF is warmed by the cooling water temperature, and conversely, when the temperature of the ATF is higher than the cooling water temperature, the ATF is cooled by the cooling water temperature. The heater core 30 is a radiator that is arranged in a duct of an air conditioner (not shown), heats air passing through the duct, and is used for air conditioning of the vehicle interior.

FIG. 2 shows a hydraulic circuit 16 including the oil pump 14 and a hydraulic circuit 18 including an A / T pump 22. In the hydraulic circuit 16, the oil pump 14
An oil strainer 32 immersed in the ATF in the oil pan 10 is provided on the suction side of the oil pump 14 and
The discharge side is connected to the line pressure adjusting valve 33 in the valve body 12. An oil strainer 34 immersed in the ATF in the oil pan 10 is provided on the suction side of the A / T pump 22 in the hydraulic circuit 18.
The discharge side of the A / T pump 22 is connected to the ATF warmer 29 via a check valve 35. Further, the hydraulic circuit 18 is connected to the hydraulic circuit 16 on the downstream side of the ATF warmer 29 to connect the line pressure adjusting valve 33.
It is connected to the.

The engine 2 is controlled by an electronic control unit (hereinafter referred to as ECU) 40 including the hydraulic control unit 8 and the electric motor 20 for adjusting the engagement mode of the clutches and brakes in the A / T 4. To be done. This EC
In U40, in addition to performing various well-known controls related to vehicle traveling, automatic stop / start control of the engine in the present embodiment is performed based on the detection results of various sensors that detect the traveling state of the vehicle.

Here, the automatic stop / start control of the engine in this embodiment will be described. The control for automatically stopping the engine 2 is usually performed when the following conditions are satisfied under the condition that the ignition switch is turned on in order to automatically stop the engine 2 while waiting for a signal. That is, (a) the output signal of the vehicle speed sensor indicates the vehicle speed "0", (b) the output signal of the accelerator sensor indicates that the accelerator pedal is not depressed, and (c) the output signal of the brake sensor. Is a condition that indicates that the brake is pressed.

When the above conditions (a) to (c) are satisfied, the automatic stop control of the engine 2 is performed. However, if the engine 2 is automatically stopped, the oil pump 14 cannot pressurize the ATF. And
When the hydraulic pressure of the ATF in the hydraulic control unit 8 drops, the shift position for the next start cannot be maintained.

Therefore, in order to maintain the hydraulic pressure of the ATF in the hydraulic control unit 8 even when the engine 2 is automatically stopped, the pump driver 38 is stopped when the engine 2 is stopped.
By driving the electric motor 20 via the A / T pump 22, the ATF pressure is maintained. By holding the ATF hydraulic pressure in this manner, the shift position for starting can be maintained even when the engine is stopped. As a result, the next start can be favorably started.

By the way, when the temperature of the ATF in the hydraulic control section 8 is low, the ATF has a property of increasing the viscosity.
Therefore, if the internal combustion engine is automatically stopped when the temperature of the ATF is low, the viscosity of the ATF increases and the AT
Since the responsiveness of F becomes slower, the load on the A / T pump 22 may increase, and the A / T pump 22 may not be able to maintain the ATF hydraulic pressure sufficiently. As described above, if the sufficient hydraulic pressure of the ATF cannot be maintained when the engine 2 is automatically stopped, there is a possibility that the shift position for starting may not be maintained at the next starting.

Therefore, in this embodiment, when the temperature of the ATF is below a predetermined value, the automatic stop control of the engine is prohibited. However, in the present embodiment, the hydraulic circuit 18 including the A / T pump 22
Is provided in parallel with a hydraulic circuit 16 including the oil pump 14, and an ATF warmer 29 is provided on the hydraulic circuit 18. Therefore, even if the A / T pump 22 is operated to pressurize the ATF while the engine 2 is stopped, the ATF can be warmed by the ATF warmer 29, so that the load on the A / T pump 22 can be reduced. At the same time, the temperature of the ATF can be quickly brought within the predetermined temperature range. Therefore, in the present embodiment, the temperature of the ATF capable of controlling the automatic stop of the engine 2 is set to the ATF.
The warmer 29 can be set lower than in the case where the warmer 29 is not provided in the hydraulic circuit 18 including the A / T pump 22.

Further, the ECU 40 controls the operation amount of the A / T pump 22 when the engine 2 is automatically stopped, that is, the A / T
The discharge amount of ATF from the pump 22 is variably set according to its temperature. In the present embodiment, A
The discharge amount of the / T pump 22 is set to increase as the temperature of the ATF decreases, and decrease as the temperature of the ATF increases. When the temperature of the ATF is high, the viscosity of the ATF is low as opposed to when the temperature of the ATF is low. In such a case, if the operation amount of the A / T pump 22 is set to a large value, the ATF oil pressure is likely to rise and the A / T 4
The leakage of TF becomes large. However, in the present embodiment, when the temperature of the ATF is high, the operation amount of the A / T pump 22 is set to be small, so that useless operation of the A / T pump 22 is suppressed. Also, A / T pump 2
The electric power of the electric motor 20 that operates the motor 2 is generated by the output of the engine 2. Since the electric power can be reduced, the fuel consumption can be improved.

According to this embodiment described above, the following effects can be obtained. In the present embodiment, the hydraulic circuit 18 including the A / T pump 22 when the temperature of the ATF is low when the engine 2 is stopped
Since the ATF warmer 29 provided above adjusts the temperature of the ATF within a predetermined temperature range, the A / T pump 2
It is possible to suppress an increase in the load of No. 2 and suppress deterioration of durability of the A / T pump 22.

The discharge amount of the A / T pump 22 is A
Since the TF temperature is variably set so as to become larger and the ATF temperature becomes higher as the TF temperature becomes smaller, the hydraulic oil temperature can be stabilized.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is also A /
This was carried out on a vehicle equipped with T4. In order to avoid redundant description, the same elements as those described in FIGS. 1 and 2 are designated by the same reference numerals.

As shown in FIG. 4, in this embodiment, the AT
The F warmer 29 is the hydraulic circuit 18 including the A / T pump 22.
On the other hand, it is provided on the suction side and the discharge side of the A / T pump 22. FIG. 5 shows the hydraulic circuit 16 and the hydraulic circuit 18 of the present embodiment. In the hydraulic circuit 18, the A
The discharge side of the / T pump 22 is connected to the ATF warmer 29, and the hydraulic circuit 18 is connected to the hydraulic circuit 16 via a check valve 35 on the downstream side of the ATF warmer 29. In the hydraulic circuit 18, a relief valve 42 is provided between the ATF warmer 29 and the check valve 35. The valve opening pressure of the relief valve 42 is set to be equal to or lower than the minimum line pressure of the oil pump 14.

In the present embodiment configured as described above, the ECU 40 not only operates the A / T pump 22 while the engine 2 is automatically stopped, but also when the temperature of the ATF is low during the operation of the engine 2. M / A pump 22
Is designed to operate. In this case, engine 2
Discharged from the oil pump 14 operated by
The check valve 35 does not open because the hydraulic pressure of the TF becomes larger than the valve opening pressure of the relief valve 42. Therefore, the ATF discharged from the A / T pump 22 is returned to the oil pan 10 via the relief valve 42 after passing through the ATF warmer 29. Therefore, the ATF discharged from the A / T pump 22
Is warmed when passing through the ATF warmer 29, and is also warmed by the heat generated by the operation of the A / T pump 22, so that the ATF can be warmed early.

According to the present embodiment configured as described above, the A / T pump 22 is operated even when the engine 2 is operating and the ATF temperature is low, and the A / T pump 2 is operated.
The ATF discharged from the No. 2 is returned to the oil pan 10 via the relief valve 42 after passing through the ATF warmer 29. Therefore, A discharged from the A / T pump 22
The TF can be warmed by the ATF warmer 29 and also by the heat generated by the operation of the A / T pump 22, and the ATF can be warmed early. Therefore, the automatic stop and automatic start of the engine 2 can be performed at an early stage.

The embodiment is not limited to the above, but may be modified as follows. In each of the above embodiments, the hydraulic transmission is A / T4, but it may be a continuously variable transmission.

In each of the above embodiments, the ATF warmer 29 is provided on the discharge side of the A / T pump 22 in the hydraulic circuit 18, but the ATF warmer 29 is inserted only on the suction side of the A / T pump 22 in the hydraulic circuit 18. You may do it.

In each of the above embodiments, the ATF warmer 29 that adjusts the temperature of the ATF within the predetermined temperature range based on the temperature of the engine cooling water is used, but the ATF warmer may be an electric type.

Next, other technical ideas that can be understood from the above-described embodiments will be described below. (A) The automatic stop / start device for an internal combustion engine according to any one of claims 1 and 2, wherein a relief valve is provided on a hydraulic circuit of the electric oil pump.

(B) An automatic stop / start device for an internal combustion engine according to any one of claims 1 to 3 and (a), wherein the hydraulic transmission is an automatic transmission.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an engine automatic stop / start device according to a first embodiment.

FIG. 2 is a hydraulic circuit diagram of the ATF according to the first embodiment.

FIG. 3 is an explanatory view showing a temperature transition of ATF when an ATF warmer is used.

FIG. 4 is a schematic diagram showing an engine automatic stop / start device according to a second embodiment.

FIG. 5 is a hydraulic circuit diagram of the ATF according to the second embodiment.

[Explanation of symbols]

2 ... Engine, 4 ... Automatic transmission (A / T), 14 ... Oil pump, 16, 18 ... Hydraulic circuit, 20 ... Electric motor,
22 ... A / T pump (electric oil pump), 29 ... AT
F warmer (oil temperature adjusting means), 42 ... Relief valve.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 29/02 321 F02D 29/02 321A F16H 57/02 302 F16H 57/02 302D 57/04 57/04 G (72) Inventor Hideo Tomomatsu 1 Toyota-cho, Toyota-shi, Aichi F-term in Toyota Motor Co., Ltd. (reference) 3D041 AA21 AC09 AC15 AD10 AD30 AD41 AD51 AE30 3G092 AC03 CA02 DG07 EA08 FA30 HF08Z HF11 HF19Z HF21Z HF26Z 3G0922 A05 DA06 DB05 DB09 DB15 EB06 EC01 FA11 3J063 AA02 AB12 AC04 BA20 BB50 XH32 XJ02 XJ03

Claims (3)

[Claims] 1. A hydraulic transmission that holds a shift position for starting using hydraulic oil pressurized by an oil pump driven by the output of an internal combustion engine, and a hydraulic circuit parallel to a hydraulic circuit including the oil pump. An automatic stop start for automatically stopping and automatically starting the internal combustion engine mounted on a vehicle equipped with an electric oil pump which operates when the internal combustion engine is automatically stopped and holds the hydraulic pressure of the hydraulic oil of the hydraulic transmission An automatic stop / start apparatus for an internal combustion engine, comprising an oil temperature adjusting means for adjusting the temperature of the hydraulic oil within a predetermined temperature range on a hydraulic circuit including the electric oil pump. 2. The electric oil pump according to claim 1, wherein when the temperature of the hydraulic oil is equal to or lower than the predetermined temperature, the electric oil pump is operated even when the oil pump is in operation accompanying the operation of the internal combustion engine. Automatic stop starter. 3. The automatic stop / start device for an internal combustion engine according to claim 1, wherein the operating amount of the electric oil pump is variably set according to the temperature of the operating oil.