JP4106792B2 - Idle stop vehicle - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an idle stop vehicle that automatically stops an engine when the vehicle is stopped.
[0002]
[Prior art]
There is known an idle stop vehicle in which fuel consumption is reduced and exhaust gas is reduced by automatically stopping and restarting the engine by waiting for a signal at an intersection.
[0003]
In such an idle stop vehicle, when the engine stops, the oil pump driven by the engine also stops and no hydraulic pressure is supplied to the transmission, so that the oil pump operates when the engine is restarted. As a result, the engine oil pressure was delayed and the engine was blown out due to the clutch engagement delay.
[0004]
In order to prevent this, Japanese Patent Application Laid-Open No. 8-14076 discloses that an accumulator or an electric hydraulic pump is provided as a transmission hydraulic pressure holding and supplying means, and the hydraulic pressure is continuously supplied to the automatic transmission even when the engine is stopped. A technique for preventing the engine from being blown due to a delay is disclosed.
[0005]
[Problems to be solved by the invention]
However, although this conventional technique can prevent the engine from being blown away, it is configured to continue to supply hydraulic pressure to the transmission clutch and valve group of the automatic transmission even when the engine is stopped. In view of the pressure drop due to leakage from the transmission clutch and valve group, an increase in the size of the device was inevitable.
[0006]
Further, when an electric hydraulic pump is used as the transmission hydraulic pressure holding and supplying means, it is more expensive than an accumulator, and also consumes electric power, which may reduce the original effect of suppressing fuel consumption.
[0007]
The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to improve the mountability of the apparatus in a vehicle while preventing idling when the engine is restarted in an idle stopped vehicle.
[0008]
[Means for solving problems]
A first invention includes a hydraulic pressure source driven by an engine, and transmission hydraulic pressure holding and supplying means for holding the hydraulic pressure from the hydraulic pressure source and supplying the hydraulic pressure to the transmission, under predetermined operating conditions. In an idle stop vehicle that automatically stops and restarts the engine, Start-up Means for supplying the hydraulic pressure held in the transmission hydraulic pressure holding and supplying means to the transmission, and means for starting up the rotation of the engine after a predetermined time has elapsed since the supply of hydraulic pressure from the transmission hydraulic pressure holding and supplying means started. And a means for detecting the hydraulic pressure and oil temperature of the transmission hydraulic pressure holding and supplying means, and the predetermined time is set based on the detected hydraulic pressure and oil temperature of the transmission hydraulic pressure holding and supplying means. It is characterized by that.
[0009]
[0010]
[0011]
First 2 The invention of 1st invention And a means for detecting the hydraulic pressure of the transmission hydraulic pressure holding and supplying means and a means for prohibiting automatic stop of the engine when the detected hydraulic pressure of the transmission hydraulic pressure holding and supplying means is equal to or lower than a predetermined pressure. To do.
[0012]
First 3 The invention of the 2 In the present invention, the predetermined pressure is set to a value obtained by adding a pressure drop due to leakage from the transmission hydraulic pressure holding supply means to a hydraulic pressure value capable of transmitting torque input to the transmission when the engine is restarted. And
[0013]
First 4 The invention of the 3 In accordance with the present invention, there is provided means for detecting the hydraulic pressure and oil temperature of the transmission hydraulic pressure holding and supplying means, and based on the hydraulic pressure and oil temperature of the hydraulic pressure holding and supplying means in which the pressure drop due to leakage from the transmission hydraulic pressure holding and supplying means is detected. It is characterized by being operated.
[0014]
First 5 The invention of 1st invention Means for detecting the hydraulic pressure of the transmission hydraulic pressure holding supply means, and means for automatically restarting the engine when the detected hydraulic pressure of the transmission hydraulic pressure holding supply means drops below a predetermined pressure during automatic engine stop It is characterized by comprising.
[0015]
First 6 The invention of the 5 The invention is characterized in that a hydraulic pressure value capable of transmitting torque input to the transmission when the engine is restarted is set as the predetermined pressure.
[0016]
First 7 The invention of the first to the second 6 The invention is characterized in that the supply destination of the hydraulic pressure from the transmission hydraulic pressure holding and supplying means is limited to elements necessary for starting the vehicle in the transmission.
[0017]
[Action and effect]
According to the first aspect of the invention, the engine is automatically restarted by releasing the brake pedal while the driver is idle. Start-up When this is done, first, hydraulic pressure supply is started from the transmission hydraulic pressure holding and supplying means to the transmission. Then, the engine rotation is started after a predetermined time has elapsed since the supply of hydraulic pressure to the transmission was started.
[0018]
Accordingly, the hydraulic pressure has already spread to the transmission at the time when the engine rotation rises, and there is no poor engagement of the power transmission element due to a delay in the hydraulic pressure rise, and it is possible to prevent a sense of incongruity at the time of re-starting such as engine blow-off. . Further, since it is not necessary to continue to supply hydraulic pressure to the transmission even when the engine is stopped as in the prior art, the apparatus can be reduced in size and the mountability on the vehicle is not impaired.
[0019]
Also, the time from when the hydraulic pressure supply to the transmission starts until the hydraulic pressure reaches the power transmission element of the transmission varies depending on the hydraulic pressure and oil temperature of the transmission hydraulic pressure holding and supplying means. , Since the time until the engine speed rises is set based on the hydraulic pressure and oil temperature of the transmission hydraulic pressure holding and supplying means, the engine speed can be raised at an appropriate time.
[0020]
[0021]
The second 2 The second 3 According to this invention, even when the vehicle is stopped due to a signal or the like, the hydraulic pressure of the transmission hydraulic pressure holding and supplying means is below a predetermined pressure, for example, engine Start-up When the hydraulic pressure value that can sometimes transmit torque input to the transmission is equal to or less than the value obtained by adding the pressure drop due to leakage from the transmission hydraulic pressure holding and supplying means, automatic engine stop is prohibited. As a result, it is possible to avoid a situation in which the engine is automatically stopped in a state where sufficient hydraulic pressure is not stored in the transmission hydraulic pressure holding and supplying means, and sufficient hydraulic pressure is not supplied to the transmission when the engine is restarted.
[0022]
The pressure drop due to leakage from the transmission hydraulic pressure holding and supplying means varies depending on the hydraulic pressure and the oil temperature. 4 According to the invention, since the pressure drop due to the leakage is set based on the hydraulic pressure and the oil temperature of the transmission hydraulic pressure holding and supplying means, the hydraulic pressure required at the time of restart can be accurately obtained.
[0023]
The second 5 The second 6 According to the invention, even when idling is stopped, the hydraulic pressure of the transmission hydraulic pressure holding and supplying means is equal to or lower than a predetermined pressure, for example, equal to or lower than a hydraulic pressure value at which the input torque to the transmission can be transmitted at the target engine speed at startup. If this happens, the engine is automatically started. As a result, it is possible to prevent the hydraulic pressure stored in the transmission hydraulic pressure holding and supplying means from decreasing below the hydraulic pressure required to engage the power transmission element at the time of restart.
[0024]
The second 7 According to the invention, the supply destination of the hydraulic pressure from the transmission hydraulic pressure holding and supplying means is limited to elements necessary for restarting the engine in the transmission and starting the vehicle, so that the leakage flow rate during idling stop can be minimized. As a result, the transmission hydraulic pressure holding and supplying means can be reduced, and the mounting property to the vehicle is improved.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0026]
First, the configuration of an idle stop vehicle and its hydraulic control circuit to which the present invention is applied will be described with reference to FIGS. 1 to 4, and then the engine performed in the idle stop vehicle with reference to FIGS. 5 to 12. The contents of the automatic stop / start control will be described.
[0027]
FIG. 1 shows a schematic configuration of an idle stop vehicle to which the present invention is applied, and FIGS. 2 and 3 show a schematic configuration of a hydraulic control circuit 101 of the continuously variable transmission 17.
[0028]
This idle stop vehicle includes an engine 1 and a continuously variable transmission 17, and the controller 7 controls these based on signals from various sensors (not shown). In particular, when a predetermined condition is satisfied when the vehicle is stopped such as waiting for a signal, the controller 7 automatically stops and restarts the engine 1.
[0029]
A torque converter 10 and a forward / reverse switching mechanism 11 are interposed between the engine 1 and the continuously variable transmission 17. A hydraulic pump 14 is connected to the input shaft of the torque converter 10 as a hydraulic source, and the hydraulic pressure generated by the hydraulic pump 14 is supplied to the hydraulic control circuit 101. The forward / reverse switching mechanism 11 is mainly composed of a planetary gear mechanism 19, and switches the rotation direction of the input shaft 15 by selectively engaging the forward clutch 12 and the reverse clutch 13 driven by the hydraulic control circuit 101. Can do.
[0030]
Here, the continuously variable transmission 17 is a so-called V-belt continuously variable transmission that includes a primary pulley 16, a secondary pulley 26, and a V-belt 24 wound around them.
[0031]
As shown in FIG. 2, the primary pulley 16 has a fixed conical plate 18 that rotates integrally with the input shaft 15, and is disposed so as to face the fixed conical plate 18 to form a V-shaped pulley groove and to the primary pulley cylinder chamber 20. The movable conical plate 22 is configured to be displaced in the axial direction of the input shaft 15 by acting hydraulic pressure. Similarly, the secondary pulley 26 is provided with a fixed conical plate 30 that rotates integrally with the driven shaft 28 and a hydraulic pressure acting on the secondary pulley cylinder chamber 32 while forming a V-shaped pulley groove so as to be opposed to the fixed conical plate 30. Accordingly, the movable conical plate 34 can be displaced in the axial direction of the driven shaft 28.
[0032]
Returning to FIG. 1, the drive gear 46 that meshes with the idler gear 48 is fixed to the driven shaft 28, and the pinion gear 54 provided on the idler shaft 52 of the idler gear 48 meshes with the final gear 55. The final gear 55 drives the drive shaft 57 via the differential device 56.
[0033]
During the transmission of the driving force as described above, the hydraulic pressure in the primary pulley cylinder chamber 20 and the secondary pulley cylinder chamber 32 is controlled to displace the movable conical plate 22 of the primary pulley 16 and the movable conical plate 34 of the secondary pulley 26 in the axial direction. If the contact radius with the V-belt 24 is changed, the transmission ratio of the continuously variable transmission 17 can be changed.
[0034]
For example, if the width of the pulley groove of the primary pulley 16 is increased, the contact radius of the V belt 24 on the secondary pulley 26 side becomes relatively large, and a large gear ratio (Low side) is obtained. Conversely, if the width of the pulley groove of the primary pulley 16 is reduced, a small gear ratio (Hi side) can be obtained.
[0035]
Such control of the pulley groove width of the primary pulley 16 and the secondary pulley 26 is performed by controlling the hydraulic pressure to the primary pulley cylinder chamber 20 and the secondary pulley cylinder chamber 32. Specifically, the controller 7 controls the step motor 64 of the hydraulic control circuit 101 shown in FIG. 2, and the step motor 64 drives the speed change control valve 63 in response to a command from the controller 7, and the primary pulley. The hydraulic pressure supplied to the 16 cylinder chambers 20 and the cylinder chamber 32 of the secondary pulley 26 is adjusted to control the gear ratio of the continuously variable transmission 17.
[0036]
The line pressure solenoid 74 is duty ratio controlled by the controller 7 and drives the line pressure control valve 60 via the pilot valve 61 and the pressure modifier valve 62. Then, the hydraulic pressure from the hydraulic pump 14 driven by the engine 1 is set to a predetermined line pressure and supplied to the line pressure circuit 40, and the predetermined hydraulic pressure is supplied to the clutch pressure circuit 41 of the line pressure control valve 60. The cylinder chamber 32 of the secondary pulley 26 communicates with the line pressure circuit 40.
[0037]
Further, as shown in FIG. 3, the clutch pressure circuit 41 connected downstream of the line pressure control valve 60 is connected to a port 107b of the manual valve 107 that responds to the shift lever 81 via a check valve 108. The hydraulic pressure is supplied to the forward clutch 12 or the reverse clutch 13 via the port 107a or the port 107b according to the position of the spool 107s of the manual valve 107.
[0038]
In other words, if the shift lever 81 is in the forward position such as the D range, the ports 107b and 107a communicate with each other, the hydraulic pressure of the clutch pressure circuit 41 is supplied to the forward clutch 12 and fastened, while the port 107c communicates with the drain port 107d. Then, the reverse clutch 13 is released. If the shift lever 81 is in the reverse position of the R range, the port 107b and the port 107c communicate with each other, and the hydraulic pressure of the clutch pressure circuit 41 is supplied to the reverse clutch 13 and tightened, while the port 107a is connected to the drain side (in the drawing). The forward clutch is released in communication with the upper X).
[0039]
The above configuration is substantially the same as the hydraulic control circuit disclosed in Japanese Patent Application Laid-Open No. 9-242855 by the present applicant, but in this embodiment, the hydraulic pressure from the hydraulic pump 14 is further maintained and the controller 7 A transmission hydraulic pressure holding and supplying circuit 9 is provided which can supply the hydraulic pressure held in response to the hydraulic pressure supply command to the power transmission element (forward clutch 12 or reverse clutch 13) of the continuously variable transmission 17. A hydraulic pressure supply circuit 42 for guiding the hydraulic pressure from the transmission hydraulic pressure holding and supplying circuit 9 is connected between the check valve 108 and the manual valve 107 of the clutch pressure circuit 41 via a check valve 109.
[0040]
The check valve 108 restricts the hydraulic pressure from the hydraulic pressure supply circuit 42 from flowing toward the line pressure control valve 60, and guides the hydraulic pressure from the transmission hydraulic pressure holding and supply circuit 9 only to the manual valve 107. The stop valve 109 is for restricting the hydraulic pressure from the line pressure control valve 60 from flowing into the transmission hydraulic pressure holding and supplying circuit 9 during operation of the engine 1.
[0041]
The configuration of the transmission hydraulic pressure holding and supplying circuit 9 will be described in detail with reference to FIG.
[0042]
As shown in FIG. 4, in the line pressure circuit 40 of the hydraulic control circuit 101, a shutoff valve 120 is interposed between the secondary pulley cylinder chamber 32 and the hydraulic pump 14, and the shutoff valve 120 and the secondary pulley cylinder chamber 32 are connected to each other. Between them, a hydraulic pressure supply circuit 42 is disposed via a check valve 121.
[0043]
Since the continuously variable transmission 17 transmits power by the contact friction force between the primary pulley 16, the secondary pulley 26 and the V belt 24 as described above, the secondary pulley cylinder chamber 32 when the engine 1 is stopped and no line pressure is generated. If the hydraulic pressure of the engine is released, the driving force cannot be transmitted until the hydraulic pressure in the secondary pulley cylinder chamber 32 increases when the engine is restarted.
[0044]
For this reason, when the line pressure falls below a predetermined value, the secondary pulley hydraulic chamber 32 and the hydraulic pump 14 are shut off by the shut-off valve 120, and when the hydraulic pressure in the secondary pulley cylinder chamber 32 falls below the set pressure of the pressure reducing valve 117, the check valve. The valve 121 is opened, and the hydraulic pressure is supplied from the transmission hydraulic pressure holding and supplying circuit 9 to the secondary pulley cylinder chamber 32.
[0045]
The transmission hydraulic pressure holding supply circuit 9 is provided with an accumulator 115 via a pressure accumulation control valve 112 and a check valve 114, and the hydraulic pressure held thereby is supplied to the pressure reducing valve 117. . A downstream side of the pressure reducing valve 117 communicates with the hydraulic pressure supply circuit 42.
[0046]
The pressure accumulation control valve 112 communicates when the hydraulic pressure (line pressure) from the hydraulic pump 14 is a predetermined value, for example, below the accumulator maximum pressure, and supplies hydraulic pressure to the accumulator 115 via the check valve 114, while the line pressure is predetermined. When the value is exceeded, the hydraulic pressure from the hydraulic pump to the accumulator 115 is cut off, and the energy loss for pressure accumulation is minimized.
[0047]
Further, the pressure reducing valve 117 reduces the hydraulic pressure supplied to the hydraulic pressure supply circuit 42 to a predetermined hydraulic pressure (for example, about 0.2 MPa) that is just before the forward clutch 12 or the reverse clutch 13 is engaged.
[0048]
A relief valve 113, a hydraulic pressure sensor 116, and an oil temperature sensor 111 are provided between the check valve 114 and the pressure reducing valve 117. The relief valve 113 operates so that the hydraulic pressure between the check valve 114 and the pressure reducing valve 117 does not exceed a predetermined value, for example, the accumulator maximum pressure. The pressure sensor 116 and the oil temperature sensor 111 detect the oil pressure and the oil temperature of the accumulator 115, and are used for engine automatic stop / start control described later.
[0049]
In the present embodiment, the pressure reducing valve 117 is further interposed between the check valve 114 and the pressure reducing valve 117 in order to raise the hydraulic pressure of the power transmission element of the continuously variable transmission 17 prior to the start of engine rotation when the engine is restarted. A pilot pressure circuit 119 communicating with the spring chamber side is disposed, and a three-way solenoid valve 118 controlled by the controller 7 is interposed in the pilot pressure circuit 119.
[0050]
The three-way solenoid valve 118 switches whether to supply the hydraulic pressure downstream of the check valve 114 to the spring chamber side of the pressure reducing valve 117 or to set the drain state in accordance with a command from the controller 7. When the hydraulic pressure downstream of 114 is guided to the spring chamber side, the check valve 117 becomes a simple switching valve, and the set pressure of the relief valve 113 or the hydraulic pressure of the accumulator 115 is transmitted via the hydraulic pressure supply circuit 42 to the power transmission element (forward clutch). 12 etc.). Note that when the spring chamber side is in the drain state, the hydraulic pressure reduced according to the set pressure of the spring is supplied to the hydraulic pressure supply circuit 42.
[0051]
Subsequently, referring to FIG. 5 to FIG. 12, the contents of the engine automatic stop / start control performed in the idling stop vehicle having the above-described configuration are the processes of engine restart, engine stop permission determination, engine restart determination. The process will be described separately.
[0052]
First, processing that is performed when the engine is restarted, that is, when the engine is restarted from an idle stop state will be described.
[0053]
FIG. 5 shows the processing contents at that time. First, in step S11, it is determined whether or not an engine automatic start command has been issued. Here, the engine automatic start command is a command issued when a predetermined condition (such as brake pedal ON → OFF) is satisfied during idle stop. If it is determined that the engine automatic start command has been issued, the process proceeds to step S12. Otherwise, the process remains in step S11. At this point, only the engine automatic start command has been issued, Start-up do not do.
[0054]
In step S12, based on the outputs from the pressure sensor 116 and the oil temperature sensor 111, the hydraulic pressure and oil temperature of the hydraulic circuit section between the check valve 114 and the pressure reducing valve 117 of the transmission hydraulic pressure holding supply circuit 9 that is the supply source are determined. Detected.
[0055]
In step S13, a standby time until the rotation of the engine 1 is started is set with reference to map data as shown in FIG. 6 based on the hydraulic pressure and oil temperature of the supply source detected in step S12. Since it is considered that the hydraulic pressure reaches the supply destination in a shorter time as the hydraulic pressure and the oil temperature are higher, the standby time is set shorter as the hydraulic pressure is higher and the oil temperature is higher.
[0056]
In step S14, a hydraulic pressure supply command is issued to the transmission hydraulic pressure holding and supplying circuit 9, and supply of hydraulic pressure to the power transmission elements (such as the forward clutch 12) of the automatic transmission 17 is started. Specifically, the three-way solenoid valve 118 is driven, and the set pressure of the relief valve 113 or the hydraulic pressure of the accumulator 115 is supplied to the hydraulic pressure supply circuit 42.
[0057]
In step S15, measurement of the elapsed time t after the hydraulic pressure supply command is issued is started, and in step S16, it is determined whether or not the elapsed time t is equal to or longer than the standby time set in step S13. And when standby time passes, it progresses to step S17, and stays at step S16 otherwise.
[0058]
In step S17, an engine rotation start command is issued. Specifically, an engine starting motor, for example, a starter motor is energized, and the engine 1 is Start-up Is done.
[0059]
Therefore, by processing the above flow, when an engine automatic start command is issued, for example, when the driver cancels the depression of the brake pedal during idling stop, the transmission hydraulic pressure holding and supplying circuit 9 first starts the continuously variable transmission. The hydraulic pressure supply is started at 17. Then, after a predetermined time has elapsed since the start of the hydraulic pressure supply, a command for starting up the rotation of the engine 1 is issued. Since the hydraulic pressure of the continuously variable transmission 17 is raised in advance as described above, when the rotation start command for the engine 1 is issued, it is already sufficient for a power transmission element (such as the forward clutch 12) required for starting. Therefore, the engine 1 is not blown away due to poor clutch engagement.
[0060]
Unlike the prior art, the hydraulic pressure is not continuously supplied to the transmission even when the engine 1 is stopped, and the supply destination of the hydraulic pressure is limited to the forward clutch 12 or the like necessary for starting the vehicle. Leakage flow can be minimized. Thereby, pressure accumulation elements, such as the accumulator 115, can be reduced in size, and the mounting property to a vehicle improves.
[0061]
Furthermore, although the response time of the hydraulic pressure supply changes depending on the hydraulic pressure of the supply source and the oil temperature, in this embodiment, since the standby time is set using these as parameters, the shortest time is set as the standby time until the engine rotation is started up. Can be set. As a result, the delay in starting up the engine rotation is kept to the minimum necessary, and the starting feeling can be improved.
[0062]
FIG. 7 shows how the supply destination hydraulic pressure and the engine rotation change when the engine is restarted. As described above, since the engine rotation start command is issued after a predetermined time has elapsed since the hydraulic pressure supply was started, engine blow-off due to poor clutch engagement is reliably prevented.
[0063]
In this case, the engine rotation start command is issued after a predetermined time has elapsed since the hydraulic pressure supply command is issued. However, as shown in FIG. 8, the hydraulic pressure of the supply destination is detected (step S23), and it exceeds the predetermined hydraulic pressure. For example, engine re Start-up The engine rotation start-up command may be issued after the hydraulic pressure that can be transmitted without slipping the clutch sometimes exceeds the torque input to the automatic transmission 17 (steps S24 and S25).
[0064]
FIG. 9 shows how the supply destination hydraulic pressure and the engine speed change when the engine is restarted in this case. Thus, by issuing the engine rotation start command after the supply hydraulic pressure has actually increased to a predetermined value, it is possible to reliably prevent the engine rotation from starting in a state of poor clutch engagement.
[0065]
Next, an engine stop permission determination process, that is, a determination process for determining whether or not an idle stop is permitted when the vehicle stops due to a signal or the like will be described.
[0066]
FIG. 10 shows the details of the engine stop permission determination process. First, in step S31, it is determined whether or not the engine is rotating (during normal operation). If it is determined that the engine is rotating, the process proceeds to step S32. Otherwise, the process remains in step S31.
[0067]
In step S32, it is determined whether or not an engine stop condition, for example, a vehicle speed of zero and a brake pedal ON condition is satisfied. If the condition is satisfied, the process proceeds to step S33, and otherwise the process remains in step S32.
[0068]
In step S33, the hydraulic pressure and the oil temperature of the hydraulic circuit section between the check valve 114 and the pressure reducing valve 117 of the transmission hydraulic pressure holding supply circuit 9 that is the supply source are detected, and in step S34, the hydraulic pressure detected in step S33 is detected. The pressure drop due to leakage is calculated based on the oil temperature. Here, the pressure drop due to leakage is calculated by referring to map data as shown in FIG. 11, and a larger value is calculated as the pressure at the supply source is higher and the oil temperature at the supply source is higher.
[0069]
In step S35, whether or not the supply hydraulic pressure exceeds a predetermined pressure, for example, a value obtained by adding the pressure drop due to leakage to the hydraulic pressure required to transmit the torque input to the continuously variable transmission 17 when the engine is restarted. If it does not exceed, the routine proceeds to step S36 where the automatic engine stop is prohibited.
[0070]
Therefore, by processing this flow, even if the vehicle is stopped due to a signal waiting or the like, the automatic engine stop is prohibited if the hydraulic pressure necessary for restarting is not secured. Further, in order to perform restart without causing a clutch engagement failure, the necessary hydraulic pressure is set in consideration of the hydraulic pressure drop due to leakage that occurs during the stop period. If the pressure drop due to leakage is large, the required hydraulic pressure is set. Is set to a large value. As a result, it is possible to prevent the engine stoppage from being stopped in a state where sufficient hydraulic pressure is not stored in the transmission hydraulic pressure holding and supplying circuit 9 as the supply source, and the engagement of the power transmission element due to insufficient hydraulic pressure when the engine is restarted Defects can be prevented.
[0071]
Furthermore, the pressure drop due to leakage differs depending on the oil pressure and oil temperature of the supply source, but the oil temperature has changed because the pressure drop due to leakage is calculated with reference to the map data using the supply oil pressure and oil temperature as parameters. Even if it is the case, the best judgment can be made.
[0072]
Here, as the required oil pressure at the time of restart, a value obtained by adding the pressure drop due to leakage to the oil pressure required to transmit the torque input to the continuously variable transmission 17 at the time of engine restart is set. The same effect can be obtained by simplifying the above and setting the maximum pressure of the accumulator.
[0073]
Next, engine restart determination processing, that is, determination processing for determining whether or not to restart the engine when idling is stopped will be described.
[0074]
FIG. 12 is a flowchart showing the contents of the engine restart determination process. First, in step S41, it is determined whether or not the engine is stopped. If the engine is stopped, the process proceeds to step S42.
[0075]
In step S42, it is determined whether or not an engine restart condition, for example, a brake pedal ON → OFF condition is satisfied. If the condition is satisfied, the process proceeds to step S44 and an engine automatic start command is issued. If the condition is not satisfied, the process proceeds to step S43.
[0076]
In step S43, the hydraulic pressure in the hydraulic circuit between the check valve 114 and the pressure reducing valve 117, which is the supply source, is equal to or lower than a predetermined pressure, for example, a hydraulic pressure that can transmit torque input to the transmission according to the target engine speed at startup It is determined whether the pressure is equal to or lower than the predetermined value. If the pressure is equal to or lower than the predetermined pressure, the process proceeds to step S44 and an engine automatic start command is issued. Note that the median value of the maximum pressure and the minimum pressure of the accumulator may be set as the predetermined pressure.
[0077]
Therefore, by processing this flow, when the hydraulic pressure of the transmission hydraulic pressure holding and supplying circuit 9 decreases to near the hydraulic pressure required at the time of restart due to leakage or the like while the engine is stopped, other restart conditions are satisfied. Even if not, an engine automatic start command is issued. As a result, poor engagement of the power transmission element at the time of engine restart due to insufficient supply source pressure can be prevented, and the reliability of the idle stopped vehicle can be improved.
[0078]
When the engine 1 is automatically started due to a decrease in hydraulic pressure, the engine 1 is started regardless of the driver's intention to start. Therefore, a configuration may be adopted in which attention is urged by a buzzer or a lamp before starting the engine.
[0079]
The embodiment of the present invention has been described above. However, the scope of the present invention is not limited to this, and the present invention can be widely applied to an idle stop vehicle including a transmission hydraulic pressure holding and supplying means. .
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an idle stop vehicle to which the present invention is applied.
FIG. 2 is a schematic configuration diagram of a hydraulic control circuit of a continuously variable transmission.
FIG. 3 is a schematic configuration diagram of a hydraulic control circuit of the continuously variable transmission.
FIG. 4 is a schematic configuration diagram of a transmission hydraulic pressure holding and supplying circuit.
FIG. 5 is a flowchart for explaining processing at the time of engine restart.
FIG. 6 is a map for setting a standby time until the engine speed is raised based on the hydraulic pressure of the supply source and the oil temperature.
FIG. 7 is a timing chart showing changes in supply destination hydraulic pressure and engine speed when the engine is restarted.
FIG. 8 is a flowchart for explaining another example of processing at the time of engine restart.
FIG. 9 is a timing chart showing changes in supply destination hydraulic pressure and engine speed when the engine is restarted in that case.
FIG. 10 is a flowchart for explaining engine stop permission determination processing;
FIG. 11 is a map for calculating a pressure drop due to leakage based on the oil pressure of the supply source and the oil temperature.
FIG. 12 is a flowchart for explaining engine restart determination processing;
[Explanation of symbols]
1 engine
7 Controller
9 Transmission hydraulic pressure retention and supply circuit
12 Forward clutch
13 Reverse clutch
17 Continuously variable transmission
42 Hydraulic supply circuit
101 Hydraulic control circuit
107 Manual valve
111 Oil temperature sensor
116 Pressure sensor
115 Accumulator

Claims (7)

An oil pressure source driven by the engine and a transmission oil pressure holding and supplying means capable of holding the oil pressure from the oil pressure source and supplying the oil pressure to the transmission are provided. In an idle stop vehicle that restarts,
It means for supplying hydraulic pressure and held in the engine restart at the transmission oil pressure holding supplying means to the transmission,
Means for starting up the rotation of the engine after a predetermined time has elapsed since the start of the hydraulic pressure supply from the transmission hydraulic pressure holding and supplying means;
Means for detecting oil pressure and oil temperature of the transmission oil pressure holding and supplying means,
The idle stop vehicle , wherein the predetermined time is set based on the detected hydraulic pressure and oil temperature of the transmission hydraulic pressure holding and supplying means . It means for detecting the hydraulic pressure of the front Symbol transmission hydraulic retention supply means,
Means for prohibiting automatic stop of the engine when the detected hydraulic pressure of the transmission hydraulic pressure holding supply means is equal to or lower than a predetermined pressure;
The idle stop vehicle according to claim 1, further comprising: The predetermined pressure is set to a value obtained by adding a pressure drop due to leakage from the transmission hydraulic pressure holding and supplying means to a hydraulic pressure value capable of transmitting torque input to the transmission when the engine is restarted. The idle stop vehicle according to claim 2 . Means for detecting oil pressure and oil temperature of the transmission oil pressure holding and supplying means,
4. The idle stopped vehicle according to claim 3 , wherein a pressure drop due to leakage from the transmission hydraulic pressure holding supply means is calculated based on the detected hydraulic pressure and oil temperature of the hydraulic pressure holding supply means. It means for detecting the hydraulic pressure of the front Symbol transmission hydraulic retention supply means,
During automatic engine stop, according to claim 1, characterized by comprising, a means for automatically restarting the engine when the oil pressure of the detected transmission hydraulic retention supply means drops below a predetermined pressure Idle stop vehicle. 6. The idle stopped vehicle according to claim 5 , wherein the predetermined pressure is set to a hydraulic pressure value capable of transmitting torque input to the transmission when the engine is restarted. Idle described the hydraulic pressure supply destination from the transmission oil pressure holding supplying means, to any one of claims 1 to 6, characterized by being configured as limited to the elements required vehicle launch of the transmission machine Stop vehicle.

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