Automatic transmission, control method for automatic transmission, and program

Abstract

The present application improves the acceleration performance at the time of vehicle start while suppressing the deterioration of fuel consumption rate. The automatic transmission is set to a first gear ratio at the time of start with accelerator pedal opening degree less than a prescribed opening degree, and is set to a second gear ratio on the low side than the first gear ratio at the time of start with accelerator pedal opening degree equal to or more than the prescribed opening degree.

Description

Technical Field

[0001] This invention relates to an automatic transmission, a control method for the automatic transmission, and a program for the automatic transmission. Background Technology

[0002] Patent Document 1 discloses a vehicle control device that, when there is an idle stop determination and the continuously variable transmission (CVT) (automatic transmission) is not at its maximum gear ratio (lowest gear ratio), releases the forward clutch before the engine stops and releases the hydraulic pressure from the primary pulley, returning the CVT to its maximum gear ratio. In this control device, at the maximum gear ratio, the movable pulley of the primary pulley abuts against a limiter. Therefore, through the reaction force from the limiter, the thrust generated by the secondary pulley acts as an auxiliary force on the primary pulley via belt tension. Thus, even if the hydraulic pressure supply to the primary pulley is delayed, belt slippage can be suppressed.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-230131

[0006] The problem that the invention aims to solve

[0007] However, if the automatic transmission is at its maximum gear ratio, the engine speed will be higher when the vehicle starts, which may worsen fuel consumption. On the other hand, to improve the vehicle's acceleration performance when starting, it is necessary to drive at the maximum gear ratio. Summary of the Invention

[0008] The present invention was made in view of the above-mentioned problems, and its purpose is to suppress the deterioration of fuel consumption rate while improving the acceleration performance of the vehicle at start-up.

[0009] According to one aspect of the present invention, the automatic transmission is set to a first gear ratio when starting with the accelerator pedal opening less than a predetermined opening, and is set to a second gear ratio on the lower side than the first gear ratio when starting with the accelerator pedal opening greater than the predetermined opening.

[0010] According to another aspect of the invention, an automatic transmission that shifts to the parking gear ratio before changing from a driving state to a parking state is set to a gear ratio higher than the parking gear ratio when starting with the accelerator pedal opening less than a predetermined opening, and is set to the parking gear ratio when starting with the accelerator pedal opening greater than the predetermined opening.

[0011] According to another aspect of the invention, an automatic transmission that shifts to the parking gear ratio before changing from a driving state to a parking state is set to the parking gear ratio when starting with the accelerator pedal opening less than a predetermined opening, and is set to a gear ratio on the lower gear side than the parking gear ratio when starting with the accelerator pedal opening greater than the predetermined opening.

[0012] Invention Effects

[0013] In the above method, when the accelerator pedal opening is greater than or equal to a specified opening, the vehicle starts with a gear ratio closer to the lower gear side than when the accelerator pedal opening is less than the specified opening, thus achieving acceleration from a standstill that corresponds to the driver's acceleration request. On the other hand, when the accelerator pedal opening is less than the specified opening, the vehicle starts with a gear ratio closer to the higher gear side than when the accelerator pedal opening is greater than or equal to the specified opening, thus suppressing the deterioration of fuel consumption. Therefore, it is possible to suppress the deterioration of fuel consumption while improving the vehicle's acceleration performance during start-up. Attached Figure Description

[0014] Figure 1 This is a schematic structural diagram of a vehicle equipped with an automatic transmission according to an embodiment of the present invention.

[0015] Figure 2 It is a flowchart representing the gear shift control process performed by the transmission controller during start-up.

[0016] Figure 3 This is a flowchart illustrating the gear shift control process of shifting to the higher gear ratio after the gear ratio is set to the second gear ratio.

[0017] Figure 4 It is a timing diagram illustrating the gear ratio when starting with the accelerator pedal opening less than the specified opening, and then shifting to the higher gear after a specified time.

[0018] Figure 5 This is a timing diagram illustrating the gear ratio shift to the higher gear when the pulley surface of the belt reaches a specified value after starting with the accelerator pedal opening less than the specified opening.

[0019] Figure 6 It is a timing diagram illustrating the gear ratio of shifting to the higher gear side based on the upshift indication of the automatic transmission after starting with the accelerator pedal opening less than the specified opening.

[0020] Figure 7 It is a timing diagram illustrating the gear ratio of shifting to the higher gear side based on the upshift indication returned by the accelerator pedal after starting with the accelerator pedal opening less than the specified opening. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, a gear ratio of large is referred to as low gear, and a gear ratio of small is referred to as high gear. Furthermore, shifting the gear ratio towards a lower gear is called downshifting, and shifting the gear ratio towards a higher gear is called upshifting.

[0022] Figure 1 This is a schematic structural diagram of a vehicle 100 equipped with an automatic transmission 20 according to an embodiment of the present invention. Figure 1 As shown, the vehicle 100 includes: an engine 10 as a drive source, an automatic transmission 20, an engine controller 30, and a transmission controller 40.

[0023] The automatic transmission 20 includes: a hydraulic torque converter 2, a forward / reverse switching mechanism as a power transmission mechanism 3, a transmission mechanism 4 as a gear shifting mechanism, an oil pressure control circuit 5, and an oil pump 6.

[0024] In vehicle 100, the rotation generated by engine 10 is transmitted to drive wheel 50 via hydraulic torque converter 2, forward / reverse switching mechanism 3, transmission mechanism 4, gear set 7, and differential gear device 8.

[0025] A lock-up clutch 2a is provided in the torque converter 2. When the lock-up clutch 2a is engaged, the input shaft 2b, which is the input element of the torque converter 2, and the output shaft 2c, which is the output element, are directly connected, and the input shaft 2b and the output shaft 2c rotate at the same speed. Therefore, when the lock-up clutch 2a is engaged, the rotation of the output shaft 10a of the engine 10 is directly transmitted from the output shaft 2c of the torque converter 2 to the forward / reverse switching mechanism 3.

[0026] The forward / reverse switching mechanism 3 uses a double-pinion planetary gear set as its main component. Its sun gear is connected to the engine 10 via the hydraulic torque converter 2, and the planetary gear carrier is connected to the input shaft 4d (primary pulley 4a) of the transmission mechanism 4. The forward / reverse switching mechanism 3 also includes a forward clutch 3a that directly connects the sun gear and the planetary gear carrier of the double-pinion planetary gear set, and a reverse brake 3b with a fixed gear ring. When the forward clutch 3a is engaged, the input rotation from the engine 10 via the hydraulic torque converter 2 is transmitted to the primary pulley 4a at a constant speed. When the reverse brake 3b is engaged, the input rotation from the engine 10 via the hydraulic torque converter 2 is reversed and decelerated before being transmitted to the primary pulley 4a.

[0027] The transmission mechanism 4 is a continuously variable transmission (CVT) mechanism that changes the speed of the rotation of the engine 10 transmitted to the input shaft 4d and transmits it from the output shaft 4e to the drive wheel 50. The transmission mechanism 4 includes: a primary pulley 4a disposed on the engine 10 side in the power transmission path; a secondary pulley 4b disposed on the drive wheel 50 side; and a belt 4c, which is a ring-shaped component, wound around the primary pulley 4a and the secondary pulley 4b.

[0028] In the transmission mechanism 4, the contact radius between each pulley 4a, 4b and the belt 4c is changed by controlling the oil pressure supplied to the primary pulley 4a and the secondary pulley 4b, thereby changing the transmission ratio. The belt 4c abuts against the pulley surfaces 4f and 4g of each pulley 4a, 4b, transmitting power between the primary pulley 4a and the secondary pulley 4b.

[0029] A limiter 4h is provided on the secondary pulley 4b. This limiter 4h specifies the lowest gear ratio R on the lowest gear side of the transmission mechanism 4. ML Alternatively, a limiter can be installed on the primary pulley 4a, or on both pulleys 4a and 4b.

[0030] Oil pump 6 is a mechanical oil pump that is driven by a portion of the rotation of engine 10 and the power of engine 10. Oil discharged from oil pump 6 is supplied to oil pressure control circuit 5.

[0031] The hydraulic control circuit 5 includes: a regulating valve 5a that adjusts the pressure of the working oil supplied from the oil pump 6 and generates the necessary oil pressure; a primary solenoid valve 5b that adjusts the oil pressure supplied to the primary pulley 4a; a secondary solenoid valve 5c that adjusts the oil pressure supplied to the secondary pulley 4b; a lock-up solenoid valve 5d that adjusts the oil pressure supplied to the lock-up clutch 2a; a selection solenoid valve 5e that adjusts the oil pressure supplied to the forward clutch 3a and the reverse brake 3b; and a manual valve 5f that switches the supply path of the oil pressure supplied to the forward clutch 3a and the reverse brake 3b.

[0032] The hydraulic control circuit 5 supplies adjusted hydraulic pressure to various parts of the hydraulic torque converter 2, forward / reverse switching mechanism 3, and transmission mechanism 4 based on the control signal from the transmission controller 40.

[0033] The engine controller 30 is composed of a microcomputer equipped with a CPU, RAM, ROM, input / output interfaces, etc. The engine controller 30 performs various processes by reading and executing programs stored in the ROM through the CPU. The engine controller 30 can also be composed of multiple microcomputers.

[0034] The engine controller 30 controls the engine speed and torque of the engine 10 based on signals from various sensors that detect the state of various parts of the vehicle 100.

[0035] The transmission controller 40 is a microcomputer equipped with a CPU, RAM, ROM, input / output interfaces, etc., and is communicatively connected to the engine controller 30. The transmission controller 40 reads and executes programs stored in the ROM through the CPU to perform various processes. The transmission controller 40 can also be composed of multiple microcomputers. Alternatively, the transmission controller 40 and the engine controller 30 can be combined into a single controller.

[0036] The transmission controller 40 controls the engagement status of the lock-up clutch 2a, the gear ratio of the transmission mechanism 4, the engagement status of the forward clutch 3a and the reverse brake 3b, etc., based on signals from various sensors that detect the status of various parts of the vehicle 100.

[0037] The transmission controller 40 receives the following signals: an accelerator pedal opening sensor 61 that detects the accelerator pedal opening APO; a brake hydraulic pressure sensor 62 that detects the brake hydraulic pressure BRP corresponding to the brake pedal operation; a circuit breaker 64 that detects the position of the shift device 63; a turbine speed sensor 65 that detects the rotational speed Nt of the output shaft 2c of the torque converter 2; a primary speed sensor 66 that detects the rotational speed Np of the input shaft 4d (primary pulley 4a) of the transmission mechanism 4; a secondary speed sensor 67 that detects the rotational speed Ns of the output shaft 4e (secondary pulley 4b) of the transmission mechanism 4; a primary hydraulic pressure sensor 68 that detects the primary hydraulic pressure Pp supplied to the primary pulley 4a; and a secondary hydraulic pressure sensor 69 that detects the secondary hydraulic pressure Ps supplied to the secondary pulley 4b.

[0038] Next, refer to Figure 2 and Figure 3 The processing of speed control by the transmission controller 40 will be explained. Figure 2 This is a flowchart illustrating the gear shift control process performed by the transmission controller 40 during startup. Figure 3 This is a flowchart illustrating the transmission control process when shifting to a higher gear ratio after the gear has been set to the second gear ratio R2. The transmission control process is executed by the transmission controller 40 at regular intervals.

[0039] First, refer to Figure 2 The processing of the gear shift control during start-up by the transmission controller 40 will be explained. The gear shift control during start-up is executed when the driver depresses the accelerator pedal to start the vehicle at 100.

[0040] Here, "starting" includes not only the situation where the vehicle speed is zero and the accelerator pedal is pressed to switch to the driving state, but also the situation where the vehicle speed is very slow (crawl driving state) after the brake pedal is released and the accelerator pedal is pressed to switch to the normal driving state.

[0041] In step S11, the transmission controller 40 determines whether the accelerator pedal opening APO at start-up is greater than or equal to a predetermined opening. If it is determined in step S11 that the accelerator pedal opening APO is less than the predetermined opening, the process proceeds to step S12. On the other hand, if it is determined in step S11 that the accelerator pedal opening APO is greater than or equal to the predetermined opening, the process proceeds to step S13.

[0042] In step S12, since the accelerator pedal opening APO is relatively small and the driver's acceleration request is not large, the transmission controller 40 sets the gear ratio of the automatic transmission 20 to the first gear ratio R1.

[0043] In step S13, since the accelerator pedal opening APO is relatively large and the driver's acceleration request is large, the transmission controller 40 sets the gear ratio of the automatic transmission 20 to the second gear ratio R2, which is lower than the first gear ratio R1.

[0044] Here, before the vehicle 100 decelerates from a driving state to a stationary state, the automatic transmission 20 is shifted to the parking gear ratio R. S The parking gear ratio R S R is the lowest gear ratio on the lowest gear side within the range of gear ratios used in normal transmission control. L In contrast, in the automatic transmission 20, when the vehicle starts moving at 100, the lowest gear ratio R on the lowest gear side of the transmission mechanism 4, as defined by the limiter 4h, is used. ML The lowest gear ratio R ML It is a gear ratio that is further down the range of gear ratios than those used in normal gear control.

[0045] When the automatic transmission 20 starts with the accelerator pedal opening APO less than the specified opening, it is still set as the parking gear ratio R. S Low gear ratio R L (First gear ratio R1), when starting from a position above the specified accelerator pedal opening (APO), the gear shift is lower than the gear ratio R. L The lowest gear ratio R on the lower gear side ML (Second gear ratio R2). That is, when the driver's acceleration request is large, the automatic transmission 20, which has a pair of pulleys 4a and 4b, utilizes the lowest gear ratio R on the lowest gear side, which is structurally obtained. ML Let's get started.

[0046] Thus, when the accelerator pedal opening APO is above the specified opening, due to the lowest gear ratio R... ML It can start, thus responding to the driver's acceleration requests. On the other hand, when the accelerator pedal opening APO is less than the specified opening, it can still accelerate at a gear ratio lower than the lowest gear R. ML The lower gear ratio R on the higher gear side L This allows for better acceleration from a standstill, thus preventing a decline in fuel consumption. Therefore, it not only helps to suppress the deterioration of fuel consumption but also improves the vehicle's acceleration performance when starting from 100 km / h.

[0047] Alternatively, the automatic transmission 20 can be shifted to the lowest gear ratio R before the vehicle 100 decelerates from a moving state to a stop. ML That is, the gear ratio R when parking. S It can also be the lowest gear ratio R. ML .

[0048] In this situation, when the automatic transmission 20 starts with the accelerator pedal opening APO less than the specified opening, it is shifted to a ratio that serves as the parking shift ratio R. S The lowest gear ratio R ML The gear ratio on the higher gear side (first gear ratio R1) is still set to the lowest gear ratio R when starting from a position above the specified accelerator pedal opening (APO). ML (Second gear ratio R2).

[0049] In the same situation, it can also suppress the deterioration of fuel consumption rate and improve the vehicle's acceleration performance when starting from 100 km / h.

[0050] Next, refer to Figure 3 The process of shifting to a higher gear ratio after the automatic transmission 20 is set to the second gear ratio R2 is explained. After the automatic transmission 20 is set to the second gear ratio R2 and the vehicle starts moving at 100 km / h, shifting to a higher gear ratio is performed.

[0051] In the automatic transmission 20, a gear ratio further down the gear range than that used in normal transmission control is utilized, namely the lowest gear gear ratio R. ML If the lowest gear ratio R is used continuously for an extended period of time... ML This increases the surface pressure acting on the contact surfaces 4f and 4g that come into contact with belt 4c, causing the temperature of pulley surfaces 4f and 4g to rise. Additionally, if the lowest gear ratio R is continuously used... ML When driving, the engine speed remains high, which risks worsening fuel consumption.

[0052] Therefore, in response to the driver's acceleration request, the transmission controller 40 shifts the automatic transmission 20 to a gear ratio higher than the second gear ratio R2. Preferably, the automatic transmission 20 is shifted to a first gear ratio R1 or a gear ratio higher than the first gear ratio R1.

[0053] In step S21, the transmission controller 40 determines whether a predetermined time has elapsed since the vehicle 100 started. This predetermined time is, for example, set to approximately a few seconds. If it is determined in step S21 that the predetermined time has elapsed, the process proceeds to step S25, where the automatic transmission 20 is shifted to a gear ratio that is higher than the second gear ratio R2.

[0054] In this way, after the automatic transmission 20 is set to the second gear ratio R2 and starts moving, after a predetermined time (the "yes" determination in step S21), it shifts to a gear ratio higher than the second gear ratio R2 (step S25). Thus, after a predetermined time has elapsed following the driver's acceleration request when the vehicle 100 starts, the automatic transmission 20 shifts to a higher gear ratio, thereby suppressing the deterioration of fuel consumption.

[0055] On the other hand, in step S21, if it is determined that the prescribed time has not elapsed, the process proceeds to step S22.

[0056] In step S22, the transmission controller 40 determines whether the temperatures of the pulley surfaces 4f and 4g of pulleys 4a and 4b have reached or exceeded a predetermined value. Here, the temperatures of the pulley surfaces 4f and 4g are estimated, for example, by the following formula.

[0057] Tp=ΔT+Tlub=(Qin-Qout) / C×(t1-t2)+Tlub

[0058] At this point, Tp is the temperature of pulley surfaces 4f and 4g [°C], ΔT is the temperature rise [°C], Tlub is the lubricating oil temperature (oil pan temperature) [°C], (t1-t2) is the unit time [sec], Qin is the heat generation rate [J / sec], Qout is the heat dissipation rate [J / sec], and C is the heat capacity [J / °C]. Qin ≒ "thrust of primary pulley 4a" × "slippage", meaning "slippage" ∝ "rotation speed of primary pulley 4a". Qout is calculated from "chain lubrication flow rate" and "rotation speed of primary pulley 4a". "Chain lubrication flow rate" is calculated from "engine 10 rotation speed", "main pressure (pipeline pressure)", "oil temperature", and "engagement / release (ON / OFF) of lock-up clutch 2a". The heat capacity C is calculated from "lubrication flow rate" and "rotation speed of primary pulley 4a".

[0059] If it is determined in step S22 that the temperature of the pulley surfaces 4f and 4g has reached or exceeded the specified value, the process proceeds to step S25, where the automatic transmission 20 is shifted to a gear ratio that is higher than the second gear ratio R2.

[0060] Thus, after the automatic transmission 20 is set to the second gear ratio R2 and starts moving, even if a predetermined time has elapsed (determined as "No" in step S21), if the temperature of the pulley surfaces 4f and 4g of pulleys 4a and 4b reaches a predetermined value or higher (determined as "Yes" in step S22), the transmission shifts to a gear ratio higher than the second gear ratio R2 (step S25). Therefore, in response to the driver's acceleration request when the vehicle 100 starts, when the temperature of the pulley surfaces 4f and 4g of pulleys 4a and 4b reaches a predetermined value or higher, the transmission shifts to a higher gear ratio, thereby reducing the load on pulleys 4a and 4b.

[0061] On the other hand, if it is determined in step S22 that the temperature of pulley surfaces 4f and 4g has not reached the specified value, the process proceeds to step S23.

[0062] In step S23, the transmission controller 40 determines whether the temperature of the lubricating oil has reached or exceeded a specified value. If it is determined in step S23 that the temperature of the lubricating oil has reached or exceeded the specified value, the process proceeds to step S25, where the automatic transmission 20 is shifted to a gear ratio that is higher than the second gear ratio R2.

[0063] Thus, after the automatic transmission 20 is set to the second gear ratio R2 and starts moving, even if a predetermined time has elapsed (determined as "No" in step S21), if the temperature of the lubricating oil reaches a predetermined value or higher (determined as "Yes" in step S23), the transmission shifts to a gear ratio higher than the second gear ratio R2 (step S25). Therefore, in response to the driver's acceleration request when the vehicle 100 starts, when the temperature of the lubricating oil reaches a predetermined value or higher, the automatic transmission 20 shifts to a higher gear ratio, thereby reducing the load on pulleys 4a and 4b.

[0064] On the other hand, if it is determined in step S23 that the temperature of the lubricating oil has not reached the specified value, the process proceeds to step S24.

[0065] In step S24, the transmission controller 40 determines whether there is an upshift indication. The upshift indication is either an automatic transmission-based upshift indication when the vehicle 100 accelerates to a certain speed, or an accelerator return-based upshift indication when the driver returns the accelerator pedal. If an upshift indication is determined in step S24, the process proceeds to step S25, where the automatic transmission 20 is shifted to a gear ratio higher than the second gear ratio R2.

[0066] Thus, after the automatic transmission 20 is set to the second gear ratio R2 and starts, even if a predetermined time has elapsed (determined as "No" in step S21), when there is an upshift indication (determined as "Yes" in step S24), it is shifted to a gear ratio that is higher than the second gear ratio R2 (step S25).

[0067] On the other hand, in step S24, if it is determined that there is no upshift indication, the process returns to step S21 to repeat the determination.

[0068] Next, refer to Figures 4 to 7 The starting speed control of the transmission controller 40 is explained in detail.

[0069] First, refer to Figure 4 This explains the situation where, after starting with the accelerator pedal opening APO less than the specified opening, the gear ratio shifts to the higher gear side after a specified time. Figure 4 It is a timing diagram illustrating the gear ratio when starting with the accelerator pedal opening APO less than the specified opening, and then shifting to the higher gear side after a specified time.

[0070] At time T11, the driver depresses the accelerator pedal. This increases engine torque. At this time, since the accelerator pedal opening APO is above the specified opening, the indicated pressure (SEC indicated pressure) of the oil pressure supplied to the secondary pulley 4b increases. Consequently, the target gear ratio of the automatic transmission 20 changes from the parking gear ratio R... S Low gear ratio R L (First gear ratio R1) is set to be higher than the lower gear ratio R. L The lowest gear ratio R on the lower gear side ML (Second gear ratio R2). Additionally, the timer sets the target gear ratio to the lowest gear ratio R. ML The time elapsed since the beginning is used to keep track of time.

[0071] At time T12, since a predetermined time has elapsed since time T11, the automatic transmission 20 is shifted to a gear ratio higher than the second gear ratio R2. Therefore, by shifting to a higher gear ratio after a predetermined time has elapsed following the driver's acceleration request when the vehicle starts at 100 km / h, the deterioration of fuel consumption can be suppressed.

[0072] Next, refer to Figure 5 This document explains the situation where, after starting with the accelerator pedal opening APO less than the specified opening, the temperature of the pulley surfaces 4f and 4g of pulleys 4a and 4b reaches a specified value or higher, resulting in a shift to the higher gear ratio. Figure 5This is a timing diagram illustrating the gear ratio shift to the higher gear side when the pulley surfaces 4f and 4g of pulleys 4a and 4b reach a specified value after starting with the accelerator pedal opening APO less than the specified opening.

[0073] At time T21, the driver depresses the accelerator pedal. This increases engine torque. At this time, since the accelerator pedal opening APO is above the specified opening, the indicated pressure (SEC indicated pressure) of the oil pressure supplied to the secondary pulley 4b increases. Consequently, the target gear ratio of the automatic transmission 20 changes from the parking gear ratio R... S Low gear ratio R L (First gear ratio R1) is set to be higher than the lower gear ratio R. L The lowest gear ratio R on the lower gear side ML (Second gear ratio R2). Additionally, the timer sets the target gear ratio to the lowest gear ratio R. ML The time elapsed since the beginning is used to keep track of time.

[0074] At time T22, although no prescribed time has elapsed since time T21, the automatic transmission 20 is shifted to a higher gear ratio than the second gear ratio R2 because the temperatures of the pulley surfaces 4f and 4g of pulleys 4a and 4b have reached or exceeded the prescribed values. This reduces the load on pulleys 4a and 4b.

[0075] In addition, if the temperature of the lubricating oil, rather than the temperature of the pulley surfaces 4f and 4g, reaches a specified value, the same speed control is performed, which can reduce the load on pulleys 4a and 4b.

[0076] Next, refer to Figure 6 This explains the situation where, after starting with the accelerator pedal opening APO less than the specified opening, the gear ratio is changed to the higher gear side based on the upshift indication of the automatic transmission. Figure 6 This is a timing diagram illustrating the gear ratios of shifting to the higher gear side via the upshift indicator based on the automatic transmission after starting with the accelerator pedal opening APO less than the specified opening.

[0077] At time T31, the driver depresses the accelerator pedal. This increases engine torque. At this time, since the accelerator pedal opening APO is above the specified opening, the indicated pressure (SEC indicated pressure) of the oil pressure supplied to the secondary pulley 4b increases. Consequently, the target gear ratio of the automatic transmission 20 changes from the parking gear ratio R... S Low gear ratio R L (First gear ratio R1) is set to be higher than the lower gear ratio R. L The lowest gear ratio R on the lower gear side ML (Second gear ratio R2). Additionally, the timer sets the target gear ratio to the lowest gear ratio R. MLThe time elapsed since the beginning is used to keep track of time.

[0078] At time T32, when the vehicle accelerates to a certain speed, the automatic transmission 20 is shifted to a gear ratio higher than the second gear ratio R2 by means of an upshift instruction based on the automatic transmission.

[0079] Thus, after the automatic transmission 20 is set to the second gear ratio R2 and starts moving, even if a predetermined time has elapsed, when there is an upshift instruction based on the automatic transmission, the automatic transmission 20 is shifted to a gear ratio that is higher than the second gear ratio R2.

[0080] Next, refer to Figure 7 This explains the situation where, after starting with the accelerator pedal opening APO less than the specified opening, the gear ratio is shifted to the higher gear side based on the upshift indication returned by the accelerator. Figure 7 This is a timing diagram illustrating the gear ratios used to shift to a higher gear after starting with the accelerator pedal opening APO less than the specified opening, based on the upshift indication returned by the accelerator.

[0081] At time T41, the driver depresses the accelerator pedal. This increases engine torque. At this time, since the accelerator pedal opening APO is above the specified opening, the indicated pressure (SEC indicated pressure) of the oil pressure supplied to the secondary pulley 4b increases. Consequently, the target gear ratio of the automatic transmission 20 changes from the parking gear ratio R... S Low gear ratio R L (First gear ratio R1) is set to be higher than the lower gear ratio R. L The lowest gear ratio R on the lower gear side ML (Second gear ratio R2). Additionally, the timer sets the target gear ratio to the lowest gear ratio R. ML The time elapsed since the beginning is used to keep track of time.

[0082] At time T42, when the driver returns the depressed accelerator pedal, the automatic transmission 20 is shifted to a gear ratio higher than the second gear ratio R2 by an upshift instruction based on the accelerator return.

[0083] Thus, after the automatic transmission 20 is set to the second gear ratio R2 and starts moving, even if a predetermined time has elapsed, when there is an upshift instruction based on accelerator return, the automatic transmission 20 is shifted to a gear ratio that is higher than the second gear ratio R2.

[0084] The structure and effects of the above-described implementation method are summarized and explained.

[0085] The automatic transmission 20 is set to the first gear ratio R1 when starting with the accelerator pedal opening APO less than a specified opening, and is set to the second gear ratio R2, which is lower than the first gear ratio R1, when starting with the accelerator pedal opening APO greater than the specified opening.

[0086] In addition, in the control method of the automatic transmission 20, when the accelerator pedal opening APO starts at a level less than a predetermined opening, the automatic transmission 20 is set to a first gear ratio R1, and when the accelerator pedal opening APO starts at a level greater than a predetermined opening, the automatic transmission 20 is set to a second gear ratio R2 that is lower than the first gear ratio R1.

[0087] Based on these structures, when the accelerator pedal opening APO is greater than or equal to a predetermined opening, the automatic transmission 20 is set to a gear ratio closer to the lower gear side than when the opening is less than the predetermined opening, thus enabling acceleration from a standstill that corresponds to the driver's acceleration request. On the other hand, when the accelerator pedal opening APO is less than the predetermined opening, the automatic transmission 20 is set to a gear ratio closer to the higher gear side than when the opening is greater than the predetermined opening, thus suppressing the deterioration of fuel consumption. Therefore, it is possible to suppress the deterioration of fuel consumption while improving the vehicle's acceleration performance at 100 km / h.

[0088] Additionally, the automatic transmission 20 includes: a transmission mechanism 4 having a pair of pulleys 4a and 4b respectively disposed on the engine 10 side and the drive wheel 50 side, and a belt 4c wound between the pair of pulleys 4a and 4b; and a limiter 4h that defines the lowest gear ratio R on the lowest gear side of the transmission mechanism 4. ML The second gear ratio R2 is the lowest gear ratio R. ML .

[0089] According to this structure, the automatic transmission 20, which has a pair of pulleys 4a and 4b, can start at the lowest gear ratio obtained in the structure, thus improving the acceleration performance of the vehicle 100 when starting.

[0090] In addition, after the automatic transmission 20 is set to the second gear ratio R2 and starts, it is shifted to a gear ratio that is higher than the second gear ratio R2 after a specified time.

[0091] According to this structure, after a specified time has elapsed following the driver's acceleration request when the vehicle starts at 100 km / h, the gear ratio is shifted to the higher gear side, thus suppressing the deterioration of fuel consumption rate.

[0092] In addition, after the automatic transmission 20 is set to the second gear ratio R2 and starts, when the temperature of the pulley surfaces 4f and 4g of a pair of pulleys 4a and 4b reaches a specified value or above, it is shifted to a gear ratio that is higher than the second gear ratio R2.

[0093] According to this structure, after responding to the driver's acceleration request when the vehicle starts at 100 km / h, if the temperature of the pulley surfaces 4f and 4g of pulleys 4a and 4b reaches a specified level, the gear ratio is changed to the higher gear side, thus reducing the load on pulleys 4a and 4b.

[0094] In addition, when the automatic transmission 20 is set to the second gear ratio R2 and starts, when the temperature of the lubricating oil reaches a specified value or above, it is shifted to a gear ratio that is higher than the second gear ratio R2.

[0095] According to this structure, after responding to the driver's acceleration request when the vehicle starts at 100 km / h, if the temperature of the lubricating oil reaches a specified level, the gear ratio is changed to the higher gear side, thus reducing the load on pulleys 4a and 4b.

[0096] Additionally, the gear ratio R for parking when shifting from a driving state to a stationary state. S The automatic transmission 20 is set to a gear ratio R that is less than the parking gear ratio when starting with the accelerator pedal opening APO less than a specified opening. S The gear ratio on the higher gear side is set as the parking gear ratio R when starting from a position above the accelerator pedal opening (APO). S .

[0097] Additionally, the gear ratio R for parking when shifting from a driving state to a stationary state. S The control method of the automatic transmission 20 is as follows: when starting with the accelerator pedal opening APO less than a specified opening, the automatic transmission 20 is set to a gear ratio R that is less than the parking gear ratio. S When the gear ratio on the higher gear side is above the specified opening of the accelerator pedal (APO), the automatic transmission 20 is set to the parking gear ratio (R). S .

[0098] Based on these structures, when the accelerator pedal opening APO is less than the specified opening, the gear shift is performed using a gear ratio R that is less than the stopping ratio. S Starting with the higher gear ratio allows for acceleration to meet the driver's demands. Additionally, when the accelerator pedal opening (APO) is less than the specified opening, it can be shifted to the parking gear ratio (R). S Starting up can help curb the deterioration of fuel consumption rates.

[0099] Additionally, the gear ratio R for parking when shifting from a driving state to a stationary state. SThe automatic transmission 20 is set to a parking gear ratio R when starting with the accelerator pedal opening APO less than a specified opening. S When starting from a position greater than the specified accelerator pedal opening (APO), the gear ratio R is set to be higher than the stop gear ratio. S The gear ratio on the lower gear side.

[0100] Additionally, the gear ratio R for parking when shifting from a driving state to a stationary state. S The control method of the automatic transmission 20 is as follows: when starting with the accelerator pedal opening APO less than a specified opening, the automatic transmission 20 is set to the parking gear ratio R. S When starting from a position greater than the specified accelerator pedal opening (APO), the automatic transmission 20 is set to a gear ratio R that is less than the parking gear ratio. S The gear ratio on the lower gear side.

[0101] Based on these structures, when the accelerator pedal opening (APO) is greater than or equal to a specified opening, starting with a gear ratio closer to the lower gear side than when the accelerator pedal opening is less than the specified opening can meet the driver's acceleration request. Furthermore, when the accelerator pedal opening (APO) is less than the specified opening, starting with a gear ratio closer to the higher gear side than when the accelerator pedal opening is greater than the specified opening can suppress the deterioration of fuel consumption.

[0102] The embodiments of the present invention have been described above. However, the above embodiments are merely one example of the application of the present invention, and the technical scope of the present invention is not limited to the specific structure of the above embodiments.

[0103] The various programs executed by the transmission controller 40 may be, for example, programs stored on a non-transitory recording medium such as a CD-ROM.

[0104] Symbol Explanation

[0105] 20: Automatic transmission

[0106] 4: Transmission mechanism

[0107] 4a: Primary pulley (pulley)

[0108] 4b: Secondary pulley (pulley)

[0109] 4f: Pulley surface

[0110] 4g: Pulley surface

[0111] 4h: Limiter

[0112] 40: Transmission controller (computer)

Claims

1. An automatic transmission, wherein, have: A speed change mechanism having: a pair of pulleys respectively disposed on the drive source side and the drive wheel side, and an annular component wound between the pair of pulleys; A limiter that specifies the lowest gear ratio on the lowest gear side of the transmission mechanism. When starting with the accelerator pedal opening less than a specified opening, it is set to the first gear ratio. When starting with the accelerator pedal opening greater than the specified opening, it is set to the lowest gear ratio, i.e., the second gear ratio, which is lower than the first gear ratio and is defined by the limiter.

2. The automatic transmission as claimed in claim 1, wherein, After starting with the second gear ratio set, the gear is shifted to a higher gear ratio than the second gear ratio after a specified time.

3. The automatic transmission as claimed in claim 1, wherein, After starting at the second gear ratio, if the temperature of the pulley surfaces of the pair of pulleys reaches a specified value or higher, the gear ratio is changed to a higher gear ratio than the second gear ratio.

4. The automatic transmission as claimed in claim 1, wherein, After starting with the second gear ratio set, if the temperature of the lubricating oil reaches a specified value or higher, the gear will be shifted to a higher gear ratio than the second gear ratio.

5. An automatic transmission that shifts to a parking gear ratio before changing from a driving state to a parking state, wherein, have: A speed change mechanism having: a pair of pulleys respectively disposed on the drive source side and the drive wheel side, and an annular component wound between the pair of pulleys; A limiter that specifies the lowest gear ratio on the lowest gear side of the transmission mechanism. When starting with the accelerator pedal opening less than a specified opening, the gear ratio is set to a higher gear than the parking gear ratio; when starting with the accelerator pedal opening greater than the specified opening, the gear ratio is set to the parking gear ratio. The parking gear ratio is the lowest gear ratio specified by the limiter.

6. An automatic transmission that shifts to a parking gear ratio before changing from a driving state to a parking state, wherein, have: A speed change mechanism having: a pair of pulleys respectively disposed on the drive source side and the drive wheel side, and an annular component wound between the pair of pulleys; A limiter that specifies the lowest gear ratio on the lowest gear side of the transmission mechanism. When starting with the accelerator pedal opening less than a specified opening, it is set to the parking gear ratio; when starting with the accelerator pedal opening greater than the specified opening, it is set to the lowest gear ratio specified by the limiter, which is on the lower gear side than the parking gear ratio.

7. An automatic transmission control method, the automatic transmission comprising: a transmission mechanism having: a pair of pulleys respectively disposed on a drive source side and a drive wheel side, and an annular member wound between the pair of pulleys; a limiter defining the lowest gear ratio on the lowest gear side of the transmission mechanism, wherein, When starting with the accelerator pedal opening less than a specified opening, the automatic transmission is set to the first gear ratio. When starting with the accelerator pedal opening greater than the specified opening, the automatic transmission is set to the lowest gear ratio, i.e., the second gear ratio, which is the lowest gear ratio specified by the limiter and is lower than the first gear ratio.

8. A control method for an automatic transmission, the automatic transmission comprising: a transmission mechanism having: a pair of pulleys respectively disposed on a drive source side and a drive wheel side, and an annular member wound between the pair of pulleys; a limiter defining the lowest gear ratio of the lowest gear side of the transmission mechanism, wherein the gear ratio is shifted to the parking gear ratio before changing from a driving state to a parking state, wherein... When starting with the accelerator pedal open less than a specified opening, the automatic transmission is set to a gear ratio higher than the parking gear ratio. When starting with the accelerator pedal open more than the specified opening, the automatic transmission is set to the parking gear ratio. The parking gear ratio is the lowest gear ratio specified by the limiter.

9. A control method for an automatic transmission, the automatic transmission comprising: a transmission mechanism having: a pair of pulleys respectively disposed on a drive source side and a drive wheel side, and an annular member wound between the pair of pulleys; a limiter defining the lowest gear ratio of the lowest gear side of the transmission mechanism, wherein the gear ratio is shifted to the parking gear ratio before changing from a driving state to a parking state, wherein... When starting with the accelerator pedal opening less than a specified opening, the automatic transmission is set to the parking gear ratio. When starting with the accelerator pedal opening greater than the specified opening, the automatic transmission is set to the lowest gear ratio specified by the limiter, which is on the lower gear side than the parking gear ratio.

10. A storage medium storing a program, the program being a computer-executable program of an automatic transmission, the automatic transmission comprising: a transmission mechanism having: a pair of pulleys respectively disposed on a drive source side and a drive wheel side, and an annular member wound between the pair of pulleys; a limiter defining the lowest gear ratio on the lowest gear side of the transmission mechanism, wherein, The computer performs the following steps: when starting with the accelerator pedal opening less than a specified opening, the automatic transmission is set to a first gear ratio; when starting with the accelerator pedal opening greater than the specified opening, the automatic transmission is set to the lowest gear ratio, i.e., the second gear ratio, which is lower than the first gear ratio and is specified by the limiter.

11. A storage medium storing a program for an automatic transmission that shifts gears to the parking gear ratio before changing from a driving state to a parking state, the automatic transmission comprising: a transmission mechanism having: a pair of pulleys respectively disposed on a drive source side and a drive wheel side; an annular member wound between the pair of pulleys; and a limiter defining the lowest gear ratio on the lowest gear side of the transmission mechanism, wherein... The computer performs the following steps: when starting with the accelerator pedal opening less than a predetermined opening, the automatic transmission is set to a gear ratio higher than the parking gear ratio; when starting with the accelerator pedal opening greater than the predetermined opening, the automatic transmission is set to the parking gear ratio. The parking gear ratio is the lowest gear ratio specified by the limiter.

12. A storage medium storing a program for an automatic transmission that shifts gears to the parking gear ratio before changing from a driving state to a parking state, the automatic transmission comprising: a transmission mechanism having: a pair of pulleys respectively disposed on a drive source side and a drive wheel side, and an annular member wound between the pair of pulleys; and a limiter defining the lowest gear ratio on the lowest gear side of the transmission mechanism, wherein... The computer performs the following steps: when starting with the accelerator pedal opening less than a specified opening, the automatic transmission is set to the parking gear ratio; when starting with the accelerator pedal opening greater than the specified opening, the automatic transmission is set to the lowest gear ratio specified by the limiter, which is on the lower side of the parking gear ratio.

Images