JPH0341259A - Power ability control device for vehicle provided with automatic transmission - Google Patents

Abstract

PURPOSE:To always utilize function of an engine at a maximum by changing a transmission point under the same condition at the second time and later such that an engine speed at the transmission approaches a target engine speed. CONSTITUTION:Transmission is performed at a transmission point previously set in a transmission map dependently on a signal from a vehicle speed detecting means and an engine load detecting means. A comparing means compared an engine speed at the transmission detected by an actual engine speed detecting means with a target engine speed previously set for this transmission by means of a target engine speed detecting means. The transmission points under the same condition next time or later are learned and the transmission point in the transmission map is changed such that the engine speed at the time of transmission approaches the target value. It is thus possible to utilize function of the engine at a maximum, and to prevent the seizure etc. of the engine.

Description

[Detailed description of the invention]

(Industrial Field of Application 1) The present invention relates to a power performance control system for a vehicle equipped with an automatic transmission, which is configured to perform gear shifts at predetermined shift points depending on vehicle speed and engine load.

[Prior art 1] Conventionally, a gear transmission mechanism and a plurality of frictional engagement devices are provided, and the engagement of the frictional engagement devices is selectively switched by operating a hydraulic control device. Automatic transmissions configured to achieve either of the following are already widely known. In general, automatic transmissions installed in heavy vehicles vary depending on vehicle speed and engine load (e.g. throttle opening).
``Speed change'' is predetermined (see Fig. 6 (A)),
A shift is executed when the driving state crosses this shift point due to a change in vehicle speed or engine load. Generally, in the case of upshifting, the higher the shift point is set, the more the vehicle's power performance improves. This is because if the shift point is high, lower gears will be used more frequently at the same vehicle speed and engine load. In light of these circumstances, so-called electronically controlled automatic transmissions, which have become popular in recent years, have a shift pattern in which the shift point is set high with emphasis on power performance, and a shift pattern in which the shift point is set high with emphasis on fuel efficiency. Equipped with a low gear shift pattern,
Some vehicles are configured so that the driver can select one of these, allowing the driver to drive more in accordance with his or her preferences (for example, Japanese Patent Laid-Open No. 17246/1983). In the case of a shift pattern that emphasizes power performance, shifts are executed in a high rotation range that takes into consideration the so-called red zone of the engine. (Problem to be Solved by the Invention 1) However, there are always variations in the output torque of an engine that are unique to the engine, occurring at the time of manufacture or over time, and even with the same throttle opening, the output torque may vary slightly. Furthermore, even if the throttle opening is the same, the output torque of the engine varies considerably depending on the driving environment, which changes relatively slowly, such as the intake temperature and the warm-up state. Therefore, the engine speed at the time of a gear shift decision does not vary much as long as the shift point is fixed, but as mentioned above, the engine torque generated at that time varies, and furthermore, the friction engagement device of the hydraulic control system Due to variations in line pressure, etc., the amount of engine revving (increasing engine speed) from the time the gear shift is determined to the time the gear shift actually starts varies greatly, and as a result, the actual gear shift is delayed. The engine speed at the time of start will vary widely.In the case of an upshift, the engine speed at this time is the highest, so with emphasis on power performance, the engine speed should be set just before the red zone. Conventionally, when using an engine in this range, the shift point was set with enough margin to avoid entering the red zone even if there were variations in the engine speed when the shift actually started. Therefore, if the actual engine speed fluctuates downward, even though it is possible to drive with even higher power performance, the power performance will be considerably lower (a problem such as not being able to float) will occur. The present invention has been made in view of such conventional problems, and particularly, when running at around the maximum engine speed, it is possible to solve various variations. It is an object of the present invention to provide a power performance control device for a vehicle equipped with an automatic transmission 81 that can always make the maximum performance of the engine exhibited regardless of the situation. As shown in Figure 1, in a power performance control system for a vehicle equipped with an automatic transmission, which is configured to perform a shift at a predetermined shift point depending on medium speed and engine load, means for detecting a rotation speed; means for comparing the detected engine rotation speed with a target engine rotation speed predetermined for the gear shift; The above object is achieved by including means for changing the shift point of subsequent shifts under the same conditions so that the speed approaches the engine speed. (Function) In the present invention, the engine speed during gear shifting is detected,
The detected engine speed is compared with a target engine speed predetermined for the shift. Now, consider a case where the detected engine speed is lower than the target engine speed, for example. In this case, the engine still has quite a bit of room left in the so-called red zone, so you can raise the shift point a little higher to further increase the engine speed before shifting. . Therefore, in such a case, the present invention performs learning control to set the shift point higher, so that the engine speed can be further increased. Conversely, when the engine speed varies higher than the target engine speed, there is almost no margin for the red zone, so the shift point can be moved slightly lower to protect the engine. (Embodiment) FIG. 2 shows an overall outline of a vehicle automatic transmission to which this embodiment is applied. This automatic transmission includes a torque converter section 20 and an overdrive mechanism section 40 as its transmission sections.
and an underdrive mechanism section 60 with three forward stages and one reverse stage. The torque converter section 20 is of the well-known type B, which includes a pump 21, a turbine 22, a stake 23, and a lock-up clutch 24. The overdrive mechanism section 40 includes a set of planetary gears including a sun gear 43, a ring gear 44, a planetary pinion 42, and a carrier 41, and the rotational state of the planetary gears is controlled by a clutch CO, a brake So, and a one-way clutch. It is controlled by Fo. The underdrive enclosure 60 has a common sun gear 6.
1. Ring gear 62.6S, planetary binion 64.
65 and a carrier F66.67, and the rotation state of these two sets of planetary gears HM and the connection state with the overdrive mechanism are controlled by the clutch C1,
C2, brake B, ~83. and one-way clutch Fl,
It is controlled by F2. Since the mechanical structure of this transmission section and the hydraulic pressure control device that controls it is well known, a detailed explanation thereof will be omitted, with only a skeleton diagram shown in FIG. 2. This automatic transmission includes a transmission section as described above,
and a computer (ECU>84. The computer 84 includes a throttle sensor 80 that detects the throttle opening θ to reflect the output (torque) of the engine 1.
．． Signals from a vehicle speed sensor (rotational speed sensor of the output shaft 70) 82 that detects the vehicle speed No., an engine rotational speed sensor 99 that detects the rotational speed of the engine 1, and the like are input. The computer 84 drives and controls the solenoid valves S+, Sz (for shift valves), and SL (for lock-up clutch) in the hydraulic control circuit 86 according to a preset throttle opening-vehicle speed shift point map, and Shifting is performed by performing combinations of engagement of each clutch, brake, etc. as shown in the figure. Further, the computer 84 compares the actual engine speed and the target engine speed when the actual speed change starts (at the start of the inertia phase) after the speed change command, and sets the speed change point on the speed change map based on this difference. Learn and correct. FIG. 4 shows the control flow executed within the computer 84. First, in step 102, a shift decision is made in accordance with a predetermined shift point map of vehicle speed versus throttle opening as shown in FIG. 6(A). Next, in step 104, an on or off command is issued to the 7HFa valve S1 or Sz for controlling the shift valve in order to supply hydraulic pressure to the corresponding frictional engagement device (clutch or brake). In step 106, the engine rotational speed Ne immediately before the start of the inertia phase is monitored. Immediately before the start of the inertia phase can be determined by detecting the rate of increase in the engine speed Ne. The reason for monitoring immediately before the start of the inertia phase is because the engine speed continues to rise until this point, and as the inertia phase begins, the engine speed starts to decrease, so the engine speed is the highest just before the start of the inertia phase. It's for a reason. In step 108, J3 determines a value (Neo− N+). Note that this constant N1 is a zero or positive constant for providing hysteresis when the shift point is changed to a higher position. If it is determined in step 108 that Neo Nt>Ne, the shift actually starts at shift point No. 1 (output shaft rotation speed: corresponds to vehicle speed) used for the current shift decision (inertia phase starts). Since the engine speed (at the time of
A higher value is determined based on the expression determined by Neo and Nol, for example, the following relational expression. No+-+'=No + + to + + (Neo N
e)/ρ+-Not No;++= a+Nor++'+ (1-a+)N
o i Here, ρ is the gear ratio before shifting, K1 and No+ are predetermined constants, and a is an arbitrary number that satisfies ○≦a1≦1. On the other hand, in step 108, N eO−N + >
If it is determined that it is not Ne, the process proceeds to step 112. In step 112, the detected engine rotation Ne
and a predetermined constant N for the target engine speed NeO.
2 plus l1H (Neo+N2). This constant N2 is a zero or positive constant to provide hysteresis for changing the shift point to a lower position. If it is determined in step 112 that Neo + N2 <Ne, this means that at the shift point Not used for the current shift determination, the actual engine speed Ne is too high relative to the target engine speed NeO. Therefore, the shift point N Oi used for the next shift judgment under the same conditions
ll is set to a lower value based on an expression determined by Ne, Neo, and Nof, for example, the following relational expression. No;++”=Noi Kz(Ne Neo)/ρ
+N02 No;+1= azNo;++x+ (1az)No
i where K2 and NO2 are predetermined constants, az
is any reason that satisfies ○≦82≦1. In step 112, Neo+N 2 <Ne r
If it is determined that there is no such information, the process advances to step 114. When proceeding to step 114, Neo-Nl≦N
Since this is a case where e≦NeO+Nz is satisfied, if the shift is performed using the shift point Noi used for the current shift judgment, the target engine speed NeO and the actual engine speed N
This means that the difference with e is small. Therefore, the shift point N Oil used for next shift judgment under the same conditions
is set to be the same as the shift point Noi used this time. In this way, when the actual engine speed Ne fluctuates lower than the target speed NeO, it means that there is still room for the red zone, so the shift point is changed to a higher position and the previous gear ( It is possible to expand the range of use of the low gear (low gear) and to execute gear changes after bringing the engine speed close to the maximum engine speed. On the other hand, when the engine speed varies greatly relative to the target engine speed, by lowering the shift point, it is possible to secure margin for the red zone and protect the engine. Next, FIG. 5 shows a control flow that is a further development of the above embodiment. This fli control flow is such that if the actual engine speed fluctuates so high that it enters the red zone,
This system determines that some kind of abnormality has occurred in the automatic transmission, issues a warning of the abnormality, and changes the shift point to an extremely low shift point exclusively for failures. In this embodiment, the flag F1, which was initially set to zero, is set to one when an abnormality is determined. In step 200, the value of this flag F is first determined. If the field of this flag F1 is not 1, it indicates that no abnormality has been determined so far.
Proceed to step 102. Steps 102 to 114 are completely the same as the control flow shown in FIG. 3, so repeated explanation will be omitted. In this control flow, in step 112 NeO+
When it is determined that N2<Ne, the process proceeds to step 215 and it is determined that N eO+N 3 > Ne. Here, N3 is a positive constant that is considerably larger than N2. When NeO+N3>Ne holds true, the engine speed Ne has not yet entered (or approached) the red zone, so the process proceeds to step 21G, where the shift point is (slightly) lowered, similar to step 116 in FIG. Learning control to change the eyes is executed. On the other hand, if the force is applied so that NeO+N3>Ne does not hold, it means that the engine speed has entered the red zone region (or has reached region 1 just before entering). The process proceeds to step 218, where it is determined that the automatic transmission is abnormal, and the flag E1 is set to 1. Further, in step 220, a fail warning light is displayed. When the flag F1 is set to 1, the next time the flow is started, it is determined that the flag F+ is 1 in step 200, so the process proceeds to step 222 and the process as shown in FIG. 6(B) is performed. A change is made to a shift point that is set exclusively for the failure, that is, set to an extremely low value. Then, in step 224, a shift is determined according to this low-set shift point map, and in step 226, a hydraulic pressure supply command is issued to the frictional engagement device. As a result, it becomes possible to prevent the engine speed from entering the red zone region or becoming extremely close to the red zone region. [Effects of the Invention] As explained above, according to the present invention, the engine speed can be always increased to the maximum regardless of various variations, but it can be used so as to never enter the red zone. An excellent effect can be obtained. As a result, it becomes possible to always make the most of the engine's functions regardless of various variations, and it becomes possible to prevent engine seizure and the like.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the gist of the present invention, and FIG. 2 is a block diagram showing the gist of the present invention.
FIG. 3 is a schematic block diagram showing a power performance control system for an automatic transmission vehicle to which an embodiment of the present invention is applied. J, a diagram showing the operating state of the frictional engagement device; FIG. 4 is a flowchart showing the control flow executed in the computer of the control device; FIG. 5 is a further development of the control flow in FIG. FIGS. 6A and 6B are diagrams showing examples of shift point maps. Ne...Engine speed, Neo...Target engine speed, Noi...Current shift point (corresponds to output shaft speed 2 vehicle speed) N Ois...Next shift point.

Claims (1)

[Claims] (1) In a power performance control device for a vehicle equipped with an automatic transmission configured to perform a shift at a predetermined shift point depending on the vehicle speed and engine load, means for detecting the engine rotation speed during a shift; The detected engine speed and
means for comparing the target engine speed with a predetermined target engine speed for the gear change; and based on the comparison result, a means for comparing the speed with a target engine speed predetermined for the gear change; A power performance control device for a vehicle equipped with an automatic transmission, comprising: means for changing a shift point;