JPH0217259A - Automatic engine brake control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent an undesired up shift during the actuating of an automatic engine brake by performing the operation to select a manual engine brake and actuating it at a gear position in the low speed side of each engine brake. CONSTITUTION:During the braking, when a condition which needs the applying of engine brake is occurred, an automatic engine brake means makes an automatic transmission to shift down in the low speed so as to brake effectively. At this stage, the first gear position detecting means detects the gear position during the actuating of the engine brake. During the actuating of the engine brake, when the manual operation to select a manual engine brake is performed by a manual engine brake means, the second gear position detecting means detects the selected positions, and an automatic engine brake control means orders the automatic engine brake means to actuate the engine brake of the gear position in the low speed side among these selected gear positions. The undesired up shift can be thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device that enables manual engine braking to be obtained during braking of a vehicle by downshifting an automatic transmission.

(Prior Art) This type of automatic engine brake control device includes, for example, Nissan Motor ■ rL4N71B type, E4N71B type automatic transmission maintenance manual J (A261
As described in CO4), there is a known automatic transmission that downshifts to a low gear when a condition that requires engine braking to be applied during braking is established, and the vehicle continues to travel in this low gear.

(Problem to be Solved by the Invention) However, in such a conventional automatic engine brake control device, the manual engine brake range (
■When operating OD range, ■range, and D range)
If you select , manual operation will be prioritized, so the automatic engine brake will be deactivated, and if the manual engine brake gear position is higher than the automatic engine brake gear position (e.g. automatic: 2nd gear,
Manual: 3rd gear) not only does the engine brake that accompanies the downshift mentioned above not be obtained, but the automatic transmission also undesirably upshifts (2 to 3 upshift).
As a result, the driver may feel uncomfortable.

(Means for Solving the Problems) The present invention attempts to solve the above-mentioned problems by operating automatic engine braking based on the gear position on the lower gear side of the gear positions of automatic and manual engine braking. As conceptually shown in FIG. 1, an automatic transmission is configured to provide automatic engine braking or manual engine braking by downshifting to a low gear by automatic engine braking means or manual engine braking means during braking. a first detecting gear position during operation of said automatic engine braking means;
a gear position detection means, a second gear position detection means for detecting a selected gear position of the manual engine brake means, and when a manual operation to select manual engine brake is performed during automatic engine brake operation;
Automatic engine brake control means is provided for issuing an engine brake command to the automatic engine brake means according to a gear position of a low gear among the gear positions detected by the first and second gear position detection means. shall be.

(Function) When a situation arises in which engine braking is required during braking, the automatic engine braking means downshifts the automatic transmission to a low gear, thereby making it possible to apply engine braking.

At this time, the first gear position detection means detects the gear position I in which the automatic engine braking means is operating. By the way, when the manual engine brake means performs a manual operation to select manual engine brake while the automatic engine brake is in operation, the second gear position detection means detects the gear position selected by the manual engine brake means. The automatic engine brake control means issues an engine brake command to the automatic engine brake means such that the engine brake at a lower gear position among these gear positions is activated.

Therefore, even if a manual engine brake selection operation is performed during automatic engine braking, an undesired upshift will not occur and the desired downshift will provide engine braking, and the driver will not feel any discomfort. .

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 2 is a 0-production car ■r RE4ROIA type automatic toss transmission maintenance manual J (A261CO7)
An embodiment of the present invention device configured to be useful for the 4-speed automatic transmission with OD (overdrive) described in 1 is shown as a functional block diagram, in which 1 is the automatic transmission, 2 is its shift control means, and 3 is a functional block diagram. is the gear position depending on the shift pattern! decision means,
4 is a manual engine brake selection means. The vehicle speed detection means 5 and the deceleration detection means 6 include a vehicle speed sensor (not shown) that picks up the teeth of a pulse gear that rotates together with the output shaft of the automatic transmission 1 and generates a pulse signal. Then, each time a pulse signal is generated, the program shown in FIG. 3(a) is executed to increment the counter C to 100.
The program shown in FIG. 3(b) is executed by a regular interrupt every m5ec or 354 m5ec to determine the vehicle speed vSP and the vehicle deceleration α. In FIG. 3(b), in order to clear the above-mentioned counter C in step 24,
The count value of counter C at the time of interrupt is vehicle speed vSP
The difference between this count value C and the previous value C' corresponds to the acceleration/deceleration α of the vehicle. Therefore, first, in step 20, the vehicle speed vSP is determined as a function f(C) of the count value C, and in step 21, the previous value C' of the counter and the current value (l
The difference ΔC (Δc=c-c') from the IC is calculated, and in step 22, the vehicle deceleration α is determined as a function g (ΔC) of this difference ΔC. In step 23, the current count value C is converted to C.
’ and store it in memory for next time. Note that in order to obtain the deceleration α, the longitudinal G of the vehicle may be used instead of the vehicle speed vSP.

The manual engine brake selection means 4 is operated by the driver when the driver desires engine braking (overdrive prohibition switch, manual valve ■ range or lunge position), and the gear position determination means 3 receives the manual engine brake signal from the means 4. The vehicle speed vSP and other shift control information 13 from the means 5 are based on the corresponding shift pattern if the manual engine brake signal is input, or based on the normal shift pattern if the manual engine brake signal is not input.
The required gear position is determined according to (throttle opening TH, hydraulic oil temperature, etc.). The shift control means 2 controls the automatic transmission 1 to shift to the required gear position.

The downshift gear determining means 7 for automatic engine braking downshifts the automatic transmission 1 to a gear position lower than the gear position selected by the shift control means 2 under driving conditions that require engine braking, and also downshifts the automatic transmission 1 to a gear position lower than the gear position selected by the shift control means 2. means 3 to determine whether engine braking is necessary.
In addition to inputting the requested gear position from , the vehicle speed vsp from means 5 , deceleration (α) information from means 6 , and manual engine brake signal from means 4 , the brake detection means 9 detects depression of the brake pedal 8 . and the set delay time of the off-delay setting means 12 in response to the signal from the idle state detection means 11 which detects the release of the accelerator pedal 10. It is assumed that the means 12 sets a time for delaying the depression signal when the accelerator pedal 10 is depressed again from the released state.

4 to 6 show control programs for the automatic engine braking downshift speed determining means 7.

In the control shown in FIG. 4, in step 30, it is checked whether the manual valve is in the forward automatic shift (D) range. Other than D range, that is, 2nd gear engine brake (II
) range and the first speed engine brake (I) range, the automatic engine brake according to the present invention is not required, so in step 31 a flag FDS indicating a downshift shift command for automatic engine brake is set. FDS 3
Reset each. When FDS 2 is set to 1, it issues a downshift command for automatic engine braking to 2nd gear and prohibits upshifting to 3rd gear or higher.)
, FDS 3 issues a downshift command for automatic engine braking to 3rd gear when set to 1 (4
(forbids upshifting to high speed).

If it is determined in step 30.32 that the D range (this control is only applicable to the D range 00 prohibited operation) and the release of the accelerator, the idle flag FI is determined in step 33.
Check whether DL is already 1, and if not, set FIDL=1 to indicate the accelerator release state in step 34.35, and then set PDS 2.
Reset FDS 3 to 0. Already P in step 33
If it is determined that IDL=1, step 3
In step 6, it is checked whether the driver desires to prohibit OD, and if so, step 35 is executed to prohibit automatic engine braking downshift to third gear.

In the next step 37, it is checked whether or not the brakes are being applied.Since a large engine brake is not required while the brakes are not being applied, steps 38 to 40 are followed by an automatic engine brake jump 4→2 downshift. To prohibit shifting, if the current gear position GPM is 4th, FDS
2=O and PDS 3=1 instead.

If it is determined in step 37 that braking is in progress, automatic engine braking is required, so it is checked in steps 41 and 42 whether or not automatic engine braking is already in operation. During automatic engine braking operation with FDS2=1 or r'Ds3=1, (TD
Each time the downshift timer TDS, which is set in S-i) and decremented at regular intervals (for example, 10m5ec) by the program shown in FIG.
=O and FDS3=0, when the automatic engine brake is not activated, a downshift speed change command for the automatic engine brake is issued as follows.

That is, in steps 44 and 45, it is checked whether the currently used gear position is 4th speed or 3rd speed. If it is the 4th gear, in step 46, a downshift line (an example of which is shown in Fig. 9) corresponding to the currently used gear position (4th gear) and the vehicle speed VSP are used to calculate the down deceleration ΔC74, and in step 47, ΔC (
14 and the actual vehicle deceleration ΔC obtained by the processing in Fig. 3, etc.), since these decelerations are negative values, ΔC
If ≧ΔC44 (area to the right of the 4th gear downshift line in FIG. 9), the control in this example is unnecessary, so only when ΔC<ΔC44, step 48 shifts the gear position by 1 from the currently used gear position (4th gear).
The set deceleration ΔC0 is calculated from the lower set line (3rd gear set line) and the vehicle speed vSP, and in step 49, ΔC13 is calculated.
and the actual vehicle deceleration ΔC. Here ΔC≧Δ
C31, that is, the area to the right of the 3rd gear set line shown in the figure, is the area where a 4→3 downshift is required, so in step 50, the deceleration ΔC and the rimming value ΔCLN? Compare with 3. Here, if ΔC≧ΔC 78, that is, if the deceleration ΔC is in the region below the 3rd speed limit line shown in the figure, the control in this example is unnecessary, so step 5 is performed only when ΔC is ΔCLNT3.
FDS2 to correspond to 4→3 downshift request in 1
Set the 4→3 downshift speed change command as =O1FDS3.1.

If it is determined in step 45 that the third speed is being selected, the 3→2 downshift control in steps 52 to 57 is performed in the same manner as the 4→3 downshift control in steps 46 to 51 described above, and the conditions are satisfied. In this case, 3 → 2 in step 57
FDS2・LF to respond to downshift requests
Set DS3=0 and set the 3→2 downshift speed change command. In addition, in step 49 mentioned above, ΔC ΔC0
Since the control proceeds to steps 54 to 57 when
If it is within the area surrounded by the speed limit line, that is, the area where a 4->2 downshift is to be performed, a 4->2 downshift shift command will be issued. Further, after steps 51 and 57, the downshift timer TDS is set to TDS-t in step 58.

If it is determined in step 32 that the accelerator pedal is being depressed, then in step 59 it is checked whether the idle flag PIDL is 1 or not to see if the accelerator has been released so far, that is, whether or not the accelerator pedal is being depressed again. In the case of re-depression, the delay time is set in the timer T in steps 60 to 64, and the idle flag PIDL is set in step 65.
is reset to 0 to indicate the accelerator pedal depression state. If it is determined in step 59 that the pedal is not depressed again, these processes are skipped and the control proceeds to step 66.

The above delay time occurs when the accelerator pedal is pressed again, when automatic engine braking downshift (FDS 2=l,
PDS3=1) immediately ends (FDS2=0,
This is to finish the process with a delay without PDS3=O), and from the determination results in steps 60 and 61, if FDS2=0 and FDS3-0 downshifting is not performed, there is no need for a delay time in step 62. When T-0 and automatic engine braking downshift (to 3rd gear) with PDS3=1 is being performed, step 63 is performed.
Set the corresponding delay time DLY34 in timer T,
If FDS2=1 and automatic engine braking downshift (to 2nd gear) is being performed, step 64 is performed.
The corresponding delay time DLV23 is stored in the timer T.

In step 66, when the timer T, which is decremented by the regular interrupt of the program shown in FIG.
Control proceeds to step 67.

In steps 67 and 68, the flag FDS2. FDS
3, it is checked whether automatic engine braking was not in operation, whether automatic engine braking was being performed by downshifting to third gear, or whether automatic engine braking was being performed by downshifting to second gear. If the automatic engine brake is not activated, do nothing (FDS 2=0
．． If a downshift to 3rd gear is in progress, set FDS3=O to end this in step 69. If a downshift to 2nd gear is in progress, shift to 3rd gear. In order to terminate the automatic engine brake via the automatic engine brake at step 70, first, in step 70, a delay time DLY234 to be set for releasing the third speed engine brake after the second speed engine brake is released is set by the timer T. Step 7
1, FDS2=O commands the release of the second speed engine brake, and PDS3=1 commands the start of the third speed engine brake. Note that, at this time, the release of the third speed engine brake is executed after the delay time DLY234 through a loop of steps 66 to 69, and the automatic engine brake is completely terminated here.

Step 72 is an engine overspeed determination step, which is executed by the subroutine shown in FIG. That is, based on the determination in steps 74 and 75, whether automatic engine braking is not in operation (FDS 2 = O, PDS 3 = O), 3rd gear engine braking is in progress (PDS3 = 1), or 2nd gear engine braking is in progress (PDS2 = 1) Check. Nothing is done while the automatic engine brake is not in operation, and when the vehicle speed vsp reaches a set value TMAX 3 or higher that would cause the engine to overspeed in step 76 during third gear engine braking, the third gear engine brake is naturally activated in step 77. It is stopped by PDS3=O (the gear position is returned to the original high speed gear) to prevent engine overspeed. During 2nd gear engine braking, when the vehicle speed vSP reaches a set value VMAX 2 or more that causes the engine to overspeed in step 78, the 2nd gear engine brake is stopped by FDS2=O in step 79 to overspeed the engine. prevent. In step 79, a third engine brake is further commanded by FDS3=1, and thereafter in steps 76 and 77, downshifting for automatic engine braking is inhibited to prevent overspeeding of the engine.

7 and 8 show control programs by the speed change control means 2 and gear position determining means 3 in FIG. 2. FIG.

In FIG. 7, first, in step 80, the vehicle speed vsp and throttle opening TH, etc., which indicate the driving state are read, and in step 81, the vehicle speed is Zero-order step 82 determines the target gear position GP corresponding to vSP, throttle opening TH, etc. The target gear position GP of the lever is set to the currently used gear position GPN. Step 83
．． 84, automatic engine brake is not activated (FDS 3
=O, FDS 2=0), 3rd gear engine braking (FDS3=1), 2nd gear engine braking (FD
S2=1). While the automatic engine brake is not in operation, step 85 is directly executed to perform normal speed change control so that the gear position becomes the target gear position GP determined in step 81.

During 3rd gear engine braking, it is checked in step 86 whether the target gear position GP is higher than 3rd gear. If it is, then in step 87 GP is set to 3, and then step 85 is executed to shift down to 3rd gear. Shift and apply automatic engine braking. If CP<3, there is no need to shift to 3rd gear for engine braking, so step 8.
After this shift command is canceled by FDS3=O in step 8, normal shift control is performed by executing step 85.

During 2nd gear engine braking, it is checked in step 89 whether the target gear position GP is higher than 2nd gear, and if it is, then in step 90 GP is set to 2, and then step 85 is executed to downshift to 2nd gear. If GP<2, there is no need to downshift for 2nd gear engine braking, so in step 91 PDS2=
After this shift command is canceled by O, normal shift control is performed by executing step 85.

Depending on the powertrain of the automatic transmission, 2nd gear,
When engine braking is required in third gear, an engine braking clutch must be activated, and in the automatic transmission described in the above document to which this example device is applied, an overrun clutch is used for this purpose. Equivalent to. This engine braking clutch enables engine braking in the second and third speeds by controlling its operation according to the control program shown in FIG. That is, step 92
In step 93 or 94, it is determined that the throttle opening TH is less than the minute setting value, and in step 93 or 94, FDS2-1 or P
If it is determined that automatic engine braking is in progress with DS3=1, the engine braking clutch is engaged in step 95 to enable engine braking as requested. However, in other cases, since engine braking is not necessary, the engine braking clutch is released in step 96.

(Effects of the Invention) Thus, as described above, the automatic engine brake control device of the present invention, when a manual operation is performed to select manual engine brake while automatic engine brake is in operation,
Since automatic engine braking is activated based on the gear position of the low engine braking speed, the desired downshift engine braking can be obtained without undesired upshifts, and the driver may not feel any discomfort. It disappears.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of the automatic engine brake control device of the present invention, Fig. 2 is a functional block diagram showing an embodiment of the device of the present invention, and Figs. 3 to 8 each show a rotation control program. Flowchart FIG. 9 is a characteristic diagram showing vehicle speed-deceleration characteristics on the same side. l... Automatic transmission 2... Speed change control means 3.
...Gear position determining means 4...Manual engine brake IN means 5...
Vehicle speed detection means 6...Deceleration detection means 7...Downshift determination means for automatic engine braking 9...Braking operation detection means 11...Idle state detection means 12...Off-delay setting means

Claims (1)

[Claims] 1. In an automatic transmission that is downshifted to a lower gear by automatic engine braking means or manual engine braking means during braking to provide automatic engine braking or manual engine braking, the gear position during operation of the automatic engine braking means; a first gear position detection means for detecting the selected gear position of the manual engine brake means; and a second gear position detection means for detecting the selected gear position of the manual engine brake means, and a manual operation for selecting the manual engine brake is performed while the automatic engine brake is in operation. automatic engine brake control means for issuing an engine brake command to the automatic engine brake means according to a lower gear position among the gear positions detected by the first and second gear position detection means. An automatic engine brake control device for an automatic transmission characterized by: