JPH10252873A - Traveling resistance detecting device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the inappropriate control based on the traveling resistance having a large error, and while to shorten the time for stopping the estimate of the traveling resistance so as to secure the responsiveness of control. SOLUTION: In this device, a variable ΔTVO of a throttle open degree TVO is computed (S12-S14). When a sudden change of the engine load in the increasing direction is judged on the basis of the variable ΔTVO (S15), estimate of the traveling resistance is stopped, and a first stop time TM1 for continuing the stop of estimate is set longer, as the open degree before a sudden increase TVOBASR is smaller (S16). On the other hand, when a sudden increase of open degree TVO is stopped, a second stop time TM2, which is shorter, as a difference between the last open degree TVONEW and the open degree before the sudden increase TVOBASE is smaller, is set (S18). In the case where the second stop time TM2 is shorter (S19), computing of the traveling resistance is stopped continuously to the sudden increase by the second stop time TM2 in place of the first stop time (S20).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting running resistance of a vehicle, and more particularly to a technique for maintaining the accuracy of estimating running resistance based on an engine load.

[0002]

2. Description of the Related Art In a shift control of an automatic transmission for a vehicle, a method is generally used in which a shift speed is determined by referring to a shift map in which a shift speed is set in advance according to a throttle opening and a vehicle speed. However, in the configuration in which the gear position is determined as described above, since the running resistance change is not considered, for example, when traveling on an uphill road, an unnecessary upshift is performed by releasing the foot from the accelerator when entering a corner, Sometimes, the highest speed is selected, so that the engine brake cannot be actuated and the load on the foot brake increases, which causes a problem.

Therefore, in the device disclosed in Japanese Patent Publication No. 4-4351, for example, the torque generated by the engine is calculated based on the throttle valve opening and the engine speed, and the calculated torque, vehicle acceleration and vehicle weight are calculated. By calculating the running resistance (gradient resistance) of the vehicle on the basis of the above, and comparing the running resistance with a preset value set in accordance with the shift speed, a desired acceleration (engine brake) can be obtained when the vehicle is going downhill. The gear position is determined so as to be obtained.

[0004] Japanese Patent Application Laid-Open No. 5-71623 discloses that
When the engine load suddenly changes, the accuracy of estimating the running resistance (driving force) deteriorates. Therefore, when the engine load suddenly changes, the estimating of the running resistance is stopped, and the change of the shift characteristic is stopped accordingly. There is a disclosure. Specifically, the absolute value of the change amount of the throttle opening is compared with a predetermined value, and when the absolute value of the change amount is equal to or more than the predetermined value, the estimation of the running resistance and the change of the shift characteristic are stopped for a fixed time. Configuration.

[0005]

By the way, for example, when the throttle is suddenly operated from the intermediate opening to the fully closed position,
When the estimation accuracy recovers earlier than when suddenly operated from fully closed to fully open, and, for example, when the throttle is suddenly opened from fully closed to fully open and immediately returned to fully closed, In this case, the running resistance can be estimated with sufficient accuracy within a shorter time than when the vehicle is suddenly opened from the fully closed state to the fully open state and is kept at the fully open state.

[0006] However, the above-mentioned Japanese Patent Application Laid-Open No. 5-71623 has been proposed.
In the method disclosed in Japanese Patent Laid-Open Publication No. H06-27138, since the estimation of the running resistance is always stopped for a fixed time when a sudden change in the engine load is determined, the stopping time may be longer than necessary, and the running resistance may be reduced. There is a problem that the responsiveness of the used control may be deteriorated. The present invention has been made in view of the above-described problems, and it is possible to reliably avoid inappropriately changing the shift characteristics and the like due to deterioration of the estimation accuracy of the running resistance (driving force) based on the engine load, and to avoid unnecessary changes. It is possible to prevent the estimation control of the running resistance from being stopped.

[0007]

According to a first aspect of the present invention, there is provided a vehicle running resistance detecting apparatus for calculating a vehicle running resistance equivalent value based on at least a parameter including an engine load. It is configured to determine whether the engine load has suddenly changed, and to stop the calculation of the running resistance equivalent value for a predetermined stop time when the engine load suddenly changes, and to change the stop time according to the engine load before the sudden change. .

According to this configuration, when a sudden change in the engine load is determined, the estimation of the running resistance is stopped for a predetermined stop time, and the calculation of the running resistance having a large error is avoided. (Stop time) is not constant, but is changed according to the state of the engine load before the engine load suddenly changes. Thus, for example, when increasing the engine load to the full load, different stop times can be set for the case where the load is increased from the intermediate load and the case where the load is increased from the low load. Sometimes it is possible to shorten the suspension time.

In order to stop the calculation for estimating the running resistance equivalent value, in addition to not executing the processing for calculating the running resistance equivalent value itself, the estimated value of the running resistance equivalent value is held at the value immediately before the stop or the calculation is performed. Including not using the calculated running resistance equivalent value for speed change control, and further, in the case of using the calculated running resistance equivalent value as a weighted average, changing the weighting in the weighted average. This also includes reducing the degree of influence of the latest calculation value.

[0010] The engine load can be represented by a throttle opening and the like. In the invention according to claim 2, it is determined whether or not the engine load is suddenly changed, and when the engine load is suddenly changed, the calculation of the running resistance equivalent value is stopped for a predetermined stop time, and the engine before the sudden change is configured. The suspension time is changed according to the load and the latest engine load.

According to this configuration, the engine load is returned after the operation of suddenly changing the engine load (throttle opening / closing operation) is performed from the engine load before the sudden change and the latest engine load (the engine load after the sudden change). It is possible to judge whether or not an appropriate operation has been performed.For example, even when the same throttle operation is performed from the fully closed state, it is possible to maintain the maximum opening degree of the opened operation or to return to the fully closed state after the opening operation. Whether the operation was performed,
Different stop times will be set. In general, the estimation accuracy recovers in a shorter time when the return operation is performed. Therefore, the stop time may be shortened as the engine load before the sudden change is closer to the latest engine load (the engine load after the end of the sudden change). .

According to the third aspect of the present invention, it is determined whether or not the engine load is suddenly changed, and when the engine load is suddenly changed, the calculation of the running resistance equivalent value is stopped for a predetermined stop time. A first stop time is set according to the previous engine load, and a second stop time is set according to the engine load before the sudden change and the latest engine load, and the first stop time and the second stop time are set. The calculation is stopped based on a comparison with the stop time.

According to this configuration, the calculation of the running resistance equivalent value is actually stopped from the first stop time based on the operation for suddenly changing the engine load and the second stop time based on the return operation after the sudden change operation. Time is determined. In the invention according to claim 4, the shorter of the first stop time and the second stop time is selected, and the calculation of the running resistance equivalent value is stopped based on the selected stop time. did.

According to this configuration, the shorter one of the first stop time based on the operation for suddenly changing the engine load and the second stop time based on the return operation after the sudden change operation is selected, and only the shorter stop time is selected. The calculation of the running resistance equivalent value is stopped.

[0015]

According to the first aspect of the present invention, the time for stopping the calculation of the running resistance equivalent value is determined from the magnitude of the engine load before the sudden change, so that the estimation accuracy can be recovered at a relatively early time, for example. When the load suddenly increases, it is possible to prevent the estimation calculation from being uselessly stopped, so that there is an effect that the responsiveness of the control based on the running resistance can be secured.

According to the second aspect of the present invention, the time for stopping the calculation of the running resistance equivalent value is determined according to the engine load before the sudden change and the latest engine load. To determine the stop time,
When the estimation accuracy of the running resistance is returned relatively quickly by the returning operation, it is possible to avoid the useless suspension of the running resistance, and thus it is possible to ensure the responsiveness of the control based on the running resistance.

According to the third aspect of the present invention, the running resistance equivalent value is finally determined based on the suspension time required from the engine load before the sudden change and the suspension time required depending on the presence or absence of the return operation after the sudden change. Since the time to stop the calculation is determined, it is possible to set a more appropriate stop time, and it is possible to ensure the estimation accuracy and to reliably prevent the useless stop of the calculation.

According to the fourth aspect of the present invention, the shorter of the suspension time required from the engine load before the sudden change and the suspension time required depending on the presence or absence of the return operation after the sudden change is selected, so that the running resistance is selected. There is an effect that the time during which the calculation of the equivalent value is stopped is shortened to the utmost, and the response of the control based on the running resistance can be improved.

[0019]

Embodiments of the present invention will be described below. FIG. 1 shows a system configuration of a vehicle internal combustion engine according to the embodiment. In FIG. 1, the engine 1 is connected to an automatic transmission 2 so that the generated torque is transmitted to driving wheels (not shown). The automatic transmission 2 includes a torque converter 3 for inputting torque generated by the engine 1, a multi-stage transmission gear mechanism 4 for inputting an output of the torque converter 3, shifting the output, and a hydraulic pressure (not shown) for driving these. And a mechanism.

The hydraulic mechanism of the transmission gear mechanism 4 includes:
Solenoid valves 6A and 6B are incorporated, and by switching the combination of opening and closing of the solenoid valves 6A and 6B, the combination of engagement and disengagement of each clutch included in the transmission gear mechanism 4 is switched, and a desired gear The shift is performed. The ON / OFF control of the plurality of solenoid valves is performed by CPU, ROM, R
The control is performed based on a control signal from a control unit 50 including an AM, an A / D converter, an input / output interface, and the like.

The control unit 50 receives signals from various sensors. As the various sensors, a throttle sensor 7 that outputs an output signal corresponding to the throttle opening TVO, and a vehicle speed sensor 8 that detects a rotation speed of an output shaft (output shaft 5) of the automatic transmission 2 to detect a vehicle speed VSP are provided. Have been. Here, the control unit 50
Is configured to estimate and calculate the running resistance of the vehicle and change the standard shift characteristics based on the estimation result. still,
It is assumed that the change of the standard shift characteristic includes a correction of a shift speed according to the standard shift characteristic, a selection of a shift pattern (shift map) according to running resistance, and the like.

The flowchart of FIG. 2 shows how the control unit 50 estimates the running resistance. In step 1 (shown as S1 in the figure, the same applies hereinafter), the vehicle speed VSP and the throttle opening are set. Read TVO.
In step 2, the current acceleration resistance (RESI-A) is obtained.
The current acceleration resistance (RESI-A) can be obtained by the following equation.

RESI-A = ALF × kα where ALF is a current acceleration, and kα is an acceleration resistance calculation constant set by vehicle weight or the like. In step 3, the current vehicle speed VSP is referred to by referring to a table (see FIG. 3) in which air resistance + rolling resistance RESI-RL is stored in advance corresponding to the vehicle speed VSP.
Calculate the air resistance + rolling resistance RESI-RL corresponding to.

In step 4, the current turbine rotation speed Nt (ie, the output shaft rotation speed of the torque converter 3) is determined. The turbine rotation speed Nt can be obtained by the following equation. Nt = VSP × kNt (g) Here, g indicates the current shift speed, and kNt (g) is a constant determined from the current shift speed. The current gear position may be detected by providing a gear position sensor 9 for detecting the gear position position in the transmission gear mechanism 4, but may be determined from the current gear shift instruction signal of the control unit 50 or the like. good.

In step 5, a map (see FIG. 4) in which the turbine torque Tt is stored in advance according to the turbine speed Nt and the throttle opening TVO representing the engine load is referred to, and the current turbine speed Nt and the throttle A turbine torque Tt corresponding to the opening TVO is calculated. In step 6, the current driving force FCE is obtained from the following equation.

FCE = Tt × kTt (g) Here, g indicates the current gear position, and kTt (g) is a constant determined from the current gear position. In step 7, the running resistance RESI-I (running resistance equivalent value) is obtained from the following equation.

RESI-I = (FCE)-(RESI-RL)-(RESI-A) Since the running resistance RESI-I corresponds to the slope resistance, the slope is determined as the running resistance equivalent value. The configuration may be used, and the calculation method and the type of the running resistance are not limited as long as the running resistance is estimated and calculated based on the engine load. In the present embodiment, the engine load is represented by the throttle opening, but a parameter other than the throttle opening may be used.

As described above, the control unit 50 estimates the running resistance RESI-I based on the driving force FCE calculated based on the throttle opening TVO, but when the engine load suddenly changes (particularly when the engine load suddenly increases). Is the error of the driving force FCE (FIG. 6)
The shaded area in the figure corresponds to the error) and the running resistance
Since the estimation accuracy of the RESI-I deteriorates, the estimation calculation of the running resistance is stopped as shown in the flowchart of FIG. 5 to prevent the shift characteristic from being inappropriately controlled based on the incorrect estimation result. It has become.

In order to stop the calculation of the running resistance, the calculation process of the running resistance RESI-I is not executed, and the estimated value of the running resistance is held at the value immediately before the stop and used for speed change control. Or that the calculated running resistance is not used for speed change control or the like, and in the case of a configuration in which the calculated running resistance is used as a weighted average, the weight in the weighted average is changed to This also includes reducing the degree of influence of the operation value. Further, the control using the running resistance is not limited to the shift control.

The routine shown in the flowchart of FIG.
First, in step 11, a timer TM for controlling the suspension of the estimation of the running resistance is set.
Subtract R. In the next step 12 reads the throttle opening TVO _NEW detected to date, at step 13, read the previous value TVO _OLD is the throttle opening TVO read in the previous execution of this routine.

In step 14, the previous value TVO _OLD is subtracted from the latest opening TVO _NEW to obtain a change amount ΔTVO (ΔTVO
= TVO _NEW -TVO _OLD ). The change amount Δ
TVO is the throttle opening change amount ΔTVO per execution cycle (unit time) of this routine. In step 15, it is determined whether or not the change amount ΔTVO is equal to or greater than a positive determination level DTH. Since the change amount ΔTVO is calculated as a negative value when the throttle opening TVO (engine load) is decreasing, the change amount ΔTVO
When O is equal to or higher than the positive determination level DTH, it means that the throttle opening TVO is increasing and changing at a speed higher than a predetermined speed, in other words, the engine load is rapidly increasing.

Then, at step 15, ΔTVO ≧ DTH
If it is determined that the
The opening T just before the throttle opening TVO (engine load) suddenly increases
VO _BASEFirst stop time TM1 is stored in advance corresponding to
Opening TVO just before the sudden increase_BASECompatible with
First stop time TM1 to be set is set. Here, before the surge
Throttle opening TVO_BASEIs smaller, the first
The stop time TM1 is now set to a longer time
ing.

For example, even during the same rapid opening operation up to full opening, the time during which the accuracy of estimating the running resistance deteriorates differs between the case of opening from the intermediate opening to the full opening and the case of opening from the full closing to the full opening. Generally, the estimation accuracy recovers from the intermediate opening in a shorter time. Therefore, as described above, as the throttle opening TVO _BASE before the rapid increase is smaller, a longer time is set as the first suspension time TM1 to avoid performing the estimation calculation when the estimation accuracy is deteriorated,
It is possible to prevent the estimation calculation from being uselessly stopped.

In the next step 17, the timer TMR
, The first suspension time TM1 is set, and this routine is terminated as it is. That is, when the throttle opening TVO (engine load) suddenly increases, the calculation of the running resistance is not performed by ending the present routine bypassing the calculation of the running resistance in step 23. On the other hand, in step 15, Δ
It is determined that TVO <DTH, and the throttle opening TV
O is decreasing or the throttle opening TVO
When is approximately stable, the process proceeds to step 18.

In step 18, the latest opening TVO
_NEW (Specifically, the opening TV after the sudden change stops
O) and the deviation from the opening TVO _BASE immediately before the rapid increase (TVO _NEW
−TVO _BASE ), a second suspension time TM2 corresponding to the deviation between the latest opening TVO _NEW and the opening TVO _BASE immediately before the rapid increase is set by referring to a table storing the second suspension time TM2 in advance. .

Here, the second stop time TM2 has a large deviation between the latest opening TVO _NEW and the opening TVO _BASE immediately before the rapid increase, and the opening T which suddenly increases from the initial opening TVO _BASE.
In the case where it is held by VO, it is set to a long time, and conversely, the deviation between the latest opening TVO _NEW and the opening TVO _BASE immediately before the rapid increase is small, and immediately after the throttle is greatly opened, the throttle is closed. In the event that a revert operation is performed,
Set to a relatively short time. This is because when the throttle is rapidly opened and held at the high opening side, the estimation accuracy is deteriorated for a long time, whereas when the operation is returned to the closed side after the rapid opening operation, the estimation accuracy is relatively quick. To recover.

In step 19, the second suspension time TM2
And the timer TMR, and when the timer TMR is longer than the second suspension time TM2, the step
Proceeding to 20, the second suspension time TM2 is set in the timer TMR, and if the timer TMR is shorter, the process proceeds to step 21 without updating the timer TMR. And
In step 21, it is determined whether or not the timer TMR has been decremented to 0. If the timer TMR has not been decreased to 0, that is, it is determined that the estimation calculation is to be stopped based on the stop times TM1 and TM2. At this time, by ending this routine as it is, the estimation of the running resistance is continuously stopped when the throttle opening TVO increases rapidly.

On the other hand, when it is determined in step 21 that the timer TMR is 0, it is determined that a sufficient time has elapsed after the rapid opening operation of the throttle, and that the running resistance can be estimated with high accuracy. , sets the latest opening TVO _NEW in opening TVO _{BA SE} at step 22, to update the opening TVO _BASE until an operation for rapidly increasing again throttle opening TVO is carried out, in step 23, the Figure 2 The running resistance estimation calculation shown in the flowchart is executed.

It should be noted that the timer TMR is kept at 0 by performing the processing in step 22. Thus, than the first suspension time TM1 which is set according to the level of the previous surge in throttle opening TVO, a second suspension time is set based on the latest opening TVO _NEW after surge stop T
If M2 is shorter, the shorter second suspension time TM2
Based on the above, the estimation of the running resistance is stopped.

For example, when the throttle opening TVO is suddenly greatly increased from the fully closed state, the first suspension time TM1
Although a relatively long time is set, if an operation is performed such that the throttle is rapidly opened and then immediately closed, the latest opening TVO _BASE is stored in the immediately preceding opening TVO _BASE which is fully closed.
_A relatively short time is set as the second suspension time TM2 because _NEW approaches. As a result, the throttle opening T
An operation of rapidly opening the VO is performed, and the first suspension time T
Even if a long time is set as M1, the stop time TM is corrected to be shorter by a subsequent closing operation.

In the case where the operation for rapidly increasing the throttle opening TVO is performed and the throttle opening TVO is maintained at the high opening side, the estimation of the running resistance must be stopped for the first stop time TM1. If the closing operation is performed immediately after the operation of rapidly increasing the opening TVO, the running resistance can be estimated with necessary and sufficient accuracy within a time shorter than the first suspension time TM1, as described above. And let the shorter one be selected.

Even when the throttle opening (engine load) changes suddenly even when the throttle opening changes rapidly, the necessary and sufficient estimation accuracy can be secured (see FIG. 6). Immediately thereafter, the calculation for estimating the running resistance is stopped. In the above description, it is determined whether or not the engine load is suddenly changed on the basis of the throttle opening change amount ΔTVO per execution cycle (unit time) of the routine shown in the flowchart of FIG. It is also possible to measure the time required to change by a degree, compare the measured time with a reference time as a determination level, and determine a sudden change in the engine load, or an arbitrary time frame. The change amount ΔTVO within the range is obtained, and the change amount ΔTV
If the time frame for obtaining O is different, the change amount ΔTVO may be converted into a unit time value and compared with the determination level.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an internal combustion engine for a vehicle according to an embodiment.

FIG. 2 is a flowchart showing a state of estimating running resistance in the embodiment.

FIG. 3 is a diagram showing a table of air resistance + rolling resistance in the embodiment.

FIG. 4 is a diagram showing a turbine torque map in the embodiment.

FIG. 5 is a flow chart showing control for stopping estimation of running resistance in the embodiment.

FIG. 6 is a diagram showing a correlation between a change in engine load (throttle opening) and an estimation error of a driving force.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Automatic transmission 3 Torque converter 4 Transmission gear mechanism 7 Throttle sensor 8 Vehicle speed sensor 50 Control unit

Claims (4)

[Claims] A vehicle running resistance detecting device for calculating a running resistance equivalent value of a vehicle based on at least a parameter including an engine load, wherein it is determined whether or not the engine load is suddenly changed. A running resistance detection device for a vehicle, wherein the calculation of the running resistance equivalent value is stopped for a predetermined stop time, and the stop time is changed according to the engine load before the sudden change. 2. A vehicle running resistance detecting device which calculates a running resistance equivalent value of a vehicle based on at least a parameter including an engine load, wherein it is determined whether or not the engine load is suddenly changed. A vehicle configured to suspend the calculation of the running resistance equivalent value for a predetermined suspension time and to change the suspension time according to the engine load before the sudden change and the latest engine load. Running resistance detection device. 3. A running resistance detecting device for a vehicle, which calculates a running resistance equivalent value of a vehicle based on at least a parameter including an engine load, wherein it is determined whether or not the engine load is suddenly changed. The calculation of the running resistance equivalent value is stopped for a predetermined stop time, and a first stop time is set according to the engine load before the sudden change, and the engine load before the sudden change and the latest engine load are set. A second suspension time is set in accordance with the following formula, and the calculation is suspended based on a comparison between the first suspension time and the second suspension time. . 4. The method according to claim 1, wherein a shorter one of the first suspension time and the second suspension time is selected, and the calculation of the running resistance equivalent value is suspended based on the selected suspension time. The vehicle running resistance detecting device according to claim 3.