JPH06344802A - Car constant speed running controller - Google Patents

Abstract

(57) [Abstract] [Purpose] In a vehicle equipped with an electronically controlled automatic transmission, the torque is estimated, the road gradient and the vehicle weight are obtained from this with high accuracy, and if the constant speed running control mode is selected, A vehicle that uses this road gradient and vehicle weight information to perform constant-speed traveling control actuators and gear shift control of an automatic transmission to realize comfortable constant-speed traveling at any vehicle weight and any road gradient To provide. [Structure] Means for estimating road gradient and vehicle weight by calculation, vehicle speed detection means, constant speed travel instruction operation means, constant speed travel calculation processing means, constant speed travel control drive means, and this constant speed travel control And at least one electronic control unit that controls the automatic transmission and the engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant-speed running control system for an automobile equipped with an automatic transmission, and in particular uses both output control of an engine and shift control of an automatic transmission in response to changes in road gradient. To achieve optimum constant speed running.

[0002]

2. Description of the Related Art As a conventional example of this type, as described in Vol.46, No.2,1992 of the Automotive Engineering Society,
In addition to the direct drive by the accelerator pedal of the throttle valve that controls the amount of air drawn into the engine, the addition of an indirect drive actuator and the addition of an electronic control device that outputs a drive signal to this actuator will control the conventional constant speed travel. The device is configured. In addition to the vehicle speed signal, this electronic control unit receives an operation signal operated by the driver to start the operation of the constant speed traveling control and a cancel signal to end the operation. When the operation signal is input, the actual vehicle speed is controlled by the actuator so as to be the same as the set vehicle speed. However, it becomes difficult to maintain the set vehicle speed only by the control by the actuator when the vehicle is climbing uphill with a lot of luggage, and recently, shift control of the automatic transmission has been added. Came. For example, when traveling uphill from a flat road while traveling at a constant fourth speed, the actual vehicle speed gradually decreases. Therefore, the throttle valve is opened by a predetermined amount by the actuator to control the actual vehicle speed to approach the set vehicle speed. However, under conditions such as a steep slope and a high vehicle weight, even if the throttle valve is fully opened. The result is that the vehicle speed does not reach the set vehicle speed and the vehicle departs from the set vehicle speed. In this case, the automatic transmission is downshifted to the third speed, the driving force of the wheels is increased, and the actual vehicle speed is controlled to approach the set vehicle speed. However, when the road becomes flat again after that, there is too much driving force at the third speed and the engine speed is too high, so it is necessary to return to the fourth speed. Therefore, in the conventional system, a control is added such that a third speed is set for 20 seconds, for example, by a timer. However, in this case, if the steep slope continues as it is, the shift is repeated 4⇒3⇒4⇒3⇒4, resulting in a so-called busy shift, and the occupant feels discomfort. Therefore, in the above-mentioned known example, the fuzzy control technique is applied to estimate the load state of the engine, that is, the gradient from the movement of the throttle opening and the vehicle speed, and optimally control the return timing from the third speed to the fourth speed. It is incorporated in the constant speed electronic control unit.

[0003]

In order to apply fuzzy control to the above-mentioned complicated control, it is indispensable to put a fuzzy chip into practical use capable of high-speed calculation. However, at present, it is insufficient for automobiles in terms of cost, environment resistance, and degree of integration of functions, and improvement is desired.

[0004]

According to the present invention, the engine torque characteristic and the torque converter characteristic are controlled by an electronic control unit for automatic transmission control without estimating the road gradient by fuzzy control in the constant speed electronic control unit. The driving torque of the driving wheels, the flat running resistance torque, the gradient running resistance torque, and the acceleration running resistance torque are estimated by using this to obtain the road gradient and the vehicle weight with high accuracy, and the constant speed running control mode is selected. Then, by utilizing the road gradient and vehicle weight information, the constant speed traveling control actuator and the gear shift control of the automatic transmission are executed.

[0005]

By configuring the above means, the actual vehicle speed of the vehicle can be always made to follow the predetermined vehicle speed regardless of the size of the vehicle and any change in the road gradient. The person can obtain a comfortable running sensation.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram of the present invention. 1 is an engine, 2 is an automatic transmission (AT), 3 is a propeller shaft, 4 is a differential device also serving as a final reduction gear, 5 is drive wheels, 6
Is an AT hydraulic circuit, and 7 is a microcomputer built-in A
T control unit (electronic control unit), referred to herein as ATCU. Reference numeral 8 denotes a control unit (electronic control device) for an engine with a built-in microcomputer, which is referred to as an ECU here. Reference numeral 9 is an air cleaner, 10 is an air flow sensor, 11 is a throttle chamber, 12 is an intake manifold, and 13 is an injector for injecting fuel. The inside of the AT is further divided into a torque converter 14 and a gear train 15. A turbine sensor 16 for detecting the output shaft speed of the torque converter 14, that is, the mission output shaft speed, and a mission output for detecting the mission output shaft speed. A shaft rotation sensor 17 is attached. Information such as a crank angle sensor, an air flow sensor 10, and a throttle sensor 18 is input to the ECU 8, various calculations such as an engine speed signal are executed, and a valve opening drive signal is output to the injector 13 to control the fuel amount. Further, although not shown, various controls such as outputting an ignition signal to the spark plug to control the ignition timing are executed. On the other hand, the ATCU 7 has signals from the mission output shaft rotation sensor 17, the AT oil temperature sensor, etc., and the engine speed from the ECU 8,
A throttle opening signal and the like are input and various calculations are executed to output a hydraulic control mounted on the hydraulic circuit 6, a switching solenoid valve 20 valve opening drive signal, an ignition timing correction signal, and the like. Although not shown, the throttle valve provided in the throttle chamber 11 is opened and closed in conjunction with the accelerator pedal.
It is also opened and closed by the SCD actuator 19 (actuator for constant speed traveling control). The ASCD actuator 19 is operated and controlled by the ATCU 7.

FIG. 2 shows an example of the configuration of a control device such as the above ATCU and ECU. The control device is at least a CPU
21, a ROM 23, a RAM 24, an input / output interface circuit 26, and a bus 22 that connects them, and a LAN control circuit 25 is required when connecting the ATCU 7 and the ECU 8 with a LAN as shown in FIG.

In the configuration example of the present invention described above, ATCU and E
Although one CU is provided for each, it goes without saying that a control device in which both are integrated may be used. In this case, one CPU may be provided, or one CPU may be integrated.

FIG. 3 shows an example of the configuration of a constant speed traveling control device. The throttle valve 60 arranged in the throttle chamber 11 is opened and closed by the ASCD actuator 19 via a throttle lever 61 and a throttle wire 62 that are attached integrally with the throttle valve 60. The ASCD actuator 19 includes a negative pressure drive diaphragm device 63 and a negative pressure control solenoid 68,
It is composed of 69. The negative pressure driving diaphragm device 63 is composed of a diaphragm 64 and a spring 65. The negative force driving diaphragm device 63 has an action force determined by the product of the drag force of the spring 65 and the pressure receiving area of the diaphragm 64 and the negative pressure according to the negative pressure of the negative pressure chamber 66. The diaphragm moves to the balance point and balances. As a result, the opening degree of the throttle valve 60 is automatically determined according to the magnitude of the negative pressure in the negative pressure chamber 66. Two negative pressure control solenoids are provided, one is a negative pressure control solenoid A68 that opens and closes a communication hole 67 that communicates the negative pressure of the intake manifold 12, and the other is an opening and closing between the negative pressure chamber 66 and the atmosphere. It is composed of a negative pressure control solenoid B69. The driving signals of these two negative pressure control solenoids are calculated and processed by the constant speed traveling control electronic circuit 70 in the ATCU 7. Signals such as a vehicle speed signal VSP, an operation signal, a cancel signal, a brake SW signal, and a gradient are input to the constant speed traveling control electronic circuit 70.

Next, the torque estimation, gradient estimation and vehicle weight estimation will be described in detail. FIG. 4 is a torque estimation block diagram using an engine torque map. Engine torque map 2
At 7, the engine torque Te is obtained from the throttle opening TVO and the engine speed Ne, and the auxiliary machine torque T _ACC used in the air conditioner or the like is subtracted to obtain the input torque to the torque converter, that is, the pump torque Tp. here,
The auxiliary machine torque T _ACC is obtained by a method described later, or a representative numerical value of a predetermined torque of each auxiliary machine or a predetermined torque value of each auxiliary machine for each operating state is used. This is multiplied by the torque ratio t, the gear ratio r _{(GP) of the} block 30, and the final gear ratio r _f of the block 31 to obtain the drive torque To. The torque ratio t is a block of 28, and the slip ratio e of the torque converter is obtained from Ne and the turbine speed Nt of the torque converter, and the et characteristic diagram (block 29) stored in advance or the et characteristic is stored. Calculate using an expression.

FIG. 5 is a block diagram of torque estimation using the mechanical characteristics (torque converter characteristics) of the torque converter. N
The slip ratio e of the torque converter is obtained in block 32 from e and the turbine speed Nt of the torque converter, and the e-τ characteristic diagram stored in advance in block 33 or the e-τ characteristic equation is used to obtain (τ Is the capacity coefficient of each torque converter, which is determined by the slip ratio e) τ
Ask for. Multiplying this by the square of Ne gives the input torque to the torque converter, that is, the pump torque Tp. The driving torque To can be obtained by multiplying this by the torque ratio t obtained in the block 34, the gear ratio r _(GP) obtained in the block 30, and the final gear ratio r _f obtained in the block 31.

The above two torque estimation methods ((1) a torque estimation method using an engine torque map and (2) a torque estimation method using a mechanical characteristic (torque converter characteristic) of a torque converter) are as follows. There is a weakness.
Regarding the method (1), the accuracy of the estimated engine torque Te and the final estimated drive torque To becomes insufficient unless the accessory torque T _ACC is accurately estimated. With regard to the method (2), when the slip ratio e of the torque converter becomes large and the region becomes larger than the slip ratio e≈0.85, that is, the so-called coupling region, it is determined by the slip ratio e held by each torque converter described above. The value of the capacity coefficient τ changes rapidly, and the pump torque Tp cannot be estimated with sufficient accuracy, that is, the final drive torque To cannot be estimated.

Therefore, in order to cover these weak points,
It is more desirable to use a torque estimation method switching formula as shown in FIG. That is, for example, the slip ratio e≈0.
It is said that the torque is estimated with the method of (2) in the area below 9 and the method of (1) in the area above 9 as a boundary. Here, accessory torque T
_{The ACC} can be estimated by learning the accessory torque T _ACC at a point of slip ratio e≈0.85, for example. Block 35
Then, the auxiliary machine torque T _ACC is calculated from the pump torque Tp calculated from the pump torque estimation unit 36 and the engine torque Te calculated from the engine torque estimation unit 37 at this point as T _ACC = Te−Tp (1) , Next, until the learning point of slip ratio e≈0.85 comes, T _ACC
The value of is stored as the auxiliary machine torque, and T is stored by the method of (1) above.
It may be used when estimating o. This torque switching is performed in block 38. This switching is done in block 32.
From the coast, emblem, and lockup determination section of the block 39. E ≦, not the coast, emblem, or lock-up operation range
If 0.9, the Tp obtained in block 36 is used. E, not coast, emblem, or lockup areas
If> 0.9, Tp determined from blocks 37 and 35 is used. On the other hand, regardless of the magnitude of the slip ratio e, the block 37,
The Tp obtained from the block 35 is used. In the coast / emble operation area, switching is performed to use Tp from the block 40. Since it is desirable that the learning of the accessory torque T _{ACC in} the learning unit 35 is not performed during the shift, the block 41 determines whether the shift is in progress. This includes
This is done from the signals of CURGP (current gear position) and NXTGP (gear position to be changed).

FIG. 7 shows a block diagram for estimating the road gradient θ _t using any of the drive torque estimations of FIGS. 4 to 6. The block 42 corresponds to any of the drive torque estimation units of FIGS. 4 to 6. Here, the driving force F _O of the wheel
Is equal to the sum of the running resistance F _R , the acceleration resistance F _α , and the gradient resistance F _θ. F _O = F _R + F _α + F _θ (2) Here, each term on the right side can be expressed as follows.

F _R = F _r + F _A (3) F _r = μ _r · W · g (4) F _A = μ ₁ · A · V ² (5) F _θ = W · g · sin θ _t (6) F _α = (W + Wr) · α (7) F _r ; Rolling resistance F _A ; Air resistance F _R ; Running resistance F
_α : Acceleration resistance F _θ ; Gradient resistance μ _r ; Rolling resistance coefficient μ ₁ ; Air resistance coefficient W; Vehicle gross weight g; Gravity acceleration A; Vehicle front projected area V; Vehicle speed Wr; Rotating part equivalent weight α; Therefore, if equation (2) is rewritten with torque, To = T _R + T _α + T _θ (8) Therefore, T _θ becomes T _θ = To−T _R −T _α (9). The gradient θ _t can be obtained by converting the equation (6) to obtain θ _t = arcSIN (T _θ / (W · g · R) (10). Further, T _R and T _α are T _R = R · (F _r + F _A ) ... (11) T _α = R · F _α = R · (W + Wr) · α (12) In the block 43, the equations (11), (4), and (5) are used. Level running torque T _R is obtained by
6 is used for α in equation (12), and block 46 is used for α in equation (12).
Other portions are obtained, and in block 51, the acceleration torque T _α is obtained from both. Seeking T _theta according (9) in block 47, further a stable T _theta via a low pass filter (LPF) 48, block 49 calculates the road gradient theta _t by calculating the block 50 (10) be able to. The road gradient θ _t obtained here is temporarily stored in the RAM.

FIG. 8 shows a vehicle weight estimation block diagram. The description is partially duplicated with the block shown in FIG. 7. To obtained by the output shaft torque estimating unit 42 and T _R obtained by the flatland running resistance estimating unit 43, block 42 in FIG.
Based on T _θ obtained by the gradient resistance estimation unit 52 including 43, 47, and 48, the following formula obtained by transforming the formula (8) in the block 54 is given by: T _α = To−T _R −T _θ (13) Acceleration resistance The torque T _α is calculated. Blocks 44 and 4 of FIG.
5 is multiplied by α obtained by the vehicle longitudinal acceleration estimation unit 53 including 5 and the tire radius R from the block 55,
It is said that W + Wr is calculated in the block 57 from the following formula W + Wr = T _α / R · α (14) obtained by converting the formula (12), and the previously stored Wr is subtracted in the block 58 to calculate the vehicle weight W. It is a thing. The vehicle weight W obtained here is temporarily stored in the RAM and is used next time to calculate T _R and T _θ .

The road gradient θ stored as described above
_{The t} and the vehicle weight W are used as follows when the vehicle enters the constant speed running mode.

FIG. 9 shows a constant speed traveling control flow. In block 71, the driver operates the operation button to set the constant speed traveling mode, and when the operation signal is turned on, in block 72, the set vehicle speed (VSP) _O is set. In block 73, calculates the deviation ΔV of the (VSP) _O and the current actual vehicle speed VSP. In block 74, in the case of overdrive OD, that is, in the case of four forward speeds, it is determined whether or not it is the highest fourth speed (gear ratio 1 or less). Since the ATCU 7 always seeks the current gear position GP, this signal is used. If it is judged to be OD, the routine proceeds to block 75, where it is judged if the vehicle speed deviation ΔV is larger than the set allowable width ε.
If it is determined to be large, the routine proceeds to block 76, where the road gradient θ _t and vehicle weight W previously stored are read. Then, the process proceeds to block 77, and the control gain value k mapped by θ _t and W shown in FIG. 10A is searched and extracted. Then, the process proceeds to block 78, where ΔV and the control gain value k
And the product is taken as ΔTVO for throttle opening correction. In block 79, the sum of this ΔTVO and the current TVO is taken, and this is made a new TVO. And block 80
Then, it is determined whether this TVO is smaller than the set value c. It is desirable to set the set value c near the fully open position. If it is determined that it is not near full opening, the routine proceeds to block 81, where the throttle opening correction amount ΔTVO is controlled.
When TVO is judged to be larger than the set value c, block 82
Proceed to step 3 and shift down for the third speed. Block 81,
After passing 82, the process returns to block 73 again. The map search for the control gain value k in the block 77 after downshifting to the third speed uses the map for the third speed in FIG. 10B. Figure 1
In both 0 (a) and (b), the control gain value k is set to a larger value as θ _t and W are larger.

If it is determined at block 74 that it is not OD, the routine proceeds to block 83, where the road gradient θ _t is read. Here, as described in detail with reference to FIG. 7, θ _t is calculated by calculation every moment, and the latest data is read. And block 8
Then, the routine proceeds to step 4 to judge whether or not this θ _t is smaller than the set value d. This set value d is set near the slope of the flat road. θ
_{If it} is determined that _t is smaller than the set value d, that is, it is close to a flat road, the routine proceeds to block 85, where the fourth speed upshift is executed. Then, the process returns to block 73 again.

When it is judged at block 75 that the vehicle speed deviation ΔV is smaller than the set allowable width ε, the routine proceeds to block 86, at which it is judged whether the vehicle speed deviation ΔV is positive or negative. If negative, block 76
Return to immediately. If it is positive, that is, ε ≧ ΔV ≧ 0, it is determined that the vehicle speed is within the set allowable range, and the current control of maintaining ΔTVO is executed in block 87.
Then, the process returns to block 73 again.

When it is determined in block 84 that θ _t is larger than the set value d, that is, it is determined that the vehicle is still traveling on an uphill slope, and the routine proceeds to block 88, where the current gear position GP (3rd speed)
, And returns to block 75.

Next, the ΔTVO control in block 81 will be described in detail. ΔTVO can take positive and negative values, as is apparent from blocks 75, 86 and 78. When ΔTVO is positive, that is, when ΔTVO is further opened from the current opening, the negative pressure control solenoid B69 in FIG. 3 is operated to cut off the communication of the negative pressure chamber 66 with the atmosphere to reduce the negative pressure of the negative pressure chamber 66. The throttle valve is opened further by raising it. Δ
When TVO is negative, that is, when the current opening is closed by ΔTVO, the operation of the negative pressure control solenoid B69 in FIG. 3 is stopped, the negative pressure chamber 66 is communicated with the atmosphere, and the negative pressure in the negative pressure chamber 66 is reduced. The throttle valve is controlled in the closing direction by lowering it. The negative pressure control solenoid A68 is block 7
When the operation signal of No. 1 is turned on, it operates and connects the communication hole 67 and the negative pressure chamber 66.

The control flow shown in FIG. 9 is immediately stopped when a cancel signal is input. Further, even when the ON signal of the brake SW is input, the execution is temporarily stopped, and when the driver tries to return by operating the operation button, the control flow shown in FIG. 9 is executed again.

[0024]

As described above, according to the present invention, the actual vehicle speed of an automobile can always be made to follow a predetermined set vehicle speed regardless of the size of the vehicle weight and any change in the road gradient. Can get a comfortable driving feeling.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of the present invention.

FIG. 2 is a configuration diagram of a control device.

FIG. 3 is a diagram showing a constant speed traveling control device.

FIG. 4 is a block diagram of torque estimation using an engine torque map.

FIG. 5 is a torque estimation block diagram using torque converter characteristics.

FIG. 6 is a block diagram of a torque estimation method switching type.

FIG. 7 is a gradient estimation block diagram.

FIG. 8 is a vehicle weight estimation block diagram.

FIG. 9 is a constant-speed traveling control flowchart.

FIG. 10 is a diagram showing a control gain k map.

[Explanation of symbols]

1 ... Engine, 2 ... AT, 7 ... ATCU, 8 ... ECU,
Reference numeral 19 ... ASCD actuator, 42 ... Driving torque estimating unit, 43 ... Flatland running resistance torque estimating unit, 50 ... Gradient estimating unit, 51 ... Acceleration running resistance torque estimating unit, 58 ... Vehicle weight estimating unit.

Claims (1)

[Claims] 1. A system comprising at least one electronic control unit for controlling electronic control of an engine and an automatic transmission, wherein a first estimating means for estimating a driving torque of a driving wheel and a flatland running resistance torque are estimated. Second estimating means, a third estimating means for estimating the gradient traveling resistance torque, a fourth estimating means for estimating the acceleration traveling resistance torque, and means for estimating the road gradient from the four estimating means, It has means for estimating the vehicle weight from the four estimating means, constant speed traveling instruction operating means, constant speed traveling calculation processing means, and constant speed traveling control driving means, and the road gradient obtained by the means and the vehicle A vehicle constant speed traveling control device, characterized in that the constant speed traveling control drive means is controlled using weight information.