JP2000027988A - Engine control device and motor vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To regularly ensure the gear shift control of a transmission precisely reflecting the intension of a driver by providing a means for determining the torque of an engine, and determining the intended change gear ratio of an automatic transmission from the resulting torque and the traveling speed. SOLUTION: This device is provided with an acceleration detecting means 1 formed of an acceleration sensor to detect the traveling directional acceleration (a) of a motor vehicle. A change gear ratio arithmetic means 3 is formed of a microcomputer, which arithmetically detects the torque of an engine from the acceleration (a) and calculates the change gear ratio from a change gear ratio map by use of this torque and the vehicle speed V detected by a vehicle speed detecting means 2 as retrieval inputs. According to this structure, since the gear shift is performed according to the engine torque, the point of switching the change gear ratio is changed even in the same throttle opening. Consequently, a precise gear shift can be automatically obtained according to the operating state where the shift-up is delayed according to the magnitude of the traveling load even under the same change gear pattern, and the improvement in operability and the improvement in fuel consumption can be reconciled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile equipped with a speed change mechanism and a control apparatus therefor, and more particularly to an engine control apparatus suitable for controlling an automatic transmission of an automobile equipped with a torque converter, and an engine control apparatus provided with the same. Car related.

[0002]

2. Description of the Related Art Conventionally, a shift control device for an automatic transmission detects a vehicle speed and a throttle opening as an electric signal as described in, for example, Japanese Patent Application Laid-Open No. 61-226706.
With the vehicle speed and the throttle (valve) opening as variables, a predetermined gear (ratio) corresponding to the current vehicle speed and the throttle opening is selected based on a preset shift pattern. And the shift pattern at this time is
For example, a plurality of types such as an economy traveling pattern and a sporty traveling pattern are set, and are switched by a driver's pattern selection operation.

[0003]

In the above prior art, no consideration is given to a sufficient reflection of the driver's intention in the gear ratio control, and the control of the gear ratio is performed according to the gear pattern selected at that time. Since it is almost uniquely determined, a shift that accurately reflects the driving situation cannot be obtained as it is, and for that purpose, the driver has to frequently perform relatively troublesome shift pattern selection switching operations. ,
There was a problem that operability was not good.

SUMMARY OF THE INVENTION It is an object of the present invention to ensure that the speed change control of the transmission, which accurately reflects the driver's intention, is always obtained without requiring extra driving operation, and that the operability is sufficiently improved. To provide an engine control device and an automobile.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an engine control apparatus for an automobile equipped with an automatic transmission, a means for determining the torque of the engine, a means for determining the traveling speed of the automobile, This is achieved by including means for determining a target gear ratio of the automatic transmission from speed, and means for outputting the target gear ratio to the automatic transmission.

[0006] Further, the object of the present invention is to provide an automobile having an automatic transmission and a control device for controlling the automatic transmission, wherein the control device includes a means for determining an engine torque and a means for determining a running speed of the vehicle. Means for obtaining a target gear ratio signal of the automatic transmission from the torque and the traveling speed; and means for outputting the target gear ratio signal to the automatic transmission, wherein the automatic transmission comprises the target gear ratio. It is achieved to have means for controlling to the target gear ratio given by the signal.

The gear ratio stage is calculated not by the accelerator opening but by the torque of the engine. Here, the engine torque corresponds to the driving state expected by the driver, rather than the accelerator opening. That is, even with the same accelerator opening, the engine torque shows a different rise due to differences in vehicle weight, road surface resistance, etc.,
For example, when the vehicle weight is large, even under the same shift pattern, the shift-up time point is delayed as compared with the case of the accelerator opening degree, so that the gear ratio control corresponding to the actual driving state can be sufficiently obtained. Will be.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an engine control device and an automobile according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an acceleration detecting means, 2 denotes a vehicle speed detecting means, 3 denotes a gear ratio calculating means, and 4 denotes an automatic transmission.

The acceleration detecting means 1 comprises an acceleration sensor or the like, and has a function of detecting the acceleration a in the traveling direction of the automobile.

The vehicle speed detecting means 2 comprises a sensor for detecting the rotational speed of the propeller shaft of the vehicle, and functions to detect the running speed of the vehicle, that is, the vehicle speed V.

The gear ratio calculating means 3 comprises a microcomputer, and has a function of calculating and detecting the engine torque Te from the acceleration a, and a gear ratio map using the torque Te and the vehicle speed V as search inputs. It works to calculate.

The automatic transmission 4 is composed of a torque converter, a planetary gear mechanism, and the like, and functions to switch the speed ratio of a drive system between the engine and the traveling wheels according to a control signal supplied from the speed ratio calculating means 3.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

The process according to the flowchart of FIG.
The microcomputer in the speed ratio calculating means 3 is configured to be executed at a predetermined fixed time interval by, for example, a timer interrupt or the like. The vehicle speed V is read, and then the acceleration a from the acceleration detecting means 1 is read in step 21. Further, at step 22, the current gear ratio, that is, the current value i of the gear ratio, is read from the automatic transmission 4.

Next, at step 23, the engine torque Te at this time is calculated from the acceleration a and the current value i of the gear ratio. That is, Te = F (a, i) is calculated. It should be noted that the torque Te may be obtained by using a torque map in which a and i are used as search inputs, and performing a search process on this map.

In step 24, using the speed ratio map shown in FIG. 3, it is determined whether or not the speed ratio needs to be changed at this time based on the torque Te, the vehicle speed V, and the current value i of the speed ratio. If it becomes necessary, a new speed ratio i 'is output to the automatic transmission 4 in step 25, and the process is terminated.

As described above, in the control of the conventional automatic transmission, only the vehicle speed and the throttle opening are used as variables, and a predetermined gear ratio is selected based on a predetermined gear shift pattern. Therefore, in this method, it is difficult to perform an accurate shift with respect to a change in driving conditions, particularly a change in running load. For example, on flat roads and gentle downhills, shifting up earlier than on an uphill is thought to improve fuel economy without impairing drivability, but in the past, shifting was performed by accelerator opening and vehicle speed. Therefore, the shift pattern, specifically, the gear ratio map as shown in FIG. 3 (the vertical axis is the throttle opening)
Without changing the gear, such a shift cannot be performed.

However, in this embodiment, the shift is performed in accordance with the engine torque. Therefore, even when the throttle opening is the same, the point in time at which the gear ratio switches is changed. Shifting up is slower when the driving load is heavy, and earlier when the running load is lighter, so that an accurate shift can be automatically obtained according to the driving situation, improving both drivability and fuel efficiency. Can be easily achieved.

In this embodiment, the torque of the engine is calculated and detected based on the acceleration in the traveling direction of the vehicle detected by the acceleration detecting means 1. Therefore, a special torque sensor is not required, and the cost is increased. However, it is a matter of course that a torque sensor is used in place of the acceleration detecting means 1 to directly detect the engine torque and to execute the speed ratio calculating means 3.
Needless to say, it may be input to

FIG. 4 shows another embodiment of the present invention. In the drawing, reference numeral 5 denotes an engine speed detecting means which, as the name implies, functions to detect the engine speed Ne.
For example, the engine speed Ne is detected by counting pulses from a pulse generator called a crank angle sensor or the like attached to the crankshaft of the engine.

Therefore, the embodiment of FIG. 4 is different from the embodiment of FIG. 1 in that an engine speed detecting means 5 is provided instead of the vehicle speed detecting means 2, and the engine speed is not the vehicle speed V but the engine speed. The only difference is that the gear ratio is calculated from the engine speed Ne and the engine torque Te using Ne.

Next, the operation of the embodiment shown in FIG.
This will be described with reference to the flowchart of FIG.

The processing according to the flowchart of FIG.
The microcomputer in the speed ratio calculating means 3 is configured to be executed at a predetermined constant time interval by, for example, a timer interrupt or the like. When the process starts, first, in steps 50, 51, and 52,
The engine speed Ne, the acceleration a, and the current gear ratio i of the automatic transmission 4 are sequentially read, and the engine torque Te is calculated from these data in step 53. Note that the above steps 51 to 53
Are performed in steps 21 and 2 in the embodiment of FIG.
3 is the same as the processing in step 3.

In the following step 54, it is determined whether or not the detected engine torque Te indicates a finite value. If the result of this determination is NO, that is, if it is determined that the engine torque Te is zero, it means that there is no need to change the gear ratio, so at this time the routine proceeds to step 55, where the current gear ratio i is maintained. Then, the process ends.

On the other hand, if the decision result in the step 54 is YE
S, that is, when it is determined that the engine torque Te is a finite value, it means that the gear ratio needs to be changed. In this case, the process proceeds from step 56 to step 57 and step 60 via step 58, and proceeds to step 60. It is determined whether the change of the gear ratio required at this time is in the upshift direction or the downshift direction. Note that, here, the engine torque Te is a detection result of the torque by the acceleration detecting means 1. Therefore, even when the detection result that the engine torque Te is 0 is obtained, the actual engine torque is 0. Does not necessarily mean

First, at step 56, the current vehicle speed Vsp
[Km / h] is calculated from the current engine speed Nenew [rpm], the current gear ratio i, the final speed reduction ratio iend, and the outer diameter L [m] of the traveling drive wheel (tire) by the equation (1).

Vsp = (Nenew) / (i × iend) × L × (60) / (1000) (1) Next, in step 57, the engine torque Te is
The target engine speed Netar [rpm] is calculated by the equation (2). This may be calculated by a search using a map shown in FIG. 6, which will be described later.

Netar = 1 / k × Te (2) k: proportionality constant In step 58, the target engine speed Netar, the current vehicle speed Vsp, the final reduction ratio iend, and the traveling drive wheels are further calculated. The target speed ratio iter is calculated from the outer diameter L of the (tire) by the equation (3).

Itar = (Netar) / (Vsp × iend) × L × (60) / (1000) (3) Then, in step 59, the target gear ratio i thus obtained is obtained.
From tar and the current gear ratio i, it is determined whether the change of the gear ratio required at this time is in the upshift direction or the downshift direction.

Here, the automatic transmission 4 (FIG. 4) is a four-speed transmission and has four types of speed ratios, ie, first gear: i ₁ , second gear:
i _2, 3 speed: i _3, 4-speed: assumed with i _4, in which the step 59, performs the following four determination, to determine a new gear ratio i '. That is, the new gear ratio i ′
Is a determination as to whether it is in the upshift direction or the downshift direction.

Itar> i ₁ ⇒ i ′ = i ₁ i ₁ ≧ itar> i ₂ ⇒ i ′ = i ₂ i ₂ ≧ itar> i ₃ ⇒ i ′ = i ₃ i ₃ ≧ itar> i ₄ ⇒ i ′ = i ₄ Then, in step 60, the new speed ratio i ′ determined in this way is output to the automatic transmission 4, and the process ends.

When the result is YES, that is, in the upshift direction, the routine proceeds to step 57, where a shift map shown in FIG. 6 is searched, and the engine speed Ne at this time and the current gear ratio i of the automatic transmission 4 are determined. And the engine torque Te
, A new speed ratio i ′ is obtained from the above, and is output to the automatic transmission 4 in step 59 to terminate the process. On the other hand, when it is determined in step 56 that the gear is in the downshift direction, the process proceeds to step 58, where Of the gear ratio I of I = g (N
e, Te, i) are calculated, and similarly in step 59
To output to the automatic transmission 4 and terminate the process.

Next, a description will be given of a shift operation obtained as a result of executing the above-described process of calculating the new speed ratio i 'with reference to a shift map shown in FIG.

If, for example, the engine torque Te is at the point A, in this case, the speed is changed at an engine speed Ne of 3000 [rpm]. After the shift, the engine speed Ne decreases to a point B near 2000 [rpm],
After this, the engine speed Ne at around 3000 [rpm] A
When it rises to the point, it will operate to shift up again.

On the other hand, for example, if the current transmission ratio i of the automatic transmission 4 is the third speed and is at the point B in the figure, and the engine torque Te has increased to the point C, this means that Indicates that a large drive torque is required due to downshifting. That is, as described above, the fact that the engine torque Te has increased from the point B to the point C means that the driver depresses the accelerator pedal, and as a result, the acceleration under the current gear ratio i becomes large. This means that the engine torque Te has risen and changed.

Also at this time, a new gear ratio i 'is given by the processing in step 59, so that at this time, the gear is necessarily downshifted. That is, since the current transmission ratio i of the automatic transmission 4 in this case is the third speed, becomes D (2) points when the gear ratio i ₂ of the second speed from the engine torque Te at the point C in FIG. 6, the engine rotation Although the number Ne becomes slightly lower than 4000 [rpm], when the gear ratio i of the _first speed is set to the same value, the point E (1) is reached and the engine speed Ne is increased.
Rises to over 5000 [rpm], and it can be seen that a large acceleration force can be obtained.

Also in this embodiment, since the gear shift is performed in accordance with the engine torque, the point in time when the gear ratio is switched changes even with the same throttle opening degree. Shifting up is slower when the driving load is heavy, and earlier when the driving load is lighter, so that an accurate shift is automatically obtained according to driving conditions, making it easy to achieve both improved driving performance and improved fuel efficiency. It can be planned.

Next, still another embodiment of the present invention will be described with reference to FIG.

First, in the above embodiment, step 2 in FIG.
4 and 25, or steps 57, 58 and 59 in FIG.
As is clear from the relationship, when the gear ratio calculating means 3 determines that the gear ratio should be changed, the automatic transmission 4 immediately changes the gear ratio at that time.

However, when the gear ratio is changed when a large force (referred to as a lateral force) appears in the lateral direction, for example, when the vehicle is traveling on a sharp curve at a considerable speed, the traveling stability is reduced. It may be damaged.

Therefore, in the embodiment of FIG. 7, an acceleration sensor capable of detecting the acceleration appearing in the left-right direction of the automobile is used in the above-described embodiment, and the output a 'is output to step 7.
In step 71, a lateral force T is calculated from the acceleration output a 'by calculating T = h (a').
Further, at step 72, the absolute value | T |
Is determined whether or not exceeds a predetermined determination value s,
When the result is YES, that is, when it is determined that | T |> s, the process of step 73 is executed so that the change of the gear ratio by the automatic transmission 4 is prohibited.

Therefore, according to this embodiment, the gear ratio is not changed when a lateral force of a predetermined value or more is applied to the vehicle, for example, when passing through a sharp curve, and the running stability of the vehicle is improved. can do.

In the embodiments shown in FIGS. 1 and 4, since an acceleration sensor is already used, not only the acceleration in the running direction of the car but also the acceleration appearing in the left and right directions of the car can be detected as the acceleration sensor. Since it can be easily implemented only by using a simple sensor, there is an effect that the cost increase is small.

[0045]

According to the present invention, the gear ratio control that fully reflects the driver's intention can be obtained automatically without changing the gear ratio pattern, and the performance of the automobile is sufficiently improved. And good operability can be easily and reliably provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an engine control device according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is an explanatory diagram of a shift map used in the embodiment of FIG.

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a flowchart for explaining the operation of the embodiment in FIG. 4;

FIG. 6 is an explanatory diagram of a shift map used in the embodiment of FIG.

FIG. 7 is a block diagram showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Acceleration detecting means 2 Vehicle speed detecting means 3 Gear ratio calculating means 4 Automatic transmission 5 Engine speed detecting means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 59:44 (72) Inventor Yoshiyuki Yoshida 4026 Kuji-cho, Hitachi-city, Ibaraki Pref. (72) Inventor Noritomo Oyama 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture, Hitachi Research Laboratories, Hitachi, Ltd. (72) Inventor Yutaka Nishimura 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture, Hitachi Research Laboratory, Hitachi, Ltd.

Claims (2)

[Claims] 1. An engine control device for an automobile equipped with an automatic transmission, comprising: means for determining the torque of the engine; means for determining the traveling speed of the vehicle; and a target of the automatic transmission based on the torque and the traveling speed. An engine control device comprising: means for determining a gear ratio; and means for outputting the target gear ratio to the automatic transmission. 2. An automobile, comprising: an automatic transmission; and a control device for controlling the automatic transmission, wherein the control device includes: a unit for determining an engine torque; a unit for determining a traveling speed of the vehicle; Means for obtaining a target transmission ratio signal of the automatic transmission from the traveling speed and
An automobile having means for outputting the target gear ratio signal to the automatic transmission, wherein the automatic transmission has means for controlling the automatic transmission to have a target gear ratio given by the target gear ratio signal; .