JP2658349B2 - Engine output control device - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to an engine output control device that controls an engine output by, for example, a throttle valve.

(Prior Art) In general, an engine output control device called a drive-by-wire has been developed and is being put to practical use.

This is so that the access pedal and the throttle valve are not mechanically connected, the depression position (operation amount) of the accelerator pedal is detected, the target drive shaft torque is determined from the detected amount, and the target drive shaft torque can be obtained. Then, the throttle valve is driven by a motor.

By the way, the air that has passed through the throttle valve is mixed with fuel and enters the cylinder of the engine, where engine output is generated. In the case of an automatic transmission vehicle, this engine output is transmitted to a drive shaft via a torque converter and a transmission, and further transmitted to wheels to become a driving force.

Therefore, the power generation and transmission process in the vehicle can be divided into two stages: an intake process from the throttle valve to the engine main body, and a torque transmission process from the engine main body to the drive shaft.

(Problems to be Solved by the Invention) In the power generation and transmission process, air taken through the throttle valve is reflected on torque through a surge tank and a cycle of intake, compression, and explosion. There is a transmission delay up to

Looking at the torque transmission process, there is a transmission delay due to the torque ratio of the torque converter (that is, transient acceleration / deceleration of the rotational inertial mass due to a slip change).

Therefore, the response from the operation of the accelerator to the transmission of the torque is poor, and it is difficult to quickly exert the desired drive shaft torque.

The present invention has been made in view of the above circumstances, and aims to ensure good responsiveness up to torque transmission and to quickly and accurately exert a desired drive shaft torque. It is an object of the present invention to provide an engine output control device that can perform the control.

[Means for Solving the Problems] Means for determining a target drive shaft torque, means for determining an actual drive shaft torque transmitted to the drive shaft, actual drive shaft torque determined by this means, and the target drive Means for determining a deviation from the shaft torque, means for determining a steady engine output torque from the target drive shaft torque, means for determining a steady engine output control amount from the steady engine output torque determined by the means, and a steady engine determined by the means. Means for obtaining a target engine output control amount by feeding back the deviation with respect to the output control amount; means for adjusting the engine output control amount in accordance with the target engine output control amount obtained by the means; A mathematical model that is linear and represents the deviation from the equilibrium state, and the parameters of the mathematical model Means for determining and calculating back,
Means for setting the feedback gain by a parameter obtained by this means.

(Operation) The deviation between the target drive shaft torque and the actual drive shaft torque is fed back to the steady-state engine output control amount based on the target drive shaft torque, and the transmission delay until the intake air is reflected in the torque, and the torque is driven. Non-linear elements of the vehicle power generation and transmission process, such as transmission delay before transmission to the shaft, are reduced. In particular, the gain of the feedback changes sequentially according to the behavior of the vehicle, and the power generation and transmission process of the vehicle has a more linear characteristic.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an air cleaner;
And an air flow sensor 3. This air flow sensor 3 detects the amount of intake air sucked through the element 2.

An intake path 5 for introducing combustion air from the air cleaner 1 to the engine main body 4 is provided, and a throttle valve 6 is provided in a middle part of the intake path 5. In the intake path 5, reference numeral 5a denotes a surge tank.

The throttle valve 6 adjusts the amount of air passing through the intake passage 5, and can smoothly rotate from a fully closed position to a fully opened position. The rotation axis of the throttle valve 6 is DC
It is connected to the shaft of the motor 7.

Further, a throttle opening sensor 8 is attached to a rotation shaft of the throttle valve 6. The throttle opening sensor 8 is, for example, a potentiometer and outputs a signal of a voltage level corresponding to the opening of the throttle valve 6.

Further, a torque converter 9 is provided on the output side of the engine body 4.
The shaft 10 is connected to a turbine of the torque converter 9. In addition, shaft 10
Is connected to a drive shaft 12 via a transmission 11,
Wheels 13 are mounted on the drive shaft 12.

Note that an automatic transmission is configured by the torque converter 9, the shaft 10, and the transmission 11.

The intake air amount A detected by the air flow sensor 3 is sent to an engine control computer (hereinafter, referred to as ECI) 14, where the intake air amount A / Nr per revolution.
Is calculated for each predetermined crank angle, and the intake air amount A / Nr
Is injected into the cylinder of the engine body 4 in an amount determined according to the amount of fuel.

Further, the intake air amount A / Nr obtained by the ECI 14 is supplied to an air amount control unit 40 described later.

In addition, as for the unit of the intake air amount, the air amount A / N per rotation is used in the following description.

On the other hand, 20 is an accelerator pedal, and the accelerator pedal 20
Is detected by the accelerator pedal position sensor 21. Then, the detection output of the accelerator pedal position sensor 21 is supplied to the target drive shaft torque determination unit 22.

The target drive shaft torque determining unit 22 determines the accelerator pedal position Ap.
And a vehicle speed V detected by a vehicle speed sensor or the like (not shown) as a parameter to determine the target drive shaft torque Twt. For example, in the low speed range, the accelerator pedal position Ap is determined regardless of the vehicle speed V in consideration of the feeling of acceleration at the start. The values corresponding to each other are determined equally, and when the vehicle speed V is equal to or more than a predetermined value, a value that decreases as the vehicle speed V increases is determined in consideration of speed stability (speed maintenance). FIG. 2 shows the determination conditions.

The target drive shaft torque Twt determined by the target drive shaft torque determination unit 22 is supplied to the subtraction unit 23 and to the target air amount calculation unit 30.

The subtraction unit 23 subtracts the actual drive shaft torque Twm supplied from the actual drive shaft torque calculation unit 24 from the target drive shaft torque Twt to obtain a torque deviation ΔTw.

The actual drive shaft torque calculating unit 24 calculates an engine speed Ne detected by an engine speed sensor (not shown) and a torque capacity coefficient C of the torque converter 9 stored in advance.
The actual drive shaft torque Twm is calculated from the following equation using the torque ratio τ.

Twm = τ (e) C (e) Ne ² where e is the rotational speed ratio between the output shaft of the engine body 4 and the turbine of the torque converter 9, and this rotational speed ratio e
Is used as a parameter to determine the torque capacity coefficient C and the torque ratio τ. This relationship is shown in FIG.

It should be noted that the actual drive shaft torque Twm can also be obtained by measurement using a torque meter without using calculation.

The target air amount calculation unit 30 is a steady engine output torque calculation unit 31 that calculates a steady engine output torque Teo from the target drive shaft torque Twt, and is a steady engine output control amount based on the steady engine output torque Teo obtained by the calculation unit 31. A steady-state air amount calculation unit 32 for calculating a steady-state intake air amount A / No, a controller 33 for obtaining a feedback operation amount ΔA / N from the torque deviation ΔTw, and a correction amount for the operation amount ΔA / N obtained by the controller 33. The target intake air amount A / Nt, which is the target engine output control amount, is calculated based on the target drive shaft torque Twt and by feedback of the torque deviation ΔTw. Is what you want.

Here, the steady-state engine output torque calculating unit 31 considers the gear ratio ρ of the transmission 11 and the torque ratio τ of the torque converter 9 as shown in the following equation, and calculates the steady-state engine torque in the steady state corresponding to the target drive shaft torque Twt. Engine output torque T
eo is calculated and output as steady engine output torque.

Teo = Twt / (ρτ) The steady air amount calculation unit 32 maps the relationship between the intake air amount A / N and the engine output Te shown in FIG. 4 (correspondence table).
And obtains a steady intake air amount A / No corresponding to the steady engine output torque Teo based on the map. It is of course possible to store the relationship in FIG. 4 as a mathematical expression and calculate the steady intake air amount A / No using the mathematical expression.

The adjuster 33 is, for example, a PID adjuster, and uses an integral gain c ₀ , a proportional gain c ₁ , and a differential gain c ₂ that are sequentially set by a gain calculator 60 described later, and calculates the torque deviation ΔTw from the following equation. This is obtained by calculating the feedback operation amount ΔA / N.

ΔA / N = c ₀ ∫ (ΔTw) + c ₁ (ΔTw) + c ₂ d / dt (ΔTw) The controller 33 is not limited to the PID controller, but may be a P controller, a PI controller, a PD controller, Any such as a state feedback regulator may be used.

Thus, the target intake air amount A / Nt obtained by the target air amount calculation unit 30 is supplied to the air amount control unit 40.

The air amount control unit 40 uses the engine speed Ne as a parameter to determine the target intake air from the target air amount calculation unit 30 based on the relationship between the intake air amount A / N and the throttle opening θ as shown in FIG. It calculates a target throttle opening theta ₁ corresponding to the amount a / Nt, and supplies the opening degree setting signal voltage level corresponding to the target throttle opening theta ₁ to the motor drive control unit 25.

Further, the air amount control unit 40 feeds back the intake air amount A / Nr in order to correct a deviation of the intake air amount due to a throttle position error.

 FIG. 6 shows a specific example of the air amount control unit 40.

As shown in FIG. 6, the target intake air amount A / Nt is supplied to a target throttle opening calculating section 41 and a subtracting section 42.

The target throttle opening calculator 41 calculates the target intake air amount A / Nt
The target throttle opening θt is calculated based on the engine speed Ne and the engine speed Ne.

The subtraction unit 42 calculates a deviation between the target intake air amount A / Nt and the intake air amount A / Nr, and the deviation becomes a feedback operation amount Δθ in the PI controller 43. Then, the operation amount Δθ is added to the target throttle opening θt by an adder 44, the final target throttle opening theta ₁ is adapted to obtain.

The motor drive controller 25 controls the stepping motor 7 so that the output voltage level of the throttle opening sensor 8 matches the voltage level of the opening setting signal from the air amount controller 40.
Is to be driven.

On the other hand, reference numeral 50 denotes a model parameter calculation unit which stores a mathematical model that linearly represents a power generation and transmission process of the vehicle as a state deviated from its equilibrium state (= steady state),
The parameters (coefficients) of the mathematical model a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ ,
a ₃₃ is the behavior of the vehicle, the intake air amount A / Nr, the engine speed
It is obtained by sequentially performing back calculation from detection data such as Ne and vehicle speed V.

The parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , and a ₃₃ calculated by the model parameter calculator 50 are supplied to the gain calculator 60.

The gain calculation unit 60 includes the entire vehicle including the feedback control system mainly including the adjuster 33 as one system, and the characteristics from the intake to the torque transmission of the system are similar to the transmission characteristics of the reference response system. The feedback gain, that is, the PID gain is calculated using the parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , and a ₃₃ , and the PID gain is set to the controller 33.

A PID gain is calculated in advance from the parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , and a _33, and the calculated PID gain is stored in the gain calculation unit 60 as a map. A configuration may be adopted in which a PID gain is obtained by referring to a map by referring to the map.

Here, the mathematical model stored in the model parameter calculation unit 50 is shown in FIG.

This mathematical model is based on a predetermined amount passing through the throttle valve 6.
How the air of Ai (A / Nr) is converted into drive shaft torque and appears in the behavior of the vehicle is expressed linearly and as a deviation from the equilibrium state.

That is, Ar is the amount of air in the explosion process corresponding to the engine output, and is a variable indicating the behavior of the vehicle together with the engine speed Ne and the vehicle speed V.

That is, the air of the predetermined amount Ai passing through the throttle valve 6 becomes the air amount Ar via the intake delay element [1/1 + Ta S]. The amount of air Ar engine output Te next via the parameters a _21, the inertial element [1 / Ie of the engine output Te is engine
S], and becomes the engine speed Ne.

Engine speed Ne, as well as back to the input side of the engine inertia through the parameters a _22, parameters a _32, a gear ratio elements (1 / ρ), the vehicle speed V through a vehicle body inertial element [1 / It S]. This vehicle speed V is converted into a turbine rotational angular speed ωt by a gear ratio ρ.

Turbine rotation angular speed ωt, together with return to the input side of the engine inertia element via the parameters a _23, a parameter
returns to the input side of the gear ratio elements through a _33.

Ta is the intake time constant determined by the volume of the intake pipe and the volume of the engine cylinder. S is a transfer function. Ie is the moment of inertia of the engine. It is the body moment of inertia. ρ is the gear ratio of the transmission 11. Load is the road load. The parameter a ₂₁ is a conversion factor between the air quantity A / N and the engine output Te shown in Figure 4. Parameters a ₂₂ , a ₂₃ , a
₃₂ , a ₃₃ are the third values used to determine the target drive shaft torque Twt.
It corresponds to the torque converter characteristics shown in the figure.

Therefore, if the explosion process air amount Ar is estimated and assigned by calculation, and the engine speed Ne, the vehicle speed V, and the air amount Ai are assigned as measured data, the parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , a
₃₃ can be calculated back.

Hereinafter, a process until the above mathematical model is created will be described.

 First, transmission of the air amount will be described.

The change per unit time of the air mass in the air passage volume downstream of the throttle valve is the difference between the inflow from the throttle valve and the outflow to the cylinder.

m = Gin−Gex (1) Here, Gm is the air mass in the air passage volume downstream of the throttle valve. Gin is the amount of air passing through the throttle valve per unit time. Gex is the cylinder intake air amount per unit time.
These Gm, Gin, and Gex are shown in the intake system of FIG.

 Gex is proportional to Gm and engine speed Ne.

Here, V ₁ downstream of the air passage volume of the throttle valve. V ₂
Is the cylinder volume and η is the volumetric efficiency. To is a time constant per one engine revolution.

Substituting this equation into equation (1) gives Becomes

This indicates that the air amount has a first-order lag transfer characteristic.

Rewriting equation (3) using the relationship between Gex and Gm in equation (2), the relationship between the mass of air flowing through the throttle valve and the mass of cylinder intake air is Becomes

By dividing both sides of the equation (4) by the number of revolutions per unit time, the equation (5) relating to the air amount (A / N) is derived.

Here, Ao (t) is the amount of air taken into the cylinder. Ai
(T) is the amount of air passing through the throttle valve.

The amount of the air is changed to the torque at a point in time after a cycle process of intake, compression, and explosion has been performed after being taken into the cylinder. This is represented as wasted time in control. This wasted time is in charge of 1.5 revolutions when counted from the start of the intake process, and the following equation is obtained.

Here, (Lo / Ne) is a dead time.

Equation (7) expresses the relationship between the intake air amount Ao of the cylinder and the air amount Ar in the explosion process corresponding to the engine output.

On the other hand, the equilibrium state (Ne, ωt, A
o, Ar), it is assumed that the explosion process air amount Ar, the engine rotational angular velocity ωe, and the turbine rotational speed ωt change from the equilibrium state by a small amount ΔAr, ΔNe, Δωt in accordance with the change ΔAi in the input air amount. I do.

 In this case, the following relationship for the air amount is established.

As for the air amount, the time constant of the transfer characteristic from the air amount Ai passing through the throttle valve to the air amount Ar in the explosion process is represented by (ωe /
T _L ) was approximated by a first-order delay.

Here, by the process of being in the equilibrium state, Ar = Ai is established, and the following form is obtained.

Further, the following equation holds for the engine rotation angular velocity ωe.

I (e + Δe) = Te (ωe + Δωe, Ar + ΔAr) −T _P (ωe + Δωe, ωt + Δωt) (13) where Tp is an absorption torque of the torque converter.

Then, it is assumed that the engine output Te changes from the equilibrium state by ΔTe and the torque converter absorption torque Tp changes by ΔTp with respect to the change of ΔAr.

Then, the Te (ωe + Δωe, Ar + ΔAr) = Te (ωe, Ar) + ΔTe ...... (14) T P (ωe + Δωe, ωt + Δωt) = T P (ωe, ωt) + ΔT P ...... (15).

Since (ωe, ωt, Ar) is in an equilibrium state, the following equation is obtained.

e = 0 ...... (16) Te (ωe, Ar) = T P (ωe, ωt) ...... (17) equation of small change in the engine rotational angular velocity .omega.e is as follows.

IeΔe = ΔTe−ΔT _P (18) ΔTe, ΔTp are represented by the following linear equations for Δωe, Δωt, ΔAr.

Similar considerations apply to turbines.

 As a result, the following linear differential equation is obtained.

Δr = −TaΔAr + TaΔAi (21) Here, ∂Te / ∂Ar in the equation (22) is set to the parameter a ₂₁ The parameter A ₂₂ The parameters a ₂₃ (23) equation parameters a ₃₂ to ∂Tt / ∂ωe of A as a parameter a _33.

 Tt is the output torque of the torque converter.

Therefore, the system has the following state space expression format.

= Aω + Bu (24) y = Cω (25) ω = [ΔAr, Δωe, Δωt] ^t state vector A = [a ij] system matrix (21) (22) (22) (23) , Δωt coefficient B = [Ta, 0,0] ^t input coefficient vector C = output coefficient vector (eg, [0,0,1] for turbine speed) u = input, y = output This is an explanation of the process leading to the creation of a model.

Hereinafter, a transfer function serving as a reference for the gain calculation of the gain calculator 60 will be described.

In the above equations (24) and (25), the transfer function G (s) from the input u to the output y has the following form according to the definition of the transfer function.

G (s) = C [sI−A] ⁻¹ B (31) where s is a differential operator and I is a unit matrix.

From this equation, the transfer function Ge (s) from the intake air to the engine rotational angular velocity ωe, and the turbine rotation speed ωt from the intake air
Transfer function Gt (s) has the following form, respectively.

Here, H (s) = (s -a 11) (s-a 22) (s-a 33) - (s-a 11) a 23 a 32 b 1 = Ta, a 11 = -Ta ...... ( 34)

When the transfer function from the intake air to the drive shaft torque is obtained from the perturbation of the turbine torque, the following is obtained.

here, It is.

By substituting the above equations (32) and (33), the transfer function from the intake air to the turbine torque is as follows.

k is a coefficient depending on the load, , But it is almost zero and is ignored. Therefore,
This transfer function is Becomes In addition, T ₁ is the road load torque.

Set the denominator to (It b ₁ a ₂₁
a ₃₂ ) Becomes

here, It is.

That is, equation (41) is the transfer function of the vehicle to be controlled.

By the way, as described above, the gain calculation unit 60 captures the entire vehicle including the feedback control system mainly including the adjuster 33 as one system, and transmits the characteristic from the intake to the torque transmission of the system to the transmission of the reference response system. In this configuration, a PID gain is obtained using parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , and a ₃₃ so as to approximate characteristics.

The process up to obtaining the PID gain will be described below.

As shown in FIG. 8, the feedback control system and the vehicle to be controlled are regarded as one system, and the transfer characteristic of the reference response system is made to correspond to the target of the transfer characteristic from input / output to output of the system. As the reference response system, for example, a step response waveform shown in FIG. 9 is adopted.

The transfer function of the feedback control system And

The denominator of the transfer function of the reference response system, which is the target, is set as follows.

r (s) = 1 + r 0 + r 1 qs + r 2 q 2 s 2 + ... ...... (51) where, q is a factor for normalizing the response time.

1 + ro, r ₁ , r ₂ ,... Are parameters for determining the response waveform, and are determined according to the purpose.

The open loop transfer function of the system consisting of the feedback control system and the vehicle is Becomes This is shown in FIG.

The transfer characteristics of the closed loop are Becomes This is shown in FIG.

Assuming that the transfer function of the reference response system is equal to 1 / r (s), the following equation holds.

Expand the right-hand side into a denominator polynomial, and calculate its coefficients in order from low order
It is set equal to c ₀ , c ₁ , c ₂ .

For PID adjustment, c (s) is quadratic.

c (s) = c ₀ + c ₁ s + c ₂ s ² (59) Therefore, c ₃ = 0 is set and the above cubic equation (58) is solved. The minimum positive root at this time is q. This q is (55)
(56) c ₀ , c ₁ , c ₂ are obtained by using the equations (57).

c ₀ is an integral gain, c ₁ is a proportional gain, and c ₂ is a differential gain.

Next, the operation of the above configuration will be described with reference to FIG.

When the accelerator pedal 20 is depressed, the depression position Ap is detected by the accelerator pedal position sensor 21.

At this time, if the vehicle speed V is in a low speed range, the accelerator pedal position Ap is determined regardless of the vehicle speed V in consideration of the feeling of acceleration at the time of starting.
Is determined by the target drive shaft torque determining unit 22. If the vehicle speed V is equal to or higher than a predetermined value, the target drive shaft torque Twt that decreases as the vehicle speed V increases is determined by the target drive shaft torque determination unit 22 in consideration of speed stability (speed maintenance).

The determined target drive shaft torque Twt is supplied to the subtraction unit 23 and the target air amount calculation unit 30.

Simultaneously with the determination of the target drive shaft torque Twt, the actual drive shaft torque calculation unit 24 calculates the actual drive shaft torque Twm from the engine speed Ne, the torque capacity coefficient C of the torque converter 9 and the torque ratio τ. . Then, a deviation ΔTw between the target drive shaft torque Twt and the actual drive shaft torque Twm is obtained, and is supplied to the target air amount calculation unit 30 as a correction amount.

The target air amount calculation unit 30 transmits a steady engine output torque Teo corresponding to the target drive shaft torque Twt to the transmission 1
1 and the torque ratio τ of the torque converter 9.
The steady intake air amount A / No required to obtain o is obtained from the map. At the same time, the controller obtains a feedback operation amount ΔA / N based on the torque deviation ΔTw from the controller 33. Then, the operation amount ΔA
/ N is added to the steady intake air amount A / No, and the target intake air amount A / Nt
Ask for.

Thus, when the target intake air amount A / Nt is obtained, the throttle opening theta ₁ required to obtain the target intake air amount A / Nt is calculated at the air amount control unit 40. Then, an opening setting signal corresponding to the throttle opening θ ₁ is transmitted to the motor drive control unit.
25, and the throttle valve 6 is set to the target throttle opening θ.
The step motor 7 is driven so as to reach t.

Thus, for the steady intake air amount A / No based on the target drive shaft torque, the target drive shaft torque Twt and the actual drive shaft torque T
By feeding back the deviation ΔTw from wm, the air taken in through the throttle valve 6 is supplied to the intake passage 5, the intake air,
Power generation and transmission processes of the vehicle, such as transmission delay until the torque is reflected through the cycle process of compression and explosion, and transmission delay until the torque output from the engine body 4 is transmitted to the drive shaft 12 through the torque converter 9 The non-linear element possessed by decreases.

On the other hand, the intake air amount A / Nr and the engine speed Ne and the vehicle speed V indicating the behavior of the vehicle are input to the model parameter calculation unit 50 as actual measurement data, and the calculation unit 50 calculates the parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , a ₃₃ are required.

The model parameter calculating unit 50 estimates the explosion process air amount Ar from the input data, and assigns it to the mathematical model of FIG. 7 by changing it together with the input data, and the parameters a ₂₁ , a ₂₂ , a ₂₃ ,
a ₃₂ and a ₃₃ are back calculated.

In this case, as the behavior of the vehicle changes, the parameters to be obtained change sequentially.

Thus, the parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , and a ₃₃ are supplied to the gain calculator 60, where the PID gain is calculated.

In calculating the PID gain, the vehicle and the feedback control system are regarded as one system, and the calculation is performed such that the characteristics from the intake to the torque transmission of the system approximate the transmission characteristics of the reference response system. Then, the calculated PID gain is sequentially set in the controller 33.

That is, the manipulated variable ΔA / N obtained by the controller 33 includes an element that always linearizes the characteristics of the power generation and transmission process of the vehicle regardless of a change in the behavior of the vehicle.
In addition, it also includes an element that attempts to approximate all the transfer characteristics including the feedback control system to the transfer characteristics of the reference response system.

As described above, by sequentially setting the feedback gain while capturing the change in the behavior of the vehicle, the power generation and transmission process of the vehicle can be made more linear.

Therefore, good responsiveness from the intake to the transmission of the torque to the drive shaft 12 can be ensured, and the desired drive shaft torque can be quickly and accurately exhibited. Moreover, there is no need for a troublesome work of searching for the feedback gain by trial and error such as a driving experiment.

Furthermore, since all the transfer characteristics including the feedback control system are similar to the transfer characteristics of the reference response system, the responsiveness from intake to transmission of torque to the drive shaft 12 can be greatly improved.

With these effects, auto cruise control and traction control can be integrated as one system with high precision.

In addition, there is an advantage that the failure diagnosis of the vehicle can be performed online using the mathematical model stored in the model parameter calculation unit 50.

FIG. 13 shows the drive shaft torque Tol actually transmitted to the drive shaft 12 while the vehicle is running, and compares it with other measurement data.

That is, the engine speed Ne and the engine output Te change to reduce the nonlinear element of the power generation and transmission process,
The drive shaft torque Tol is maintained substantially constant at the target drive shaft torque Twt.

For reference, FIG. 14 shows measurement data of a vehicle in which the accelerator pedal and the throttle valve are mechanically connected.

In other words, if the depression position Ap of the accelerator pedal is kept constant, the engine speed Ne and the engine output Te are stabilized.
Tol decreases.

In the above embodiment, the PID controller is used as the feedback controller. However, as described above, the P controller and the PI controller are used.
Any of a regulator, a PD regulator, a state feedback regulator and the like may be used.

For example, when using a state feedback regulator,
The operation amount ΔA / N is obtained by the calculation of the following equation.

ΔA / N = k ₁ A / Nr = k ₂ Ne + k ₃ V k ₁ , k ₂ , k ₃ are feedback gain, intake air amount A / Nr,
The engine speed Ne and the vehicle speed V are actually measured data.

In this case, the gain calculation unit 60 uses the parameters a ₂₁ , a ₂₂ , a ₂₃ , a ₃₂ , and a ₃₃ calculated by the model parameter calculation unit 50, and furthermore, provides an optimal regulator. The feedback gains k ₁ , k ₂ , and k ₃ are calculated so that the torque fluctuation is minimized. Then, the calculated feedback gains k ₁ , k ₂ , and k ₃ are set for the controller 33.

Further, in the above embodiment, the throttle valve is driven by a DC motor. However, the throttle valve is not limited to the DC motor, and may be driven by a step motor. And the throttle valve is set to the target throttle opening. Not only motor drive but also hydraulic drive or pneumatic drive is possible.

Further, the gasoline engine in which the engine output control amount is the intake air amount has been described as an example, but the present invention is similarly applicable to a diesel engine in which the engine output control amount is the fuel injection amount. In this case, the delay of the engine output is only the process delay from the intake to the explosion, so that the form of the transfer function is the same, except that the time constant is reduced and the feedback gain can be increased. However, the control
This is done with fuel amount, not A / N.

In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

[Effects of the Invention] As described above, according to the present invention, a means for determining a target drive shaft torque, a means for obtaining an actual drive shaft torque transmitted to the drive shaft, an actual drive shaft torque obtained by this means, Means for obtaining a deviation from the target drive shaft torque, means for obtaining a steady engine output torque from the target drive shaft torque, means for obtaining a steady engine output control amount from the steady engine output torque obtained by the means, Means for obtaining a target engine output control amount by feeding back the deviation with respect to the steady engine output control amount; means for adjusting the engine output control amount according to the target engine output control amount obtained by the means; A mathematical model representing the process linearly and as a deviation from the equilibrium state, and parameters of the mathematical model Means and a means for setting the feedback gain by a parameter obtained by this means, so that good response from intake to torque transmission is ensured, and the desired drive shaft torque can be quickly obtained. Moreover, it is possible to provide an engine output control device that can exhibit its accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention and a configuration of a main part of a vehicle related thereto, FIG. 2 is a diagram showing conditions for determining a target drive shaft torque in the embodiment, and FIG. FIG. 4 is a diagram showing data used for calculating an actual drive shaft torque in the example, FIG. 4 is a diagram showing data used for calculating a steady engine output torque in the embodiment, and FIG. 5 is a diagram showing data used for calculating a throttle opening in the embodiment. FIG. 6 is a diagram showing a specific configuration of an air amount control unit in the embodiment, FIG. 7 is a diagram showing a mathematical model of a model parameter calculation unit in the embodiment, and FIG. FIG. 9 is a diagram showing an example of a reference response system which is a target of gain calculation in the embodiment, and FIG.
10 and 11 are diagrams each showing a gain calculation process in the embodiment, FIG. 12 is a flowchart for explaining the operation of the embodiment, and FIG. 13 is a diagram for explaining the effect of the embodiment. FIG. 14 is a diagram showing a conventional engine output control for reference. 4 engine body, 6 throttle valve, 9 torque converter, 12 drive shaft, 22 target drive shaft torque determination unit, 23 subtraction unit, 24 day drive shaft torque calculation unit , 30... A target air amount calculation unit, 33... A controller, 50... A model parameter calculation unit, 60.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Shimada 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Katsunori Ueda 5-33-8 Shiba, Minato-ku, Tokyo (56) References JP-A-63-74733 (JP, A) JP-A-63-75334 (JP, A) JP-A-63-45438 (JP, A)

Claims (1)

(57) [Claims] 1. A vehicle for transmitting an engine output based on an engine output control amount to a drive shaft, means for determining a target drive shaft torque, means for obtaining an actual drive shaft torque transmitted to the drive shaft, and the means for determining the actual drive shaft torque. Means for determining a deviation between an actual drive shaft torque and the target drive shaft torque; means for determining a steady engine output torque from the target drive shaft torque; and means for determining a steady engine output control amount from the steady engine output torque determined by the means Means for obtaining the target engine output control amount by feeding back the deviation with respect to the steady engine output control amount obtained by this means, and means for adjusting the engine output control amount according to the target engine output control amount obtained by this means And a mathematical model representing the power generation and transmission process of the vehicle as a linear and deviation from an equilibrium state. Means for determining by back calculation the parameters of the mathematical model from the behavior of the vehicle, the engine output control device being characterized in that and means for setting the gain of the feedback by parameters obtained in this way.