JP3951320B2 - Engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine control device for a vehicle, and more particularly to a device characterized by acceleration control.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an engine control device having a so-called linkless throttle in which a throttle valve is separated from an accelerator and can be opened and closed by driving a motor is known. In such an engine control device, the accelerator opening is detected, and the linkless throttle is motor-driven so that the throttle opening corresponding to the opening is obtained.
[0003]
Here, when the throttle opening is kept constant, the amount of intake air per revolution decreases as the engine speed increases, so the engine output decreases and the acceleration force gradually decreases. Generally known.
For this reason, in such a linkless throttle type engine control device, at the time of acceleration, the linkless throttle is first opened to a throttle opening corresponding to the depression amount of the accelerator pedal, and then the throttle opening is gradually increased at a predetermined speed. Accordingly, there is also known an apparatus that compensates for a decrease in engine output accompanying an increase in engine speed and maintains a constant acceleration (Japanese Patent Laid-Open No. Sho 61-210245).
[0004]
In the engine control device described in Japanese Patent Application Laid-Open No. 61-210245, the accelerator functions as an acceleration command means for commanding absolute acceleration, and the effect of reducing the burden on the driver's accelerator operation is expected. ing.
[0005]
[Problems to be solved by the invention]
However, even when driving a vehicle equipped with the engine control device described in Japanese Patent Application Laid-Open No. Sho 61-210245, at the time of acceleration, the driver does not depress the accelerator in consideration of the absolute value of the acceleration command. They are only depressing the accelerator in consideration of sensory acceleration. Then, an operation of holding the accelerator when a feeling of acceleration as intended is obtained, and returning the accelerator when it feels that acceleration is unnecessary is merely executed.
[0006]
However, in an actual vehicle, there is a delay in the response of the engine, and thus the vehicle may be further accelerated even after the accelerator return operation as described above is performed. This will be specifically described with reference to the drawings.
As shown in FIG. 14, it is assumed that the accelerator opening is increased from the initial value THM0 to THM1 and then returned to THM2 (<THM1). Further, it is assumed that the target engine output necessary to achieve the target acceleration corresponding to these THM1 and THM2 is TE1, TE2 (<TE1).
[0007]
In such a case, when the actual engine output has increased only as shown by the dotted line due to the response delay of the engine, and the actual engine output when the accelerator is returned is smaller than TE2, the accelerator is returned. After that, the vehicle will be further accelerated (period of the arrow shown in the figure).
[0008]
However, returning the accelerator means that the driver thinks that acceleration is no longer needed, or that he wants to weaken acceleration, so it will be strong if acceleration continues as shown in the figure. It will give you a sense of discomfort.
Therefore, an object of the present invention is to enable the acceleration to be reliably suppressed when the accelerator is returned.
[0009]
[Means for Solving the Problems]
The present invention provides a target acceleration command means for commanding a target acceleration in accordance with an accelerator depression amount, a target output calculation means for calculating a target engine output necessary for achieving the commanded target acceleration, and the calculation Based on the target engine output, target control amount calculation means for calculating a target control amount for a predetermined control target related to increase / decrease in engine output, and a control signal for the control target is increased / decreased until the target control amount is reached. An engine control device including control execution means is assumed.
[0010]
  AndClaim 1The invention provides an engine control apparatus as the premise described above, wherein an actual output detecting means for detecting an actual engine output, and the accelerator depression amountChanged backWhen, instead of the target output calculation means, based on the actual engine output detected by the actual output detection means, a target engine output for target control quantity calculation is given to the target control quantity calculation means.giveAccelerator return target setting means.
[0011]
  Also,Claim 2The invention provides an engine control apparatus as the premise described above, wherein an actual acceleration detecting means for detecting an actual acceleration and the accelerator depression amount areChanged backIn place of the target acceleration command means, an accelerator return that gives a target acceleration for target engine output calculation to the target output calculation means based on the actual acceleration detected by the actual acceleration detection means. And an hour target setting means.
[0012]
According to these engine control devices of the present invention, when the accelerator is returned, the subsequent engine control is executed based on the actual control state immediately before the accelerator is returned. Therefore, the same acceleration state as before does not continue even though the accelerator is returned.
[0013]
Also, in these engine control devices of the present invention, the accelerator return target setting means assumes that the actual engine output or actual acceleration is the target engine output or target acceleration immediately before the accelerator is returned. The target control amount calculation means or the target engine output calculation means is configured as a means for giving information, and the target acceleration command means is configured as a means for commanding an absolute target acceleration based on the accelerator depression amount. When the amount is decreased, it is preferable to switch to means for instructing a relative acceleration decrease amount based on the decrease amount.
[0014]
In this way, when the accelerator starts to be returned, the control target is updated by regarding the accelerator return operation as a relative acceleration decrease command. Therefore, if the accelerator is returned slightly, it can be processed as a hold command for the actual engine output so as to give the current actual acceleration, and if it is returned to a larger value, an acceleration decrease command for the actual acceleration can be processed. Can be processed as
[0015]
In order to achieve the object of the present invention, the state immediately before the accelerator may be held only when the accelerator is returned. However, since the intention of the driver who has returned the accelerator is not sufficiently reflected whether the acceleration is held or the acceleration is lowered, it is better to adopt the configuration as described above in order to be able to exert a step forward effect. is there.
[0016]
In the apparatus configured as described above, when the accelerator is depressed again, the accelerator return-time target setting means is released from its function, and the target acceleration command means determines the absolute target acceleration according to the accelerator depression amount. It is desirable to configure so as to return to the commanding means.
[0017]
The reason for releasing the above-described function of the accelerator return target setting means when the accelerator is depressed again is that it is difficult to re-accelerate. In re-acceleration, the target acceleration command means is returned to the means for instructing the absolute target acceleration again so that the acceleration force at the time of re-depression is not lowered.
[0018]
When the accelerator return is greater than or equal to a predetermined value, for example, when the accelerator is returned to a predetermined reference position, or when the accelerator is returned more than a predetermined value, the function of the accelerator return target setting means does not work from the beginning. It is good to do so. This is because, for example, if the absolute value of the accelerator depression amount is in a state of commanding an acceleration lower than the actual acceleration before the accelerator is returned, it is necessary to intentionally execute the control for suppressing the actual acceleration as described above. Because there is no.
[0019]
On the other hand, when the function of the accelerator return target setting means is released by depressing the accelerator, the output increase speed that suppresses the output increase speed until the engine output reaches the target engine output calculated by the target output calculation means. It is desirable to provide suppression means.
[0020]
This is because the target value is changed in a step shape by stepping on again, but if acceleration control is made to follow as it is, sudden acceleration may suddenly occur. Therefore, at the time of stepping on again, the output increase speed suppression means gradually increases the output to the target value so as not to generate a sense of incongruity due to a sudden acceleration that newly occurs due to the measures taken when returning the accelerator. Adopting the above-described configuration is proposed.
[0021]
In the engine control apparatus of the present invention, the control execution means outputs the predetermined control signal on the output increasing side so as to maintain the target engine output while a positive acceleration command is continued as the target acceleration. It may be configured as a means for compensating for a decrease in engine output accompanying an increase in engine speed during acceleration.
[0022]
With this configuration, even if the accelerator operation amount does not increase, the engine control conditions (for example, the throttle opening, the fuel injection amount, etc.) are adjusted to the output increasing side, and the engine output decreases as the engine speed increases. Minutes can be compensated. Therefore, once the target acceleration is reached, this can be maintained, and the burden on the driver's acceleration operation can be reduced.
[0023]
In this case, the running resistance detecting means for detecting the running resistance applied to the vehicle, and the running resistance compensating means for increasing the engine output so as to offset the increase in running resistance due to acceleration based on the detected running resistance. It is even better if it is provided with. The reason is as follows.
[0024]
First, considering the actual vehicle running state, the vehicle is subjected to running resistance such as rolling resistance, air resistance, gradient resistance, and acceleration resistance. Among these, for example, the air resistance increases as the vehicle speed increases. Therefore, when driving on an expressway where the influence of air resistance is large, it is difficult to achieve acceleration at a constant acceleration unless this driving resistance is taken into account. A delicate accelerator operation that relies on feeling is required. However, in such a high speed range, the accelerator has already been stepped down to a deep position, so it is not easy to operate the accelerator to maintain a constant acceleration, and in the end, the driver may not get the acceleration feeling intended. is there.
[0025]
On the other hand, if a configuration is added so that the running resistance can be detected and the control reflecting this can be executed as described above, the engine output is increased so as to offset the increase in air resistance and acceleration resistance during acceleration. The vehicle can be accelerated while keeping the actual acceleration constant. Such constant acceleration of the actual acceleration can be achieved without increasing the accelerator operation amount, so that the driver does not need to delicately operate the accelerator.
[0026]
In this way, by making it possible to compensate for running resistance, the driver can enjoy a comfortable acceleration feeling without feeling the breath of the engine, and the accelerator operation for that purpose is further simplified. can get.
In carrying out the present invention, the gasoline engine vehicle includes a linkless throttle that is not mechanically linked to the accelerator but driven by an actuator, and the control signal is a throttle opening command for the linkless throttle. It is better to be. This is because the increase / decrease in engine output can be adjusted by the fuel injection amount, etc., but if adjusted by the intake air amount, acceleration at the intended acceleration can be realized without adversely affecting the air-fuel ratio. It is.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
This embodiment relates to a front engine / rear drive (FR) type vehicle using an internal combustion engine 2 as a power source, as shown in FIG.
[0029]
As shown in the figure, a surge tank 4 a that suppresses pulsation of intake air is formed in the intake passage 4 of the internal combustion engine 2, and a throttle valve 12 that is opened and closed by a throttle drive motor 10 is provided upstream thereof. The throttle valve 12 is not directly opened and closed by the accelerator 6, but is a so-called linkless throttle.
[0030]
The accelerator 6 and the throttle valve 12 are provided with an accelerator opening sensor 14 and a throttle opening sensor 16 for detecting the respective opening, and detection signals from these sensors are input to the throttle control circuit 20. .
A fuel injection valve 24 that supplies fuel to the internal combustion engine 2 operates based on a fuel injection command from a known internal combustion engine control circuit 26. The fuel injection command is determined in conformity with the operating state of the internal combustion engine 2, and information from various sensors including the intake pressure sensor 28 that detects the pressure of the surge tank 4 a is received from the internal combustion engine control circuit 26. It is created by processing based on the fuel injection command program.
[0031]
In addition to the accelerator opening sensor 14 and the throttle opening sensor 16 described above, the throttle control circuit 20 includes an engine speed sensor 30, driven wheel speed sensors 32FL and 32FR, a driving wheel speed sensor 40, a gear ratio sensor 42, and an acceleration. A detection signal from the sensor 44 is also input. The throttle control circuit 20 drives the throttle drive motor 10 based on these input signals, and executes a process for controlling the opening degree of the throttle valve 12.
[0032]
Here, the engine rotation speed sensor 30 detects the rotation speed of the crankshaft 2 a of the internal combustion engine 2, and is also used to create a fuel injection command by the internal combustion engine control circuit 26.
The driven wheel speed sensors 32FL and 32FR are sensors for detecting the rotational speeds of the left and right driven wheels (front wheels) 22FL and 22FR, respectively. When performing traction control or the like, the detection signal is used to estimate the vehicle body speed of the vehicle. Used for
[0033]
The drive wheel speed sensor 40 is a sensor for detecting the average rotational speed (drive wheel speed) of the left and right drive wheels 22RL and 22RR, and the rotation of the crankshaft 2a is determined by the left and right drive wheels 22RL via the propeller shaft 34 and the differential gear 36. , 22RR is provided on the output shaft of the transmission 38.
[0034]
The gear ratio sensor 42 is for detecting the gear ratio of the transmission 38 and is provided in the transmission 38 in the same manner as the drive wheel speed sensor 40.
The acceleration sensor 44 is a known semiconductor G sensor. The acceleration sensor 44 detects a combination of the gradient and the vehicle G. Accordingly, the gradient can be detected by calculating the vehicle body acceleration and subtracting the vehicle body acceleration from the detection value of the acceleration sensor 44.
[0035]
Next, the throttle control circuit 20 that is a characteristic part of the present embodiment will be described in more detail.
The throttle control circuit 20 is composed of a microcomputer having a CPU, ROM, RAM, etc., and the ROM includes an “acceleration” representing the relationship between the accelerator opening THM and the acceleration command value αtgt, as shown in FIG. "Target map" is stored. The figure is an image, and the actual map is obtained by converting the relation of this figure into numerical data. As can be seen from this map, when the accelerator opening THM is 0 (that is, when the accelerator 6 is not depressed at all), the maximum deceleration state is commanded, and thereafter, the deceleration command decreases as THM increases. ing. Then, with THM = THM0 as a boundary, deceleration (αtgt <0) is achieved in the region of THM <THM0, constant speed running (αtgt = 0) is achieved in THM = THM0, and acceleration is performed in the region of THM> THM0 (αtgt> It can be seen that 0) is in the commanded state.
[0036]
Further, in the ROM of the throttle control circuit 20, as shown in FIG. 2 (b), the relationship between the target acceleration αtgt and the target increase ΔTEtgt (THM) of the engine output necessary to achieve the target acceleration αtgt. An “output increase target map” is also stored. From these relationships, the target increase ΔTEtgt (THM) of the engine output corresponding to the accelerator opening degree THM can be obtained. 2 (a) and (b) may be combined into a map that directly gives the target increase amount ΔTEtgt (THM) of the engine output from the accelerator opening degree THM.
[0037]
Further, the ROM of the throttle control circuit 20 also stores an “engine output characteristic map” indicating the relationship between the throttle opening TH, the engine speed NE, and the engine output TE as shown in FIG.
Next, the processing contents of the throttle opening degree control performed by the throttle control circuit 20 will be described based on the flowchart of FIG. This process is performed as an interrupt routine every predetermined time.
[0038]
First, the detection signal THM of the accelerator opening sensor 14 is input (S10), and it is determined whether THM> THM0 is satisfied (S20). That is, it is determined whether or not the driver intends to accelerate.
If it is determined that THM> THM0, it is first determined whether or not the current accelerator opening THMn is smaller than the previous accelerator opening THMn-1 (S22). If THMn <THMn-1, the accelerator return target setting process is executed (S300). The contents of this process will be described later.
[0039]
If S22 = NO, it is determined whether or not “1” is set in the accelerator return flag FA (S24). The accelerator return flag FA is set to “1” in an accelerator return target setting process described later, but is initially reset to “0”. Therefore, S24 = NO at the start of the first acceleration, and the process proceeds to S30. In S30, it is determined whether THM> THM0 also at the previous processing timing. When S30 = NO, that is, immediately after the transition from THM ≦ THM0 to THM> THM0, the throttle opening TH and the engine speed NE at that time are input (S40), and TH, The current engine output TE is obtained by referring to the engine output characteristic map at NE, and the value is stored as the base output TE0 (S50).
[0040]
Then, the acceleration target value αtgt is obtained by referring to the acceleration target map with the accelerator opening THM, and the target increase amount ΔTEtgt (THM) of the engine output is calculated with reference to the output increase target map with this αtgt. (S60).
Subsequently, the wheel speed signals VFL and VFR detected by the driven wheel speed sensors 32FL and 32FR, the vehicle body G signal Gtotal detected by the acceleration sensor 44, the drive signal SAT of the speed change control solenoid detected by the speed ratio sensor 42, and the engine speed sensor The engine rotational speed NE detected by 30 is input (S70).
[0041]
Then, the vertical acceleration component Gslope due to the road surface gradient is calculated from the longitudinal acceleration component of the vehicle body and the vehicle body G signal Gtotal (S80). Specifically, first, the current vehicle speed V = (VFL + VFR) / 2 is calculated, and the actual acceleration α = (V−Vold) / t (where t is the interrupt time interval) from the difference from the previously calculated vehicle speed Vold. ). Next, the acceleration component Gslope due to the road surface gradient is calculated by subtracting the actual acceleration α from the vehicle body G signal Gtotal.
[0042]
Next, the running resistance R is calculated based on the following formula (S90).
[0043]
[Expression 1]
R = Rr + R1 + Ri + Ra
Rr = μr (V) · W
R1 = μ1 ・ A ・ V²
Ri = W · sinθ
Ra = (1 + φ) · W · α / g
Here, Rr: rolling resistance [kN], R1: air resistance [kN], Ri: gradient resistance [kN], Ra: acceleration resistance [kN], μr (V): rolling resistance coefficient (change in contact force due to vehicle speed V) W: the total weight of the vehicle body [kN], μ1: air resistance coefficient [kN · h²/ M²・ Km² ], A: Front projection area [m² ], V: Vehicle speed (km / h), θ: Inclination angle [deg], φ: Apparent weight increase when considering the rotating part, α: Acceleration [m / s² ], G: acceleration of gravity [m / s² ]. Note that φ can be expressed as φ = Wr / W, where Wr [kN] is the rotation partial inertia weight. This Wr can be expressed by the following formula.
[0044]
[Expression 2]
Wr = g [IW + {IF + (IT + IE) .ir²} IF²] / RD²
Where IW: moment of inertia of the wheel and the same rotating part (tire, wheel, brake disc, brake drum, accelerator shaft) [kgm² ], IF: moment of inertia of the same rotating part as the final reduction gear input shaft (final reduction gear, propeller shaft, transmission main shaft, other driven gear) [kgm² ], IT: Inertia moment [kgm of the same rotating part (transmission main drive shaft, other drive side gear) as the transmission input shaft]² ], IE: moment of inertia of the same rotating part (crankshaft, piston, flywheel, clutch, etc.) as the engine output shaft [kgm² ], Ir: Transmission gear ratio, iF: Final reduction ratio, rD: Tire effective diameter of drive wheels [m].
[0045]
Of the above formulas 1 and 2, W, μ1, A, g, IW, IF, IT, IE, IF and rD are fixed values, and numerical values are stored in advance in the ROM. As for μr (V), information as a map for the vehicle speed V is stored in advance in the ROM. V and α are calculated in S80 as described above. Further, θ can be obtained from a map using Gslope as a parameter, and ir can also be specified by a map using the gear ratio signal γ as a parameter.
[0046]
If the running resistance R can be calculated in this way, then, the target increase amount ΔTEreg of the engine output necessary for offsetting the running resistance R is calculated by Equation 3 (S100).
[0047]
[Equation 3]
△ TEreg = R / (ir ・ iF)
Then, the actual target increase amount ΔTEtgt is calculated from ΔTEtgt (THM) and ΔTEreg according to the following formula (S110).
[0048]
[Expression 4]
△ TEtgt = △ TEtgt (THM) + △ TEreg
Then, the target engine output TEtgt is calculated by adding the actual target increase amount ΔTEtgt to the base output TE0 stored in S50 (S120).
[0049]
[Equation 5]
TEtgt = TE0 + △ TEtgt
When the target engine output TEtgt can be calculated in this way, the target value THtgt of the throttle opening is calculated by referring to the engine output characteristic map using this and the current engine speed NE (S130). Then, the throttle drive motor 10 is driven and controlled so as to be the target value THtgt of the throttle opening (S140). If it is determined NO in S20, the routine is exited because the vehicle is in a constant speed running or deceleration command state.
[0050]
Next, the accelerator return target setting process will be described. This routine is configured as shown in FIG. 5. First, it is determined whether or not the accelerator return flag FA is set to “1” (S310). When this routine is executed for the first time, since FA = 0, the routine proceeds directly to S320, and the previous accelerator opening THMn-1 is stored as the accelerator opening THMst. Then, the driven wheel speeds VFL and VFR and the driving wheel speed VR are input (S330). First, the vehicle speed V is calculated based on the driven wheel speeds VFL and VFR, and the driving wheel rotational speed is calculated based on the driving wheel speed VR. ω is calculated (S340). Subsequently, the time differential value dV / dt of the vehicle speed V is calculated, and the time differential value dω / dt of the drive wheel rotational speed ω is calculated (S350), and the actual output TEreal of the current engine is calculated according to the following equation. (S360).
[0051]
[Formula 6]
TEreal = TEwhl / (t ・ i)
TEwhl = I · dω / dt + μ · Wr · R
μ · Wr = W · dV / dt
Here, TEwhl is the wheel drive torque, t is the torque ratio (torque amplification by the torque converter), i is the total reduction ratio (gear ratio x final reduction ratio), I is the inertia moment of the vehicle (including the drive shaft), and μ is Road surface friction coefficient, Wr is a rear load, R is a tire radius, and W is a vehicle weight.
[0052]
If the actual output TEreal of the engine can be calculated in this way, the accelerator return flag FA is set to 1 (S370). Then, the return coefficient K is calculated and stored based on the following equation (S380).
[0053]
[Expression 7]
K = (THMn-THM0) / (THMst-THM0)
Then, based on the following formula, the target increase amount ΔTEtgt (THM) of the engine output corresponding to the accelerator opening is calculated, and the routine proceeds to S70 (S390).
[0054]
[Equation 8]
△ TEtgt (THM) = K ・ (TEreal-TE0)
When this routine is executed after FA = 1, the processing of S320 to S370 is passed. Accordingly, the actual output TEreal immediately before the accelerator starts to be returned and the accelerator opening THMst are fixed until the routine is not executed thereafter, and only the return coefficient K and the target increase amount ΔTEtgt (THM) are updated. It will continue.
[0055]
Next, a case where the accelerator is depressed again and then depressed again will be described. In this case, as shown in the main routine of FIG. 4, S24 becomes YES, and then it is determined whether THMn = THMn-1 or not (S26). If S26 = YES, the process proceeds to S300 and the accelerator return target setting process is executed. If S26 = NO, the accelerator return target setting process is executed (S500).
[0056]
In this accelerator return process, as shown in FIG. 6, it is first determined whether or not this process has been executed last time (S510). When this processing is executed for the first time, S510 = NO, so the current target increase amount ΔTEtgt (THM) is stored as the return start value ΔTEtgt (THM) st (S520). Subsequently, as in S60, the acceleration target map αtgt corresponding to the accelerator opening THMn is obtained by referring to the acceleration target map at the current accelerator opening THMn, and the output increase target map is referred to by this αtgt. A target increase amount ΔTEtgt (THM) n of the engine output corresponding to the current accelerator opening is calculated (S530). The return start value ΔTEtgt (THM) st is updated by adding a predetermined minute output increment A1 (S540), and whether ΔTEtgt (THM) st ≧ ΔTEtgt (THM) n is satisfied. Is determined (S550).
[0057]
While ΔTEtgt (THM) st <ΔTEtgt (THM) n, ΔTEtgt (THM) st is adopted as ΔTEtgt (THM), and the process proceeds to S70 (S560). On the other hand, if ΔTEtgt (THM) st ≧ ΔTEtgt (THM) n, the return flag FA is reset to “0” (S570), and ΔTEtgt (THM) n is set as ΔTEtgt (THM). Adopt and move to S70 (S580). If S510 = YES, S520 is passed.
[0058]
Thus, after resetting to FA = 0 in S570, S24 = NO, and the same processing as in the case of simple acceleration is repeated. If S20 is NO, the flag is reset immediately to FA = 0 and the flag is reset (S26).
Next, the operation and effect of the above control processing will be described with reference to the timing charts of FIGS. First, the case where the vehicle is simply accelerated and the accelerator is not returned will be described with reference to FIG. In this example, it is assumed that the vehicle is traveling on a flat road without a gradient.
[0059]
Now, it is assumed that constant speed traveling is being performed with the accelerator opening degree THM = THM0 held until time t1. Until time t1, since S20 = NO, the throttle drive motor 10 continues to be controlled in the opening maintaining state, and the throttle opening TH is constant at a lower opening.
[0060]
Next, it is assumed that the accelerator 6 is depressed at time t1 and the opening degree increases to THM = THM1 by time t2. As a result, S20 = YES, and the processing from S30 is executed. Then, immediately after time t1, S30 = YES, S40 and S50 are executed, and the engine output during constant speed traveling is stored as the base output TE0. Even in the case where the update is performed in S55, since the substantial update of TE0 is not performed with the standard weight, TE0 stored in S50 remains as it is.
[0061]
Thereafter, the processing of S60 to S140 is executed, and until time t2, the throttle opening TH is increased almost linearly with the increase of the accelerator opening THM, and the vehicle speed is increased. Between times t1 and t2, a desired acceleration cannot be obtained immediately due to a response delay or the like. Therefore, the running resistance R is almost the same as that before time t1, and the engine speed NE itself is also delayed. The throttle opening TH is increased almost linearly. The change state of the throttle opening TH between the times t1 and t2 is the same as that according to the technique before the present invention.
[0062]
Thus, when the time t2 is reached and the accelerator opening TH is held at TH1, the engine output increases and acceleration starts. Along with this, a change occurs in the running resistance R. First, the air resistance R1 increases linearly as the vehicle speed increases. At the same time, the acceleration resistance Ra increases. Although the rolling resistance Rr slightly increases, it is ignored here. Further, as described at the beginning, since running on a flat road is taken as an example, the gradient resistance R1 is zero.
[0063]
As the running resistance R increases, the throttle opening TH after the time t2 is in a control state in which the throttle opening TH rises in a downward convex arc. Thus, according to the present embodiment, the running resistance R can be canceled and the vehicle acceleration can be kept constant.
In the control prior to the technology described in Japanese Patent Application Laid-Open No. 61-210245, the throttle opening is kept constant after the accelerator is held as shown by the dashed line in the figure, so the vehicle speed increases slowly and the driver's The intended acceleration cannot be obtained. Further, in the control by the technique described in Japanese Patent Application Laid-Open No. Sho 61-210245, the throttle opening TH is increased at a constant rate after time t2, as shown by the two-dot chain line in the figure, but an increase in running resistance is taken into consideration. As a result, the acceleration gradually decreases. For this reason, if the driver wants to continue accelerating the vehicle at the initial acceleration, the accelerator must be depressed further.
[0064]
On the other hand, according to the present embodiment, since the throttle opening is increased in consideration of running resistance, the acceleration intended by the driver can be obtained from the beginning to the end of acceleration. Thus, according to the present embodiment, the driver does not have to perform the troublesome operation of finely adjusting the amount of depression after depressing the accelerator 6 in order to obtain the intended acceleration. A more advantageous effect is achieved compared to the prior art.
[0065]
Next, assuming the state where the accelerator is temporarily returned at an early timing after acceleration and accelerated again, the operation and effect in that case will be described with reference to FIG. FIG. 7 described above describes the macro-like action / effect seen statically without considering the engine response delay, but this time, the action / effect taking the engine response delay into account will be described.
[0066]
It is assumed that the accelerator is depressed at time t11 and the accelerator opening increases from THM0 to THM1 by time t12. Then, in response to this, the throttle opening increases. However, the actual engine output TEreal is lower than the target engine output TEtgt1 as indicated by the dotted line due to a response delay. As a result, the vehicle speed is in a state of increasing only more slowly than the increase in the vehicle speed at the target acceleration indicated by the two-dot chain line from time t12.
[0067]
In such a transient state, it is assumed that the driver returns the accelerator to the opening degree THM2 between THM0 and THM1 (time t13 to t14). The target engine output TEtgt2 corresponding to the intermediate opening THM2 is larger than the actual engine output TEreal. Therefore, if the accelerator return target setting process described above is not performed, the engine output continues to increase and accelerates further as shown by the two-dot chain line branched from time t13 of the engine output curve and vehicle speed curve. End up. Although the driver returns the accelerator in an attempt to reduce the acceleration, the engine output delay increases as a result of the engine response delay. As a result, the acceleration increases rather, so the driver feels uncomfortable.
[0068]
On the other hand, according to the present embodiment, the target engine output is given so that the actual output TEreal at time t13 is equal to the target engine output at that time as a result of executing the accelerator return target setting process. It is done. Then, since the amount of decrease in the accelerator opening due to the subsequent return of the accelerator acts as a relative output decrease command, the throttle opening is decreased so that the actual output TEreal is gradually decreased according to the return amount of the accelerator. (Time t13 to t14). Therefore, the driver's accelerator operation and acceleration feel correspond to each other, and a comfortable driving can be promised without giving the above-mentioned uncomfortable feeling.
Next, assuming that the accelerator is depressed again to the original opening THM1 at time t15, the accelerator return target setting process is executed this time. As a result, the target engine output does not increase to TEtgt1 at a stretch, but gradually increases to TEtgt1, so that the vehicle speed changes smoothly and does not give an unpleasant acceleration shock (from time t16). For comparison, the state of the change in vehicle speed when the target engine output is increased at once is shown together with a line branched by a two-dot chain line from time t16.
[0069]
Next, a second embodiment will be described. In this embodiment, as shown in FIG. 9, when the accelerator opening THM changes in the return direction, the following accelerator return target setting process is executed as in the first embodiment (S22). → S700). In addition, the same step number is displayed on the step of the same processing content as 1st Embodiment, and description is abbreviate | omitted.
[0070]
This accelerator return target setting process is configured as shown in FIG. 10, and it is determined whether or not the accelerator return flag FA is set to “1” as in the first embodiment (S710). When FA = 0, the previous target acceleration αtgtn−1 is returned and stored as the initial target acceleration αst (S720). Then, the driven wheel speeds VFL and VFR are input (S730), and the vehicle speed V is calculated (S740). Subsequently, the actual acceleration αreal is calculated as the time differential value dV / dt of the vehicle speed V (S750). Then, αreal / αst is stored as a return coefficient Kα (S760), and the flag FA is set to 1 (S770). Then, the accelerator opening THM is calculated based on the following equation, and the process proceeds to S60 (S780).
[0071]
[Equation 9]
THM ← Kα ・ (THM−THM0) + THM0
Next, a case where the accelerator is depressed again and then depressed again will be described. In this case, as shown in the main routine of FIG. 9, the process proceeds to S800 to execute accelerator return target setting processing.
[0072]
In this accelerator return target setting process, as shown in FIG. 11, it is first determined whether or not this process has been executed last time (S810). When this process is executed for the first time, S810 = NO, so the accelerator opening THM calculated in S780 at the present time is stored as the return start value THMst (S820). Subsequently, after updating THMst by adding a predetermined minute increment A2 (S830), it is determined whether THMst is equal to or greater than the current actual accelerator opening THMn (S840).
[0073]
While THMst <THMn, THMst is adopted as THM used in the calculation of S60 (S850). When THMst ≧ THMn, the return flag FA is reset to “0” (S860), and THMn is used as THM. The method is adopted to shift to S60 (S870). If S810 = YES, S820 is passed.
[0074]
According to the second embodiment, the same effect as that of the first embodiment can be obtained.
Next, a third embodiment will be described.
The third embodiment is similar to the first and second embodiments in terms of hardware configuration, and uses a system including an air flow meter instead of the intake pressure sensor 28. However, the present invention relates to a vehicle equipped with a simple engine control system that does not carry out an output addition in consideration of the running resistance as described above. In the ROM of the throttle control circuit 20 of this system, as shown in FIG. 12, the relationship between the accelerator opening THM and the basic throttle opening THbase is stored as a “basic throttle opening map”. Further, an “engine output characteristic map” similar to that in the first embodiment is also stored.
[0075]
Next, the throttle opening degree calculation process executed by the throttle control circuit 20 will be described based on the flowchart of FIG. This process is performed as an interrupt routine every predetermined time.
First, the accelerator opening correction coefficient KA for the return operation is set to “1” (S910). Then, the accelerator opening THM, the engine speed NE, and the intake air amount Q are input (S920). Then, THM is corrected to KA / THM, the engine output characteristic map is referred to together with NE, and the basic engine output TE is calculated in consideration of the intake air amount Q (S930, S940). Since KA is 1 at the beginning, the actual value of the accelerator opening THM is used for the calculation of S940.
[0076]
Further, the basic throttle opening TH is calculated by referring to the basic throttle opening map in THM (S950). Next, the current actual engine output TEreal is calculated by the same method as that executed in the accelerator return target setting process of the first embodiment (S960).
[0077]
Then, it is determined whether or not the accelerator return flag FA is set to “1” (S970). The accelerator return flag FA is initially reset to “0”. And when the accelerator opening is decreased, it is set to “1” (S980, S990).
[0078]
When the accelerator is started to return, the engine output characteristic map is referred to with the actual engine output TEreal at that time and the current engine speed NE, and TH that satisfies TEreal with respect to NE is set as the pseudo throttle opening TH '. (S1000). Next, the pseudo throttle opening THM 'corresponding to the pseudo throttle opening TH' is calculated by referring to the basic throttle opening map (S1010). Then, a correction coefficient KA is calculated by dividing the pseudo accelerator opening THM 'by the accelerator opening THMn-1 before the start of accelerator return, and this value is stored (S1020). As a result, in the subsequent processing of S950, the basic throttle opening TH is calculated on the assumption that the pseudo accelerator opening THM ′ = KA · THM, which is smaller than the actual accelerator opening THM, is commanded. Become.
[0079]
On the other hand, if FA = 1, it is determined whether or not the accelerator opening has changed again in the increasing direction (S1030). If the accelerator is depressed again, the correction coefficient KA is updated while adding the small increment B (S1040). When KA = 1, no further updating is performed and FA = 0 is reset. (S1050, S1060).
[0080]
With the above processing, even in the third embodiment, when the accelerator is once depressed and then returned, further acceleration due to engine response delay is not performed, and the accelerator is depressed again. In this case, the same effects as those of the first and second embodiments can be achieved, in which a comfortable acceleration performance can be exhibited without causing a large acceleration shock.
[0081]
The embodiments of the present invention have been described above. However, the present invention is not limited thereto, and it is needless to say that the present invention can be implemented in various forms without departing from the scope of the invention.
For example, even in a system in which processing for adding running resistance is removed from the first and second embodiments, it goes without saying that the present invention can be implemented as it is as a technique for eliminating the uncomfortable feeling of acceleration when the accelerator is returned. Nor.
[0082]
Further, in the embodiment, the system in which the throttle opening of the linkless throttle is controlled has been described. However, in the case of a diesel engine, the present invention is applied as a problem of control of the accelerator opening and the fuel injection amount. Can do.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a system used in an embodiment.
FIG. 2 is an explanatory diagram of an acceleration target map and an output increase target map used in the embodiment.
FIG. 3 is an explanatory diagram of an engine output characteristic map used in the embodiment.
FIG. 4 is a control flowchart according to the embodiment.
FIG. 5 is a control flowchart in the embodiment.
FIG. 6 is a control flowchart according to the embodiment.
FIG. 7 is a time chart of a control state in the embodiment.
FIG. 8 is a time chart of a control state in the embodiment.
FIG. 9 is a control flowchart according to the embodiment.
FIG. 10 is a control flowchart in the embodiment.
FIG. 11 is a control flowchart according to the embodiment.
FIG. 12 is an explanatory diagram of a basic throttle opening map used in the embodiment.
FIG. 13 is a control flowchart in the embodiment.
FIG. 14 is a time chart showing a conventional problem.
[Explanation of symbols]
2 ... internal combustion engine, 6 ... accelerator, 10 ... throttle drive motor, 12 ... throttle valve, 14 ... accelerator opening sensor, 16 ... throttle opening sensor, 20 ... Throttle control circuit, 24 ... fuel injection valve, 26 ... internal combustion engine control circuit, 28 ... intake pressure sensor, 30 ... engine speed sensor, 32FR, 32FL ... driven wheel speed sensor, 38 ... Transmission, 40 ... Drive wheel speed sensor, 42 ... Gear ratio sensor, 44 ... Acceleration sensor.

Claims (8)

Target acceleration command means for commanding the target acceleration according to the accelerator depression amount;
Target output calculation means for calculating a target engine output necessary to achieve the commanded target acceleration;
A target control amount calculating means for calculating a target control amount for a predetermined control object related to increase / decrease in engine output based on the calculated target engine output;
In an engine control device comprising control execution means for increasing or decreasing a control signal for the control object until a target control amount is reached,
Actual output detection means for detecting the actual engine output;
When the accelerator depression amount changes in the return direction, instead of the target output calculation means, the target control amount calculation means is set to a target based on the actual engine output detected by the actual output detection means. An engine control device comprising: an accelerator return target setting means for providing a target engine output for calculating a control amount. Target acceleration command means for commanding the target acceleration according to the accelerator depression amount;
Target output calculation means for calculating a target engine output necessary to achieve the commanded target acceleration;
A target control amount calculating means for calculating a target control amount for a predetermined control object related to increase / decrease in engine output based on the calculated target engine output;
In an engine control device comprising control execution means for increasing or decreasing a control signal for the control object until a target control amount is reached,
Real acceleration detection means for detecting actual acceleration;
When the accelerator depression amount changes in the return direction, the target engine output is output to the target output calculation means based on the actual acceleration detected by the actual acceleration detection means instead of the target acceleration command means. An engine control device comprising: an accelerator return target setting means for providing a target acceleration for calculation. The engine control device according to claim 1 or 2,
The accelerator return target setting means determines that the actual engine output or the actual acceleration is the target engine output or the target acceleration immediately before the accelerator is returned to the target control amount calculating means or the target engine output calculating means. It is configured as a means to give information,
The target acceleration command means is configured as a means for commanding an absolute target acceleration based on the accelerator depression amount, and when the accelerator depression amount is decreased, a relative acceleration decrease amount is calculated based on the decrease amount. An engine control device configured to switch to a commanding means.   4. The engine control apparatus according to claim 3, wherein when the accelerator is depressed again, the accelerator return target setting means is released from its function, and the target acceleration command means is configured to generate an absolute target according to the accelerator depression amount. An engine control device configured to be returned to a means for commanding acceleration.   5. The engine control apparatus according to claim 4, wherein the engine output reaches the target engine output calculated by the target output calculating means when the function of the accelerator return target setting means is canceled by depressing the accelerator again. An engine control apparatus comprising an output increase speed suppression means for suppressing the output increase speed until. In the engine control device according to any one of claims 1 to 5,
The control execution means adjusts the predetermined control signal to an output increasing side so as to maintain the target engine output while a positive acceleration command continues as the target acceleration, and the engine speed during acceleration is increased. An engine control device configured as a means for compensating for a decrease in engine output accompanying an increase in engine power. The engine control apparatus according to claim 6, wherein
Traveling resistance detecting means for detecting traveling resistance applied to the vehicle;
An engine control device, comprising: a running resistance compensation means for increasing an engine output so as to cancel an increase in running resistance caused by acceleration based on the detected running resistance. In the engine control device according to any one of claims 1 to 7,
A linkless throttle that is not mechanically linked to the accelerator and is driven by an actuator;
An engine control device for a gasoline engine vehicle, wherein the control signal is a throttle opening command of the linkless throttle.

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