JPH0419338A - Engine output controller of four wheel drive vehicle - Google Patents

Abstract

PURPOSE:To improve power characteristics of a vehicle at the time of four- wheel drive by providing a supercharge range change means which changes a supercharge range so that an operation range of a supercharger is widen more to the side of low load at the time of four-wheel driving than the case at the time of two-wheel drive. CONSTITUTION:In an engine provided with a mechanical supercharger 2, a supercharge operation means 3 such as an electromagnetic clutch which actuates the mechanical supercharger 2 in a specified operation range, a driving changeover system 6 which carries out changeover from the two-wheel driving mode with front wheels 4 or rear wheels 5, to the four-wheel driving mode with the front and rear wheels 4, 4, 5, 5 and vice versa control means 7 which receives an output signal of a driving mode detection means 8 which detects the driving mode according to a signal from the driving mode changeover system 6 is provided. The supercharge range is changed over by a supercharge range changeover means 9 based on the detected driving mode. When the four-wheel driving mode is detected, enlargement of the supercharge range is secured. A stable drivability at the time of the four-wheel driving is thereby ensured to the mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine output control device for a four-wheel drive vehicle equipped with a supercharged engine.

(Prior art) In 4-wheel drive vehicles that use a clutch to switch between 2-wheel drive and 4-wheel drive, the drive loss is generally greater during 4-wheel drive compared to 2-wheel drive, so it is difficult to maintain the same accelerator opening. On the other hand, it has been known for a long time that when the vehicle is in four-wheel drive, it is necessary to perform control to increase the engine output to prevent the driving feeling from deteriorating.

The engine control device disclosed in Japanese Patent Application Laid-Open No. 60-30433 discloses an example of engine control based on the above-mentioned requests. That is, in the publication, when switching from two-wheel drive to four-wheel drive, the engine output is increased by correcting and controlling the fuel injection amount, ignition timing, throttle valve opening, etc. The publication also proposes, in the case of a supercharged engine, to perform correction control of the engine output by controlling supercharging pressure.

(Problem to be solved by the invention) Four-wheel drive has superior running stability compared to two-wheel drive. For example, even if you step on the accelerator in the same way, four-wheel drive will not be able to run stably even under extremely bad conditions. It is possible. on the other hand,
Two-wheel drive has a problem in that it is suitable for normal driving because the driving resistance is low, but it is prone to slipping if too much torque is applied. Therefore, in a device that switches between two-wheel drive and four-wheel drive, various output controls are required depending on each case. However, conventional control devices
Although the engine output is controlled to prevent deterioration of driving feeling due to switching as described above,
Beyond that, there was no attempt to actively improve the vehicle's power performance when in four-wheel drive.

Therefore, especially in the case of a four-wheel drive vehicle equipped with a supercharged engine, a supercharging control system that can make maximum use of the stable running performance of four-wheel drive is required.

Additionally, in the case of a four-wheel drive vehicle that controls the distribution of driving force to the front wheels and rear wheels, in addition to the above problems or issues, due to changes in driving resistance due to the distribution of driving force, the vehicle response to the same accelerator operation may be affected. In addition, if the steering characteristics change suddenly or the vehicle accelerates or decelerates inadvertently in the parking area, the deterioration of the driving feeling becomes even more noticeable, so countermeasures are necessary.

The present invention has been made in view of the above circumstances and problems, and is particularly applicable to four-wheel drive vehicles that are equipped with a supercharged engine and switch between two-wheel drive and four-wheel drive.
The purpose is to improve the power performance of vehicles when driven by wheels.

Further, the present invention similarly relates to a four-wheel drive vehicle equipped with a supercharger, in particular a vehicle equipped with a driving force distribution control device that controls driving force distribution to front wheels and rear wheels. The purpose is to maximize the power performance of a vehicle according to the distribution ratio, and to prevent deterioration in driving feeling caused by changes in the driving force distribution ratio.

(Means for Solving the Problems) The engine output control device for a four-wheel drive vehicle according to the present invention firstly includes a supercharger and a supercharger operating means for operating the supercharger in a predetermined supercharging region. In addition to being equipped with an engine that has
A four-wheel drive vehicle equipped with a drive system switching mechanism that switches between two-wheel drive and four-wheel drive includes a drive system detection means for detecting the drive system, and receives the output of the drive system detection means to switch between two-wheel drive and four-wheel drive. The present invention is characterized in that a supercharging region changing means is provided for changing the supercharging region so as to widen the operating region of the supercharger to a low-load flight from time to time.

Second, the engine output control device for a four-wheel drive vehicle according to the present invention is equipped with an engine having a supercharger and a supercharger operating means for operating the supercharger in a predetermined supercharging region. , a four-wheel drive vehicle equipped with a driving force distribution control means for controlling driving force distribution to front wheels and rear wheels, a driving force distribution ratio detection means for detecting a driving force distribution ratio by the driving force distribution control means; Receiving the output of the driving force distribution ratio detection means,
The present invention is characterized in that a switching line changing means is provided for changing the switching line that defines the supercharging region in accordance with the driving force distribution ratio.

Thirdly, the engine output control device for a four-wheel drive vehicle according to the present invention is equipped with an engine having a supercharger and a boost pressure changing means for changing the maximum boost pressure of the supercharger, and
In a four-wheel drive vehicle equipped with a driving force distribution control means for controlling the distribution of driving force to front wheels and rear wheels, a driving force distribution ratio detection means for detecting a driving force distribution ratio by the driving force distribution control means; The present invention is characterized in that a supercharging pressure changing means is provided which receives the output of the distribution ratio detection means and changes the maximum supercharging pressure according to the driving force distribution ratio.

(Function) In a four-wheel drive vehicle equipped with a drive system switching mechanism that switches between two-wheel drive and four-wheel drive, when the drive system detection means detects that the drive system has been switched from two-wheel drive to four-wheel drive. The supercharging region is changed by the supercharging region changing means so as to expand toward the lower load side. This improves power performance during four-wheel drive, and prevents deterioration in driving feeling due to the difference in drive resistance between four-wheel drive and two-wheel drive.

Further, in a four-wheel drive vehicle equipped with a driving force distribution control means for controlling the driving force distribution to the front wheels and the rear wheels, the driving force distribution ratio detection means detects the driving force distribution ratio between the front wheels and the rear wheels. Then, the switching line defining the supercharging region is changed according to the detected driving force distribution ratio. As a result, power performance is improved in accordance with the driving force distribution ratio, and deterioration of driving feeling caused by changes in the driving force distribution ratio is prevented.

In addition, in a four-wheel drive vehicle equipped with a driving force distribution control means that controls the driving force distribution to the front wheels and rear wheels, the maximum supercharger By changing the supercharging pressure, the power performance is also increased according to the driving force distribution ratio, and deterioration of the driving feeling due to the difference in driving resistance is prevented.

(Example) Examples will be described below based on the drawings.

FIG. 1 is a system diagram of an embodiment of the present invention.

The engine of the automobile 1 according to this embodiment includes a mechanical supercharger 2 and a supercharger operating means 3 for operating the mechanical supercharger 2 in a predetermined supercharging region. The supercharger operating means 3 is constituted by an electromagnetic clutch (not shown). By engaging the electromagnetic clutch, the mechanical supercharger 2 is drivingly connected to the output shaft of the ENON, and the engine is supercharged. The automobile 1 also includes a drive system switching mechanism 6 that switches between two-wheel drive using either the front wheels 4 or rear wheels 5 and four-wheel drive using the front wheels 4 and rear wheels 5. This drive method switching mechanism 6 is constituted by a pair of clutches (not shown).

These clutches are arranged between a gear mechanism connected to the transmission output shaft and each differential on the front wheel 4 side and the rear wheel 5 side. When either one of these clutches is engaged, the vehicle becomes a two-wheel drive state, and when both clutches are engaged, the vehicle becomes a four-wheel drive state.

In this embodiment, the drive system is detected, and when the vehicle is in four-wheel drive, two
Control is performed to widen the supercharging range compared to wheel drive. Therefore, the control means 7 consisting of a microcomputer includes a drive method detection means 8 that detects the drive method based on the signal from the drive method switching mechanism 6, and a supercharging system that changes the supercharging area based on the detected drive method. Area changing means 9 is provided. When four-wheel drive is detected, the supercharging region is expanded as shown in the change from FIG. 2(a) to FIG. 2(b).

The supercharging range is set by engine speed and load. That is, with a predetermined engine rotational speed and load as a switching line, the supercharger operates at a higher rotational speed or higher load side to supercharge the engine. and,
As shown by the shaded area in Figure 2, the setting of the supercharging region changes from (a) in the figure when two-wheel drive is used, to (b) in the same figure when the drive is four-wheel drive, mainly on the low-load side. will be expanded to.

FIG. 3 is a flowchart of control for changing the supercharging region.

When the car starts, it first determines whether the two-wheel drive is active. If YES, that is, 2-wheel drive, see Figure 2 (
Use the supercharging area of a).

Also, if NO, it means 4-wheel drive, as shown in Figure 2 (
Use the supercharging area of b).

FIG. 4 is a system diagram of another embodiment of the present invention. In this embodiment, the engine of the automobile 1 has a mechanical supercharger 2 and a supercharger operating means 3 for operating the mechanical supercharger 2 in a predetermined area, as in the previous embodiment. There is. The supercharger operating means 3 is also constituted by an electromagnetic clutch. Then, by engaging the electromagnetic clutch, the mechanical supercharger 2 is driven by the engine, and supercharging is performed.

Further, in the case of this embodiment, the distribution of driving force to the front wheels 4 and rear wheels 5 of the automobile 1 is linearly controlled.

As in the previous embodiment, the driving force distribution control device IO for this purpose is constituted by a gear mechanism connected to the transmission and clutches respectively disposed between the differential on the front wheel 4 side and the differential on the rear wheel 5 side. Ru. The coupling forces of these clutches are then controlled based on a required driving force distribution ratio.

In this embodiment, the load level (switching line) that defines the supercharging region is linearly changed according to the driving force distribution ratio. Therefore, the control means 7 includes a driving force distribution ratio detection means ll for detecting the driving force distribution ratio by the driving force distribution control device 10, and a supercharging means for changing the switching line based on the detected driving force distribution ratio. Mechanism switching line changing means 12 is provided.

When the driving force distribution ratio between the front wheels 4 and the rear wheels 5 is 100:0 or O:100, the vehicle is in a two-wheel drive state. Further, when the driving force distribution ratio is evenly distributed at 50:50, it is a normal four-wheel drive state. Then, the supercharging region, which is also set based on the engine speed and load, is changed according to the driving force distribution ratio.

In other words, the load level, which is the switching line for the supercharging region, changes the driving force distribution from two-wheel drive (2WD) to four-wheel drive (4WD).
As the load approaches , the load is changed to the low side as shown in FIG. 5, and the supercharging area corresponding to the shaded area in the figure is linearly expanded.

FIG. 6 is a system diagram of yet another embodiment. In this embodiment, the automobile 1 is also equipped with an engine having a mechanical supercharger 2, and the distribution of driving force to the front wheels 4 and rear wheels 5 is controlled as in the embodiment shown in FIG. The driving force distribution control device 10 is provided. Further, driving force distribution ratio detection means +1 for detecting the driving force distribution ratio between the front wheels 4 and the rear wheels 5 is also provided. Further, a supercharging pressure changing means 13 for changing the maximum supercharging pressure of the mechanical supercharger 2 by controlling the opening of a control valve (not shown) is provided, and this supercharging pressure changing means 13 or the driving force distribution ratio detecting means 11
It is configured to be controlled by the control means 7 based on the output of.

The driving resistance is greatest in a four-wheel drive state where the driving force distribution ratio between the front wheels 4 and rear wheels 5 is equally distributed (50.50), and when the driving force distribution ratio between the front wheels 4 and rear wheels 5 is 100. O:
When the ratio is 100, the drive resistance is approximately half that of the equal distribution ratio, and since the drive resistance changes during that time, as shown in Figure 7, the front wheel drive peaks when the drive force distribution ratio is 50:50. On the (FF) side and the rear wheel drive (PR) side, control is performed to lower the maximum boost pressure using the respective maps (a, b). This prevents changes in vehicle responsiveness depending on the driving force distribution ratio, sudden changes in steering characteristics when the accelerator is turned ON and OFF during turns, and involuntary acceleration and deceleration of the vehicle in a partial range.

FIG. 8 is a flowchart of the above-mentioned supercharging pressure change control.

When the vehicle starts, it is first determined whether the drive distribution ratio is toward the front wheels 4 or not. And YES (front wheel closer to 4)
If so, select the map sheet marked with & in Fig. 7. If no, then check whether the drive distribution ratio is closer to rear wheel 5, and if yes, select map zone b. Moreover, if NO, the process returns.

The Nostem shown in Fig. 6 also allows control such as this to achieve unique driving performance.

For example, if too much driving force is applied to the front wheels 4 when the driving force distribution ratio is closer to the front wheels 4, there is a problem that the front wheels 4 will slip during a corner and understeer will increase. If the main focus is on reducing the maximum boost pressure, as shown in Figure 9, supercharging pressure reduction control should be performed only on the FF side, so that the maximum boost pressure decreases as the driving force distribution ratio approaches the FF side from uniform distribution. conduct. That is,
As shown in the flowchart in Figure 1O, the driving force distribution ratio is
It is determined whether the front wheels are closer to each other, and if the front wheels are closer to 4, the map zone e in FIG. 9 is selected.

On the other hand, if too much driving force is applied to the rear wheels when the drive horn distribution ratio is closer to the rear wheel 5, there is a problem that the rear wheels 5 will slip during a corner and oversteer will increase. When the main focus is to prevent an increase in steering, supercharging is performed only on the FR side, as shown in Figure 11, so that the maximum supercharging pressure decreases as the driving force distribution ratio approaches the FR side from equal distribution. Performs pressure reduction control. That is,
As shown in the flowchart in Figure 12, the driving force distribution ratio is 5 for the rear wheels.
If the rear wheel is closer to 5, select map zone f in Fig. 11.

Next, an intake air cooling system that cools the high-temperature air compressed by the mechanical supercharger 2 will be described in relation to each of the above embodiments.

First, in the example shown in FIG. 13, an intake passage 103 that communicates an intake manifold 101 and an air cleaner 102 of an engine 100 is connected to a main passage 105 in which a mechanical supercharger 2 is disposed downstream of a throttle valve 104, and a relief passage 1.
It is branched into 06. A control valve 107 is arranged at the branch portion. In addition, the above main passage 1
05 is branched into two passages 105a and 105b, a first passage and a second passage 105b, downstream of the mechanical supercharger 2, and the first passage i.

An air-cooled intercooler 108 is disposed in the passage 5a, and a water-cooled intercooler 109 is disposed in the second passage 105b. The first and second passages 105a, l
An intercooler switching valve 110 is provided at the branch section 05b.

Cooling water cooled by a subradiator 111 is circulated through the water-cooled intercooler 109 via a water tank 112 and a water pump 113.

The above intercooler switching valve +10 is an intercooler switching valve operating means (actuator)
114 and selectively sends the air compressed by the mechanical supercharger 2 to the air-cooled intercooler 108 or the water-cooled intercooler 109. Therefore, the control means 115 consisting of a microcomputer receives a vehicle speed signal from the vehicle speed detection means 116, a water amount signal from the cooler water amount detection means +17 that detects the amount of water in the water tank +12, and a water temperature signal from the cooler water temperature detection means +18. signal and
An intake temperature signal from the intake temperature detection means +19, a load signal from the engine state detection means 120, etc. are given as information. Then, switching control is performed according to the flow shown in FIG.

That is, when starting, first check whether the water intercooler 109 is normal, that is, whether there are any abnormalities such as the cooler water amount being lower than a predetermined value or the cooler water temperature being lower than a predetermined value (freezing). If so, select the air intercooler 108. Also,
If it is normal, then it is checked whether the intake air temperature is extremely low, and if it is extremely low, it is switched to the water-cooled intercooler 109 to warm the intake air.

If the water-cooled intercooler 109 is normal and the intake temperature is not extremely low, then check whether the vehicle speed is low or not, and if it is not low, the air-cooled intercooler 10
Apply 8. Also, at low speeds, the air-cooled intercooler +08 is less effective, so check whether the load is low or not, and unless the load is low, use the water-cooled intercooler 10.
Apply 9. Also, if the load is low, combustibility will be better if it is not too cold, so air-cooled intercooler 1
Switch to 08.

Next, the example shown in FIG. 15 will be explained. In this case as well, the intake passage 103 that communicates the intake manifold 101 of the engine +00 with the air cleaner 102 is connected to the throttle valve 1.
04 downstream, it branches into a main passage 105 in which the mechanical supercharger 2 is arranged and a relief passage +06, and a control valve 107 is arranged at the upstream branch. Also,
In the main passage 105, a water-cooled intercooler 109 and an air-cooled intercooler 108 are arranged in series from the upstream side, and a bypass passage 105c that bypasses the water-cooled intercooler 109 and the bypass passage 10
A communication passage 105d is provided that communicates the relief passage with a position between both intercoolers 108 and 109 where the intercoolers 5c join together. A first intercooler switching/club 110a is provided at the upstream branch position of the bypass passage 105c, and both intercoolers 1
At the branch position of the communication path 105d between 08 and 109,
0 on the air-cooled intercooler 108 side is the communication path 105d
A second intercooler switching valve 110b that selectively opens and closes the intercooler is provided. Cooling water power (circulated via a water tank 112 and a water pump 113) also cooled by a subradiator 111 is supplied to the water-cooled intercooler 109.

The first and second intercooler switching valves +10a, 110b are operated by intercooler switching valve operating means (actuator) 114. Therefore, the control means 115 consisting of a microcomputer also receives a single speed signal from the vehicle speed detection means 116, a water amount signal from the cooler water amount detection means 117 that detects the amount of water in the water tank 112, and a cooler water temperature detection means 118. Water temperature signal from and intake temperature detection means 1
Intake temperature signal from 19 and engine condition detection means 120
The water temperature signal and load signal from are given as information. In this example, switching control between the air-cooled intercooler 108 and the water-cooled intercooler 109 is performed as follows according to the flow shown in FIG. Here, when the first intercooler switching valve 110a is opened to the water-cooled intercooler 109 side and the second intercooler switching valve 110b is opened to the air-cooled intercooler 108 side, the air compressed by the mechanical supercharger 2 is water-cooled. It passes through intercooler 109 and air-cooled intercooler 108.

And the first intercooler switching valve 110
a is opened to the water-cooled intercooler 109 side, and the second intercooler switching valve 110b is connected to the communication path 105d.
When it is opened to the side, air compressed by the mechanical supercharger 2 passes only through the water-cooled intercooler 109. Also, the first
When the intercooler switching valve 110a is opened to the bypass passage 105c side and the second intercooler switching valve 110b is opened to the air-cooled intercooler 108 side, the air compressed by the mechanical supercharger 2 is transferred only to the air-cooled intercooler 108. pass through. In addition,
The flow in FIG. 16 also includes bypass control by the control valve 107.

When started, first, it is determined whether the engine water temperature is lower than a predetermined value based on the output of the engine state detection means. If the water temperature is lower than the specified value,
The control valve 107 opens the relief passage +06 side to bypass the mechanical supercharger 2 and both intercoolers 108 and 109 to perform intake. If the water temperature is not low, then check whether the water intercooler 109 is normal, that is, whether there are any abnormalities such as the cooler water volume being lower than a predetermined value or the cooler water temperature being lower than a predetermined value (freezing). Check the air intercooler 108 and select the air intercooler 108 if it is abnormal. If it is normal, then it is checked whether the intake air temperature is extremely low, and if it is, the system switches to the water-cooled intercooler 109 to warm the intake air.

If the water-cooled intercooler 109 is normal and the intake temperature is not extremely low, then check whether the load is extremely high and if the load is extremely high, the air-cooled intercooler 108
and water-cooled intercooler 109. Also,
When the load is not extremely high, next check whether the vehicle speed is low or low, and if the speed is not low, turn on the air-cooled intercooler 108. Also, when the speed is low, check to see if the load is high, and if the load is high, use the water-cooled intercooler 10.
9, and if the load is not high, switch to the air-cooled intercooler 108 to improve combustibility.

(Effects of the Invention) Since the present invention is configured as described above, the supercharging range can be expanded in a four-wheel drive state with good running stability, and the power performance of the vehicle can be actively improved.

In addition, by changing the supercharging area or changing the maximum boost pressure according to the drive power distribution ratio between the front wheels and rear wheels, the power performance of the vehicle can be improved according to the drive power distribution, and the drive power Deterioration of driving feeling due to changes in distribution ratio can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of one embodiment of the present invention, and Fig. 2 is a system diagram of an embodiment of the present invention.
The characteristic diagram of the embodiment shown in the figure, Figure 3 is the same flowchart, and Figure 4 is the same flowchart.
The figure is a system diagram of another embodiment, FIG. 5 is a characteristic diagram of the embodiment of FIG. 4, FIG. 6 is a system diagram of yet another embodiment, and FIG. 7 is a characteristic diagram of the embodiment of FIG. 6. , FIG. 8 is the same flowchart, FIG. 9 is a characteristic diagram of another embodiment according to FIG. 6, FIG. 1O is the same flowchart, and FIG. 11 is a characteristic diagram of another embodiment according to FIG. 6. , FIG. 12 is the same flowchart, FIG. 13 is a system diagram showing an example of the intake air cooling system in each of the above embodiments, FIG. 14 is the same flowchart, and FIG. 15 is a system diagram showing another example of the same intake air cooling system. , FIG. 16 is the same flowchart. l: automobile, 2: mechanical supercharger, 3: supercharger operating means,
4: Front wheel, 5 Rear wheel, 6: Drive system switching mechanism, 72 Control means, 8: Drive system detection means, 9: Supercharging area changing means,
10. Driving force distribution control device, 11: driving force distribution ratio detection means, I2: supercharger operation switching line changing means, 13: supercharging pressure changing means.

Claims (3)

[Claims] (1) Equipped with an engine having a supercharger and a supercharger operating means for operating the supercharger in a predetermined supercharging region,
A four-wheel drive vehicle equipped with a drive system switching mechanism that switches between two-wheel drive and four-wheel drive includes a drive system detection means for detecting the drive system, and receives the output of the drive system detection means to switch between two-wheel drive and four-wheel drive. An engine output control device for a four-wheel drive vehicle, characterized in that a supercharging region changing means is provided for changing the supercharging region so as to gradually expand the operating region of the supercharger to a lower load side. (2) Equipped with an engine having a supercharger and a supercharger operating means for operating the supercharger in a predetermined supercharging region,
In a four-wheel drive vehicle equipped with a driving force distribution control means for controlling driving force distribution to front wheels and rear wheels, a driving force distribution ratio detection means for detecting a driving force distribution ratio by the driving force distribution control means; Engine output control for a four-wheel drive vehicle, characterized in that switching line changing means receives the output of the force distribution ratio detection means and changes the switching line defining the supercharging region according to the driving force distribution ratio. Device. (3) Equipped with an engine having a supercharger and a supercharging pressure changing means for changing the maximum supercharging pressure of the supercharger, and a driving force distribution control means for controlling the distribution of driving force to the front wheels and rear wheels. In the four-wheel drive vehicle, the driving force distribution ratio detecting means detects the driving force distribution ratio by the driving force distribution control means, and the maximum boost pressure is adjusted to the driving force distribution ratio by receiving the output of the driving force distribution ratio detecting means. An engine output control device for a four-wheel drive vehicle, characterized in that it is provided with a supercharging pressure changing means that changes it according to a force distribution ratio.