JP3362265B2 - Engine intake air control system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine intake air amount control device.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Examined Patent Publication 64-6335.
As described in Japanese Patent Laid-Open Publication No. JP-A-2003-264, an engine is provided with an air valve (ISC valve) for idle speed control (ISC) provided in a bypass passage that bypasses the throttle valve of the engine and supplies bypass air, during warm-up operation. In the first idle control, the ISC opening is increased as the engine temperature is lower, and the bypass air amount is increased to increase the idle speed. In addition, apart from that, there is an engine in which the intake pipe effect such as inertia or resonance of the intake system is utilized to enhance the charging efficiency, and such an engine has a large intake volume downstream of the throttle valve. In addition, there is an engine equipped with a mechanical supercharger and performing supercharging control by opening and closing the bypass passage of the supercharger, but in this case as well, a large intake volume due to the bypass passage of the supercharger is located downstream of the throttle valve. Exists.

[0003]

When the amount of air supplied to the engine is increased as the engine temperature is lower by performing the first idle control using the bypass air of the ISC, for example, the inertial effect and the resonance effect are reduced. In an engine with a large intake volume downstream of the throttle valve, such as an engine to be used or an engine equipped with a mechanical supercharger, a large amount of air existing in the intake volume downstream of the throttle valve is sucked into the cylinder at the initial stage of engine startup. Since the amount of air increased by the fast idle control is added to it, when the engine temperature rises to a certain extent, the amount of air supplied to the engine becomes excessive, causing a problem that the engine rotation after the complete explosion rises too much.

The present invention has been made in view of the above problems, and it is possible to prevent excessive rotation blow-up after starting without deteriorating the startability during cold starting. The purpose is to

[0005]

SUMMARY OF THE INVENTION The present invention is a throttle valve.
To the bypass passage that bypasses the bypass air and increases the amount of air supplied to the engine as the engine temperature decreases, and opens the engine when the engine temperature is low.
Air valve that closes when the temperature rises
A device for controlling the volume of intake air engine, in the engine start, and the air when the engine temperature is above the set temperature
The engine temperature is controlled by suppressing the increase of the air volume by the air volume increasing means.
Temperature above the set temperature and the temperature at which the air valve closes
When the temperature exceeds the second preset temperature, which is lower than
It is characterized in that the increase suppression of the air amount by the increasing means is canceled .

The set temperature for suppressing the increase in the air amount is
Even if the increase in the amount of air supplied to the engine at the time of starting is suppressed by the air amount increase suppressing means, it is preferable to set the lower limit of the engine temperature at which the engine can be started with respect to the engine resistance.

[0007]

The amount of air supplied to the engine is increased as the engine temperature becomes lower by the amount-of-air increasing means utilizing the control of the ISC valve, for example, to ensure the warm-up performance during cold. Further, when the engine is being started and the engine temperature is equal to or higher than the set temperature, the increase in the air amount is suppressed by closing the ISC valve, for example, so that the air existing in the intake volume downstream of the throttle valve is reduced in the initial stage of starting. Even if a large amount is sucked into the cylinder,
It is prevented that the amount of air becomes excessive and the engine rotation after the complete explosion rises significantly.

Further , in an engine in which an air valve for bypass air supply, which opens when the engine temperature is low and closes when the engine temperature rises, is attached to an air amount increasing means such as an ISC valve, the temperature for suppressing the increase in air amount is increased. By limiting the range between the preset temperature and the second preset temperature lower than the closing temperature of the air valve, the bypass air amount may become smaller than the set amount due to the variation of the air valve. The suppression is lifted,
As a result, a start-up failure due to an insufficient amount of air during warming is prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG . 1 is an overall system diagram of an embodiment of the present invention. The engine 1 of this embodiment is a V-type multi-cylinder, and the independent intake passages 2a, 2b of the cylinders of the left and right banks are formed to branch from the independent surge tanks 3A, 3B for each bank. In addition, each surge tank 3A, 3B
The inlet side is connected to one upstream intake passage 5 connected to the air cleaner 4 via branch passages 6A and 6B, respectively. An air flow sensor 7 is arranged downstream of the air cleaner 4 in the upstream intake passage 5, a resonator 8 is arranged downstream thereof, a throttle valve 9 is arranged downstream of the resonator 8, and a mechanical valve is arranged further downstream thereof. Feeder 1
0 is set. In addition, a supercharger bypass passage 11 that connects the upstream side of the upstream intake passage 5 to the upstream side of the supercharger 10 and the downstream side of the supercharger 10 so as to bypass the mechanical supercharger 10 with respect to the upstream intake passage 5. A bypass valve (AB provided with a diaphragm type actuator 12 is provided in the middle of the passage.
V) 13 is installed.

[0011] The actuator 12 is a obtained by partitioning the operating negative pressure chamber 12c and the atmospheric chamber 12b by the diaphragm 12a, the diaphragm 12a atmospheric chamber 1
A valve shaft of the bypass valve 13 is connected to the 2b side, and a spring 14 is arranged on the operating negative pressure chamber 12c side so as to constantly urge the diaphragm 12a in the valve closing direction. An operating negative pressure introducing passage 15 for introducing an operating negative pressure is provided in the operating negative pressure chamber 12c of the actuator 12, and an upstream of the operating negative pressure introducing passage 15 is provided with a negative pressure source (vacuum pump) not shown. A first duty solenoid valve 16A that controls introduction of negative pressure and a second duty solenoid valve 16B that controls introduction of atmospheric pressure upstream of the throttle from the resonator are arranged.

Further, each of the surge tanks 3A, 3B of the inlet side to the connected branch passages 6A, each of the 6B intercooler 17A, 17B are installed. Then, the supercharger bypass passage 11 bypassing the mechanical supercharger 10 is branched from the downstream side of the bypass valve 13 to form each branch passage 6A,
The intercooler bypass passages 18A, 18B communicating with the downstream sides of the intercoolers 17A, 17B of 6B are provided, and the supercharger bypass passage 11 joins the upstream intake passage 5 on the downstream side of the supercharger 10 at a downstream confluence point. An intercooler bypass valve 19 that switches the flow of bypass air between the intercooler 17A and 17B side and the intercooler bypass passages 18A and 18B side is installed in the vicinity.
The intercooler bypass valve 19 is driven to open and close by a diaphragm type actuator 20,
It is configured to open normally and close when negative pressure is introduced to the actuator 20 via the three-way solenoid valve 21.

When the engine load is low, the bypass valve 13 provided in the supercharger bypass passage 11 is opened and the intercooler bypass valve 19 is opened. This time,
The air from the air cleaner 4 bypasses the mechanical supercharger 10 and bypasses the intercoolers 17A and 17B, and flows into the surge tanks 3A and 3B of each bank. Further, when the engine load is high, the bypass valve 13 is closed and the intercooler bypass valve 19 is closed. At this time, the air entered from the air cleaner 4 flows into the mechanical supercharger 10 and is pressurized, and is sent to the surge tanks 3A and 3B of each bank through the intercoolers 17A and 17B.

Further , the upstream intake passage 5 has two throttle bypass passages, a first bypass throttle passage 9 and a second throttle bypass passage 2 for bypassing the throttle valve 9 and connecting the resonator 8 and the upstream of the supercharger 10.
2, 23 are provided. In the first throttle bypass passage 22, a solenoid valve (ISC valve) 24 for duty control and a wax type which opens when the engine water temperature is low and opens when the engine temperature rises to a set temperature (for example, 80 ° C). A bypass air control valve 26 in which the air valve 25 and the air valve 25 are arranged in parallel is provided. In addition, the second throttle bypass passage 23 has an air conditioner,
An idle-up solenoid valve 27 is provided which opens when power steering or the like operates.

[0015] Each cylinder of the engine 1, an intake valve 29 and the exhaust valve 30 is provided in each combustion chamber 28, also the ignition device 31, each independent intake passage 2A, fuel injection valve for supplying fuel to 2B 32 is provided.

The engine 1 is equipped with an engine control unit 33 composed of a microcomputer. In addition to the intake air amount signal from the air flow sensor 7, various signals such as an engine speed signal, an engine water temperature signal, a boost pressure signal, a throttle opening signal, and a starter switch signal are input, and the fuel injection amount and the ignition timing are input. Is performed, ABV control is performed by the first and second duty solenoid valves 16A and 16B, the three-way solenoid valve 21 is controlled, and
ISC valve 24, idle up solenoid valve 27
Etc. are controlled.

The intake pressure (boost pressure) of the ABV (bypass valve) 13 is a predetermined negative pressure (for example, −200 mmHg).
With the above, it is gradually closed and a predetermined positive pressure (for example, +200 mm
It is controlled to be fully closed by Hg).

Further, the opening of the ISC valve 24 is increased to promote warm-up during cold engine resistance,
The opening degree is controlled based on a predetermined characteristic map so that the bypass air amount is increased as the water temperature is lower. However, at the time of starting and when the water temperature becomes higher than 0 ° C, the opening operation of the ISC valve 24 is prohibited and the valve is fully closed in order to prevent the amount of air from becoming excessive and the rotation blow-up after starting to increase. To be done. Further, when the water temperature further rises to 50 ° C. or higher, the opening operation of the ISC valve 24 is prohibited so that the insufficient amount of air due to the variation of the wax type air valve 25 will not cause a start failure. Is released and the opening is returned to the opening based on the characteristic map. FIG. 2 shows the opening characteristic of the ISC valve 24 according to the engine water temperature.

FIG . 3 is a flow chart for executing the control of the ISC valve of this embodiment. This flowchart consists of steps S1 to S12.
1 reads various signals. Then, in S2, it is determined whether or not the starter switch is ON. If the starter switch is ON, the engine water temperature will be 0 in S3.
If the water temperature exceeds 0 ° C, check whether the water temperature has reached 50 ° C in S4. When the determinations at S3 and S4 are both YES and the water temperature is higher than 0 ° C and lower than 50 ° C, the process proceeds to S5 to set the ISC control amount to 0 (zero),
In S6, a fully closed signal is output to the ISC valve.

Even if the starter switch is ON in S2, if the determination in S3 or S4 is NO and the engine water temperature is 0 ° C. or lower or 50 ° C. or higher, the process proceeds to S7. At this time, the determination in S7 is NO, and the process proceeds to S12, which will be described later, to set the ISC control amount to a fixed value G according to the operating state. Here, the control amount G is set to be the ISC valve opening degree according to the water temperature according to the characteristic map of FIG.

Further, unless the starter switch ON in S2, determines whether at engine idle in S7, if idle, the target idle speed N ₀ in accordance with the water temperature at S8. Then, in S9, the ISC basic control amount G _B according to the target idle speed N ₀ is set, in S10, the feedback correction amount G _FB based on the deviation between the actual engine speed and the target idle speed is obtained, and in S11. The final control amount G of ISC is determined by correcting the basic control amount G _B with the feedback correction amount G _FB . And
In S6, the ISC control signal corresponding to the final control amount G is set to I
Output to SC valve.

Further, when it is determined not idle in S7, the process proceeds to S12, a fixed value G corresponding to ISC control quantity on the operating state, and outputs the ISC valve at S6.

In the above embodiment, the amount of air is increased by controlling the ISC valve when it is cold, and the amount of air increase is prohibited when the engine water temperature is between 0 ° C and 50 ° C. However, the air amount increase and the increase prohibition are not limited to those by controlling the ISC valve. Also, the temperature range in which the increase in the amount of air is prohibited can be changed as appropriate.

[0024]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it is possible to increase the amount of air for fast idle at the cold start when the engine resistance is large and to secure the warm-up performance, and the engine temperature Even if a large amount of air existing in the intake volume downstream of the throttle valve is sucked into the cylinder at the time of starting in a somewhat high state, the amount of air becomes excessive and the engine rotation after the complete explosion rises significantly. Can be prevented.

Further , in an engine provided with an air amount increasing means, an air valve for bypass air supply, which opens when the engine temperature is low and closes when the engine temperature becomes high, even if there is variation in the air valve, By releasing the suppression of the air amount, it is possible to prevent the start-up failure due to the insufficient air amount in the warm region.

[Brief description of drawings]

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

FIG. 2 is a control characteristic diagram of the ISC valve opening according to the water temperature in one embodiment of the present invention.

FIG. 3 is a flowchart for executing control of the ISC valve according to the embodiment of the present invention.

[Explanation of symbols]

1 engine 22 First throttle bypass passage 23 Second throttle bypass passage 24 Air valve (ISC valve) 25 Air valve (wax type) 26 Bypass air control valve 27 Idle-up solenoid valve 33 Engine control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-135631 (JP, A) JP 1-190941 (JP, A) JP 56-165739 (JP, A) JP 1- 100332 (JP, A) JP 59-136538 (JP, A) Actual development 59-116550 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 41/00-41 / 40

Claims (2)

(57) [Claims] 1. A bypass air is bypassed to bypass a throttle valve.
Air amount increasing means and engine for increasing the amount of air supplied to the engine as the engine temperature is lower in the bypass passage to be supplied
Open when the temperature is low and close when the engine temperature is high
Intake air amount control device for an engine equipped with an air valve
The engine temperature is higher than the preset temperature when the engine temperature is higher than the preset temperature while the engine is starting and the engine temperature is equal to or higher than the preset temperature.
A second preset temperature lower than the temperature at which the air valve is closed
When it becomes higher, the air amount is increased by the air amount increasing means.
An intake air amount control device for an engine, which releases the amount restriction . 2. The set temperature is set to the lower limit of the engine temperature at which the engine can be started with respect to the engine resistance even if the increase in the amount of air supplied to the engine at the time of starting is suppressed by the air amount increase suppressing means. The intake air amount control device for the engine according to claim 1.