JPH0968028A - Blow-by gas control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the blow-by gas flow to a required minimum by inputting a detection signal of a pressure sensor, the intake pipe pressure of an intake passage, and a detection signal of engine speed to a control means, and feedback-controlling the opened state of a solenoid valve with the duty value so as to put the inside of a crankcase in a negative pressure state. SOLUTION: A solenoid valve 28 is provided at the intermediate part of a second communicating passage 18 for communicating a second space part 14 of a crankcase 8 with an intake passage 4 downstream of a throttle valve 6, and a pressure sensor 30 is provided to detect the pressure in the crankcase 8. A detection signal from the pressure sensor 30, the intake pipe pressure of an intake passage 4, and a detection signal of engine speed from an engine speed sensor are inputted to a control means 32, and the opened state of the solenoid valve 28 is feedback-controlled with the duty value so as to put the inside of the crankcase 8 in a negative pressure state. The blow-by gas flow is thereby reduced to a required minimum to improve a combustion condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas control device for an internal combustion engine, and more particularly, to controlling a blow-by gas to a negative pressure state in a crankcase by a control means to minimize a blow-by gas flow rate and improve a combustion state. At the same time, the present invention relates to a blow-by gas control device for an internal combustion engine, which performs feedback control of an open state of a solenoid valve by a control means during deceleration to reliably control a flow rate of blow-by gas during deceleration.

[0002]

2. Description of the Related Art In an internal combustion engine, when burning fuel, exhaust gas in a combustion chamber leaks into a crankcase from a gap between pistons and becomes blow-by gas. This blow-by gas is returned to the combustion chamber of the internal combustion engine again without being discharged to the atmosphere.

As a blow-by gas control device for the internal combustion engine, there is one disclosed in Japanese Utility Model Laid-Open No. 5-87211. The blow-by gas processing device in the internal combustion engine disclosed in this publication has the following structure in the first blow-by gas passage:
While the throttle orifice or the check valve is provided, when the intake negative pressure downstream of the throttle valve in the second blow-by gas passage is small toward the atmospheric pressure side, the passage cross-sectional area of the second blow-by gas passage is increased to increase the intake negative pressure. The flow control valve is designed to reduce the passage cross-sectional area of the second blow-by gas passage as it becomes larger on the vacuum side to reduce the amount of oil that disappears together with the blow-by gas in the high load operating range, and to use as a throttle valve. The occurrence of icing is reduced.

[0004]

In the conventional blow-by gas control device for an internal combustion engine, the internal combustion engine 102 has an internal space 110 as shown in FIG.
This internal space 110 is a first space portion 1 that is a separator chamber that accommodates a separator 152 above the internal combustion engine 102.
12 and the crankcase 108 at the bottom of the internal combustion engine 102.
It is composed of a second space 114 which is a crank chamber formed inside.

A first communication passage 116 for connecting the second space 114 of the crankcase 108 and the intake passage 104 upstream of the throttle valve 106 is provided, and the second space 114 of the crankcase 108 and the throttle valve 106 are provided. A second communication passage 118 communicating with the intake passage 104 on the downstream side is provided.

The first communication passage 116 includes an intake passage 104 upstream of the throttle valve 106 and a first space 112.
First formed in the breather hose 120 for connecting to
The passage 122, the first space 112 and the second space 11
2 formed inside the internal combustion engine 102 to communicate with
And a passage 154.

The second communication passage 118 is formed by the intake passage 104 on the downstream side of the throttle valve 106 and the first space portion 11.
From the third passage 126 formed in the connecting member 124 connecting the two and the fourth passage 156 formed inside the internal combustion engine 102 to connect the first space 112 and the second space 114. Become.

On the way of the second communication passage 118, that is, the first
A PCV valve 158 is provided in the middle of the passage 122.

The air is sucked into the second space 114 of the crankcase 108 by utilizing the pressure of the intake pipe in the intake passage 104, and the second space 1 of the crankcase 108 is drawn.
The blow-by gas in 14 is fed to a combustion chamber (not shown) of the internal combustion engine 102.

At this time, it is the PCV valve 158 that adjusts the blow-by gas flow rate. As shown in FIG. 6, the PCV valve 158 has a structure in which the valve body 160 is pressed by a spring 162, and the amount of leakage between the valve body 160 and the seat portion 164 and the spring 16 are increased.
The flow rate characteristic is determined by the strength of the biasing force of 2.

This flow rate characteristic cannot be set finely because of its structure, and as shown in FIG. 7, it must be set to a value slightly smaller than the required minimum flow rate. Further, the required minimum flow rate is the minimum flow rate of blow-by gas at which the crankcase does not have positive pressure.

As a result, in the adjustment of the blow-by gas flow rate by the PCV valve, the blow-by gas of a required minimum flow rate or more is sent to the combustion chamber of the internal combustion engine, which deteriorates the combustion state and is practically disadvantageous. There is inconvenience.

Further, when the throttle valve is fully opened, the pressure in the crankcase rises and the intake pipe pressure drops, that is, the intake pipe negative pressure weakens. The blow-by gas flows out from the breather hose upstream of the valve, the wall surface near the throttle valve is contaminated, and the sensing port and the like are clogged.

Further, during deceleration, the intake pipe pressure rises, that is, the intake pipe negative pressure becomes strong and a large amount of blow-by gas is sent to the combustion chamber of the internal combustion engine. However, the blow-by gas is sent more than necessary. If the oil is supplied, there is a disadvantage that the oil consumption increases, the cost increases, and it is economically disadvantageous.

[0015]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a crankcase which is connected to an intake passage on the upstream side of a throttle valve by a first connecting passage and a throttle by a second connecting passage. In an internal combustion engine that is provided in communication with an intake passage on the downstream side of the valve and has a PCV valve in the middle of the second communication passage, a solenoid valve is provided instead of the PCV valve to detect the pressure in the crankcase. Is provided
The detection signal from the pressure sensor and the detection signals of the intake pipe pressure in the intake passage and the engine speed are input, and the open state of the solenoid valve is feedback-controlled by a duty value so as to bring the inside of the crankcase into a negative pressure state. It is characterized in that a control means for controlling is provided.

The crankcase is provided so as to communicate with the intake passage on the upstream side of the throttle valve by the first communication passage, and is provided so as to communicate with the intake passage on the downstream side of the throttle valve by the second communication passage. In the internal combustion engine in which the PCV valve is provided, a solenoid valve is provided instead of the PCV valve, a pressure sensor for detecting the pressure in the crankcase is provided, and an opening / closing valve is provided in the middle of the first communication passage. And the detection signal of the intake pipe pressure in the intake passage and the engine speed are input to feedback control the open state of the solenoid valve by a duty value so as to bring the inside of the crankcase into a negative pressure state. Provided with a control means for closing the open / close valve when the valve is fully opened It is characterized in.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION With the above structure, the control means controls the inside of the crankcase to a negative pressure state,
The blow-by gas flow rate can be reduced to the required minimum to improve the combustion state, and at the time of deceleration, the open state of the solenoid valve is feedback-controlled by the control means to reliably control the blow-by gas flow rate during deceleration and reduce the oil consumption. , The cost is low.

Further, when the throttle valve is fully opened, for example, when the pressure at the intake passage side end of the first communication passage and the pressure at the intake passage side end of the second communication passage become substantially equal, the control means opens and closes. There is no fear that the valve will be closed and the throttle valve and the vicinity of the throttle valve will be contaminated by blow-by gas, and the usability is kept good.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 and 2 show a first embodiment of the present invention. In FIG. 1, 2 is an internal combustion engine, 4 is an intake passage, 6 is a throttle valve, and 8 is a crankcase formed in the lower part of the internal combustion engine 2.

The internal combustion engine 2 has an internal space 10. The internal space 10 is a first space portion 12 that is a separator chamber that accommodates a separator (not shown) above the internal combustion engine 2, and a second space portion that is a crank chamber that is formed inside the crankcase 8 below the internal combustion engine 2. 14 and.

The second space portion 1 of the crankcase 8
4 and the intake passage 4 upstream of the throttle valve 6 are provided with a first communication passage 16 and a second space portion 14 of the crankcase 8 is connected to the intake passage 4 downstream of the throttle valve 6. A communication passage 18 is provided.

The first communication passage 16 has a first passage 22 formed in a breather hose 20 connecting the intake passage 4 upstream of the throttle valve 6 and the first space portion 12, and the first space portion 12. And a second passage (not shown) formed inside the internal combustion engine 2 so as to communicate the second space portion 14 with the second space portion 14.

The second communication passage 18 includes a third passage 26 formed in a connecting member 24 connecting the intake passage 4 on the downstream side of the throttle valve 6 and the first space portion 12, and the first space portion. 12 and a second space portion 14 and a fourth passage (not shown) formed inside the internal combustion engine 2 so as to communicate with each other.

A solenoid valve 28 is provided in the middle of the second communication passage 16, that is, in the first passage 22, and a pressure sensor 30 for detecting the pressure in the crankcase 8 is provided.
To input the detection signal from the pressure sensor 30 and the detection signal of the intake pipe pressure Pb of the intake passage 4 and the engine speed Ne from a rotation speed sensor (not shown) to bring the inside of the crankcase 8 into a negative pressure state. A control means 32 for feedback-controlling the open state of the solenoid valve 28 according to a duty value is provided.

More specifically, the control means 32 searches the duty value in the map consisting of the engine speed Ne and the intake pipe pressure Pb to control the blow-by gas flow rate during the normal control. When the inside of the crankcase 8 is no longer under negative pressure, feedback control is performed,
The value of the map composed of the engine speed Ne and the intake pipe pressure Pb is updated.

Further, the control means 32 inputs the pressure sensor 30 for detecting the pressure in the crankcase 8 and the detection signals of the intake pipe pressure Pb of the intake passage 4 and the engine speed Ne, and the conventional means. The open state of the solenoid valve 28 arranged in place of the PCV valve is feedback-controlled by the duty value.

Further, the control means 32 controls the open state of the solenoid valve 28 so as to bring the inside of the crankcase 8 into a negative pressure state by feedback control. The duty value during this feedback control is shown in FIG. As shown in, the learning value is stored in the map composed of the engine speed Ne and the intake pipe pressure Pb.

Next, the operation will be described.

At the time of normal control, the control means 32 searches the duty value in the map consisting of the engine speed Ne and the intake pipe pressure Pb to control the blow-by gas flow rate.

When the inside of the crankcase 8 is no longer under negative pressure, the control means 32 carries out feedback control, and the engine speed Ne and the intake pipe pressure P.
Update the value of the map consisting of b and b.

That is, the control means 32 inputs the pressure sensor 30 for detecting the pressure in the crankcase 8 and the detection signals of the intake pipe pressure Pb of the intake passage 4 and the engine speed Ne, and The open state of the solenoid valve 28 is feedback-controlled by the duty value so as to bring the inside of the crankcase 8 into a negative pressure state.

Further, the control means 32 stores the duty value at the time of the feedback control as a learning value in the map composed of the engine speed Ne and the intake pipe pressure Pb.

Further, during deceleration, the open state of the solenoid valve 28 is feedback-controlled by the duty value by the control means 32.

As a result, the control means 32 can control the inside of the crankcase 8 to a negative pressure state, the blow-by gas flow rate can be minimized, and the combustion state can be improved, which is practically advantageous.

Further, since the open state of the solenoid valve 28 can be feedback-controlled by the control means 32 at the time of deceleration, the flow rate of blow-by gas at the time of deceleration can be surely performed and the oil consumption can be reduced.
The cost can be reduced, which is economically advantageous.

FIGS. 3 and 4 show a second embodiment of the present invention. In the second embodiment, portions that perform the same functions as those in the first embodiment will be described with the same reference numerals.

A feature of the second embodiment is that an opening / closing valve 42 is arranged in the middle of the first passage 22 forming the first communication passage 16, and the opening / closing valve 42 is closed when the throttle valve 6 is fully opened. This is in the point that the control means 44 is provided.

That is, a solenoid valve 28 is provided in place of the PCV valve, and a pressure sensor (not shown) for detecting the pressure in the crankcase (not shown).
Is provided in the middle of the first communication passage 16, that is, the first communication passage 1
An opening / closing valve 42 including an ON / OFF valve is provided in the middle of the first passage 22 of 6.

Then, the detection signal from the pressure sensor and the detection signals of the intake pipe pressure Pb in the intake passage 4 and the engine speed Ne are input to the control means 44 to bring the inside of the crankcase into a negative pressure state. Therefore, the solenoid valve 2
The open state of No. 8 is feedback-controlled by the duty value, and the opening / closing valve 42 is closed when the throttle valve 6 is fully opened.

At this time, whether or not the throttle valve 6 is fully opened is determined by the intake pipe pressure P as shown in FIG.
b, the engine speed Ne, and a constant in the table. Further, the maximum flow rate of the solenoid valve 28 is increased if necessary.

Then, the control means 44 can control the inside of the crankcase 8 so as to bring the inside of the crankcase into a negative pressure state, and the blowby gas flow rate becomes the minimum necessary and the combustion state as in the first embodiment. Can be improved, which is practically advantageous.

Further, since the open state of the solenoid valve 28 can be feedback-controlled by the control means 44 at the time of deceleration, as in the first embodiment,
The flow rate of blow-by gas during deceleration can be reliably controlled, the oil consumption can be reduced, the cost can be reduced, and it is economically advantageous.

Further, when the throttle valve 6 is fully opened, for example, the end of the first communication passage 16 on the intake passage 4 side and the end of the second communication passage 18 on the intake passage 4 side of the third passage 26 are connected. When the pressure becomes almost equal, the control means 44 closes the open / close valve 42, so that there is no fear that the throttle valve 6 and the vicinity of the throttle valve 6 will be contaminated by the blow-by gas, and the usability is kept good. obtain.

[0045]

As described above in detail, according to the present invention, the crankcase is provided so as to communicate with the intake passage upstream of the throttle valve by the first communication passage and the second passage.
In an internal combustion engine in which a communication passage is connected to the intake passage on the downstream side of the throttle valve and a PCV valve is provided in the middle of the second communication passage, a solenoid valve is provided instead of the PCV valve to detect the pressure in the crankcase. A sensor is provided, and the detection signal from the pressure sensor, the intake pipe pressure in the intake passage, and the detection signal of the engine speed are input, and the open state of the solenoid valve is fed back by the duty value in order to make the inside of the crankcase a negative pressure state. Since the control means for controlling is provided, it can be controlled by the control means so as to bring the inside of the crankcase into a negative pressure state.
The blow-by gas flow rate becomes the necessary minimum, the combustion state can be improved, and it is practically advantageous. Further, at the time of deceleration, the open state of the solenoid valve can be feedback-controlled by the control means, so that the flow rate of blow-by gas at the time of deceleration can be surely performed, the oil consumption can be reduced, and the cost can be reduced. Economically advantageous.

Further, the crankcase is provided so as to communicate with the intake passage on the upstream side of the throttle valve by the first communication passage, and is provided so as to communicate with the intake passage on the downstream side of the throttle valve by the second communication passage, and in the middle of the second communication passage. PC
In an internal combustion engine provided with a V valve, a solenoid valve is provided instead of the PCV valve, a pressure sensor for detecting the pressure in the crankcase is provided, and an opening / closing valve is provided in the middle of the first communication passage to detect a detection signal from the pressure sensor. The detection signal of the intake pipe pressure in the intake passage and the engine speed is input, and the open state of the solenoid valve is feedback-controlled by the duty value to keep the inside of the crankcase in a negative pressure state, and the open / close valve is closed when the throttle valve is fully opened. Since the control means for controlling the crankcase is provided, the control means can control the inside of the crankcase to be in a negative pressure state, and the blowby gas flow rate becomes the minimum necessary and the combustion state is improved, as in the first embodiment. Yes,
It is practically advantageous. Further, at the time of deceleration, the open state of the solenoid valve can be feedback-controlled by the control means, so that the flow rate of blow-by gas at the time of deceleration can be surely performed, the oil consumption can be reduced, and the cost can be reduced. Economically advantageous. Further, when the throttle valve is fully opened, for example, when the pressure at the intake passage side end of the first communication passage becomes substantially equal to the pressure at the intake passage side end of the second communication passage, the opening / closing valve is closed by the control means. By doing so, there is no fear that the throttle valve and the vicinity of the throttle valve will be contaminated by the blow-by gas, and the usability can be favorably maintained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a blow-by gas control device for an internal combustion engine showing a first embodiment of the present invention.

FIG. 2 is a map showing the relationship between engine speed Ne and intake pipe pressure Pb.

FIG. 3 is a schematic configuration diagram of a blow-by gas control device for an internal combustion engine showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between an engine speed Ne and an intake pipe pressure Pb.

FIG. 5 is a schematic configuration diagram of a blow-by gas control device for an internal combustion engine showing a conventional technique of the present invention.

FIG. 6 is a schematic enlarged sectional view of a PCV valve.

FIG. 7 is a diagram showing a flow rate characteristic of a PCV valve.

[Explanation of symbols]

 2 Internal Combustion Engine 4 Intake Passage 6 Throttle Valve 8 Crankcase 10 Internal Space 12 1st Space Part 14 2nd Space Part 16 1st Communication Passage 18 2nd Communication Passage 20 Breather Hose 22 1st Passage 24 Connection Member 26 3rd Passage 28 Solenoid valve 30 Pressure sensor 32 Control means

Claims (2)

[Claims] 1. A crankcase is provided so as to communicate with an intake passage upstream of a throttle valve by a first communication passage, and is provided so as to communicate with an intake passage downstream of a throttle valve by a second communication passage, in the middle of the second communication passage. To PC
In an internal combustion engine provided with a V valve, a solenoid valve is provided instead of the PCV valve, a pressure sensor for detecting the pressure in the crankcase is provided, and a detection signal from the pressure sensor and an intake pipe pressure in the intake passage are provided. Blow-by gas for an internal combustion engine, characterized in that a control means is provided for inputting a detection signal of an engine speed and a feedback value for the open state of the solenoid valve so as to bring the inside of the crankcase into a negative pressure state. Control device. 2. A crankcase is provided so as to communicate with an intake passage upstream of a throttle valve by a first communication passage, and is provided so as to communicate with an intake passage downstream of a throttle valve by a second communication passage. To PC
In an internal combustion engine provided with a V valve, a solenoid valve is provided in place of the PCV valve, a pressure sensor for detecting the pressure in the crankcase is provided, and an opening / closing valve is provided in the middle of the first communication passage. The detection signal and the detection signals of the intake pipe pressure in the intake passage and the engine speed are input, and the open state of the solenoid valve is feedback-controlled by a duty value so that the inside of the crankcase is in a negative pressure state. 2. A blow-by gas control device for an internal combustion engine, comprising: a control means for closing an opening / closing valve when fully opened.