JPS5958143A - Control device for evaporated fuel in internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance the operationablity and exhaust gas characteristics of an engine, by allowing evaporated fuel trapped in a canister to flow into an engine exhaust system upstream of an exhaust purifying device so that the capability of disposal is maintained and an affection to the air-fuel ratio of the engine upon combustion thereof is eliminated. CONSTITUTION:Evaporated fuel generated in a fuel tank 1 is transferred to a storage chamber 4 in a canister 3 through a passage 6 and trapped therein by being absorbed. When a pressure in the vicinity of a throttle valve 7 in an intake-air passage within a range of low or intermediate engine load becomes high vacuum pressure, a purge control valve 10 opens to establish the communication of an evaporated fuel feed passage g'. Thereby, pressure in an exhaust passage 14 is applied to the storage chamber 4 through a check valve 15 when it become negative pressure due to exhaust gas pulsation, so that the absorbed evaporated fuel is introduced into the exhaust passage 14 through the feed passage 9' together with the atmospheric air which has passed through a filter material 12. Further, the evaporated fuel is transferred to an exhaust purifying device 13 together with high temperature exhaust gas, and is burnt by the atmospheric air which is fed together with the evaporated fuel. Thereby, the operationability and exhaust gas characteristics of the engine is remarkably enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a steam fuel control system for an internal combustion engine.

In general, in J3 automobile internal combustion engines, the above-mentioned measures are taken to prevent the release of evaporative gas (mainly harmful I-I C components) generated in the fuel tank etc. as part of the exhaust gas countermeasures. It is equipped with an FC evaporative fuel control device to allow evaporated gas to flow through several ports for combustion processing.

As a conventional evaporative fuel control device, there is, for example, the one shown in Fig. 1 (Japanese Unexamined Patent Publication No. 1983-775/15).
.

This is due to the activation of the air chamber 2 of the fuel tank 1, which is the source of the fuel evaporation valve, and the air chamber 3 of the fuel tank 1! A storage chamber 4 filled with an adsorbent such as 1 charcoal is connected to a storage chamber 4 through a passage 6 equipped with a lever lever 5 in the middle. Fuel is sent to the canister 3, where it is temporarily adsorbed and stored.

In addition, the storage chamber 4 of the canister 3 and the intake passage (intake manifold) ε3 downstream of the throttle valve 7 are connected by the evaporative combustion 1 supply passage 9, and the supply passage is connected to the intake passage downstream of the throttle valve 7. At the portion t1 where the negative pressure in the intake passage 8 is strong (4), the valve is opened during load operation.7) The conduction is controlled by the flam type purge control valve 10.

First, the purge control valve 10 has its pressure chamber '1
Throttle valve 7 (s
In response to (V C negative pressure), when the 0 pressure in the IF force chamber '10Δ increases in the engine's low and medium r'' JJ range 3, the tie 17 Nora l\1013 becomes The valve body 10C, which is integrated with the tie A7 flamm 10B, moves upward in the middle, and the valve body 10C, which is integrated with the tie A7 flamm 10B, connects to the valve LI section 9Δ of the vaporized fuel supply passage 9 mentioned above.
C. The supply passage 9 is opened and the supply passage 9 is made conductive.

Therefore, in the low and medium load range of the engine (13C), valve 7 is controlled to close, and the intake passage is depleted.
When the monthly r power becomes high ft IF k-, 1- mentioned J
, when the sea urchin purge control valve 10 opens, the evaporated fuel supply passage 9
is conductive.

In addition, zero suction pressure downstream of the throttle valve 7 acts on the storage chamber 4 of the cylinder 3 through the supply passage 9, and this suction negative pressure causes the adsorbed evaporated fuel in the storage chamber 4 to be transferred to the storage chamber 4. After passing through the filter medium 12 of No. 3, the air is introduced into the intake passage 8 through the supply passage 9, and is then supplied to each combustion chamber of the interlayer wood body 13 for combustion treatment.

In this way, the evaporated fuel is burnt as appropriate depending on the operating conditions, so there are no problems such as pollution caused by the evaporated fuel being released during operation.

However, such conventional fuel z1 evaporation control
In the device, the above-mentioned evaporated fuel supply passage 9 is communicated with the intake passage 8 downstream of the throttle valve 7, and the evaporated fuel stored in the =1t nister 3 is discharged from the new evaporated fuel introduced into the kiki nister 33. Since the structure was such that the fuel vapor is returned to the engine intake passage E3 along with air, the air-fuel ratio of the mixture in the engine combustion chamber will vary greatly depending on the degree of adsorption of evaporated fuel to the fuel tank 3. As a result, there was a problem in that the interlayer operation and 171 I11 performance were severely deteriorated.

This invention was made by paying attention to such conventional problems, and it is possible to eliminate
The structure is such that 31 Kanayama or a part of the evaporated fuel is returned to the engine exhaust system using catalysts, etc., and the evaporated fuel processing function remains the same as before.
In order to eliminate the effect on the air-fuel ratio,
The purpose is to solve the problems mentioned above.

Next, embodiments of this invention will be explained based on the drawings.

As shown in FIG.
1st air passage 1/l is the comparison valve eye of intake passage ε3; evaporative fuel 11 supply passage whose conduction is controlled by purge control valve j''10 which responds to G41t (V to M pressure) near 1 9′
When the evaporated fuel supply passage 9 is opened during partially zero load operation of the engine, the internal pressure of the air passage 14 reaches negative pressure by 4f due to the pulsation of the 111 air flowing in the bleed air passage 1/I. , 11. The adsorbed fuel in Costa 3 passes through the supply passage 9 in 1) C, and the above-mentioned IJI air purification equipment 13 is introduced into the 111 air passage 1/I. There is.

Preferably, Gt is placed in the middle of the supply passage 9 of the evaporation combustion mixture 1, and when the supply passage 9' is conductive (J due to exhaust pulsation), when the internal pressure of the bleed passage 11 becomes positive, the exhaust gas flows into the kitonister 3.
A check valve 15 is installed to prevent backflow to the side. In other words, only when the internal pressure of the exhaust passage 14 becomes negative, the reball valve element 15a moves toward the exhaust passage 14 against the force of the valve spring 15b, and the valve between , to secure a flow path in the direction in which the evaporated fuel flows from the fuel vaporizer 3 to the exhaust passage 14 side.

The rest of the structure is the same as in FIG. 1, so the same members as in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

Because of this configuration, evaporative fuel generated in the fuel tank 1 during engine operation (stopping, etc.) is passed through the J passage 6 to the reservoir chamber 4 of the Kitnister 3, where it is temporarily stored. It is adsorbed and stored.

After this, when the engine is operated and the pressure near the intake passage 8 throttle or fin becomes high negative pressure when the engine is in a low to medium load range where the throttle valve 7 is controlled to close, purge as described above. The control valve 10 is opened and the vaporized light/fuel diagonal supply passage 9 is opened.

In addition, when the internal pressure of the air passage 4 is equal to the 1-1 air pulsation, this negative F is the check valve 1;
F[river] is transferred to the storage chamber 4 of 2 stars 3 through 4 channels, and the (1
Due to stupidity, the adsorbed evaporated fuel in the C storage chamber 4 becomes -Y+・nista 1, II vent ii'81/I internal pressure becomes i [pressure t
By closing the check valve 1F at time s, the evaporated fuel supply passage 1]' becomes a! The reflux of evaporative fuel +1 to the JJI gas passage 14, which is done at 4 places, is the same as k, and the 41+ gas waste does not flow back to the canister 3 side.

-Thus, the seafood combustion 1 (IIG component) recirculated to the exhaust passage 1/I is sent together with high-temperature exhaust gas to the exhaust purification device 133 installed in the exhaust passage 14, where it is At the same time, the evaporative combustion is effectively combusted (oxidized) in the atmosphere that is returned to the atmosphere.Because it is treated in this way, the evaporative combustion is released as in the conventional case. is defended.

In addition, unlike in the conventional example, in this embodiment C, the entire amount of evaporated fuel is not returned to the intake system, so the air-fuel ratio becomes extremely enriched during engine combustion and the accompanying operation 1. This prevents the exhaust system from getting burnt out due to the deterioration of the engine and the occurrence of misfires.

In addition, in the case of this embodiment, compared to the conventional example in which the evaporated fuel flows all the way to the intake system at high speed, and there is a loss of 10 heat when C is burned in the combustion chamber, the total heat I-energy in the JJI gas system is much more effective. Since it is used, there is also the advantage that the rapid deterioration of the exhaust purification device 13 such as an oxidation catalyst is accelerated by 1lfl.

Next, FIGS. 33 and 4 show other embodiments of the present invention.

FIG. 33 shows the steamed paddy supply passage 9 upstream of the check valve 15.
The thermo-light fuel supply passage 9, which is connected to the intake passage ε3 downstream of the throttle valve 7, is branched from [J, and the engine cooling 74 is connected to this branch.
1. A three-way solenoid valve 17 is provided that responds to a signal from a water temperature controller 16 that detects water wetting, and this three-way solenoid valve 17 closes the air system between the kitonista 3 side and the 1llr air system when the engine is cold and the water humidity is below a predetermined temperature. 6 is connected so that the intake system is connected to the canister 3 side during warm-up when the temperature exceeds the predetermined temperature.
The steam 5 selectively switches and controls the fuel supply passage 9.9. J
This is an example of ζ.

In the figure, 'IE3' is a relay for preventing switching operation of the above-mentioned solenoid valve 17 by the water temperature control 16.

According to this, when the engine is cold, the vaporized fuel will be returned to the JJI air passage 14 as shown in Fig. 2, and this will cause -C engine start ii! After j, etc. in C1-
A large amount of evaporated fuel stored in the Kitostar 33 for a long time when the 6F+ was left unattended.
The air is not refluxed to the intake system in a short period of time, and the same effect as shown in FIG. 2 can be obtained.

On the other hand, since the evaporated fuel is gradually recirculated in small amounts, there is no fear of extreme air-fuel ratio fluctuations, and the L/hs is also sufficiently high.
FII It! In the first flash, the entire amount of evaporated fuel will be flowed into the intake passage E3), and this will cause all the evaporated fuel to flow into the intake passage E3. It has the advantage that C can be used effectively as 1 channel - 1!.

]! /I diagram (, 11, evaporative combustion gas in Figure 33
Check the temperature inside the fuel tank 1 at the branch point 1J of the supply passage 90 (
"i" temperature switch 20, the solenoid coil 1 is activated only when the temperature inside the fuel tank 1 is below a predetermined temperature.
9A is energized and the internal blank 19[3 is J, which cuts off the supply passage 9. Otherwise, the energization to the solenoid coil 19△ is stopped and the internal blank 19B is energized.
Both supply passages 9 are brought into contact with the I-flange 19C.
), 9 communicate with the chitonister 3 side, in this example, an electromagnetic switching valve 19 is installed to switch and control each supply passage 9, 9.

Incidentally, reference numeral 21 in the figure is a relay for operating the electromagnetic switching valve 19 by the temperature switch 20. .

According to this, when the temperature inside the fuel tank 1 rises and exceeds the set humidity, 1W of fully combusted*+1 flows not only into the exhaust passage 14 but also into the intake passage 8, and this causes J For example, when a vehicle repeatedly runs in a hot region and the evaporation rate in the fuel tank 1 becomes more active, a large amount of evaporated fuel is returned only to the gas system and the exhaust purification device 1
To avoid significantly worsening the exhaust performance C1 by exceeding the processing capacity of 3, and to prevent the exhaust system from becoming abnormally humid and causing burnout or melting damage. , λ.

Of course, when the temperature is below the set temperature, the steam valve combustion gas is refluxed only to the 11 gas system, so that the same effect as shown in FIG. 2 can be obtained.
1. In the case of the octopus embodiment, both supply passages ≦).

When supplying the evaporative fuel 11 to the double 7j of Fg, the suction force (5
Since F, /l-(February force) is different, both supply passages9.
9) Interposing the passage (with a difference in ¥, l!Iζ comparison (Δlinois)
:stomach.

In addition, when supplying evaporated fuel to the IJ+ gas system in Example 1 below, if IJI'IT- is high and difficult to enter, use 11-up.1. It should be said that it is good to supply U-Ct) not more than 3°, as explained above. J, -) (J, j, re1.
L, All or part of the evaporated fuel is returned to the engine IJI gas system upstream of the exhaust gas purification device such as a catalyst.Since 4 to 6 gases have been formed, the evaporated fuel is 1'+ 17)I11 Combustion processing that returns to the gas system 2) - (previously passed as a popular way to prevent the release of hazardous evaporative fuel 1 min.) It is possible to eliminate the effect on the air-fuel ratio of fuel Ijtl combustion I+, 'J (13), which has the effect of further improving engine operation and exhaust performance.
Furthermore, there is also the advantage that warm-up of exhaust gas purification devices such as catalysts is accelerated.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a conventional example, Fig. 2 is a schematic diagram of an embodiment of the invention, and Figs. 3 and 4 show a second and third embodiment of the invention. composition . It is a diagram. 1...Mo*31 tank, 33...Kitnista, 13
...Exhaust purification charge, 1/I...Exhaust passage, 9,9'
...Evaporative fuel 11 supply passage, 15...Reverse IL valve, 8...
・Intake passage, 17... Three-way solenoid valve, 19... Solenoid switching valve, 16... Water (gll, ? series - 11 pieces... Temperature switch.

Claims (1)

[Scope of Claims] i, ffi) A tank that stores the evaporated fuel generated in a tank, etc., where all or part of the evaporated fuel stored in this canister is used for exhaust purification using a catalyst, etc. An evaporative fuel supply passage that supplies the IJI gas passage of the loaded fuel flow, and a reverse 1F valve that is interposed in this evaporative 5F fuel 11 supply passage and prevents the reverse flow of C exhaust scum from the 1-tonister side l\. 2.1-The light fuel supply passage communicates from the check valve flow to the throttle valve flow intake passage. The fuel 11 supply passage branches into the S branch point and supplies vaporized fuel to the bleed passage and intake passage either selectively or to both depending on the operating condition of the engine.
j Equipped with a valve device that switches the passages so that they can be supplied at the same timeC
I hope you are there! Features: 1. An internal combustion (evaporative fuel control system) according to claim 1.