JPS587819B2 - Mixture atomization accelerator for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention promotes atomization of the air-fuel mixture in a double-structured pipe downstream of the carburetor using the calorific value of exhaust gas during exhaust gas recirculation under low load, or so-called EGR, thereby reducing combustion fluctuations during EGR. Furthermore, during non-EGR idle and medium load, exhaust gas is introduced into a separate chamber of the double pipe to promote mixture atomization and enable lean combustion, and at high load, exhaust gas heating is not performed to improve intake efficiency. The aim is to improve output by improving

There have been many examples in the past in which exhaust gas heating is performed to promote atomization of air-fuel mixture.

For example, a riser plate (SUS or the like) is provided at the intake manifold collection part to heat the exhaust gas by heating the intake air by exhaust gas, and heats the exhaust gas mainly during idle.

Exhaust gas heating using EGR gas has also been proposed.

The disadvantage of the former is that the degree of exhaust gas heating is controlled by changing the flow of exhaust gas using a valve depending on the operating conditions, but since strong heating is performed even under high load, the suction effect decreases, causing a decrease in output.

Furthermore, although the latter is extremely effective during EGR, it has drawbacks such as being unable to promote atomization of the air-fuel mixture during non-EGR idling and medium load.

Therefore, the present invention solves this conventional drawback, that is, when EGR and non-EG.
This is intended to simultaneously promote atomization of the air-fuel mixture and improve output during R, or in the entire range of idling, low load, medium load, and high load.

In other words, the key point of the present invention is to improve the atomization performance by heating the exhaust gas during idle, low load, and medium load conditions.

Also, regarding the presence or absence of EGR, during EGR, exhaust gas is heated and the exhaust gas is used as EGR gas, and during non-EGR idle and medium load, only exhaust heating is performed, and exhaust heating is stopped during high load. It's about doing.

In order to achieve the present invention, a part that performs heat exchange (transferring exhaust heat to the air-fuel mixture) by exhaust heating is provided downstream of the carburetor throttle port and upstream of the intake manifold gathering part, and the structure of this part is adjusted to have a thermal conductivity. It is made of a double tube made of high quality material (such as steel alloy), and the inner and outer tubes are connected to the top and bottom.
Divided into a chamber, exhaust gas is introduced into one side, and the liquid fuel part that travels along the wall through this inner tube is heated and atomized, and then released from this chamber, branched into a reflux system path and a discharge system path, and selectively switched. During EGR, exhaust gas is passed through the recirculation system through the electromagnetic valve as a switching device, and after being controlled by the EGR control valve, it is guided again to the other chamber of the double pipe, and from this chamber it is ejected into the air-fuel mixture in the intake manifold. .

In addition, during non-EGR, the solenoid valve guides the exhaust gas to the discharge path, but during idle and medium load, the exhaust gas is guided to one chamber of the double pipe and heated through the inner pipe wall. A solenoid valve causes it to flow out into the release line.

However, under high load conditions, the intake efficiency decreases due to exhaust heat, leading to a decrease in output, so the solenoid valve is operated to connect the EGR system, but the EGR control valve located downstream is closed, so the exhaust gas does not flow into the intake system, and therefore there is no exhaust outlet and the flow stops, reducing the amount of heat exchange and making it possible to stop exhaust heating.

Furthermore, the kinetic force that creates the exhaust gas flow when performing exhaust gas heating is the negative pressure in the intake manifold during EGR, and at idle and medium load during non-EGR, for example, the kinetic force that creates the exhaust gas flow is intermittently applied to each exhaust port. It is possible to utilize the negative pressure of the pulsating exhaust force generated by the exhaust inertia effect.

In this case, EAI (secondary air introduction system), which is one of the exhaust gas purification devices, is applied, and a reed valve as a one-way valve is provided in the middle.

Another example may be an exhaust system provided independently of the main exhaust after-treatment system when the exhaust system becomes a discharge system using a differential pressure between exhaust pressure and atmospheric pressure, that is, a solenoid valve.

The embodiments shown in the accompanying drawings will be described below.

In each figure, 1 is a carburetor, 2 is a throttle valve, 3 is a throttle port, 4 is an insulation rake, 5 is an intake manifold, 5a is a water jacket part, 5b is a part of a riser, 5C is an intake manifold gathering part, 6 is a Mixture atomization accelerator, 6a is an inner port, 6b is an outer port, 6c is a heating space by exhaust gas, 6d is a partition plate, 6e is an EGR gas space, 6f is an EGR gas jetting part (turbulence generating part), 6g
is an exhaust gas wraparound prevention plate, 7 is an exhaust gas heating introduction hole, and 8 is an exhaust gas heating introduction hole.
1 is an exhaust gas heating discharge hole, 9 is an EGR gas introduction hole, 10 is an exhaust gas passage from an exhaust pipe, 11 is a solenoid valve, 11a is a three-way valve, 12 is an exhaust discharge pipe, 13 is an EGR control valve, 14 is an EG
R control mechanism, 16 indicates an EGR gas passage, and in Figures 4 and below, 2a is a primary throttle valve, 2b is a secondary throttle valve, 3a is a primary throttle port, and 3b is a 2
Next throttle port, 15 is the head, 17 is the reed valve, 18 is the exhaust gas injection pipe, 19 is the exhaust gas gallery, 20 is the exhaust manifold, 21 is the front tube, 22 is the catalytic converter, 22a is the heating exhaust gas A catalytic converter, 23 a muffler, and 23a a muffler for heating exhaust gas.

Embodiments of the present invention will be explained in order from FIG. 1 to FIG. 7.

FIG. 1 shows a gathering part 5 of the intake manifold 5 downstream of the carburetor.
A mixture atomization accelerator 6 is provided between the upstream and the exhaust gas introduced from the exhaust gas passage 10 is
After entering the upper heating space 6C and heating the liquid fuel flowing through the wall surface in the mixture through the inner port 6a and atomizing it, it exits from the discharge hole 8 and is heated by the three-way valve 11a of the solenoid valve 11 during EGR. It passes through the EGR gas passage 16, enters the space 6e of the mixture atomization promoting device 6 under quantitative control by the EGR control valve 13, heats the inner port 6a again, and then becomes a turbulent flow from the ejection part 6f. It mixes with the air-fuel mixture and enters the intake manifold.

Also, even during high load during non-EGR, the exhaust gas passage is connected to solenoid valve 1.
1, the discharge hole 8 and the EGR gas passage 16 communicate with each other, but at this time, the passage 16 and the introduction hole 9 are blocked by the EGR control valve 13, so that the exhaust gas does not flow as a whole, and therefore, exhaust gas heating is not performed. do not have.

In addition, during non-EGR idle and medium load, the exhaust gas passage 10, the introduction hole 7, the heating space 6c, the discharge hole 8,
Exhaust gas flows into the exhaust exhaust pipe 12 and EGR of the engine is not performed.

In this figure, it is assumed that the EGR control mechanism 14 that controls EGR includes various types.

Further, the electromagnetic valve 11 is operated by detecting the load range of the operating conditions, for example, by a rotary switch or the like based on the throttle angle of the carburetor.

FIG. 2 shows an example of a configuration in which the EGR gas ejection holes 6f in FIG. 1 are replaced with circumferential holes.

In contrast to FIG. 1 and FIG. 2, in which EGR gas is ejected from the lower part of the mixture atomization accelerator 6, FIG.
This figure shows one having the same configuration as the R introduction hole 9.

Figures 4 and 5 show a mixture atomization accelerator 6 installed downstream of the primary side of a single-port carburetor and a dual-port carburetor as shown in Figures 1, 2, and 3. 4 is similar to FIGS. 1 and 2, and 5 is similar to FIGS. 1 and 2. The figure shows something similar to FIG.

FIG. 6 shows the overall configuration of the actual machine. After the exhaust gas is heated by the operation of the solenoid valve 11, it is led to the exhaust discharge pipe 12, and the timing is set by the reed valve 17. A case is shown in which the exhaust gas is returned to the exhaust manifold 20 from each exhaust gas injection pipe 18 provided in the exhaust gas gallery 19 using negative pressure due to the exhaust inertia effect of the exhaust port.

FIG. 7 also shows a case where exhaust gas is purified by an independent exhaust system catalytic converter 22a and a muffler 23a from the exhaust pipe 12 and then released into the atmosphere.

The effects obtained by the present invention are listed below.

(1) Since atomization is promoted by exhaust gas heating during non-EGR idle and medium load, even if the air-fuel mixture is diluted, distribution is good, fuel efficiency is low, and fluctuations in combustion can be suppressed.

(2) At high loads during non-EGR operation, exhaust gas heating is not performed due to the combination of the EGR system, the valve that controls the discharge system, and the EGR control valve, so the output can be improved without reducing suction efficiency.

(3) Exhaust heating is utilized to the maximum at low loads during EGR, suppressing the deterioration of combustion fluctuations and increase in HC that are characteristic of EGR, and achieving high EGR with a lean mixture, resulting in after-treatment It is also possible to reduce the capacity of the oxidation catalyst, which is an exhaust purification device.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the main part of an embodiment of the present invention, and FIG.
It is a longitudinal cross-sectional view of a partially modified example of the figure. 3 to 5 are longitudinal cross-sectional views of other embodiments of the present invention, and FIGS. 6 and 7 are diagrams each illustrating an example of the overall configuration of an actual machine to which the present invention is applied. 2...Throttle valve, 5c...Intake manifold collecting section, 6...Mixture atomization accelerator, 6c...Heating space by exhaust gas, 6d・・・
...Partition plate, 6e...EGR gas space, 6
f...EGR gas ejection part, 9...EG
R gas introduction hole, 10...Exhaust gas passage from exhaust pipe, 11...Solenoid valve, 11a...3
Direction valve, 12...Exhaust discharge pipe, 13...
EGR control valve, 14...EGR control mechanism.

Claims (1)

[Scope of Claims] 1. A cylindrical double pipe for heating is formed in the intake passage downstream of the carburetor throttle valve and upstream of the intake manifold gathering part, and a cylindrical double pipe is formed in the gap between the double pipes to introduce exhaust gas. room and
a discharge system that communicates the chamber with the atmosphere; a reflux system that communicates the chamber with the intake passage; and a control valve that is interposed in the reflux system and shuts off the reflux system during high loads when exhaust gas is not recirculated. An internal combustion engine characterized in that it is provided with a switching device which shuts off the discharge line when exhaust gas is recirculated, opens the passage when the exhaust gas is not recirculated during idle and low to medium load, and shuts it off when the exhaust gas is not recirculated during high load. Mixture Atomization Promoting Device 2 The mixture atomization promoting device for an internal combustion engine according to claim 1, wherein the discharge path is a communication path communicating with the engine exhaust passage via a one-way valve. 3. The air-fuel mixture atomization promoting device for an internal combustion engine according to claim 1, wherein the discharge path is a communication path that is separated from the engine exhaust path and communicates with the atmosphere via an exhaust purification device.