JPS5821089B2 - Automotive jet-controlled combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in internal combustion engines, particularly internal combustion engines for automobiles.

In conventional internal combustion engines for automobiles, the efficiency of intake air into the combustion chamber is poor because it is throttled by the throttle valve, and the flow rate of the intake air flowing into the combustion chamber is low. bad.

Therefore, in general, the above deterioration in ignition and combustibility is solved by supplying a rich mixture with a good combustion chamber, that is, a mixture with a low air-fuel ratio. There are problems such as an increase in unburned gas HC and Co.

In recent years, it has been proposed to burn a mixture that is sufficiently leaner than the stoichiometric mixture ratio, especially with the aim of reducing harmful NOx in exhaust gas, and it has also been proposed to extract part of the exhaust gas from the engine exhaust system. It has also been proposed to mix the mixture into an air-fuel mixture and combust it, but in either case, the ignitability of the air-fuel mixture and the combustion chamber deteriorate, resulting in a disadvantage of deterioration of drivability and fuel efficiency.

Special Publication No. 47-24041 or Special Publication No. 47-43366
The prior art shown in the No. 1 sucks a rich mixture and air or a lean mixture into the cylinder through separate routes, prevents the two from mixing until the point of ignition, and immediately before ignition, the rich mixture is sucked into the cylinder around the spark plug. The air or lean mixture is guided away from the spark plug, ignites the rich mixture, improves ignition combustibility, and achieves a lean burn with an overall air-fuel ratio. However, this technique has the disadvantage that the device and control become complex in order to always achieve good stratification and lead a rich mixture to the vicinity of the spark plug, regardless of the operating state.

A main object of the present invention is to provide a jet-controlled combustion engine for an automobile that can improve fuel efficiency.

Another object of the present invention is to be able to stably burn a lean mixture that is difficult to operate stably in a normal engine;
As a result, it is an object of the present invention to provide a jet flow control combustion engine for automobiles in which harmful components in exhaust gas are reduced.

Still another object of the present invention is to be able to stably burn an air-fuel mixture containing a large amount of recirculated exhaust gas, which is difficult to operate stably in a normal engine, and as a result, the amount of N in the exhaust gas is reduced.
An object of the present invention is to provide a jet flow control engine for an automobile that can reduce Ox.

Another object of the present invention is to provide jet flow control for an automobile that can stably burn a lean mixture or a mixture containing a large amount of recirculated exhaust gas without causing inconveniences such as a large decrease in output, deterioration of drivability, and deterioration of fuel efficiency. The purpose is to provide a combustion engine.

Still another object of the present invention is to provide a jet flow control combustion engine for an automobile that can significantly reduce harmful gas components in exhaust gas and fuel consumption compared to conventional conventional engines, especially in idling and low-speed, low-load light-load operating regions. It is in.

Another object of the present invention is to provide a jet-controlled combustion engine for an automobile that effectively reduces unburned gas in exhaust gas in a catalytic converter without supplying secondary air to the exhaust passage.

The aspects of the present invention described above are such that the spark gap of the ignition plug is located inside the combustion chamber, which has an intake port through which the air-fuel mixture generated by the carburetor is supplied through the main intake passage, and an exhaust port through which exhaust gas is guided to the catalytic converter. At the same time,
An injection hole is provided near the spark gap and directed toward the vicinity of the spark gap. Air or a lean mixture is injected into the combustion chamber from the injection hole by the negative pressure generated in the combustion chamber during the intake stroke, and the carburetor injects air or a lean mixture from the injection hole during low-speed, low-load operation including at least idling. This is effectively achieved by a jet flow control combustion engine for automobiles in which the total air-fuel ratio of the intake air or lean mixture and the mixture taken in from the intake port is controlled within the range of stoichiometric air-fuel ratio or more and 17 or less.

The engine according to the present invention improves ignition combustibility by adding a simple sub-intake system that injects gas into the cylinder, and employs a combustion method that is completely different from the layered combustion described above. Especially during idling and light load operation, the throttle opening is small, so the throttling action of the throttle valve is slow, and the intake air velocity from the main intake passage is slow, resulting in a small amount of intake air and a high temperature inside the combustion chamber during the intake stroke. The high negative pressure causes air or lean mixture to be sucked in and powerfully injected into the combustion chamber from the injection hole as a high-velocity jet stream.This jet stream scavenges the burnt gas around the spark gap. In addition to improving ignition performance, it also generates strong swirl and turbulence within the combustion chamber, and these swirl and turbulence remain during the compression stroke, causing the mixture to flow in a vortex shape and aiding flame propagation after ignition. , the combustion rate increases and the lean burn limit is extended.

Therefore, especially during idling and light load operation, the overall air-fuel ratio of the air-fuel mixture taken in from the injection holes and intake ports is controlled within the range of 17 or higher than the stoichiometric air-fuel ratio, which may cause engine vibration or a decrease in output. In addition, the amount of unburned gas remaining in the exhaust gas discharged from the combustion chamber to the exhaust port is reduced, making it possible to reduce the capacity of the catalytic converter and reducing the amount of secondary air in the exhaust passage. The unburned gas is effectively reduced by the residual oxygen in the exhaust gas without supplying the unburned gas.

Furthermore, if an exhaust gas recirculation device is used in conjunction with the engine of the present invention, deterioration of ignitability and flame speed due to exhaust gas recirculation will be improved by the jet stream, so it will be easy to avoid setting the air-fuel ratio to a value close to the misfire limit. It becomes possible to reduce the amount of NOx generated.

As the opening of the throttle valve approaches full opening, the amount of inflow from the intake port, which is normally opened and closed by the main intake valve, increases, the inflow speed of air or lean mixture from the injection hole slows, and the swirl caused by the jet flow increases. The effect becomes less and closer to the conventional combustion mode.

According to the invention, therefore, within the entire operating range of the engine,
This provides an engine with low fuel consumption and clean exhaust gas without reducing output or deteriorating drivability.

Next, the present invention will be explained in detail with reference to an embodiment shown in FIGS. 1 to 3.

The outer shell of a main body 1 of a four-stroke multi-cylinder gasoline engine for automobiles is mainly composed of a cylinder block 2 and a cylinder head 3. An intake manifold 4 is fixed to one side of the cylinder head 3, and an exhaust manifold 5 is fixed to the other side. has been done.

A carburetor 6 is fixed to the upper part of the intake manifold 4, and an air cleaner 7 is attached to the upper part of the carburetor 6, and the air purified by the air cleaner 7 is sent to the carburetor 6.
The air is guided through a main intake passage 8 formed in the intake manifold 4 to an intake port 9 formed in the cylinder head 3.

A throttle valve 10 that opens and closes in conjunction with the operation of an accelerator pedal (not shown) is interposed in the carburetor 6 portion of the main intake passage 8, and the intake air is mainly supplied from the upstream side of the position where the throttle valve 10 is installed in the main intake passage 8. Sub-intake passage 1 where part is inhaled
1 is opened in the intake passage wall of the main intake passage 8.

A part of an exhaust gas recirculation passage 13 whose one end communicates with an exhaust port 12 formed in the cylinder head 3 is integrally formed in the intake manifold 4, and the other end of the passage 13 is connected to a main intake passage within the intake manifold 4. is communicated with.

Further, a cooling water passage 14 constituting a heat riser is provided at the lower part of the intake manifold 4, and a thermosensor 15 is attached to the passage 14.

Further, a control valve 16 for controlling the amount of recirculation is interposed in the middle of the exhaust gas recirculation passage 13, and the control valve 16 is controlled by an actuating device 17 that provides a desired opening depending on the operating state of the engine.

Specifically, the actuating device 17 is one that mechanically interlocks with the opening degree of the throttle valve 10, or one that operates in response to an intake vacuum generated at a specific position within the main intake passage 8 that is determined particularly in relation to the throttle valve 10. There are some that perform pneumatic control depending on the magnitude of the pressure.

The thermosensor 15 detects whether the engine is cold or overheated based on the engine cooling water temperature, and controls the exhaust gas recirculation amount control valve 16 or an ignition advance control device (not shown).

Furthermore, the exhaust manifold 5 that communicates with the exhaust port 12 of each cylinder is formed into an upper and lower two-part structure that is screwed into place by bolts 18, and the exhaust manifold 5 has a gathering part where the exhaust gas is connected, as shown by the arrow in FIG. A radial flow type catalyst layer 19 whose axis of flow is vertical is built in, and the lower part of the exhaust manifold 5 is connected to an exhaust pipe 20.

Next, referring to FIGS. 2 and 3, the internal structure of the main body 1 will be explained. A hemispherical baking chamber 24 is formed, and the intake port 9 and exhaust port 12 are opened at predetermined positions of the concave surface 23.

The ignition plug 25 is screwed into a through hole 26 formed in the hemispherical concave surface 23, and the spark gap 2T of the ignition plug 25 is located on or near the extended surface of the concave surface 23.

Further, a through hole 28 that opens adjacent to the spark gap 27 is bored in the concave surface 23, and a hollow cylindrical jet piece 30 is press-fitted into the through hole 28 from the combustion chamber 24 side, and from the opposite side. When the jet body 32 is fitted, the male screw part provided on the outer circumferential surface of the end of the jet body 32 and the female thread part provided on the inner circumferential surface of the end of the jet piece 30 are screwed together. It is fixed to the cylinder head 3 by sandwiching both lined surfaces 33 and 34.

A mushroom-shaped jet valve 35 is slidably fitted into the jet body 32, and the outer circumferential surface of the valve stem of the jet valve 35 and the inner circumferential surface of the jet body 32 are connected to the male threaded end of the jet body 32. A sub-intake passage 36 having an annular cross-sectional shape with a gap is formed, and the sub-intake passage 36 connects the inner circumferential surface of the through hole 28 and the outer circumference of the jet body 32 through a hole 37 bored in the jet body 32. It communicates with an auxiliary intake passage 38 formed in the gap between the cylinder head 2 and the cylinder head 2, and the passage 38 further communicates with an auxiliary intake passage 39 formed in the cylinder head 2, which in turn is connected to the auxiliary intake passage 11. .

The auxiliary intake passage 36 has a small volume injection chamber 4 that is limited by the inner surface of the jet piece 30 and the end face of the umbrella portion of the auxiliary intake valve 35.
0, and the opening is closed when the valve face of the sub-intake valve 35 comes into contact with the valve seat 41 formed at the tip of the jet body 32.

The part of the jet piece 30 exposed to the combustion chamber 24 is formed into a hollow shell shape, and an injection hole 42 that communicates the combustion chamber 24 and the injection chamber 40 is bored in this shell.
Reference numeral 2 is provided at a position close to the spark gap 27 of the ignition plug 25 and on a substantially extended surface of the concave surface, and is an air-fuel mixture sucked into the combustion chamber 24 from the intake port 9 in a direction near the gap 11. It is directed in the forward direction with respect to the swirl direction shown by arrow a in FIG.

In addition, in FIG. 2 and FIG. 3, the direction of injection from the injection hole 42 is indicated by an arrow x.

Intake valve 43 that opens and closes intake port 9 and the above-mentioned sub-intake valve 3
Reference numeral 5 designates mushroom valves both driven by the same rocker arm 44, which is fitted onto a rocker shaft 45 and swings in contact with a cam 47 provided on a camshaft 46 rotated by the engine. The arm portion on the side opposite to the abutting surface to the cam 47 is bifurcated into two parts, and adjustment screws 48 and 49 are screwed into each of the bifurcated parts.

The end surface of the adjusting screw 48 is still in contact with the upper end surface of the valve stem of the main intake valve 43, and the end surface of the adjusting screw 49 is in contact with the end surface of the valve stem of the sub-intake valve 35.

Note that 50 and 51 are valve springs, and 52 and 53 are retainers.

Further, the exhaust valve 54 that opens and closes the exhaust port 12 is opened and closed by the swinging of a rocker arm 56 fitted to a rocker shaft 55, and the rocker arm 56 swings as it comes into contact with a cam 57 provided on the camshaft 46. .

In addition, 58 is an adjustment screw, 59 is a valve spring, and 60 is a retainer.

According to the above configuration, when the intake valve 43 and the jet valve 35 open during the intake stroke, the air-fuel mixture generated in the carburetor 6 is mixed with the recirculated exhaust gas in the intake manifold 4 due to the negative pressure generated in the combustion chamber 24. After that, part of the intake air is drawn into the combustion chamber 24 from the intake port 9 while creating a swirl along the inner peripheral surface of the cylinder 21 as shown by the arrow a in FIG. is inhaled into the injection chamber 40 mainly through the main intake passage 8 upstream of the throttle valve 10 and the auxiliary intake passage 36 .

The air sucked into the injection chamber 40 is injected into the combustion chamber 24 through the injection hole 42 and scavenges the burned gas around the spark gap 27, as well as inside the hemispherical concave surface 23 of the cylinder head 3 and the cylinder 21. The swirl of the air-fuel mixture is strengthened while flowing down along the circumferential surface.

Therefore, the jet stream gives a strong swirl to the air-fuel mixture taken into the combustion chamber 24, mixes appropriately with the air-fuel mixture and dilutes the air-fuel mixture, and also scavenges the area around the spark gap 27 to ignite the air-fuel mixture. Improves flammability and flammability.

i Furthermore, in the latter half of the compression stroke, the spark gap 27
When ignited by
The injection chamber 40 is a small chamber, and strong turbulence is generated when the air-fuel mixture in the combustion chamber 24 flows into the injection chamber 40 during the compression stroke. The air-fuel mixture is rapidly combusted and becomes high temperature and pressure, and flame is vigorously injected into the combustion chamber 24 from the injection hole 42.
This jet also promotes the ongoing combustion within the combustion chamber 40.

By the way, the carburetor 6 has an injection hole 42 and an intake port 9.
The overall air-fuel ratio in the combustion chamber 24, which is generated by intake from both of In particular, during low-speed, low-load operation, including idling, the overall air-fuel ratio is controlled within the range of 17 or higher than the theoretical air-fuel ratio, and even in operating conditions other than the above, the operating condition is other than the operating condition at or near full output. In this case, the overall air-fuel ratio is controlled to be higher than the stoichiometric air-fuel ratio.

In Fig. 4, the solid line A indicates the full-open output line, the point B indicates the idle position, and the dashed line indicates the overall air-fuel ratio of 13,
15.17 is each constant air-fuel ratio line.

Further, the catalyst layer 1 built in the collecting part of the exhaust manifold 5
9 is a pellet-shaped activated alumina Al2O3 carrier; the surface of the carrier is impregnated with a noble metal oxidation catalyst such as Pd, which is formed by filling a heat-resistant cylindrical core with double pores; The catalyst capacity of the engine is set to 70% or less of the total displacement.

In other words, the overall air-fuel ratio is set to be higher than the stoichiometric air-fuel ratio in most of the operating range, and the combustion of the air-fuel mixture in the combustion chamber 24 is improved by the jet flow from the injection holes 42. The unburned gases HC and Co in the exhaust gas discharged into the exhaust manifold 5 are extremely reduced compared to those of conventional general engines, and the HC and Co in the catalyst layer 19 are
Only a small amount of CO is required to be purified, and therefore the catalyst capacity of the catalyst layer 19 can be reduced to 70% or less of the total displacement of the engine.

Note that when the amount of HC and CO discharged into the exhaust port 12 is reduced, the exhaust gas temperature decreases, making it difficult to maintain the catalyst layer 19 at a high temperature higher than the operating temperature.
By arranging the catalyst layer 19 in the exhaust manifold 5 near the combustion chamber 24 and using the above-mentioned catalyst with a low minimum reaction temperature of 250°C, the catalyst layer 19 has a sufficient purifying effect. In the example, since the overall air-fuel ratio is set to be higher than the stoichiometric air-fuel ratio in most of the operating range, residual air in the exhaust gas is As a result, unburned gas is sufficiently reduced, and there is no need to provide a special secondary air supply device.

Furthermore, in this embodiment, especially in the idling and light load operating regions where air-fuel mixture distribution performance and intake efficiency are poor, and combustibility is poor due to reasons such as low combustion chamber wall temperature,
The overall air-fuel ratio is controlled within the range of 17 or higher than the stoichiometric air-fuel ratio, and a powerful jet stream is generated within the range of 30% to 50% of the total intake air amount injected from the injection hole 42, resulting in combustion. Due to the improved performance, fuel efficiency is greatly improved.

Furthermore, during idling, in conventional engines, using a lean mixture, which is advantageous for exhaust gas purification, deteriorates combustion stability and makes it difficult to set the engine speed low, but in this example, the jet By improving combustion due to the flow, it becomes possible to set the engine speed to about 500 rpm, which is below 700 rpm, and as a result, fuel efficiency is further improved.

Incidentally, in this embodiment, the amount of exhaust gas recirculation is controlled by the actuating device 17 as shown in FIG. 5, and the amount of NOx generated is suppressed within a predetermined value by this exhaust gas recirculation.

In Fig. 5, the solid line A is the full-open output line, and the two-dot chain line for the exhaust gas recirculation amount is the exhaust gas recirculation rate (weight ratio) = □ When the intake fresh air amount x 100, the exhaust gas recirculation rate is 0.5°15. 2
The equal exhaust gas reflux rate lines at the 0 and 25 stages are shown.

Therefore, as is clear from FIGS. 4 and 5, in this example, a large amount of exhaust gas recirculation occurs despite the introduction of a lean air-fuel mixture in the low- and medium-load driving ranges that are frequently used in city driving. is possible.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG. 2 is a schematic diagram showing an embodiment of the present invention.
3 is a Z-Z arrow view in FIG. 2, FIG. 4 is an explanatory diagram of the air-fuel ratio characteristics in the above embodiment, and FIG. 5 is an exhaust gas recirculation amount in the above embodiment. It is an explanatory diagram of characteristics. 1: Internal combustion engine open body, 2 cylinder block, 3 cylinder head, 4: intake manifold, 5: exhaust manifold, 6: carburetor, 8: main intake passage, 9: intake port, 10
: Throttle valve, 11° 36, 38, 39: Sub-intake passage, 12: Exhaust port, 21: Cylinder, 23: Hemispherical concave surface, 24: Combustion chamber, 25: Spark plug, 27: Spark gap, 30 Nijet piece, 32 Nijet body, 35 Nijet valve, 37: Hole, 40: Injection chamber, 42: Injection hole, 43: Intake valve, 54: Exhaust valve.

Claims (1)

[Claims] 1. The spark gap of the ignition plug faces into a combustion chamber that has an intake port through which the air-fuel mixture generated by the carburetor is supplied through the main intake passage and an exhaust port that guides exhaust gas to the catalytic converter. At the same time, an injection hole is provided near the spark gap and directed toward the vicinity of the spark gap. Connected to the intake passage, air or a lean mixture is injected from the injection hole into the combustion chamber by negative pressure generated in the combustion chamber during the intake stroke, and the carburetor injects the injection at least during low-speed, low-load operation including idling. The total air-fuel ratio of the air or lean mixture taken in from the hole and the mixture taken in from the intake port is equal to or higher than the stoichiometric air-fuel ratio 1
A jet flow control combustion engine 32 for an automobile controlled within a range of 7 or less, the engine according to claim 1, wherein the injection amount from the injection hole is 30% of the total intake air amount during idling and very light load operation. ~50% automotive jet-controlled combustion engine. 3. A jet flow control combustion engine for an automobile according to claim 1, in which the catalyst capacity of the catalytic converter is 70% or less of the total engine displacement. 4. A jet flow control combustion engine for an automobile, in which the engine according to claim 1 has an idle rotation speed adjusted to 70 Orpm or less.