JPH08135515A - Engine - Google Patents

Abstract

PURPOSE: To improve an intake charging efficiency of an engine so as to improve engine efficiency by injecting water in a cylinder at the end of each exhaust stroke of the engine. CONSTITUTION: In the exhaust stroke of an engine, hot exhaust produced in an explosive stroke is forced out from an exhaust port 5 to an exhaust manifold by the rise of a piston 1. Even at the final stage of the exhaust stroke, hot exhaust remains in a piston clearance of approx. 1/10, for example, of a piston stroke displacement, where a compression ratio is 11. To improve this, a water supply-pipe is passed from a water reservoir 10 to a water injection nozzle 9, a plunger pump 11 to feed water intermittently is connected, and water is sprayed in residual exhaust at the end of the exhaust stroke for evaporation. By this, the hot exhaust is forced out from an exhaust port 5 as far as possible, and the temperature of residual gas as mixed gas of exhaust and water vapor is lowered, whereby the weight of sucked air is increased. Thus an intake charging efficiency is increased so as to increase the engine efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a spark ignition type or compression ignition type four cycle engine which uses gasoline, light oil, heavy oil, city gas or the like as fuel.

[0002]

2. Description of the Related Art As a method for improving the thermal efficiency of an engine, a supercharger that uses the energy of exhaust gas to boost the pressure of intake air has been widely used. However, although the supercharger has a large effect of improving the engine output, the improvement of the engine efficiency is only about a few percent, and especially for the stationary engine, the improvement of the engine efficiency is better than the improvement of the engine output. It is strongly requested.

[0003]

Generally, at the final stage of the exhaust stroke of a four-cycle engine, a certain amount of hot exhaust gas remains in the cylinder, which raises the temperature of the air-fuel mixture or combustion air that is taken in in the next stroke. As a result, the intake charging efficiency is reduced, which is an obstacle to improving the engine efficiency. In view of the above points, the present invention has an object to provide a means capable of improving the intake charge efficiency of an engine by a relatively simple and inexpensive structure and improving the engine efficiency.

[0004]

In the exhaust stroke of the engine, the high temperature exhaust generated in the explosive stroke is pushed out of the exhaust port 5 into the exhaust manifold due to the rise of the piston 1, and even in the final stage of the exhaust stroke. The high temperature exhaust gas remains in a clearance volume of, for example, about 1/10 of the stroke capacity (when the compression ratio is 11). Therefore, claim 1 or 2
The invention of No. 1, as shown in FIG. 1 or 2, by spraying water into this residual exhaust gas at the end of the exhaust stroke to vaporize it,
The hot exhaust gas is pushed out through the exhaust port 5 as much as possible, and the temperature of the residual gas which is a mixed gas of the exhaust gas and water vapor is lowered.
As a result, the weight of the air taken in is increased, and in the invention of claims 3 and 4, as shown in FIG. 3 or 4, compressed air is blown into the cylinder 2 at the end of the exhaust stroke. By doing so, the high temperature exhaust gas is replaced with low temperature air.

[0005]

According to the first or second aspect of the invention, the water droplets sprayed in the cylinder 2 at the end of the exhaust stroke deprive the heat of vaporization from the high temperature exhaust gas in the cylinder 2 to be vaporized and remain in the cylinder 2. Lower the temperature of the mixed gas with the exhaust gas,
Thereby, the temperature rise of the air-fuel mixture or the combustion air sucked into the cylinder 2 in the next stroke can be reduced and the total weight thereof can be increased. Further, according to the configurations of claims 3 to 4, the compressed air blown at a pressure higher than the back pressure in the cylinder 2 during the exhaust stroke expels most of the exhaust gas in the clearance volume to increase the temperature in the cylinder 2. Because it lowers
In addition to suppressing the temperature rise of the intake air in the next stroke and increasing its weight, the air itself blown in this way can also contribute to the explosion as combustion air, so engine efficiency can be further enhanced.

[0006]

1 and 2 show an embodiment in which the present invention is applied to a spark ignition type or compression ignition type four-cycle engine, in which a cylinder head 3 is attached to an upper end surface of a cylinder 2 in which a piston 1 is slidably fitted. The cylinder head 3 is provided with an intake port 4, an exhaust port 5, and a spark plug insertion port or a fuel injection port 8.
The intake port 4 and the exhaust port 5 are provided with an intake valve 6 and an exhaust valve 7, respectively, and the spark plug insertion port or the fuel injection port 8 is equipped with a spark plug or a fuel injection nozzle. A water injection nozzle 9 is provided in the vicinity of the spark plug insertion port 8 of the cylinder head 3, and a plunger type pump 11 for intermittently supplying water from a water storage tank 10 through a water supply pipe is provided in the water injection nozzle 9. Power is transmitted to the pump 11 from the crankshaft 15 via the injection timing adjuster 12, and water is sprayed into the cylinder 2 at the end of each exhaust stroke of the engine. The water injection nozzle 9, the pump 11, and the injection timing adjuster 13 have substantially the same structure as that for fuel injection of a diesel engine.

In FIG. 1 (b), the high temperature (about 700 ° C.) exhaust gas remaining in the clearance space between the piston 1 and the cylinder head 3 at the end of the exhaust stroke is pushed out to the exhaust port 5 while swirling. However, the atomized water droplets injected into the region α on the upstream side of the spiral change to steam while removing the heat of vaporization from the surrounding exhaust gas, so that the gas that finally remains in the clearance volume is It becomes a low temperature (about 200 ° C.) mixed gas containing a large amount of water vapor in the exhaust gas. Therefore, when the compression ratio = 11, that is, when the stroke volume is 10 times the clearance volume, the temperature rise due to the residual gas in the air sucked in the next stroke is reduced by (700 ° C.-200 ° C.) / 11 = 46 ° C. As a result, the weight of the air-fuel mixture or combustion air pushed into the cylinder is increased.
%, The efficiency of the engine can be improved to about 35 to 35.5% (improvement rate of 3.0 to 4.5%). This is comparable to the exhaust heat recovery efficiency of 4 to 5% by the supercharger. FIG. 2 shows another embodiment. Instead of penetrating the water injection nozzle 9 in the cylinder head 3, the exhaust port 5 is provided inside the exhaust manifold 14 connected to the exhaust port 5.
The water injection nozzle 9 is disposed toward the side of the cylinder head 3, which is effective when it is difficult to take a space in the cylinder head 3.

In the embodiment shown in FIG. 3, compressed air is used as the coolant instead of water. An air injection valve 15 is mounted in the vicinity of the ignition plug insertion opening 8 of the cylinder head 3, and this air injection valve 15 is used. 3 to 4 kg / c to supply compressed air to
A m2 compressor 16 is provided, and the injection timing adjuster 13 operates the air injection valve 15 at the end of each exhaust stroke of the engine. 17
Is a filter for preventing the air injection valve 15 from being clogged with dust. Further, in the embodiment of FIG. 4, an air injection valve 15 is arranged toward the exhaust port 5 in the exhaust manifold 12 that is connected to the exhaust port 5. If the air supplied to the compressor 16 is taken from the downstream side of the supercharger, the compressor 16 can be downsized.

According to the configuration of FIG. 3 or 4, the compressed air blown into the clearance space above the cylinder 2 at a pressure higher than the back pressure in the cylinder 2 (for example, about 2 kg / cm 2) during the exhaust stroke. Since most of the exhaust gas in this clearance space is expelled to lower the temperature in the cylinder 2,
As in the case of 2, the expansion due to the temperature rise of the intake air in the next stroke can be suppressed to increase its weight, and the air itself blown into the clearance space can also contribute to combustion.
The engine efficiency can be further enhanced.

[0011]

According to the present invention of claim 1 or 2, as described above, by spraying and vaporizing water in the cylinder 2 at the end of the exhaust stroke, the high temperature exhaust gas is replaced with steam as much as possible and the clearance volume is increased. There is an advantage that the temperature of the mixed gas of the exhaust gas and water vapor remaining in the exhaust gas can be lowered, and thereby the weight of the intake gas mixture can be increased to improve the intake charging efficiency, and the invention of claim 3 or 4 According to this, by blowing the compressed air into the cylinder 2 at the end of the exhaust stroke, the high temperature exhaust can be replaced by the low temperature air, and the intake charging efficiency can be improved in the same manner as above, and in addition, it is blown. Since air can also contribute to the explosion as combustion air, there is an advantage that the engine efficiency can be further enhanced.

[Brief description of drawings]

1A and 1B show an embodiment of the present invention, in which FIG. 1A is a vertical sectional view and FIG.

2A and 2B show another embodiment of the above, in which FIG. 2A is a vertical sectional view and FIG.

FIG. 3 is a longitudinal sectional view of a main part of still another embodiment of the same.

FIG. 4 is a longitudinal sectional view of a main part of still another embodiment of the above.

[Explanation of symbols]

 1 Piston 2 Cylinder 3 Cylinder Head 4 Intake Port 5 Exhaust Port 6 Intake Valve 7 Exhaust Valve 8 Spark Plug Insertion Port or Fuel Injection Port 9 Water Injection Nozzle 10 Water Storage Tank 11 Pump 12 Crankshaft 13 Timing Adjuster 14 Exhaust Manifold 15 Air Injection Valve 16 Compressor 17 Filter

Claims (4)

[Claims] 1. A four-cycle engine in which a cylinder head is provided on an upper end surface of a cylinder in which a piston is slidably fitted, and the cylinder head is provided with an intake port and an exhaust port as well as a spark plug insertion port or a fuel injection port. An engine in which a water injection nozzle is provided through the head and a pump which intermittently supplies water to the water injection nozzle is provided to inject water into the cylinder at the end of each exhaust stroke of the engine. 2. A four-cycle engine in which a cylinder head is provided on an upper end surface of a cylinder in which a piston is slidably fitted, and the cylinder head has an intake port and an exhaust port as well as a spark plug insertion port or a fuel injection port. At the end of each exhaust stroke of the engine, a water injection nozzle is installed in the exhaust manifold connected to the exhaust port toward the exhaust port, and a pump that intermittently supplies water to the water injection nozzle is provided. An engine configured to inject water into the cylinder. 3. A four-cycle engine in which a cylinder head is provided on an upper end surface of a cylinder in which a piston is slidably fitted, and the cylinder head is provided with an ignition plug insertion port or a fuel injection port together with an intake port and an exhaust port. An engine in which an air injection valve is provided through the head, a compressor for supplying compressed air to the air injection valve is provided, and the air injection valve is operated at the end of each exhaust stroke of the engine. 4. A four-cycle engine in which a cylinder head is provided on an upper end surface of a cylinder in which a piston is slidably fitted, and the cylinder head has an intake port and an exhaust port as well as a spark plug insertion port or a fuel injection port. An air injection valve is provided in the exhaust manifold connected to the exhaust port toward the exhaust port, and a compressor that supplies compressed air to the air injection valve is provided. An engine designed to operate at the end of a stroke.