JPH0674745B2 - 5 cycle internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a 5-cycle internal combustion engine used as an automobile gasoline engine, an automobile diesel engine, or the like.

(Prior Art) As a conventional internal combustion engine, for example, “Automotive Engineering Complete Book 4
As described in "Rolled Gasoline Engine" (published by Sankaido Co., Ltd. in July, 1980) is known.

Among the conventional internal combustion engines, the most common and currently frequently used 4-cycle gasoline engine is an engine that performs four strokes of an intake stroke, a compression stroke, an explosion stroke, and an exhaust stroke while the engine makes two revolutions. Is.

In the exhaust stroke, the exhaust valve is opened at the same time as the piston moves to the upward stroke, and the expanded combustion gas is discharged.

(Problems to be Solved by the Invention) However, in such a conventional 4-cycle gasoline engine, when the piston reaches the top dead center, the exhaust action is almost finished, and the combustion gas is generated in the cylinder space at the top dead center. However, due to this residual combustion gas, the intake air-fuel mixture is reduced by the amount of the residual combustion gas even when the process proceeds to the next intake stroke, and the engine output decreases accordingly.

As shown in FIG. 4, the compression ratio ε is ε = (Vh + Vc) / Vc Vh; Exhaust gas volume (stroke volume) that the piston removes in one stroke Vc; Exhaust gas remaining at the piston top dead center Volume (clearance volume).

Then, particularly in an engine in which a device such as a converter or a muffler having a high gas passage resistance (exhaust resistance) is installed in the exhaust system, the residual combustion gas is not sufficiently discharged due to the influence of the exhaust resistance, and therefore the density thereof increases, Much combustion gas will remain. For this reason, exhaust system mufflers and converters are designed to have as low a resistance as possible, but there is still a limit to lowering the resistance value. The output loss reaches from several% to 10% of the engine output.

In other words, the exhaust resistance directly affects the loss of the engine output, which causes the following problems.

(B) The exhaust system muffler is designed to reduce exhaust noise by combining various muffling principles. However, in all mufflers, there is a strong correlation between the degree of noise reduction and exhaust resistance, and exhaust muffler is generally used. A muffler with high resistance has low exhaust noise. Moreover, in recent years, a vehicle with quieter exhaust noise due to noise pollution has been required, and therefore exhaust resistance tends to increase, and the loss of engine output due to the above-mentioned residual combustion gas increases with the increase in exhaust resistance.

(B) In the heat balance of an internal combustion engine, 30
About% is discarded in the exhaust. Therefore, it is very meaningful to collect and effectively use this exhaust energy from the viewpoint of energy saving. Therefore, it is conceivable to provide an exhaust gas turbine or the like in the exhaust system in order to recover heat, but any method will increase exhaust resistance and lead to loss of engine output. It was practically difficult to recover the exhaust energy because the engine output was lost more than the recovered energy.

Further, as a conventional internal combustion engine, for example, pages 156 to 1 of "Automotive Engineering Complete Book 4 Vol.
There is known a turbocharged gasoline engine equipped with a turbocharger as described in page 63, Japanese Utility Model Publication No. 60-178329, etc.

This turbocharged gasoline engine uses exhaust gas to rotate a turbine, and a compressor mounted coaxially to the turbine increases the intake pressure to increase the engine output, especially in a high-speed rotation range. .

However, this turbocharged gasoline engine aims to increase the engine output by paying attention to the intake side, but the loss of the engine output due to the residual combustion gas as described above is exactly the same, and this loss is The exhaust resistance is increased by providing the turbine in the exhaust system, and in this respect, the loss of the engine output due to the residual combustion gas is larger than that of the engine without the turbocharger. However, the merit of increased output obtained by supercharging is only bought and put to practical use.

(Means for Solving Problems) The present invention solves the problems described above, that is, eliminates loss of engine output due to residual combustion gas,
The purpose of this invention is to eliminate the influence of exhaust resistance on the output. To achieve this purpose, the present invention performs five strokes of intake, compression, explosion, exhaust, and scavenging during two revolutions of the engine. In a 5-cycle internal combustion engine in which a scavenging pump that creates pressurized air for discharging residual combustion gas is used in the scavenging stroke when the exhaust valve is opened, the scavenging pump is a positive displacement type driven directly by the engine, and the total clearance of the engine is When the volume Vc ^* , the number of revolutions N and n of the engine and the scavenging pump per unit time, and the scavenging coefficient k, the displacement Vp per one revolution of the scavenging pump is expressed by And the scavenging coefficient k is set in the range of 0.8 to 2.5.

(Operation) Therefore, in the five-cycle internal combustion engine of the present invention, by adopting the above-mentioned means, the exhaust valve is opened and the piston is raised, and the pressurization by the scavenging pump is performed subsequent to the exhaust stroke for discharging the combustion gas. A scavenging stroke is performed in which air is injected into the cylinder to forcibly discharge residual combustion gas to the outside.
Pressurized air remains in the clearance volume at the top dead center of the piston instead of the residual combustion gas, and in the subsequent intake stroke, the total cylinder volume becomes the effective intake volume of the air-fuel mixture, eliminating the loss of engine output due to the residual combustion gas. You can

Further, as described above, the residual combustion gas is discharged to the outside by the forced scavenging action, so that the direct influence of the exhaust resistance on the engine output can be eliminated.

Further, in the displacement type scavenging pump, if the engine is directly driven, the rotation thereof is completely proportional to the rotation of the engine at a constant ratio.
Moreover, since the displacement per revolution of the positive displacement scavenging pump is constant, the amount of pressurized air injected into the cylinder does not change significantly due to changes in the engine speed. If k is set in the range of 0.8 to 2.5, the required amount of pressurized air can be secured from low speed to high speed of the engine. Therefore, there is no need to control the amount of pressurized air at low speed. The increase of the engine torque and the increase of the engine output at high speed are easily achieved.

(Examples) Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In describing this embodiment, a 5-cycle gasoline engine used as an automobile engine will be taken as an example.

First, the configuration of the embodiment will be described.

The 5-cycle gasoline engine A of the embodiment has a cylinder 1, a piston 2, an intake pipe 3, an intake valve 4, an exhaust pipe 5, an exhaust valve 6, a scavenging pipe 7, and a scavenging valve, as shown in FIGS. 1 to 4. 8 and a positive displacement air compressor (scavenging pump) 9 are the main components.

The cylinder 1 is a cylindrical cylinder formed in a cylinder block, and the cylinder arrangement in the case of having a plurality of cylinders includes L type (series type), V type, opposed piston type and the like.

The piston 2 is provided in the cylinder 1 so as to be capable of reciprocating, and the piston 2 is connected to a crankshaft 12 via a connecting rod 10 and a crank arm 11.

The intake pipe 3 is a pipe into which a mixture of air and fuel is sucked. An intake hole 13 of the intake pipe 3 is opened in the cylinder head portion 1a of the cylinder 1, and a cam is provided at the position of the intake hole 13. An intake valve 4 is provided which opens and closes in response to rotation of the shaft.

The intake pipe 3 is provided with a carburetor 19 and a fuel injection nozzle 20.

The exhaust pipe 5 is a pipe for discharging combustion gas after explosive combustion to the outside, and an exhaust hole 15 of the exhaust pipe 5 is opened in the cylinder head portion 1a of the cylinder 1, and the exhaust hole 15 is located at a position of the exhaust hole 15. An exhaust valve 6 that opens and closes according to the rotation of the camshaft and the like is provided.

The scavenging pipe 7 is a pipe for injecting pressurized air from the positive displacement air compressor 9 into the cylinder 1 when the exhaust valve 6 is open at the end of the exhaust stroke in the case of a 4-cycle internal combustion engine. A scavenging hole 17 of the scavenging pipe 7 is opened in the cylinder head portion 1a of the cylinder 1, and a scavenging valve 8 which is opened / closed at a position of the scavenging hole 17 in accordance with rotation of a cam shaft or the like is provided. ing.

In the embodiment, the intake holes 13, the exhaust holes 15, and the scavenging holes 17 are arranged so that the exhaust holes 15 and the scavenging holes 17 are arranged in a triangle as shown in FIG. The valve 8 is provided with a scavenging guide plate 81, and as shown by the arrows in FIG. 3 and FIG. 4, the injection path of the pressurized air is a path that goes around the space of the cylinder 1 along the inner peripheral surface, and the combustion gas Scavenging efficiency is improved.

The positive displacement air compressor 9 is provided in the middle of the scavenging pipe 7 and is a means for generating pressurized air with a pressure and volume sufficient to eliminate residual combustion gas in a short time. Directly connected to the crankshaft 12 via a speed change mechanism 18 such as a belt mechanism or a gear mechanism,
It is driven directly by the engine.

The positive displacement air compressor 9 is an air compressor of a type in which the displacement of each stroke is quantified by the volume of a cylinder or the like, and is a reciprocating type (crank type, swash plate type).
There are air compressors, rotary air compressors, and roots blowers.

The displacement Vp per revolution of the positive displacement air compressor 9 is based on the total clearance volume Vc ^* of the engine A,
It is rational to determine the scavenging stroke according to the following equation in consideration that it occurs once during two revolutions of the engine A.

Vp; Displacement per revolution of positive displacement air compressor 9 (c
c) N: Number of revolutions of engine A (rpm) n; Number of revolutions of positive displacement air compressor 9 (rpm) Vc ^* ; Total clearance volume (cc) obtained by multiplying the clearance volume Vc of each cylinder of engine A by the number of cylinders ) (For example, in the case of a 6-cylinder engine, Vc ^* = 6 × Vc) k; Scavenging coefficient of the positive displacement air compressor 9 (total clearance volume
Vc ^{* is a} coefficient that determines the practical displacement of the positive displacement air compressor 9) In the above equation, when the scavenging coefficient k is 1, the displacement Vp of the positive displacement air compressor 9 per revolution is And the displacement of engine A in 2 revolutions is the total clearance volume
If it is equal to Vc ^* , therefore, if the scavenging action is ideally performed, it is possible to remove almost 100% of the residual combustion gas to the outside of the cylinder 1, but in reality, part of the compressed air remains. The combustion gas is discharged to the outside of the cylinder, and the residual combustion gas remains in the cylinder by that amount.

Further, if the scavenging coefficient k is 1 or less, complete scavenging is impossible theoretically, but the cost of the compressor itself can be reduced by using a displacement type air compressor 9 having a small displacement. And, because it also has the advantage of reducing the loss of engine output, even if it is 1 or less
Although it is incomplete up to 0.8, the scavenging action can reduce the loss of engine output.

When the scavenging coefficient k is 2, air is supplied twice as much as the total clearance volume Vc ^* for scavenging, so that scavenging can be performed almost completely without using special scavenging means. However, even if it is 2 or less, complete scavenging is possible by increasing the scavenging efficiency.

Further, when the scavenging coefficient k is 2 or more, the pressurized air is injected into the cylinder 1 even after almost complete scavenging, and the driving horsepower of the positive displacement air compressor 9 increases by that amount, which is uneconomical. Since perfect scavenging may be required in particular, it is possible to set up to 2.5th place.

Therefore, if the scavenging coefficient k is in the range of 0.8 to 2.5, a merit due to reduction of engine output loss can be expected.

As described above, by providing the scavenging guide plate 81 on the scavenging valve 8 and appropriately adjusting the position and size of the scavenging valve 8, a sufficient scavenging effect can be expected even when the scavenging coefficient k is about 1.5.

Next, the operation of the embodiment will be described.

First, each process will be described.

(A) Intake stroke When the intake valve 4 is opened, the piston 2 descends from the top dead center, and the air-fuel mixture is sucked into the cylinder 1.

(B) Compression stroke Next, the piston 2 rises from the bottom dead center. At this time, both the intake valve 4 and the exhaust valve 6 are closed, and the air-fuel mixture is compressed and its temperature and pressure rise.

(C) Explosion stroke Just before the top dead center at the end of the compression stroke, the mixture is ignited by the spark plug. Then, the high-pressure gas generated by the combustion pushes the piston 2 downward to work.

(D) Exhaust stroke In the next rising stroke of the piston 2, the exhaust valve 6 is opened and the expanded combustion gas is discharged to the atmosphere.

(E) Scavenging stroke When the piston 2 is near the top dead center or reaches the top dead center in the exhaust stroke of the piston 2, the scavenging valve 8 is opened and pressurized air is injected into the space of the cylinder 1 to cause residual combustion. In the process of forcibly discharging the gas to the outside, the exhaust valve 6 closes and the scavenging process ends.

The effective suction volume of the air-fuel mixture becomes the total cylinder volume by the scavenging process. At this time, in the intake stroke, the pressurized air remains instead of the residual combustion gas, so the air-fuel mixture has a higher concentration than before, and when the air is taken into the cylinder 1, it remains the same as before. It is necessary to adjust the fuel supply system so that the mixture has a concentration, and the fuel amount is almost Becomes

Next, the theoretical calculation of output gain and output loss will be described.

[Apparatus] 2000cc 6-cylinder gasoline engine Compression ratio 8 Maximum output 120Hp Assuming that there is an output loss of 5% to 15% due to residual combustion gas, although it depends on load, rotation speed, exhaust system resistance, etc. 126H with this engine if solved
The output shall be p to 140Hp.

[Calculation of compressor required power] Adiabatic gas power Lad can be calculated by the following formula.

N; radix of intercooler (in this case, N = 0 without intercooler) K; specific heat ratio (here, K = 1.4 as dry air) Pt ₁ Pt ₂ ; total pressure at inlet and outlet of compressor (here , Considering that the dynamic pressure is smaller than the static pressure, Pt ₁ ,
Static pressure is used instead of Pt ₂ Static pressure Ps ₁ = 1kg / cm ² = 10000kg / m ² Static pressure Ps ₂ ＝ 2kg / cm ² ＝ 20000kg / m ² ) Q; Volume flow of scavenging air m ³ / min ( 1.5 times of Vc) When Lad is calculated from the above, Lad = 1.17KW = 1.6Hp [Conclusion] Assuming that an air compressor with an efficiency of 50% is used, it will be approximately 3Hp
Driving horsepower will be required. Therefore, the engine output of 140Hp is reduced to 137Hp, but the output of 17Hp can still be expected to increase.

As described above, in the 5-cycle gasoline engine A of the embodiment, the scavenging pipe 7 and the scavenging valve 8 are provided, and the residual combustion gas is forcibly discharged to the outside when the exhaust valve 6 is opened.
That is, since the scavenging is performed, the loss of the engine output due to the residual combustion gas is eliminated, and as a result, the engine output can be increased.

Further, since the scavenging system is provided in a system separate from the fuel supply system (the intake pipe 3 etc.), firstly, the scavenging air amount, pressure and scavenging timing can be set most efficiently, and a high scavenging effect can be expected. Secondly, it can be easily applied regardless of the fuel injection engine or the carburetor engine. Third, since scavenging is performed only with air, there is no fuel loss unlike scavenging with a mixture. Fourth, when the intake fluid and the scavenging system are integrated into one system, the flow rate of the air-fuel mixture and the like to be supplied to both must be controlled by opening and closing the valve, whereas the control between the intake system and the scavenging system is performed. Does not need

In addition, since the residual combustion gas is discharged to the outside by the forced scavenging action, it is possible to eliminate the direct influence of the exhaust resistance on the engine output, which greatly increases the degree of freedom in designing the exhaust system. It is possible to actively add an exhaust noise reduction device, an exhaust gas energy recovery device, and the like.

Further, the positive displacement air compressor 9 is a crankshaft.
It is directly connected to 12 via a speed change mechanism 18, and its rotation speed n is completely proportional to the rotation speed N of the engine (crankshaft 12) at a constant ratio, and moreover, it is 1 of the positive displacement air compressor 9.
Since the exhaust amount Vp per rotation is also constant, even if the engine speed N changes, the amount of pressurized air injected into the cylinder 1 does not change significantly, and therefore the control of the pressurized air can be controlled. Even if it is not performed, stable scavenging action is performed, and an increase in engine torque at low speed and an increase in engine output at high speed can be achieved.

Further, in the embodiment, a high scavenging effect can be achieved by the arrangement of the scavenging holes 17 and the scavenging guide plate 81 provided on the scavenging valve 8.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within a range not departing from the gist of the present invention. included.

For example, although a 5-cycle gasoline engine is illustrated in the embodiment, it can be applied to a diesel engine. In this case, it is possible to open the intake valve earlier than usual and perform scavenging by the intake system to which supercharging has been added at the end of the normal exhaust stroke. However, in general, a diesel engine has a compression ratio that is more than twice that of a gasoline engine, so the output increasing effect of a gasoline engine cannot be expected.

Further, in the embodiment, the scavenging pipe and the scavenging valve are used as the scavenging device, but an air injection nozzle or the like may be used.

Further, in the embodiment, the end of the scavenging time is set to the time when the exhaust valve is closed, but the supercharging effect can be expected by keeping the scavenging valve open and continuing the scavenging even after the exhaust valve is closed.

Further, when the knock (abnormal combustion) phenomenon increases due to the application of the present invention, it is effective to provide a cooler for cooling the pressurized air after the air compressor.

Furthermore, if the pressurized air pulsates due to the type or drive method of the air compressor, or if the pressure of the pressurized air that fluctuates due to the engine speed, etc., an accumulator is installed between the air compressor and the engine. It is desirable to provide it.

(Effects of the Invention) As described above, in the five-cycle internal combustion engine of the present invention, while the engine makes two revolutions, five strokes are performed in the order of intake stroke → compression stroke → explosion stroke → exhaust stroke → scavenging stroke. Since the stroke is performed, the residual combustion gas is forcibly scavenged, the loss of the engine output due to the residual combustion gas is eliminated, and the engine output can be increased.

In addition, because the residual combustion gas is discharged to the outside by the forced scavenging action, it is possible to eliminate the direct influence of the exhaust resistance on the engine output, which greatly increases the degree of freedom in designing the exhaust system and reduces the exhaust resistance. An exhaust noise reduction device, an exhaust gas energy recovery device, and the like can be actively added without paying much attention to the increase.

Further, by using a positive displacement scavenging pump as a scavenging pump for producing pressurized air, and further by directly driving the positive displacement scavenging pump by the engine and setting the scavenging coefficient k to 0.8 to 2.5, the low speed of the engine is reduced. You can always supply the required amount of pressurized air up to high speeds, and therefore you can easily increase the engine torque at low speeds and the engine output at high speeds without separately controlling the amount of pressurized air. The effect of being able to be obtained is obtained.

[Brief description of drawings]

FIG. 1 is an overall view showing a 5-cycle gasoline engine of an embodiment of the present invention, FIG. 2 is a plan view showing intake / exhaust / scavenging paths of the engine of the embodiment, FIG. 3 is a plan view showing scavenging action, and FIG.
The drawing is a partial cross-sectional view taken along the line I-I of FIG. 3, and FIG. 5 is an explanatory view of the cylinder volume of the engine. A: 5-cycle gasoline engine (5-cycle internal combustion engine) 1 ... Cylinder 2 ... Piston 4 ... Intake valve 6 ... Exhaust valve 8 ... Scavenging valve 9 ... Positive displacement air compressor 13 ... Intake hole 15 ... … Exhaust holes

Claims (1)

[Claims] 1. A scavenging pump that performs five strokes of intake, compression, explosion, exhaust, and scavenging during two revolutions of an engine, and produces pressurized air for discharging residual combustion gas when the exhaust valve is opened in the scavenging stroke. In the 5-cycle internal combustion engine used, the scavenging pump is a positive displacement type driven directly by the engine, and the total clearance volume Vc ^{* of} the engine, the rotational speeds N and n of the engine and the scavenging pump per unit time, and the scavenging coefficient k If you do, the displacement Vp per rotation of the scavenging pump And a scavenging coefficient k is set in the range of 0.8 to 2.5.