JPS6350622A - Spark ignition engine - Google Patents

Abstract

PURPOSE:To improve the thermal efficiency of the engine stated in the title specially when it is partially loaded by providing one rotary valve for adjusting the amount of intake air, on an intake passage, another valve for reinducing the exhaust air staying in an exhaust port into a cylinder and one more valve which will open when the pressure in the cylinder is low, on a reinducing passage. CONSTITUTION:A rotary valve 18 linked with the engine speed is to be provided on an intake passage 17 which leads to an intake port 5 located on the upstream from an intake valve 6. The rotary valve 18 has itself an open and close timing adjusting device to control the opening and closing timing specially to quicken the closing timing under a partial load condition to reduce the amount of intake air and lessen the compression work. An exhaust gas passage 9, which is branched off from an exhaust port 7 located on the downstream from an exhaust valve 8, leads to the cylinder through an exhaust gas feeder valve 10. An exhaust gas control valve 11, which is provided on a passage 9 where the exhaust gas in reinduced through, opens when the internal pressure of the cylinder is low to reinduce the exhaust air and raise the air temperature specially under an operating condition when the temperature in the cylinder becomes low with a partial load.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a spark ignition engine (hereinafter referred to as engine), and particularly to a spark ignition engine that can increase the compression start temperature without throttling loss during partial load.

<Prior art> A well-known spark ignition engine is a prime mover that requires the intake of a mixture with a stoichiometric mixture ratio, which enables spark ignition; however, under partial load, the throttle valve This adjusts the intake amount of air-fuel mixture and the output.

<Problems to be Solved by the Invention> However, the above-mentioned adjustment using the throttle valve causes a throttling loss proportional to the negative pressure caused by the throttle, which reduces the thermal efficiency of the engine at partial load, and is particularly useful for automobile engines. When a vehicle is driven under a low load of about one-sixth of the full load during steady running, the throttling loss is large and the thermal efficiency of the engine is reduced.

On the other hand, in view of the above, by using an engine equipped with an intake system without a throttle valve, the intake passage is closed at point 2 (atmospheric pressure and atmospheric temperature) in the middle of the intake stroke to limit the intake amount of the mixture, as shown in Figure 6. Attempts are being made to apply the so-called Miller cycle.

However, the Miller cycle expands adiabatically from point 2 to 3 in Figure 6, compresses adiabatically from point 3 to 4 again, and returns to atmospheric pressure at point 4.
The temperature at point 5 reaches the atmospheric temperature, and since the compression stroke substantially begins from this point and adiabatic compression is carried out from point 4 to point 5, the temperature at point 5 does not reach the temperature required for ignition and combustion.

Incidentally, in an engine whose output is adjusted by a normal throttle, the energy loss due to the throttle, that is, the point 1-2'-3 in Figure 6.
The temperature at point 3 becomes atmospheric temperature due to the loss of energy represented by the area surrounded by the line connecting -4-1, and during compression from point 4 to point 5, the temperature rises to a temperature sufficient for ignition.

In view of the above, the present invention was devised for the purpose of increasing the temperature of the air-fuel mixture and ensuring preferable combustion when the engine is under partial load.

<Means for Solving the Problems> To explain the present invention using FIGS. 1 to 5 corresponding to embodiments, a rotary valve 18 is provided in the intake passage 17 that is opened and closed by the intake valve 6, and the rotary valve 18 is opened and closed. Timing adjustment means 100
In addition, an exhaust gas passage 9 is provided in the cylinder head 5 in parallel with the exhaust port 7 and opened and closed by the exhaust gas supply valve 10, and the exhaust gas supply valve 10 is It opens when the gas pressure in the cylinder 1 is lower than the pressure in the exhaust passage 15 to adiabatically compress the air-fuel mixture in the cylinder.

<Function> With the above configuration, when the engine is under partial load, if the rotary valve 18 is closed in the middle of the intake stroke by the opening/closing timing adjusting means 100 while the intake valve 6 is open, the mixture in the cylinder is reduced during the subsequent intake stroke. Air expands adiabatically and becomes negative pressure. Here, the exhaust gas supply valve 10 is opened to supply exhaust gas into the cylinder 1, thereby adiabatically compressing the air-fuel mixture in the cylinder 1 to increase its temperature and mix it with the high-temperature exhaust gas.

The temperature of the mixture at the beginning of the compression stroke is raised to a temperature sufficient for spark ignition at the beginning of the compression stroke.

<Example> Embodiments of the present invention will be described in detail below based on the drawings.

Basically, as shown in FIG. 1, the spark ignition engine of the present invention has a piston 3 having a piston ring 2 sliding in a cylinder 1, and a connecting rod (not shown) driving a crankshaft (also not shown). 4 In the cylinder head 4 attached to the upper part of the thermo cylinder 1, an intake boat 5, an intake valve 6 that opens and closes it, an exhaust valve 8 that opens and closes the exhaust port 7, and an exhaust valve 8 that opens and closes the exhaust port 7 are formed between the two valves 6 and 8. An exhaust gas supply valve 10 that opens and closes an exhaust gas passage 9 communicating with the exhaust port 7, and an exhaust gas adjustment valve 11 that controls the exhaust gas flow rate within the exhaust gas passage 9 are provided. Further, in the embodiment, a rectifying section 9a is formed in a part of the exhaust gas passage 9 to generate a vortex in the exhaust gas supplied into the cylinder 1. The exhaust gas control valve 11 is rotatably provided on @12 supported by the cylinder head 4, as shown in FIG.
By rotating the lever 13 fixed to the cylinder 1, the amount of exhaust gas supplied into the cylinder 1 is adjusted as described above.

Note that 14 is an exhaust pipe connected to the exhaust port 7 on the side surface of the cylinder head 4;
The exhaust pipe 14 constitutes an exhaust passage 15.

An intake pipe 16 having a mixture forming device such as a carburetor (not shown) is connected to one end of the intake boat 5, and a rotary valve 18 is connected to an intake passage 17 consisting of the intake pipe 16 and the intake boat 5. installed, engine E
Gear transmission mechanism (not shown) from the crankshaft (not shown)
It is configured to be driven through the

FIG. 2 shows a cross section taken along the line A-A in FIG.
It shows. Specifically, the rotary valve 18 is fixed by a pin 20 to a drive shaft 19 supported within a valve body 6a formed in the middle of the intake pipe 16. The drive shaft 19 is connected to a pair of sleeves 21 disposed to sandwich the rotary valve 18 within the valve body 6a.
It is supported by a plurality of bearings 23 via a single sleeve 22, and a left-handed helical spline 19a is formed at one end thereof.

Reference numeral 24 denotes a timing gear that is conductively connected to a crankshaft (not shown) through a gear mechanism (also not shown), and the right end of a rotating shaft 25 that is integrated with the gear is attached to the engine via a bearing 26. A protrusion 28a is supported by the bracket 27, has a right-handed helical spline 25a cut at its left end, engages with both the splines 19a, 25a on the inside, and is slidable in the axial direction between the left-handed helical spline 19a; A conductive connection is made by an adjustment piece 28 formed with a reference numeral 28b. Note that 29 is a return spring for the adjustment piece 28.

30 is an adjustment lever supported by #31, the lower end of which is slidably fitted into the recess 28c of the adjustment piece 28, and the upper end of which is connected to the engine output adjustment mechanism (
(not shown), for example to a governor or an accelerator pedal in an automobile. Therefore, when the adjustment lever 30 is rotated clockwise by the link 32, the adjustment piece 28 is moved to the left, and the protrusion 28a of the adjustment piece 28 and the 23
)) A phase difference is provided between the rotating shaft 25 and the drive shaft 19 by the helical splines 19a and 25a meshing with the helical splines 19a and 25a. That is, the drive shaft 19 is rotated in a direction to advance the closing timing of the rotary valve 18. Therefore, the actual intake stroke of the engine is shortened as shown by line 1-2 in FIG.
By reducing the intake amount of the mixture, it is possible to adjust the output without having to adjust the intake amount of the mixture using a throttle, which is essential for ordinary spark ignition engines.

In the example shown in FIG. 1, the rotary valve 18 has a valve opening period of about 90', and is driven by the timing gear 24 at a rotation speed of one half of the crankshaft rotation. However, if the rotary valve 18 is driven at a rotation speed of one-fourth of the crankshaft, the valve opening period may be set to approximately 45 degrees.

By the way, the opening/closing timing adjustment means 1oO of the rotary valve 18 used in the spark ignition engine of the present invention is limited to the adjustment lever 30 and the adjustment piece 28 that is movable in the axial direction and engaged with the helical splines 19a, 25a. Any structure that can adjust the opening timing of the rotary valve 18 according to the speed of the engine E or the load without any problem can be used in the spark ignition engine of the present invention without any problem.

Further, the exhaust gas control valve 11 is not limited to a butterfly valve, and adjusts the amount of exhaust gas supplied into the cylinder from the exhaust gas supply valve 10, which is opened near the bottom dead center of the engine's intake stroke. As long as it's uruchino, the format doesn't matter.

Next, the operation of the above embodiment will be explained.

FIG. 3 shows the relationship between the opening/closing timing and the opening area of the intake valve 6, exhaust valve 8, exhaust gas supply valve 10, and rotary valve 18 of the engine shown in FIG.

During full load operation, the rotary valve 18 and the intake valve 6 are set to open and close at the same time, so the exhaust gas supply valve 1
0 opens near the bottom dead center of the intake stroke, but in this case, the exhaust gas passage 9 is closed by the exhaust gas control valve 11, so no exhaust gas is supplied, and the engine is essentially no different from a normal engine. Nothing will change.

When the engine load is low, which is a problem, in the engine of the present invention which does not perform intake throttling, intake is started by opening the intake valve 6 from the top dead center 1 of the intake stroke, as shown in FIGS. 3 and 4, and at this time, the rotary If the valve closing timing of the valve 18 is advanced from point A in FIG. 3 to point A by the opening/closing timing adjustment means 100, the amount of air-fuel mixture taken into the engine will be compared to the full load line 1-7 in FIG. , line 1-2. That is, the output can be adjusted by adjusting the closing timing of the rotary valve 18. At this time, the air-fuel mixture sucked into the cylinder 1 expands adiabatically from point 2 in FIG. 4 while the pressure and temperature inside the cylinder 1 continue to decrease. When the piston 3 approaches the bottom dead center, the exhaust gas supply valve 10 opens as shown in FIG. 3, and exhaust gas is supplied into the low pressure cylinder 1. The amount of exhaust gas supplied at this time is regulated by the exhaust gas control valve 11.

In the state of point 3 in FIG. 4, as shown in FIG.
By opening, exhaust gas is supplied into the cylinder 1, and the air-fuel mixture in the cylinder 1 is adiabatically compressed to pressure point 4 in FIG. 4, as shown in FIG. 5(b), and P4. T4' and the pressure and temperature increase. The exhaust gas pressure in cylinder 1 is naturally P4, and the exhaust gas pressure at partial load (approximately 500
C) is mixed with the air-fuel mixture at temperature T4', the temperature at the beginning of the compression stroke is raised to T4, and the temperature T6 after the compression stroke becomes the optimum temperature for ignition and combustion (FIG. 5(C)).

When the straightening section 9a is provided in a part of the exhaust gas passage 9, the exhaust gas supplied through the straightening section 9a can generate a vortex in the air-fuel mixture as shown by the dotted line in Figure 1.

<Effects of the Invention> As described above, the present invention provides a rotary valve in the intake passage which is opened and closed by the intake valve, and uses an opening/closing timing adjusting means to adjust the opening/closing timing of the rotary valve so that the air-fuel mixture is stopped after being sucked in according to the load.
An exhaust gas passage is provided in the cylinder head that is opened and closed by an exhaust gas supply valve installed in parallel with the exhaust passage, and the exhaust gas supply valve is opened when the gas pressure in the cylinder is lower than the pressure in the exhaust passage to insulate the air-fuel mixture in the cylinder. Since it is compressed, the amount of air-fuel mixture intake can be adjusted appropriately according to the load by closing the rotary valve during the intake stroke.

In addition, the temperature drop caused by adiabatic expansion after the rotary valve closes is compensated for by the high-temperature exhaust gas supplied through the exhaust gas supply valve, making it possible to create an air-fuel mixture that provides good combustion. This has the effect of providing a spark ignition engine with substantially no throttling loss over time and with high thermal efficiency, especially at partial load.

Further, according to the present invention, during one partial load, the exhaust gas that passes through the rectifier attached to a part of the exhaust gas passage and recirculates generates a vortex in the air-fuel mixture, increasing the combustion speed and combustion efficiency. This results in a spark ignition engine with high thermal efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal cross-sectional view of a four-samogin according to the present invention, FIG. 2 is a view corresponding to the AA cross section in FIG.
The figure shows an intake valve for an engine according to the present invention. Figure 4 is a p-vm diagram of the engine according to the present invention, and Figure 5 is a diagram showing the opening/closing timing of the exhaust valve, exhaust gas supply valve, and rotary valve, and the opening area of the valves. Figure 6 is an explanatory diagram of the principle of how the state of the air-fuel mixture in the cylinder changes when the engine is under partial load. Figure 6 shows a normal engine that adjusts the output using a throttle valve, and a normal engine that does not have a throttle in the middle of the intake stroke and adjusts the output by closing the intake passage. p-v compared with the engine
Line diagram. 1; Cylinder, 3; Piston, 4; Cylinder head, 5
; Intake port, 61 Intake valve, 7; Exhaust port, 8; Exhaust valve, 9; Exhaust gas passage, 10; Exhaust gas supply valve, 14;
Exhaust pipe, 15; Exhaust passage, 16; Intake pipe, 17; Intake passage, 18; Rotary valve, 100; Opening/closing timing adjusting means, 19; Drive shaft, 19a; Left-hand thread helical spline,
24: Timing gear, 25: Rotating shaft, 25a: Right-handed helical spline, 28: Adjustment piece, 30: Adjustment lever. 31: Axis, 32: Link, E: Engine. Page 5, Figure 6

Claims (1)

[Claims] 1) A rotary valve is provided in the intake passage which is opened and closed by the intake valve, and an opening/closing timing adjustment means is used to adjust the opening/closing timing to close the air-fuel mixture after intake, and a rotary valve is provided in the cylinder head in line with the exhaust passage. The exhaust gas passage is opened and closed by an exhaust gas supply valve, and the exhaust gas supply valve is opened when the gas pressure in the cylinder is lower than the pressure in the exhaust passage to adiabatically compress the air-fuel mixture in the cylinder. spark ignition engine. 2) The spark ignition engine according to claim 1, wherein an exhaust gas regulating valve is installed in the exhaust gas passage.