JPS6223530A - Supercharger - Google Patents

Abstract

PURPOSE:To reduce the power consumption and noise of a blower and improve the suction efficiency of a supercharger and endurance of the blower by synchronizing the opening of the suction valves with the curved line of the puls-action of the blower. CONSTITUTION:While the air discharge pressure from a Roots blower is in the range of a first curved line (a) (crank angle: 0 deg. to 180 deg.), the suction valve of a second cylinder and the exhaust valve of a fourth cylinder are opened. In the range of a second curved line (b) (crank angle: 180 deg. to 360 deg.), the suction valve of a first cylinder and the exhaust valve of the second cylinder are opened. In the range of the curved line (a) to (b), with the case where a Roots blower is not provided in a suction route, the air discharge pressure varies as shown in a negative pressure curved line (c) to (d) by the work of the piston descending in cylinders being synchronized with the curved line (a) to (b) of the air discharged pressure from the Roots blower.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an engine supercharging device, and more particularly to a supercharging device that is driven by an engine and forcibly supplies pressurized air to the intake system of the engine. This relates to a feeding device.

[Conventional technology]

As is well known, there are two types of supercharging systems: one in which the high-temperature exhaust gas of the engine drives a turbine, and the turbine drives a compressor, and the other is a type in which the engine is driven by a mechanical drive means such as a gear train, a checkerboard, or a V-belt. The present invention belongs to the latter category.

In the former supercharging device, compressed air is obtained by rotating a turbine at high speed using engine exhaust gas, so pulsation is less likely to occur in the compressed air. However, when a positive displacement blower used in the latter supercharging device, especially a Roots blower, is used, pulsation occurs at the rotational position of the rotor. The magnitude of this pulsation is small when the pressure of the discharged compressed air is high, but becomes large when the pressure is low.

The engine has multiple cylinders, and these cylinders are
They are connected by a wooden, tubular intake manifold, and each cylinder's intake valve opens at its own timing, so the air (mixture) supplied from within the intake manifold is taken in in a pulsating manner.

However, in conventional engine-driven supercharging devices, air is pumped to the intake side of the engine so that the pressure is as uniform as possible by driving the supercharging device asynchronously with each cycle of the engine. That is, even when the intake valve is closed, high-pressure air is fed under pressure, resulting in the following drawbacks.

■ Since the roots blower constantly supplies high-pressure compressed air, the discharge pressure of the Roots blower increases, which increases the discharge temperature and reduces suction efficiency.

(2) Increasing the discharge pressure increases the load on the supercharger itself, reducing its durability and increasing the friction of the air within the supercharger, increasing power consumption.

■ In order to increase the discharge pressure, it is necessary to rotate the supercharging device at high speed, which generates noise, increases friction, and deteriorates durability.

[Purpose of the invention]

The present invention was obtained in order to eliminate the drawbacks of the conventional supercharging device, and its purpose is to:
By lowering the pressure of the compressed air supplied by the supercharger, the power consumption of the supercharger is reduced accordingly, and by lowering the discharge temperature of the compressed air, the suction efficiency is increased. The purpose is to increase durability and reduce noise.

[Summary of the invention]

In order to achieve the above object, the present invention is configured such that an engine drives a blower that generates pulsations in discharged air, and synchronizes the peak of the pulsation with the opening of the intake valve of the engine. It is a supercharging device.

The air compressor used in the present invention must be a positive displacement blower and essentially have pulsation, and it is particularly advantageous to use a Roots blower in the present invention.

The air compressor must be synchronized with the rotation of the engine.
For this purpose, it is advantageous to employ mechanical drive means that precisely synchronize with the rotation of the engine, such as a gear train, a timing belt, or a chain.

It is best to select an engine that produces clear pulsations within the intake manifold during the intake stroke of each cylinder.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram showing a supercharging device according to the present invention,
Intake ports 3 of an engine 2 having a plurality of cylinders 1 are integrally connected by an intake manifold 4, and a throttle valve 5 is provided on the upstream side of the intake manifold 4, and a positive displacement blower is provided further upstream. 6 is provided. The suction side and the discharge side of the volumetric pump 6 are connected through a bypass passage 7, and a bypass valve 8 is provided in the bypass passage 7. The air sucked in from the air intake port 9 is cleaned by an air cleaner 10 and supplied to the positive displacement blower 6. The positive displacement blower 6 compresses the air and compresses the air into the intake manifold 4. It is configured to supply compressed air through the intake port 3 during the intake stroke of the engine 2 as the intake valve opens and closes.

In this embodiment, a roots blower having two rotors is used as the positive displacement blower 6, and a wheel 12 provided on the drive shaft 11 of the roots blower and a wheel 14 provided on the crankshaft or other output shaft 13 of the engine 2 are used. During this period, power is transmitted by the timing belt 15.

FIG. 2 shows the Roots blower 6 and the fluctuations in discharge pressure. The upper side shows the pressure fluctuations of the compressed air A discharged from the Roots blower 6, and the lower side shows the position of the rotor 16.16". As is clear from the figure, there are three peaks in the pressure fluctuation of the compressed air A during one rotation of the rotor 16, 16'.

In this way, in the Roots blower 6, the rotors 16, 16
There is a pressure fluctuation in the discharged air A depending on the position of ``, but this pressure fluctuation is propagated into the intake manifold 4 provided downstream of the Roots blower 6.

Therefore, if the intake valve of each cylinder 1 is opened at the peak of the pressure of discharge air A, pressurized air A can be supplied without making the average pressure of discharge air A very high. It is.

Figure 3 shows the opening timing of the intake and exhaust valves relative to the engine crank angle, the negative pressure in the intake manifold connecting each cylinder (in the absence of a supercharger), and the discharge of a positive displacement blower, that is, the Roots blower. This shows the relationship with pressure.

The first mountain raJ of air A discharged from the roots blower 6
Between (crank angle 00 to 180'),
For example, the intake valve of the second cylinder is open, and the exhaust valve of the fourth cylinder is open.

Between the next second peak rbJ (crank angle is 180° to 36°)
0°), the intake valve of the first cylinder and the exhaust valve of the second cylinder are open.

Between the air pressure peaks a and b, if a supercharger is not installed in the intake path, negative pressure peaks c and d will occur due to the action of the piston descending within the cylinder, but this invention In the supercharging device related to
The feature is that the peaks a and b of the discharge pressure of the supercharger, that is, the Roots blower, are synchronized.

Figure 4 shows the efficiency of a positive displacement supercharger.1. The vertical axis shows the flow rate of compressed air, and the horizontal axis shows the differential pressure (discharge pressure -
It is drawn by taking the cylinder inlet pressure).

As the differential pressure, that is, the discharge pressure increases, the flow rate of compressed air decreases. From this figure, it can be seen that the flow rate of compressed air is the largest when the differential pressure is around zero (therefore, it can be seen that the pump efficiency is the best when air is taken into the engine in this state.

〔Effect of the invention〕

The present invention uses a positive displacement blower with pressure fluctuations as a means for supplying compressed air to the intake manifold of an engine, and drives this by the engine to control the fluctuating discharge pressure of the compressed air discharged from the blower. the location of the mountain,
It is characterized by synchronizing the opening position of the intake valve of the engine.

Therefore, according to the present invention, in order to match the peaks of compressed air delivered from the supercharger in a state where air is most likely to flow into the cylinders of the engine, that is, in a negative pressure state, the differential pressure (discharge pressure - cylinder This makes it possible to inhale air when the inlet pressure (inlet pressure) is near zero.

As shown in Figure 4, when the differential pressure is around zero, the flow rate of compressed air discharged from the blower is large.
The pump efficiency of this blower is good.

Further, when the differential pressure is around zero, the discharge pressure of the blower is low, so the discharge temperature of the blower is low, and the suction efficiency increases.

Since the discharge pressure of the blower can be lowered, the load on the blower is reduced and mechanical friction is also reduced, resulting in improved durability.

Furthermore, the blower is driven in synchronization with the engine's rotation and the peak of compressed air discharged from the blower matches the opening of the engine's intake valve, which can generate noise and reduce durability. There are no drawbacks such as deterioration.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a supercharging device according to an embodiment of the present invention, Fig. 2 is a diagram showing fluctuations in the discharge pressure of a Roots blower, and Fig. 3 is a diagram showing engine crank angle and opening timings of intake and exhaust valves. FIG. 4 is a diagram showing the timing relationship between the pressure fluctuation in the intake manifold and the discharge pressure of the blower, and FIG. 4 is a diagram showing the pump efficiency of the positive displacement supercharger. 1... Cylinder, 2... Engine, 3... Intake boat, 4... Intake manifold, 5... Throttle valve, 6... Positive displacement blower (roots blower), 7...
Pibes passage, 8... Bypass valve, 10... Air cleaner, 15... Timing belt, 16.16"
...rotor.

Claims (1)

[Claims] A supercharging device configured to cause an engine to drive a blower that generates pulsations in discharged air, and to synchronize the peak of the pulsation with the opening of an intake valve of the engine.