JPS5836824Y2 - Exhaust turbo supercharging device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an exhaust turbocharging device.

A conventional exhaust turbocharger will be explained with reference to FIGS. 1 and 2.

In Figures 1 and 2, 1' is the diesel engine body,
A plurality of cylinders 2' are provided in the diesel engine main body 1'.

Reference numeral 5' denotes an exhaust turbine, which collects exhaust gas from each of the cylinders 2' through an exhaust pipe into an exhaust gas collecting pipe 4, and is driven by introducing the collected exhaust gas.

Reference numeral 6' denotes a blower, which is installed coaxially with the exhaust turbine 5' and driven once, takes in outside air, compresses it properly, creates a high volume of air supply, and blows it through the air supply pipe 7' and the air supply manifold 8'. , supply air is supplied to each cylinder 2'.

In FIG. 2, γ is an exhaust bypass pipe, which branches off from the exhaust manifold pipe 4' and communicates with an exhaust muffler (not shown).

Further, a switching valve 10' is provided in the middle of the exhaust bypass pipe 9', and the switching valve 10' is switched by the constant pressure signal 7a' of the air supply pipe γ', so that a portion of the exhaust gas in the exhaust manifold pipe 4' is switched. is discharged to the exhaust muffler (not shown).

In particular, exhaust turbocharged engines for vehicles have a wide operating rotation range, and the load range ranges from low-speed idling operation to low-speed high torque when driving on a hill, and due to the development of expressways, the proportion of high-speed driving is also increasing.

It is difficult to maintain good performance from low speeds to high speeds for such a vehicle engine that has a wide range of operating speeds, and there are the following problems.

(7) Generation of black smoke and insufficient torque in the low speed and high torque range, (a) Decrease in engine durability due to increase in cylinder pressure at high speeds, (
(3) Ensuring low fuel consumption rates, etc.

Figure 1 shows a conventional supercharging system, or if it is designed to increase the rotation of the exhaust turbine to ensure sufficient air supply in the low speed range, prevent the generation of black smoke, and improve the lack of torque. ,
In the high-speed range, the increase in cylinder pressure due to the increase in supply pressure and the increase in pump loss due to the increase in exhaust pressure lead to a deterioration in fuel efficiency.

On the other hand, if you improve performance in the high speed range, you will end up with black smoke and a lack of torque in the low speed range.

In addition, as shown in Figure 2, there is a type in which the exhaust bypass pipe 9' is opened by the switching valve 10' when the supply air pressure is detected and reaches a constant pressure, but this does not cause black smoke in the low speed range. To prevent this, ensure sufficient air supply and match with the blower 6', at high speeds part of the exhaust gas is discharged without passing through the exhaust turbine 5', and the pressure in the exhaust manifold pipe 4' is lowered.
The rotation of the exhaust turbine 5' is reduced to lower the degree of supercharging of the blower 6', thereby preventing an increase in supply air pressure.

However, when considering an exhaust supercharging system that effectively utilizes exhaust energy, the fuel efficiency deteriorates by the amount of exhaust bypassed.

The present invention aims to provide an exhaust turbocharged diesel engine equipped with an efficient supply and exhaust system from low speed range to high speed range. (b) A switching valve is provided so that when a certain value is reached, the exhaust gas from one of the cylinders is not sent to the exhaust turbine and is released into atmospheric pressure. The intake stroke and exhaust stroke of one part of the cylinder are made into a single part of the cylinder, thereby improving the output of the engine as a whole.

The present invention will be explained with reference to FIGS. 3 to 6.

In Fig. 3, 1 is the diesel engine body, 2 is the cylinder, 3 is the exhaust pipe, 4 is the exhaust collecting pipe, 5 is the exhaust turbine,
6 is a blower, γ is an air supply pipe, and 8 is a manifold.

Exhaust pipe 3 of one cylinder 2 among the plurality of cylinders 2
A switching valve 11 is provided in the air supply pipe 7 that communicates with the blower 6, and a detection device 7a for detecting the supply pressure is installed, and a supply pressure signal 7b detected by the detection device 7a is set to a certain constant pressure. For example, the switching valve 11 is operated and closed (until the supply pressure signal γb does not reach a certain pressure, it is open to the exhaust manifold pipe 4 side), and the exhaust manifold is connected from the exhaust pipe 3a where the changeover valve 11 is installed. cutting off the flow path to the exhaust turbine 5 via the pipe 4;
Exhaust gas from the exhaust pipe 3a is made to flow through the switching valve 11 to an exhaust bypass pipe 12 and released into atmospheric pressure.

In addition, in the embodiment shown in Fig. 3, the exhaust pipe of one cylinder is provided with a switching valve. You can also install it in the exhaust pipe (・.

That is, the exhaust turbo supercharging device of the present invention includes an exhaust turbo supercharger, a plurality of cylinders, an exhaust pipe 3 provided in the same number as the cylinders, and an exhaust pipe 3 provided in the same number as the above-mentioned superchargers. In an internal combustion engine equipped with an exhaust manifold pipe 4 connecting an exhaust turbine inlet and each of the exhaust pipes 3, an exhaust pipe 3 between the plurality of exhaust pipes 3 is provided.
A switching valve 11 that is provided close to the cylinder outlet of a part of the exhaust pipe 3a inside and that opens and closes an exhaust bypass passage 12 that communicates with the atmosphere from the cylinder outlet connects the blower outlet of the supercharger and the cylinder. A detection device 1a is provided in the air supply pipe γ, and detects the air supply pressure and transmits an opening/closing signal for the switching valve 11.

Figure 4 shows an example of intake pressure and exhaust pressure with rotation speed NE on the horizontal axis and Mocha on the vertical axis.In the vertical supercharging system shown in Figure 1, as the rotation speed increases, Solid line AI,
As shown by B/, the exhaust pressure Pe is higher than the supply pressure Ps.

In addition, even with the conventional exhaust pipe/kusuji stem shown in Figure 2, the 4th
As shown by dotted lines C' and D' in the figure, the supply air pressure Ps is 1
, Fkg/cyr? 'Ze, the exhaust gas Mocha Pe is about 2k
g/Crr will be about 12.

Also, considering the P-V (EF force, body @) diagram in the cylinder, in the conventional case, as shown in Figure 5, ■' is the compression stroke, 'is the combustion stroke, ■ is the exhaust stroke, and ■ is the exhaust stroke. In the intake stroke, the effective work is expressed as the area surrounded by the compression stroke ■' and the combustion stroke, and the area surrounded by the exhaust stroke ■ and the intake stroke ■ is usually called the pump loss. This becomes a negative work, and the actual effective work done on the outside is the area I' and the ff-surface bond TIf - ■.

Figure 6 shows the P-V of the cylinder equipped with the switching valve 11 of the present invention.
The difference from the conventional system is that, as shown by the dashed line C in FIG.
e suddenly drops to atmospheric pressure, as shown by the two-dot chain line.

Therefore, according to the present invention, there is no pump loss in the exhaust stroke,
In other words, there is no effect of exhaust pressure while the piston is rising, and supply air pressure acts on the piston's descending stroke during the suction stroke, so the area surrounded by III and IV in Fig. 6 or the old work The effective work is the area 1. II + area ■, ■.

According to the present invention, for example, the air supply pressure is 1.5 kg/Cm.
If the switching valve 11 operates at 2, the average effective pressure will be 1.5, even assuming that there is no pump loss in the conventional type.
You will gain 2 kg/cm.

The average effective pressure for a 6-cylinder engine is lokg/cm.
2, if one of the cylinders operates as in the present invention, the output improvement rate (fuel efficiency improvement rate) is expressed as 1 1゜5 X −X −=0.025 0 6 , and 2 This results in a .5% improvement in fuel efficiency, which is an even greater improvement considering the pump loss of conventional pumps.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a conventional exhaust turbo supercharging device, FIG. 3 is an explanatory diagram of an embodiment of the exhaust turbo supercharging device according to the present invention, and FIG. 4 is a diagram of a conventional exhaust turbo supercharging device. The conventional supercharging system shown in Fig. 3 is a curve diagram showing the relationship between supply air pressure and exhaust pressure of the exhaust turbo supercharging device of the present invention shown in Fig. 3, and Figs. FIG. 2 is a diagram showing the relationship between mocha and volume in a cylinder according to the feeding system and the present invention. In the figure -L-, 1...The main body of the tasel engine. 2...Cylinder. 3...exhaust pipe. 4...Exhaust collecting pipe. 5
...Exhaust turbine. 6...Blower. 7...Air supply pipe. 8... Manifold. 7a... Device that detects air supply pressure. γb...Buff pressure signal. 11...Switching valve. 12...Bypass pipe. 3a...Exhaust pipe in which the switching valve 11 is installed.

Claims (1)

[Scope of utility model registration request] an exhaust turbo supercharger, a plurality of cylinders, exhaust pipes provided in the same number as the cylinders, and an exhaust gas provided in the same number as the superchargers and connecting the exhaust turbine inlet of the supercharger and each exhaust pipe. In an internal combustion engine equipped with a collecting pipe, an exhaust bypass passage is provided in the vicinity of the cylinder outlet of some of the exhaust pipes, and communicates with the atmosphere from the cylinder outlet. A switching valve that opens and closes, and a detection device that is installed in an air supply pipe connecting the blower outlet of the supercharger and the cylinder and that detects the air supply and sends an opening/closing signal for the switching valve. Features an exhaust turbo supercharging device.