JPS5949316A - Scavenging port device - Google Patents

Abstract

PURPOSE:To improve the efficiency of engine, by providing second scavenging ports on the side of a stage preceding the original scavenging ports, and automatically supplying a feed air, increased in temperature resulting from pressurization effected by a supercharger, from the scavenging ports in a manner that the air passes therethrough without any purpose but scavenging. CONSTITUTION:Second scavenging ports 9 are peripherally provided on the cylinder head side, and are communicated with the upstream side of an intercooler 7 through a second feed air pipe 10 and a check valve 11. While the upper end of a piston 3 is passing through the openings of the scavenging ports 9, hot feed air is supplied as scavenging air in a cylinder 1 through the check valve 11. Further, when the piston 3 reaches the bottom dead point, scavenging ports 2 are opened, and thereby pressure of cold feed air blown up in a pressurizing chamber 8 is high. As a result, the supply of the hot feed air from the scavenging ports 9 is stopped by the check valve 11, only cold air is supplied until the scavenging ports 2 are closed, and an engine is shifted in its compression stroke. Thus, hot feed air, remaining in the condition to be pressurized by a supercharger 5, is mainly utilized as a passing-through air for scavenging, resulting in improvement of the efficiency of engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scavenging boat device, particularly to a scavenging boat device for a two-stroke diesel engine.

FIG. 1 shows an outline of a conventional two-stroke diesel engine. That is, in FIG. 1, numeral 1 is a cylinder surrounding a scavenging boat 2, 3 is a piston, 4 is an exhaust valve, 5 is a supercharger mainly driven by the exhaust gas that has passed through the exhaust valve 4, Reference numeral 6 denotes an air supply pipe that guides the supply air pressurized by the supercharger 5 to the scavenging boat 2; 7 an intercooler that is interposed in the middle of the air supply pipe 6 to cool the supply air; 8;
Similarly, it is a pressurizing chamber located close to the scavenging boat 2 in the air supply pipe 6, in which the cooled supply air is repressurized (blow-up) and sent to the scavenging boat 2.

However, in this conventional example, as is well known, scavenging at the end of the explosion-expansion process, so-called through-through air, is carried out only with blown cooling air, so the exhaust temperature decreases and subsequent exhaust heat utilization is reduced. I don't think there will be any disadvantages that will hinder me.

In order to improve these conventional drawbacks, this invention provides a second scavenging boat on the front stage side of the existing scavenging boat, and from this scavenging boat, the air before being cooled by the intercooler is pressurized by the supercharger. The high-temperature supply air is automatically supplied as pure air.

Hereinafter, one embodiment of the scavenging boat device according to the present invention will be described in detail with reference to FIGS. 2 and 3.

FIG. 2 is a schematic explanatory diagram corresponding to FIG. 1 to which this embodiment is applied. In FIG. 2, the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and in this embodiment, a second scavenging boat 9 is installed around the previous side of the conventional scavenging boat 2, that is, near the cylinder head. At the same time, this scavenging boat 9 and the upstream side of the intercooler 7 for supply air v6 are communicated with the second air supply pipe 10 via an Eri check valve 11.

Therefore, in the case of this embodiment, the scavenging action is performed as shown in Kf'i, Figures 3-3. That is, a second scavenging boat 9 is disposed in front of the conventional scavenging boat 2 and close to the cylinder head side, and the scavenging boat 9 is provided with the ink before being cooled by the ink cooler T through the check valve 11. Since hot supply air is supplied, the upper end of the piston 3, which is operated downward during the explosion and expansion process, operates in the same manner as before until it reaches the upper edge of the opening of the scavenging boat 9, as shown in Figure a. However, while the upper end of the piston 3 passes through the entrance of the scavenging boat 9 as shown in the figure, the internal pressure of the cylinder 1 is supplied to the scavenging boat 9 in conjunction with the opening of the exhaust valve 4. Since the hot supply air is lower than the supply pressure, this hot supply air is supplied into the cylinder 1 via the check valve 11 as scavenging air, so-called pass-through air.

Then, when the upper end of the piston 3 passes through the scavenging boat 9.2λ and reaches the bottom dead center as shown in FIG. , and the pressure of the cold supply air that is blown up again in the pressurizing chamber 8 is also high, as is the pressure of the hot supply air that is being supplied to the scavenging boat 9. Since the supply of hot air from the scavenging boat 9 is stopped, there is a flow of air inside the cylinder 1 until the scavenging boat 2 is closed by the piston 3, as shown in FIG. Only cold air is supplied and the compression process begins. In other words, in this way, the hot supply air pressurized by the A feeder 5 is mainly used as the bypass air for scavenging.

As described above in detail, according to the present invention, a second scavenging boat is provided around the front side of the conventional scavenging boat, and the second scavenging boat is provided with supercharging via a check valve. By supplying hot supply air before being cooled by the intercooler from the machine, the exhaust temperature does not drop drastically due to the passing air for scavenging, and the subsequent use of exhaust heat is effective. At the same time, the energy consumption of the intercooler can be reduced, and the engine efficiency can be improved overall.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the outline of a two-stroke diesel engine equipped with a conventional scavenging boat device, and FIG. 2 is a two-stroke diesel engine equipped with a conventional scavenging boat device.
A configuration diagram showing an overview of a cycle diesel engine,
FIGS. 3(a) to 3(d) are explanatory diagrams of the above action. 1. -- Tatami cylinder, 2.9m @ Scavenging boat, 3.
... Piston, 4... Exhaust valve, 5... Nagisa feeder, 6, 10... Air supply pipe, 7... Battle intercouge,
8... Pressure chamber, 11... Check valve Patent applicant Mitsui Engineering & Shipbuilding Co., Ltd. Agent Masaki Yamakawa (and 1 other person)

Claims (1)

[Claims] A supercharger having a cylinder, a piston, and an exhaust valve surrounding a scavenging boat below and driven by exhaust gas; In a two-stroke diesel engine that includes an intercooler interposed in the middle of the air supply pipe, and a pressurization chamber that repressurizes the air supply at a position close to the scavenging boat in the air supply pipe, the engine is located at the front stage of the scavenging boat, on the cylinder head side. A second scavenging boat is disposed around the scavenging boat near the intercooler, and the entire supply air before being cooled by the intercooler can be supplied to the second scavenging boat via a check valve. Scavenging boat equipment.