JPH0538336U - Direct injection diesel engine - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention relates to a direct-injection diesel engine mounted on automobiles, etc., and more specifically, a direct-injection diesel engine capable of reducing the top clearance of the piston as much as possible. Regarding In a direct injection diesel engine in which a cavity forming a part of a combustion chamber is formed in a piston head, a thickness of 0.60 to 0.60 is formed on a lower surface of a cylinder head facing the piston head. A 1.00 mm soft laminator plate is sandwiched between the cylinder head and the cylinder liner, avoiding the positions of the intake / exhaust valve port and the piston / cavity, and the soft laminator is also used. The plate is made of a composite material in which the cylinder head side is a flat base layer and the piston head side is an elastic layer having a corrugated cross section.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a direct-injection diesel engine, and more particularly to a direct-injection diesel engine capable of reducing the top clearance of a piston as much as possible.

[0002]

[Prior Art]

 In a conventional direct injection diesel engine, a cavity that forms a part of the combustion chamber is formed in the piston head, and the inertia force of the piston causes interference between the piston head and the cylinder head that faces the piston head. In order to prevent the occurrence of the accident, a clearance is set up with the cylinder head.

[0003]

[Problems to be solved by the device]

 On the other hand, in order to improve the black smoke and patty killer rate of the diesel engine, it is important to strengthen the air flow in order to promote the mixing with the fuel, and for that purpose, the above-mentioned clearance is made as close to zero as possible, It has been a subject to increase the flow of skipping and to enhance the air flow in the cavity.

[0004]

[Means for Solving the Problems]

 In the direct injection type diesel engine which is the premise of claim 1, in the direct injection type diesel engine in which the cavity forming a part of the combustion chamber is formed in the piston head as described above. On the lower surface of the cylinder head facing the head, a soft laminate plate having a thickness of 0.60 to 1.00 mm is provided to avoid the position of the intake / exhaust valve and the piston / cavity position, It is sandwiched between the head and the cylinder liner.

In the direct injection type diesel engine which is the premise of claim 2, the soft laminate plate according to claim 1 is composed of a composite material including a flat base layer and an elastic layer having a corrugated cross section. Is.

[0006]

[Action]

 In the direct injection diesel engine according to claim 1, when the piston reaches the top dead center with the operation of the direct injection diesel engine, the cylinder head is not interfered with, and the soft engine The laminar plate narrows the top clearance as much as possible, which enhances the swash flow and improves the mixing of the fuel spray.

According to another aspect of the present invention, there is provided a direct injection type diesel engine, wherein a carbon is formed in a concave portion of the elastic layer having a corrugated cross section of the soft laminator plate as the operating time of the direct injection type diesel engine elapses. Adheres to the surface, which makes it possible to bring the top clearance to substantially zero.

[0008]

【Example】

 Next, the invention will be described with reference to the embodiment shown in FIGS. 1 is a vertical sectional view of a part of a piston and a cylinder of a direct injection type diesel engine, and FIG. 2 is a sectional view taken along the line AA of FIG.

The cylinder head 1 is mounted and fixed on the cylinder block 2, and the cylinder liner 3 is fitted in the bore of the cylinder block 2. It is well known that the piston 4 has piston rings such as a top ring 5 mounted on its peripheral portion, and reciprocates while sliding these piston rings on the cylinder liner 3.

The piston head 6 of the piston 4 is formed with a cavity 7 forming a part of a combustion chamber. The injection nozzle 8 is attached to the cylinder head 1 so that its tip faces the cavity 7 of the piston 4 at the top dead center. The cylinder head 1 is also provided with intake and exhaust valve ports 9 and 10.

In this invention, a soft laminar plate 11 is attached to the lower surface of the cylinder head 1 so as to be sandwiched between the cylinder head 1 and the cylinder liner 3, In this case, the soft laminator plate 11 is provided with a cutting portion as shown in FIG. 12, 13, 14 are provided.

As shown in FIG. 3, the soft laminate plate 11 is made of a composite material of a flat base layer 15 and a corrugated elastic layer 16, and the base layer 15 is made into a cylinder head 1. The thickness t is set to 0.60 to 1.00 mm as it is mounted toward the side.

The thickness of the soft laminate plate 11 is set in the above range because the clearance limit of the medium-sized diesel engine (bore diameter 100 to 125 mm) is 0.60 mm and the large diesel engine is large. It is empirically based on the finding that the clearance limit of (bore diameter 125 to 150 mm) is about 1.00 mm as a dynamic limit.

With the operation of the direct injection diesel engine, the piston 4 reciprocates along the cylinder liner 3 and comes closest to the cylinder head 1 at its top dead center. Since the soft laminate plate 11 is interposed between the piston head 6 and the cylinder head 1, the piston head 6 and the cylinder head 1 do not interfere with each other, and the top head Clearance can be reduced as much as possible.

Moreover, with the progress of the operation of the diesel engine, the carbon adheres to the concave portion of the elastic layer 16 of the soft laminate plate 11 to close the concave portion, and finally the top clearance is substantially formed. As a result, the air flow in the cavity 7 of the piston 4 is enhanced and the mixing with the fuel spray is improved, so that the black smoke and the particulate rate can be improved. The relationship is shown in FIG.

[0016]

[Effect of the device]

 According to the direct injection diesel engine of the above structure of the present invention, the top clearance at the top dead center of the piston can be made substantially zero without causing the interference between the piston head and the cylinder head. Since it is possible, by increasing the skip flow and increasing the air flow in the cavities, the mixing with the fuel spray is improved, which contributes to the black smoke of the diesel engine and the improvement of the fuel rate. There is a great deal.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a piston and a part of a cylinder of a direct injection type diesel engine of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a side view of the soft laminator plate.

FIG. 4 is a graph showing the relationship between the operation time of the diesel engine, the air flow energy, and the amount of black smoke produced.

[Explanation of symbols]

 1 Cylinder head 3 Cylinder block 4 Piston 6 Piston head 7 Cavity 9,10 Intake / exhaust valve port 11 Soft laminate 15 Base layer 16 Elastic layer

Claims (2)

[Scope of utility model registration request] 1. In a direct injection diesel engine in which a cavity forming a part of a combustion chamber is formed in a piston head, a lower surface of a cylinder head facing the piston head has a thickness of 0. 60-1.00 mm
A direct injection diesel engine in which the soft laminator plate is sandwiched between the cylinder head and the cylinder liner while avoiding the positions of the intake / exhaust valve port and the piston / cavity. 2. The soft laminator plate is made of a composite material in which the cylinder head side is a flat base layer and the piston head side is an elastic layer having a corrugated cross section. Direct injection diesel engine.