JPS6233081Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat insulating structure for a fuel supply system in an internal combustion engine, particularly an internal combustion engine with a fuel injection device.

In recent years, technological advances have led to the use of electronically controlled fuel injection systems as a fuel supply means for automobile gasoline engines, replacing the carburetor system.

Particularly in a counterflow internal combustion engine in which an intake manifold and an exhaust manifold are located on the same side, a fuel supply system including intake and fuel pipes directly receives radiant heat from the exhaust system. For this reason, a heat insulating material called a riser packing is provided between the intake manifold and the exhaust manifold, and a heat insulating material called an insulator is provided between the intake manifold and the throttle body to block the propagation of radiant heat to the fuel supply system. things are being done.

However, the insulation effect of the above-mentioned heat insulating material is still not sufficient, and some of the radiant heat is transmitted to the fuel supply system, resulting in boiling of the fuel, which deteriorates the startability of the engine and the fuel supply during operation. A situation occurs.

The present invention has been made to effectively eliminate such inconveniences, and its purpose is to further interpose a blocking plate at the bottom of the insulator interposed between the intake manifold and the throttle body, and to remove the blocking plate. By extending to the branch pipe of the injector and intake manifold, the internal combustion system blocks the propagation of exhaust heat to the fuel supply system, including the intake and fuel piping, suppresses fuel boiling, and prevents deterioration in engine startability. The object of the present invention is to provide a heat insulating structure for a fuel supply system in an engine.

A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

The drawing is a partially cutaway side view of the internal combustion engine.

The engine 1 is mounted so as to be tilted forward in a direction perpendicular to a crankshaft (not shown). In this engine 1, 2 is a cylinder, and a piston 3 is fitted into the cylinder 2 so as to be able to slide up and down, and the piston 3 and the crankshaft are connected by a connecting rod 4.

A cylinder head 5 is fixed to the upper surface of the cylinder 2, and the upper surface of the cylinder head 5 is covered with a cylinder head cover 6. In this way, a combustion chamber S is formed on the upper surface side of the piston 3 in the cylinder 2, and the combustion chamber S is connected to the intake port 7 and the intake pipe 8.
Throttle body 10 via intake manifold 9
The throttle body 10 is in communication with an air cleaner 11. An intake valve 12 for opening and closing the intake port 7 is slidably inserted into the cylinder head 5, and the intake valve 12 is pressed against a valve seat by a spring 13 to close the intake port 7. , overhead cam 1
The tappet 15, which swings in accordance with 4, is connected to the intake valve 12.
is intermittently pushed down, thereby opening and closing the intake port 7 intermittently.

On the other hand, 20 and 30 are fuel injection devices. For example, in the fuel injection device 20, 21 is an injector, and a nozzle 21a forming the tip of the injector 21 faces into the air passage inside the throttle body 10. And this injector 21
is connected to an electronically controlled fuel injection pump (not shown) via fuel piping, a fuel filter, etc. Note that the configuration of the other fuel injection device 30 is the same, so a description thereof will be omitted.

Further, the combustion chamber S is connected to a turbocharger 17 via an exhaust port and an exhaust manifold 16 (not shown).
The exhaust port is connected to cylinder head 5.
The intake valve 12 is intermittently opened and closed by an exhaust valve (not shown) provided in parallel with the intake valve 12.

Incidentally, an insulator 22 is interposed between the throttle body 10 and the intake manifold 9, and a heat shield plate 23 is further interposed on the lower surface side of the insulator 22, and the heat shield plate 23 is connected to the fuel injection device 30. The branch pipe of the injector 31 and the intake manifold 9, that is, the intake pipe 8 is extended.

Also, the intake manifold 9 below the heat shield plate 23
Another heat shield plate 24 is interposed between the turbocharger 17 and the turbocharger 17, and the heat shield plate 24 extends to each branch pipe of the intake manifold 9 and the exhaust manifold 16 as shown.

Therefore, the heat shield plate 23 effectively blocks the propagation of radiant heat from the exhaust manifold 16 side to the fuel supply system including the injector 31, and also prevents the heat from the turbocharger 17, which is heated by exhaust heat, from propagating to the intake system. The propagation is effectively blocked by the heat shield plate 24.
As a result, the occurrence of a situation in which the fuel contained in the fuel supply system boils due to heat from the exhaust system is effectively prevented, and the engine startability and fuel supply during operation are thereby effectively prevented. This prevents a decrease in

As is clear from the above explanation, according to the present invention, a heat shield plate is further installed at the lower part of the insulator interposed between the intake manifold and the throttle body, and extends to the injector and the branch pipe of the intake manifold. It is possible to effectively block the propagation of exhaust heat to the fuel supply system including the fuel supply system, suppress boiling of fuel contained in the fuel supply system, and prevent a decrease in engine startability and fuel supply during operation.

[Brief explanation of drawings]

The drawing is a partially cutaway side view of an internal combustion engine showing an embodiment of the present invention. In the drawing, 8 is the intake pipe, 9 is the intake manifold,
10 is a throttle body, 16 is an exhaust manifold, 17 is a turbocharger, 20 and 30 are fuel injection devices, 21 and 31 are injectors, 22 is an insulator, and 23 and 24 are heat shield plates.

Claims (1)

[Scope of utility model registration request] In an internal combustion engine with a fuel injection device in which an insulator is interposed between an intake manifold and a throttle body, a heat shield plate is further interposed below the insulator, and the heat shield plate is extended to the injector and a branch pipe of the intake manifold. A heat insulating structure for a fuel supply system in an internal combustion engine, characterized by comprising: