JPS61223264A - Fuel jet apparatus of diesel engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises an injection pump driven by an engine;
The present invention relates to a fuel injection device for a diesel engine having a nozzle holder for an injection nozzle that is biased by a spring.

In known devices of this type, the injection pump is driven via a cam of the engine. At that time, the amount of fuel injected is
It may be controlled by an adjustable sloping ridge on the bon plum and an overflow hole in the pump element, or by an overflow valve that is adjustable at the point of opening.

However, in the case of this type of equipment, due to the compression ratio of the fuel,
It has been demonstrated that a certain amount of feed stroke is necessary, that is, it takes a certain amount of time for the nozzle needle to open when the pressure for mixture formation is relatively low. The pressure for mixture formation depends on the construction of the device and on how pretensioning of the spring of the nozzle holder can be achieved. For the same reason, the disadvantage is that the nozzle needle is closed in a manner that is unfavorable for mixture formation.

Since the injection cam is directly driven by the engine, the amount of injection pressure that can be obtained depends on the engine speed. Therefore, especially when the engine speed is low,
The injection pressure is reduced and the mixture formation properties are affected accordingly.

Furthermore, if the engine load is low, 1. Due to the compression ratio of the fuel, the injection pressure increases relatively slowly over time and the injection quantity becomes small, resulting in a low pressure that is unfavorable for mixture formation.

In order to solve this problem, it is known to increase the injection pressure at full load and full speed so that sufficient air-fuel mixture formation characteristics can be obtained even at low loads and low rotational speeds. However, in many cases the drive, which also controls the valve, is overloaded. This results in undesirable loads and, due to insufficient sizing, the engine and associated components may fail. However, this kind of injection device is durable.

It is widely used because of its simple structure and low manufacturing cost.

Furthermore, injection devices are known in which fuel is supplied to the device in front of the injection nozzle via a special high-pressure pump. In this type of device, the injection amount, injection start timing, and injection time are adjusted by opening and closing a nozzle needle that is controlled from the outside.

This operation takes place mechanically, for example via a tilting lever, a push rod, or a suitable control device. The control can be effected by a cam on the camshaft or by electronic control by means of an electro-hydraulic operating mechanism.

The advantage of this type of injection device is that the fuel is optimally injected into the cylinder in a well-formed mixture, regardless of the load and engine speed of the engine.

A disadvantage of so-called mechanically controlled forging devices lies in the complexity of the mechanical drive for operating the nozzle needle, and in particular the complexity of the adjustment mechanism. This is the reason why this type of injector, despite its excellent combustion technology, has not become very popular.

Electronic/hydraulic operation of the injection valve (electronic injection device).

Due to the technical difficulties involved in the high-pressure electro-hydraulic part (which can be overcome by supply pumps) and the high cost of electronic control, it has never been systematically developed. .

SUMMARY OF THE INVENTION The aim of the invention is to improve the known injection devices and to make it possible to easily produce such a device which solves the practical problem and which ensures an increase in the overall pressure level.

In order to achieve the above object, the present invention provides an auxiliary pump as a high-pressure pump that can be driven independently in the fuel supply means for the injection pump, and creates a high pre-pressure in the suction chamber of the injection pump. It is characterized by being able to function.

By providing an auxiliary pump according to the invention.

The overall pressure level of a conventional intermittent injector is increased and the nozzle needle opens and closes at the optimum pressure for combustion. In this case, an improvement is also obtained in terms of mixture formation.
・Additionally, the spring chamber of the nozzle holder of the injection nozzle.

Another improvement is that it can be activated simultaneously by the pressure of the auxiliary pump. This not only changes the opening/closing pressure of the valve through the appropriate action of the spring, but also makes it possible to change the start of injection by controlling the valve opening timing by selecting the preload.

This is particularly important for optimizing the fuel consumption of diesel engines.

Another advantage of the injection device according to the invention is that the pressure energy is supplied externally, i.e. the initiation of the injection process and its subsequent changes depend on a high pressure level, which does not deform the injection cam or the injection pump. - The injection efficiency can be increased without the need to enlarge the cylinder, and therefore the injection time can be shortened to a considerable extent for the purpose of improving engine efficiency. This point is particularly important. Because.

This is because if the working efficiency of the diesel engine is continuously increased by shortening the injection time, the loads on the camshaft, valve drive device, and camshaft drive device will constantly increase.

A further advantage of the invention is that it is only necessary to bring the prepressure by means of an auxiliary pump to the value obtained by the series of high-pressure pumps conventionally used in hydraulic systems.

According to an advantageous embodiment of the invention, the auxiliary pump can be controlled via a regulating device into which a reference input value of the engine can be entered via a counting unit.

Furthermore, the fuel supply pipe for the spring chamber of the nozzle holder of the injection nozzle has a pressure regulating valve that is controlled via a regulating device, to which the reference input value of the engine is input via a counting unit. Can be entered.

To maintain a sufficient temperature level and to circulate the preheated fuel, the fuel supply line for the injection pump can be switched via a multi-way valve and an auxiliary line as a circulation line when the engine is stopped. It is advantageous that

Fruit 1 Yutaka Next, embodiments of the present invention will be described using the accompanying drawings.

In the configuration shown, fuel is supplied from a fuel container 2 to an auxiliary pump 4 via a supply pump 1 and a line 3. The auxiliary pump 4 generates a prepressure on the injection pump 5 and is connected via a line 6 to the suction chamber of the injection pump 5 . injection pump 5
supplies fuel to the injection nozzle 8 via the pressure pipe 7.

The spring chamber of the nozzle holder of the injection nozzle 8 is subjected to the prepressure of the auxiliary pump 4 via a pipe 9 parallel to the pipe 6.

In this embodiment, an auxiliary pump 4 for generating prepressure is used.
is controlled via a regulating device [110] into which a reference input value of the engine can be input via the counting unit 11, for example via the counting unit 11.

The engine speed n, filling amount F, supply air temperature T, cooling water temperature T', and fuel temperature Tel are taken into consideration.

In the pipe 9 for supplying fuel to the spring chamber of the injection nozzle 8, a pressure regulating valve 18 is provided, which can be controlled via a regulating device 12 and at the same time by a counting unit 11. Thereby, the pressure state of the injection nozzle 8 and the prepressure of the injection pump 5 can be hydraulically adjusted.

In the pipes 6 and 3 there is a multi-way valve 13,14 for controlling the auxiliary pipe 15, and in the return pipe 17 for returning fuel from the suction chamber of the injection pump 5 a multi-way valve 16.
is provided to form a ring system in a single-fuel oil engine for circulating preheated fuel when the engine is stopped.

According to such a configuration, it becomes possible to supply fuel to the cylinder via the injection nozzle 8 after the pressure within the pressure pipe 7 reaches a predetermined value. In this case, the pressure regulating valve 18 causes the pressure in the spring chamber of the injection nozzle 8 to be higher than the prepressure in the suction chamber of the injection pump 5 . By appropriately setting the prepressure, it is therefore possible to open and close the nozzle needle of the injection pump 5 at a pressure value that ensures optimal mixture formation characteristics.

[Brief explanation of drawings]

The accompanying drawing is a schematic illustration of an injection device according to the invention. l... Supply pump 2... Fuel container 3.6
．． 9...Fuel supply pipe 4...Auxiliary pump 5,...Injection pump 8...Injection nozzle 10.
12...Adjusting device 11...Counting unit 13, 14.16...Multi-way valve

Claims (5)

[Claims] (1) In a fuel injection device for a diesel engine having an injection pump driven by the engine and a nozzle holder for the injection nozzle biased by a spring, the fuel supply means for the injection pump (5) ( 3, 6),
Auxiliary pump (4) as a high-pressure pump that can be driven independently
1. A fuel injection device characterized in that a high prepressure can be applied to a suction chamber of an injection pump (5). (2) The fuel injection device according to claim 1, characterized in that the spring chamber of the nozzle holder of the injection nozzle (8) can be simultaneously energized by the pressure of the auxiliary pump (4). . (3) The auxiliary pump (4) can input a reference input value of the engine via the counting unit (11) to the adjustment device (10).
) The fuel injection device according to claim 1 or 2, characterized in that it is controllable via a. (4) The fuel supply pipe (9) for the spring chamber of the nozzle holder of the injection nozzle (8) has a pressure regulating valve (18) which is controlled via a regulating device (12); 12) The fuel according to any one of claims 1 to 3, wherein a reference input value of the engine can be inputted via the counting unit (11). Injection device. (5) Fuel supply pipes (3, 6) for injection pump (5)
is switchable via a multi-way valve (13, 14, 16) and an auxiliary pipe (15, 17) as a circulation pipe when the engine is stopped.
4. The fuel injection device according to any one of Items 1 to 4.