阅读说明：本技术 一种柴油发动机低压燃油系统 (Low-pressure fuel system of diesel engine ) 是由 温国生 李棚 于 2020-07-01 设计创作，主要内容包括：本发明涉及一种柴油发动机低压燃油系统,包括输油泵、滤清器、高压油泵、油箱和控制器；所述输油泵的进油口通过第二油管与预滤器连接相通,该预滤器的进油口通过第一油管与所述油箱连接相通；所述输油泵的出油口通过第三油管与滤清器连接相通,该滤清器的出油口通过第四油管与高压油泵的进油口连接相通；还包括设在低压燃油系统中并与所述控制器电连接的电磁三通阀,所述电磁三通阀的第一端通过第五油管与高压油泵的出油口连接相通,所述电磁三通阀的第二端通过第六油管与预滤器回油口连接相通,所述电磁三通阀的第三端通过第七油管与所述油箱连接相通。本发明能够在低压燃油管路无法提高真空度的情况下,实现管路中燃油不随时间而自然回流。(The invention relates to a low-pressure fuel system of a diesel engine, which comprises a fuel delivery pump, a filter, a high-pressure fuel pump, a fuel tank and a controller, wherein the fuel delivery pump is connected with the filter; an oil inlet of the oil transfer pump is communicated with a prefilter through a second oil pipe, and an oil inlet of the prefilter is communicated with the oil tank through a first oil pipe; the oil outlet of the oil delivery pump is communicated with a filter through a third oil pipe, and the oil outlet of the filter is communicated with the oil inlet of the high-pressure oil pump through a fourth oil pipe; the fuel oil system is characterized by further comprising an electromagnetic three-way valve which is arranged in the low-pressure fuel oil system and electrically connected with the controller, a first end of the electromagnetic three-way valve is connected and communicated with an oil outlet of the high-pressure oil pump through a fifth oil pipe, a second end of the electromagnetic three-way valve is connected and communicated with an oil return port of the prefilter through a sixth oil pipe, and a third end of the electromagnetic three-way valve is connected and communicated with the oil tank through a seventh oil pipe. The invention can realize that the fuel in the pipeline does not naturally flow back along with time under the condition that the low-pressure fuel pipeline can not improve the vacuum degree.)

1. A low-pressure fuel system of a diesel engine comprises a fuel delivery pump (10), a filter (30), a high-pressure fuel pump (40), a fuel tank (60) and a controller (70), and is characterized in that:

an oil inlet of the oil transfer pump (10) is communicated with a prefilter (20) through a second oil pipe (2), and an oil inlet of the prefilter is communicated with the oil tank (60) through a first oil pipe (1); an oil outlet of the oil delivery pump (10) is communicated with a filter (30) through a third oil pipe (3), and an oil outlet of the filter is communicated with an oil inlet of a high-pressure oil pump (40) through a fourth oil pipe (4);

the fuel oil system is characterized by further comprising an electromagnetic three-way valve (50) which is arranged in the low-pressure fuel oil system and electrically connected with the controller (70), wherein the first end of the electromagnetic three-way valve (50) is connected and communicated with an oil outlet of the high-pressure oil pump (40) through a fifth oil pipe (5), the second end of the electromagnetic three-way valve (50) is connected and communicated with an oil return opening of the prefilter (20) through a sixth oil pipe (6), and the third end of the electromagnetic three-way valve (50) is connected and communicated with the oil tank (60) through a seventh oil pipe (7).

2. A low pressure fuel system for a diesel engine as set forth in claim 1, wherein: the controller (70) has a first connection wire (71), a second connection wire (72), a third connection wire (73), and a power supply wire (74);

the first connecting wire (71) is electrically connected with the electromagnetic three-way valve (50) and sends a signal to the electromagnetic three-way valve to enable the electromagnetic three-way valve to be in a vertical normally open state;

the second connecting wire (72) is connected with the engine control module (80), and when the controller (70) outputs an action signal to the electromagnetic three-way valve (50), the system action signal is fed back to the engine control module (80);

the third connecting wire (73) is electrically connected with an engine control module (80);

the power cord (74) is connected to a power source and maintains the power supply.

3. A low-pressure fuel system for a diesel engine according to claim 1 or 2, characterized in that: the prefilter (20) has the function of a hand pump.

Technical Field

The invention relates to fuel pipeline arrangement of a diesel engine, in particular to a low-pressure fuel system of the diesel engine. The method is particularly suitable for high-power diesel engines limited by arrangement conditions.

Background

In the existing low-pressure fuel pipeline arrangement of the engine, along with the increase of the power of the engine, the pipe diameter of a system can be increased, and the problem that the starting is difficult due to the fact that an oil inlet pipe naturally runs empty when the engine is stopped can be solved, and the normal use of a client terminal can be influenced seriously. Under the condition that the vacuum degree cannot be improved, in order to realize that fuel oil in a pipeline does not naturally flow back along with time, the common method comprises the following steps:

firstly, a check valve is additionally arranged at an oil inlet; but the oil inlet resistance is increased, the oil supply is obstructed in the starting or bottom rotating speed stage of the engine, and if the check valve is blocked, the engine cannot be normally used;

secondly, when an oil path is arranged, a relay oil tank is additionally arranged as required; but can not satisfy specific requirements in every application occasion, and the addition of the relay oil tank can also increase a plurality of pipeline accessories, increase the cost and cause difficult management.

Therefore, additional approaches to address this problem need to be explored.

CN208651012U discloses a "low-pressure fuel pipeline for diesel engine", which includes a double U-shaped oil return pipe, the double U-shaped oil return pipe includes a high-pressure oil rail oil return connection pipe and an oil injector oil return connection pipe which are located at the upper portion, a high-pressure oil rail and oil injector oil return manifold which are located at the middle portion, and a high-pressure oil pump oil return connection pipe and a total oil return connection pipe which are located at the lower portion, the lower ends of the high-pressure oil rail oil return connection pipe and the oil injector oil return connection pipe are connected with the upper end of the high-pressure oil rail and the oil injector oil return manifold through a first three-way joint, and the lower ends of the high-pressure oil rail and the oil injector oil return manifold are connected with the upper ends of the high-pressure oil pump oil return connection pipe and the total oil return connection pipe through a second three-way joint. The pressure limiting valve can replace the function of the pressure limiting valve, the fuel pump is guaranteed to be full of fuel when not in work, and the pressure limiting valve is low in cost and high in reliability.

CN106870224A discloses a low-pressure oil circuit system for a diesel engine, which comprises a first oil inlet tee joint, wherein an oil inlet of the first oil inlet tee joint is connected with an oil inlet pipe, one oil outlet of the first oil inlet tee joint is connected with an oil inlet pipe of a manual pump, and the other oil outlet of the first oil inlet tee joint is connected with an oil inlet pipe of a fuel delivery pump; an oil outlet port of the oil inlet pipe of the manual pump is connected with an oil inlet of the manual pump, an oil outlet of the manual pump is hermetically connected with one end of the oil outlet pipe of the manual pump, and the other end of the oil outlet pipe of the manual pump is connected with a second oil inlet tee; the oil inlet pipe of the oil transfer pump is connected with the oil inlet of the oil transfer pump, the oil transfer pump is integrated on the high-pressure oil pump, the oil outlet of the oil transfer pump is connected with the oil outlet pipe of the oil transfer pump, and the oil outlet pipe of the oil transfer pump is connected with the second oil inlet tee joint. The low-pressure oil way system has better oil supply performance, and meanwhile, the modularized design can be matched with the application of different machine types.

Needless to say, the technical solutions disclosed in the above patent documents are all useful attempts in the technical field.

Disclosure of Invention

The invention aims to provide a low-pressure fuel system of a diesel engine, which can realize that fuel in a pipeline does not naturally flow back along with time under the condition that a low-pressure fuel pipeline cannot improve the vacuum degree.

The invention relates to a low-pressure fuel system of a diesel engine, which comprises a fuel delivery pump, a filter, a high-pressure fuel pump, a fuel tank and a controller, and is characterized in that:

an oil inlet of the oil transfer pump is communicated with a prefilter through a second oil pipe, and an oil inlet of the prefilter is communicated with the oil tank through a first oil pipe; the oil outlet of the oil delivery pump is communicated with a filter through a third oil pipe, and the oil outlet of the filter is communicated with the oil inlet of the high-pressure oil pump through a fourth oil pipe;

the fuel oil system is characterized by further comprising an electromagnetic three-way valve which is arranged in the low-pressure fuel oil system and electrically connected with the controller, a first end of the electromagnetic three-way valve is connected and communicated with an oil outlet of the high-pressure oil pump through a fifth oil pipe, a second end of the electromagnetic three-way valve is connected and communicated with an oil return port of the prefilter through a sixth oil pipe, and a third end of the electromagnetic three-way valve is connected and communicated with the oil tank through a seventh oil pipe.

Further, the controller has a first connection wire, a second connection wire, a third connection wire, and a power supply line;

the first connecting wire is electrically connected with the electromagnetic three-way valve and sends a signal to the electromagnetic three-way valve to enable the electromagnetic three-way valve to be in a vertical normally open state;

the second connecting wire is connected with the engine control module, and when the controller outputs an action signal to the electromagnetic three-way valve, the controller also feeds back a system action signal to the engine control module;

the third connecting wire is electrically connected with the engine control module;

the power cord is connected with a power supply and keeps the power supply.

Further, the prefilter has a hand pump function.

The invention has the beneficial technical effects

Because the problem is solved from the engine, the natural backflow of the fuel in the pipeline can be realized without time under the condition that the vacuum degree of the low-pressure fuel pipeline can not be improved, the specific requirements can be met in application occasions, and the cost and the management difficulty are reduced;

because the prefilter with the hand pump function is additionally arranged in the fuel system, the situation that the high-power diesel engine cannot be started smoothly due to natural air flowing of an oil inlet pipeline caused by the fact that the high-power diesel engine does not work and is not started within a certain time can be effectively avoided. The prefilter is an aid to the manual emptying of the fuel line.

Because the electromagnetic three-way valve is additionally arranged in the fuel system, the switching of the oil return pipe can be realized under the control of the controller, and the surplus storage in the prefilter is supplemented by the oil return, thereby achieving the system effect.

Drawings

Fig. 1 is a schematic structural view of the present invention.

In the figure:

1-a first oil pipe, 2-a second oil pipe, 3-a third oil pipe, 4-a fourth oil pipe, 5-a fifth oil pipe, 6-a sixth oil pipe, and 7-a seventh oil pipe;

10-oil delivery pump, 20-prefilter, 30-filter, 40-high-pressure oil pump, 50-electromagnetic three-way valve, 60-oil tank,

70-controller, 71-first connecting wire, 72-second connecting wire, 73-third connecting wire, 74-power line;

80-engine control module.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1, a low-pressure fuel system of a diesel engine includes a fuel delivery pump 10, a filter 30, a high-pressure fuel pump 40, a fuel tank 60, and a controller 70, and is characterized in that:

an oil inlet of the oil transfer pump 10 is communicated with a prefilter 20 through a second oil pipe 2, and an oil inlet of the prefilter is communicated with the oil tank 60 through a first oil pipe 1; an oil outlet of the oil delivery pump 10 is communicated with a filter 30 through a third oil pipe 3, and an oil outlet of the filter is communicated with an oil inlet of a high-pressure oil pump 40 through a fourth oil pipe 4; the prefilter is adopted and used as a relay function, and the limitation of places and specific requirements is avoided.

The fuel oil system further comprises an electromagnetic three-way valve 50 which is arranged in the low-pressure fuel oil system and electrically connected with the controller 70, a first end of the electromagnetic three-way valve 50 is connected and communicated with an oil outlet of the high-pressure oil pump 40 through a fifth oil pipe 5, a second end of the electromagnetic three-way valve 50 is connected and communicated with an oil return port of the pre-filter 20 through a sixth oil pipe 6, and a third end of the electromagnetic three-way valve 50 is connected and communicated with the oil tank 60 through a seventh oil pipe 7.

The controller 70 has a first connection wire 71, a second connection wire 72, a third connection wire 73, and a power supply wire 74;

the first connecting wire 71 is electrically connected with the electromagnetic three-way valve 50 and sends a signal to the electromagnetic three-way valve to enable the electromagnetic three-way valve to be in a vertical normally open state, so that return oil is enabled to be directly communicated to an oil tank;

the second connection wire 72 is connected to the engine control module 80, and when the controller 70 outputs an actuation signal to the three-way solenoid valve 50, a system actuation signal is also fed back to the engine control module 80. The function is that when the engine control module enters a debugging state, manual adjustment enables the system to act, and the debugging process of the engine is shortened. When the system is used, a system function indicating lamp can be arranged on the unit control box, and system indication is carried out on the control part. By means of this indication, the commissioning emptying process can be shortened by switching the system on in parallel during partial commissioning. Let the indication of the system play a practical role.

The third connecting wire 73 is electrically connected to the engine control module 80. When the engine is in a running state, a 5V positive pole signal is input to the controller, and the controller receives the signal, so that the system does not act; when the running state of the engine is changed, the signal input is interrupted, and the controller controls the electromagnetic three-way valve to act, so that the preset requirement of the system is met.

The power cord 74 is connected to a power source and maintains the power supply.

The controller 70 works on the principle: when the control module engine operation signal (0-5V) and the signal (0-5V) given by the engine speed sensor are input through the third connecting wire 73, the first connecting wire 71 does not output actually when the input signal is available, and the electromagnetic three-way valve 50 is in a vertical normally open state. When the engine is stopped, the control module engine operation signal in the input signal is immediately cut off, and the voltage value of the signal of the rotating speed sensor is reduced along with the reduction of the rotating speed, at the moment, the controller takes any one of the signals and connects the internal circuit, and continuous current is output to the electromagnetic three-way valve 50 through the first connecting wire 71, so that the electromagnetic three-way valve 50 is kept to be switched. The controller 70 sends a command to the electromagnetic three-way valve 50, and at the same time, transmits an operation feedback signal to the controller via the second connection electric wire 72.

Because the low-pressure fuel system also has a cooling function for the fuel delivery pump, the actual fuel supply amount is several times of that of each circulation oil path of the high-pressure fuel pump 40, and the redundant supplied fuel returns to the fuel tank 60 through the fifth fuel pipe 5, the electromagnetic three-way valve 50 and the seventh fuel pipe 7. In the whole engine operation process, the electromagnetic three-way valve 50 is in a vertical normally open state by receiving a signal transmitted by the first connecting wire 71 of the controller 70, and oil return is ensured to be directly communicated to the oil tank 60. Wherein the controller 70 is kept supplied with power from the power line 74, and the third connection wire 73 is kept in the engine signal state input (the maintenance panel operation signal, the rotation speed sensor signal are input).

The prefilter 20 has the function of a hand pump. The hand pump is integrated on the prefilter base, so that accessories in a pipeline are reduced, leakage points are reduced, and the vacuum degree of the system can be better maintained. The prefilter is a diesel prefilter assembly disclosed in CN 200949497.

The prefilter with the hand pump function only plays a role in manually pumping oil to be emptied when the engine is debugged for the first time or the maintenance is carried out in the middle of the engine and the fuel oil pipeline needs to be emptied manually.

When the engine normally works, fuel oil in the oil tank 60 reaches the high-pressure oil pump 40 through the first oil pipe 1, the prefilter 20, the second oil pipe 2, the fuel oil pump 10, the third oil pipe 3, the filter 30 and the fourth oil pipe 4 due to self-priming of the fuel oil pump 10, and the fuel oil is supplied to the equipment to normally run through the high-pressure oil pump.

When the engine is stopped, the controller 70 receives a stop signal, and executes an oil path reversing instruction to the electromagnetic three-way valve 50, so that the seventh oil pipe 7 is cut off and the sixth oil pipe 6 is connected. The return oil will then be supplied directly to the prefilter 20 via the three-way solenoid valve 50 and will not return directly to the oil tank 60. During the standby period after the engine is stopped, the fuel in the pipeline can be controlled to fall back by the self-sealing performance because the prefilter 20 is close to the fuel tank 60 and is at a position with a lower liquid level difference. However, the filter 30 and the fourth oil pipe 4 near the oil inlet pipe cannot achieve the situation of no backflow due to large liquid level difference and long pipelines, so the function of the relay oil tank is ensured by the liquid level maintenance of the prefilter 20, and the liquid level is maintained by the fifth oil pipe 5, the electromagnetic three-way valve 50, the sixth oil pipe 6 and the fuel oil stored in the pipeline during shutdown; the fifth oil pipe 5 is supplied with fuel preferentially to the prefilter 20 due to a large level difference, so that the prefilter functions as a relay tank. The pipeline of the low-pressure fuel system is kept full of fuel, so that real-time self-starting is realized under the condition of unattended equipment. Thereby saving cost and equipment field.