阅读说明：本技术 车辆、直喷汽油机的燃油供给系统及燃油供给方法 (Fuel supply system and fuel supply method for vehicle and direct injection gasoline engine ) 是由 姚卓 于 2019-04-12 设计创作，主要内容包括：本发明公开了一种车辆、直喷汽油机的燃油供给系统及燃油供给方法,该燃油供给系统包括燃油箱和燃油预热装置；所述燃油预热装置设置在所述燃油箱的出油口与所述直喷汽油机的喷油器之间,使燃油经所述燃油预热装置预热后喷入所述直喷汽油机的气缸。该燃油供给系统可以提高直喷汽油机的效率、降低直喷汽油机的成本,并且可以规避较多的燃油喷射到气缸壁上致使直喷汽油机的润滑性能和排放性能变差的问题,使直喷汽油机具有较好的运行可靠性和排放性能。(The invention discloses a fuel supply system and a fuel supply method of a vehicle and a direct injection gasoline engine, wherein the fuel supply system comprises a fuel tank and a fuel preheating device; the fuel preheating device is arranged between the fuel outlet of the fuel tank and the fuel injector of the gasoline direct injection engine, so that fuel is preheated by the fuel preheating device and then injected into the cylinder of the gasoline direct injection engine. The fuel supply system can improve the efficiency of the direct injection gasoline engine, reduce the cost of the direct injection gasoline engine, and avoid the problem that the lubrication performance and the emission performance of the direct injection gasoline engine are poor due to the fact that more fuel is injected to the cylinder wall, so that the direct injection gasoline engine has better operation reliability and emission performance.)

1. A fuel supply system of a direct injection gasoline engine, characterized in that the fuel supply system comprises a fuel tank (2) and a fuel preheating device;

the fuel preheating device is arranged between the oil outlet of the fuel tank (2) and the oil injector of the gasoline direct injection engine (1), so that fuel is sprayed into the cylinder of the gasoline direct injection engine (1) after the fuel preheating device preheats.

2. A fuel supply system according to claim 1, characterized in that the fuel preheating device comprises an electric heater (3) and a battery (4) for supplying power to the electric heater (3).

3. A fuel supply system according to claim 2, characterized in that the electric heater (3) is arranged close to the fuel injector or integrated with the fuel injector.

4. A fuel supply system according to any one of claims 2-3, characterized in that the fuel preheating device further comprises a heat exchanger (5), the heat exchanger (5) comprising a first inlet (51) and a first outlet (52) in communication with each other and a second inlet (53) and a second outlet (54) in communication with each other; the first inlet (51) is communicated with the fuel tank (2), and the first outlet (52) is communicated with the fuel injector; the second inlet (53) communicates with a cooling water outlet (12) of the gasoline direct injection engine (1), and the second outlet (54) communicates with a cooling water inlet (11) of the gasoline direct injection engine (1).

5. A fuel supply method of a fuel supply system according to claim 4, characterized in that the fuel supply method is: when the gasoline direct injection engine (1) is in a cold start stage, starting the electric heater (3); when the direct injection gasoline engine (1) is in the heat engine phase, the electric heater (3) is switched off.

6. Vehicle comprising a gasoline direct injection engine (1), characterized in that the gasoline direct injection engine (1) is provided with a fuel supply system according to any one of claims 1 to 4.

Technical Field

The invention relates to the technical field of fuel supply, in particular to a fuel supply system and a fuel supply method of a direct injection gasoline engine.

Background

At present, a fuel supply system of a direct injection gasoline engine generally sets a higher fuel injection pressure, and improves fuel atomization performance through high-pressure injection so as to achieve the purpose of improving the efficiency of the direct injection gasoline engine.

However, in practice, it has been found that setting a higher fuel injection pressure has the following two disadvantages:

on one hand, the requirement on a fuel injection system of a direct injection gasoline engine is higher, and the cost of the direct injection gasoline engine is increased;

on the other hand, the penetration distance of the oil mist is increased, so that more fuel is injected to the cylinder wall of the direct injection gasoline engine, which causes the dilution of the engine oil to increase friction, thereby affecting the operational reliability and the service life of the direct injection gasoline engine, and also causing the deterioration of the emission performance of the direct injection gasoline engine.

In view of the above, it is a technical problem to be solved by those skilled in the art to develop a fuel supply system for a direct injection gasoline engine, so as to improve fuel atomization performance and avoid the above drawbacks.

Disclosure of Invention

In order to solve the technical problem, the invention provides a fuel supply system of a direct injection gasoline engine, which comprises a fuel tank and a fuel preheating device;

the fuel preheating device is arranged between the fuel outlet of the fuel tank and the fuel injector of the gasoline direct injection engine, so that fuel is preheated by the fuel preheating device and then injected into the cylinder of the gasoline direct injection engine.

Experiments show that the diameter of oil mist liquid drops can be obviously reduced by preheating the fuel oil and then injecting the fuel oil, the penetration distance of the oil mist can be obviously reduced, the quantity of the oil mist liquid drops with large diameters can be obviously reduced, and most of the oil mist liquid drops are small-diameter oil mist liquid drops.

The smaller the diameter of the oil mist droplets is, the better the evaporation of gasoline is and the more sufficient the combustion is, so the fuel supply system provided by the invention can improve the efficiency of the direct injection gasoline engine. In addition, compared with the prior art that the efficiency of the direct injection gasoline engine is improved by increasing the fuel injection pressure, the fuel supply system provided by the invention has lower requirements on the fuel injection system of the direct injection gasoline engine, and the direct injection gasoline engine can select the fuel injection system with lower injection pressure, so that the cost of the direct injection gasoline engine can be reduced.

In addition, the small oil mist liquid drops are small in momentum and difficult to spray to the cylinder wall, and the oil mist is small in penetration distance and difficult to spray to the cylinder wall due to the fact that the spraying pressure is low. Therefore, the fuel supply system provided by the invention can avoid the problem that the lubricating performance and the emission performance of the direct injection gasoline engine are poor due to more fuel being injected to the cylinder wall, so that the direct injection gasoline engine has better operation reliability and emission performance.

Optionally, the fuel preheating device comprises an electric heater and a storage battery for supplying power to the electric heater.

Optionally, the electric heater is arranged close to or integrated with the fuel injector.

Optionally, the fuel oil preheating device further comprises a heat exchanger, wherein the heat exchanger comprises a first inlet and a first outlet which are communicated with each other and a second inlet and a second outlet which are communicated with each other; the first inlet is communicated with the fuel tank, and the first outlet is communicated with the fuel injector; the second inlet communicates with a cooling water outlet of the gasoline direct injection engine, and the second outlet communicates with a cooling water inlet of the gasoline direct injection engine.

The invention also provides a fuel supply method of the fuel supply system, which comprises the following steps: when the gasoline direct injection engine is in a cold start stage, starting the electric heater; and when the direct injection gasoline engine is in a heat engine stage, the electric heater is closed.

The invention also provides a vehicle including a gasoline direct injection engine equipped with the fuel supply system described in any one of the above.

Drawings

FIG. 1 is a simplified diagram of one embodiment of a fuel delivery system provided by the present invention;

FIG. 2 is a two-dimensional graph of fuel temperature, penetration distance of oil mist and diameter of mist droplets of oil mist obtained by experiment when fuel injection pressure is 10 MPa;

FIG. 3a is a graph showing the distribution of the diameters of mist droplets obtained by an experiment when the fuel injection pressure is 10MPa and the fuel temperature is 20 ℃;

FIG. 3b is a graph showing the experimental distribution of the diameter of the mist droplets at a fuel injection pressure of 10MPa and a fuel temperature of 50 deg.C;

fig. 3c is a graph showing the distribution of the diameters of the mist droplets of the oil mist at the fuel injection pressure of 10MPa and the fuel temperature of 80 c, which were obtained by the experiment.

Wherein the reference numerals in fig. 1 are explained as follows:

1 direct injection gasoline engine, 11 cooling water inlet, 12 cooling water outlet, 2 fuel tank, 3 electric heater, 4 accumulator, 5 heat exchanger, 51 first inlet, 52 first outlet, 53 second inlet and 54 second outlet.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the technical solutions of the present invention are further described in detail below with reference to the accompanying drawings and the detailed description.

Referring to fig. 1, fig. 1 is a schematic diagram of an embodiment of a fuel supply system according to the present invention.

As shown in fig. 1, the fuel supply system of a direct injection gasoline engine according to the present invention includes: a fuel tank 2 and a fuel preheating device. The fuel preheating device is arranged between the oil outlet of the fuel tank 2 and the oil injector of the direct injection gasoline engine 1, so that the fuel is preheated by the fuel preheating device and then is injected into the cylinder of the direct injection gasoline engine 1.

In order to verify the effect of the fuel supply system, a corresponding experiment system is designed, the experiment system adopts a constant volume combustion bomb and a fuel injector to simulate a direct injection gasoline engine, the fuel injector is vertically arranged at the top of the constant volume combustion bomb, a heating ring is sleeved on the fuel injector, and the constant volume combustion bomb is provided with a quartz window. A high-pressure nitrogen cylinder, a piston type energy accumulator and a high-pressure oil pipe are adopted to supply oil and gas to a combustion cavity of the constant-volume combustion bomb. A high-energy xenon lamp with adjustable brightness is used as an experimental light source. The oil mist is photographed by a high-speed camera through a quartz window and the image is transmitted to a computing unit.

During the experiment, a certain fuel oil injection pressure is kept, the heating temperature of the heating ring is adjusted, the fuel oil is preheated to different temperatures, the injection states of the fuel oil at different temperatures are respectively shot, and the penetration distance of the oil mist and the diameter of oil mist liquid drops are measured according to the shot images. Specifically, the diameter of the oil mist droplets is the sauter mean diameter, which is the diameter corresponding to a cube converted into an isovolumetric sphere.

Referring to fig. 2, fig. 3a, fig. 3b and fig. 3c, fig. 2 is a two-dimensional graph of the temperature of the fuel, the penetration distance of the oil mist and the diameter of the oil mist droplets when the fuel injection pressure is 10 MPa; FIG. 3a is a graph showing the distribution of the diameters of mist droplets obtained by an experiment when the fuel injection pressure is 10MPa and the fuel temperature is 20 ℃; FIG. 3b is a graph showing the experimental distribution of the diameter of the mist droplets at a fuel injection pressure of 10MPa and a fuel temperature of 50 deg.C; fig. 3c is a graph showing the distribution of the diameters of the oil mist droplets when the fuel injection pressure is 10MPa and the fuel temperature is 80 c, which are obtained by experiments.

As can be seen from fig. 2, the oil mist droplets can be significantly reduced in diameter and the penetration distance of the oil mist can be significantly reduced by preheating the oil and then injecting the preheated oil. 3a-3c, the amount of large mist droplets can be significantly reduced by preheating the fuel and then injecting the preheated fuel, so that most mist droplets are small mist droplets.

The smaller the diameter of the oil mist droplets is, the better the evaporation of gasoline is and the more sufficient the combustion is, so the fuel supply system provided by the invention can improve the efficiency of the direct injection gasoline engine. In addition, compared with the prior art that the efficiency of the direct injection gasoline engine is improved by increasing the fuel injection pressure, the fuel supply system provided by the invention has lower requirements on the fuel injection system of the direct injection gasoline engine, and the fuel injection system with lower injection pressure can be selected for the direct injection gasoline engine, so that the cost of the direct injection gasoline engine can be reduced.

In addition, because the momentum of the small-diameter oil mist liquid drops is small, the small-diameter oil mist liquid drops are difficult to spray to the cylinder wall, and the oil mist spraying pressure is low, the penetration distance of the oil mist is small, and the oil mist is difficult to spray to the cylinder wall. Therefore, the fuel supply system provided by the invention can avoid the problem that the lubricating performance and the emission performance of the direct injection gasoline engine are poor due to more fuel being injected to the cylinder wall, so that the direct injection gasoline engine has better operation reliability and emission performance.

Specifically, as shown in fig. 1, the fuel preheating device includes an electric heater 3 and a battery 4 that supplies power to the electric heater 3. Preferably, the electric heater 3 is arranged close to the fuel injector or integrated with the fuel injector into a whole, so that the preheated fuel can participate in combustion as soon as possible, and the problem that the temperature of the preheated fuel is reduced when the preheated fuel reaches the fuel injector due to the fact that the electric heater is far away from the fuel injector is solved.

Further, as shown in fig. 2, the fuel preheating device further includes a heat exchanger 5, and the heat exchanger 5 includes a first inlet 51 and a first outlet 52 communicating with each other, and a second inlet 53 and a second outlet 54 communicating with each other.

Wherein the first inlet 51 communicates with the fuel tank 2 and the first outlet 52 communicates with the fuel injector. The second inlet 53 communicates with the cooling water outlet 12 of the direct injection gasoline engine 1, and the second outlet 54 communicates with the cooling water inlet 11 of the direct injection gasoline engine 1. With this arrangement, the cooling water discharged from the direct injection gasoline engine 1 is used to preheat the fuel, thereby reducing the power consumption of the electric heater 3.

In a state where the electric heater 3 and the heat exchanger 5 are provided at the same time, the following fuel supply method may be adopted:

when the direct injection gasoline engine 1 is in a cold start stage, starting the electric heater 3, and preheating fuel by adopting the electric heater 3;

when the direct injection gasoline engine 1 is in the warm-up stage, the electric heater 3 is turned off, and the fuel is preheated using the cooling water flowing through the heat exchanger 5. In the heat engine stage, the cooling water discharged from the direct injection gasoline engine 1 has higher heat, and the preheating requirement of fuel can be fully met. Of course, if the fuel oil can not be preheated only by the cooling water, the electric heater 3 can be started together, so that the two heating modes are parallel.

Further, the invention provides a vehicle including a direct injection gasoline engine provided with the above fuel supply system, and the above fuel supply method may be adopted.

The fuel supply system and the fuel supply method of the vehicle, the direct injection gasoline engine provided by the present invention have been described in detail. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.