HRP960006A2 - Pneumatic system of direct fuel injection into two-stroke otto engines - Google Patents

Description

The field of technology

The subject of the invention is a pneumatic system for direct fuel injection into two-stroke Otto engines.

According to the international classification of patents, the invention belongs to the field of……….The classification code is………

Technical problem

The invention solved these technical problems:

- flushing the engine cylinder with air and not with a fuel mixture,

- fuel is injected directly into the engine cylinder,

- the fuel supply is provided by a pneumatic differential diaphragm pump, for the operation of which a cyclic change of the pre-suction and pre-compression pressures of the air in the engine housing is used,

- fuel dosing is achieved by adequate displacement of the pump membrane, which is proportional to the change in air pressure in the engine housing.

State of the art

Existing fuel injection systems were developed mainly for four-stroke Otto engines and for Diesel engines. Two-stroke Otto engines were almost completely neglected in this segment of development.

It is known that in the operation process of two-stroke Otto engines, the basic technical problem is cylinder flushing. It is the phase of the process in which there is direct contact and mixing of the incoming medium (fuel mixture) and the outgoing medium - (combustion gases).

The consequences of this are numerous and negative, namely:

- increased fuel consumption,

- reduced engine power,

- impure exhaust gases,

- reduced use of the engine, etc.

There are many attempts and a number of well-known constructions in the form of pistons, cylinder channels, various flaps and the like, which only alleviate the problem of direct media contact, but do not solve it.

Fuel injection systems in the intake line of the engine, modeled on four-stroke Otto engines, also do not solve the problem.

Two-stroke Diesel engines solve the flushing problem so that the incoming medium is clean air, so by precharging it, complete flushing is achieved with the loss of some air.

Images and callsigns

Figure 1.- Schematic representation of the pneumatic system of direct fuel injection into two-stroke Otto engines

The call signs in the picture are:

1. cylinder

2nd clip

3. accelerator valve

4. housing

5. crankshaft

6. connecting hole

7. valve

8. pump

9. elastic membrane

10. intake valve

11. workspace

12. connecting rod

13. large tubular bellows

14. small tubular bellows

15. pressure valve

16. pipe

17. bimetallic spring

18. nozzle

19. pin

20. spring

21. injection valve

Description of the solution

From the described state of the art, it can be seen that the mentioned technical problem is solved if the cylinder is flushed with clean air and if the fuel is injected directly into the cylinder (1) of the engine at the beginning of the compression cycle, and the fuel mixture is ignited by the electric spark of the spark plug.

A specific phase in the operation of most two-stroke engines is pre-suction and pre-compression of the inlet medium in the housing (4). For one revolution of the crankshaft (5), the piston (2) makes two strokes through the cylinder (1), so the pressure of the medium changes in the housing (4). from underpressure to overpressure. This cyclic pressure change is used to operate the pneumatic differential diaphragm pump (8).

The pump (8) is attached to the housing (4) of the motor, and they are connected by a connecting hole (6) so that pressure changes in the housing (4) cause the elastic membrane (9) to vibrate. The connecting lever (12) connects the membrane (9), a small tubular bellows (14) and a large tubular bellows (13). By precompression in the housing (4), the membrane (9) moves so that the tubular bellows (13) and (14) move from the small (14) to the large bellows (13). This increases the working space (11) of the pump (8), creates is under pressure, so the fuel enters through the intake valve (10). As the pressure in the housing (4) drops, the membrane (9) and thus the bellows (13) and (14) move in the opposite direction, so the pressure increases. of fuel in the working space (11), the pressure valve (15) opens and the fuel, through the pipe (16), goes to the injection valve (21) which injects it into the cylinder (1) of the engine as soon as the fuel pressure overcomes the spring (20) and the needle (21).

The vibration frequency of the membrane (9) is identical to the number of revolutions of the crankshaft (5). The vibration amplitude of the membrane (9) is proportional to the difference in precompression and presuction pressures, so it varies depending on the amount of air admitted into the housing (4). The accelerator valve (3) regulates the amount of air and doses the required amount of fuel for the current engine operating mode.

The correction of the fuel dosage, with regard to the change in the operating temperature of the engine, is carried out by a bimetallic spring (17) acting on the valve (7) in the connecting hole (6) changing the amplitude of the vibrations of the membrane (9).

The fuel pressure in the working space (11) of the pump (8) is increased, in relation to the absolute pressure in the engine housing (4), by a coefficient that is the quotient between the surface of the membrane (9) and the difference between the surfaces of the tubular bellows (14) and (13). .

Claims (1)

1. Pneumatic system of direct fuel injection into two-stroke otto engines characterized by the fact that the fuel is injected directly into the cylinder (1) of the engine at the beginning of the compression stroke after the piston (2) closes all the openings of the cylinder (1), and the fuel supply is provided by a pneumatic differential pump (S) whose operation uses a cyclical change of pre-suction pressures and air precompression produced by the piston (2) in the engine housing (4), so vibrations of the elastic membrane (9) occur synchronized with the movement of the piston (2), and by means of the connecting lever (12) the vibrations are transmitted to the tubular bellows (13) and ( 14) which are of different diameters, so in accordance with the vibrations the working space (11) of the pump (8) increases and decreases so that the fuel is sucked in through the suction valve (10) and transported towards the injection valve (21) which injects it into the cylinder (1) engine. STATEMENT OF USE OF THE INVENTION The pneumatic system of direct fuel injection is primarily intended for two-stroke Otto engines, but it can also be applied to two-stroke Diesel engines. The system is suitable for installation on engines that are already in operation because it is simple and cheap, and the adaptation of the engine is minor. It completely replaces the carburetor, and the investment is returned in a very short time through a significant reduction in fuel consumption and much cleaner exhaust gases. Of course, the system is most efficient on new engines. The use of the invention is also possible wherever some cyclical change in gas pressure needs to be converted into movements or pulses synchronized with the rhythm of the pressure change.