CS198708B1 - Check valve for fuel injection pumps of high-speed oil engines - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a non-return valve for injection pumps of high-speed diesel engines, providing a permanent connection between the injection pump working space and the discharge line through a connection channel having a smaller flow cross-section than the discharge cross-section.

Injection pumps operating without discharge valves are known in which the pressure flow is controlled by a throttled flow cross section, for example, in a transfer passage in the cylinder during the fuel transfer period. In addition to a number of known advantages, these injection pumps have the disadvantage that they require a relatively high boost pressure of fuel that ensures perfect filling of cavitation cavities in the discharge line during the piston suction stroke during the filling period.

One known solution to this problem is a lip inserted between the injection pump working space and the start of the discharge line, which releases the required cross-section when the fuel is discharged, but covers this flow cross-section during the relief process. until the pressure in the discharge line drops to the pressure in the pump filling chamber. However, this solution is production-intensive.

As the tests have shown, the same effect, ie the operation of the injection pump without requiring high feed pressure, can be achieved by using a simple non-return valve, while securing the pressure.

IBS 70 «connection of the pump β working space through the discharge pipe through a narrow channel whose diameter is smaller than the diameter of the discharge pipe. This channel can be formed directly in the non-return valve or 1 outside it.

SUMMARY OF THE INVENTION The non-return valve is ball-shaped, spring-loaded into a conical seat in a backing extending into a wide central channel, in which the thrust is pressed against the face of the valve by a throat.

In the drawing, a check valve according to the invention is shown in vertical section by sohematiques.

The check valve has the shape of a ball 2 of steel or other suitable material abutting a conical seat in the backing 92 tightened by the neck ± to the roll g, the conical seat opening into a wide channel 11 in the backing gg. A channel gfi, connecting the space below and above the ball-shaped valve g, is drilled in the washer 92. off the axis of the channel 93. The ball g is pressed into the seat in the washer 92 by a biased spring 91.

When the fuel is displaced by piston J, the non-return valve-ball g is raised and releases a large cross-sectional area in its seat to prevent excessive flow losses in the valve.

In the period of fuel overflow when the control edge exposes the full channel gg in the cylinder g, the fuel pressure drops in the space above the piston g. By overpressure of the fuel in the known and therefore not shown discharge pipe and the biased spring g1, the ball check valve 2 engages ^{in the} seat, the expansion of the fuel from the discharge pipe towards the filling of the injection pump chamber ϋ. below and above the valve.

The advantage of the described check valve is its simplicity and low production costs, making it suitable for large-scale production.

Claims (1)

SUBJECT OF THE INVENTION Non-return valve for high-speed diesel engine injection pump providing a permanent connection between the injection pump working space and the discharge line through a channel with a smaller flow cross-section than the discharge line cross-section, characterized in that it is ball shaped (9) a conical seat in the backing (92) extending into a wide central channel (93), in which the backing (92), pressed by the neck (4) to the face of the valleys (2), is located outside the axis of the central channel (93) .