DE4000911A1 - IC engine valve control system - involves hydraulic circuit incorporating spring-loaded plane-surface check valve - Google Patents

Abstract

The hydraulic valve control is used in an IC engine. The engine incorporates a control housing (8) which has a continuous bore and a parallel stepped bore. A spring-loaded plane surface check valve (14) is arranged in the stepped section and the section of the bore above it opens into a channel (8c) leading to a closure piece (10) connected to a controlled pipe (15), with a cross-bore connection (8b) to the annular space (8a). USE/ADVANTAGE - Easily assembled valve control which requires only one pipe connection per valve unit.

Description

The invention relates to a by a pressure generator or pump and over hydraulic valve operated valve timing for engines.

Such a valve control has already been proposed, which by the performance of the pump is much better than that of previously known hydraulic valve controls because the valve is delayed its kinetic energy is sent back to the pressure oil side. In addition to the Minimizing the energy expenditure was the advantage of the invention in one significant reduction in construction costs, in the elimination of the valve spring as well as saving space.

The disadvantages of this valve control were the required 3 Pipe connections per valve control unit and in the unsafe function of the Valve ring which measures the active return stroke of the valve. Furthermore, the the assembly of the valve control unit was not solved structurally.

The invention has for its object with only one pipe connection per Valve control unit get along, an easy assembly of the valve with its Guidance despite an inseparable connection between valve stem and piston ensure and proper functioning and metering of the active To ensure valve return stroke.

This object is achieved in that the control housing Valve control unit for accommodating the valve guide, the valve stem with its piston and its cylinder and an upper closure with Pressure oil supply a through hole and parallel to this hole has stepped bore in which there is a connecting piece at the bottom a hollow drilled valve body and a perforated plate and above in a spring-loaded flat surface back in a stepped bore section check valve and that the overlying bore in a Closing piece leading channel that leads to a controlled pipeline is connected and that the bore containing the check valve cut through a cross hole with the annular space between the cylinder and outgoing housing bore is connected and that the cylinder at the lower end has radial bores.

It is a further advantageous feature that the mentioned connection piece has a wide overflow groove in the upper part of its bore and the in the bore sliding valve body a downward longitudinal bore and  has cross holes connected to the latter in the upper part and that the stroke the valve body in the bore of the connecting piece upwards through a Perforated plate is limited and that the connection piece below in one turn sealed by a round ring and with a pressure oil channel in the cylinder head connected is.

Another feature is that the valve guide at the top Has groove in which a split retaining ring is inserted that the piston e.g. B. permanently connected to the valve stem by a flanged neck is that the cylinder in which the piston slides and in a known manner forms an upper and a lower work area, up against the closure piece and is supported at the bottom against an intermediate bush, the intermediate in turn, the bushing attaches to the retaining ring at the bottom and to a retaining bracket which also presses the valve housing onto the cylinder head.

The invention has the following advantages over the proposed:

• - The number of pipe connections is reduced from 3 to 1.
• - The valve - piston - valve guide assembly can be inserted from below into the corresponding Bore are inserted, making the assembly much easier is.
• - The overall height of the valve control is further reduced.
• - The metering of the active return stroke is improved.

All the advantages of the proposed invention such as reducing the moving Mass to 1/3 compared to previous ohc controls are retained.

An embodiment is shown in the drawing. A connected Hydraulic diagram illustrates the mode of operation.

The embodiment is worked through constructively to which in the To make practical advantages visible.

A valve guide 2 is pushed onto a valve stem 1 and a piston 3 is non-detachably connected to the valve stem 3 , for example by rolling a neck-shaped attachment into a corresponding groove. The valve guide 2 is inserted from below into a corresponding bore of the cylinder head 4 and secured by a split retaining ring 5 inserted into a groove. An intermediate bushing 6 is pushed onto the upper part of the valve guide and encloses a seal 7 and at the same time serves as a centering for the through bore of the control housing 8 . In this through hole, a cylinder 9 is inserted and centered by an upper and lower collar. The piston 3 slides in the inside diameter of the cylinder and forms an upper 9 a and a lower working space ( 9 b). The lower working chamber 9 b is connected to an annular chamber 8 a by radial bores and to the stepped bore section via a transverse bore 8 b. Above the cylinder 9 there is a closure piece 10 which, like the entire control housing 8, is held by a clamping bracket 16 . In a stepped bore arranged parallel to the continuous bore, there is a connecting piece 11 in the lower section which accommodates a hollow-bore valve body 12 . The connection stub 11 is sealed by a round ring against rotation in the cylinder head 4 . There is a perforated plate 13 above the connection piece, which limits the stroke of the hollow-drilled valve body. In the stepped bore section there is a check valve 14 , designed as a flat surface valve, which does not flow any pressure oil from the stepped bore section or, in the case of an enlarging lower working chamber 9 b, allows drain oil from the controlled line 15 to flow through this channel 8 b. Finally, the closure piece 10 has a longitudinal bore, radial bores and an annular groove, which enable the connection to the controlled line 15 via the channel 8 c.

The control housing for intake and exhaust match and are arranged side by side and attached to the cylinder head by a bracket 16 and screws.

The supply of the valve control with pressure oil can be seen from the hydraulic diagram attached to the side. As in the case of the invention already proposed, the pump P supplies the inlet and outlet valves with pressure oil, with the outlet or shuts off the line, via corresponding control devices E and A. The drain oil is sucked in via the check valves 17 .

Because the control units do not constantly drain pressure oil, there is pressure memory for the temporary absorption of pressure oil and for the compensation of Pressure surges necessary.

A line to a respective injection pump unit 20 with injection valves is connected to the respective controlled lines to the inlet valves. The injection pump unit 20 consists of a small cylinder with a small differential piston 21 , on the end face of which the controlled pressure acts and on the annular surface of which there is constant pump pressure. Acts in the controlled line 15 pressure, the small differential piston 21 moves to the right, the nozzle needle 22 lifts off and fuel VK is injected. The amount of fuel injected is therefore dependent on the opening pressure and duration at the inlet valve. The hydraulic drive of a gasoline injection lends itself and with the arrangement outlined here, it is structurally simple to establish a functional relationship between the time cross section of the inlet valve and the injection quantity.

For the mode of operation of this valve control, the invention already proposed can be used. The design of the hollow-drilled valve 12 , which measures the active return stroke when the valve or valve stem 1 is returned, has changed. Since it is flown from below during the return stroke, it moves upwards without the action of a spring force until it strikes the perforated plate 13 . This stroke is equal to the active return stroke of the valve if the outer diameter of the hollow-drilled valve body and valve stem are the same.

Since the valve continues to move as a result of inertia, drain oil is drawn in from the control line 15 via the check valve 14 . This is possible because the controlled line 15 is connected to the drain anyway during the return stroke. This means that the separate drain line used in the invention already proposed can be omitted.

List of reference numbers

1 valve stem
2 valve guide
3 pistons
4 cylinder head
5 retaining ring
6 intermediate socket
7 seal
8 control housings
8 a annulus
8 b cross hole
8 c channel
9 cylinders
9 a upper work area
9 b lower work area
10 closure piece
11 connecting pieces
12 hollow valve body
13 perforated plate
14 check valve
15 controlled line
16 clamps
17 check valve
20 injection pump unit
21 small differential pistons
22 nozzle needle

Claims (4)

1. Hydraulic valve control for internal combustion engines, which is actuated by a pump via control units, and form differential pistons in the valve stems together with pistons, characterized in that the control housing ( 8 ) of the valve control unit for receiving the valve guide ( 2 ), the valve stem ( 1 ) with a piston ( 3 ) and its cylinder ( 9 ), as well as a closure ( 10 ) with pressurized oil supply has a continuous bore and parallel to it a stepped bore in which a connection ( 11 ) with a hollow-drilled valve body ( 12 ) and a perforated plate ( 13 ) and further up in a stepped bore section there is a spring-loaded flat face check valve ( 14 ) and that the overlying bore opens into a channel ( 8 c) leading to the closure ( 10 ), which leads to a controlled line ( 15 ) is connected and that the, the check valve ( 14 ) containing bore section by e ine transverse bore ( 8 b) is connected to the annular space ( 8 a) and that the cylinder has radial bores at its lower end. 2. Valve control according to claim 1, characterized in that the connecting piece ( 11 ) has a wide overflow groove in the upper part of its bore and the valve body sliding in the bore ( 12 ) has a downward-pointing longitudinal bore and radial bores connected to the latter in the upper part has and that the stroke of the valve body ( 12 ) in the bore of the connecting piece ( 11 ) is limited by a perforated plate ( 13 ) and that the connecting piece ( 11 ) is connected below with a pressure oil channel in the cylinder head ( 4 ). 3. Valve control according to claim 1 and 2, characterized in that the valve guide ( 2 ) at the upper end has a groove into which a part ter retaining ring is inserted, that the piston ( 3 ), for example by a flange th throat with the Valve stem ( 1 ) is connected so that the cylinder ( 9 ) in which the piston ( 3 ) slides and forms in a known manner an upper ( 9 a) and a lower working space ( 9 b), above against the closure ( 10 ) and bears downwardly against an intermediate sleeve (6), wherein the (6) applies between the bush at the bottom of the retaining ring (5) and the closure (10) up to a clamping bracket (16) at the same time the control housing (8) to the cylinder head ( 4 ) presses. 4. Valve control according to claim 1 to 3, characterized in that to the respective, leading to the intake valves, controlled lines 15 A spray pump units ( 20 ) are connected, in the small cylinders of which small differential pistons ( 21 ) are arranged with a nozzle needle 22 , The end face of the small differential piston ( 21 ) with controlled pressure oil and the annular surface are constantly pressurized with pressure oil and the space around the nozzle needle is connected to a fuel line (VK) via a check valve.