DE19711172A1 - Rotary piston engine - Google Patents

Abstract

The engine has a casing (12) with an inlet (18) and an outlet (20) for a driving substance, e.g. LH2, or O2. A pair of rotary pistons (14,16) are arranged between the inlet and the outlet. The pistons are arranged so that their rotational axes (26) are parallel and so that opposite linear regions of their circumferential surfaces have the same spacing when both pistons are rotated. Both the rotary pistons are between the inlet and the outlet of the casing. The pistons may be coupled to rotate in opposite directions at the same speed by gear wheels, either directly or through the action of toothed belts.

Description

1. The rotary piston engine has idle in the lower Pressure range (p1 <1.5 bar) the problem of charge loss, because in principle it only has a gap resistance s <0.1 [mm] is separated from the atmosphere.

In hydraulic engineering, a hydraulic diameter d _{h is} described, which has the following form:

where A represents the cross-sectional area and U the circumference this area is.

If the diameter of the inlet opening is of the order of magnitude of this hydraulic diameter d _h , no drive pressure can initially build up in the charge chamber (combustion chamber).

If the engine is loaded while idling (e.g. alternator is driven by residual pressure) or compressed air, the high output collapses during the combustion of H ² . An equivalent pressure to start the engine can only build up when it is ignited. Then, however, the charge losses are in the per mille range and are negligibly small.

2. Another unfavorable effect is the high energy density of H ² during combustion, which is not used effectively enough. The engine releases the thermal energy it receives to the exhaust, its walls and rotary pistons unused, where it could do work. It is easy to see that the engine gets hot very quickly. The thermal energy must therefore be conserved and better used for performance.

To 1
According to the mechanical engineering principle "Three parts running against each other cannot be sealed to each other", it is not possible to get all three parts completely hermetically sealed to each other at every moment. However, this is not necessary for the start-up phase until the ignition. With the sealing principle proposed here, a charge loss of approx. 20% results for the moment of a rotation of less than α «60 °. However, the engine starts to turn immediately, even with combustion chamber pressures p2 below <1.5 bar.

In Fig. 1 it is shown how the sealing problem can be solved.

It should be noted that no sealing is necessary on the running surfaces parallel to the flat sides of the rotary lobes. This results from the length of the sealing gap and the known relation Δp α i / d _h .

Grooves are milled into the convex ends of the rotary lobes so that the inserted sealing strips ( 5 ) with anchors cannot be thrown out by their centrifugal force during the rotation of the rotary lobes at the moment when they are not pressed against the motor wall or against the concave part of the adjacent piston will.

Since the pistons do not have Cassini curve shapes, but for fluidic reasons, their outlines are polylines with radii in the quadrants, these radii can be moved a bit along with the sealing strips. The piston ( 3 ) separates a gap of approx. <0.2 [mm]. This is also the movement of the sealing strips.

A sliding ramp ( 4 ) is provided for the sealing strips so that the sealing strips can slide along the wall again without impact. This sliding ramp causes an edgeless transition of the sealing strips from the concave part of the neighboring rotary piston to the contact with the wall again. This sliding ramp ( 4 ) is provided with the same radius of the outer dimension of the rotary lobes, but is inclined by approx. 5∘ against the tangent at the point of contact with the wall.

Another favorable circumstance improves the sealing problem significantly, as shown below.

To 2
The conservation of energy from hydrogen combustion and better use of it could be achieved as follows:

At the moment of the suction phase, water ( 1 ) is sprayed into the combustion chamber ( 2 ) via a spray nozzle ( 6 ). When igniting by the glow plug (or other ignition mechanisms) it is now achieved that the high energy density is distributed in superheated steam, the pressure increases significantly and more work can be done. There will be a higher pressure than has been the case up to now. The leak through the spray opening is negligible.

The sealing effect due to the water depositing on the piston is obvious. Since the Δp is directly proportional to the viscosity η, a higher gap resistance results from the fact that the η must be used for the liquid water and no longer that for the H ² or the air. The result varies by powers of 10 compared to that of the gas phase.

Even more so is the medium density ϕ for the Δp must be used, a much higher one is calculated Δp for the liquid phase as just for the gas phase.

Fig. 1 shows a cross section through the rotary piston engine with the arrangement of the sealing strips and the spray nozzle for water.

Claims (5)

1. Rotary piston ( 3 ) with a seal ( 5 ), which is protected from sliding out by centrifugal force from the groove by a hammer head shape. 2. Rotary piston ( 3 ) with a seal ( 5 ), which is passed back to the wall contact without impact on a sliding ramp ( 4 ). 3. Rotary pistons for a rotary piston engine according to the Claims 1-2 of only during a phase of α «60 ° allows a loss of charge. 4. spray nozzle ( 6 ) for water in a rotary piston engine such that the combustion energy of H ² / O ² in the combustion chamber ( 2 ) is preserved in superheated steam ( 1 ). 5. Due to the combustion energy conserved in water vapor ( 1 ), the combustion chamber pressure p ² increases considerably and the efficiency of the rotary piston engine can be increased considerably, in particular according to claims 1-4.