# US 4,398,868 A · Control apparatus for a gas dynamic pressure-wave machine for charging combustion engines

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- Number: US 4,398,868 A
- Document ID: US4398868A
- Status: Granted
- Kind: A
- Application number: 06/254,873
- Filed: 1981-04-16
- Granted: 1983-08-16
- Earliest claimed: 1980-05-02
- Assignees: BBC Brown, Boveri & Company, Limited
- Inventors: Christian Komauer; Andreas Mayer
- Web page: https://patentgrep.com/patent/US4398868A

## CPC

- F04F 13/00: Pressure exchangers
- F02B 33/42: with driven apparatus for immediate conversion of combustion gas pressure into pressure of fresh charge, e.g. with cell-type pressure exchangers
- G05D 7/0173: {using pivoting sensing element acting as a valve mounted within the flow-path}
- F04F: PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED {(evacuating by sorption F04B)}; SIPHONS {(conveying materials in bulk by flows of gas, liquid of foam B65G53/00)}
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES

## Abstract

A control apparatus for a gas dynamic pressure-wave machine for charging combustion engines. The inflow cross-sectional area of the gas pocket in the high-pressure exhaust channel is controlled in accordance with the desired operating conditions of the engine by a bimetallic flap or valve member as a function of the temperature of the high-pressure exhaust gas.

## Claims

### Claim 1

A control apparatus for use in a gas dynamic pressure-wave machine for charging combusion engines, comprising:
a pressure-wave machine provided with a high-pressure exhast gas channel;
said pressure-wave machine including a housing containing a cell rotor;
said high-pressure exhaust gas channel being provided with a gas pocket at a location before opening into the cell rotor in order to branch-off high-pressure exhaust gases into an auxiliary flow at predetermined operating conditions of the engine;
a flap member arranged in the high-pressure exhaust gas channel;
said flap member being fixedly clamped in the housing of the pressure-wave machine along one of its edges;
said flap member experiencing a bending deformation when exposed to temperature changes;
said flap member forming a partition wall between the high-pressure exhaust gas channel and the gas pocket; and
the flap member being structured to possess a temperature-dependent bending deformation whose magnitude and course corresponds to a temperature-dependent opening characteristic of an inflow cross-section of the gas pocket and which is desired for the pressure-wave machine.

### Claim 2 (depends on 1)

The control apparatus as defined in claim 1, wherein:
the flap member comprises a bimetallic element.

### Claim 3 (depends on 2)

The control apparatus as defined in claim 2, wherein:
said bimetallic flap member is composed of a combination of different metal pairings.

### Claim 4 (depends on 3)

The control apparatus as defined in claim 3, wherein:
said bimetallic flap member comprises two mutually contacting bimetallic pairings, the bending deformation of which is opposite to one another;
one of the bimetallic pairings experiencing an appreciably greater bending deformation throughout a lower temperature range than the other bimetallic pairing whose bending deformation is appreciably greater than the first bimetallic pairing in a higher temperature range.

### Claim 5 (depends on 2)

The control apparatus as defined in claim 2, wherein:
the bimetallic element is formed of two components;
the coefficient of thermal expansion of the one component of the bimetallic flap member markedly increasing in a lower temperature range and at most slightly increasing at an upper temperature range; and
the other component of the bimetallic element behaving conversely with respect to its coefficient of thermal expansion in the aforementioned temperature ranges.

### Claim 6 (depends on 5)

The control apparatus as defined in claim 5, wherein:
the coefficient of thermal expansion of the one component essentially does not increase in said upper temperature range.

### Claim 7 (depends on 2)

The control apparatus as defined in claim 2, further including:
flow divider means arranged in the high-pressure exhaust gas channel at the region of a fully open position of the bimetallic flap member; and
a gas pocket channel for feeding the gas pocket when the gas inflow to the gas pocket is blocked by the bimetallic flap member.