DD234931A1 - DEVICE FOR PYROMETRIC TEMPERATURE MEASUREMENT IN EXHAUST CHANNELS - Google Patents

Abstract

The solution according to the invention relates to the measurement of the exhaust gas temperatures of Otto and Zuendstrahlmotoren with low response time, but is also suitable for other internal combustion engines. With the device, the exhaust gas temperature can be determined at a fixed point using the sensitive pyrometer, which makes it interesting for the solution of certain research and monitoring tasks. The arrangement is characterized in that a small body is arranged as a transformer at the measuring point. Its surface layer is such that, in contrast to the core, it quickly adopts the exhaust gas temperature, which is converted into a measurement signal in a pyrometric way. The mechanically connected design of the transmitter and the sensor installed in the duct wall is expedient, as a result of which an exact positioning relative to one another is ensured.

Description

Field of application of the invention

The invention is applicable to internal combustion engines, also in channels, which are traversed by gases that do not contain solids or other depositing substances. The invention is particularly suitable for gasoline and Zündstrahlmotoren.

Characteristic of the known technical solutions

In general, the exhaust gas temperature is measured on internal combustion engines by means of jacketed thermocouples. Most such temperature sensors have a relatively high response time, which only allow the measurement of steady state values. For certain technical tasks, however, it is necessary to detect the temperature profile in the exhaust system or a sudden change in temperature very quickly. This is only possible with special encoders, but often have the disadvantage of low mechanical stability.

Object of the invention

The invention has the goal to be able to perform the measurement of the temperature profile in the exhaust system or sudden changes in temperature time delay. .

Explanation of the essence of the invention

The invention has the objects of finding a technical solution which realizes the object of the invention, which is free from the deficiencies of the known technical solutions.

The essence of the invention is that a small body with a large surface, low heat capacity and small mass is arranged as a transformer at a representative of the specifically required measured value in the exhaust gas quay, which has good properties in questions heat transfer. This transformer can be suitably designed as a spherically formed, a low thermal conductivity exhibiting body, on the surface of a thin layer of a material with low heat capacity and good heat transfer properties is applied.

He is surrounded by the exhaust gas. Its surface takes on the temperature of the gas. On its surface a pyrometric transducer is optically aligned, which constantly provides a characteristic of the temperature of this surface signal. In this way it is possible to detect the temperature of the exhaust gas at a defined location.

The arrangement is chosen so that the transducer with its measuring channel has only a small goniometric deviation in the flow direction to protect it from damage. The inputs of the measuring channel can be designed by suitable mechanical details in the exhaust duct so that they exert an additional protective effect against mechanical deposits in the measuring channel or on the transducer. In order to enable an exact positioning of the transformer, the holder of the same is possible on an extension of a locked in the measuring channel, also fixing the transducer sleeve.

embodiment

The solution according to the invention will be explained with reference to three figures. In Figure 1, the arrangement is shown in a straight exhaust duct 1, which is flowed through in the arrow direction. In the measuring channel 2, the complete arrangement has been inserted and locked in the drawn position. The inserted arrangement consists of the sleeve 3, which receives the complete pyrometric Meßwertaufnehmer4, and at the extension 5 of the spherical transformer is attached. To the measuring channel 2, an annular elevation 9 is arranged, which serves as protection against particles located in the near-wall flow.

From Figure 2, the attachment of the transformer 6 and its structure can be seen. The extension 5 is formed at its end so as to protrude into the core 7 of the transformer 6. The core 7 is formed of a ceramic material with a smooth but blunt surface spherical. It is surrounded by a metal layer 8 several microns thick.

FIG. 3 shows a further possible arrangement. The exhaust duct 1 has a strong curvature, wherein the flow direction is again indicated by the arrow. Notwithstanding the variant shown in Figure 1, the sleeve 3 was so lang.ausgeführt that it projects into the exhaust passage 1. Therefore, it is possible to dispense with another protective device.

Claims (3)

Invention claim: 1. A device for pyrometric temperature measurement in exhaust ducts of internal combustion engines, preferably Otto and Zündstrahlmotoren, characterized in that at a representative point in the exhaust duct (1) a small body with a large surface, low heat capacity and small mass as a transformer (6) is arranged that further arranged on the surface of a pyrometrically oriented, mechanically connected to the transmitter (6) and this holding transducer (4) in a sleeve (.3) within a measuring channel (2), and that this measuring channel (2) has a low goniometric Deviation from the flow direction of exhaust gas, wherein its confluence with the exhaust duct (1) may have these protect against damage details. 2. Device according to item 1, wherein the transformer (6) has a core (7) with low thermal conductivity, characterized in that it should have a metal layer (8) with good heat transfer properties. 3. Device according to item 1 and 2, characterized in that the transformer (6) may be spherical. For this 1 page drawings Field of application of the invention The invention is applicable to internal combustion engines, also in channels, which are traversed by gases that do not contain solids or other depositing substances. The invention is particularly suitable for gasoline and Zündstrahlmotoren. Characteristic of the known technical solutions. In general, the exhaust gas temperature is measured on internal combustion engines by means of jacketed thermocouples. Most such temperature sensors have a relatively high response time, which only allow the measurement of steady state values. For certain technical tasks, however, it is necessary to detect the temperature profile in the exhaust system or a sudden change in temperature very quickly. This is only possible with special encoders, but often have the disadvantage of low mechanical stability. Object of the invention The invention has the goal to be able to perform the measurement of the temperature profile in the exhaust system or sudden changes in temperature time delay. Explanation of the essence of the invention The invention has the objects to find a realizing the object of the invention technical solution that is free of the shortcomings of the known technical solutions. The essence of the invention is that a small body with a large surface, low heat capacity and small mass is arranged as a transformer at a representative representative of the specifically required measurement point in the exhaust duct, which has good properties in questions heat transfer. This transformer can be suitably designed as a spherically formed, a low thermal conductivity exhibiting body, on the surface of a thin layer of a material with low heat capacity and good heat transfer properties is applied. He is surrounded by the exhaust gas. Its surface takes on the temperature of the gas. On its surface a pyrometric transducer is optically aligned, which constantly provides a characteristic of the temperature of this surface signal. In this way it is possible to detect the temperature of the exhaust gas at a defined location. The arrangement is chosen so that the transducer with its measuring channel has only a small goniometric deviation in the flow direction to protect it from damage. The inputs of the measuring channel can be designed by suitable mechanical details in the exhaust duct so that they exert an additional protective effect against mechanical deposits in the measuring channel or on the transducer. In order to enable an exact positioning of the transformer, the holder of the same is possible on an extension of a locked in the measuring channel, also fixing the transducer sleeve. Ausführungsbeispiei The solution according to the invention will be explained with reference to three figures. In Figure 1, the arrangement is shown in a straight exhaust duct 1, which is flowed through in the arrow direction. In the measuring channel 2, the complete arrangement has been inserted and locked in the drawn position. The inserted arrangement consists of the sleeve 3, which receives the complete pyrometric transducer 4, and at the extension 5 of the spherical transformer 6 is attached. To the measuring channel 2, an annular elevation 9 is arranged, which serves as protection against particles located in the near-wall flow. From Figure 2, the attachment of the transformer 6 and its structure can be seen. The extension 5 is formed at its end so that it projects into the core 7 of the transformer 6. The core 7 is formed of a ceramic material with a smooth but blunt surface spherical. It is surrounded by a metal layer 8 several microns thick. FIG. 3 shows a further possible arrangement. The exhaust duct 1 has a strong curvature, wherein the flow direction is again indicated by the arrow. Notwithstanding the variant shown in Figure 1, the sleeve 3 was designed so long that it protrudes into the exhaust passage 1. Therefore, it is possible to dispense with another protective device.