Measurement of Light Vehicle Stationary Exhaust System Sound Level Engine Speed Sweep Method

In this study, a double mode muffler that can automatically adjust the exhaust resistance according to the engine speed was designed. Based on computational fluid dynamics theory, the governing equation and turbulent equations for numerical simulation of muffler were established. The pressure loss and the internal flow characteristics of the double mode muffler were analyzed by CFD software. The influence of the distance between the main and submuffler on the flow field of exhaust system was researched. In addition, the internal pressure distribution, the turbulence intensity distribution and the velocity vector diagram of the dual mode muffler were also obtained. The pressure loss of double mode muffler is mainly distributed in the area of air mutations. Main silencer plays a leading role in the entire exhaust system. Therefore, the trend of the pressure loss of the exhaust system with the change in the distance between main and auxiliary muffler was also obtained. When the distance between the main and auxiliary silencer changed from 50 mm to 300 mm, the pressure loss of exhaust system muffler first increased and then decreased, and following this, continued to increase. The results will provide a theoretical basis for designing complex exhaust system.

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Investigations of the temperature distribution in the exhaust system of an aircraft piston engine

Combustion Engines ◽

10.19206/ce-2019-203 ◽

2019 ◽

Vol 177 (2) ◽

pp. 12-18

Author(s):

Jacek CZARNIGOWSKI ◽

Krzysztof SKIBA ◽

Kamil DUBIEŃSKI

Keyword(s):

Temperature Distribution ◽

Engine Speed ◽

Exhaust System ◽

Heat Emission ◽

Piston Engine ◽

Engine Operation ◽

Bench Tests ◽

Exhaust Gases ◽

Engine Cooling ◽

Wide Range

Ultralight aviation is based on piston engines requiring both performance and reliability. An important aspect is also the require-ments for the installation of such an engine on an airframe, especially its heat emission. This is firstly because of the need to ensure proper engine cooling and secondly because composite elements of the airframe skin are not exposed to excessive overheating. For this purpose, bench tests of the temperature distribution of the exhaust system of ROTAX 912 engine were carried out. Measurements were taken at 6 points of the exhaust system, where the temperature of the exhaust gases and exhaust pipes were measured. The tests covered a wide range of engine operation. The paper presents the temperature distribution at selected points in relation to the engine speed and load.

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Measurement of Light Vehicle Exhaust Sound Level Under Stationary Conditions

10.4271/j1169_198509 ◽

1985 ◽

Author(s):

Keyword(s):

Sound Level ◽

Vehicle Exhaust ◽

Stationary Conditions ◽

Light Vehicle

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NEMO project: acoustic detection of vehicle engine speed

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-1718 ◽

2021 ◽

Vol 263 (5) ◽

pp. 970-980

Author(s):

Truls Berge ◽

Viggo Henriksen

Keyword(s):

Engine Speed ◽

Exhaust System ◽

Aggressive Driving ◽

Noise Levels ◽

High Noise ◽

Vehicle Engine ◽

High Acceleration ◽

High Engine Speed ◽

Urban Conditions ◽

The Impact

As part of the EU Horizon2020 project NEMO, SINTEF has developed an algorithm to detect the engine speed of passing vehicles. Some road vehicles can emit abnormal high noise levels or high levels of exhaust gases in urban conditions. The high noise level can be related to aggressive driving (high acceleration and high engine speed), to a modified or malfunctioning exhaust system, or to other vehicle defects. It is well-known that many motorcycles or mopeds often are equipped with non-original exhaust mufflers, giving high noise levels that can be a nuisance to the community. In the NEMO project, the detecting of so-called high emitters (HE) is essential to reduce the impact of such vehicles on the environment and public health. To enable to categorize HE vehicle based on the driving behaviour, it is necessary to detect both acceleration and corresponding engine speed. The paper describes the principle of the algorithm developed and results from testing on vehicles, including a motorcycle. This test shows that it is feasible to estimate the engine speed, also when the vehicle is accelerating, if the number of cylinders is available for the estimation. Further testing of the algorithm is planned within the NEMO project.

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