Abstract: A mass airflow measuring device includes an air passageway defined in a duct. A first channel communicates with the air passageway via at least one first aperture to allow air flowing through the air passageway to enter the first channel. A second channel is located downstream from the first channel. A sample channel communicates the first channel with the second channel. A mass airflow sensor is located in the sample channel and is adapted to receive air flowing in the sample channel. The sample channel is defined in a housing which has a chamber adapted to accommodate one of a variety of differently configured mass airflow sensors. The sensor is adapted to output an airflow signal based on air flowing past the sensor. A processing unit communicates with the sensor and is adapted to receive the airflow signal from the sensor.

Abstract: An engine muffler and spark arrester includes an oval shaped outer tube extending along an axis and having an inlet end and an outlet end. A plurality of substantially identical nested oval shaped disks are disposed coaxially adjacent the outlet end. Each of the disks has an oval shaped centrally located aperture. An inner tube is disposed coaxially within the outer tube. The inner tube has a circular inlet end and an oval-shaped outlet end. An oval end cap is disposed adjacent the disks. A sound absorbent material can be disposed in a cavity defined between the inner tube and the outer tube. An oval-shaped inlet cap is secured to the inlet end of the outer tube with the inlet cap having a circular centrally located aperture extending therethrough. An oval-shaped outlet cap is secured to the outlet end of the outer tube. The outlet cap has an oval-shaped centrally located aperture extending therethrough.