Apparatus and method for detecting intake air mass flow rate
An intake air mass flow rate detection apparatus is described using a Karman vortex air flow sensor, comprising a Karman vortex air flow sensor arranged in an intake passage of an internal combustion engine, comparison means for obtaining a digital signal by comparison of an analog signal obtained from the output of the Karman vortex air flow sensor with a predetermined threshold level, and volume flow rate calculation means using a value proportional to the frequency of the digital signal as the intake air volume flow rate. The apparatus also consists of: amplitude hold means for holding the amplitude value of analog signals obtained from the output of the Karman vortex air flow sensor; storage means for storing in advance a relationship between the intake air volume flow rates and the amplitude values of the analog signals obtainable from the output of the Karman vortex air flow sensor under standard atmospheric pressure; mass calculation means for multiplying the intake air volume flow rate obtained by the volume flow rate calculation means by the intake air density for obtaining the intake air mass flow rate.
- Assignee:
- Toyota Jidosha Kabushiki Kaisha, Toyota
- Patent Number(s):
- US 4589279
- OSTI ID:
- 5703176
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
330100* -- Internal Combustion Engines
AIR FLOW
AMPLITUDES
ANALOG SYSTEMS
ATMOSPHERIC PRESSURE
CALCULATION METHODS
COMPUTERIZED CONTROL SYSTEMS
CONTROL SYSTEMS
DENSITY
DIGITAL SYSTEMS
ENGINES
FLOW RATE
FLOWMETERS
FLUID FLOW
FREQUENCY DEPENDENCE
GAS FLOW
HEAT ENGINES
INTAKE STRUCTURES
INTERNAL COMBUSTION ENGINES
MEASURING INSTRUMENTS
MECHANICAL STRUCTURES
MEMORY DEVICES
METERS
PHYSICAL PROPERTIES
SIGNALS
VORTEX FLOW