Measuring and testing – Volume or rate of flow – Thermal type
Reexamination Certificate
2008-07-22
2008-07-22
Patel, Harshad (Department: 2855)
Measuring and testing
Volume or rate of flow
Thermal type
Reexamination Certificate
active
11206772
ABSTRACT:
The time it takes for a hot-wire airflow meter to begin to operate normally upon startup of an automobile is reduced. A heat-generating resistor Rh for measuring airflow rate, a temperature-compensating resistor Rc, and a resistor R1for detecting the current through the heat-generating resistor are connected in parallel. A differential voltage between a power supply voltage Vb and the voltage across the emitter-collector junction of transistors Q1, Q2, or Q3is applied to each of the heat-generating resistor Rh, temperature-compensating resistor Rc, and current-detecting resistor R1. The transistors Q1, Q2, and Q3form a current mirror circuit20, by which the ratio of currents through the heat-generating resistor Rh, temperature-compensating resistor Rc, and current-detecting resistor R1is determined. The current ratio is maintained to be a predetermined ratio even if the heating current is controlled by an operational amplifier21due to an increase or decrease in airflow rate.
REFERENCES:
patent: 3490272 (1970-01-01), Russell
patent: 5137370 (1992-08-01), McCulloch et al.
patent: 5616843 (1997-04-01), Schifferl et al.
patent: 5685194 (1997-11-01), McCulloch et al.
patent: 5824895 (1998-10-01), Itsuji et al.
patent: 6032525 (2000-03-01), Suetake
patent: 6032526 (2000-03-01), Akamatsu
patent: 6349596 (2002-02-01), Nakada et al.
patent: 6450024 (2002-09-01), McCulloch et al.
patent: 8-304136 (1996-11-01), None
patent: 2002-116074 (2002-04-01), None
Hitachi , Ltd.
Mattingly ,Stanger ,Malur & Brundidge, P.C.
Patel Harshad
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