Speed sensing
AssigneeSmiths Industries Limited
InventorDominick Paul Edmund Barnard
Life of this patent
Estimating the term…
Abstract
Diesel engine speed is sensed by a thermistor which is disposed within an air inlet of the engine manifold so that the resistance of the thermistor varies in accordance with the temperature of the air within the inlet and thus in accordance with the speed of the engine. The thermistor is connected in a transistor circuit which derives, in response to the change in resistance of the thermistor, an electric signal having a frequency which varies in accordance with engine speed.
Claims7
Speed sensing apparatus for a diesel engine in which air is intermittently drawn into a combustion chamber through a hot inlet of the engine, the air being warmed by the hot inlet comprising,
- a temperature-responsive device which has an electrical characteristic that varies in accordance with the temperature of the air in said hot inlet
- means supporting said device in said inlet of the diesel engne,
- said device being of the kind which has a response time to temperature variations permitting its said electrical characteristic to vary in accordance with the cyclical variations in the temperature of the air in said hot inlet occurring upon each revolution of the engine,
- and means responsive to said variation of said electrical characteristic of said device for deriving a signal indicative of engine speed.
A method of sensing speed of a diesel engine in which air is intermittently drawn into a combustion chamber through a hot inlet of the diesel engine, the air being heated by said hot inlet, which involves the steps of:
- disposing within said inlet of the diesel engine a device having an electrical characteristic that varies in accordance with cyclical temperature fluctuations of air within the said inlet as air is intermittently drawn therein and heated by said hot inlet and thus in accordance with the speed of the diesel engine,
- and sensing the frequency of said variation of the electrical characteristic to provide an indication of the speed of the engine.
A method of sensing diesel engine speed in which air is intermittently drawn into a combustion chamber through a hot inlet of the engine and is heated by said inlet comprising the steps of:
- generating a signal responsive to the cyclical fluctuations in the temperature of the air within an inlet of the diesel engine as air is intermittently drawn therein,
- and responding to the frequency characteristic of the generated signal to provide a measure of engine speed.
Dependencies are inferred from the claim text.