Engine glow plug systems and methods
AssigneeCaterpillar Inc.
InventorsKenneth A. Baumgartner, Michael A. Caruthers, Christopher F. Gallmeyer, Robert L. Miller, Kenneth J. Suda
Life of this patent
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Abstract
An AC glow plug system is provided that includes a static converter for DC to AC conversion. Control techniques include varying the converter duty cycle according to glow plug temperature and other parameters such as engine air or coolant temperatures for smooth running as well as for prolonging glow plug life. Control is also varied according to fuel system characteristics and fuel composition.
Claims24
An engine glow plug system comprising:
- glow plugs in respective cylinders of a multicylinder diesel cycle engine where the glow plugs each include a ceramic material with an ion conduction characteristic;
- an alternating current (AC) power source arranged to apply AC power to the glow plugs, said power source comprising a converter, and a direct current (DC) source applying input DC power to the converter, where the converter is a static converter connected to convert the DC power to AC power applied to the glow plugs;
- and
- a controller connected with the converter to control a duty cycle of the converter.
An engine glow plug system comprising:
- glow plugs in respective cylinders of a multicylinder diesel cycle engine receiving a directly injected fuel;
- an alternating current (AC) power source arranged to apply AC power to the glow plugs, said power source comprising a converter, and a direct current (DC) source applying input DC power to the converter, where the converter is a static converter connected to convert the DC power to AC power applied to the glow plugs;
- and
- a controller connected with the converter to control a duty cycle of the converter.
An engine glow plug system comprising:
- glow plugs in respective cylinders of a multicylinder diesel cycle engine;
- an alternating current (AC) power source arranged to apply AC power to the glow plugs, said power source comprising a converter, and a direct current (DC) source applying input DC power to the converter, where the converter is a static converter connected to convert the DC power to AC power applied to the glow plugs;
- and
- a controller connected with the converter to control a duty cycle of the converter with the controller receiving signals representing voltage (V) applied to the glow plugs and current (I) in the glow plugs.
An engine glow plug system comprising:
- glow plugs in respective cylinders of a multicylinder diesel cycle engine;
- an alternating current (AC) power source arranged to apply AC power to the glow plugs, said power source comprising a converter, and a direct current (DC) source applying input DC power to the converter, where the converter is a static converter connected to convert the DC power to AC power applied to the glow plugs and includes a plurality of switching transistors connected in an H-bridge configuration;
- and
- a controller connected with the converter to control a duty cycle of the converter.
An engine glow plug system comprising:
- glow plugs in respective cylinders of a multicylinder diesel cycle engine;
- an alternating current (AC) power source arranged to apply AC power to the glow plugs, said power source comprising a converter, and a direct current (DC) source applying input DC power to the converter, where the converter is a static converter connected to convert the DC power to AC power applied to the glow plugs;
- and
- a controller connected with the converter to control a duty cycle of the converter with the converter arranged to receive one or more input signals representing one or more engine and glow plug conditions and to process the input signals to achieve a desired glow plug temperature according to a predetermined strategy with the glow plug temperature at a minimum level sufficient for efficient combustion to prolong glow plug life.
A method of operating a diesel engine glow plug system having glow plugs in respective cylinders and a power source for energizing the glow plugs independent of engine running, comprising the steps of:
- sensing parameters representing engine temperature and glow plug temperature;
- maintaining a controlled glow plug temperature substantially continuously during and after engine starting including responding to engine cooling resulting from lightly loaded running of the engine by applying controlled power to the glow plugs during light load conditions while ensuring a smooth transition to running at a higher load level.
The method of claim 20 further comprising:
- sensing information related to the composition of the fuel supplied.
A method of operating a diesel engine glow plug system having glow plugs in respective cylinders and a power source for the glow plugs independent of engine running, where the engine has a fuel system dependent on an engine oil pressure for direct injection of fuel into the cylinders, comprising the steps of:
- initiating an engine start phase including cold cranking of the engine and supply of power to the glow plugs;
- sensing glow plug temperature and engine oil pressure;
- determining predetermined conditions at which the engine oil pressure is suitable for fuel injection and the glow plug temperature is suitable for fuel combustion;
- and
- injecting fuel into the engine only during both the described conditions of engine oil pressure and glow plug temperature.
Dependencies are inferred from the claim text.