Wyniki wyszukiwania - BazTech

1

Fiber optic-based in-cylinder pressure sensor for advanced engine control and monitoring

Wlodarczyk M. T.

Silniki Spalinowe

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2012

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R. 51, nr 4

3-8

EN

This paper describes the design and performance of a miniature cylinder pressure sensor packaged either as a stand-alone device or integrated with a cylinder head gasket, glow plug, fuel injector, or spark plug. Benefitting from a fiber-optic based design the sensing element can operate at ultra-high temperatures and is not affected by EMI. This low cost device utilizes the principle of light intensity changes transmitted by two optical fibers upon reflection from a metal diaphragm deflecting under the effect of pressure. When the diaphragm thickness and shape are optimized, the sensor can operate up to 5 billion pressure cycles. The device is compensated for all temperature effects encountered in combustion engines, resulting from the thermal shock, engine load changes, and under-hood temperature fluctuations. Due to the diaphragm small thermal mass the sensor is subject to the thermal shock error if no heat shield is employed. While a suitable shield can almost eliminate the thermal shock error, it can get clogged in engines fuelled by diesel or landfill gas. For such engines a dual diaphragm construction offers a robust solution against soot and other combustion deposits as well as minimum thermal shock error. In comparison to a water cooled piezoelectric quartz transducer the present sensor offers the accuracy of ± 1.5% of reading at pressures above 5 bars, ± 0.1 bar error at pressure below 5 bars during compression, and the thermal shock error ranging from 0.1 bar to 0.3 bar dependent if a single or dual diaphragm is used. Such accuracy is possible with both stand-alone sensors as well as those 1.7 mm in diameter used in the "pressure sensing" cylinder head gaskets, glow plugs, fuel injectors, or spark plugs. This accuracy is maintained under all combustion conditions, sensor tip continuous temperatures up to 380 °C, signal conditioner temperature range of -40 °C to 140 °C, pressures up to 350 bar, and over frequency range of 0.1 Hz to 30 kHz. Such remarkable accuracy allows advanced engine controls based on highly accurate values of the Indicated Mean Effective Pressure, Mass Fraction Burned, Maximum Pressure Gradient, and Peak Pressure. Benefitting from sensor's high accuracy at both low and high pressures the device enables closed-loop control of fuel injection as well as in-cylinder prediction of mass air flow and engine NOx emission levels.

2

Glow plug integrated cylinder pressure sensor for closed loop engine control

Wlodarczyk M. T.

Journal of KONES

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2005

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Vol. 12, No. 3-4

369-374

EN

The PressureSense Glow PlugTM combines a miniature fiber optic-based cylinder pressure sensor with the automotive glow plug. The 1.7 mm diameter sensor is sealed inside a glow plug heater and the sensor signal conditioner is encapsulated into a “smart connector”. The sensor operates on the proven principle of light intensity changes, transmitted by two optical fibers, upon reflection from a deflecting metal diaphragm. The sensor materials, dimensions, and the assembly technique are optimized to compensate for diaphragm deflection dependence on temperature associated with engine load changes. The device is compensated for all major environmental factors encountered under the hood of an automobile including LED and photodiode temperature dependence and aging, fiber-to-opto-electronics coupling fluctuations, and vibration and humidity effects. Under combustion conditions the sensor offers the total accuracy of +/-1.5% over the projected sensor life of 10 thousand hours. Such high sensor accuracy allows advanced closed loop control strategies for diesel and HCCI engines based on real time computations of Indicated Mean Effective Pressure (IMEP) and mass fraction burned. These control strategies have been shown to result in as much as 12% reduction in NOx emissions and 15% of particulate emissions in a closed loop controlled diesel engine versus its conventional counterpart.

3

Long-life fiber-optic pressure sensors for monitoring and control of combustion engines

Poorman T., Arnold J., Coleman T., Wlodarczyk M. T.

Journal of KONES

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1999

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Vol. 6, No. 1-2

141-149

EN

This paper describes the design and performance of Optrand long-life high-temperature fiber-optic pressure sensors that have been specifically developed for monitoring and control of internal combustion engines. In a robust, durable, and low-cost design Optrand pressure sensors utilize the principle of light intensity changes, transmitted by two optical fibers, upon reflection from a specially shaped metal diaphragm deflecting under the effect of pressure. The non-contact detection principle combined with the diaphragm design optimized for infinite fatigue life translates into a sensor with extraordinary lifetime. The sensor's miniature signal opto-electronic conditioner is embedded inside a "smart" electrical connector. Due to its small size and EMI resistance the sensor can be integrated into multi-functional pressure sensing fuel injectors, spark plugs, or glow plugs. The results obtained with almost one thousand of sensors are reported here gathered in gasoline, diesel, and natural gas engines. In the longest application to date, Optrand combustion pressure sensors have demonstrated over 20,000 hours or l billion pressure-cycle service lifetime in large-bore stationary gas engines of pipeline compressor stations. In fuel injection applications the sensor offers typical +7-0.5% accuracy while combustion pressure sensor accuracy is typically in the l- 2% range.