Measuring Absolute-Cylinder Pressure and Pressure Drop Across Intake Valves of Firing Engines

Puzinauskas, Paulius V.; Eves, Joseph C.; Tillman, Nohr F.

doi:10.4271/941881

Cited by 7 publications

(2 citation statements)

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“…Piezo-electric transducers are appropriate for cylinder-pressure measurement because they have a high frequency response, a small size, and accurate, linear response; however, during operation they are affected by thermal transients including thermal shock. 3 Thermal shock is generated when rapid changes in temperature, caused by the arrival of the flame, vary the Young's modulus and resonant frequency of the quartz crystal and cause the expansion or contraction of the diaphragm. 4 Thermal shock in combustion-pressure measurements has been shown to far exceed 50 kPa and affects the measurement through the exhaust stroke and into and sometimes beyond the intake stroke.…”

Section: Introductionmentioning

confidence: 99%

“…4 Thermal shock in combustion-pressure measurements has been shown to far exceed 50 kPa and affects the measurement through the exhaust stroke and into and sometimes beyond the intake stroke. 5 This error affects the accuracy of all the previously listed parameters of interest, under all engine-operating conditions. In particular, thermal shock makes the pumping process measurements useless at moderate-to-high engine load given that the error can be on the order of half the cylinder pressure during the intake and exhaust process.…”

Section: Introductionmentioning

confidence: 99%

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Advanced Laboratory for Image and Video Engineering

Akers¹

2000

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The objective of this project is to characterize engine-combustion-pressure measurement errors caused by flame induced transducer thermal stress. Thermal shock measured in an engine flame simulator was compared to data from a running engine. The engine-flame simulator impinged an oxygen-acetylene flame on a pressure transducer at atmospheric pressure. At constant pressure, any change in the transducers output can be attributed to thermal shock. This identifies the exact instant at which thermal shock begins and the start of its subsequent recovery.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Advanced Laboratory for Image and Video Engineering

Akers¹

2000

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In-Cylinder Pressure Measurement: Requirements for On-Board Engine Control

Ponti

2008

Journal of Engineering for Gas Turbines and Power

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During these last years, passenger vehicles have been equipped with an increasing number of sensors, in an effort to monitor and control their behavior in terms of global performance and emissions. This, together with constantly increasing electronic control unit computing power and data storage capabilities, allowed the development of more efficient engine-vehicle control strategies. In this perspective, new sensors will be employed as soon as their use will be shown to be necessary to design new engine control and diagnostic strategies, and their cost and expected life will be compatible with on-board application. A sensor that has been largely studied in recent years is the in-cylinder pressure one: advanced engine control strategies that make use of the signal coming from such a sensor have been investigated, while reliable and low-cost sensors are being developed to survive for the vehicle life the harsh on-board environment. The signal coming from the in-cylinder pressure is, in fact, very rich in information and could be used, for example, to improve engine torque management (by directly computing the instantaneous indicated torque), to improve air∕fuel ratio control, misfire and knock detection capabilities, engine emission estimation (to be used for DeNOx catalysts purging management as an example), residual gas fraction estimation, etc. Many sensor concepts have been developed, although none seems to actually fully meet both the precision and low-cost requirements necessary for on-board application. This work deals with defining the sensor precision characteristics necessary to effectively implement the aforementioned engine control and diagnostic capabilities improvements. In particular, it will be shown that only the low-frequency signal content has to be precisely measured and is critical for certain application. In addition, the importance of a correct reference of the in-cylinder pressure signal is discussed, and a novel methodology to quickly obtain this information once the engine has been setup with a proper in-cylinder pressure sensor is discussed.

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