Abstract
Research and /or Engineering Questions/Objective:
Combustion analysis tools using in-cylinder-pressure are primarily used during engine development to calculate engine performance based on a set of standard algorithms. These parameters are used off-line for adapting engine management systems to improve performance, emission and reliability. The objective of this study was to develop both new algorithms and a prototype for calculating parameters like CA50 and IMEP just in time making these available at the end of a combustion cycle. The parameters can be used for e.g. closed loop engine control or diagnostic purposes.
Methodology:
Standard literature lists a number of algorithms for calculating engine performance parameters like CA50 and IMEP. The algorithms described in literature for calculating these parameters suggest that a pressure curve of a full combustion cycle is available before being analysed. Algorithms have been modified to calculate engine performance parameters while data is being acquired to have the result available when a combustion cycle is finished. Development of a prototype was required to demonstrate that the approach works for operating conditions up to 6000 RPM. The prototype includes a Field Programmable Gate Array for parallel digital signal processing. Simulation and comparison to a commercial tool was used for validating the results
Results:
The paper presents a new way for implementing algorithms for calculating CA50 and IMEP. It also describes the hardware and software architecture of the prototype built to demonstrate this approach. A prototype has been built to implement the algorithms and check the performance. A test setup based on a commercial diesel engine and mass produced cost effective glow plug pressure sensors was used to demonstrate the prototype up to 4000 RPM.
Limitations of this study:
The study currently only covers diesel engines, and analysis of a single cylinder. Current validation only covers fixed RPM operating conditions. What does the paper offer that is new in the field in comparison to other works of the author: A very fast analysis method and prototype are presented for calculating CA50 and other engine performance parameters based on in-cylinder-pressure.
Conclusion:
Just in time calculation of CA50 and IMEP based on in-cylinder pressure is feasible. - Results are made available at the end of a combustion cycle - Prototype works up to 4000 RPM on real-life diesel engine, 6000 RPM using HW in the loop simulation. - Computed results for CA50 are accurate up to 1 CAD. - FPGA technology is well suited for signal processing of pressure sensor data. - Mass produced cost effective pressure sensors can be used for real-time CA50 monitoring.
KEYWORDS – Engine performance, Real-time, CA50, in-cylinder pressure, FPGA.