Phasing cylinder pressure to crank angle in a direct injection diesel engine, by simulation of compression curve and elaboration of measured pressure data

When measurements of indicator diagrams are made in an internal combustion engine, the serious problem arises of accurate phasing of pressure data to crank position. This work presents a novel thermodynamic method for such a phasing. A measuring assembly consisting of a piezoelectric transducer, a charge amplifier and a fast data acquisition board installed on a compatible PC computer, is used to obtain the indicator diagrams (i.e. pairs of pressure-time), dispensing thus with the use of a signal from the flywheel TDC marker. An advanced simulation thermodynamic model for the corresponding compression curve (i.e. before fuel injection) is proposed, which includes a detailed zero dimensional energy cascade turbulence submodel for predicting the heat transfer rate between cylinder gas and walls, a blowby rate submodel containing flow calculations in the piston ring pack assembly passages under rings motion conditions, and properties-relations pertaining to real gas (air) behaviour. The measured pressure data are corrected for drift and their exact period (from cycle to cycle) is determined. The theoretical compression curve is shifted (in time) to “coincide” to the compression part (before fuel injection) of the first measured cycle, so that its TDC is determined. The coincidence of the two compression curves is continuously (iteratively) improved by using a double iteration procedure, i.e. by firstly shifting the curves in time and secondly by varying the model’s parameters and calibration constants. After this step, the phasing of pressure data to crank angle of the following cycles can be easily determined, since the corresponding time periods are already accurately calculated. The method is applied with success, under various speed and load conditions, for a fully instrumented single cylinder, LISTER LV1, direct injection, naturally aspirated, Diesel engine installation at the authors’ laboratory.

[1]  Constantine D. Rakopoulos,et al.  Performance and emission characteristics of a diesel engine using supplementary diesel fuel fumigated to the intake air , 1989 .

[2]  Dimitrios T. Hountalas,et al.  Thermodynamic analysis of indirect injection diesel engines by two-zone modeling of combustion , 1990 .

[3]  N. Elsner,et al.  Dr. E. Eckert, Einführung in den Wärme- und Stoffaustausch. Zweite, überarbeitete Aufl. XI + 295 S. m. 171 Abb. Berlin/Göttingen/Heidelberg 1959. Springer-Verlag. Preis geb. 28,80 DM , 1960 .

[4]  Dimitrios A. Kouremenos,et al.  Thermodynamic determination of the top dead centre of diesel engines , 1987 .

[5]  John B. Heywood,et al.  Flow in the piston-cylinder-ring crevices of a spark-ignition engine: effect on hydrocarbon emissions, efficiency and power , 1982 .

[6]  John B. Heywood,et al.  Development and Use of a Computer Simulation of the Turbocompounded Diesel System for Engine Performance and Component Heat Transfer Studies , 1986 .

[7]  T. Muneer,et al.  Mathematical model for calculating the blowby rate , 1981 .

[8]  R Vogt.  THERMODYNAMISCHE BESTIMMUNG DES DRUCKES UND DER WINKELZUORDNUNG BEIM INDIZIEREN VON VERBRENNUNGSMOTOREN , 1979 .

[9]  P. Pinchon.  Calage thermodynamique du point mort haut des moteurs à piston , 1984 .

[10]  John H. Lienesch,et al.  Dynamic Diesel Engine Timing with Microwaves—The General Motors Approach , 1982 .

[11]  W. L. Brown.  Methods for Evaluating Requirements and Errors in Cylinder Pressure Measurement , 1967 .

[12]  Klaus Mollenhauer,et al.  Wärmeübergang in der Verbrennungskraftmaschine , 1977 .

[13]  C. F. Taylor,et al.  The internal-combustion engine in theory and practice , 1985 .

[14]  Constantine D. Rakopoulos,et al.  Ambient temperature and humidity effects on the performance and nitric oxide emission of spark ignition engined vehicles in Athens/Greece , 1988 .

[15]  John H. Lienesch,et al.  Using Microwaves to Phase Cylinder Pressure to Crankshaft Position , 1979 .

[16]  Dimitrios T. Hountalas,et al.  A digital simulation of the exhaust nitric oxide and soot formation histories in the combustion chambers of a swirl chamber diesel engine , 1990 .

[17]  N Watson,et al.  Some Problems in Diesel Engine Research with Special Reference to Computer Control and Data Acquisition , 1976 .

[18]  Dimitrios T. Hountalas,et al.  Thermodynamic analysis of a divided combustion chamber diesel engine , 1988 .

[19]  B. Launder,et al.  Mathematical Models of turbulence , 1972 .

[20]  H. D. Baehr,et al.  Die thermodynamischen Eigenschaften der Luft , 1961 .

[21]  D. A. Kouremenos,et al.  The operation of a turbulence chamber diesel engine with LPG fumigation for exhaust emissions control , 1986 .

[22]  B. W. Millington,et al.  FRICTIONAL LOSSES IN DIESEL ENGINES , 1968 .

[23]  A. Douaud,et al.  DIGITAP-An On-Line Acquisition and Processing System for Instantaneous Engine Data-Applications , 1977 .

[24]  Shoichi Furuhama,et al.  Piston Ring Motion and Its Influence on Engine Tribology , 1979 .