Abstract:Abstract. The paper presents the theoretical basis and practical implementation of the concept of a five-stroke cycle where an additional expansion of the working medium is achieved in a separate cylinder. The work, carried out at the Cracow University of Technology, constitutes a development of the idea of five-stroke engine. This paper proposes a new theoretical thermodynamic cycle that describes the processes occurring in a five-stroke engine. It has been taken into consideration that the expansion ratio of… Show more
“…Since the engine was designed for the range extender application, the full load limit was defined as the point of drastic increases of fuel consumption with increasing torque, and a regular turbocharger could be employed. Noga et al [31,32] studied both theoretically and experimentally the similar concept to the five stroke cycle engines with the total expansion ratio twice than the compression ratio. They modified a four-cylinder four-stroke engine into a five stroke engine with remaining the outer two cylinders working with conventional four-stroke cycle and the inner two cylinders working only with expansion and exhausting strokes.…”
“…Since the engine was designed for the range extender application, the full load limit was defined as the point of drastic increases of fuel consumption with increasing torque, and a regular turbocharger could be employed. Noga et al [31,32] studied both theoretically and experimentally the similar concept to the five stroke cycle engines with the total expansion ratio twice than the compression ratio. They modified a four-cylinder four-stroke engine into a five stroke engine with remaining the outer two cylinders working with conventional four-stroke cycle and the inner two cylinders working only with expansion and exhausting strokes.…”
“…The basic technical specifications of the engine with additional expansion of exhaust gases developed at Cracow University of Technology in its current configuration are shown in Table 1. The engine developed at Cracow University of Technology was the subject of several previous studies [34][35][36][37] and [39][40][41]. These works focused mainly on aspects related to the description of the design itself in which the engine was constructed on the basis of an existing four-stroke engine, issues of the thermodynamic description of processes occurring in it and the analysis of engine test results in the context of its thermal and mechanical efficiency indicated the mean effective pressure and the ratio of exhaust energy recovery in cylinders of additional expansion.…”
Section: Brief Description Of the Engine And The Motivation For Aftermentioning
This paper presents the results of research on the development of an exhaust gas aftertreatment system for a turbocharged five-stroke engine. This engine was designed and constructed at Cracow University of Technology. A characteristic feature of the five-stroke engine is the use of an additional expansion process to increase overall efficiency. A challenge for a catalytic converter is the fact that it has a low exhaust gas temperature. Two three-way catalytic converters were tested-one with a ceramic support and the second with a metal support. The results of the tests showed that the reactor with a ceramic support obtains an acceptable conversion efficiency starting with an exhaust gas temperature of 280°C. For the metal-support reactor, a few percent increase in torque and a decrease in the brake-specific fuel consumption of the engine was obtained; however, the converter itself did not show signs of operation even with an exhaust gas temperature of over 380°C. The performed analyses highlighted directions of further development works in this area.
“…During the development of the engine with the additional expansion of exhaust gas, a thermodynamic cycle taking into account the specific characteristics of the tested engine was proposed [17]. Extensive simulation studies of a similar engine, but with a single-cylinder of additional expansion, was also carried out by Li et al at Shanghai Jiao Tong University [18,19].…”
Section: Five-stroke Engine Developed At Cracow University Of Technologymentioning
Abstract:The paper presents the results of research on the turbocharged spark ignition engine with additional exhaust expansion in a separate cylinder, which is commonly known as the five-stroke engine. The research engine has been constructed based on the four cylinder engine in which two outer cylinders work as the fired cylinders, while two internally connected inner cylinders constitute the volume of the additional expansion process. The engine represents a powertrain realizing an ultra-expansion cycle. The purpose of the study was to find an effective additional expansion process in the five-stroke engine. Cylinder-pressure indicating measurements were carried out for one of the fired cylinders and the additional expansion cylinder. The study was performed for over 20 different points on the engine operation map. This allowed us to determine a dependence between the pressure indicated in the fired cylinders and in the additional expansion cylinders. A function of the mean pressure indicated in the additional expansion cylinder versus a brake mean effective pressure was also presented. This showed a load threshold from which the work of the cylinders of additional expansion produced benefits for the output of the experimental engine. The issues of mechanical efficiency and effective efficiency of this engine were also discussed.
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