Various aspects of research of the SI engine with an additional expansion process

Abstract

Abstract. The paper presents an analysis of the results of the both experimental results and theoretical works on the SI engine with additional expansion of exhaust gases, also known as five-stroke engine. The engine like this was constructed at Cracow University of Technology as a retrofitted in-line four cylinder engine in which outer cylinders (1st and 4th) work as fired cylinders and inner cylinders (2nd and 3rd) work as volume for the additional expansion. The aim of development of such an engine is to gain higher energy recovery ratio of the combusted fuel through the second expansion of exhaust in a separate cylinder. The operating parameters of the engine in various versions were analyzed: as naturally aspirated, supercharged using a turbocharger with a waste-gate valve and a turbocharger with variable nozzle turbine. Selected results of the indicating measurements of the engine with special emphasis on the indicated thermal efficiency were presented. The results pointed out the directions of further optimization of the engine. These results are all the more important, because according to the author's knowledge, the research on the real object of this type are carried out in only one science center in the world besides Cracow University of Technology.

A three-way catalyst system for a five-stroke engine

“…In brief, the use of the process of additional expansion of exhaust gases is the more beneficial, the higher the temperature and pressure at the end of the main expansion process are. With a properly conducted combustion of the stoichiometric mixture these will depend on the amount of charge delivered to the cylinder [36,37]. In practice, the restriction is the increase in the exhaust gas pressure upstream from the turbine resulting from the increase of the required boost pressure.…”

“…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.…”

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“…1. [7,9,10,12,13] and dissertation [14]. In the recent years simulations of operation of the similar engine are also conducted at the Shanghai Jiao Tong University by Li et al [15].…”

“…Technical data of the tested engine[10,11] EVC additional exp. cylinders 28° BBDC / 8° BTDC Various tests of the engine developed at the Cracow University of Technology were made.…”

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“…According to the same prognosis, a significant proportion of the remaining vehicles will have hybrid propulsion systems, in which apart from the internal combustion engine, an electric motor can usually be found. Internal combustion engines are still being developed; however, it is clear that over the course of dozens of years, the electric drive will be a replacement for the internal combustion engine in automotive applications [12]. The basic advantage of replacing propulsion from combustion engines in the automotive sector with the electric drive is their zero emission of toxic gases at the place of their use.…”