Five-stroke Internal Combustion Engine - yesterday, today and tomorrow

Comprehensive Review of Innovation in Piston Engine and Low Temperature Combustion Technologies

“…Throughout history various approaches to improve the Otto cycle have appeared (Noga, 2018). Even today the Atkinson and Miller cycles have their place in propulsion systems with the goal to achieve higher efficiency by means of changing the ratio of the expansion and compression stroke of the standard Otto cycle (Kéromnès et al 2014;Li et al 2016).…”

“…Driven by this notion various over-expanded engines are once again under development (Arabaci et al 2015;Li et al 2015;Noga, Sendyka 2014;Palanivendhan et al 2016). These 5-or 6-stroke engines feature extra strokes within the engine cycle to reduce losses in the engine by utilising waste heat but are by no means a novel idea having been development since the birth of the 1st ICE (Noga 2018). These historic attempts were sadly constrained by the limitations of the technology at the time, but today's scientist have new materials and resources at their disposal that enable a new attempt at developing a functional over-expanded engine.…”

“…A modernised 5-stroke engine was patented by Schmitz and has been simulated but also built and tested by multiple research teams (Noga 2018). In the 5-stroke engine of Schmitz (2003) the additional expansion of gases is achieved through directing the exhaust gases of a fired cylinder to a separate cylinder.…”

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

“…Such engines were already being constructed by the end of the 19 th century, and they were modelled on steam machines with a multipleexpansion process. At the time, such engines were called "compound engines" in English, "moteur compound" in French and "Verbundmotor" in German [35]. Nowadays, the term "five-stroke engine" is most commonly used to describe this type of engine; the term comes from the fifth stroke of additional charge expansion preceded by a classic four-stroke cycle.…”

“…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.…”