The Flex-OeCoS—a Novel Optically Accessible Test Rig for the Investigation of Advanced Combustion Processes under Engine-Like Conditions

Abstract

A new test rig has been designed, built and commissioned, and is now jointly pursued to facilitate experimental investigations into advanced combustion processes (i.e., dual fuel, multi-mode) under turbulent conditions at high, engine-like temperature and pressure levels. Based on a standard diesel engine block, it offers much improved optical access to the in-cylinder processes due to its separated and rotated arrangement of the compression volume and combustion chamber, respectively. A fully variable pneumatic valve train and the appropriate preconditioning of the intake air allows it to represent a wide range of engine-like in-cylinder conditions regarding pressures, temperatures and turbulence levels. The modular design of the test rig facilitates easy optimizations of the combustion chamber/cylinder head design regarding different experimental requirements. The name of the new test rig, Flex-OeCoS, denotes its Flexibility regarding Optical engine Combustion diagnostics and/or the development of corresponding Sensing devices and applications. Measurements regarding in-cylinder gas pressures, temperatures and the flow field under typical operating conditions are presented to complete the description and assessment of the new test rig.

A Specifically Designed Injector for Controlled Lube Oil Addition in View of Investigation of Pre-Ignition Phenomena in Dual–Fuel/Gas Engines

“…devices) test rig located at the Institute of Thermal and Fluid Engineering of the University of Applied Sciences and Arts Northwestern Switzerland. A detailed explanation of the test rig can be found in (Schneider et al, 2020). With its optically accessible cylinder head, pre-ignition phenomena during dual-fuel operation under engine-relevant conditions can be observed and investigated very well.…”

“…Fundamental investigation of pre-ignition based on standard quantities obtained from conventional engine test benches is difficult since necessary information on (turbulent) flow field, evaporation and mixing processes, phase transitions and subsequent reactions (uncontrolled inflammation) can usually not be determined. Thus, application at the in-house available optically accessible engine test facility "Flex-OeCoS" (Schneider et al, 2020) with a possibility of selective lube oil addition (and/or presence of "hot spots") would allow an in-depth examination of the underlying mechanism of the phenomena. Since common fuel injectors are not suitable for this application, because of their hydraulic working principle using high injection pressures, a special injector for controlled lube oil addition had to be developedthe PZDI presented here.…”

Study on the ignitability of a high-pressure direct-injected methane jet using a diesel pilot, a glow-plug, and a pre-chamber

“…Injection was triggered based on the crank angle during the compression stage, as the piston approached top dead center. A more detailed description of the test rig and its basic instrumentation can be found in Schneider et al 37 A detailed description of the sensors used in the test rig has been presented in Humair et al 42 The injector used for the experiments is a prototype derived from a serial heavy-duty diesel injector designed and built for research purposes by Woodward L'Orange GmbH. Figure 4 shows the different sections of the injector.…”

“…In order to study the in-cylinder phenomena of a high-pressure gas jet under engine relevant conditions, the experiments were performed in the Flex-OeCoS optical engine test facility. 37 The adaptable setup of the Flex-OeCoS and its flexible operation modes offer advantageous features for combustion research investigations, as it has been previously used in various projects. 42,43 Figure 1 shows the concept of the experimental facility, in which the cylinders 1, 2, and 4 are deactivated while the working cylinder 3 possesses the instrumented, configurable volume chamber.…”

“…In this work, a novel optically accessible test rig, the Flex-OeCoS, 37 was used to investigate different strategies to ignite a high-pressure direct-injection gas jet. In this setup, a diesel pilot, a conventional glow-plug and a scavenged pre-chamber were used as ignition sources.…”