Effect of HVO CNG dual-fuel operation mode on emissions and performance of CI engine

Abstract

The presented paper aimed to investigate the base effect of the application of HVO (hydrotreated vegetable oil) and CNG (compressed natural gas) and their mixtures as a fuel in the CI (compression ignition) engine. Both fuels were then used in the dual-fuel operating mode (HVO-CNG). Dual-fuel applications are usually made with a liquid fuel (diesel) pilot dose and gaseous fuel (LPG, CNG etc.) main dose. In times of reducing greenhouse emission gases and reducing the dependency on Russian gas and oil, it should be possible and technically possible to reduce both of them in several engine machine applications. As an ecological substitute for diesel oil hydrotreated vegetable oil is used and as an ecological substitute for compressed natural gas biomethane should be used. All experiments were done on a four-stroke direct injection turbocharged CI engine with an installed AC STAG electronic control unit and system for the dual-fuel operating mode. The whole setup was installed on a test bed equipped with ac dyno (which also allows running transient tests) and with other external measurement devices. For the high-pressure indicating parameters, AVL X-ion was used (with an Indicom SW). Horiba mexa-one device was used for gaseous emission measurement. For particulate matter measuring, Horiba SPCS counter was used and Horiba MDLT-One dilution tunnel and TSI EEPS as the particle sizer. As a base level, parameters were set and used for performance and other parameters (emissions, burning, knocking etc.) from the diesel operating mode. All other operating modes were then compared to the base level.