Low Temperature Combustion of Jet Propellant-8 Fuel in Compression Ignition Engine with the Low Compression Ratio

Abstract

Jet Propellant-8 (JP-8) is used as a fuel for a standard Compression Ignition (CI) engine instead of diesel oil, especially in the military applications. The properties of a kerosene-type fuel, which is JP-8, encourage us to test different strategies of mixture creation and combustion, which could be more effective for this fuel than these elaborated for diesel oil. The experiment aimed to show whether it is possible to realise an effective Low Temperature Combustion (LTC) strategy in a CI engine with a low compression ratio for JP-8 fuel. The tests were focused on the combustion of a lean homogeneous JP-8/air mixture close to the knock limit. Additionally, the combustion process of the homogeneous mixtures diluted with EGR was examined. The AVL research engine with a common rail system and low compression ratio (CR = 12) was adapted for the tests. In order to create a homogeneous mixture early, multi injection of JP-8 under high pressure (90 MPa) was applied. The results of the HCCI operation were compared to the Partially Premixed Combustion (PPC) mode without EGR, tested on the same engine with a low CR. The experiment showed that it is possible to realise the LTC process for the HCCI engine fueled with JP-8, though the knock limited the engine load. The application of EGR allowed controlling the phase and rate of the heat release. The higher share of EGR made the HCCI engine cycles less repetitive. Generally, for the HCCI engine operation, the CO and total hydrocarbons (THC) emissions were on a high level. The PM emission was also relatively high, whereas NO x was maintained on a low level for all of the examined points.

The experimental verification of the multi-fuel IC engine concept with the use of jet propellant-8 (JP-8) and its blends with pure rapeseed oil

“…The experiment described in [33] confirmed that it is possible to realize an LTC process for the JP-8 fuel in a CI engine equipped with a common rail system with low CR (12:1), but the HCCI strategy could be applied only for the limited engine load. The results described in this paper show that the active space creation (the first step of HCCI combustion process) and the synchronization of a main dose injection timing with the start of the second stage of quasi-homogeneous mixture combustion (realization of PPC strategy with carefully chosen injection parameters) can be a method of effective fueling of CI engine with a low compression ratio with the use of different fuels.…”

“…Lower octane fuels (such as diesel oil, n-heptane, DME and JP-8) burned in homogeneous charge compression ignition (HCCI) processes exhibit a two-stage ignition [24,33]. The first stage is low temperature heat release (LTHR) or "cool-flame" oxidation reactions (Fig.…”

Emergency fueling unit for means of heavy transport affected by electromagnetic pulse

“…2 ). The phenomenon was also observed in the experiment carried out on the engine with a low compression ratio (CR = 12) fueled with homogeneous mixtures of JP-8 16 . For leaner mixtures, the combustion process was retarded, but the high rate of cylinder pressure rise (dp/dα) was not acceptable.…”

“…The combustion process organisation in the CI engine determines the engine emissions and their efficiency. Despite the development of a homogeneous charge compression ignition (HCCI) process, which is very demanding in terms of combustion control 15 , 16 the CI engine's dominant strategy is Partial Premixed Combustion (PPC) 17 – 19 . Fuel is directly injected into the combustion chamber in PPC mode, and a stratified premixed charge is burned in a controlled way (Fig.…”