Combustion improvement in a hydrogen fueled engine

Lean Hydrogen Combustion

“…Therefore, determining the mechanism of preignition, practical operational limits, and control strategies has been a primary focus of many research studies (e.g., Furuhama et al, 1977;Swain et al, 1981;Binder and Withalm, 1982;Kondo et al, 1997;Li and Karim, 2004;Maher and Sadiq, 2004). Unfortunately, despite much effort, there exist no guaranteed preventive steps.…”

“…Unfortunately, despite much effort, there exist no guaranteed preventive steps. However, identification of preignition sources, such as in-cylinder hot-spots (Furuhama et al, 1977;Tang et al, 2002), oil contaminants , combustion in crevice volumes (Lee et al, 2001), and residual energy in the ignition system (Kondo et al, 1997), has provided the necessary minimizing steps. These include use of cold-rated spark plugs, low coolant temperature, and optimized fuel-injection timing.…”

“…Advanced control strategies include intake charge cooling (Fiene et al, 2002), variable valve timing for effective scavenging of exhaust residuals (Berckmüller et al, 2003), advanced ignition systems (Kondo et al, 1997), and hydrogen direct injection (DI) (Furuhama et al, 1977;Homan et al, 1983). These advanced strategies can be quite effective: Berckmüller et al (2003), employing a single-cylinder 0.5-L PFI-H2ICE at a CR of 12:1, used variable cam phasing and computational fluid dynamics (CFD) simulations to optimize coolant flow, injection location, and injection timing to operate at f ¼ 1 over a speed range 2000-4000 rpm.…”

Investigation of the combustion process of hydrogen jets under argon-circulated hydrogen-engine conditions

“…Although hydrogen can be stably utilized using super-lean fuel mixtures, lean operations can significantly reduce the power output because of reductions in the volumetric heating and the low energy density of hydrogen in air-fuel mixture [15] . Furthermore, the low ignition energy of hydrogen can cause abnormal combustion, such as backfiring, pre-ignition, and knocking; these effects are the primary obstacles to the operation of hydrogen premixed charge SI engines, in addition to their low output [12][13][14][15] . These issues can be resolved by directly injecting the fuel gas into the cylinder.…”

“…Various studies have focused on combustion improvements for hydrogen fuel [12] , the influence of the injection timing under various equivalence ratios [13] , and knocking in SI engines [14] . Although hydrogen can be stably utilized using super-lean fuel mixtures, lean operations can significantly reduce the power output because of reductions in the volumetric heating and the low energy density of hydrogen in air-fuel mixture [15] .…”