Analysis of Combustion and Particulate Emissions when Hydrogen is Aspirated into a Gasoline Direct Injection Engine 2010-01-0580
A single-cylinder Gasoline Direct Injection Engine (GDI) engine
with a centrally mounted spray-guided injection system (150 bar
fuel pressure) has been operated with stoichiometric and rich
mixtures. The base fuel was 65% iso-octane and 35% toluene;
hydrogen was aspirated into a plenum in the induction system, and
its equivalence ratios were set to 0, 0.02, 0.05 and 0.1. Ignition
timing sweeps were conducted for each operating point.
Combustion was speeded up by adding hydrogen as expected. In
consequence the MBT ignition advance was reduced, as were
cycle-by-cycle variations in combustion. Adding hydrogen led to the
expected reduction in IMEP as the engine was operated at a fixed
manifold absolute pressure (MAP). An engine model has also been set
up using WAVE.
Particulate Matter (PM) emissions were measured with a
Cambustion DMS500 particle sizer. The effect of ignition timing on
the PM emissions was marked - retarding the ignition led to a
substantial reduction in the PM number emissions, especially for
the nucleation mode. Overall, retarding the ignition could lead to
more than an order of magnitude reduction in particle number for
stoichiometric combustion. For the MBT ignition timing, adding a
hydrogen equivalence ratio of 0.1 led to more than an order of
magnitude reduction in both the PM number and mass for
stoichiometric and rich (lambda = 0.9) combustion.