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Energy & Fuels 2005, 19, 418-425
Dual Fuel Diesel Engine Operation Using H2. Effect on Particulate Emissions A. Tsolakis,† J. J. Hernandez,*,‡ A. Megaritis,† and M. Crampton§ School of Engineering, Mechanical and Manufacturing Engineering, The University of Birmingham, Birmingham B15 2TT, United Kingdom, Universidad de Castilla-La Mancha, Edificio Politecnico, Escuela Tecnica Superior de Ingenieros Industriales, Avda. Camilo Jose Cela S/N, 13071 Ciudad Real, Spain, and School of Geography, Earth and Environmental Sciences, The University of Birmingham, Birmingham B15 2TT, United Kingdom Received June 2, 2004. Revised Manuscript Received November 3, 2004
In recent publications, the authors have shown that the exhaust gas fuel reforming technique has the potential to provide a way of controlling diesel engine exhaust emissions. The technology involves the incorporation of a reformer in the engine exhaust gas recirculation (EGR) loop. Fresh fuel is injected in the reactor, where it is reformed by catalytic reaction with exhaust gas. The produced hydrogen-rich gas is then fed back into the engine as reformed EGR (REGR). Thus, in this way, the engine in effect operates in dual fuel operation mode. In the present study, the particulate emissions of the diesel-hydrogen fueled engine were studied using an electrical low pressure impactor (ELPI). The work was performed by simulating the operation of an optimized engine-reformer system by feeding the engine with simulated reformate containing 24% hydrogen. The particle size and mass distribution were not affected significantly, but the particle total number and mass were reduced considerably, compared to the standard diesel fueling.
Introduction The wide use of the diesel engine as a power source in on-road heavy-duty vehicles, off-road power generation, and marine applications, as well as the growing market share of diesel high-speed passenger cars in recent years is due to good engine performance, reliability, durability, better fuel consumption, and lower CO2 emissions. However, the diesel engine is a significant source of particulate matter (PM) and NOx emissions, primarily because of the nonhomogeneous combustion process. The particles destined to be emitted as PM are born as soot nuclei in the highly oxygen-deficient core of fuel sprays. Particulates are formed in the cylinder in the locally rich regions of the inhomogeneous combustion. Subsequently, the soot burns at the boundary of the diffusion flame sheath, because of the available oxygen and high temperatures.1 Many researchers have reported that diesel particulates can have severe effects on human health, and they are classified as probable carcinogens to humans.2-4 There are strong suggestions that the number and size
of the particulates may be more relevant for human health effects than the mass.5 In fact, the smaller particles have a higher probability to be inhaled and deposited in the respiratory tract and in the alveolar region by diffusion, and such particles are more likely to cause respiratory diseases, as well as inflammation and damage to the lungs. Toxicological studies have shown that fine particles with aerodynamic diameters of
