Comparison of Primary and Secondary Emissions from an Internal Combustion Engine - Novel Combustion Concepts for Sustainable Energy Development - page 419

Fig. 9 Values of total toxic
equivalent potentials with
respect to engine load for
primary and secondary
exhaust fuelled with diesel
and B20 (adapted from
Agarwal et al. 2013 )

compared to B20 for both primary and secondary particles. Primary and secondary
particles TEFs for diesel was higher at 100 % engine load. Overall TEFs were 509
and 381 for diesel and B20 (primary particles), respectively, at 100 % engine load.
TEFs were 1,547 and 1,130 for diesel and B20 (secondary particles), respectively,
at 100 % engine load. B20 predominantly has individual PAHs with relatively
lower toxicity. B20 particulates had signi cantly enhanced PAHs loading while

their contribution to overall toxicity was far lower as compared to those from
mineral diesel.

6.4 Primary and Secondary Particulates Emission

Primary emission particles were carefully collected over 47 mm diameter quartz

cant
collection of particles was noticed at the no load condition (Fig. 10 ). This maybe
due to the fact that at no load conditions, most of the nuclei mode particulates are
formed and nearly no contribution from EC (Zielinska et al. 2003 ). Due to the light
colored OC dominantly present over the

filter papers after diluting the exhaust with HEPA filtered clean air. No signi

filter, they may have completed masked
the tiny EC present in the sample. Also, the white filter background did not helped

in providing the right contrast needed for such images. Aged particulate collection
was wet in nature when compared to primary exhaust particulates measured over

filter paper (Fig. 10 ). For low and intermediate engine loads (25 and 50 % load) a
signi cant amount of particles got collected. Aged particles were wet, denser and

bigger (coagulation and aggregation) than the primary particles (Agarwal et al.
2013 ).