increase can be mainly attributed to the well known HC emissions reduction with

Increase can be mainly attributed to the well known

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increase can be mainly attributed to the well-known HC emissions reduction with biodiesel fuelling in such a way that NO oxidation inhibition is lower [9]. In fact, as a numerical model [10] has also demonstrated, the slight different inlet thermal conditions (mass flow rate and temperature) between the blends don’t influence that behavior.
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The transient results confirm that B30 gives a higher conversion efficiency, as it is shown in Figure 1. Fig. 1. Steady state (left) and transient (right) NO-NO2 conversion efficiency of the DOC 3.3. DPF loading and regeneration processes During the transient engine tests, PM concentration has also been measured in order to understand the biodiesel combined effects on both engine-out PM reduction and NO2 increase at DPF inlet. Indeed a low PM/NO2 ratio can enhance passive DPF regeneration and thus ensure fuel consumption reduction. The analysis of average emissions highlights a 26% PM reduction for B30 with respect to B06. Moreover, the increased NOx emissions (+5%) combined with an increased NO2/NOx ratio (+23%) allows for a total 44% reduction of the PM/NO2 ratio for the B30 blend. This measured parameter can be one of the factors which gives the non linear trend of the B30 DPF backpressure curve of Figure 2, measured during the transient 3-4h period, and that can be related to an enhanced reduction of the trapped PM.
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Fig. 2. DPF backpressure curves for the two blends measured during transient tests Furthermore, the experimental validation of an in-house numerical model [4] has highlighted that, although the lower PM/NO2 ratio could have enhanced trapped mass reduction, the main factor has to be attributed to a reduction of the activation energy of the passive regeneration. This result – a higher B30 soot reactivity – has been confirmed by a preliminary thermo gravimetric analysis (TGA) of the PM emitted by the two blends [4]. This higher reactivity of the PM emitted by biodiesel combustion has also been confirmed in the literature [11, 12] and is currently under investigation. 4. Conclusions In this paper several engine tests have been carried out to analyze biodiesel fuelling effects on engine performances and emissions and the Aftertreatment System behavior. A numerical model has been developed and validated in order to understand the main factors affecting the mentioned variations. The lower heating value of biodiesel can be considered the main reason for the higher BSFC of the B30 blend and the slightly higher NOx emissions, while its higher oxygen content the one for the PM reduction. Both the combination of the biodiesel effect on PM reduction and increased DOC conversion efficiency can enhance passive DPF regeneration. Moreover, a higher PM reactivity should be taken into account as the main factor in order to explain the significantly higher DPF trapped mass reduction in the B30 case.
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Jurnal 2 Pembuatan Biofuel dari Minyak Goreng Bekas Melalui Proses Catalytic Cracking dengan Katalis Fly Ash Abstrak Minyak bumi adalah bahan bakar fosil yang tidak dapat diperbarui tetapi semakin berkurang ketersediaannya. Biofuel adalah energi alternatif terbarukan
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  • Spring '13
  • DAVIS

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