The engine out particular matter number (PN) distributions at engine coolant temperature (ECT) of 0 o C to 40 o C for ethanol/ gasoline blends (E0 to E85) have been measured for a direct-injection spark ignition engine under cold fast idle condition. For E10 to E85, PN increases modestly when the ECT is lowered. The distributions, however, are insensitive to the ethanol content of the fuel. The PN for E0 is substantially higher than the gasohol fuels at ECT below 20 o C. The total PN values (obtained from integrating the PN distribution from 15 to 350 nm) are approximately the same for all fuels (E0 to E85) when ECT is above 20 o C. When ECT is decreased below 20 o C, the total PN values for E10 to E85 increase modestly, and they are insensitive to the ethanol content. For E0, however, the total PN increases substantially. This sharp change in PN from E0 to E10 is confirmed by running the tests with E2.5 and E5. The midpoint of the transition occurs at approximately E5. Because the fuel evaporative property does not change substantially from E0 to E10, the significant change in PN is attributed to the particulate matter formation chemistry.

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Kar, K et al. "Organic gas emissions from a stoichiometric direct injection spark ignition engine operating on ethanol/gasoline blends."

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This paper presents a novel work on localization of transmitters using triangulation with sensors at fixed positions. This is achieved when three or more sensors cover the whole area, a factor which enables the system to perform localization via triangulation. The network needs to keep a high detection rate which, in most cases, is achieved by adequate sensor coverage. Various tests using various grids of sensors have been carried out to investigate the way the system operates in different cases using a lot of transmitters. Detection complexity is tackled by finding the optimal detecting sensor radius in order for the network to continue operate normally. The coverage quality changes in the area of interest and the network is able to detect new transmitters that might enter the area of interest. It is also shown that as the number of transmitters increases the network keeps its high performance by using additional groups of sensors in a sub-region area of that of interest. This way, even when the network is saturated by many transmitters in one region, new transmitters can still be detected.