Engines, internal combustion fuel characteristics

Catalyst-poisoning studies have concentrated on the potential poisons introduced with fuel, particularly on lead, which has been added intentionally to improve the combustion characteristics at the high compression ratios employed in modem internal combustion engines prior to the introduction of exhaust purification catalysts. The lead is usually introduced as motor mix which contains tetraethyllead in a mixture with organic halides, chlorides or bromides. These halides transport the lead in the form of volatile halides out of the engine and into the exhaust, and are hence termed lead scavengers. Thus the potential catalyst-poison elements associated with the additive mixture are Pb, Br, and Cl. 

The carbon residue (ASTM D-189 and ASTM D-524) of a crude oil is a property that can be correlated with several other properties (Figure 2-14). The carbon residue presents indications of the volatility or gasoline-forming propensity of the feedstock and, for the most part in this text, the coke-forming propensity of a feedstock. Tests for carbon residue are sometimes used to evaluate the carbonaceous depositing characteristics of fuels used in certain types of oil-burning equipment and internal combustion engines. 

A fuel cell can be thought of as a cold-combustion power source that generates electrical energy directly from (stored) chemical energy. Due to minimal heat transfers, it is unfettered by conversion-efficiency hmitations characteristic of hot-combustion devices. Unlike batteries, but similar to internal combustion engines, a fuel cell is a continuous-flow system in which fuel and oxidant are externally supplied for operation. In a functional hydrogen-fuel cell, H2 gas is introduced through feed plates to the anode compartment. At the same time, but to the cathode in a separate chamber, O2 gas delivered. At the anode, H2 is oxidized to H ... 

Distributed power generation is a required component of a CHP system. Internal combustion engines, combustion turbines, and fuel cells are the current prime movers that have the most potential for DPG. Characteristics of these DPG technologies such as electric efficiency, power output, and cost are presented in Table 3. 

The fuel cell is most efficient at small loads. The efficiency decreases as the load increases and it is least efficient at full load. Because of this characteristic, the fuel cell operates efficiently under the most common driving conditions of partial load. The fuel cell drive system can deliver the same power to the wheels at zero revolutions per minute as at high speeds. Because of these relationships, the fuel cell is better suited as an automobile power source than is the internal combustion engine. 

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