211 Two Stroke versus Four Stroke

All engines go through four cycles: intake, compression, power, and exhaust. Engines can be either two stroke or four stroke. In two-stroke designs, the four cycles are completed during each complete revolution of the crankshaft. Therefore, there is a power stroke during each revolution. In four-stroke designs, the four cycles are completed every two revolutions of the crankshaft; there is a power stroke only every other revolution of the crankshaft. For this reason, two-stroke engines have higher power density than four-stroke engines. However, because the intake and exhaust functions do not achieve completion, the two-stroke engine is not as efficient as a four-stroke engine and has higher emissions.

FIGURE 2.3

Crossection of ICE showing from top to bottom: turbochargers, intake manifold, pistons and cylinders, connecting rods, crankshaft, and oil sump (courtesy of Caterpillar, Inc., with permission).

FIGURE 2.4

Induction and combustion chamber detail. (Reprinted from EGSA's On-Site Power Reference Book, 3rd ed., 1998, with permission. All rights reserved.)

FIGURE 2.4

Induction and combustion chamber detail. (Reprinted from EGSA's On-Site Power Reference Book, 3rd ed., 1998, with permission. All rights reserved.)

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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