Sunday, October 20, 2013
What Is a Heat Crossover
An internal combustion engine produces plenty of heat. While this heat is a potentially destructive factor, the heat crossover puts some of it to good use.
Exhaust Manifolds
Gasoline burns in structures called cylinders, usually six or eight in number. Half of the cylinders lie on the left side of the engine, the other half on the right. Little exhaust pipes lead from each cylinder to the main exhaust system. Collectively these pipes are called the exhaust manifold. Some cars have two exhaust manifolds, one on each side of the engine. The right exhaust manifold collects exhaust gases from the cylinders on the right side of the engine while the left exhaust manifold collects exhaust gases from the cylinders on the left.
Fuel Delivery System
The carburetor lies in the center of the engine between the two sets of cylinders. The carburetor mixes the fuel with air and sends the mixture to the two sets of cylinders through a delivery system that includes a chamber called the plenum and an intake manifold consisting of pipes to each cylinder.
Heat Crossover
Some car engines have an extra passage in the intake manifold called a heat crossover. It leads from the exhaust manifold on one side of the engine to the exhaust manifold on the other side, passing the carburetor and the plenum en route. Some of the hot exhaust gases pass through this heat crossover before exiting through the exhaust system. As these gases pass by, the heat of the exhaust gas warms the carburetor and plenum. Consequently, the injected fuel vaporizes better. This is especially helpful when the car first starts and the engine is still cold..
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