OHV Engine Model

The engine with this design of the bottom camshaft is generally a large displacement, low speed, and the pursuit of high torque output, because the bottom camshaft is driven by the crankshaft, and then the cam and the valve rocker arm are connected by a metal rod. The cam lifts the connecting rod, and the connecting rod pushes the rocker arm to realize the opening and closing of the engine valve, so the excessively high speed will cause the ejector rod to bear too much pressure and break. However, this design with ejector also has its advantages, such as simple structure, high reliability, bottom center of gravity of the engine, and low cost. Because the engine speed is low, the emphasis is on torque performance, so the bottom camshaft design is sufficient to meet this demand.

 Japanese and European car manufacturers prefer the overhead camshaft design; while the bottom camshaft is usually only seen on American cars.
Why only Americans love bottom camshafts?
In Germany, where the automobile industry is developed, many highways have no speed limit, and speeding at a speed of more than 200 kilometers is a common thing. Therefore, high power is naturally their favorite. But Americans are different, they are after highway cruising performance, the engine does not need a high speed. This has a lot to do with the national conditions of the United States. The United States has a large land and abundant resources, and most of them are plains. The roads are built straight and straight. After World War II, Americans have always been keen on luxury cars with unique shapes, spaciousness, and emphasis on comfort. Such cars usually The weight is large, the suspension is soft, the comfort of straight-line driving is very good, and the oil price in the United States is very low, and the large-displacement engine is very popular among the people. Therefore, the popularity rate of this engine with 6.0 and 7.0 is very high. Speaking of which, it must be added that we often talk about engine liters of power, and use this to determine the operating efficiency of the engine. But have you ever heard the term power density? The concept is simply to release the same power, the smaller the volume of the engine, the higher the power density. The engine with the bottom camshaft benefits from its low rotation and high torque, and does not require the complicated arrangement of multiple valves, double camshafts, and high-strength cylinder head covers like the overhead camshaft.