Number of Cylinders Cylinder Arrangement

3 Inline

4 Inline, flat

5 Inline

12 V, flat (for exotics)

between 70 to 100 mm. Too short a stroke means that there will not be enough torque. The length of the stroke is limited by piston velocities. The minimum displacement of a cylinder can be 250 cc, while the maximum can be up to 1000 cc. The acceptable bore and stroke lengths lead to multiple cylinder engines. The multiple cylinders can be arranged inline, flat, or in a V-shaped configuration, depending on the number of cylinders. The typical arrangements are given in Table 10.1. For a good primary rotational balance, the power strokes of the multiple cylinders are equally spaced. The engine arrangements that have good primary balance are Inline 4 and 6 cylinders, 90° V 8 cylinders, and flat 4 and 6 cylinders. The arrangements that have poor primary balance are 90° V 6 cylinders and Inline 3 cylinders. In the arrangements with poor primary balance, counterrotating balance shafts are used to cancel vibration.

The valve arrangement in the cylinder is known as the valve train. The valve train can be overhead valve (OHV), single overhead cam valve (SOHC), or dual overhead cam valve (DOHC). The OHV has cam, push rod, rocker, and valve; the SOHC has cam, rocker, and valve; while the DOHC has cam, rocker, valve, cam, and valve. There can be 2, 3, 4, or 5 valves in a cylinder. The number of valves selected depends on the trade-offbetween flow and complexity.

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