Page 119 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

2
Engine systems 103

Figure 2.37 Cylinder layouts and power strokes per engine revolution

4 cylinder in-line ‘V’ 2 cylinder
horizontally opposed

Overhead cam (OHC) petrol engine with Overhead valve (OHV) diesel engine with
hemispherical combustion chamber bowl in piston combustion chamber

Figure 2.38 Engine designs

2.1.2.4 Engine design variations
The following section outlines some of the many design variations that are or
have been used for engines. The confi guration of the engine depends on the
number of cylinders, their relative position, the engine layout and the fi ring
order, as well as combustion chamber design, fuel type, valve train design,
engine location and mounting position. Further parameters are engine type
(reciprocating, rotary) and stroke (two or four).

The simplest engine design is the single cylinder, normally found in small engine
applications ( Fig. 2.39 ). If the engine is a single-cylinder four-stroke, then the
engine fi res only once every other engine revolution. This gives a large variation
in the torque delivery at the engine crankshaft and hence torsional vibration is
signifi cant and the engine is not very smooth. Increasing engine capacity does
not increase power output directly as there are other factors that contribute to
the effi ciency of the engine (heat and pressure losses); therefore, there is an