Fig. 2.20. Valve mechanism of Mazda 3 engines: 1 – camshaft; 2 - timing gear drive chain; 3 – camshaft sprocket; 4 – tensioner lever; 5 – chain tensioner; 6 – crankshaft pulley; 7 – chain guide; 8 – valve unit; 9 – cam; 10 – Oil control valve (OCV); 11 – actuator of the variable valve timing system
Each cylinder has two intake and two exhaust ports. 16 valves are directly actuated by two camshafts. The L3 engines use a variable valve timing mechanism, which provides the best valve opening or closing moment, depending on driving conditions, by constantly changing the phases of the intake camshaft (Fig. 2.20).
Fig. 2.21. Diagram of opening and closing of the valve of Mazda 3 engines: 1 – TDC; 2 – variable area; 3 – release; 4 – inlet; 5 – BMT
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