Cylinder head and gasket
The cylinder head is made of aluminum alloy. The cylinder head has intake and exhaust channels on opposite sides. The spark plug is located in the center of each combustion chamber. The cylinder head contains double camshafts.
Crankshaft
The crankshaft has integral counterweights molded with it for balance. Oil holes run through the center of the crankshaft and supply oil to connecting rods, bearings, pistons and other parts. The axial load is taken up by thrust washers mounted on the central journal.
The drive belt of the gas distribution mechanism
The timing belt coordinates and synchronizes the rotation of the crankshaft and dual overhead crankshafts. The timing belt also drives the coolant pump. The timing belt and pulleys are toothed to prevent slippage between them. There are two idle pulleys. The automatic tensioner ensures that the timing belt is properly tensioned. The timing belt is made of durable reinforced rubber, similar to the rubber used for the flex belt. The timing belt does not require lubrication.
Oil pump
The oil pump draws engine oil from the oil pan and supplies it under pressure to various parts of the engine. An oil filter is installed upstream of the oil pump inlet to remove contaminants that could clog or damage the oil pump or other engine components. When the crankshaft rotates, the driven gear of the oil pump rotates. This causes the gap between the gears to constantly narrow and open, sucking oil from the oil pan when the gap opens and pumping oil into the engine when it narrows.
At high engine speeds, the oil pump delivers much more oil than is needed to lubricate the engine. The oil pressure regulator prevents excess oil from entering the engine lubrication channels. With normal oil supply, the coil spring and valve hold the bypass closed, directing all of the oil to the engine. As the volume of oil pumped increases, the pressure rises to a level sufficient to overcome the spring force. This opens the oil pressure control valve, allowing oil to flow through the valve and drain back into the oil pan.
Oil pan
The oil pan is installed at the bottom under the cylinder block. The crankcase is located in the oil pan, the oil pan is made of aluminum alloy.
Engine oil is pumped from the oil pan by an oil pump. After passing through the oil filter, it is fed in two ways to lubricate the cylinder block and cylinder head. One way, the oil is pumped through oil passages in the crankshaft to the connecting rods and then to the pistons and cylinders. It then drains back into the oil pan. In the second path, the oil is pumped through the lubrication channels to the crankshaft. The oil passes through internal passages in the camshafts to lubricate the valve blocks before draining back into the oil pan.
An exhaust manifold
This engine uses a single four-hole header with rearward exhaust. The manifold is designed for direct exhaust from the combustion chamber with minimal back pressure. The oxygen sensor is mounted on the exhaust manifold.
Intake manifold
The intake manifold has four independent ports and uses a dynamic boost effect to increase torque at low to medium speeds.
Camshafts
DOHC engine (two overhead camshafts), which means there are two camshafts. One camshaft controls the intake valves, the other camshaft controls the exhaust valves. The camshafts are mounted on journals on top of the engine (in the cylinder head) and are held in place by the camshaft heads. Cylinder head camshaft journals are drilled to create oil passages. Pressurized engine oil enters the camshafts where it lubricates each camshaft journal. The oil returns to the oil pan through drain holes in the cylinder head. The camshaft lobes are integrated into a single camshaft to open and close the intake and exhaust valves to deliver the right amount of oil at the right time. The camshaft cams are flushed by pressurized oil injections from the camshaft journals.
Exhaust gas recirculation valve (EGR)
Exhaust gas recirculation system (EGR) used to reduce nitric oxide (NOX) in emitted harmful substances, formed due to the high combustion temperature. The main component of this system is the exhaust gas recirculation valve controlled by an electrical circuit.
The EGR valve supplies a small amount of exhaust gases to the intake manifold to lower the combustion temperature. The amount of recirculated gas is controlled by the ECM controller (ECM) in response to changes in engine load. When an excessive amount of exhaust gases enters, combustion does not occur. For this reason, very little exhaust gas is allowed to pass through this valve, especially at idle.
The EGR valve is usually open when:
- Engine warm-up
- Above idling speed