Design features of the Opel Astra H engine

For the Russian market, Opel Astra cars are equipped with the following engines: 1.4 liter Z 14 XER (90 hp); 1.6 L Z 16 XER (115 hp); 1.8 L Z 18 XER (140 hp); 2.0 L Z 20 LER (200 HP) and 2.0 L Z 20 LEH (240 HP). The Z 14 XER engine equipped with the Twinport system is installed only on the five-door hatchback, while the Z 16 XER and Z 18 XER engines with variable valve timing are installed on all cars, except for the sports trim levels of the three-door hatchback. The Z 20 LER and Z 20 LEH turbocharged engines are only fitted to the three-door hatchback in sport trims.

This section describes the design and repair of some components and systems of the engine mod. Z 16 XER (105 hp). Engine repair mod. Z 16 XER, as well as some aspects of maintenance and repair of engines mod. Z 18 XER, Z 14 XEP, Z 20 LER and Z 20 LEH are given in a separate section (see section "Design and repair features of engines").

The cylinder head of the engine is made of aluminum alloy according to the transverse cylinder scavenging pattern (inlet and outlet channels are located on opposite sides of the head), seats and valve guides are pressed into the head. The intake and exhaust valves are equipped with one spring each, fixed through the plate with two crackers.

The engine cylinder block is a single casting that forms the cylinders, the cooling jacket, the upper part of the crankcase and five crankshaft bearings made in the form of crankcase partitions. The block is made of special ductile iron with cylinders bored directly in the body of the block. Engine main bearing caps are machined complete with blocks and are therefore not interchangeable. On the cylinder block, special lugs, flanges and holes for fastening parts, assemblies and assemblies, as well as channels of the main oil line are made.

Camshafts are cast, cast iron. The intake and exhaust camshafts are equipped with timing rotors that provide the operation of the camshaft position sensors. Oil channels are made in the intake and exhaust valve drive shafts, through which oil is supplied under pressure to the mechanisms of the variable valve timing system.

The crankshaft , forged from special steel, rotates in main bearings with thin-walled steel liners with an anti-friction layer of aluminum-tin alloy. The axial movement of the crankshaft is limited by special flanges made on the middle main journal and resting on the shoulders of the thickened middle main bearing shells.

The pistons are made of aluminum alloy.

On the cylindrical surface of the piston head there are annular grooves for oil scraper and compression rings. The engine pistons are additionally cooled by oil supplied through a hole in the upper head of the connecting rod and sprayed onto the piston bottom.

The piston pins are installed in the piston bosses with a gap and are pressed with an interference fit into the upper heads of the connecting rods, which are connected with their lower heads to the connecting rod journals of the crankshaft through thin-walled liners, the design of which is similar to that of the main ones.

Connecting rods are steel, forged, with an I-section rod.

Combined lubrication system .

The closed-type crankcase ventilation system does not communicate directly with the atmosphere, therefore, simultaneously with the exhaustion of gases and gasoline vapors, a vacuum is formed in the crankcase under all engine operating modes, which increases the reliability of various engine seals and reduces the emission of toxic substances into the atmosphere.

The engine cooling system is sealed, with an expansion tank, consists of a cooling jacket made in casting and surrounding the cylinders in the block, combustion chambers and gas channels in the cylinder head. Forced circulation of the coolant is provided by a centrifugal water pump driven by a crankshaft timing belt. To maintain the normal operating temperature of the coolant, a thermostat is installed in the cooling system, which closes a large circle of the system when the engine is cold and the coolant temperature is low.

The engine power system consists of an electric fuel pump installed in the fuel tank, a throttle assembly, a fine fuel filter, a fuel pressure regulator, injectors and fuel lines, and also includes an air filter.

The variable valve timing system dynamically adjusts the position of the intake and exhaust camshafts. This system allows you to set the optimal valve timing for each moment of engine operation, resulting in increased power, better fuel economy and less exhaust emissions. The mechanism of the system is connected by channels in the cylinder head and in the camshafts with solenoid valves. These valves hydraulically control the variable valve timing mechanism. The solenoid valves, in turn, are controlled by the electronic engine control unit.

The solenoid valve, consisting of an electromagnet and a valve (which, in turn, consists of a spool and a spring), at the signals of the electronic engine control unit, supplies oil under pressure from the main line of the lubrication system to one of the working cavities of the variable valve timing system mechanism and drains the oil from another cavity, which leads to the mutual movement of the elements of the mechanism and, as a result, to a dynamic change in the position of the intake and exhaust camshafts.

While the engine is idling, the electronic engine control unit repeatedly activates the solenoid valve for short periods of time in order to clean its elements and channels from contaminants that accidentally get into them.

When the power is turned off to the electromagnetic valves of the variable valve timing system, the oil supply holes from the main line and drain are fully open and the mechanism is set to its original position. In this case, the engine runs without changing the valve timing.