Petrol models
The power system consists of a fuel tank installed in the rear of the car, an electric fuel pump placed in it, a fuel filter, injection injectors, a fuel pressure regulator, an air cleaner assembly, a throttle body, and also laid under the bottom of the car and connecting the fuel tank to the fuel line of the supply lines and fuel return. All models are equipped with an electronic fuel injection system controlled by the ECM (see part Fuel injection system for gasoline engines).
Accumulating in the tank and fuel lines while the car is parked, fuel vapors are accumulated in an adsorber filled with activated carbon, from where they are then discharged into the intake tract and burned during the normal operation of the engine.
Information about fuel consumption is displayed on the dashboard of the car.
Driving style has a significant impact on fuel consumption. Here are some tips for judicious use of the accelerator pedal on vehicles equipped with a fuel injection system:
- In any weather (even in the cold) start driving immediately after starting the engine;
- When stopping the car for more than 40 seconds, turn off the engine;
- Try to always move in the highest possible gear;
- On long journeys, try to maintain a constant speed. Avoid driving at excessively high speeds. Drive your car carefully, avoid unreasonable braking;
- Do not transport excess cargo in the car, if not necessary, remove the top rack from the roof;
- Check tire inflation pressure regularly - try not to let it drop too low.
Diesel models
The fuel system consists of a fuel tank installed at the rear of the vehicle, equipped with a built-in moisture separator, a heated fuel filter, a high pressure fuel pump (injection pump), injectors and connecting components of the fuel line system
The injection pump draws fuel from the tank and forces it through the fuel filter, where foreign particles and moisture are trapped. Excess fuel not consumed by the engine is used to lubricate the internal components of the pump, after which it is returned to the fuel tank.
The injection pump is driven by the crankshaft. The operating speed of the pump is exactly half the speed of the crankshaft. The high pressure required to open the injectors and inject fuel into the prechambers/directly into the cylinders is provided by the use of a radial plunger pump.
The high-pressure fuel pump is electronically controlled, thanks to which the engine fully meets the ever-tightening international requirements for reducing exhaust toxicity. The main elements of the control system are the electronic engine control module (ECM), a high pressure fuel pump control unit and a set of information sensors built into the pump assembly (see part Diesel fuel injection system).
Four fuel injectors inject atomized fuel into the prechambers of the cylinders. Optimization of the combustion process of the mixture is ensured by fine calibration of the injectors. The nozzle needles are lubricated by the fuel accumulated in the spring chambers, the unclaimed excess fuel is returned to the injection pump via separate lines.
In order to increase the efficiency of the return, the X15DT engine is equipped with a turbocharger that provides excess pressure in the intake piping relative to atmospheric pressure, which makes it possible to increase the mass flow rate of the air supplied to the cylinders - the fuel supply also increases proportionally. Installed between the exhaust manifold and the downpipe of the exhaust system, the turbocharger, powered by exhaust gas pressure, draws air from the air cleaner and, if equipped, drives it through the intercooler heat exchanger mounted on the left side of the radiator of the cooling system (intercooler) and pressurized into the intake manifold. The task of the intercooler is to cool the air supplied to the engine, which is heated during compression in the supercharger. Since the cooled air has a higher density, lowering its temperature allows you to further increase the efficiency of the engine output.
An excessive increase in pressure in the intake manifold is prevented by the use of a special safety valve that ensures the removal of exhaust gases from the turbocharger using a pressure-sensitive actuator. The valve actuation occurs at the command of the ECM. The sensor-switch, sensitive to pressure change, provides operation of the control lamp built in a dashboard warning the driver about excess of admissible boost pressure.
The turbocharger is lubricated by engine oil coming through a special tube from the cylinder block - the turbine shaft is literally «floats» in oil, - from the supercharger, the return line oil flows back into the oil pan. The turbocharger is equipped with an integrated pressure relief valve and a vacuum diaphragm to regulate the boost pressure in the intake manifold. The internal components of a turbocharger rotate at high speed and are very sensitive to oil quality. The impact of foreign particles on the rotating blades of the turbine can have the most serious consequences. In view of the above, before removing the compressor, it is necessary to thoroughly clean its outer surfaces, as well as the surfaces of the components located in the neighborhood. Place the removed components in a tightly closed container. Seal all openings in the compressor immediately with adhesive tape, use only lint-free rags to wipe the parts.
In no case do not start a turbocharged engine with the intake duct removed - the depth of vacuum at the compressor inlet can increase abruptly, which increases the risk of foreign objects being sucked into the turbine and then thrown out at high speed!
The fuel system of diesel engines is extremely reliable. Provided that clean fuel is used and maintenance procedures are performed regularly, it should function properly until the end of the vehicle's life. With high mileage, the internal components of the injection pump and injectors may wear out and require refurbishment. - Due to the complexity of the design of the components, repairs should be entrusted to car service specialists.
Safety precautions and cleanliness when working with the fuel system
General rules
Do not approach the work area with an open flame or a lit cigarette. Always keep a fire extinguisher ready.
Fuel fumes are poisonous - make sure that the workplace is well ventilated.
The fuel system is under pressure. When opening the system, fuel can escape from it under pressure - before releasing the fitting connectors, wrap them with rags. Wear protective goggles.
Take special precautions when working on diesel engine power system components. In particular, this statement applies to injector maintenance procedures. Remember that the fuel pressure at the outlet of the injectors is about 1100 atmospheres - do not put your hands and other body parts under the jet.
To fasten hose connections, band and clamp type clamps are used. After disconnecting the hoses, the clamping clamps should be replaced with band or worm clamps. Fixing the locks of some clamps requires the use of special tools - consult with Opel branded service specialists.
Before disconnecting the in-line connectors, thoroughly wipe them from the outside to prevent dirt from getting inside the tract.
Place the removed components on a clean lining and wrap in polyethylene or paper - avoid using lint-free rags for wiping and wrapping the components.
If repairs take time, make sure that all open holes in the nodes and components of the power system are carefully plugged.
Replace only clean parts. Remove spare parts from the packaging only immediately before installation. Do not use parts that have been stored unpackaged (e.g. toolbox).
Avoid using compressed air with an open fuel path. If possible, try not to move the car.
Do not use sealants containing silicone. Silicone particles that get into the engine do not burn out and can cause damage to the lambda probe.
Safety precautions when removing the fuel tank
Before removing the tank, drain the fuel from it or pump it out with a pump specially designed for this purpose.
The fuel tank is removed from the underside of the vehicle. Before releasing the mounting tapes, support the tank from below with a trolley jack - lay a wooden block between the tank and the head of the jack.
An empty tank is explosive and must be cut into pieces before disposal - try not to allow sparks when cutting the tank. It would be best to hand over the tank to a special collection point.
After installing the tank, start the engine and check the tightness of all connections.
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