An Automobiles fuel systemWritten by Kevin Schappell
The fuel system feed your engine gasoline/diesel it needs to run. If anyone of parts in system break down your engine will not run. Let's look at major parts of fuel system, Fuel tank: Basically a holding tank for your fuel. When you fill up at a gas station gas travels down filler tube and into tank. In tank there is a sending unit, which tells gas gauge how much gas is in tank. Fuel pump: On newer cars fuel pump is usually installed in fuel tank. Older cars have fuel pump attached to engine or on frame rail between tank and engine. If pump is in tank or on frame rail then it is electric and is run by your cars battery. Fuel pumps mounted to engine use motion of engine to pump fuel Fuel filter: Clean fuel is critical to engine life and performance. Fuel injectors have tiny openings, which clog easily so filtering fuel is only way to prevent this. Filters can be before or after fuel pump, sometimes both. Fuel injectors: Most domestic cars after 1986 and earlier foreign cars came from factory with fuel injection. Instead of a carburetor to mix fuel and air, a computer controls when fuel injectors open to let fuel into engine. This has resulted in lower emissions and better fuel economy. The fuel injector is basically a tiny electric valve, which opens and closes with an electric signal. In picture below you can see injectors towards outer part of intake. By injecting fuel close to cylinder head fuel stays atomized ( in tiny particles ) so it will burn better when ignited by spark plug. Carburetors: A carburetor takes fuel and mixes it with air without computer intervention. While simple in operation, they tend to need frequent tuning and rebuilding. This is why most newer cars have done away with carburetors in favor of fuel injection. Common Problems: I would say most common problem is a clogged fuel filter. Make sure you follow your manufacturers recommendations as to when you should change fuel filter. This information should be in your owner’s manual. Symptoms include sputtering at high speeds or engine not starting at all. Always check ignition system first, if that's ok then next suspect is fuel filter. Next most common problem is fuel pump failing. Most modern electric fuel pumps can be heard when you turn key on. If you don't hear pump running and your car will not start, it could be your fuel pump. The first thing a mechanic will check is relay, which sends power to pump. If this is operating correctly then pump will have to be replaced.
| | The Cooling SystemWritten by Kevin Schappell
The purpose of engine's cooling system is to remove excess heat from engine, to keep engine operating at its most efficient temperature, and to get engine up to correct temperature as soon as possible after starting. Ideally, cooling system keeps engine running at its most efficient temperature no matter what operating conditions are. As fuel is burned in engine, about one-third of energy in fuel is converted into power. Another third goes out exhaust pipe unused, and remaining third becomes heat energy. A cooling system of some kind is necessary in any internal combustion engine. If no cooling system were provided, parts would melt from heat of burning fuel, and pistons would expand so much they could not move in cylinders (called "seize"). The cooling system of a water-cooled engine consists of: engine's water jacket, a thermostat, a water pump, a radiator and radiator cap, a cooling fan (electric or belt-driven), hoses, heater core, and usually an expansion (overflow) tank. Fuel burning engines produce enormous amounts of heat; temperatures can reach up to 4,000 degrees F when air-fuel mixture burns. However, normal operating temperature is about 2,000 degrees F. The cooling system removes about one-third of heat produced in combustion chamber. The exhaust system takes away much of heat, but parts of engine, such as cylinder walls, pistons, and cylinder head, absorb large amounts of heat. If a part of engine gets too hot, oil film fails to protect it. This lack of lubrication can ruin engine. On other hand, if an engine runs at too low a temperature, it is inefficient, oil gets dirty (adding wear and subtracting horsepower), deposits form, and fuel mileage is poor-- not to mention exhaust emissions! For these reasons, cooling system is designed to stay out of action until engine is warmed up. There are two types of cooling systems; liquid cooling and air cooling. Most auto engines are cooled by liquid type; air cooling is used more frequently for airplanes, motorcycles and lawnmowers. Liquid cooled engines have passages for liquid, or coolant, through cylinder block and head. The coolant has to have indirect contact with such engine parts as combustion chamber, cylinder walls, and valve seats and guides. Running through passages in engine heats coolant (it absorbs heat from engine parts), and going through radiator cools it. After getting "cool" again in radiator, coolant comes back through engine. This business continues as long as engine is running, with coolant absorbing and removing engine's heat, and radiator cooling coolant. A cooling system pressure tester is used to check pressure in cooling system, which allows mechanic to determine if system has any slow leaks. The leak can then be found and fixed before it causes a major problem.
|
