ASVAB Auto and Shop Information

ASVAB Auto and Shop Information Mixture of Gas and Air (the fuel mixture) - What does the Internal Combustion engine burn? 1. Intake 2. Compression 3. Power 4. Exhaust - What are the 4 strokes that make up a cycle? (in car engine) Intake - This valve opens as the connecting rod pulls the piston down, drawing the gas/air mix into the cylinder Compression - The valves are closed. The connecting rod pushes the piston up, compressing gas/air mix Power - The spar plug ignites the gas/air mix, forcing the piston down. That pushes down on the connecting rod, turning the crankshaft; the crankshaft turns the flywheel, which keeps the engine going Exhaust - The ___ valve opens as the connecting rod moves the piston back up, pushing out the exploded gases. The valves are times, of course, using pus rods attached to the camshaft. Inline - The name for cylinders that are arranged in one row V - The name for cylinders that are arranged in two rows Four-stroke, one-cycle engine - Most people refer to engines as four-cycle engines but this is false; what are they really called? Tachometer - Instrument in a vehicle the measures revolutions per minute; rpm (e.g. when this displays 4,800 rpm, that means the engine is performing 4,800 cycles every minute) Fuel must be properly mixed with air and transported within the cylinder at the proper time - What must happen in order for the cycle to happen at all? Carburetors - ___ are used (pre 1990) to mix the fuel and air mechanically. As air moves quickly through this, it creates a vacuum, which draws more and more fuel into the mixture Fuel Injectors - ___ have replaced carburetors on newer cars to perform the air/fuel mixture function. Fuel Injector - The ___ acts as the fuel-dispensing nozzle. It injects liquid fuel directly in to the engine's air stream. (In almost all cases it requires an external pump) Electronic Fuel Injection computer - EFI computer stands for ___? Determines the amount of fuel entering the engine: receives information from the sensors in the fuel, air, and exhaust system, and from that information, it determines how much fuel the engine needs to operate at optimum levels - What does the EFI computer do? Throttle - ___ is mechanically connected to the carburetor OR ___ is electronically connected to the EFI computer Advancing (opening) the throttle causes more fuel to be transferred to the carburetor or the fuel injectors. The accelerator (gas pedal) is connected to the throttle by mechanical linkages. The harder you push on the gas pedal, the farther the throttle is advanced (opened). Thus, more fuel is transported to the carburetor or fuel injectors. - What does a Throttle do? Cooling system - What does the engine have because of the high temperature at which fuel burns? Water Jackets Water Pump Radiator - What are the 3 components of the engine's cooling system? Water jackets - These surround the parts of the engine that reach the highest temperatures (engine cooling system) Water Pump - This circulates water through the water jackets (engine cooling system) Radiator - (engine cooling system) While the water circulates, it absorbs heat from the engine and then passes through the ___, where outside air cools the water. Antifreeze - ___ (a coolant) raises the boiling point of water (which keeps water from boiling away) and lowers its freezing point (which keeps the system from freezing up during cold weather) Antifreeze - ___ is usually mixed with the water in an engine cooling system Oil Pump - A ___ circulates oil through the engine; oil flows through the crankshaft and connecting rods, lubricating it as it goes.