What makes the engine tick
Components of the engine
Did you ever wonder how the engine works? Let me explain it to you.
The components of the engine consist of:
- Valves and rockers
- Connecting rods
- Combustion chamber
- Timing belt
Most gasoline-powered engines operate in the sequence of:
Intake, Compression, Power, Exhaust. Hence the name four stroke.
The intake VALVES are devices that allow a fuel/air mixture to enter the COMBUSTION CHAMBER at a very specific time and duration. The exhaust valves open during the exhaust stroke to allow the spent gases to exit the engine. Every car employs a system of opening and closing the valves. Most Hondas use CAMSHAFTS and adjustable ROCKERS to operate the valves. Some use hydraulic rockers to operate the valves. The difference is that hydraulic rockers are virtually maintenance free, whereas solid rockers need periodic adjustment.
The camshaft is a thick bar with lobes on which the rockers ride. They are designed to open and close the valves to optimize the intake and exhaust processes to maximize power and efficiency. Some engines employ numerous camshafts to allow the engine to accommodate more valves per cylinder. More valves per cylinder usually means more power output with better efficiency.
The PISTONS are circular devices with a relatively flat top that move up and down inside the CYLINDERS to compress the mixture of fuel/air after it enters the combustion chamber and force out the spent gases after combustion has taken place. The volume of area when the piston is at the very top of its stroke multiplied by the number of cylinders determines the size of that particular engine. The explosion of gases during the compression stroke forces the pistons down. This process is repeated sequentially for each cylinder according to when its piston reaches the top of its compression stroke.
The TIMING BELT is a fiberglass and rubber belt driven by the CRANKSHAFT turning the camshaft at exactly one half crankshaft speed. The timing of the connection is crucial to the smooth running of the engine. The timing belt requires periodic replacement and regular adjustment. The crankshaft is a heavy rotating shaft that connects the pistons through the CONNECTING RODS. The crankshaft drives the transmission producing power to drive the car. The weight of the crankshaft is usually exactly the same as the connecting rods and pistons. Newer Hondas have larger pistons. To make the engine as smooth as a 6 or 8 cylinder engine, the Honda engine employs two rotating balance shafts inside the engine. These balance shafts counteract the weight of the larger pistons, giving a very smooth idle. The crankshaft is driven by the force of the explosions of the mixture during the compression stroke. The compression stroke of each cylinder in turn creates a smooth running engine at all Rpm’s. The more cylinders an engine has, the smoother the engine runs and the more power it produces.
When you turn the ignition switch to the start position, several things happen at the same time. The starter turns the crankshaft at about 100 RPM. This allows the piston to compress the air/fuel mixture in the cylinder enough to create more pressure from the explosion when the spark plug fires, forcing the piston down, turning the crankshaft. The engine starts and the idle stabilizes. As you step on the throttle pedal, the RPM rises, more fuel/air mixture is injected into the cylinder, causing the engine to rev faster.
The carburetor or fuel injection system controls the amount of fuel/air mixture that is drawn into the engine by the pressure on the throttle pedal. In a fuel-injected engine, only the amount of fuel/air mixture that the engine can use at that particular moment is drawn into the combustion chamber no matter how far the throttle pedal is depressed. The fuel injection system also limits the RPM that the engine can rev to by cutting off the supply of fuel to the injectors. Usually this limit is the redline of the engine. When the ignition is switched off, the fuel is cut off killing the engine.
The newest engine from Honda is the i-VTEC I Direct injection engine. For a small engine (2.0L) it is capable of high mileage, more torque, and more horstpower while running cleaner than any previous engine. This short video explains the working of this new engine: