Four-Stroke Cycle
In order to convert gas into motion, an engine operates in a four-stroke cycle. Also known as the Otto cycle, almost all cars currently operate in this manner.
01
Intake
With stroke one, the piston is in the top position, the intake valve opens and the piston moves to down to enable the engine to take in a cylinder-full of air and gasoline. Only the tiniest drop of gasoline needs to be mixed into the air for this to work.
02
Compression
With stroke two, the piston moves back up to compress the gasoline/air mixture.
03
Combustion
With stroke three, the spark plug provides a spark to ignite the gasoline. The charge in the cylinder explodes, driving the piston back down again. This is also known as the power stroke, which is the main source of the engine's torque and power.
04
Exhaust
With stroke four, the piston hits the bottom of its stroke, the exhaust valve opens and the exhaust gas is pushed out of the cylinder as the piston moves back up. The exhaust gas passes through the catalytic converter, exiting the vehicle through the tailpipe. With the completion of the cycle, the engine is ready to start the process all over again. In a car moving at 60 mph, it does this about 600 times per minute.
- A clean engine burns fuel more efficiently. And BP gasoline with Invigorate cleans critical engine parts. With continuous use, it can even restore some of the fuel economy your dirty engine parts were stealing.
- Gas mileage usually decreases at speeds over 60 mph. So observing the speed limit can save on gas—and speeding tickets. Use your cruise control on long trips to keep your speed in check.*
- Inflate your tires to the correct psi. Not only will properly inflated tires improve your gas mileage, but they'll also last longer and give you a safer drive.*
