How 4-Stroke Engine Works

Most of us have heard about a 2-stroke and a 4-stroke engine, but do we all know how really this engine works? Every vehicle needs an engine to provide the power for the said vehicle. The combustion that happens in our engine is responsible for the power we get from the vehicle that make it run. I will explain some of the details and information about a 4-stroke engine. First I will tell you the parts of an engine and then explain how these parts accordingly with the other parts.

Engine Cylinder

This the part where the combustion of the fuel and air mixture happens. This is a space where the piston travels. Commonly engine cylinders are typically cast from cast iron or aluminum before proceeding in a machine that polish the cylinder. Most cylinders now are made of Aluminum that really helps for faster and easier break-in. In the process of break-in of the engine, a simple irregularities in the break-in period may cause a ware in the cylinder sleeve. If later on it continues to wear the cylinder sleeve, you will come up reboring. Reboring is the process were you need to increase the diameter of the cylinder and piston rings.

Engine Valves

The one that control the timing and mixture of air and fuel that flow to the engine. The one also responsible for the outflow of burned gas after combustion. There are two type of valve, the intake valve and exhaust valve. The valve have components when installing in the engine, the stem oil seal, spring and the lock that holds the valve in its place.

Spark Plug

This is the one that transfer an electric current in the main chamber that ignite the fuel and air mixture.

Crankshaft

The part that converts reciprocating motion to rotation motion. This part is the one responsible for the push and pull movement of the piston connected by connecting rod.

Engine Piston and Piston Rings

A component for reciprocating engines or compressors. The piston is the part that moves to compressed the expanded fuel and air mixture inside the cylinder. Contains of piston rings usually compression rings and oil seal ring. These ring help the piston for covering and uncovering ports in the cylinder wall.

Connecting Rod

In an engine this part is the one that connects the piston to the crankshaft. With the help of the crank they form a simple mechanism that converts reciprocating motion to rotation. Its the one that push and pull the piston inside the cylinder.

These are the parts that is responsible in the combustion process inside the cylinder. Now I will explain how a 4-stroke engine works. There are 4 cycle in the process of combustion, the intake, compression, power and exhaust.

Intake

When the piston move downwards the intake valve is open and allows the flow of fuel and air mixture inside the cylinder. With the help of a cam lifter it will push the intake valve to open and keep the exhaust valve close.

Compression

In this cycle the piston moves upward compressing the mixture and the pressure produced by the compression shuts the intake valve. The piston move upward compressing the mixture and until before it reach the top part of the cylinder...

Power

At the end of the compression stroke before the piston reach its highest peak the spark plug  ignites producing electricity that burns the compressed fuel and air mixture. The force produced by burned gas pushes the piston downward.

Exhaust

When the piston reach the bottom, the exhaust valve and the piston upwards to push out the burned gas form from combustion. Then the cycle repeats and repeats.

How to Break-in your scooter

Break-in or breaking in or sometimes called mechanical running is the process of giving the scooter an initial running period with light load, normal load or heavy load. This is done to make sure that all wearing parts are fitted. This is to produce the last bit size adjustment that will give them stable relation to each other. The manufacturers give some specific driving guidelines written on the scooter manual on how to break in the scooter. The focus of engine break in is to make the piston, piston rings and cylinder wall be compatible to each other. Experts varies different suggestion on how to break in your engine, some says that it is good for a hard break in while other says it is much good with light break in. There is no set of instruction for breaking in an engine.The users manual recommends light break in at first because the scooter break in is already done in the factory. I hardly recommend a Hard Break in for your scooter for a smooth and powerful results. Just remember to vary your speed while breaking in and don't stick to your speed. And also changing the engine oil in the right time should be strictly done.

The goal of engine break in is for the piston, piston rings and cylinder wall. When the engine is powered up, the piston rings between the piston and cylinder will begin to seal and smoother. For a few years, the requirements for the break-in of engine has changed because of improved materials and design used in the engines now a day. Today Chrome Bore engine are use rather than Steel bore. It is much easier to break-in a Chrome Bore because of its smooth cylinder wall.

There are important preparations and planning which must be considered before running the engine. Break-in can take place from a running vehicle or while travelling but sometimes used the engine stand way of break in. Engine stand break-in is the process of breaking in the engine in center stand and not moving. Heating up only the engine in a period of time. Engine preparation varies also due to the factors that there are different types of engine and some conflict on expert suggestions. 

To prevent the increase of oil pressure in the engine, experts recommend to start with Revolution per minute or rpm and the run the engine for few  minutes. There are also some problems that can be encountered if your break-in is not good. Some cases of these are worn out cylinders because of improper break-in. The oil dried because of too much pressure in the engine and the owner forgets to check it. Letting the oil dry while breaking is really a bad idea that's why you should always check for the engine oil level. Sometimes other parts are also damaged when there is a failure in the engine, this consequence should be avoided because it will cost a lot replacing some damaged part.

Comparing the break-in process now from the past years you will notice that the required time significantly decreased from months to days to hours due to some reasons. One of the reason is the company upgrade facilities that is capable giving better output on engine parts and assembling. Some manufacturers also perform break-in in the factory before releasing the unit to the market. They also perform some test for the engine to ensure its performance, durability and endurance. Other reason is the growing knowledge and experiments on how they can make a more easier, faster and reliable manufacturing. Science had help manufacturers a lot when it comes for performance output and how they ca make the product more useful.