What are the dead and lowest dead points in the motor piston?

What are the dead and lowest dead points in the motor piston?

Did you get a motorcycle repair shop, then suddenly heard the mechanic say, “Try to find TMA first …” O “or piston already in TMB?” For some ordinary people, this term is foreign sound. There are those who think TMA and TMB are the secret mechanical codes, if it is actually the basis of motor engine work.

I’m myself first heard this term when my old supra motorbike suddenly bretbet and hard to live. The mechanic of the workshop said he had to put a valve, and explained that the position of the piston should be right in The long dead point Past. From there I was curious, what does it mean Topement point point This, and why is it important for a motorcycle machine?

Definition: What is the upper dead point (TMA) and the lowest dead point (TMB)?

Motorcycle machines, both 2-strokes and 4-strokes, work with principle upward and the piston movements in the cylinder. Well, there are two extreme positions achieved by the piston:

• Upper Dead Point (TMA): The position of the top piston of the cylinder.
• Low Dead Point (TMB): The lower piston position in the cylinder.

Why is it called “dead point”? Because when the piston reached this position, his actions stopped before turning. Although the machine rotates thousands of times every minute, this little time remains.

Without these two points, no such thing is like compressing, burning, or energy. So you can say, TMA and TMB is the heart of all machine tasks.

Important functionality of high dead point (TMA)

1. Maximum compression: Mixing air and fuel strongly depressed TMA, ready to be spark plug.
2. Ignition Benchmark: The time of ignition is often calculated from the Piston position of TMA. Little late, lost energy; Very easy, the machine can be dissolved.
3. Overlap the valve: In some cases the piston is in TMA, the reward of exhaust is not immediately closed while the entry route begins to open. It makes the gas redistribute more efficiently.
4. Machine settings: Mechanical use of TMA to set the valve, measure compression, to install the chain of time.

Important functionality of lower dead point (TMB)

1. Suck the mixture: When the piston descends TMB, the cylinder chamber is open open to mixing mixed air and fuel.
2. Discard the used gas: Piston also moves TMB in suffering step, helping to push the gas out.
3. Learn the engine stroke: The distance from TMA to TMB is called a stroke. This stroke determines machine capacity (CC).
4. Machine Character Impact: The machine with a long stroke (TMB in TMB plus) usually has a large low power. The short stroke is more appropriate for high rotation.

TMA-TMB paper in the 4-stroke engine cycle

Make it easy to imagine, try to see 4-stroke engine cycle:

1. Suction Step (TMA → TMB): The valve will enter the open, the piston drops, the air-rensin mixture to mix.
2. Compression Steps (TMB → TMA): Closed valve, the rise in the piston, mixed the mixture.
3. Business Steps (TMA → TMB): To the right of TMA, spark plugs, a mixture of burning, pushed by the piston. This is the main force.
4. Healing Steps (TMB → TMA): The reward is open, the piston will rise, the fuel goes out.

This cycle is back and forth thousands of times per minute, and the key is TMA and TMB.

The difference between TMA-TMB in 2-stroke vs 4-stroke engine

Many people are confused about the difference between a 2-stroke engine with 4-stroke context in the upper dead point.

• 4-stroke machine: Piston takes 2 times in crankshaft (4 steps) for 1 combustion. So TMA and TMB are also passed further “calm”.
• 2-stroke machine: The piston only takes 1 hour crankshaft (2 steps) for 1 combustion. That means TMA and TMB are often passed, the force to feel more “explosive”, but gas consumption is more wasteful.

Therefore, the RX King or other 2-stroke motorcycle is famous for fear: because every time the roller reached TMA, always burning.

Why is it important to understand TMA and TMB?

1. Maintenance Maintenance: Mechanics cannot set the valve or ignition without tofu tma.
2. Again: For those who want to have captives or withdrawal, TMA-TMB distance is the basis of the number of new machine capacity.
3. Problem Diagnosis: The negemption or non-powerful machine can cause compression leaks in TMA position.
4. Motorcycle Racing: The carbair team calculates the time of ignition, camshaft, and compression ratio with a reference to the TMA position.

Case Study: TMA disagreement can damage the engine

There’s a real story from my friend who likes the motorcycle OPREK. At that time he put a new valve on his duck motor, but forgot to make sure the piston was at the TMA position before setting up the timeline before being placed before placing. As a result, the valve and piston that prevents each other, the valve stretched, the machine could not survive. From there he knows, a small TMA error will make a big loss.

TMA-TMB visualization tips to make it easier to understand

If you have a problem imaginative, try to analyze the piston like a swing.

• When the swing arrives at the end of the end, that’s TMA.
• If the underground is reached, that’s TMB.
  That alternating movement continues to go to the machine.

Factors that influence TMA and TMB

1. Machine design (the x stroke is striking).
   
2. Piston head plange.
   
3. The weight of the valve and combustion.
   
4. Timing Camshaft Dan Crankshaft.
   

Only a small change can make character character different fromall.

TMB TMB of racing in the world: Time is all

In racing activity, understanding Topement point point Not just a theory. Mechanics of racing set:

• Ignition Timing: should take place before TMA to blast perfect.
• Valve timing is sold (Valve): Organized in such a way that the gas exchange around TMA is optimal.
• Stroke Length: Some career teams change the stroke to adjust the nature of power.

A little mistake, the motor can lose energy or even to blast the track.

What happens if the piston fails to reach TMA / TMB?

Damage to connecting the rod or crankshaft can be the piston no longer acts perfectly between TMA and TMB. The consequences:

• Leaky compression.
• The motorcycle is hard to live.
• Sound to the machine.
• Potential for Total Machine Chancent.

Finally

Now you understand, Topement point point Not just a technical term, but the core of the motor action.

• TMA is the position of the top piston, it is important for compression and ignition.
• dye is the lower position of the piston, is essential for suction and removal.

From two points, the power of the motorbike was born.

If you are a child garage, the TMA-TMB position is known. If you are an ordinary user, you know enough that healthy machine is determined by one of them from a smooth piston cycle between dead dead point.

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