KNOW WHY THERE IS BULGE IN EXHAUST PIPE OF DIRT BIKE !

Dirt bike engine uses two stroke gasoline engine.The exhaust pipes of dirt bikes are shaped strange. They expand into a wide diameter and then shrink down to a very small diameter where the exhaust gasses emerge into the environment.In this article we will understand why these exhaust pipes are shaped in that manner.

That bulge is called an expansion chamber, and it is used to increase the horsepower of the engine . This technique only works on two-stroke engines, which is why you see it on a lot of dirt bikes but not on street bikes. Most street bikes use four-stroke engines.

The basic idea behind an expansion chamber is to use the momentum and pressure of the exhaust gases to create a pump that squeezes more air and fuel into the cylinder during the intake stroke. It does the same sort of thing that a turbocharger does, but it does it without moving parts.

How it works:

While moving downwards after ignition, the piston exposes the exhaust opening, and the burned gas streams into the exhaust pipe like a (high pressure) shock wave.

Due to the inertia, this gas will create a slight vacuum wave behind it, which helps to suck out more burned gas, but also fresh gas as soon as the intake opening is uncovered. 

The first cone helps to increase the vacuum: When the gas travels through the pipe with a certain speed, it travels through a certain volume per time. If the cross section is increased and the speed remains the same, the wave travels through a larger volume. This creates more vacuum volume behind the wave.

Now we have fresh gas in the cylinder, but also in the manifold. The shock wave now hits the right cone and gets reflected.That is, you now have a shock wave running towards the cylinder. It hits the fresh gas right in the moment when the intake opening is covered by the piston, and presses this gas into the cylinder. When the piston covers the exhaust opening, too, the fresh gas already is under some pressure.

This way, the exhaust forms some kind of compressor, increasing the volumetric efficiency / power of the motor.

KNOW WHY MANHOLES ARE ROUND IN SHAPE !!

You might have noticed that most manholes, and their covers, are round in shape.We will discuss the reason behind the round shape of manhole cover in this article.

1.Mishandling the Manhole cover-A round manhole cover cannot fall through its circular opening, whereas a square manhole cover could fall in if it were inserted diagonally in the hole.

2. Rolling the Manhole Cover -A round manhole cover is easily moved and rolled.

3. Strongest shape-When a square or rectangular manhole cover is subjected to sudden vertical compression (think of a very heavy truck driving over it), the weakest spot, the center, isn't equidistant to all supporting sides, especially the corners, which give support from two directions and are thus the strongest points (for similar reasons, experts recommend you stand in the corner of a room during an earthquake). With a circular cover, the center is equidistant from all supporting sides, and due to the gradual curve, any point along the edge gives almost as much support as a corner on a square cover. Circular shape results in uniform stress distribution.

4. Circular covers don’t need to be rotated or precisely aligned when placing them on the opening.

5. Round tubes are the strongest shape against the compression of the earth around them, so the cover of the tube would naturally be round as well.

6. It’s easier to dig a circular hole.

KNOW WHY HEADLIGHTS OF NEW MOTORBIKES ARE ALWAYS ON !!

You might have seen all two-wheelers which are launched after 2017 have their headlights always ON, we do not have an option to turn it OFF. In this article, we will discuss the reason behind always ON headlight in two-wheelers.

All new motorcycles and scooters that roll into the market need to feature AHO from April 1st, 2017 onwards. Most two-wheeler manufacturers term AHO as All-time Headlight On or Automatic Headlight On system. As the name suggests, new motorcycles and scooters which are sold and registered after April 1st, 2017 need to have the headlights on at all times. Yes, even during the day.

This is in compliance to a notice issued by the Road and Transport Ministry of India. All new bikes equipped AHO will not have a button to switch on the headlight, since it will always be on, but will only get high-beam and low-beam buttons along with the pass switch.

Why headlights need to be turned ON always:

This is a safety measure initiated by the ministry and is followed in many international countries. The idea behind this is that keeping headlights on throughout the day, even when the sun is nice and bright, makes spotting two-wheelers easier on the road. So, others on the road can see the motorcycle or scooter from a distance. It is also helpful during tricky light conditions during dusk, dawn or in case of sudden clouds casting a shadow. In short, it is a safety measure to increase the visibility of the two-wheelers on the road so that accidents can be prevented.


This will strain two-wheeler batteries a little more, but without hampering the battery in any way. Most modern motorcycles and scooters use advanced battery and alternators system, which can comfortably manage the extra load. This will no way alter fuel economy either. So, no need to worry.

Now-a-days most of the companies are coming up with DRL (Day-time Running Lights) on their motorcycle headlights as seen on the Bajaj Platina. This is basically a small, but fairly bright strip of light incorporated in the headlight console. This strip remains illuminated even if the headlight isn’t switched on, so that the on-coming traffic can clearly see the motorcycle or scooter approaching.

KNOW WHY WASHER IS USED WITH NUT AND BLOT !!

Washers are often used in conjunction with threaded fasteners. Washers consist of a flattened, circular- or disc-shaped piece of metal with a hole in the middle. Skipping on washers can dramatically reduce the lifespan of how your product is put together. Ultimately, that leads to disaster for the product itself. Not just any washer will do for all applications. Once you understand that, you can give washers the respect they deserve. In this article, we will discuss the use of washers with respect to nut and bolts.

Load Distribution

The primary purpose of most washers is to evenly distribute the load of the threaded fastener with which they are used. Threaded fasteners stress the material in which they are driven. For example, driving a screw into the wood may cause the wood to crack around the surface. Washers reduce the risk of such damage by evenly distributing the fastener’s load across the surface of the material. Not all materials require the use of washers. 

But for wood and other relatively soft materials, washers are useful to protect against stress-related damage when the threaded fastener is driven into the material.

Spacing

Washers can also be used as spacers. If the threaded fastener is longer than the depth of the object, you won’t be able to drive it all the way into the object — not without having some of the fastener stick out the back of the object, at least. Driving a 4-inch screw into an object that’s 3 inches deep will result in 1 inch of the screw’s tip protruding out of the back of the object. 

A simple solution to this problem is to use washers. Placing washers through the threaded fastener before driving it into the object creates padding so that the fastener doesn’t go too deep.

Vibration Absorption

Certain types of washers are designed to absorb vibrations. Known as vibration damping or vibration-isolating washers, they usually aren’t made of metal. Instead, they are made of a softer material like plastic, rubber or urethane. Softer materials such as these are more effective at absorbing vibrations than hard materials, including metal.

If a threaded fastener is being used to connect two objects, and one of those objects producing vibrates aggressively, using vibration-damping washers can protect the other object from damage.

Liquid Protection

Other types of washers prevent the ingress of water and liquids. They are often used in water pipes and connections to create a waterproof seal. Like vibration-damping washers, liquid-sealing washers are made of a soft material that’s able to press completely against the surface of the object.

KNOW THE MECHANISM BEHIND EMERGENCY PULL CHAIN !!

You might have seen an Emergency pull chain in Railways. The chain is used to stop the train at the time of an Emergency. Most of us though know what the Pull chain is been used for but do not know the exact mechanism of it. Here is a brief description of what exactly happens in a Train when you pull the Emergency chain.

In a Typical Indian train, the coaches are interconnected by two pipe hoses. The alarm pull chain is in continuity with the Brake pipe (As in the Schematic diagram below) constantly maintained at specific air pressure.
Whenever the chain is been pulled some Air (earlier vacuum drop was used) escapes from the Passenger Emergency Alarm Valve ( PEAV ) vent. 
 

This drop in pressure results in the application of the brake cylinder/piston assembly in the bogie of the coach, which starts pressing the brake pads on the wheels or disc of the entire train. The loco pilot also notices the air pressure drop in the gauge and then uses his own skills to help the train stop comfortably.

As soon as there is pressure drop, the driver whistles in "two short one long" to indicate to the guard and the train TTEs that there has been Alarm chain pulling.

The guard's compartment also has the air pressure gauge which gives him an indication.

Also recently the coaches have been fitted with emergency flashers on the sidewalls of the coaches, and these flashers are also activated when the brake pipe pressure is lost for any reason other than the driver's application of the brakes.

Assistant Driver and Guard find out in which coach the ACP actually occurred and help to "put right" the concerned coach i.e. the lever needs to be manually reset that helps to release the brakes of that coach. Until this is done, the lamp and buzzer in the locomotive cab are continuously activated. The air pressure system again builds up air pressure and that releases all brakes of all coach and the train gets ready to depart.

KNOW WHY BUCKETS GENERALLY HAVE FRUSTUM SHAPE !!

You might have noticed that buckets generally have a conical or frustum like shape. Have you ever wondered why is it designed so? Why not any other shape?
We will discuss the reason behind the conical shape of the bucket in this article.

The bucket is designed in conical shape due to the following reasons:

1.)A bucket is typically used to put something in, e.g. you dip a mug in it or wash something in it. This means having a large top area is useful for easy access.

2.)It makes it easy to hold or lift the bucket of such shape as any other shape like a cylinder or frustum upside down will have the chances of slipping down.

3.)The center of gravity of frustum shape is such that it provides the least effort and easy means to lift it.

4.)While pouring down the water or liquid out, the frustum of the cone-shaped bucket provides easy grabbing and balance and comfort.

5.)This shape allows multiple buckets to be stacked (nested) inside each other, providing both dense and secure storage of large numbers of buckets.

Compared to the cylinder, a frustum shape gives maximum weight distribution while lifting thus minimum effort is used while lifting bucket of frustum shape.

KNOW WHY 10:10 IS DEFAULT TIME IN CLOCK !

You might have noticed that the watches and clocks found in product photographs and advertisements usually show the time 10:10.Have you wondered the reason behind this.We will discuss the reason for this in this article.

 

These are some reasons why exactly this time is chosen.According to the New York Times, the main reason is quite simple and obvious: aesthetics. There are a number of visual advantages to having the hands set at the 10:10 positions.

1.)One is that the hands are kept from overlapping at this position. Having them on both sides of the watch face ensures that the hands themselves are visible and can be appreciated.

2.)When we look at a watch at 10:10, we consider as if the watch is smiling. It is lovely to have a smiling face, rather than having a crying face when the time is at 8:20. So the form of the hands has a positive effect on the view.

 3.)The arrangement of the hands is symmetrical, which people generally find more pleasant than asymmetry, making the product more appealing to customers.

4.) The manufacturer's logo, usually is in the center of the face under the 12, is not only visible but nicely framed when the needles are positioned at 10:10.

5.) Additional elements on the face (like date windows or secondary dials), usually placed near the 3, 6, or 9, won't be obscured.

There are a number of urban legends regarding the 10:10 time floating around in the world. Many of them attribute it to a historic event (e.g. Lincoln/JFK assassinations, the dropping of the atomic bombs), but there isn’t any truth behind those explanations.