New 5-Stroke Engine to Boost Efficiency and Reduce Emissions

Our four stroke engines have been around for a very long time and while many small changes have been made to them over those many years, the basic principal of operation has remained the same. Now, a new engine design that uses an additional stroke

Ilmor Engineering is the firm behind the new design and is currently able to get 130 horsepower 

 Considering the total displacement is 700cc, those numbers are fairly impressive. By using a turbocharger and keeping rotating mass at a minimum, the new engine is said to already be at least 5% more efficient that it's four stroke counterparts.

working:

This  design uses 3 different cylinders to produce power, but only two of these actually fire. The outside cylinders go through the normal procedure of intake, compression, combustion and exhaust to make their power. The cylinder located in the center however, receives the exhaust gas from one of the outside cylinders and allows it to expand even more, creating power.

The outside cylinders alternate to keep pressure even across the board. The result of this additional step is a torque curve similar to a diesel while still being able to ignite from a spark plug and without the emissions associated with diesel fuel.

advantages:

1. Fuel consumption is decreased by 10% over conventional 4 stroke operation
2. less weight
3. better mileage

conclusion:

Even without the reduction in size, Ilmor engineers are estimating a final output of around 150 horsepower but the time they are finished tweaking. Considering most engines of the same output are nearly 3 times as large as the new five stroke, it's safe to say this could change the future of automobiles.

for video :

www.youtube.com/watch?v=-yo6xuVS7tg

Connecting rod

The connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion.

As a connecting rod is rigid, it may transmit either a push or a pull and so the rod may rotate the crank through both halves of a revolution, i.e. piston pushing and piston pulling. Earlier mechanisms, such as chains, could only pull. In a few two-stroke engines, the connecting rod is only required to push.

In modern automotive internal combustion engines, the connecting rods are most usually made of steel for production engines, but can be made of T6-2024 and T651-7075 aluminum alloys (for lightness and the ability to absorb high impact at the expense of durability) or titanium (for a combination of lightness with strength, at higher cost) for high performance engines, or of cast iron for applications such as motor scooters. They are not rigidly fixed at either end, so that the angle between the connecting rod and the piston can change as the rod moves up and down and rotates around the crankshaft. Connecting rods, especially in racing engines, may be called "billet" rods, if they are machined out of a solid billet of metal, rather than being cast.

The small end attaches to the piston pin, gudgeon pin or wrist pin, which is currently most often press fit into the connecting rod but can swivel in the piston, a "floating wrist pin" design.

 The big end connects to the bearing journal on the crank throw, in most engines running on replaceable bearingshells accessible via the connecting rod bolts which hold the bearing "cap" onto the big end.

 Typically there is a pinhole bored through the bearing and the big end of the connecting rod so that pressurized lubricating motor oil squirts out onto the thrust side of the cylinder wall to lubricate the travel of the pistons and piston rings. Most small two-stroke engines and some single cylinder four-stroke engines avoid the need for a pumped lubrication system by using a rolling-element bearing instead, however this requires the crankshaft to be pressed apart and then back together in order to replace a connecting rod.

for best video see it: 

www.youtube.com/watch?v=hp931tDlHoU

cam shafts

                                                                  cam shafts

The crankshaft, sometimes abbreviated to crank, is the part of an engine that translates reciprocating linear piston motion into rotation. To convert the reciprocating motion into rotation, the crankshaft has "crank throws" or "crankpins", additional bearing surfaces whose axis is offset from that of the crank, to which the "big ends" of the connecting rods from each cylinder attach.
It typically connects to a flywheel to reduce the pulsation characteristic of the four-stroke cycle, and sometimes a torsional or vibrational damper at the opposite end, to reduce the torsional vibrations often caused along the length of the crankshaft by the cylinders farthest from the output end acting on the torsional elasticity of the metal.

Types of crank shaft:
                                                   1. Casting

                                                    2. Forging

                                                    3. Billet machined

Cast Cranks:
These are around for a long time and are found In a lot of engines and in both petrol and diesels.
As the name suggests these are cast and made from Malleable Iron. The shape being defined by a sand mould as with many other engine parts.
These are pretty cheap to make and hold up fairly well too so they are a common choice for manufacturers.
A sand mould is made comprising of a top and bottom half, a pattern is made in wood or other material and this forms the required shape the mould halves contain once they are brought together. The molten metal flows into this mould relying on gravity alone.

Both flat plane (single plane) and cross plane cranks can be made this way fairly easily.
A flat plane crank is one where the journals are 180 degrees apart common in all in-line four engines.
Therefore only two mould halves are needed to make them as the pattern can be withdrawn from the sand mould without locking. This leads to fairly quick production times.

Forging:

These are a more robust crank than a cast crank for a few reasons.
They are more commonly found in higher stressed engines and come standard in some 16v engines and almost all of the 1.8T engines. I do believe they feature in the new fsi engines too, although I have not yet got the pleasure of getting my hands on one>yet.

A forge crank is made in a totally different way to a cast one.

A set of dies are machined to the approximate shape of the crankshaft as below.

The dies are pressed together until the limit stops on the dies come into contact, once this happens the blank has been completely pressed and any excess is squeezed out the gap between the dies. It is this excess metal, or flash that makes a forged crank very easy to recognise. This flash is quite thick, sometimes as much as 10mm, as a result it has to be ground off before any finish machining can be done. This so called part line then ends up being quite wide and can be recognised instantly over a cast cranks faint part line
 Billet Cranks:
Billet cranks are the best type of crank you can have in your engine if you want to get the most from it.

They start off again as a very high grade steel containing all the correct alloys needed to meet the demands. 4340 steel is normally used which contains nickel, chromium, aluminium, and molybdenum amongst other elements.

The Steel blank is then forged to align the grain and compact all the molecules closer together as in the case of the forged crank.

The dense blank is then ready for machining.

Here you can see a billet crank in various stages of production, it is from a Ferrari

videos:
http://www.youtube.com/watch?v=C7rXuaJMhOc
http://www.clubgti.com/forum/showthread.php?t=215166

Camshaft

                                                                camshaft                 

                                                                                                                                                                  A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part

Material:

Camshafts can be made out of several different types of material. These include

1. Chilled iron castings
2. Billet Steel

Timing:

The relationship between the rotation of the camshaft and the rotation of the crankshaft is of critical importance. Since the valves control the flow of the air/fuel mixture intake and exhaust gases, they must be opened and closed at the appropriate time during the stroke of the piston. For this reason, the camshaft is connected to the crankshafteither directly, via a gear mechanism, or indirectly via a belt or chain called a timing belt or timing chain. Direct drive using gears is unusual because the frequently reversing torque caused by the slope of the cams tends to quickly wear out gear teeth. Where gears are used, they tend to be made from resilient fibre rather than metal, except in racing engines that have a high maintenance routine. Fibre gears have a short life span and must be replaced regularly, much like a cam belt. In some designs the camshaft also drives the distributor and the oil and fuel pumps. Some vehicles may have the power steering pump driven by the camshaft

Duration:

Duration is the number of crankshaft degrees of engine rotation during which the valve is off the seat. As a generality, greater duration results in more horsepower. The RPM at which peak horsepower occurs is typically increased as duration increases at the expense of lower rpm efficiency (torque).

Duration can often be confusing because manufacturers may select any lift point to advertise a camshaft's duration and sometimes will manipulate these numbers

Lift:

The camshaft "lift" is the resultant net rise of the valve from its seat. The further the valve rises from its seat the more airflow can be released, which is generally more beneficial. Greater lift has some limitations. Firstly, the lift is limited by the increased proximity of the valve head to the piston crown and secondly greater effort is required to move the valve's springs to higher state of compression. Increased lift can also be limited by lobe clearance in the cylinder head construction, so higher lobes may not necessarily clear the framework of the cylinder head casing. Higher valve lift can have the same effect as increased duration where valve overlap is less desirable

Position:

Depending on the location of the camshaft, the cams operate the valves either directly or through a linkage of pushrods and rockers. Direct operation involves a simpler mechanism and leads to fewer failures, but requires the camshaft to be positioned at the top of the cylinders. In the past when engines were not as reliable as today this was seen as too much bother, but in modern gasoline engines the overhead cam system, where the camshaft is on top of the cylinder head, is quite common.

What Is an Exhaust Valve?

                                                Exhaust Valve:

An exhaust valve is found in the cylinder head of an internal combustion engine. When the fuel and air mixture has been ignited in the cylinder, the spent gasses are sent out of the engine through the exhaust valve. In the typical internal combustion engine, the exhaust valve is larger than the intake valve. This is due to the fact that it is more difficult to clear the cylinder of exhaust gasses than it is to introduce fuel and air into the combustion chamber   

Valves Used In Internal Combustion Engine:

1. Poppet valve

A poppet valve (also called mushroom valve) is a valve typically used to control the timing and quantity of gas or vapour flow into an engineJames Watt was using poppet valves to control the flow of steam into the cylinders of his beam engines in the 1770s. A sectional illustration of Watt's beam engine of 1774 using the device is found in Thurston 1878:98, and Lardner (1840) provides an illustrated description of Watt's use of the poppet valve.

When used in high-pressure applications, for example, as admission valves on steam engines, the same pressure that helps seal poppet valves also contributes significantly to the force required to open them. This has led to the development of the balanced poppet or double beat valve, in which two valve plugs ride on a common stem, with the pressure on one plug largely balancing the pressure on the other. In these valves, the force needed to open the valve is determined by the pressure and the difference between the areas of the two valve openings. Sickels patented a valve gear for double-beat poppet valves in 1842. Criticism was reported in the journal Science in 1889 of equilibrium poppet valves (called by the article the 'double or balanced or American puppet valve') in use for paddle steamer engines, that by its nature it must leak 15 percent.

How to Check Piston Rings

piston rings seal off the pistons in the combustion chamber so that no energy escapes during the compression stroke. Normally, three rings come with each piston: an expansion ring, a compression ring and a thicker oil ring. They work in concert with the piston by riding up and down the cylinder wall with it. Piston rings must maintain a near-perfect seal while subjected to extreme heat, moisture, and sometimes dirty and thinly-polluted oil. For such small and delicate parts, the task they perform harnesses the engine's power output and transfers it to the driving wheels. Anyone can diagnose piston ring problems if they know what to look for

Listen for any noises originating from the sides of the engine or near the oil pan underneath the vehicle. Although connecting rods and bearings can make knocking noises, piston slap has a hollow, bell-like sound, which means the piston rides with too much sideplay inside the cylinder wall. Worn rings can be the cause of this condition.

2

Look for bluish white smoke pouring or intermittently puffing from the exhaust tail pipe. Oil burns with this color, which may be due to worn rings. Valve guides and seals would be the only other parts that would cause excessive oil burn

3.Unhook the coil high-tension wire from the engine. Remove all of the spark plugs with a socket and wrench. Have an assistant crank the engine six or seven times while you take readings on all the cylinders with a compression tester. Write down the pounds per cylinder for each one. Add a small cap of oil to each cylinder and test for compression again. Compare the numbers. If the second test has made the cylinder numbers climb higher than 30 pounds in any cylinder, the rings are worn and should be replaced.

4

Inspect the rings with a magnifying glass once the pistons have been removed from the engine. Look for any dark discoloration on the ring end's outer surface and bottom side. Good rings look shiny and clean in these areas. Bad rings will have soot, oil or carbon buildup.

5

Examine the ends of the rings for lines, scratches or grooves. Such distortions point to metal shavings and/or contaminated oil. Any small pit marks on the ring's outer surface indicates water contamination that has caused rust. The rings must be replaced if this condition exists.

6

Use a feeler gauge to measure the ring gaps when fully open. Consult the manufacturer's specifications in your owner's manual for the correct gap thickness. Generally, too large of a gap allows escaping combustion gases to pass through the ring contact-to-cylinder wall area. A narrow gap indicates the ring has lost flex strength.

7

Look for small amounts of metal slag on the ring's outer surface. Piston rings that show melted edges have been subjected to too much heat. The rings might possibly crack when handled or bent to test their spring-back flexibility. Rings that do not bend easily cannot exert enough tensile strength to make a proper seal.

8

Inspect the largest ring on the bottom of the piston. This is the oil ring, which has an internal structure or weave that allows it to retain oil. The small honeycomb structure should not be caked with carbon or gunk. Replace the ring sets if this condition exists.

9

Examine the rings for uniform thickness. They should not have any thickness variations from one end to the other. A very thin section denotes a cylinder bore that has worn out-of-round or taper, which has distorted the ring's surface. Replace as needed