INTERNAL COMBUSTION ENGINES

INTERNAL COMBUSTION ENGINESAND THEIRAPPLICATIONS

A PRESENTATION

By

SE MECHANICALA4

SEPTEMBER 2008

An IntroductionThe internal combustion (IC) engine converts chemical energy into useful mechanical energy by burning fuel.Chemical energy is released when the fuel-air mixture is ignited by the spark in the combustion chamber. The gas produced in this reaction rapidly expands forcing the piston down the cylinder on the power stroke.

THE OTTO CYCLE

INLINE 4V6FLAT 4

EXHAUST SYSTEM

PARTS OF ANIC ENGINE

C: Crankshaft E: Exhaust valve cam shaft I: Scavenge air valve cam shaft P: Piston R: Connecting rod S: Spark plug V: Valves. Red: exhaust, Blue: intake W: Cooling water ducts

THE CRANKSHAFT

The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation.

To convert the reciprocating motion into rotation, the crankshaft has "crank throws" or "crankpins"

THE CONNECTING-ROD

In a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft.

The connecting rod was invented sometime between 1174 and 1200

THE CAMSHAFT

The camshaft is an apparatus often used in piston engines to operate poppet valves.

It consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes or cams protruding from it, one for each valve.

PROVIDING DRIVE TO THE CAMSHAFTSAND VARIOUS CAMSHAFT LAYOUTS

POPPET VALVES

THE SPARK PLUG

A spark plug is an electrical device that fits into the cylinder head of internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark.

Internal combustion engines can be divided into spark-ignition engines, which require spark plugs to begin combustion, and compression-ignition engines (diesel engines), which compress the air and then inject diesel fuel into the heated compressed air mixture where it auto-ignites.

Spark plug gapping: The centre electrode (dark rod) is a cylindrical rod, and the top ground electrode (a hook) has square edges. When regapping, the hook is raised or lowered to adjust the gap, often to 0.035 to 0.050 inches.

The main issues with spark plug gaps are:Narrow-Gap risk: spark might be too weak/small to ignite fuel; Narrow-Gap benefit: plug always fires on each cycle; Wide-Gap risk: plug might not fire, or miss at high speeds; Wide-Gap benefit: spark is strong for a clean burn.

A properly gapped plug will be wide enough to burn hot, but not so wide that it skips or misses at high speeds, causing that cylinder to drag, or the engine to begin to rattle.

THE PISTONS

DRIVETRAIN

The drivetrain is the mechanical path by which the engine sends power to the wheels (i.e. provides drive).

The drivetrain includes a gearbox, a power transmission or transfer system i.e. chain and sprocket or drive shaft, a differential, axles, CV joints, wheels and tyres and finally the braking system.

TURBOCHARGERS

Turbochargers are a type of forced induction system which has its compressor powered by a gas turbine running off the exhaust gases from the engine.The purpose of a turbocharger is to increase the mass of air entering the engine to create more power. The compressor whichdrives the turbocharger is powered by a turbine driven by the engines own exhaust gases.

FUEL INTAKE

CARBURETTORA carburettor is a device that blends air and fuel for an internal combustion engine. It was invented by Karl Benzbefore 1885 , patented in 1886. It is colloquially called a carb

FUEL INJECTIONFuel injection is a system for mixing fuel with air in an internal combustion engine. It has become the primary systemused in automotive engines, having almost completely replacedcarburettors in the late 1980s.

TYPICAL EFI (ELECTRONIC FUEL INJECTION) COMPONENTS

Injectors Fuel Pump Fuel Pressure Regulator ECM - Engine Control Module; includes a digital computer and circuitry to communicate with sensors and control outputs. Wiring Harness Various Sensors (Some of the sensors required are listed here.)Crank/Cam Position: Hall effect sensorAirflow: MAF sensor, sometimes inferred with a MAP sensorExhaust Gas Oxygen: Oxygen sensor, EGO sensor, UEGO sensor

OILS AND LUBRICANTS

An internal combustion engine would not run for even a few minutes if the moving parts were allowed to make metal-to-metal contact. The heat generated due to the tremendous amounts of friction would melt the metals, leading to the destruction of the engine. To prevent this, all moving parts ride on a thin film of oil that is pumped between all the moving parts of the engine.

Once between the moving parts, the oil serves two purposes. One purpose is to lubricate the bearing surfaces. The other purpose is to cool the bearings by absorbing the friction-generated heat. The flow of oil to the moving parts is accomplished by the engine's internal lubricating system.

Wankel Rotary Engine

A Rotary Engine is an internal combustion engine, like the engine in your car, but it works in a completely different way than the conventional piston engine. In a piston engine, the same volume of space (the cylinder) alternately does four different jobs: intake, compression, combustion and exhaust.

A rotary engine does these same four jobs, but each one happens in its own part of the housing. It's kind of like having a dedicated cylinder for each of the four jobs, with the piston moving continually from one to the next.

The rotary engine (originally conceived and developed by Dr. Felix Wankel) is sometimes called a Wankel engine, or Wankel rotary engine.

One cycle shownSame process occurring for all sides of body A

Multi-Stroke engines

TWO STROKE ENGINE

Engines based on the two-stroke cycle use two strokes (one up, one down) for every power stroke. Since there are no dedicated intake or exhaust strokes, alternative methods must be used to scavenge the cylinders. The most common method in spark-ignition two-strokes is to use the downward motion of the piston to pressurize fresh charge in the crankcase, which is then blown through the cylinder through ports in the cylinder walls.

Engines based on the five-stroke cycle are a variant of the four-stroke cycle. Normally, the four cycles are intake, compression, combustion, and exhaust. The fifth cycle added by Delautour is refrigeration. Engines running on a five-stroke cycle are claimed to be up to 30% more efficient than equivalent four-stroke engines.

The six stroke engine captures the wasted heat from the four-stroke Otto cycle and creates steam, which simultaneously cools the engine while providing a free power stroke. This removes the need for a cooling system making the engine lighter while giving 40% increased efficiency over the Otto Cycle. Beare Head Technology combines a four-stroke engine bottom-end with a ported cylinder which closely resembles that of a two-stroke: thus, 4+2 equals a six-stroke cycle. It has an opposing piston that acts in unison with auxiliary low pressure reed and rotary valves, which allows variable compression and a range of tuning options.