Common Rail System

The common rail system accumulates high-pressure fuel in the common rail and injects the fuel into the engine cylinder at timing controlled by the engine ECU, allowing high-pressure injection independent from the engine speed. As a result, the common rail system can reduce harmful materials such as nitrogen oxides (NOx) and particulate matter (PM) in emissions and generates more engine power. DENSO leads the industry in increasing fuel pressure and maximizing the precision of injection timing and quantity, achieving cleaner emissions and more powerful engines. DENSO’s common rail systems are supplied to a variety of vehicles including passenger cars and commercial vehicles. DENSO Technology – Leading the World In 1995, DENSO launched the world’s first common rail system for trucks. In 2002, DENSO launched a 1,800-bar common rail system that achieved the industry’s highest injection pressure, and five-time multiple injections at a high accuracy. This system comfortably cleared EURO4 emission regulations without a diesel particulate filter. Benefits and Features DENSO’s common rail system can inject fuel at up to 1,800 bar, significantly reducing the concentration of PM in emissions. DENSO’s new injectors can perform five injections during each combustion stroke. The five times multiple injections, including pilot injection with a predetermined small fuel quantity, reduce PM and NOx in emissions, and achieve quietness at idling equivalent to gasoline-powered engines. The high fuel injection pressure is generated by the supply pump, which is the lightest in the world for passenger car common rail systems.

diesel engine

internal combus­tion engines designed to convert the chemical energy available in fuel into mechanical energy. This mechanical energy moves pistons up and down inside cylinders. The pistons are connected to a crankshaft, and the up-and-down motion of the pistons, known as linear motion, creates the rotary motion needed to turn the wheels of a car forward. Both diesel engines and gasoline engines covert fuel into energy through a series of small explosions or combustions. The major difference between diesel and gasoline is the way these explosions happen. In a gasoline engine, fuel is mixed with air, compressed by pistons and ignited by sparks from spark plugs. In a diesel engine, however, the air is compressed first, and then the fuel is injected. Because air heats up when it's compressed, the fuel ignites. The diesel engine uses a four-stroke combustion cycle just like a gasoline engine. The four strokes are: Intake stroke -- The intake valve opens up, letting in air and moving the piston down. ­ Compression stroke -- The piston moves back up and compresses the air. Combustion stroke -- As the piston reaches the top, fuel is injected at just the right moment and ignited, forcing the piston back down. Exhaust stroke -- The piston moves back to the top, pushing out the exhaust created from the combustion out of the exhaust valve. Remember that the diesel engine has no spark plug, that it intakes air and compresses it, and that it then injects the fuel directly into the combustion chamber (direct injection). It is the heat of the compressed air that lights the fuel in a diesel engine. In the next section, we'll examine the diesel injection process.

New Turbocharger Ball Bearing Technology

September 4, 2009 --The Comp Turbo CT3B turbocharger is relatively new on the scene, is dynamite in a small package and has a bearing system that utilizes the latest in ball bearing technology. Racing applications need turbochargers that accelerate at the fastest possible rate and the CT3B bearing system allows it to do just that. The acceleration rate of a turbocharger is a function of the rotor inertia and the friction losses in the bearing system. Conventional bearing systems have floating sleeve bearings that have an inner and outer oil film fed by lube oil under pressure from the engine lubricating system. They also must employ a stationary thrust bearing that is also fed by lube oil under pressure from the engine. The friction loss attributed to a stationary thrust bearing is proportional to the fourth power of the radius and can amount to several horsepower at the high speed at which turbochargers operate. The oil films in conventional sleeve bearing systems have significant viscosity that produces appreciable friction losses due to oil film shear when the turbocharger rotor accelerated and running at high speed. The friction losses in the sleeve bearings and in the thrust bearing result in mechanical efficiencies in the middle 90% range in conventional turbochargers. There is little or no oil film shear in ball bearings which operate with rolling friction only so that the CT3B accelerates much faster than turbochargers using sleeve bearings systems. The CT3B bearing system is a proprietary design that is unique in the industry. It utilizes full compliment, angular contact ball bearings with ceramic balls. Compared with steel balls, ceramic balls in ball bearings have a number of advantages. Bearing service life is two to five times longer. They run at lower operating temperatures and allow running speeds to be as much as 50% higher. The surface finish of ceramic balls is almost smooth, producing lower friction losses and lower vibration levels. There is less heat buildup during high speed operation, they exhibit reduced ball skidding and have a longer fatigue life. All these characteristics make ceramic ball bearings ideal for use in turbochargers where they must operate at very high speeds and survive in a high temperature environment. The Full compliment bearings do now use a cage to position the balls and this additional feature, combined with the ceramic material provides a combination that has minimal friction losses. The mechanical efficiency of the CT3B turbo can approach 99%, and this contributes to rotor acceleration rates that have been shown to be faster than competition. The angular contact bearings are mounted in an elongated steel cylinder that is free to rotate in the bearing housing. The outside diameter of the cylinder is fed with lube oil and this outer oil film provides a cushion against shock and vibration. Two angular contact bearings are mounted in tandem on the compressor end of the cylinder in an arrangement that carries rotor thrust in both axial directions. A single angular contact bearing is slid ably mounted under pre- load on the turbine end of the cylinder and is free to move axially with shaft elongation when heat is conducted down the shaft from the hot turbine wheel. The elongated steel cylinder containing the angular contact bearings represents complete bearing system and can be inserted and/or removed as an assembly making the CT3B turbocharger fully upgradeable, serviceable and re-buildable. Racing Applications require a turbocharger that builds boost as rapidly as possible, thus allowing the engine develop high torque at low engine speeds and with boost capability that can produce very high maximum power output .The CT3B turbocharger does exactly that. For example when mounted on one dragster, the CT3B produced 1.7 bar boost in two tenths of a second and developed 650 HP ready for takeoff. Now that’s phenomenal response and very impressive. In street applications, the acceleration rate of a vehicle equipped with a CT3B turbocharger is enhanced and moves the engine out of inefficient operating regimes more rapidly. An improvement in number of gallons of fuel used is the usual result when a vehicle is accelerated faster. Under steady-state operation, the lower HP losses in the CT3B ball bearing system means power is available to the turbocharger compressor which results in higher intake manifold pressure. In most cases, higher boost can make an additional contribution to improving engine fuel consumption. Comp Turbo can supply the CT3B turbocharger with various compressors and turbine wheel trims to tailor its performance so that it matches specific engine application requirements; whether they be racing, street or stationary. In addition, the CT3B will be followed in the near future by other model sized now under development at Comp Turbo. These new models will utilize the proprietary technology that has been designed into the successful CT3B to complete a line of high performance turbochargers utilizing the many advantages of ceramic ball bearings. They will also accelerate like greased lightning to produce the ultimate in engine and vehicle response

2 stroke engine

Stroke: Either the up or down movement of the piston from the top to the bottom or bottom to top of the cylinder (So the piston going from the bottom of the cylinder to the top would be 1 stroke, from the top back to the bottom would be another stroke) Induction: As the piston travels down the cylinder head, it 'sucks' the fuel/air mixture into the cylinder. This is known as 'Induction'. Compression: As the piston travels up to the top of the cylinder head, it 'compresses' the fuel/air mixture from the carburetor in the top of the cylinder head, making the fuel/air mix ready for igniting by the spark plug. This is known as 'Compression'. Ignition: When the spark plug ignites the compressed fuel/air mixture, sometimes referred to as the power stroke. Exhaust: As the piston returns back to the top of the cylinder head after the fuel/air mix has been ignited, the piston pushes the burnt 'exhaust' gases out of the cylinder & through the exhaust system. Transfer Port: The port (or passageway) in a 2 stroke engine that transfers the fuel/air mixture from the bottom of the engine to the top of the cylinder

4 stroke engine

Four Stroke Engine The four stroke engine was first demonstrated by Nikolaus Otto in 1876 hence it is also known as the Otto cycle. The technically correct term is actually four stroke cycle. The four stroke engine is probably the most common engine type nowadays. It powers almost all cars and trucks. The four strokes of the cycle are intake, compression, power, and exhaust. Each corresponds to one full stroke of the piston; therefore, the complete cycle requires two revolutions of the crankshaft to complete. Intake During the intake stroke, the piston moves downward, drawing a fresh charge of vaporized fuel/air mixture. The illustrated engine features a poppet intake valve which is drawn open by the vacuum produced by the intake stroke. Some early engines worked this way; however, most modern engines incorporate an extra cam/lifter arrangement as seen on the exhaust valve. The exhaust valve is held shut by a spring (not illustrated here). Otto compression stroke Compression As the piston rises, the poppet valve is forced shut by the increased cylinder pressure. Flywheel momentum drives the piston upward, compressing the fuel/air mixture. Otto power stroke Power At the top of the compression stroke, the spark plug fires, igniting the compressed fuel. As the fuel burns it expands, driving the piston downward. Otto exhaust stroke Exhaust At the bottom of the power stroke, the exhaust valve is opened by the cam/lifter mechanism. The upward stroke of the piston drives the exhausted fuel out of the cylinder. Ignition System This animation also illustrates a simple ignition system using breaker points, coil, condenser, and battery. A number of visitors have written to point out a problem with the breaker points in my illustration. In this style ignition circuit, the spark plug will fire just as the breaker points open. The illustration appears to have this backwards. In fact, the illustration is correct; it just moves so fast it's difficult to see! Here's a close-up of the frames just at the point the plug fires:

5 stroke engine

Ilmor Engineering, the firm made famous for its work with Indy Cars and Formula One, as well as Triumph Motorcycles and Harley Davidson plus GM, Honda and Mercedes have built an engine that will make you think for a bit, it's a 700cc, 3 cylinder, 130 horsepower turbocharged 5 stroke. Did they say 5 stroke? The 2 outboard cylinders are the high pressure (HP) fired cylinders while the center low pressure (LP) cylinder makes extra use of the exhaust gases. The point of this design is to enable the expansion and compression strokes to be decoupled. The effective expansion ratio is 14.5:1, almost diesel territory, converting the maximum thermal energy into work. The compression ratio can be reduced, delaying knock, without a decrease in performance. The extra expansion stroke of the LP cylinder is, effectively, the 5th stroke. Fuel consumption and emissions levels are similar to that of current diesel engines, without the serious problem of particulate and NOx emissions which plague diesels. Fuel consumption is decreased by 10% over conventional 4 stroke operation. The entire engine is built using conventional technology, no new manufacturing technology or processes are needed. This is more than a computer model, the running prototype is being dyno tested with a second development engine planned for in-vehicle testing. Just when you think the internal combustion engine has pretty well emptied the bag of tricks, a little creative thinking comes along and gets higher fuel efficiency and lower weight than equivalent engines by adding another stroke to the process. So now we have 2, 4, 5 and even 6 strokes. Very impressive engineering, I like it.