Making a Car Drift
The first drifting technique a driver needs to master is actually a regular racing technique. Heel-and-toe shifting lets a race car driver downshift smoothly and quickly (to increase rpm) while simultaneously braking (to shift the car's weight forward). The goal of this shifting technique is to maintain equilibrium between engine speed and wheel speed so the drivetrain doesn't jolt while downshifting. To heel-and-toe downshift while your right foot is on the brake, you depress the clutch with your left foot, shift to neutral and release the clutch. Then, keeping the ball of your right foot on the brake, you move your right heel to the gas pedal and rev the engine until the rpm matches up with wheel speed (usually an increase of about 1,500 rpm per one-gear downshift). Once you reach the proper rpm, you get off the gas pedal, still applying the brake, push in the clutch again and downshift. Once a driver can execute proper race-style shifting, she's ready to master some drifting techniques.
Clutch-based techniques
Clutch-kick drift - Approaching the turn, the driver holds in the clutch, increases rpm and downshifts. She then releases the clutch, causing a power surge that makes the back wheels lose traction. This is a basic drifting technique.
Shift-lock drift - Approaching the turn, the driver downshifts and drops the rpm to slow down the drivetrain. She then releases the clutch, causing the back wheels to immediately slow down and lock up so they lose traction.
Brake-based techniques
E-brake drift - The driver enters the turn and pulls the emergency brake to lock the back wheels. She steers into the turn, and the back end swings out into a drift. This is a basic drifting technique.
Braking drift - The driver enters the turn and applies the brakes to push the car's weight to the front wheels, causing the back wheels to rise and lose traction. She then uses a combination of braking and shifting to hold the drift without the back wheels locking up.
Long-slide drift - On a long straightaway approaching a turn, at high speed (up to 100 mph / 161 kph), the driver pulls the emergency brake to initiate a long drift and maintains it into the turn.
Other techniques
Power-over drift - The driver accelerates into and through the entire turn to make the back end swing out as the weight shifts on exit. This technique requires a lot of horsepower.
Feint drift - The driver steers the car to the outside of the turn on the approach, pushing the car's weight to outside wheels. She then quickly steers back into the turn. When the car's suspension kicks back, the weight shifts so quickly that the back end flicks out to initiate a drift.
Jump drift - Entering a turn, the driver bounces the inside rear tire over the inner curb to shift the car's weight to the outside wheels and induce traction loss, initiating a drift.
Dynamic drift (Kansei drift) - Entering a turn at high speed, the driver suddenly releases the gas pedal to shift the weight to the front wheels, initiating a drift as the rear tires lose traction.
Swaying drift - A swaying drift is a lot like a feint drift except that it begins on a long straightaway approach to a turn. Once the car starts drifting, the driver uses steering to maintain the drift in the form of a side-to-side swaying of the car's back end
Dirt-drop drift - The driver drops the rear tires off the race course into the dirt. This technique helps initiate a drift, maintain speed to hold a drift through multiple turns or increase the drift angle (see the next section) during a single turn.
Wednesday, May 9, 2007
engines
Engines
[edit] History
A colorized automobile engine
Early internal-combustion engines were used to power farm equipment similar to these models.
The first internal combustion engines did not have compression, but ran on air/fuel mixture sucked or blown in during the first part of the intake stroke.
The most significant distinction between modern internal combustion engines and the early designs is the use of compression and in particular of in-cylinder compression.
1509: Leonardo da Vinci described a compression-less engine.
1673: Christiaan Huygens described a compression-less engine.
[2]
17th century: English inventor Sir Samuel Morland used gunpowder to drive water pumps.
1780's: Alessandro Volta built a toy electric pistol
([5]) in which an electric spark exploded a mixture of air and hydrogen, firing a cork from the end of the gun.
1794: Robert Street built a compression-less engine whose principle of operation would dominate for nearly a century.
1806: Swiss engineer François Isaac de Rivaz built an internal combustion engine powered by a mixture of hydrogen and oxygen.
1823: Samuel Brown patented the first internal combustion engine to be applied industrially. It was compression-less and based on what Hardenberg calls the "Leonardo cycle," which, as this name implies, was already out of date at that time.
1824: French physicist Sadi Carnot established the thermodynamic theory of idealized heat engines. This scientifically established the need for compression to increase the difference between the upper and lower working temperatures.
1826 April 1: The American Samuel Morey received a patent for a compression-less "Gas Or Vapor Engine".
1838: a patent was granted to William Barnet (English). This was the first recorded suggestion of in-cylinder compression.
1854: The Italians Eugenio Barsanti and Felice Matteucci patented the first working efficient internal combustion engine in London (pt. Num. 1072) but did not go into production with it. It was similar in concept to the successful Otto Langen indirect engine, but not so well worked out in detail.
1860: Jean Joseph Etienne Lenoir (1822 - 1900) produced a gas-fired internal combustion engine closely similar in appearance to a horizontal double-acting steam beam engine, with cylinders, pistons, connecting rods, and flywheel in which the gas essentially took the place of the steam. This was the first internal combustion engine to be produced in numbers.
1862: Nikolaus Otto designed an indirect-acting free-piston compression-less engine whose greater efficiency won the support of Langen and then most of the market, which at that time, was mostly for small stationary engines fueled by lighting gas.
1870: In Vienna Siegfried Marcus put the first mobile gasoline engine on a handcart.
1876: Nikolaus Otto working with Gottlieb Daimler and Wilhelm Maybach developed a practical four-stroke cycle (Otto cycle) engine. The German courts, however, did not hold his patent to cover all in-cylinder compression engines or even the four stroke cycle, and after this decision in-cylinder compression became universal.
Karl Benz
1879: Karl Benz, working independently, was granted a patent for his internal combustion engine, a reliable two-stroke gas engine, based on Nikolaus Otto's design of the four-stroke engine. Later Benz designed and built his own four-stroke engine that was used in his automobiles, which became the first automobiles in production.
1882: James Atkinson invented the Atkinson cycle engine. Atkinson’s engine had one power phase per revolution together with different intake and expansion volumes making it more efficient than the Otto cycle.
1891 - Herbert Akroyd Stuart built his oil engine, leasing rights to Hornsby of England to build them. They build the first cold start, compression ignition engines. In 1892, they installed the first ones in a water pumping station. An experimental higher-pressure version produced self-sustaining ignition through compression alone in the same year.
1892: Rudolf Diesel developed his Carnot heat engine type motor burning powdered coal dust.
1893 February 23: Rudolf Diesel received a patent for the diesel engine.
1896: Karl Benz invented the boxer engine, also known as the horizontally opposed engine, in which the corresponding pistons reach top dead centre at the same time, thus balancing each other in momentum.
1900: Rudolf Diesel demonstrated the diesel engine in the 1900 Exposition Universelle (World's Fair) using peanut oil (see biodiesel).
1900: Wilhelm Maybach designed an engine built at Daimler Motoren Gesellschaft—following the specifications of Emil Jellinek—who required the engine to be named Daimler-Mercedes after his daughter. In 1902 automobiles with that engine were put into production by DMG.
[edit] Applications
Internal combustion engines are most commonly used for mobile propulsion in automobiles, equipment, and other portable machinery. In mobile equipment internal combustion is advantageous, since it can provide high power to weight ratios together with excellent fuel energy-density. These engines have appeared in transport in almost all automobiles, trucks, motorcycles, boats, and in a wide variety of aircraft and locomotives, generally using petroleum . Where very high power is required, such as jet aircraft, helicopters and large ships, they appear mostly in the form of turbines.
They are also used for electric generators (i.e. 12 V generators) and by industry.
[edit] Operation
Four-stroke cycle (or Otto cycle)1. intake2. compression3. power4. exhaust
All internal combustion engines depend on the exothermic chemical process of combustion: the reaction of a fuel, typically with air, although other oxidizers such as nitrous oxide may be employed. Also see stoichiometry.
The most common modern fuels are made up of hydrocarbons and are derived from mostly petroleum. These include the fuels known as dieselfuel, gasoline and petroleum gas, and the rarer use of propane gas. Most internal combustion engines designed for gasoline can run on natural gas or liquefied petroleum gases without major modifications except for the fuel delivery components. Liquid and gaseous biofuels, such as Ethanol and biodiesel, a form of diesel fuel that is produced from crops that yield triglycerides such as soy bean oil, can also be used. Some can also run on Hydrogen gas.
All internal combustion engines must achieve ignition in their cylinders to create combustion. Typically engines use either a spark ignition (SI) method or a compression ignition (CI) system. In the past other methods using hot tubes or flames have been used.
[edit] Gasoline Ignition Process
Electrical/Gasoline-type ignition systems (that can also run on other fuels as previously mentioned) generally rely on a combination of a lead-acid battery and an induction coil to provide a high voltage electrical spark to ignite the air-fuel mix in the engine's cylinders. This battery can be recharged during operation using an electricity-generating device, such as an alternator or generator driven by the engine. Gasoline engines take in a mixture of air and gasoline and compress to less than 185 psi and use a spark plug to ignite the mixture when it is compressed by the piston head in each cylinder.
[edit] Diesel Engine Ignition Process
Compression ignition systems, such as the diesel engine and HCCI engines, rely solely on heat and pressure created by the engine in its compression process for ignition. Compression that occurs is usually more than three times higher than a gasoline engine. Diesel engines will take in air only, and shortly before peak compression, a small quantity of diesel fuel is sprayed into the cylinder via a fuel injector that allows the fuel to instantly ignite. HCCI type engines will take in both air and fuel but will continue to rely on an unaided auto-combustion process due to higher pressures and heat. This is also why diesel and HCCI engines are also more susceptible to cold starting issues though they will run just as well in cold weather once started. Most diesels also have battery and charging systems however this system is secondary and is added by manufacturers as luxury for ease of starting, turning fuel on and off which can also be done via a switch or mechanical apparatus, and for running auxiliary electrical components and accessories. Most old engines, however, rely on electrical systems that also control the combustion process to increase efficiency and reduce emissions.
[edit] Energy
Once ignited and burnt, the combustion products, hot gases, have more available energy than the original compressed fuel/air mixture (which had higher chemical energy). The available energy is manifested as high temperature and pressure which can be translated into work by the engine. In a reciprocating engine, the high pressure product gases inside the cylinders drive the engine's pistons.
Once the available energy has been removed, the remaining hot gases are vented (often by opening a valve or exposing the exhaust outlet) and this allows the piston to return to its previous position (Top Dead Center - TDC). The piston can then proceed to the next phase of its cycle, which varies between engines. Any heat not translated into work is normally considered a waste product, and is removed from the engine either by an air or liquid cooling system.
[edit] Parts
An illustration of several key components in a typical four-stroke engine
For a four-stroke engine, key parts of the engine include the crankshaft (purple), one or more camshafts (red and blue) and valves. For a two-stroke engine, there may simply be an exhaust outlet and fuel inlet instead of a valve system. In both types of engines, there are one or more cylinders (grey and green) and for each cylinder there is a spark plug (darker-grey), a piston (yellow) and a crank (purple). A single sweep of the cylinder by the piston in an upward or downward motion is known as a stroke and the downward stroke that occurs directly after the air-fuel mix passes from the carburetor to the the cylinder, where it is ignited; this is known as a power stroke.
A Wankel engine has a triangular rotor that orbits in an epitrochoidal (figure 8 shape) chamber around an eccentric shaft. The four phases of operation (intake, compression, power, exhaust) take place in separate locations, instead of one single location as in a reciprocating engine.
A Bourke Engine uses a pair of pistons integrated to a Scotch Yoke that transmits reciprocating force through a specially designed bearing assembly to turn a crank mechanism. Intake, compression, power, and exhaust occur in each stroke.
[edit] Classification
The fundamental difference between an engine and a motor is that a motor converts electricity into mechanical energy whereas an engine converts thermal energy into mechanical energy. At one time, the word "engine" (from Latin, via Old French, ingenium, "ability") meant any piece of machinery — a sense the persists in expressions such as siege engine. A "motor" (from Latin motor, "mover") is any machine that produces mechanical power. Traditionally, electric motors are not referred to as "engines," but combustion engines are often referred to as "motors." (An electric engine refers to locomotive operated by electricity).
However, many people consider engines as those things which generate their power from within, and motors as requiring an outside source of energy to perform their work.
[edit] Principles of operation
[edit] Beare Head
The Beare Head Six Stroke was named such after its inventor. The Beare Head Six Stroke combines both a four stroke engine bottom end, plus a two stroke slanted top end, thus 4+2= Six Stroke. It is a piston valve with auxiliary low pressure valves. With the hybrid of two- and four-stroke technology, the device supposedly achieves increased torque and power output, better fuel economy and cleaner burning with reduced emissions, longer service intervals, and considerably reduced tooling costs when compared with a conventional OHC four-stroke design.
The technology was sold to an Australian company in 2004 http://www.jack-brabham-engines.com
[edit] Bourke Engine
In this engine, two diametrically opposed cylinders are linked to the crank by the crank pin that goes through the common scotch yoke. The cylinders and pistons are so constructed that there are, as in the usual two stroke cycle, two power strokes per revolution. However, unlike the common two stroke engine, the burnt gases and the incoming fresh air do not mix in the cylinders, contributing to a cleaner, more efficient operation.
The scotch yoke mechanism also has low side thrust and thus greatly reduces friction between pistons and cylinder walls. The Bourke engine's combustion phase more closely approximates constant volume combustion than either four stroke or two stroke cycles do.
It also uses less moving parts, hence needs to overcome less friction than the other two reciprocating types have to. In addition, its greater expansion ratio also means more of the heat from its combustion phase is utilized than is used by either four stroke or two stroke cycles.
[edit] Controlled Combustion Engine
These are also cylinder based engines and may be either single- or two-stroke but use, instead of a crankshaft and piston rods, two gear connected, counter rotating concentric cams to convert reciprocating motion into rotary movement.
These cams practically cancel out sideward forces that would otherwise be exerted on the cylinders by the pistons, greatly improving mechanical efficiency.
The number of lobes of the cams (always an odd number not less than 3) determines the piston travel versus the torque delivered. In this engine, there are two cylinders that are 180 degrees apart for each pair of counter-rotating cams. For single-stroke versions there are as many cycles per cylinder pair as there are lobes on each cam, and twice as many for two-stroke engines.
[edit] Wankel
Main article: Wankel engine
The Wankel engine (Rotary engine) does not have piston strokes so is more properly called a four-phase than a four-stroke engine.
It operates with the same separation of phases as the four-stroke engine, with the phases taking place in separate locations in the engine. This engine provides three power 'strokes' per revolution per rotor, typically giving it a greater power-to-weight ratio than piston engines. This type of engine is most notably used in the current Mazda RX-8, the earlier RX-7, and other models.
[edit] Gas turbine
Main article: Gas turbine
Gas turbines cycles (notably jet engines), do not use the same piston to compress and then expand the gases; instead separate compressors and gas turbines are employed; giving continuous power.
Essentially, the intake gas (normally air) is compressed, and then combusted with a fuel, which greatly raises the temperature and volume. The larger volume of hot gas from the combustion chamber is then fed through the gas turbine which is then easily able to power the compressor. The exhaust gas may be used to provide thrust, supplying only sufficient power to the turbine to compress incoming air (jet engine); or as much energy as possible can be supplied to the turbine (gas turbine proper).
[edit] Disused methods
In some old non-compressing internal combustion engines: In the first part of the piston downstroke a fuel/air mixture was sucked or blown in.
In the rest of the piston downstroke the inlet valve closed and the fuel/air mixture fired. In the piston upstroke the exhaust valve was open. This was an attempt at imitating the way a piston steam engine works.
[edit] Fuels and oxidizers
Fuels used include petroleum spirit (North American term: gasoline, British term: petrol), autogas (liquified petroleum gas), compressed natural gas, hydrogen, diesel fuel, jet fuel, landfill gas, biodiesel, biobutanol, peanut oil and other vegoils, bioethanol, biomethanol (methyl or wood alcohol) and other biofuels.
Even fluidised metal powders and explosives have seen some use. Engines that use gases for fuel are called gas engines and those that use liquid hydrocarbons are called oil engines. However, gasoline engines are also often colloquially referred to as 'gas engines'.
The main limitations on fuels are that it must be easily transportable through the fuel system to the combustion chamber, and that the fuel release sufficient energy in the form of heat upon combustion to make use of the engine practical.
The oxidiser is typically air, and has the advantage of not being stored within the vehicle, increasing the power-to-weight ratio. Air can, however, be compressed and carried aboard a vehicle. Some submarines are designed to carry pure oxygen or hydrogen peroxide so that they do not need air from the atmosphere. Some race cars carry nitrous oxide as oxidizer. Other chemicals such as chlorine or fluorine have been used experimentally, but have not been found to be practical.
Diesel engines are generally heavier, noisier and more powerful at lower speeds than gasoline engines. They are also more fuel-efficient in most circumstances and are used in heavy road vehicles, some automobiles (increasingly so for their increased fuel efficiency over gasoline engines), ships, railway locomotives, and light aircraft.
Gasoline engines are used in most other road vehicles including most cars, motorcycles and mopeds. Note that in Europe, sophisticated diesel-engined cars have taken over about 40% of the market since the 1990s. There are also engines that run on hydrogen, methanol, ethanol, liquefied petroleum gas (LPG) and biodiesel. Paraffin and tractor vaporising oil (TVO) engines are no longer seen.
[edit] Hydrogen engine
Some have theorized that in the future hydrogen might replace such fuels. Furthermore, with the introduction of hydrogen fuel cell technology, the use of internal combustion engines may be phased out. The advantage of hydrogen is that its combustion produces only water.
This is unlike the combustion of fossil fuels, which produce carbon dioxide, a known green house gas GHG, carbon monoxide resulting from incomplete combustion, and other local and atmospheric pollutants such as sulfur dioxide and nitrogen oxides that lead to urban respiratory problems, acid rain, and ozone gas problems.
However, free hydrogen for fuel does not occur naturally, burning it liberates less energy than it takes to produce hydrogen in the first place due to the second law of thermodynamics.
Although there are multiple ways of producing free hydrogen, those require converting combustible molecules into hydrogen, so hydrogen does not solve any energy crisis, moreover, it only addresses the issue of portability and some pollution issues.
The disadvantage of hydrogen in many situations is its storage. Liquid hydrogen has extremely low density- 14 times lower than water and requires extensive insulation, whilst gaseous hydrogen requires heavy tankage.
Although hydrogen has a higher specific energy, the volumetric energetic storage is still roughly five times lower than petrol, even when liquified. (The 'Hydrogen on Demand' process, designed by Steven Amendola, creates hydrogen as it is needed, but has other issues, such as the high price of the sodium borohydride, the raw material. Sodium borohydride is renewable and could become cheaper if more widely produced.)
[edit] History
A colorized automobile engine
Early internal-combustion engines were used to power farm equipment similar to these models.
The first internal combustion engines did not have compression, but ran on air/fuel mixture sucked or blown in during the first part of the intake stroke.
The most significant distinction between modern internal combustion engines and the early designs is the use of compression and in particular of in-cylinder compression.
1509: Leonardo da Vinci described a compression-less engine.
1673: Christiaan Huygens described a compression-less engine.
[2]
17th century: English inventor Sir Samuel Morland used gunpowder to drive water pumps.
1780's: Alessandro Volta built a toy electric pistol
([5]) in which an electric spark exploded a mixture of air and hydrogen, firing a cork from the end of the gun.
1794: Robert Street built a compression-less engine whose principle of operation would dominate for nearly a century.
1806: Swiss engineer François Isaac de Rivaz built an internal combustion engine powered by a mixture of hydrogen and oxygen.
1823: Samuel Brown patented the first internal combustion engine to be applied industrially. It was compression-less and based on what Hardenberg calls the "Leonardo cycle," which, as this name implies, was already out of date at that time.
1824: French physicist Sadi Carnot established the thermodynamic theory of idealized heat engines. This scientifically established the need for compression to increase the difference between the upper and lower working temperatures.
1826 April 1: The American Samuel Morey received a patent for a compression-less "Gas Or Vapor Engine".
1838: a patent was granted to William Barnet (English). This was the first recorded suggestion of in-cylinder compression.
1854: The Italians Eugenio Barsanti and Felice Matteucci patented the first working efficient internal combustion engine in London (pt. Num. 1072) but did not go into production with it. It was similar in concept to the successful Otto Langen indirect engine, but not so well worked out in detail.
1860: Jean Joseph Etienne Lenoir (1822 - 1900) produced a gas-fired internal combustion engine closely similar in appearance to a horizontal double-acting steam beam engine, with cylinders, pistons, connecting rods, and flywheel in which the gas essentially took the place of the steam. This was the first internal combustion engine to be produced in numbers.
1862: Nikolaus Otto designed an indirect-acting free-piston compression-less engine whose greater efficiency won the support of Langen and then most of the market, which at that time, was mostly for small stationary engines fueled by lighting gas.
1870: In Vienna Siegfried Marcus put the first mobile gasoline engine on a handcart.
1876: Nikolaus Otto working with Gottlieb Daimler and Wilhelm Maybach developed a practical four-stroke cycle (Otto cycle) engine. The German courts, however, did not hold his patent to cover all in-cylinder compression engines or even the four stroke cycle, and after this decision in-cylinder compression became universal.
Karl Benz
1879: Karl Benz, working independently, was granted a patent for his internal combustion engine, a reliable two-stroke gas engine, based on Nikolaus Otto's design of the four-stroke engine. Later Benz designed and built his own four-stroke engine that was used in his automobiles, which became the first automobiles in production.
1882: James Atkinson invented the Atkinson cycle engine. Atkinson’s engine had one power phase per revolution together with different intake and expansion volumes making it more efficient than the Otto cycle.
1891 - Herbert Akroyd Stuart built his oil engine, leasing rights to Hornsby of England to build them. They build the first cold start, compression ignition engines. In 1892, they installed the first ones in a water pumping station. An experimental higher-pressure version produced self-sustaining ignition through compression alone in the same year.
1892: Rudolf Diesel developed his Carnot heat engine type motor burning powdered coal dust.
1893 February 23: Rudolf Diesel received a patent for the diesel engine.
1896: Karl Benz invented the boxer engine, also known as the horizontally opposed engine, in which the corresponding pistons reach top dead centre at the same time, thus balancing each other in momentum.
1900: Rudolf Diesel demonstrated the diesel engine in the 1900 Exposition Universelle (World's Fair) using peanut oil (see biodiesel).
1900: Wilhelm Maybach designed an engine built at Daimler Motoren Gesellschaft—following the specifications of Emil Jellinek—who required the engine to be named Daimler-Mercedes after his daughter. In 1902 automobiles with that engine were put into production by DMG.
[edit] Applications
Internal combustion engines are most commonly used for mobile propulsion in automobiles, equipment, and other portable machinery. In mobile equipment internal combustion is advantageous, since it can provide high power to weight ratios together with excellent fuel energy-density. These engines have appeared in transport in almost all automobiles, trucks, motorcycles, boats, and in a wide variety of aircraft and locomotives, generally using petroleum . Where very high power is required, such as jet aircraft, helicopters and large ships, they appear mostly in the form of turbines.
They are also used for electric generators (i.e. 12 V generators) and by industry.
[edit] Operation
Four-stroke cycle (or Otto cycle)1. intake2. compression3. power4. exhaust
All internal combustion engines depend on the exothermic chemical process of combustion: the reaction of a fuel, typically with air, although other oxidizers such as nitrous oxide may be employed. Also see stoichiometry.
The most common modern fuels are made up of hydrocarbons and are derived from mostly petroleum. These include the fuels known as dieselfuel, gasoline and petroleum gas, and the rarer use of propane gas. Most internal combustion engines designed for gasoline can run on natural gas or liquefied petroleum gases without major modifications except for the fuel delivery components. Liquid and gaseous biofuels, such as Ethanol and biodiesel, a form of diesel fuel that is produced from crops that yield triglycerides such as soy bean oil, can also be used. Some can also run on Hydrogen gas.
All internal combustion engines must achieve ignition in their cylinders to create combustion. Typically engines use either a spark ignition (SI) method or a compression ignition (CI) system. In the past other methods using hot tubes or flames have been used.
[edit] Gasoline Ignition Process
Electrical/Gasoline-type ignition systems (that can also run on other fuels as previously mentioned) generally rely on a combination of a lead-acid battery and an induction coil to provide a high voltage electrical spark to ignite the air-fuel mix in the engine's cylinders. This battery can be recharged during operation using an electricity-generating device, such as an alternator or generator driven by the engine. Gasoline engines take in a mixture of air and gasoline and compress to less than 185 psi and use a spark plug to ignite the mixture when it is compressed by the piston head in each cylinder.
[edit] Diesel Engine Ignition Process
Compression ignition systems, such as the diesel engine and HCCI engines, rely solely on heat and pressure created by the engine in its compression process for ignition. Compression that occurs is usually more than three times higher than a gasoline engine. Diesel engines will take in air only, and shortly before peak compression, a small quantity of diesel fuel is sprayed into the cylinder via a fuel injector that allows the fuel to instantly ignite. HCCI type engines will take in both air and fuel but will continue to rely on an unaided auto-combustion process due to higher pressures and heat. This is also why diesel and HCCI engines are also more susceptible to cold starting issues though they will run just as well in cold weather once started. Most diesels also have battery and charging systems however this system is secondary and is added by manufacturers as luxury for ease of starting, turning fuel on and off which can also be done via a switch or mechanical apparatus, and for running auxiliary electrical components and accessories. Most old engines, however, rely on electrical systems that also control the combustion process to increase efficiency and reduce emissions.
[edit] Energy
Once ignited and burnt, the combustion products, hot gases, have more available energy than the original compressed fuel/air mixture (which had higher chemical energy). The available energy is manifested as high temperature and pressure which can be translated into work by the engine. In a reciprocating engine, the high pressure product gases inside the cylinders drive the engine's pistons.
Once the available energy has been removed, the remaining hot gases are vented (often by opening a valve or exposing the exhaust outlet) and this allows the piston to return to its previous position (Top Dead Center - TDC). The piston can then proceed to the next phase of its cycle, which varies between engines. Any heat not translated into work is normally considered a waste product, and is removed from the engine either by an air or liquid cooling system.
[edit] Parts
An illustration of several key components in a typical four-stroke engine
For a four-stroke engine, key parts of the engine include the crankshaft (purple), one or more camshafts (red and blue) and valves. For a two-stroke engine, there may simply be an exhaust outlet and fuel inlet instead of a valve system. In both types of engines, there are one or more cylinders (grey and green) and for each cylinder there is a spark plug (darker-grey), a piston (yellow) and a crank (purple). A single sweep of the cylinder by the piston in an upward or downward motion is known as a stroke and the downward stroke that occurs directly after the air-fuel mix passes from the carburetor to the the cylinder, where it is ignited; this is known as a power stroke.
A Wankel engine has a triangular rotor that orbits in an epitrochoidal (figure 8 shape) chamber around an eccentric shaft. The four phases of operation (intake, compression, power, exhaust) take place in separate locations, instead of one single location as in a reciprocating engine.
A Bourke Engine uses a pair of pistons integrated to a Scotch Yoke that transmits reciprocating force through a specially designed bearing assembly to turn a crank mechanism. Intake, compression, power, and exhaust occur in each stroke.
[edit] Classification
The fundamental difference between an engine and a motor is that a motor converts electricity into mechanical energy whereas an engine converts thermal energy into mechanical energy. At one time, the word "engine" (from Latin, via Old French, ingenium, "ability") meant any piece of machinery — a sense the persists in expressions such as siege engine. A "motor" (from Latin motor, "mover") is any machine that produces mechanical power. Traditionally, electric motors are not referred to as "engines," but combustion engines are often referred to as "motors." (An electric engine refers to locomotive operated by electricity).
However, many people consider engines as those things which generate their power from within, and motors as requiring an outside source of energy to perform their work.
[edit] Principles of operation
[edit] Beare Head
The Beare Head Six Stroke was named such after its inventor. The Beare Head Six Stroke combines both a four stroke engine bottom end, plus a two stroke slanted top end, thus 4+2= Six Stroke. It is a piston valve with auxiliary low pressure valves. With the hybrid of two- and four-stroke technology, the device supposedly achieves increased torque and power output, better fuel economy and cleaner burning with reduced emissions, longer service intervals, and considerably reduced tooling costs when compared with a conventional OHC four-stroke design.
The technology was sold to an Australian company in 2004 http://www.jack-brabham-engines.com
[edit] Bourke Engine
In this engine, two diametrically opposed cylinders are linked to the crank by the crank pin that goes through the common scotch yoke. The cylinders and pistons are so constructed that there are, as in the usual two stroke cycle, two power strokes per revolution. However, unlike the common two stroke engine, the burnt gases and the incoming fresh air do not mix in the cylinders, contributing to a cleaner, more efficient operation.
The scotch yoke mechanism also has low side thrust and thus greatly reduces friction between pistons and cylinder walls. The Bourke engine's combustion phase more closely approximates constant volume combustion than either four stroke or two stroke cycles do.
It also uses less moving parts, hence needs to overcome less friction than the other two reciprocating types have to. In addition, its greater expansion ratio also means more of the heat from its combustion phase is utilized than is used by either four stroke or two stroke cycles.
[edit] Controlled Combustion Engine
These are also cylinder based engines and may be either single- or two-stroke but use, instead of a crankshaft and piston rods, two gear connected, counter rotating concentric cams to convert reciprocating motion into rotary movement.
These cams practically cancel out sideward forces that would otherwise be exerted on the cylinders by the pistons, greatly improving mechanical efficiency.
The number of lobes of the cams (always an odd number not less than 3) determines the piston travel versus the torque delivered. In this engine, there are two cylinders that are 180 degrees apart for each pair of counter-rotating cams. For single-stroke versions there are as many cycles per cylinder pair as there are lobes on each cam, and twice as many for two-stroke engines.
[edit] Wankel
Main article: Wankel engine
The Wankel engine (Rotary engine) does not have piston strokes so is more properly called a four-phase than a four-stroke engine.
It operates with the same separation of phases as the four-stroke engine, with the phases taking place in separate locations in the engine. This engine provides three power 'strokes' per revolution per rotor, typically giving it a greater power-to-weight ratio than piston engines. This type of engine is most notably used in the current Mazda RX-8, the earlier RX-7, and other models.
[edit] Gas turbine
Main article: Gas turbine
Gas turbines cycles (notably jet engines), do not use the same piston to compress and then expand the gases; instead separate compressors and gas turbines are employed; giving continuous power.
Essentially, the intake gas (normally air) is compressed, and then combusted with a fuel, which greatly raises the temperature and volume. The larger volume of hot gas from the combustion chamber is then fed through the gas turbine which is then easily able to power the compressor. The exhaust gas may be used to provide thrust, supplying only sufficient power to the turbine to compress incoming air (jet engine); or as much energy as possible can be supplied to the turbine (gas turbine proper).
[edit] Disused methods
In some old non-compressing internal combustion engines: In the first part of the piston downstroke a fuel/air mixture was sucked or blown in.
In the rest of the piston downstroke the inlet valve closed and the fuel/air mixture fired. In the piston upstroke the exhaust valve was open. This was an attempt at imitating the way a piston steam engine works.
[edit] Fuels and oxidizers
Fuels used include petroleum spirit (North American term: gasoline, British term: petrol), autogas (liquified petroleum gas), compressed natural gas, hydrogen, diesel fuel, jet fuel, landfill gas, biodiesel, biobutanol, peanut oil and other vegoils, bioethanol, biomethanol (methyl or wood alcohol) and other biofuels.
Even fluidised metal powders and explosives have seen some use. Engines that use gases for fuel are called gas engines and those that use liquid hydrocarbons are called oil engines. However, gasoline engines are also often colloquially referred to as 'gas engines'.
The main limitations on fuels are that it must be easily transportable through the fuel system to the combustion chamber, and that the fuel release sufficient energy in the form of heat upon combustion to make use of the engine practical.
The oxidiser is typically air, and has the advantage of not being stored within the vehicle, increasing the power-to-weight ratio. Air can, however, be compressed and carried aboard a vehicle. Some submarines are designed to carry pure oxygen or hydrogen peroxide so that they do not need air from the atmosphere. Some race cars carry nitrous oxide as oxidizer. Other chemicals such as chlorine or fluorine have been used experimentally, but have not been found to be practical.
Diesel engines are generally heavier, noisier and more powerful at lower speeds than gasoline engines. They are also more fuel-efficient in most circumstances and are used in heavy road vehicles, some automobiles (increasingly so for their increased fuel efficiency over gasoline engines), ships, railway locomotives, and light aircraft.
Gasoline engines are used in most other road vehicles including most cars, motorcycles and mopeds. Note that in Europe, sophisticated diesel-engined cars have taken over about 40% of the market since the 1990s. There are also engines that run on hydrogen, methanol, ethanol, liquefied petroleum gas (LPG) and biodiesel. Paraffin and tractor vaporising oil (TVO) engines are no longer seen.
[edit] Hydrogen engine
Some have theorized that in the future hydrogen might replace such fuels. Furthermore, with the introduction of hydrogen fuel cell technology, the use of internal combustion engines may be phased out. The advantage of hydrogen is that its combustion produces only water.
This is unlike the combustion of fossil fuels, which produce carbon dioxide, a known green house gas GHG, carbon monoxide resulting from incomplete combustion, and other local and atmospheric pollutants such as sulfur dioxide and nitrogen oxides that lead to urban respiratory problems, acid rain, and ozone gas problems.
However, free hydrogen for fuel does not occur naturally, burning it liberates less energy than it takes to produce hydrogen in the first place due to the second law of thermodynamics.
Although there are multiple ways of producing free hydrogen, those require converting combustible molecules into hydrogen, so hydrogen does not solve any energy crisis, moreover, it only addresses the issue of portability and some pollution issues.
The disadvantage of hydrogen in many situations is its storage. Liquid hydrogen has extremely low density- 14 times lower than water and requires extensive insulation, whilst gaseous hydrogen requires heavy tankage.
Although hydrogen has a higher specific energy, the volumetric energetic storage is still roughly five times lower than petrol, even when liquified. (The 'Hydrogen on Demand' process, designed by Steven Amendola, creates hydrogen as it is needed, but has other issues, such as the high price of the sodium borohydride, the raw material. Sodium borohydride is renewable and could become cheaper if more widely produced.)
Hyundai Veracruz
That's No Lexus, It's a Hyundai
2007 Hyundai Veracruz
Forget the myth. Hyundai Motor is not a tiny South Korean manufacturer of cheap little cars. It is a giant -- the largest car company in South Korea and, as a part of the Hyundai Kia Automotive Group, the sixth-largest car company in the world.
It is a threat to anyone making cars, economy or luxury.
It can topple General Motors. It can upset Toyota. It already has bypassed Nissan and Honda in global vehicle sales. It is as determined as any company to rank No. 1 on the world's automotive stage.
You can be forgiven for being surprised. Until now, Hyundai has done well faking humility -- rolling out economy cars, wagons and compact sport-utility vehicles for budget-minded consumers. It will continue to serve that segment. Money is money. But there is more money to be made serving the rich -- upper-income professionals who traditionally shop Audi, BMW, Cadillac, Infiniti, Lexus, Lincoln or Mercedes-Benz.
Hyundai wants those upscale dollars and is implementing an audacious, risky strategy to get them. It plans to build better luxury vehicles than any existing competitor and to sell those models at prices below that of any segment rival.
Cheeky? Yes. Possible? Consider the 2007 Hyundai Veracruz Limited crossover utility vehicle, which easily runs against the likes of the excellent Lexus RX350 -- for thousands of dollars less.
I recently did a day-long, head-to-head driving comparison of the Veracruz and RX350 in San Diego and environs. There were obvious differences. The Veracruz, available with all-wheel drive or front-wheel drive, has seating for seven people. The RX350, also available with all-wheel drive or front-wheel drive, has space for five. The Veracruz has more standard equipment -- including some that is usually optional, such as third-row seating -- than the RX350.
In terms of crash-avoidance and impact-mitigation equipment, the Veracruz matches or surpasses all mainstream luxury vehicle manufacturers. For example, electronic stability control, side and head air bags, front-seat active head restraints, rear-seat head restraints, antilock brakes and electronic brake assistance are all standard on the Veracruz.
In design and creature comforts, the Veracruz -- especially the fully loaded Limited edition -- is an undisputed winner. It has a longer, more elegantly sculpted body than the RX350. Inside and out, it simply looks better. Inside, it also feels better -- more spacious, less cramped than the RX350. The leather-covered seats are comfortable. (Thankfully, here, Hyundai jettisoned the notion that all drivers' seats should fit the body as tightly as those in a race car. The Veracruz's seats recognize that many of us are older and that our bodies are slightly larger than they were in our youth.) The Veracruz has every onboard automotive gadget imaginable, except one. At the moment, there is no navigation system. Hyundai has taken some heat for that. And the company is likely to respond by offering onboard navigation as an option in the slightly updated 2008 Veracruz. I understand the concept of the customer always being right. However, in this case, I believe that both Hyundai and its customers are wrong.
Go to a good consumer electronics shop. Look at the portable, easily attachable navigation systems. Most of them are more advanced and more accurate, and have more usable features than the best onboard navigation systems. But the portables, which can be updated more quickly than the fixed onboard models, often sell for half the price.
It thus makes as much sense for car companies to continue installing onboard systems as it does for them to install car phones, which have been surpassed in features, functionality and value by hand-held cellphones. Hyundai needs to save the money it's going to waste installing onboard systems and use it to do something else.
But who am I to talk? Hyundai, as represented by the Veracruz, seems to be doing quite well following its own sense of what's right and what works.
Consider the matter of engineering. The Veracruz comes with an easy-breathing, 260-horsepower, 3.8-liter V-6. It uses regular unleaded fuel. The engine is linked to a remarkably smooth six-speed automatic transmission. The comparable RX350 comes with a 3.5-liter, 270-horsepower V-6 that requires premium unleaded fuel. That engine is linked to a five-speed automatic transmission. Put another way, the Veracruz is less expensive to operate than the RX350. But it's every bit as much fun to drive.
Still, the problem for Hyundai remains consumer perception. It has to get consumers into the Veracruz to make them believe. That won't be easy to do in the luxury vehicle segment. Prestige is important to luxury bias. Fair or not, for the time being, "Lexus" still sounds better than
2007 Hyundai Veracruz
Forget the myth. Hyundai Motor is not a tiny South Korean manufacturer of cheap little cars. It is a giant -- the largest car company in South Korea and, as a part of the Hyundai Kia Automotive Group, the sixth-largest car company in the world.
It is a threat to anyone making cars, economy or luxury.
It can topple General Motors. It can upset Toyota. It already has bypassed Nissan and Honda in global vehicle sales. It is as determined as any company to rank No. 1 on the world's automotive stage.
You can be forgiven for being surprised. Until now, Hyundai has done well faking humility -- rolling out economy cars, wagons and compact sport-utility vehicles for budget-minded consumers. It will continue to serve that segment. Money is money. But there is more money to be made serving the rich -- upper-income professionals who traditionally shop Audi, BMW, Cadillac, Infiniti, Lexus, Lincoln or Mercedes-Benz.
Hyundai wants those upscale dollars and is implementing an audacious, risky strategy to get them. It plans to build better luxury vehicles than any existing competitor and to sell those models at prices below that of any segment rival.
Cheeky? Yes. Possible? Consider the 2007 Hyundai Veracruz Limited crossover utility vehicle, which easily runs against the likes of the excellent Lexus RX350 -- for thousands of dollars less.
I recently did a day-long, head-to-head driving comparison of the Veracruz and RX350 in San Diego and environs. There were obvious differences. The Veracruz, available with all-wheel drive or front-wheel drive, has seating for seven people. The RX350, also available with all-wheel drive or front-wheel drive, has space for five. The Veracruz has more standard equipment -- including some that is usually optional, such as third-row seating -- than the RX350.
In terms of crash-avoidance and impact-mitigation equipment, the Veracruz matches or surpasses all mainstream luxury vehicle manufacturers. For example, electronic stability control, side and head air bags, front-seat active head restraints, rear-seat head restraints, antilock brakes and electronic brake assistance are all standard on the Veracruz.
In design and creature comforts, the Veracruz -- especially the fully loaded Limited edition -- is an undisputed winner. It has a longer, more elegantly sculpted body than the RX350. Inside and out, it simply looks better. Inside, it also feels better -- more spacious, less cramped than the RX350. The leather-covered seats are comfortable. (Thankfully, here, Hyundai jettisoned the notion that all drivers' seats should fit the body as tightly as those in a race car. The Veracruz's seats recognize that many of us are older and that our bodies are slightly larger than they were in our youth.) The Veracruz has every onboard automotive gadget imaginable, except one. At the moment, there is no navigation system. Hyundai has taken some heat for that. And the company is likely to respond by offering onboard navigation as an option in the slightly updated 2008 Veracruz. I understand the concept of the customer always being right. However, in this case, I believe that both Hyundai and its customers are wrong.
Go to a good consumer electronics shop. Look at the portable, easily attachable navigation systems. Most of them are more advanced and more accurate, and have more usable features than the best onboard navigation systems. But the portables, which can be updated more quickly than the fixed onboard models, often sell for half the price.
It thus makes as much sense for car companies to continue installing onboard systems as it does for them to install car phones, which have been surpassed in features, functionality and value by hand-held cellphones. Hyundai needs to save the money it's going to waste installing onboard systems and use it to do something else.
But who am I to talk? Hyundai, as represented by the Veracruz, seems to be doing quite well following its own sense of what's right and what works.
Consider the matter of engineering. The Veracruz comes with an easy-breathing, 260-horsepower, 3.8-liter V-6. It uses regular unleaded fuel. The engine is linked to a remarkably smooth six-speed automatic transmission. The comparable RX350 comes with a 3.5-liter, 270-horsepower V-6 that requires premium unleaded fuel. That engine is linked to a five-speed automatic transmission. Put another way, the Veracruz is less expensive to operate than the RX350. But it's every bit as much fun to drive.
Still, the problem for Hyundai remains consumer perception. It has to get consumers into the Veracruz to make them believe. That won't be easy to do in the luxury vehicle segment. Prestige is important to luxury bias. Fair or not, for the time being, "Lexus" still sounds better than
toyota corolla
Nothing Flashy, But It Still Shines on the Road
2007 Toyota Corolla Sport
WEST PALM BEACH, Fla. The car-rental people now call the venerable Toyota Corolla a "midsize" sedan. I suppose they're right. Since its introduction in the United States 40 years ago, the Corolla has undergone myriad changes -- from subcompact to compact to midsize, from sedan only to wagon and sedan and back to wagon, and from the best little car available in America to one now surrounded by multiple rivals, many of them just as good, or demonstrably better, and some of them sold for less money.
Still, when flying into a new city, I'm always happy to stop at the airport's car-rental counter, as I did on arrival here, and ask for a Corolla
Auto industry analysts predict that sales of minivans will not top 1 million again.
Toyota executives, at an international motor show in Geneva last year, declared the minivan "dead." General Motors and Ford are pulling out of the minivan business in 2007, leaving the segment to their lone American rival, the Chrysler Group.
But all is not lost for consumers in need of big family haulers. A new vehicle segment is rising. Auto industry people call it the "crossover" market -- a name that seems more appropriate for a group baptism at a religious revival than it does for a vehicle of any sort.
I prefer calling the new models tall wagons, because that is what they are -- wagons with sport-utility-vehicle pretensions. And here in the seat of San Benito County, along roads winding through the vineyards and agricultural fields of central California, I had the opportunity to drive what arguably is one of the best of the new breed -- the 2007 GMC Acadia.
I was not surprised by the Acadia's road performance or build quality. It shares a platform with the 2007 Saturn Outlook, a tall wagon I drove and wrote about in this space two weeks ago.
I loved the Outlook, a commodious work of unitized steel construction that drove and handled in the manner of a much smaller, tighter sedan, although it offered ample seating for eight people with enough space remaining behind the third upright seat to accommodate 19.7 cubic feet of cargo.
The Acadia has the same capabilities; and I have every reason to believe that the Buick Enclave, which I have not driven but is built on the same tall-wagon platform, will prove to be as capable as its siblings, all of which are available with either front-wheel drive or all-wheel drive.
What, then, distinguishes these three?
In the bad old days of General Motors, the answer would have been easy -- absolutely nothing, with the meager exceptions of their identity badges.
But that GM is dead and gone -- and good riddance to it. The new GM has mastered the art of computerized engineering and design. It has discovered what many of its better foreign rivals have long known -- that with the right sculpting and component tweaks, consumers can be offered visually and behaviorally distinctive vehicles built on the same cost-efficient platform.
Thus, the Acadia, with its bold but tasteful upscale trim, its enhanced four-wheel suspension and its array of electronic gadgetry, such as a heads-up display system that projects vehicle speed and other operational information on the windshield, looks and feels richer than the Outlook. Its exterior design, in keeping with the heritage of GM's GMC Truck Division, is more aggressive than that of the Outlook.
The Buick Enclave, on the other hand, has a look that is jazzy and upscale, decidedly more urban and urbane than either the Outlook or the Acadia. No one will have trouble telling the three vehicles apart. And it's a safe bet that the Acadia, Enclave, and Outlook buyers will be demographically different.
But they are likely to have two things in common -- their dislike for minivans and their disdain for truck-like sport-utility vehicles.
And something else: Buyers of the Acadia and its tall-wagon relatives will have a keen appreciation for style. After all, that is what the turn away from minivans to what the industry calls "crossovers" is all about -- style augmented by performance, reliability, safety, utility and fuel economy.
The tall wagons, or crossovers, have it. The minivans don't.
gmc acadia
A Sweet Toy, but Don't Play Too Long n Brown
The 2007 SLK 350 Roadster sells slowly in comparison with its Mercedes-Benz siblings. That's understandable. It's expensive and frightfully impractical. It accommodates two people, but not much of their stuff. Long-distance drives in this little car will leave you and your passenger stiff and grumpy. If you started out as spouses, best friends or lovers, there's a good chance you might not remain that way by the end of your journey in the roadster.
But on a beautiful spring day when nature and love are in bloom, the SLK 350 is a motorized aphrodisiac. It's stunningly attractive, especially with the convertible hardtop down. It's fast. It's sexy.
Slip a Sergio Mendes disc into the CD player. Push back the electronic lever that controls the hardtop. Crank the volume . . . modestly. Find a curvy road.
Alone, or with company, the SLK 350 is a marvelous car to drive as long as you don't ask it to do what it was not designed to do comfortably -- take you round-trip 300 miles in one day. The power-adjustable seats are the main problem.
There isn't much space inside the SLK 350's cabin. That means if you are accustomed to leaning back a bit as you caress the steering wheel, forget it. The driver's seat, for example, keeps your body upright, whether you want to be upright or not. (I felt like I was back in seventh grade at Holy Redeemer Elementary School in New Orleans facing Sister Vincent, her little round spanking rod and her stern admonitions to "Sit up, Warren!") I could take that punishment for 50 miles or so in the SLK 350. In fact, on short trips, being in this rear-wheel-drive runner does not feel like punishment at all. It's downright fun! The six-speed manual shifter fits nicely in hand. The shift throws are short, precise -- absolutely no hunting or fumbling around for the right gear. The car is wonderfully responsive to the driver's directions.
But much of that driving glory fades when reality intrudes, such as getting stuck in traffic jams on narrow roads in Fairfax County. Your shift arm gets tired of shifting. Sitting upright becomes a day with Sister Vincent: "Straighten up! Lift that head! Both hands on your desk!
"Stop that fidgeting!"
In the SLK 350, I was trying, but I could not comply. I wanted to get out. I was so happy when I turned into my driveway in Arlington I vowed never to leave it again -- at least not in the SLK 350.
My assistant, Ria Manglapus, had a different experience. She's short. She's small. The cramped, but elegant SLK 350 cabin and its sit-up-straight driver's seat did not bother her. "This is a fun car," she said. "I love it!"
Of course, she did. She's a mother of two boys. She's accustomed to carting them, their many cousins, their many friends and all of their stuff around in her 2003 Honda Odyssey minivan.
By comparison, the delightfully selfish, you've-earned-this, you-deserve-this SLK 350 was a dream. It made Ria feel so good, she scheduled a haircut during the two days she had the car. But reality cut short her roadster fun, too. "Gotta take the boys to school, and this won't work," she said upon returning the SLK 350.
And maybe that's the point: It's not supposed to do taxi work. The SLK 350 is a toy, an escape from hauling the world's daily cares. It is the essence of luxury -- splendidly extravagant, totally unnecessary and good for nothing much except bringing a smile to your face as you round a curve or take a corner in complete confidence.
That it lacks long-trip comfort is a plebeian complaint, the kind of bah-humbug mumbled by people like me, who often can afford only one vehicle to handle all transportation duties -- hauling five or more passengers and their stuff comfortably on trips of all durations.
To the SLK 350, that is base work. The car's sole existence for being is to provide intense moments of sheer driving pleasure. That's "moments," not hours or long days. The patricians who can afford the SLK 350 understand that. If they must travel 300 miles or so, they'd hire a limousine, or hop the first-class coach of a train or jet.
And so, for all of you to whom such class distinctions are important, here is how you can tell a driver who can afford the SLK 350 versus the one who has borrowed it, or is struggling to make the car payments: The poseur drives the SLK 350 everywhere all the time, treating it like a commuter, which it really isn't.
Shell backs Ferrari 60th anniversary celebrations
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