CAR : Automobile

6/21/2007

Energy


A passenger railroad, taking power through a third rail

Chemical energy is a common independent energy source. Chemical energy is converted to electrical energy, which is then regulated and fed to the drive motors. Chemical energy is usually in the form of diesel or petrol (gasoline). The liquid fuels are usually converted into electricity by an electrical generator powered by an internal combustion engine or other heat engine. This approach is known as diesel-electric or gasoline-electric hybrid locomotion, that produces greenhouse gases.
Another common form of chemical to electrical conversion is by electro-chemical devices. These include fuel cells and batteries. By avoiding an intermediate mechanical step, the conversion efficiency is dramatically improved over the chemical-thermal-mechanical-electrical-mechanical process already discussed. This is due to the higher carnot efficiency through directly oxidizing the fuel and by avoiding several unnecessary energy conversions. Furthermore, electro-chemical batteries conversions are easy to reverse, allowing electrical energy to be stored in chemical form.
Despite the higher efficiency, electro-chemical vehicles have been beset by a technical issue which has prevented them from replacing the more cumbersome heat engines: energy storage. Fuel cells are fragile, sensitive to contamination, and require external reactants such as hydrogen. Batteries currently used are either not mass-produced, leading to high per-unit prices, or end up being a significant (25%-50%) portion of the final vehicle mass, in the case of conventional lead-acid technology. Both have lower energy and power density than petroleum fuels. However, recent advances in battery efficiency, capacity, materials, safety, toxicity and durability are likely to allow their superior characteristics to be widely applied in car-sized EVs,
For especially large electric vehicles, such as submarines and aircraft carriers, the chemical energy of the diesel-electric can be replaced by a nuclear reactor. The nuclear reactor usually provides heat, which drives a steam turbine, which drives a generator, which is then fed to the propulsion. This energy produces nuclear waste.

6/18/2007

History of the electric vehicle


Citroen Berlingo Electrique vans of the ELCIDIS goods distribution service in La Rochelle,France

BEVs were among some of the earliest automobiles — electric vehicles predate gasoline and diesel. Between 1832 and 1839 (the exact year is uncertain), Scottish businessman Robert Anderson invented the first crude electric carriage. Professor Sibrandus Stratingh of Groningen, the Netherlands, designed the small-scale electric car, built by his assistant Christopher Becker in 1835.


The Canadian Dynasty EV 4 door sedan neighborhood eletric vehicle

The improvement of the storage battery, by Frenchmen Gaston Plante in 1865 and Camille Faure in 1881, paved the way for electric vehicles to flourish. France and Great Britain were the first nations to support the widespread development of electric vehicles.
Just prior to 1900, before the pre-eminence of powerful but polluting internal combustion engines, electric automobiles held many speed and distance records. Among the most notable of these records was the breaking of the 100 km/h (60 mph) speed barrier, by Camille Jenatzy on April 29, 1899 in his 'rocket-shaped' vehicle Jamais Contente, which reached a top speed of 105.88 km/h (65.79 mph).

BEVs, produced by Anthony Electric, Baker, Detroit, Edison, Studebaker, and others during the early 20th Century for a time out-sold gasoline-powered vehicles. Due to technological limitations and the lack of transistor-based electric technology, the top speed of these early electric vehicles was limited to about 32 km/h (20 mph). These vehicles were successfully sold as town cars to upper-class customers and were often marketed as suitable vehicles for women drivers due to their clean, quiet and easy operation. Electrics did not require hand-cranking to start.

The introduction of the electric starter by Cadillac in 1913 simplified the task of starting the internal combustion engine, formerly difficult and sometimes dangerous. This innovation contributed to the downfall of the electric vehicle, as did the mass-produced and relatively inexpensive Ford Model-T, which had been produced for four years, since 1908.[4] Internal-combustion vehicles advanced technologically, ultimately becoming more practical than — and out-performed — their electric-powered competitors.

Electric Micro-vans produced by Micro-Vett on the basis off a Piaggio(rebranded Isuzu) vehicle exchanging the internal combustion engine for distribution services in Rome,Italy courtesy greenfleet.info

Another blow to BEVs was the loss of Edison's direct current (DC) electric power transmission system in the War of Currents. This deprived BEV users of a convenient source of DC electricity to recharge their batteries. As the technology of rectifiers was still in its infancy, changing alternating current to DC required a costly rotary converter.
Battery electric vehicles became popular for some limited range applications. Forklifts were BEVs when they were introduced in 1923 by Yale and some battery electric fork lifts are still produced. BEV golf carts have been available for many years, including early models by Lektra in 1954. Their popularity led to their use as neighborhood electric vehicles and expanded versions became available which were partially "street legal".

By the late 1930s, the electric automobile industry had completely disappeared, with battery-electric traction being limited to niche applications, such as certain industrial vehicles.
The 1947 invention of the point-contact transistor marked the beginning of a new era for BEV technology. Within a decade, Henney Coachworks had joined forces with National Union Electric Company, the makers of Exide batteries, to produce the first modern electric car based on transistor technology, the Henney Kilowatt, produced in 36-volt and 72-volt configurations. The 72-volt models had a top speed approaching 96 km/h (60 mph) and could travel nearly an hour on a single charge. Despite the improved practicality of the Henney Kilowatt over previous electric cars, it was too expensive, and production was terminated in 1961. Even though the Henney Kilowatt never reached mass production volume, their transistor-based electric technology paved the way for modern EVs.
After California indicated that it would kill its ZEV Mandate, Toyota offered the last 328 RAV4-EV for sale to the general public during six months (ending on Nov. 22, 2002). All the rest were only leased, and with minor exceptions those models were withdrawn from the market and destroyed by manufacturers (other than Toyota). Toyota not only supports the 328 Toyota RAV4-EV in the hands of the general public, still all running at this date, but also supports hundreds in fleet usage. From time to time, Toyota RAV4-EV come up for sale on the used market, at prices that have ranged up to the mid 60 thousands of dollars. These are highly prized by solar homeowners who wish to charge their cars from their solar electric rooftop systems.
As of July, 2006, there are between 60,000 and 76,000 low-speed, battery powered vehicles in use in the US, up from about 56,000 in 2004 according to Electric Drive Transportation Association estimates


Battery electric vehicle



The Toyota RAV4 EV was powered by
twenty-four 12 volt batteries,with an
operational cost equivalent of over
165 miles per gallon at 2005 US
gasoline prices.





Camille Jenatzy in electric car La Jamais
Contente,1899

A battery electric vehicle (BEV) is an electric vehicle that utilizes chemical energy stored in rechargeable battery packs. Electric vehicles use electric motors and motor controllers instead of internal combustion engines (ICEs). Vehicles using both electric motors and ICEs are examples of hybrid vehicles, and are not considered pure BEVs because they operate in a charge-sustaining mode. Hybrid vehicles with batteries that can be charged externally to displace some or all of their ICE power and gasoline fuel are called plug-in hybrid electric vehicles (PHEV), and are pure BEVs during their charge-depleting mode. BEVs are usually automobiles, light trucks, neighborhood electric vehicles, motorcycles, motorized bicycles, electric scooters, golf carts, forklifts and similar vehicles, because batteries are less appropriate for larger long-range applications.
BEVs were among the earliest automobiles, and are more energy-efficient than internal combustion, fuel cell, and most other types of vehicles. BEVs produce no exhaust fumes, and minimal pollution if charged from most forms of renewable energy. Many are capable of acceleration exceeding that of conventional vehicles, are quiet, and do not produce noxious fumes. BEVs reduce dependence on petroleum, thus enhancing national security, and mitigate global warming by alleviating the greenhouse effect.
Historically, BEVs and PHEVs have had issues with high battery costs, limited travel distance between battery recharging, charging time, and battery lifespan, which have limited widespread adoption. Ongoing battery technology advancements have addressed many of these problems; many models have recently been prototyped, and a handful of future production models have been announced. Toyota, Honda, Ford and General Motors all produced BEVs in the 90s in order to comply with the California Air Resources Board's Zero Emission Vehicle Mandate, which was later defeated by the manufacturers and the federal government. The major US automobile manufacturers have been accused of deliberately sabotaging their electric vehicle production efforts.

6/12/2007

Internal combustion engine


The internal combustion engine is an engine in which the combustion, or rapid oxidation, of gas and air occurs in a confined space called a combustion chamber. This exothermic reaction of a fuel with an oxidizer creates gases of high temperature and pressure, which are permitted to expand. The defining feature of an internal combustion engine is that useful work is performed by the expanding hot gases acting directly to cause pressure, further causing movement of the piston inside the cylinder. For example by acting on pistons, rotors, or even by pressing on and moving the entire engine itself.

A colorized automobile engine

This contrasts with external combustion engines, such as steam engines and Stirling engines, which use an external combustion chamber to heat a separate working fluid, which then in turn does work, for example by moving a piston.
The term Internal Combustion Engine (ICE) is almost always used to refer specifically to reciprocating engines, Wankel engines and similar designs in which combustion is intermittent. However, continuous combustion engines, such as jet engines, most rockets and many gas turbines are also internal combustion engines.

History

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.

17th century: English inventor Sir Samuel Morland used gunpowder to drive water pumps.

1780's: Alessandro Volta built a toy electric pistol 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.

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.

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.

6/07/2007

Safety


Road traffic injuries represent about 25% of worldwide injury-related deaths (the leading cause) with an estimated 1.2 million deaths (2004) each year.
Result of a serious automobile accident.


Automobile accidents are almost as old as automobiles themselves. Early examples include Mary Ward, who became one of the first document automobile fatalities in 1869 in Parsonstown, Ireland, and Henry Bliss, one of the United State's first pedestrian automobile casualties in 1899 in New York.

Cars have many basic safety problems - for example, they have human drivers who make mistakes, wheels that lose traction when the braking or turning forces are too high. Some vehicles have a high center of gravity and therefore an increased tendency to roll over. When driven at high speeds, collisions can have serious or even fatal consequence.

Early safety research focused on increasing the reliability of brakes and reducing the flammability of fuel systems. For example, modern engine compartments are open at the bottom so that fuel vapors, which are heavier than air, vent to the open air. Brakes are hydraulic and dual circuit so that failures are slow leaks, rather than abrupt cable breaks. Systematic research on crash safety started[citation needed] in 1958 at Ford Motor Company. Since then, most research has focused on absorbing external crash energy with crushable panels and reducing the motion of human bodies in the passenger compartment. This is reflected in most cars produced today.

Airbags,a modern component of automobile safety

Significant reductions in death and injury have come from the addition of Safety belts and laws in many countries to require vehicle occupants to wear them. Airbags, a modern component of automobile safetySignificant reductions in death and injury have come from the addition of Safety belts and laws in many countries to require vehicle occupants to wear them. Airbags and specialised child restraint systems have improved on that. Structural changes such as side-impact protection bars in the doors and side panels of the car mitigate the effect of impacts to the side of the vehicle. Many cars now include radar or sonar detectors mounted to the rear of the car to warn the driver if he or she is about to reverse into an obstacle or a pedestrian. Some vehicle manufacturers are producing cars with devices that also measure the proximity to obstacles and other vehicles in front of the car and are using these to apply the brakes when a collision is inevitable. There have also been limited efforts to use heads up displays and thermal imaging technologies similar to those used in military aircraft to provide the driver with a better view of the road at night.

There are standard tests for safety in new automobiles, like the EuroNCAP and the US NCAP tests. There are also tests run by organizations such as IIHS and backed by the insurance industry.

Despite technological advances, there is still significant loss of life from car accidents: About 40,000 people die every year in the United States, with similar figures in European nations. This figure increases annually in step with rising population and increasing travel if no measures are taken, but the rate per capita and per mile traveled decreases steadily. The death toll is expected to nearly double worldwide by 2020. A much higher number of accidents result in injury or permanent disability. The highest accident figures are reported in China and India. The European Union has a rigid program to cut the death toll in half by 2010, and member states have started implementing measures.

Automated control has been seriously proposed and successfully prototyped. Shoulder-belted passengers could tolerate a 32 g emergency stop (reducing the safe inter-vehicle gap 64-fold) if high-speed roads incorporated a steel rail for emergency braking. Both safety modifications of the roadway are thought to be too expensive by most funding authorities, although these modifications could dramatically increase the number of vehicles able to safely use a high-speed highway. This makes clear the often-ignored fact road design and traffic control also play a part in car wrecks; unclear traffic signs, inadequate signal light placing, and poor planning (curved bridge approaches which become icy in winter, for example), also contribute.

Fuel and propulsion technologies


The Henney Kilowatt,the first modern (transistor-controlled) electric car.

Most automobiles in use today are propelled by gasoline (also known as petrol) or diesel internal combustion engines, which are known to cause air pollution and are also blamed for contributing to climate change and global warming. Increasing costs of oil-based fuels and tightening environmental laws and restrictions on greenhouse gas emissions are propelling work on alternative power systems for automobiles. Efforts to improve or replace these technologies include hybrid vehicles, electric vehicles and hydrogen vehicles.

Diesel
Diesel engined cars have long been popular in Europe with the first models being introduced in the 1930s by Mercedes Benz and Citroen. The main benefit of Diesels are a 50% fuel burn efficiency compared with 27% in the best gasoline engines. A down side of the diesel is the presence in the exhaust gases of fine soot particulates and manufacturers are now starting to fit filters to remove these. Many diesel powered cars can also run with little or no modifications on 100% biodiesel.

2007 Tesia Roadster
Gasoline
Gasoline engines have the advantage over diesel in being lighter and able to work at higher rotational speeds and they are the usual choice for fitting in high performance sports cars. Continuous development of gasoline engines for over a hundred years has produced improvements in efficiency and reduced pollution. The carburetor was used on nearly all road car engines until the 1980s but it was long realised better control of the fuel/air mixture could be achieved with fuel injection. Indirect fuel injection was first used in aircraft engines from 1909, in racing car engines from the 1930s, and road cars from the late 1950s. Gasoline Direct Injection (GDI) is now starting to appear in production vehicles such as the 2007 BMW MINI. Exhaust gases are also cleaned up by fitting a catalytic converter into the exhaust system. Clean air legislation in many of the car industries most important markets has made both catalysts and fuel injection virtually universal fittings. Most modern gasoline engines are also capable of running with up to 15% ethanol mixed into the gasoline - older vehicles may have seals and hoses that can be harmed by ethanol. With a small amount of redesign, gasoline-powered vehicles can run on ethanol concentrations as high as 85%. 100% ethanol is used in some parts of the world (such as Brazil), but vehicles must be started on pure gasoline and switched over to ethanol once the engine is running. Most gasoline engined cars can also run on LPG with the addition of an LPG tank for fuel storage and carburetion modifications to add an LPG mixer. LPG produces fewer toxic emissions and is a popular fuel for fork lift trucks that have to operate inside buildings.
Electric
The first electric cars were built in the late 1800s, but the building of battery powered vehicles that could rival internal combustion models had to wait for the introduction of modern semiconductor controls. Because they can deliver a high torque at low revolutions electric cars do not require such a complex drive train and transmission as internal combustion powered cars. Some are able to accelerate from 0-60 mph (96 km/hour) in 4.0 seconds with a top speed around 130 mph (210 km/h). They have a range of 250 miles (400 km) on the EPA highway cycle requiring 3-1/2 hours to completely charge. Equivalent fuel efficiency to internal combustion is not well defined but some press reports give it at around 135 mpg.
Steam
Steam power, usually using an oil or gas heated boiler, was also in use until the 1930s but had the major disadvantage of being unable to power the car until boiler pressure was available. It has the advantage of being able to produce very low emissions as the combustion process can be carefully controlled. Its disadvantages include poor heat efficiency and extensive requirements for electric auxiliaries

Gas turbine
In the 1950s there was a brief interest in using gas turbine (jet) engines and several makers including Rover produced prototypes. In spite of the power units being very compact, high fuel consumption, severe delay in throttle response, and lack of engine braking meant no cars reached production.

Rotary (Wankel) engines
Rotary Wankel engines were introduced into road cars by NSU with the Ro 80 and later were seen in several Mazda models. In spite of their impressive smoothness, poor reliability and fuel economy led to them largely disappearing. Mazda, however, has continued research on these engines and overcame most of the earlier problems.

Future developments
Much current research and development is centered on hybrid vehicles that use both electric power and internal combustion. Research into alternative forms of power also focus on developing fuel cells, Homogeneous Charge Compression Ignition (HCCI), stirling engines and even using the stored energy of compressed air or liquid nitrogen

Design

The design of modern cars is typically handled by a large team of designers and engineers from many different disciplines. As part of the product development effort the team of designers will work closely with teams of design engineers responsible for all aspects of the vehicle. These engineering teams include: chassis, body and trim, powertrain, electrical and production.
The 1955 Citroen DS;revolutionary visual design and technological innovation.

The design team under the leadership of the design director will typically comprise of an exterior designer, an interior designer (usually referred to as stylists), and a color and materials designer. A few other designers will be involved in detail design of both exterior and interior. For example, a designer might be tasked with designing the rear light clusters or the steering wheel. The color and materials designer will work closely with the exterior and interior designers in developing exterior color paints, interior colors, fabrics, leathers, carpet, wood trim, and so on.
In 1924 the American national automobile market began reaching saturation. To maintain unit sales, General Motors instituted annual model-year design changes (also credited to Alfred Sloan) in order to convince car owners they needed a replacement each year. Since 1935 automotive form has been driven more by consumer expectations than engineering improvement.
There have been many efforts to innovate automobile design funded by the NHTSA, including the work of the NavLab group at Carnegie Mellon University. Recent efforts include the highly publicized DARPA Grand Challenge race.
Acceleration, braking, and measures of turning or agility vary widely between different makes and models of automobile. The automotive publication industry has developed around these performance measures as a way to quantify and qualify the characteristics of a particular vehicle. See quarter mile and 0 to 60 mph.

History of Car

History



Some sources suggest Ferdinand Verbiest, whilst a member of a Jesuit mission in China, may have built the first steam powered car around 1672. Fran?ois Isaac de Rivaz, a Swiss inventor, designed the first internal combustion engine which was fuelled by a mixture of hydrogen and oxygen and used it to develop the world's first vehicle to run on such an engine. The design was not very successful, as was the case with Samuel Brown, Samuel Morey, and Etienne Lenoir who each produced vehicles powered by clumsy internal combustion engines.
An automobile powered by an Otto gasoline engine was built in Germany by Karl Benz in 1885 and granted a patent in the following year. Although several other engineers
(including Gottlieb Daimler, Wilhelm Maybach and Siegfried Marcus)
Karl Benz
were working on the problem at about the same time, Benz is generally credited with the invention of the modern automobile.
Approximately 25 of Benz's vehicles were built before 1893, when his first four-wheeler was introduced. They were powered with four-stroke engines of his own design. Emile Roger of France, already producing Benz engines under license, now added the Benz automobile to his line of products. Because France was more open to the early automobiles, more were built and sold in France through Roger than Benz sold in Germany. From 1890 to 1895 about 30 vehicles were built by Daimler and his assistant, Maybach, either at the Daimler works or in the Hotel Hermann, where they set up shop after falling out with their backers. Benz and Daimler seem to have been unaware of each other's early work and worked independently.

Karl Benz's"Velo"model(1894)
-entered into the first automobile race

In 1890, Emile Levassor and Armand Peugeot of France began producing vehicles with Daimler engines, and so laid the foundation of the motor industry in France. The first American car with a gasoline internal combustion engine supposedly was designed in 1877 by George Selden of Rochester, New York, who applied for a patent on an automobile in 1879. In Britain there had been several attempts to build steam cars with varying degrees of success with Thomas Rickett even attempting a production run in 1860. Santler from Malvern is recognized by the Veteran Car Club of Great Britain as having made the first petrol-powered car in the country in 1894 followed by Frederick William Lanchester in 1895 but these were both one-offs. The first production vehicles came from the Daimler Motor Company, founded by Harry J. Lawson in 1896, and making their first cars in 1897.


In 1892, Rudolf Diesel got a patent for a "New Rational Combustion Engine". In 1897 he built the first Diesel Engine. In 1895, Selden was granted a United States patent(U.S. Patent 549,160 ) for a two-stroke automobile engine, which hinderd more than encouraged development of autos in the United States. Steam, electric, and gasoline powered autos competed for decades, with gasoline internal combustion engines achieving dominance in the 1910s.



Ford Model T,1927,regarded as
the first affordable automobile

The large-scale, production-line manufacturing of affordable automobiles was debuted by Ransom Olds at his Oldsmobile factory in 1902. This assembly line concept was then greatly expanded by Henry Ford in the 1910s. Development of automotive technology was rapid, due in part to the hundreds of small manufacturers competing to gain the world's attention. Key developments included electric ignition and the electric self-starter (both by Charles Kettering, for the Cadillac Motor Company in 1910-1911), independent suspension, and four-wheel brakes.
Although various pistonless rotary engine designs have attempted to compete with the conventional piston and crankshaft design, only Mazda's version of the Wankel engine has had more than very limited success.
Since the 1920s, nearly all cars have been mass-produced to meet market needs, so marketing plans have often heavily influenced automobile design. It was Alfred P. Sloan who established the idea of different makes of cars produced by one company, so buyers could "move up" as their fortunes improved. The makes shared parts with one another so larger production volume resulted in lower costs for each price range. For example, in the 1950s, Chevrolet shared hood, doors, roof, and windows with Pontiac; the LaSalle of the 1930s, sold by Cadillac, used cheaper mechanical parts made by the Oldsmobile division.