Spark-ignition engine Trends

In the face of growing competition from diesels and alternative power sources, some of the latest prototype and production gasoline-fueled engines show how continued engineering development is meeting demands for more power, reduced fuel consumption and emissions, and more efficient packaging.

Considerable progress has been made in development of the internal combustion engine over its more than 100-year history, particularly in recent years. Examples include the adaptation of spark-ignition (SI) engines to three-way catalysts and the introduction of direct injection in diesel engines. However, even greater demands range from more stringent emissions legislation, manufacturers' commitments to reduce C02 emissions, and customer requests for higher performance and greater comfort without prejudice to safety.

European limits on hazardous emissions were reduced in 2000 and will be tightened in 2005. Limits for 2005 on HC, NO2, and particulates will be one-fifth of today's levels, and new test cycles with no warm-up period will be mandated. In the U.S., legislation will demand ultra-low-emission vehicles (ULEV) and, from 2003 onward, California will require a greater mix of zero or near-zero-emissions vehicles.

Greenhouse effect concerns have led most European car manufacturers to commit to introducing cars that, on average, emit less than 140 g/km (225g/mi) C02 by 2008. This corresponds to a reduction of more than 25% in fuel consumption compared with 1990.

Customers will require even greater safety and comfort that, in most cases, can only be fulfilled with higher vehicle mass, which conflicts with demands for less energy consumption. In addition, vehicle performance must be maintained, and the costs of ownership cannot rise.

The main target for advanced spark-ignition engine development is improvement in fuel economy, thus a reduction in C02 emissions. Technical solutions include supercharging and turbocharging, fully variable-valve timing, and direct injection.

 

THE DIESEL ENGINE

In 1890s Rudolf Diesel, a German, invented the engine that bears his name. As distinguished from gasoline engines diesels have no ignition system fed with electricity. The fuel is ignited simply by contact with very hot air in the cylinder

The operation performed is like this: when taken in the cylinder the air is highly compressed, the temperature rises so the heated fuel-air mixture burns. The higher the pressure, the higher the temperature. Besides the compressed mixture produced more power than that uncompressed.

Diesel engines power many of the used vehicles and other equipment. They are usually used in cases where engine weight is not a prime factor. Their advantage is that they are simple in design and use much heavier liquid fuels than gasoline engines. The cost of a heavier fuel is much less than that of a light one.

Besides the fuel consumption of a diesel is much less than that of gasoline engines.

Although applied for many purposes diesel engines have certain disadvantages. Their weight is more than that of a gasoline engine of the same power and it occupies much space. The disadvantages of diesels as passenger-car engines are slow performance, noise and smoke.

All the companies investigating diesels are trying to reduce noise and smoke, but the problems are not yet entirely solved. Diesel engines clatter when started on a cold morning. And the warm-up period for all diesels seems too long to drivers accustomed to gasoline models.

 

 

HOW GM’s HY-WIRE WORKS

Cars are very complicated machines with an incredibly simple job of turning wheels. The overall function of the car being so basic, does it actually need all those complex heavy devices? Most likely, a lot of us will be driving radically different vehicles within 20 years.

Two basic elements dictating car design are the internal combustion engine and mechanical and hydraulic linkages. The defining feature of the Hi-wire is that it has neither of them. The engine is replaced with a fuel cell stack, which powers an electric motor connected to the wheels. A computer-based drive-by-wire system substitutes the linkages.

These changes result in a very different car – and a very different driving. These are no pedals, no steering wheel and no engine compartment. In fact, all the equipment moving the car is housed in an 11-inch-thick aluminum chassis at the base of the car. The main computer in the chassis sends electronic signals to the motor control unit to vary the speed, the steering mechanism to maneuver the car, and the braking system to slow the car down.

Everything above the chassis serves only to driver control and passenger comfort, but the coolest thing in this design is the possibility to switch from a van to a sports car just by replacing the car body.

The driver’s control unit (X-drive) looks like a video game joystick having two ergonomic grips, to the left and right of a small monitor replacing an instrument panel and giving you a rear view from video cameras (in place of mirrors). Buttons on the controller let you switch easily from neutral to drive to reverse, and a starter button turns the car on. As it doesn’t directly drive any part of the car, the X-drive controller can be moved freely in the passenger compartment. A second monitor provides stereo, climate control and navigation information.

There are no ideal cars as yet. Safety is a big concern with drive-by-wire cars since electrical failure means the total loss of control. The other burning issue is developing energy-efficient methods of supplying hydrogen for the onboard fuel-cell stacks. Assuming that GM can tackle the major fuel and safety issues satisfactorily, the highway will see some major changes within the next few decades.

 

 

ZERO-POLLUTION CARS

The electric car is an environmentally friendly alternative to gasoline-powered vehicles. It performs like a conventional car with one important difference – it is nearly silent and pollution-free. The electric car is propelled by an electric motor powered from a controller, which in its turn gets its power from rechargeable batteries. However, the batteries need replacement every 20,000 miles. Fuel cells solve the battery problem.

A fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into water, producing electricity and heat in the process. Unlike a battery, you can continually recharge a fuel cell by adding chemical fuel – hydrogen from an onboard storage tank and oxygen from the atmosphere. The proton exchange membrane fuel cell (PEMFC) seems to be one of the most promising technologies. A single fuel cell produces about 0.7 volts. To get this voltage up many separate fuel cells are combined to form a fuel cell stack.

Zero-pollution cars are also designed to run on compressed air using the concept of the steam engine. Liquid nitrogen stored at -320F serves as the propellant for the LN 2000’s cryogenic engine. Air moving around the vehicle heats the liquid nitrogen to the boiling temperature and causes it to turn to gas pushing on the engine’s pistons. The only emission being nitrogen (which makes up 78% of the atmosphere), the air-compressed car fully justifies the name of its manufacturer – Zero-pollution Motors.

 

 

FLYING CARS

Just a decade and a half after the Wright Brothers took off in their airplane over the plains of Kitty Hawk, N.C., in 1903, other pioneering men started dreaming of a flying car. The attempt to develop a gliding horse cart in the 18^th century, to no great surprise, failed. Numerous flying cars are being invented today. Moller’s latest project, the Skycar M400, is designed to take off and land vertically, like a Harrier Jet, in small spaces. Having a range of 900 miles, it will cruise at around 350 mph with the top speed of 400 mph using petrol, diesel, alcohol, kerosene and propane as fuel. The fuel mileage of the Skycar will be comparable to that of a medium-sized car, getting 20 miles to the gallon. To make the Skycar safe and available to public, it will be completely controlled by computers using the Global Positioning System (GPS) satellites – a so-called ‘fly-by-wire system’. In an emergency the vehicle will release a parachute and airbags, internally and externally, to cushion the impact of the crash. The cost of a Skycar is estimared to be $60,000 if mass-produced.

MACRO Industries’ SkyRider X2R will use the same fly-by-wire system to safely transport passengers. Drivers will simply get in, turn on the power and enter the address or phone number of the desired destination, with the SkyRider doing the rest. MACRO said that the system wuld be fully automatic, but allowing some manual control. Commands will be entered just by telling the car what you want it to do.

Similarly to Skycars and SkyRiders, CityHawks also take off and land vertically. However, there are some key differences. The CityHawk will be powered by fans driven by four internal combustion engines. This number of engines will allow the vehicle to land even if one of the engines is lost. The CityHawk will have cruising speed of 90-100 mph. The car is likely to be used as an air taxi, for news gathering and for traffic control.

The mass availability of flying cars can be very scary. Yet, if proper safeguards observed, flying cars will not only cut rush hours and traffic jams, but also they will allow us to live hundreds of miles farther from work and still make it to the office in no time.

BENTLEY. THE NEW GENERATION

The new Bentley TURBO R. British elegance that confirms the immense power waiting to be released. The most refined automotive technology. The world's finest sporting car, sleek and streamlined, safe and quiet, comfortable and elegant and yet so powerful. Delivering the most exiting driving experience in luxurious surroundings.

The new proportions of the classic radiator shell combined with a restyled air dam to streamline the front, while the integrated bumpers and color coded sills continue the smooth line around to the rear balance.

By adding new and larger 17-inch road wheels with specially designed directional tires TURBO R gains a noticeable improvement in performance and responsiveness. While Brooklyn's with its new 16-inch road wheels and low profile tires enjoy improved handling, performance and above all comfort.

Ever since the 1920s when W.O. Bentley first produced a series of motor cars which swept the board of Le Mans, the Bentley marque has stood for engineering innovation, always striving to provide their owners with the maximum driving pleasure. The mighty 6.75 liter V8 Bentley engine delivers real exhilaration.

Still assembled by hand to tolerances of tenth thousandth of an inch, these finely balanced engines harness the most advanced electronic management and control systems.

The new adaptive shift control system for turnover arms changes the transmission panel to the style of driving and allows a maximum extraction of Bentley power and sporting exhilaration.

To enjoy such performance in luxurious surroundings is the unique Bentley experience and the subtlest cockpit now sports some thoughtful innovations. A tilt adjustable steering wheel swings up to allow easy entry and exit when the door is opened or the key removed from the ignition.

The new center console and the fascia layout present the driver with absolute control. A new center armrest now houses the CD multichanger as well as the telephone. New veneer panels reveal the new in-car entertainment controls. The new center console also provides independent air conditioning to the rear compartment. A new seat design has improved comfort and support, while providing increased head room.

So many Bentley engineering advances have contributed to safer driving throughout the history of motoring. Safety derived through immense power and reserve for safer overtaking. Side impact protection bars pioneered by the company in 1981. Antilock braking systems perfectly suit the Bentley's high performance.

The most sensitive adaptive ride control that monitors the acceleration, braking and cornering style every one hundredth of a second to ensure the car is kept stable and responsive. Full-sized driver and passenger airbags are neatly housed in the immaculate interior. The driver information panel is still one of the most sophisticated such instrument outside the world of aviation.

And the dual level air conditioning system designed to maintain driver alertness and concentration through carefully balanced temperature controls, allowing cooler air to flow at head level, with warmer stream soothing the feet as they rest on Wilton carpets and lamb wool rugs. The commanding driving position supported by the new economically designed seats gives the Bentley's driver the safest control. This combination of safety and powerful elegance, this fusion of thrusting exhilaration with traditional luxury is the very latest development in the pursuit of Bentley's sporting excellence. To own the new Bentley is to appreciate the ultimate driving experience.