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Continuously Variable Transmissions

Continuously Variable Transmissions, or CVT's, as they are called in the trade, are used in snowmobiles, some all terrain vehicles (ATV's), and a few automobiles. A continuously variable transmission works just like it sounds. It continuously varies the gear ratios between the engine and the final drive. There is no need to select different gears: just place the shifter in forward and away you go.

Why use a CVT rather than a conventional automatic or manual transmission? The answer is efficiency; engine efficiency. With a CVT, the engine goes from an idle to a pre-programmed rpm immediately so the engine input is constant, and the transmission varies the output speed for smooth, seamless acceleration. Keeping the engine at a constant rpm allows the engineers to optimise ignition timing, camshaft design, and manifold tuning for excellent volumetric efficiency and low emissions.

Other reasons for using CVT's include simplicity of design, and smooth power application to the ground. The simplicity part comes by using fewer parts. Vehicles with reverse gear obviously have more parts than a simple forward drive, but there are still fewer parts and gears to manufacture.

The smooth power application of CVT's is useful in off-road vehicles. Power can be applied without any jerks or surges that could cause the vehicle to lose traction on steep climbs or loose terrain.

So how do they work? The two most common systems use a belt or a chain. Let's look at snowmobiles first. They use a belt. On a snowmobile there are two pulleys connected by a rubber drive belt. Both pulleys are "V" shaped and the width of the "V" can be varied. The drive pulley is connected to the engine and the width of the pulley is controlled by engine speed. At idle, the pulley is wide and the belt is not gripped. Push on the throttle, and the governor causes the pulley sides to move together. When engine speed reaches it's maximum, the pulley continues to become narrower as vehicle speed increases, causing the drive belt to climb up and keeping the engine at its peak power.

The driven pulley also varies its width, but its main job is to keep the slack out of the belt. The driven pulley halves are spring loaded to force them together, and as the drive pulley closes up, the belt climbs up the drive pulley causing the belt to tighten, forcing the driven pulley apart. The variable width of the pulleys and the variable distance of the belt from the centre of the pulleys provide the continuously variable drive.

Automobiles with CVT's use a drive chain instead of a rubber belt. The chain is stronger and more durable on a much heavier vehicle. Although much more complex, automotive CVT's use variable width pulleys just like snowmobiles. Hydraulics and computer controls are used to vary the width of the drive pulley.

Michael Schumacher

Michael Schumacher ( born 3 January 1969) is a retired German Formula One racing driver. Schumacher is a seven-time World Champion and is widely regarded as one of the greatest F1 drivers of all time.He holds many of Formula One's driver records, including most championships, race victories, fastest laps, pole positions, points scored and most races won in a single season – 13 in 2004. In 2002 he became the only driver in Formula One history to finish in the top three in every race of a season and then also broke the record for most consecutive podium finishes. According to the official Formula One website he is "statistically the greatest driver the sport has ever seen".

After beginning with karting, Schumacher won German drivers' championships in Formula König and Formula Three before joining Mercedes in the World Sportscar Championship. After one Mercedes-funded race for the Jordan Formula One team, Schumacher signed as a driver for the Benetton Formula One team in 1991. After winning consecutive championships with Benetton in 1994/5, Schumacher moved to Ferrari in 1996 and won another five consecutive drivers' titles with them from 2000 to 2004. Schumacher retired from Formula One driving in 2006 staying with Ferrari as an advisor. Schumacher agreed to return for Ferrari part-way through 2009, as cover for the badly injured Felipe Massa, but was prevented by a neck injury. He later signed a three-year contract to drive for the new Mercedes GP team starting in 2010.

His career has not been without controversy, including being twice involved in collisions in the final race of a season that determined the outcome of the world championship, with Damon Hill in 1994 in Adelaide, and with Jacques Villeneuve in 1997 in Jerez. Off the track Schumacher is an ambassador for UNESCO and a spokesman for driver safety. He has been involved in numerous humanitarian efforts throughout his life and donated tens of millions of dollars to charity.[11] Michael and his younger brother Ralf Schumacher are the only brothers to win races in Formula One, and they were the first brothers to finish 1st and 2nd in the same race, in Montreal in 2001. The two brothers repeated this achievement in four more races (the 2001 French Grand Prix, the 2002 Brazilian Grand Prix, the 2003 Canadian Grand Prix and the 2004 Japanese Grand Prix).

Lockers Explained

When you think of traction control on your Jeep, most likely the first thing that comes to your mind is the tires. While tires are an essential part of good traction off road, most of us don’t seem to remember that it’s the differential that controls just how much power our tires are going to receive. In most cases, an open differential makes it extremely hard to gain the necessary traction you need on the trail, no matter how awesome your tires. Now, how do we fix that problem? The answer: Lockers.
Lockers provide you with much more control over the power distribution to your tires, both on and off the road. The type of locker you install will determine the extent of control you have over the locker or whether or not the locker automatically engages itself. This article is meant to give you an idea of the most popular types of lockers available for your Jeep.

Let’s begin with a quick explanation of what lockers do. Simply put, a locker is a device that controls power distribution to your tires and control how power is redistributed to the tires in different situations, such as changing terrain and tire spin. Housed in the differential case, lockers come in two options, Selectable and Automatic. We’ll divide these into two sections for simplicity’s sake:

Selectable Lockers: These types of lockers allow the driver to control when the locker is engaged and when it disengages, hence the name “Selectable”. These lockers are controlled either pneumatically by an air compressor, or electronically by the use of magnetically charged currents.

Animation of ARB Air Locker courtesy of www.arbusa.com

Air-actuated Selectable Lockers: Air actuated lockers are usually controlled by a switch mounted on the dash. The switch controls an air solenoid that in turn sends pressurized air down a pneumatic air line to the axle housing and into the air locker in the differential. The compressed air actuates the piston and clutch gear, moving the gear into the “locked” position. The side gear is locked to the housing providing 100% traction lock-up between the two axle shafts.
The locker is deactivated by a flip of the switch, forcing the solenoid to release the air pressure. In turn the piston springs return to the pistons and the clutch gear returns to its original open position. The best example is an ARB Locker like the one in the animation to the right.

The benefits of Air Actuated Selectable Lockers:

100% traction on demand without driveline wear
Easy to install, operate, and maintain
Simple design with minimal moving parts, making it ultra-durable
No extra tire wear
Option to disengage in places that an automatic locker could not such as hill-sides or rocky areas where an open diff would perform much better than a locked one.

The disadvantages of Air Actuated Selectable Lockers:

High initial cost
Must have an air compressor
Require air hoses and fluid to work

Electronic Selectable Lockers:Electronic Lockers operate very similarly to their air counterparts, with the exception that instead of using compressed air they use electromagnetic pulses to engage and disengage the locker mechanism. These electronic signals are also controlled by a switch that the driver can easily control. An example would be an Eaton ELocker.

The benefits of Electronic Selectable Lockers:

No compressor noise
100% traction on demand without driveline wear
Easy to install, operate, and maintain
No extra tire wear
Can disengage in places that automatic lockers would self-engage, such as hill-sides or rocky areas where an open differential would perform much better than a locked one.

The disadvantages of Electronic Selectable Lockers:

High initial cost
More moving parts
Requires electricity to operate

Oxlocker: Functions the same as an Electronic locker, except using cabling to control the locking mechanism instead of electronics.

The benefits of an Oxlocker:

Does not require electricity or air to operate
Less costly

The Disadvantages of an Oxlocker:

Cheaper material
Cable malfunctioning, or getting caught on something

Automatic Lockers: This type of locking system is not user controlled; rather, it is controlled by certain conditions such as speed, torque, and tire spin. There are several different types of automatic lockers, which vary in cost and usability.

Torque Actuated: A torque actuated locker is automatically controlled by the amount of twisting force exerted on the differential. This type of automatic locker is essentially always engaged, as the driver has no direct control over the components. The locker can sense turns and it will disengage itself when going around corners, as long as you aren’t giving it gas, allowing the wheels to spin at different speeds to properly turn the vehicle. Examples include Eaton’s Detroit series Locking Differentials.

Gleason-Torsen: Similar to a Detroit Trutrac. Was more popular 15-20 years ago but they aren’t seen anymore.

The benefits of Torque Actuated Automatic Lockers:

Never have to worry about when to engage your locker.
No extra components such as switches or air lines are required.
This is the only automatic locker that can work when one tire is completely off the ground.

The disadvantages of Torque Actuated Automatic Lockers:

Almost always engaged
No way to control, completely automated
Increased tire wear

Limited Slip: Limited slip lockers are a good bridge between your standard differential and a full locking diff. These lockers are not capable of 100% full lockup; however they provide a lot better traction when off-roading than an open carrier.

The benefits of a Limited Slip Automatic Locker:

More cost-efficient to manufacture
Never have to worry about engaging it
More forgiving on the street than a Torque Actuated Locker

The disadvantages of a Limited Slip Automatic Locker:

Do not provide 100% lock-up
Requires special oil friction modifier

Spools: Spools are the simplest way to lock your differential. Simply put, a spool is a solid carrier that allows for no wheel speed differentiation. Spools are always engaged. This type of locker is usually seen in competition and drag racing.

The benefits of Spools:

Extremely cheap
Permanently locked
Allows no change in wheel speed differentiation

The disadvantages of Spools:

Tire wear
Low turning radius
Additional stress applied to shafts

Mini-spools: Mini spools replace the spider gears in an open differential into a full non-differentiating diff that locks both shafts together. This would make it just as strong as the stock carrier is.

The benefits of a Mini-Spool:

Most cost-effecient locker available
Can use the same stock carrier

The disadvantages of a Mini-Spool:

Like all other automatic lockers, cannot control when engaged
Prone to break

Logo quiz are of / from Automobile companies worldwide.

1. Guess the logo?
Hint:It is a Societas Europaea or European Public Company founded in 1931. It is a German holding company with investments in the automotive industry. Qatar Holdings also has 10% holding through the Qatar Investment Authority in it.

2. Guess the logo?
Hint:An automobile manufacturer based in the Czech Republic which became a wholly owned subsidiary of the Volkswagen Group in 2000.

3. Guess the logo?
Hint:It was established in February 1981, though the actual production commenced in 1983. In February 2012, the company sold its 10th million vehicle in India.

4. Guess the logo?
Hint:It formerly marketed vehicles under the "Datsun" brand name.

5. Guess the logo?
Hint:It is the automobile manufacturing division of Japanese transportation conglomerate Fuji Heavy Industries (FHI).

6. Guess the logo?
Hint:British luxury and sports car manufacturer, headquartered in Whitley, Coventry, England. It is part of the company which is a subsidiary of the Indian company Tata Motors.

7. Guess the logo?
Hint:It is the luxury vehicle division of Japanese automaker Honda Motor Company.

8. Guess the logo?
Hint:It is a French automaker producing cars, vans, and in the past, autorail vehicles, trucks, tractors, vans, tanks, and also buses/coaches.

9. Guess the logo?
Hint:It is the luxury division of automaker Nissan. It officially started selling vehicles on November 8, 1989 in North America.

10. Guess the logo?
Hint:It is the luxury vehicle division of Japanese automaker Toyota Motor Corporation. First introduced in 1989 in the United States, it is now sold globally and has become Japan's largest-selling make of premium cars.

11. Guess the logo?
Hint:It is the premium brand of cars named after its founder. Currently its holding pattern is Fiat S.p.A. (58.5%) and United Auto Workers (41.5%).

12. Guess the logo?
Hint:The company has its headquarters in Ingolstadt, Bavaria, Germany, and has been a wholly owned (99.55%)subsidiary of Volkswagen AG since 1966.

13. Guess the logo?
Hint:It is a Japanese automotive manufacturer based in Fuchū, Aki District, Hiroshima Prefecture, Japan.

14. Guess the logo?
Hint:It is a British manufacturer of luxury automobiles founded on 18 January 1919 by "W O".

15. Guess the logo?
Hint:It is a multinational division of the German manufacturer Daimler AG, and the brand is used for automobiles, buses, coaches, and trucks.

Carbon fiber, new aluminum structure lighten 2014 Corvette Stingray


The all-new 2014 C7 Corvette is a lightweight materials-fest. The base model gains a carbon-fiber hood (inner and outer) and roof panel. Quarters, doors, and hatch are in lighter-density SMC than the previous fenders, and the fascias are in TPO.

“We had very aggressive weight-reduction targets on this program,” said Leonard Brohl, Lead Engineer for Closure Panels on the 2014 C7 Chevrolet Corvette, unveiled Jan. 13 at a media event preceding the Detroit Auto Show. General Motors has resurrected the Stingray name for the latest generation of its iconic sports car, which continues to be a lightweight-materials wellspring for the automaker.

The C7, which enters production in 3Q13, boasts an all-new aluminum chassis/passenger cell structure that is 57% stiffer in torsion and 99 lb (45 kg) lighter than the previous C6 steel-and-aluminum structure, said GM engineers. At the car’s world debut, GM had not yet published a production curb weight for the car. It is expected to be slightly lighter overall than the base C6 coupe's 3208 lb (1455 kg).

Besides reducing mass while increasing strength, the development team aimed to retain the Corvette’s ideal 50/50 front/rear weight distribution deemed essential for superior handling.

Compared to the C6, which uses continuous hydroformed main frame rails with a constant 2-mm (0.08-in) wall thickness, the C7’s main rails each feature five aluminum segments, including extrusions at each end, a center main rail section, and hollow-cast nodes at the suspension interface points. Each segment is tuned by varying wall thickness from 2 to 11 mm (0.08 to 0.433 in). This tailors each section’s gauge, shape, and strength properties to optimize the structural requirements for each frame section while keeping mass to a minimum.

The frame is assembled at an all-new welding shop at the Bowling Green, KY, assembly plant using a precision laser welding process that GM claims holds tolerances to about 0.001 in (0.025 mm).

Supporting the frame’s greater strength and lower weight are complementing chassis elements, including hollow-cast aluminum front and rear cradles that are approximately 25% lighter and 20% stiffer than the solid cradles used on the C6 car’s structure. The steering column support is stiffened by a factor of five compared with the outgoing car using a new thin-wall magnesium casting.

C7’s use of materials includes a standard carbon-fiber hood and roof panel, supplied by Plasan Carbon Composites’ new Walker, MI, plant. Plasan has innovative manufacturing processes that shatter previous autoclave-type processing times, getting per-part processing down to 17-min machine cycles.

The unique balsa-wood-sandwich floor construction of the C6 Corvette has been superseded on C7 by a new carbon nano-composite floor pan that is lighter while maintaining strength and stiffness, said Chief Engineer Tadge Juechter.

C7’s front fenders, doors, rear quarter panels, and the rear hatch panel are made with lighter-density sheet molding compound (SMC) than the previous generation. The door outer panel measures 1.2 mm (0.047 in) thick and the inner panel 0.8 mm (0.031 in). Combined, the body materials and their design/engineering save approximately 37 lb (17 kg) vs. the C6 body structure.

C7 seat frames are a new magnesium structure on both the standard GT seat and the Competition Sport seat with more aggressive side bolstering.

Juechter said that the Stingray's 50/50 weight balance combined with its estimated 450 hp (335 kW) output (final SAE ratings are not yet finalized) offers the new Corvette a power-to-weight ratio that is superior to those of the Porsche 911 Carrera and Audi R8.

A Torsen limited-slip differential

A Torsen ("TORque SENsing") limited-slip differential isn't technically a limited slip differential. It's to call it just a Torsen differential or a helical differential.

The Torsen differential* is a purely mechanical device; it has no electronics, clutches or viscous fluids.

­The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.

These devices are often used in high-performance all-wheel-drive vehicles. Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs.

However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.



Hummer!

The HMMWV, or Hummer, uses Torsen® differentials on the front and rear axles. The owner's manual for the Hummer proposes a novel solution to the problem of one wheel coming off the ground: Apply the brakes. By applying the brakes, torque is applied to the wheel that is in the air, and then five times that torque can go to the wheel with good traction.

Inside Bruce Crower’s Six-Stroke Engine

Inside Bruce Crower’s Six-Stroke Engine

Bruce Crower has lived, breathed and built hot engines his whole life. Now he’s working on a cool one—one that harnesses normally-wasted heat energy by creating steam inside the combustion chamber, and using it to boost the engine’s power output and also to control its temperature.

“I’ve been trying to think how to capture radiator losses for over 30 years,” explains the veteran camshaft grinder and race engine builder. “One morning about 18 months ago I woke up, like from a dream, and I knew immediately that I had the answer.”

Hurrying to his comprehensively-equipped home workshop in the rural hills outside San Diego, he began drawing and machining parts, and installing them in a highly modified, single-cylinder industrial powerplant, a 12-hp diesel he converted to use gasoline. He bolted that to a test frame, poured equal amounts of fuel and water into twin tanks, and pulled the starter-rope.

“My first reaction was, ‘Gulp! It runs!’” the 75-year-old inventor remembers. “And then this ‘snow’ started falling on me. I thought, ‘What hath God wrought…’”

The “snow” was flakes of white paint blasted from the ceiling by the powerful pulses of exhaust gas and steam emitted from the open exhaust stack, which pointed straight up.

Over the following year Crower undertook a methodical development program, in particular trying out numerous variations in camshaft profiles and timing as he narrowed the operating parameters of his patented six-stroke cycle.

Recently he’s been trying variations of the double-lobe exhaust cams to delay and even eliminate the opening of the exhaust valve after the first power stroke, to “recompress” the combustion gasses and thus increase the force of the steam-stroke.

The engine has yet to operate against a load on a dyno, but his testing to date encourages Crower to expect that once he gets hard numbers, the engine will show normal levels of power on substantially less fuel, and without overheating.

“It’ll run for an hour and you can literally put your hand on it. It’s warm, yeah, but it’s not scorching hot. Any conventional engine running without a water jacket or fins, you couldn’t do that.”

Indeed, the test unit has no external cooling system—no water jacket, no water pump, no radiator; nothing. It does retain fins because it came with them, but Crower indicates the engine would be more efficient if he took the trouble to grind them off. He has discarded the original cooling fan.

So far he has used only gasoline, but Bruce believes a diesel-fueled test engine he is now constructing—with a hand-made billet head incorporating the one-third-speed camshaft—will realize the true potential of his concept.


Potential…and Questions

Crower invites us to imagine a car or truck (he speaks of a Bonneville streamliner, too) free of a radiator and its associated air ducting, fan, plumbing, coolant weight, etc.

“Especially an 18-wheeler, they’ve got that massive radiator that weighs 800, 1000 pounds. Not necessary,” he asserts. “In those big trucks, they look at payload as their bread and butter. If you get 1000 lb. or more off the truck…”

Offsetting that, of course, would be the need to carry large quantities of water, and water is heavier than gasoline or diesel oil. Preliminary estimates suggest a Crower cycle engine will use roughly as many gallons of water as fuel.

And Crower feels the water should be distilled, to prevent deposits inside the system, so a supply infrastructure will have to be created. (He uses rainwater in his testing.) Keeping the water from freezing will be another challenge.

But the inventor sees overriding benefits. “Can you imagine how much fuel goes into radiator losses every day in America? A good spark-ignition engine is about 24 percent efficient; ie., about 24 cents of your gasoline dollar ends up in power. The rest goes out in heat loss through the exhaust or radiator, and in driving the water pump and the fan and other friction losses.

“A good diesel is about 30 percent efficient, a good turbo diesel about 33 percent. But you still have radiators and heavy components, and fan losses are extremely high on a big diesel truck.”

Bottom-line, Bruce estimates his new operating cycle could improve a typical engine’s fuel consumption by 40 percent. He also anticipates that exhaust emissions may be greatly reduced. It’s all thanks to the steam.

“A lot of people don’t know that water expands 1600 times when it goes from liquid into steam. Sixteen hundred! This is why steam power is so good. But it’s dangerous…”

The danger of a boiler explosion has long been a factor in engineering—and in operating—steam powerplants of all kinds, and Crower is properly wary of the miniature boiler he has conjured up inside his test engine. That’s one reason he chose to use one originally manufactured as a diesel, for its inherent strength, though he installed a carburetor and ignition system so it could burn gasoline at first.

The original diesel fuel injector system now supplies the water spray to generate the steam-stroke.

In addition to producing extra power, the injected water cools the piston and exhaust valve, which suggests to Crower that he could raise the compression ratio. “I’ve done this many times on regular engines: 15-to-1 on gasoline for the first five seconds works pretty good until you get some chamber heat and then suddenly it gets into pinging. But with the chamber being chilled, I bet 12-, 13-to-1 will be no problem on cheap fuel.

“So what we can maybe do is have fuels that aren’t quite as good…It’ll save a nickel a gallon not having to keep three grades going.”

As for his hope of lowering emissions, Bruce speculates the steam might purge “cling-on hydrocarbons” out of the combustion chamber. “This thing may turn out to be so clean that you won’t have to have a catalytic converter.

But he admits that’s unknown, saying “there’s a lot of experimenting still to be done.” Which prospect makes him smile. He thrives on this kind of challenge.


Bruce’s Background

“You’ve kinda got to be in the cam business and know the dynamics of engines,” Bruce Crower says about how the idea occurred to him. And he certainly has that background.

He was building and racing hot rods (and hot bikes), manufacturing speed equipment and operating his own speed shop in his home town of Phoenix when he was still a teen.

After moving to San Diego in the 1950s, among other exploits he dropped a Hemi into a Hudson and drove it to a 157-mph speed record at Bonneville.

Inevitably, the inventive and inexhaustible Crower built up a major equipment business in superchargers, intake manifolds, clutches and, especially, camshafts. He’s also credited with first suggesting a rear wing to Don Garlits—in 1963, three years before Jim Hall’s winged Chaparral. Bruce Crower is now in Florida’s Drag Racing Hall of Fame.

Crower actually had introduced a wing two years earlier, during practice on Jim Rathmann's 1961 Indianapolis car—five years before Jim Hall’s winged Chaparral. Bruce had been crewing at the Speedway since 1954 (Jimmy Bryan, second place), and had been part of Rathmann's 1960 victory effort. He was likewise on the winning teams in 1966 (Graham Hill) and 1967 (AJ Foyt). Three decades later, in 1998, Eddie Cheever won with Crower cams.

Bruce even produced his own complete Indy engine, a flat-8 that didn’t quite make the field in 1977 and then was rendered obsolete (due to its width) by the advent of ground-effect tunnels. But the Crower 8 and its automatic clutch did win an SAE award for innovation.

Today, Crower Cams and Equipment Company employs about 160 people in five facilities, and manufactures not only cams but crankshafts and connecting rods—including titanium rods for (unnamed) Formula One customers.

Bruce Crower can’t be called retired now, but he’s happy to let the company he founded “roll along” while he “plays with cars.” That’s how he looks at the intensive R&D work he carries out in the privacy of his 13-acre horse property near the rural community of Jamul.

One of several projects is building up Honda S2000 engines for the Midget raced by his granddaughter, Ashley Swanson. (“I think she’s on par with Danica Patrick,” says the proud grampa.)

But his prime focus is proving his six-stroke engine is as revolutionary as he believes it is. “I’ve been trying to find something wrong with the whole basic idea for almost a year,” he says, “but I think we’re going to have a very marketable item.”

Then he adds philosophically, “If it turns out to be great, fine. If it doesn’t, it’s just another year out of my life that I’ve had a lot of fun doing something.”

Parx Super Car Show 2013 revs up Mumbai's weekend

 The fifth edition of the Parx Super Car Show took place at the Polo Grounds, RWITC (Mahalaxmi Race Course). Retired world champion rally driver Hannu Mikkola was present as the guest of honour. This year's event was divided into two days- day one being the static display and day two was the Super Car parade.

A major highlight of the show was the showcasing of the Lamborghini Aventador Roadster and the facelifted Audi R8. Also, the Y2k hyperbike was on display at the show.

Like its previous editions, the show displayed cars from manufacturers like Audi, Mercedes, Lamborghini, Aston Martin, Porsche, Ferrari, Bentley and Rolls-Royce for car enthusiasts in the city The second day of the event saw the super cars drive past the streets of Mumbai.

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