The modern automotive brake system has been refined for over 100 years and has become extremely dependable and efficient.
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Saturday, May 12, 2012
Brakes
Coherent Perfect Absorbers
Recently, our group has been investigating the concept of a "time-reversed laser".
A laser is an optical system that supports purely-outgoing radiation patterns. Above the lasing threshold, it is inherently non-linear (click here for our research on nonlinearity in random lasers). However, a laser at threshold can be described using a simple linear wave equation, with an amplifying refractive index (i.e. complex, with a negative imaginary part).
Cars Engines
The engine is always referred to as the heart of a vehicle. It is connoted with the term heart because it is the most important part of a vehicle. An engine is a machine which converts energy to mechanical motion. It is the engine that converts the flow of a fluid into mechanical energy.
Most of the modern cars today are incorporated with an internal combustion engine. The internal combustion engine ignites a fuel along with an oxidizer in a combustion chamber. The high temperature and pressure produced by the combustion process directly applies force to the movable part of the engine which could be the piston or the turbine blades to generate mechanical energy or to enable the vehicle to move. |
Heat Stove Fabrication (using an original hot air choke carb on an aftermarket intake)
To utilize an original hot air type automatic choke on an engine with no hot air provisions, it is first necessary to understand how and why the choke is designed to function. This LINK will help.
One must fabricate a “heat stove” to provide heat to the automatic choke. This may be done as follows:
(1) Take the carburetor to your local auto parts store. Have the clerk determine the thread size of the male threaded extension on the choke housing (assuming your automatic choke has the connection on the housing, and not in the center of the choke).
Automatic chokes
History
Automatic chokes were introduced at least by the early 1930’s. These early chokes were of the “divorced” or remote style, so named because the choke unit usually resided on the exhaust manifold and was remote from or divorced from the carburetor. These units consisted of a metal box that contained a coil of bimetallic strip which would expand/contract with heat/cool and which was connected to a rod that also connected to the choke arm on the carburetor. These units were not overly reliable, and in fact, most manufacturers build a manual override into the carburetor so that the operator has positive control over the choke. One issue with the divorced chokes was the choke had to move the mass of the connecting rod as well as operate the choke plate.
Automatic chokes were introduced at least by the early 1930’s. These early chokes were of the “divorced” or remote style, so named because the choke unit usually resided on the exhaust manifold and was remote from or divorced from the carburetor. These units consisted of a metal box that contained a coil of bimetallic strip which would expand/contract with heat/cool and which was connected to a rod that also connected to the choke arm on the carburetor. These units were not overly reliable, and in fact, most manufacturers build a manual override into the carburetor so that the operator has positive control over the choke. One issue with the divorced chokes was the choke had to move the mass of the connecting rod as well as operate the choke plate.
Carburetor fuel valves (a.k.a. needle and seat assembly)
There are a number of different designs of fuel valves that the enthusiast will encounter when working on carburetors. This article will describe the ones most commonly found in older vehicles.
Conventional pointed valve with brass seat
This valve is the valve of choice for virtually all original applications. There are a number of variations of the valve: monel steel tipped solid valve, monel steel tipped valve with spring and plunger, neopreme tipped solid valve, neopreme tipped valve with spring and plunger, plastic solid valve, and brass or monel steel solid valve, with neopreme washer encapsulated in the seat.
Conventional pointed valve with brass seat
This valve is the valve of choice for virtually all original applications. There are a number of variations of the valve: monel steel tipped solid valve, monel steel tipped valve with spring and plunger, neopreme tipped solid valve, neopreme tipped valve with spring and plunger, plastic solid valve, and brass or monel steel solid valve, with neopreme washer encapsulated in the seat.
Thursday, May 10, 2012
Motorcycle Types
Roper Steam Cycle
If a two-wheeled vehicle powered by steam propulsion is a true motorcycle, then the invention must be traced back to an American inventor by the name of Sylvester Howard Roper. Roper's steam-cycle hit the streets in 1869, well before the invention of the safety bicycle. The machine was powered by a charcoal-fired two-cylinder engine, with connecting rods attached to a crank on the rear wheel. However, the Roper motorcycle still placed the rider over a large front wheel.
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Motorcycles come in many different styles, each offering design and performance characteristics to accommodate specific riding conditions. Let's take a look at the common categories of motorcycles.
Examples of touring motorcycles (left) and cruisers (right)
Street Bikes
Street motorcycles come with all of the necessary equipment to be street-ready. They have lights, mirrors, a horn and a muffler. Their tires have a tread pattern that provides good traction on both wet and dry roads. Street motorcycles generally come in two forms -- touring motorcycles and cruisers. Touring motorcycles are specially designed for long-distance travel. Their most distinctive features are fairings, aerodynamic wind guards that wrap around the headlight to enhance styling and reduce drag.
Street motorcycles come with all of the necessary equipment to be street-ready. They have lights, mirrors, a horn and a muffler. Their tires have a tread pattern that provides good traction on both wet and dry roads. Street motorcycles generally come in two forms -- touring motorcycles and cruisers. Touring motorcycles are specially designed for long-distance travel. Their most distinctive features are fairings, aerodynamic wind guards that wrap around the headlight to enhance styling and reduce drag.
Motorcycle Transmission
by William Harris
A simple transmission
A simple transmission
A motorcycle engine can create an enormous amount of power, which must be delivered to the wheels of the vehicle in a controllable way. The motorcycle transmission delivers power to the rear wheel through a series of structures that include the gearset, theclutch and the drive system.
Motorcycle Engine
Motorcycle engines work the same way that car engines do. They consist of pistons, a cylinder block and a head, which contains the valve train. The pistons move up and down in the cylinder block, driven by explosions of a fuel-air mixture that has been ignited by a spark. Valves open and close to allow the fuel-air mixture to enter the combustion chamber. As the pistons move up and down, they turn a crankshaft, which transforms the energy from the pistons into rotary motion. The rotational force of the crankshaft is transmitted, via the transmission, to the rear wheel of the motorcycle.
Motorcycle engines are generally classified by one of three characteristics: the number of cylinders they possess, the capacity of their combustion chambers or the number of strokes in their power cycles.
Wednesday, May 9, 2012
Volvo claims World Hybrid Truck speed record
By Gizmag Team
Volvo’s hybrid truck, ‘Mean Green’, established new world speed records on April 27th at Wendover Airfield in Utah, USA.Mean Green
Image Gallery (6 images)
You will see a lot of stories around the web this week indicating that Volvo’s "Mean Green" truck has established a new world speed record. Volvo neglected to mention in the press release that it was the world hybrid truck speed record it had attained and hundreds of sites regurgitated the release verbatim without thought. The world land speed record is 1227 km/h - the Volvo ran about 1000 km/h slower than that.
BMW Daimler electric car project
Mercedes-Benz parent company Daimler and BMW are typically seen facing off against each other to win the hearts, minds and wallets of luxury car buyers. However, the challenges of developing a mass-produced electric car have inspired the two pillars of German luxury to put aside their rivalry and team up on a city car project.
Automatic transmission problem
Vehicles encounter automatic transmission problems usually on the basis of one or two particular factors. These are abuse and low fluid levels. Of course, one factor is capable of influencing the other, in that low fluid levels may be caused by abuse or may in turn reduce the amount of abuse that an automatic transmission can endure without failing.
Diesel Fuel Injection
One big difference between a diesel engine and a gas engine is in the injection process. Most car engines use port injection or a carburetor. A port injection system injects fuel just prior to the intake stroke (outside the cylinder). A carburetor mixes air and fuel long before the air enters the cylinder. In a car engine, therefore, all of the fuel is loaded into the cylinder during the intake stroke and then compressed. The compression of the fuel/air mixture limits the compression ratio of the engine -- if it compresses the air too much, the fuel/air mixture spontaneously ignites and causes knocking. Because it causes excessive heat, knocking can damage the engine.
Diesel engines use direct fuel injection -- the diesel fuel is injected directly into the cylinder.
The injector on a diesel engine is its most complex component and has been the subject of a great deal of experimentation -- in any particular engine, it may be located in a variety of places.
How fuel injection sistem work
By karim nice
Introduction
In trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years. The 1990 Subaru Justy was the last car sold in the United States to have acarburetor; the following model year, the Justy had fuel injection. But fuel injection has been around since the 1950s, and electronic fuel injection was used widely on European cars starting around 1980. Now, all cars sold in the United States have fuel injection systems.
Volkswagen crowdsources its way to a Hover Car
The world of personal mobility transporters doesn't bring a whole lot of glamor. The Segway was never exactly an enviable ride, and newer concepts like the GM EN-Varen't any better. But a Volkswagen that hovers a few feet over the ground? That channels a mix of Back to the Future and The Jetsons that adds some excitement to the personal mobility segment.
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