Gate valve

A gate valve is a valve that opens by lifting a round or rectangular gate out of the path of the fluid. The distinct feature of a gate valve is the sealing surfaces between the gate and seats are planar. The gate faces can form a wedge shape or they can be parallel. Gate valves are sometimes used for regulating flow, but many are not suited for that purpose, having been designed to be fully opened or closed. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low friction loss.

Gate valves are characterised as having either a rising or a nonrising stem. Rising stems provide a visual indication of valve position. Nonrising stems are used where vertical space is limited or underground.

Bonnets provide leakproof closure for the valve body. Gate valves may have a screw-in, union, or bolted bonnet. Screw-in bonnet is the simplest, offering a durable, pressure-tight seal. Union bonnet is suitable for applications requiring frequent inspection and cleaning. It also gives the body added strength. Bolted bonnet is used for larger valves and higher pressure applications.

Another type of bonnet construction in a gate valve is pressure seal bonnet. This construction is adopted for valves for high pressure service, typically in excess of 2250 psi. The unique feature about the pressure seal bonnet is that the body - bonnet joints seals improves as the internal pressure in the valve increases, compared to other constructions where the increase in internal pressure tends to create leaks in the body-bonnet joint.

Globe valves

Globe valves are named for their spherical body shape. The two halves of the valve body are separated by a baffle with a disc in the center. Globe valves operate by screw action of the handwheel. They are used for applications requiring throttling and frequent operation. Since the baffle restricts flow, they're not recommended where full, unobstructed flow is required.

A bonnet provides leakproof closure for the valve body. Globe valves may have a screw-in, union, or bolted bonnet. Screw-in bonnet is the simplest bonnet, offering a durable, pressure-tight seal. Union bonnet is suitable for applications requiring frequent inspection or cleaning. It also gives the body added strength. Bolted bonnet is used for larger or higher pressure applications.

Many globe valves have a class rating that corresponds to the pressure specifications of ANSI 16.34. Other different types of valve usually are called globe style valves because of the shape of the body or the way of closure of the disk. As an example typical swing check valves could be called globe type.

VVT-i

VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 4A-GE 20-Valve engine. The VVT system is a 2-stage hydraulically controlled cam phasing system.

VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position. In 1998, 'Dual' VVT-i (adjusts both intake and exhaust camshafts) was first introduced in the RS200 Altezza's 3S-GE engine. Dual VVT-i is also found in Toyota's new generation V6 engine, the 3.5L 2GR-FE V6. This engine can be found in the Avalon, RAV4, and Camry in the US, the Aurion in Australia, and various models in Japan, including the Estima. Other Dual VVT-i engines will be seen in upcoming Toyota models, including a new 4 cylinder Dual VVT-i engine for the new generation 2007/2008 Corolla. Another notable implementation of the Dual VVT-i is the 2GR-FSE D-4S engine of the Lexus GS450h. By adjusting the valve timing, engine start and stop occur virtually unnoticable at minimum compression, and fast heating of the catalytic converter to its light-off temperature is possible, thereby reducing HC emissions considerably.

VTEC

VTEC (standing for Variable valve Timing and lift Electronic Control) is a system developed by Honda to improve the combustion efficiency of its internal combustion engines throughout the RPM range. This was the first system of its kind and eventually led to different types of variable valve timing and lift control systems that were later designed by other manufacturers (VVTL-i from Toyota, VarioCam Plus from Porsche, and so on). It was invented by Honda's chief engine designer Kenichi Nagahiro.

catalytic converter

A catalytic converter automobiles in the (colloquially, 'cat' or 'catcon') is a device used to reduce the toxicity of emissions from an internal combustion engine. First widely introduced on series-productionUS market for the 1975 model year to comply with tightening EPA regulations on auto exhaust, catalytic converters are still most commonly used in motor vehicle exhaust systems. Catalytic converters are also used on generator sets, forklifts, mining equipment, trucks, buses, trains, and other engine-equipped machines. A catalytic converter provides an environment for a chemical reaction wherein toxic combustion byproducts are converted to less-toxic gases. The catalytic converter was invented at Trinity College (Connecticut).

MegaSquirt

MegaSquirt is an aftermarket electronic fuel injection (EFI) controller designed to be used with a wide range of internal combustion engines. It is an open project headed by Bruce Bowling and Al Grippo, engineers that work on the U.S. East Coast. The project's do-it-yourself approach makes it the least-expensive system for this purpose. Basic costs are below US$200 as of 2005, although this can vary widely depending on application.

MegaSquirt is a successor of sorts to Bowling and Grippo's earlier EFI332 design, which was more complex yet more powerful system (at least initially). The EFI332 project started around 1995, and culminated in the release of about 200 kits in 2000. The system used a 32-bit MC68332 microcontroller from Motorola, hence the name. A steep learning curve is believed to have prevented the system from gaining wider acceptance.

The two engineers decided to simplify the design and focus on managing the fuel injectors (the EFI332 could also control the spark plug ignition system if so desired). The version 1.0 MegaSquirt used an 8-bit Motorola MC68HC908 microcontroller, but a later MegaSquirt-II upgrade included a 16-bit MC9S12. It is likely that a future version will use a 32-bit processor.

The assembled controller takes input from a few different sensors in order to manage the fuel injectors, including a throttle position sensor (TPS), exhaust gas oxygen sensor (EGO or O₂intake air temperature sensor (IAT), and a coolant temperature sensor sensor), MAP sensor, (CLT). The latter two sensors themselves are usually the General Motors type, although you can recalibrate the controller to use other sensors.

There are several related projects, including:

• MegaJoltLite – an ignition system controller for the Ford Enhanced Distributorless Ignition System (EDIS)
• UltraMegaSquirt – an integrated fuel injection and ignition controlle

Butterfly valve

A Butterfly valve is a type of flow control device, used to make a fluid start or stop flowing through a section of pipe. The valve is similar in operation to a ball valve. A flat circular plate is positioned in the center of the pipe. The plate has a rod through it connected to a handle on the outside of the valve. Rotating the handle turns the plate either parallel or perpendicular to the flow of water, shutting off the flow. It is a very robust and reliable design. However, unlike the ball valve, the plate does not rotate out of the flow of water, so that a pressure drop is induced in the flow.

There are three types of butterfly valve:

1. Resilient butterfly valve which has a flexible rubber seat. Working pressure up to 1.6 Mpa
2. High performance butterfly valve which is usually double eccentric in design . Working pressure up to 5.0 Mpa
3. Tricentric butterfly valve which is usually with metal seated design. Working pressure up to 10.0 Mpa

Butterfly valves are also commonly utilised in conjunction with carburetors to control the flow of air through the intake manifold and hence the flow of fuel and air into an internal combustion engine. The butterfly valve in this circumstance called a throttle as it is 'throttling' the engines aspiration. It is controlled via a cable or electronics by the furthest right pedal in the drivers footwell (although adaptions for hand control do exist). This is why the accelerator pedal in some countries is called a throttle pedal.