Audi Q3 2.0 TDI Quattro base

Engine and Transmission

EngineDisplacement (CC)

1968 cc

No Of Cylinders

4 Cylinder

No Of Gears

7 Speed

Power (PS)

177 PS

Torque (NM)

380Nm

Transmission

S tronic

Kerb Weight

1660 kgs.

Fuel Type

Diesel

Drive Type

AWD

Fuel Economy

City (KPL)

Data Not Available

Highway (KPL)

Data Not Available

Overall (KPL)

11.72 (ARAI)

Performance

060 kph (sec)

Data Not Available

0100 kph (sec)

8.2 seconds (Claimed)

Top Speed (KPH)

230 (Claimed)

Brakes Steering Suspension and Tyres

Brakes Front

Disc Brake

Brakes Rear

Disc Brake

Steering Type

Rack and Pinion

Minimum Turning Radius

5.9

Suspension Front

McPherson spring strut type axle with lower wishbones and aluminium subframe

Suspension Rear

4-link rear axle with separate spring/damper arrangement

Tyre Size

215/65 R 16

Wheel Size

16

Exterior Dimensions

Length Width Height

4385*2019*1608

Wheelbase(mm)

2603 mm

Ground Clearance (mm)

Data Not Available

Track Front (mm)

901 mm

Track Rear (mm)

881 mm

Interior Dimensions

Boot (Litres)

460 Litres

Fuel Capacity (Litres)

64 Litres

Seating Capacity

5

Westinghouse Air Brake Company

The Westinghouse Air Brake Company was established by George Westinghouse in 1869. The Air Brake plant was moved to wilmerding pennsylvaniain1889. Wilmerding is a small town about 14 miles outside of Pittsburgh which, at the time, was only inhabited by about 5,000 people. socialism was strong in Wilmerding and it was a peaceful non-violent farming borough. It was thought to be “The Ideal Town” for the company because of its location right along the  pennsylvania railroad and its mainly blue collar inhabitants. The Air Brake Company employed 3,000 citizens from the surrounding Pittsburgh area, but its work force was composed almost entirely of individuals from Wilmerding.

This stretch of lightly populated farmland known as Wilmerding developed completely around this new and industrially important company and was finally put on the map. A little under one third of its population was somehow related and more often than not one would end up raising their children in the same home that they were raised in. After the company's development business thrived. Many of the passengers that were departing or coming into Wilmerding stopped to shop at these stores along the narrow sidewalk before heading home. One could get anything from hair cuts to comic books, groceries to lumber; Wilmerding was where you would find it.

Working conditions at the Westinghouse Air Brake Company (WA&B) were more than proficient and the company had many new developments in effect for its employees. In 1869 it was one of the first companies to institute a 9-hour work day and a 55-hour work week. WA&B also got the reputation for being the first industry in America to adopt half holidays on Saturday afternoons. A series of welfare options were also instituted to better the working and living conditions of its employees.

The Air Brake plant was obviously very prosperous and was nothing far from a gift for this small town. By 1905 over 2,000,000 freight, passenger, mail, baggage, and express cars and 89,000 locomotives were equipped with the Westinghouse Air Brakes. But just as in all big businesses, it had its ups and downs. There was one general complaint among the Wilmerding business men. It was that only about half of the workers could find work during the non-busy season. This made sense since these men and women depended entirely on the company. When the economy struggled and profits in the company declined, workers then had to alter their standard of living. Wilmerding’s prosperity and misfortune all depended on the success of the Air Brake Company and when the company was failing the citizens just had to try and adjust to its losses.

During this time, in the early 1900s, the Westinghouse Company built houses on a tract of land that it had purchased, in turn, it then sold those homes to its workers at a very inexpensive price. The company also offered educational and cultural activities, usually run through the local Y.M.C.A, to obtain better workers. WA&B catered to those who were not exactly fit in its working conditions. To insure a certain income to employees who might have been unfit for work because of illness or injury, an ordered sum would be paid to the beneficiary. Any employee under 50 was eligible for membership after a physical examination. The members contributed according to the class which they belonged, with their class being determined by the amount of money they made per month. Their contribution ranged from fifty cents to $1.50, which in turn in case of disability would receive benefits for thirty-nine consecutive weeks. According to Wilmerding News during this time, about 76% of WA&B’s employees held a membership with the company.

The Westinghouse Air Brake company was still producing products up until around the year 2000, under several different managers over the years. The company had become significantly less important with the shedding of Pittsburgh’s industrial past, but continued manufacturing its products.

The company has two 21st century successors, which are independent of each other. One, which continues to design and manufacture railway air brakes in Wilmerding, Pennsylvania, merged with locomotive manufacturer MotivePower Industries, to form  wabtac. The other, now known as WABCO Holdings Inc, designs and manufactures control systems for commercial road vehicles, including air brakes, and is headquartered in  brussels Belgium. was floated in a 2007 initial public offering by A S, WABCO's owners for 30 years.

Advantages of air brake

Air brakes are used as an alternative to hydraulic brakes which are used on lighter vehicles such as automobiles. Hydraulic brakes use a fluid  to transfer pressure from the brake pedal to the brake shoe to stop the vehicle. Air brakes have several advantages for large multitrailer vehicles:

• The supply of air is unlimited, so the brake system can never run out of its operating fluid, as hydraulic brakes can. Minor leaks do not result in brake failures.
• Air line couplings are easier to attach and detach than hydraulic lines; there is no danger of letting air into hydraulic fluid. So air brake circuits of trailers can be attached and removed easily by operators with little training.
• Air not only serves as a fluid for transmission of force, but also stores potential energy. So it can serve to control the force applied. Air brake systems include an air tank that stores sufficient energy to stop the vehicle if the compressor fails.
• Air brakes are effective even with considerable leakage, so an air brake system can be designed with sufficient "fail-safe" capacity to stop the vehicle safely even when leaking.

pneumatic starting motor

Some gas turbine engines and  diesel engines, particularly on trucks, use a pneumatic self-starter. In ground vehicles the system consists of a geared turbine, an air compressor and a pressure tank. Compressed air released from the tank is used to spin the turbine, and through a set of reduction gears, engages the ring gear on the flywheel, much like an electric starter. The engine, once running, drives the compressor to recharge the tank.

Aircraft with large gas turbine engines are typically started using a large volume of low-pressure compressed air, supplied from a very small engine referred to as an auxiliary power unit, located elsewhere in the aircraft. Alternately, aircraft gas turbine engines can be rapidly started using a mobile ground-based pneumatic starting engine, referred to as a start cart or air start cart.

On larger diesel generators found in large shore installations and especially on ships, a pneumatic starting gear is used. The air motor is normally powered by compressed air at pressures of 10–30 BAR. The AIR motor is made up of a center drum about the size of a soup can with four or more slots cut into it to allow for the vanes to be placed radially on the drum to form chambers around the drum. The drum is offset inside a round casing so that the inlet air for starting is admitted at the area where the drum and vanes form a small chamber compared to the others. The compressed air can only expand by rotating the drum, which allows the small chamber to become larger and puts another one of the cambers in the air inlet. The air motor spins much too fast to be used directly on the flywheel of the engine; instead a large gearing reduction, such as a planetary gear, is used to lower the output speed. A Bendix gear is used to engage the flywheel.

Large Diesel generators and almost all Diesel engines used as the prime mover of ships use compressed air acting directly on the cylinder head. This is not ideal for smaller Diesels, as it provides too much cooling on starting. Also, the cylinder head needs to have enough space to support an extra valve for the air start system. The air start system is conceptually very similar to a distributer a car. There is an air distributor that is geared to the camshaft of the Diesel engine; on the top of the air distributor is a single lobe similar to what is found on a camshaft. Arranged radially around this lobe are roller tip followers for every cylinder. When the lobe of the air distributor hits one of the followers it will send an air signal that acts upon the back of the air start valve located in the cylinder head, causing it to open. Compressed air is provided from a large reservoir that feeds into a header located along the engine. As soon as the air start valve is opened, the compressed air is admitted and the engine will begin turning. It can be used on 2-cycle and 4-cycle engines and on reversing engines. On large 2-stroke engines less than one revolution of the crankshaft is needed for starting.

Since large trucks typically use air brakes, the system does double duty, supplying compressed air to the brake system. Pneumatic starters have the advantages of delivering high torque, mechanical simplicity and reliability. They eliminate the need for oversized, heavy storage batteries inprime mover electrical systems.

Power brakes

The vacuum booster or vacuum servo is used in most modern hydraulic brake systems which contain four wheels. The vacuum booster is attached between the master cylinder and the brake pedal and multiplies the braking force applied by the driver. These units consist of a hollow housing with a movable rubber diaphragm across the center, creating two chambers. When attached to the low-pressure portion of the throttle body or intake manifold of the engine, the pressure in both chambers of the unit is lowered. The equilibrium created by the low pressure in both chambers keeps the diaphragm from moving until the brake pedal is depressed. A return spring keeps the diaphragm in the starting position until the brake pedal is applied. When the brake pedal is applied, the movement opens an air valve which lets in atmospheric pressure air to one chamber of the booster. Since the pressure becomes higher in one chamber, the diaphragm moves toward the lower pressure chamber with a force created by the area of the diaphragm and the differential pressure. This force, in addition to the driver's foot force, pushes on the master cylinder piston. A relatively small diameter booster unit is required; for a very conservative 50% manifold vacuum, an assisting force of about 1500 N (200n) is produced by a 20 cm diaphragm with an area of 0.03 square meters. The diaphragm will stop moving when the forces on both sides of the chamber reach equilibrium. This can be caused by either the air valve closing (due to the pedal apply stopping) or if "run out" is reached. Run out occurs when the pressure in one chamber reaches atmospheric pressure and no additional force can be generated by the now stagnant differential pressure. After the run out point is reached, only the driver's foot force can be used to further apply the master cylinder piston.

The fluid pressure from the master cylinder travels through a pair of steel brake tubes to a pressure differential valve, sometimes referred to as a "brake failure valve", which performs two functions: it equalizes pressure between the two systems, and it provides a warning if one system loses pressure. The pressure differential valve has two chambers (to which the hydraulic lines attach) with a piston between them. When the pressure in either line is balanced, the piston does not move. If the pressure on one side is lost, the pressure from the other side moves the piston. When the piston makes contact with a simple electrical probe in the center of the unit, a circuit is completed, and the operator is warned of a failure in the brake system.

From the pressure differential valve, brake tubing carries the pressure to the brake units at the wheels. Since the wheels do not maintain a fixed relation to the automobile, it is necessary to use hydraulic brake hose from the end of the steel line at the vehicle frame to the caliper at the wheel. Allowing steel brake tubing to flex invites metal fatigue and, ultimately, brake failure. A common upgrade is to replace the standard rubber hoses with a set which are externally reinforced with braided stainless-steel wires; these have negligible expansion under pressure and can give a firmer feel to the brake pedal with less pedal travel for a given braking effort.

Power valve of carburetor

For open throttle operation a richer mixture will produce more power, prevent pre-ignition detonation, and keep the engine cooler. This is usually addressed with a spring-loaded "power valve", which is held shut by engine vacuum. As the throttle opens up, the vacuum decreases and the spring opens the valve to let more fuel into the main circuit. On two stroke engines the operation of the power valve is the reverse of normal — it is normally "on" and at a set rpm it is turned "off". It is activated at high rpm to extend the engine's rev range, capitalizing on a two-stroke's tendency to rev higher momentarily when the mixture is lean.

Alternative to employing a power valve, the carburetor may utilize a metering rod or step-up rod system to enrich the fuel mixture under high-demand conditions. Such systems were originated by Carter Carburetor in the 1950s for the primary two venturis of their four barrel carburetors, and step-up rods were widely used on most 1-, 2-, and 4-barrel Carter carburetors through the end of production in the 1980s. The step-up rods are tapered at the bottom end, which extends into the main metering jets. The tops of the rods are connected to a vacuum piston and/or a mechanical linkage which lifts the rods out of the main jets when the throttle is opened (mechanical linkage) and/or when manifold vacuum drops (vacuum piston). When the step-up rod is lowered into the main jet, it restricts the fuel flow. When the step-up rod is raised out of the jet, more fuel can flow through it. In this manner, the amount of fuel delivered is tailored to the transient demands of the engine. Some 4-barrel carburetors use metering rods only on the primary two venturis, but some use them on both primary and secondary circuits, as in the Rochester Quadrajet.

Principles of carburater

The carburetor works on Bernoulli's principle: the faster air moves, the lower its static pressure and the higher its dynamic pressure. The (accelerator) linkage does not directly control the flow of liquid fuel. Instead, it actuates carburetor mechanisms which meter the flow of air being pulled into the engine. The speed of this flow, and therefore its pressure, determines the amount of fuel drawn into the airstream.

When carburetors are used in aircraft with piston engines, special designs and features are needed to prevent fuel starvation during inverted flight. Later engines used an early form of fuel injection known as a pressure carburetor.

Most production carbureted  engines have a single carburetor and a matching intake manifold that divides and transports the air fuel mixture to the intake valesi, though some engines (like motorcycle engines) use multiple carburetors on split heads. Multiple carburetor engines were also common enhancements for modifying engines in the USA from the 1950s to mid-1960s, as well as during the following decade of high-performance muscle cars fueling different chambers of the engine's .intake manifold

Older engines used updraft carburetors, where the air enters from below the carburetor and exits through the top. This had the advantage of never flooding the engine as any liquid fuel droplets would fall out of the carburetor instead of into the intake manifold; it also lent itself to use of an oil bath air cleaner where a pool of oil below a mesh element below the carburetor is sucked up into the mesh and the air is drawn through the oil-covered mesh; this was an effective system in a time when paper air filters did not exist.

Beginning in the late 1930s, downdraft carburetors were the most popular type for automotive use in the united states. In Europe, the sidedraft carburetors replaced downdraft as free space in the engine bay decreased and the use of the su-type carburetor (and similar units from other manufacturers) increased. Some small propeller-driven aircraft engines still use the updraft carburetor design.

outboard moter carburetors are typically sidedraft, because they must be stacked one on top of the other in order to feed the cylinders in a vertically oriented cylinder block.

1979 Evinrude Type I marine sidedraft 

carburetorThe main disadvantage of basing a carburetor's operation on Bernoulli's principle is that, being a fluid dynamic device, the pressure reduction in a venturi tends to be proportional to the square of the intake air speed. The fuel jets are much smaller and limited mainly by viscosity, so that the fuel flow tends to be proportional to the pressure difference. So jets sized for full power tend to starve the engine at lower speed and part throttle. Most commonly this has been corrected by using multiple jets. In SU and other movable jet carburetors, it was corrected by varying the jet size. For cold starting, a different principle was used in multi-jet carburetors. A flow resisting valve called a choke, similar to the throttle valve, was placed upstream of the main jet to reduce the intake pressure and suck additional fuel out of the jets.