Bicycle speedometers

Typical bycycle speedometers measure the time between each wheel revolution, and give a readout on a small, handlebar-mounted digital display. The sensor is mounted on the bike at a fixed location, pulsing when the spoke-mounted magnet passes by. In this way, it is analogous to an electronic car speedometer using pulses from an ABS sensor, but with a much cruder time/distance resolution - typically one pulse/display update per revolution, or as seldom as once every 2–3 seconds at low speed with a 26-inch (2.07m circumference, without tire) wheel. However, this is rarely a critical problem, and the system provides frequent updates at higher road speeds where the information is of more import. The low pulse frequency also has little impact on measurement accuracy, as these digital devices can be programmed by wheel size, or additionally by wheel or tire circumference in order to make distance measurements more accurate and precise than a typical motor vehicle gauge. However these devices carry some minor disadvantage in requiring power from batteries that must be replaced every so often (in the receiver AND sensor, for wireless models), and, in wired models, the signal being carried by a thin cable that is much less robust than that used for brakes, gears, or cabled speedometers.

Other, usually older bicycle speedometers are cable driven from one or other wheel, as in the motorcycle speedometers described above. These do not require battery power, but can be relatively bulky and heavy, and may be less accurate. The turning force at the wheel may be provided either from a gearing system at the hub (making use of the presence of e.g. a hub brake, cylinder gear or dynamo) as per a typical motorcycle, or with a friction wheel device that pushes against the outer edge of the rim (same position as rim brakes, but on the opposite edge of the fork) or the sidewall of the tyre itself. The former type are quite reliable and low maintenance but need a gauge and hub gearing properly matched to the rim and tyre size, whereas the latter require little or no calibration for a moderately accurate readout (with standard tyres, the "distance" covered in each wheel rotation by a friction wheel set against the rim should scale fairly linearly with wheel size, almost as if it was rolling along the ground itself) but are unsuitable for off-road use, and need to be kept properly tensioned and clean of road dirt to avoid slipping or jamming.

innova specification

ENGINE TYPE DIESEL Grade G V Z X X X   7-Seater 8-Seater 7-Seater 8-Seater 7-Seater

DIMENSIONS

Overall Length 4585 mm Overall Width 1765 mm Overall Height 1760 mm Wheelbase 2750 mm Tread Front / Rear 1510 mm / 1510 mm Min. Turning Radius 5.4 m Fuel Tank Capacity 55 litres

WEIGHTS

Max. Kerb Weights 1675 kg 1680 kg 1700 kg Gross Weight 2300 kg 2300 kg 2300 kg

ENGINE

Type BS III: 2KD-FTV, Diesel with Turbocharger, 4 inline cylinder BS IV: 2KD-FTV, Diesel with Intercooler Turbocharger, 4 inline cylinder Valve Train 16 Valve DOHC Displacement 2494 cm³ (cc) Fuel Supply System Common-Rail Max. Output 75 kW @ 3600 rpm (102 PS @ 3600 rpm) Max. Torque BS III - 200 Nm @ 1400-3400 rpm (20.4 kg-m @ 1400-3400 rpm) BS IV - 200 Nm @ 1200-3600 (20.4 kg-m @ 1200-3600 rpm)

CHASSIS & TRANSMISSION

Suspension Front / Rear Double Wishbone / Four Link with Lateral Rod Brakes Front/Rear Ventilated Disc / Leading-Trailing Drum Tyres 205/65 R15 Tubeless Radials Transmission 5 Speed Manual

EXTERIOR FEATURES

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Fuel tank construction

While most tanks are manufactured, some fuel tanks are still fabricated by metal craftsmen or hand-made in the case of bladder-style tanks. These include custom and restoration tanks for automotive,aircraft, motorcycles, and even tractors. Construction of fuel tanks follows a series of specific steps. The craftsman generally creates a mockup to determine the accurate size and shape of the tank, usually out of foam board. Next, design issues that affect the structure of the tank are addressed - such as where the outlet, drain, fluid level indicator, seams, and baffles go. Then the craftsmen must determine the thickness, temper and alloy of the sheet he will use to make the tank. After the sheet is cut to the shapes needed, various pieces are bent to create the basic shell and/or ends and baffles for the tank. Many fuel tanks' baffles (particularly in aircraft and racecars) contain lightening holes. These flanged holes serve two purposes, they reduce the weight of the tank while adding strength to the baffles. Toward the ends of construction openings are added for the filler neck, fuel pickup, drain, and fuel-level sending unit. Sometimes these holes are created on the flat shell, other times they are added at the end of the fabrication process. Baffles and ends can be riveted into place. The heads of the rivets are frequently brazed or soldered to prevent tank leaks. Ends can then be hemmed in and soldered, or flanged and brazed (and/or sealed with an epoxy-type sealant) or the ends can be flanged and then welded. Once the soldering, brazing or welding is complete, the fuel tank is leak-tested.

Operation of alternator

Typical passenger vehicle and light truck alternators use Lundell or 'claw-pole' field construction. This uses a shaped iron core on the rotor to produce a multi-pole field from a single coil winding. The poles of the rotor look like fingers of two hands interlocked with each other. The coil is mounted axially inside this and field current is supplied by slip rings and carbon brushes. These alternators have their field and stator windings cooled by axial airflow, produced by an external fan attached to the drive belt pulley.

Compact alternator

Modern vehicles now use the compact alternator layout. This is electrically and magnetically similar, but has improved air cooling. Better cooling permits more power from a smaller machine. The casing has distinctive radial vent slots at each end and now encloses the fan. Two fans are used, one at each end, and the airflow is semi-radial, entering axially and leaving radially outwards. The stator windings now consist of a dense central band where the iron core and copper windings are tightly packed, and end bands where the windings are more exposed for better heat transfer. The closer core spacing from the rotor improves magnetic efficiency. The smaller, enclosed fans produce less noise, particularly at higher machine speeds.

Larger vehicles may have salient pole alternators similar to larger machines.

There are two separate types of alternators: the Delta set-up and the Wye set-up.

marine sextant

The second critical component of celestial navigation is to measure the angle formed at the observer's eye between the celestial body and the sensible horizon. The sextant, an optical instrument, is used to perform this function. The sextant consists of two primary assemblies. The frame is a rigid triangular structure with a pivot at the top and a graduated segment of a circle, referred to as the "arc", at the bottom. The second component is the index arm, which is attached to the pivot at the top of the frame. At the bottom is an endless vernier which clamps into teeth on the bottom of the "arc". The optical system consists of two mirrors and, generally, a low power telescope. One mirror, referred to as the "index mirror" is fixed to the top of the index arm, over the pivot. As the index arm is moved, this mirror rotates, and the graduated scale on the arc indicates the measured angle ("altitude").

The second mirror, referred to as the "horizon glass", is fixed to the front of the frame. One half of the horizon glass is silvered and the other half is clear. Light from the celestial body strikes the index mirror and is reflected to the silvered portion of the horizon glass, then back to the observer's eye through the telescope. The observer manipulates the index arm so the reflected image of the body in the horizon glass is just resting on the visual horizon, seen through the clear side of the horizon glass.

Adjustment of the sextant consists of checking and aligning all the optical elements to eliminate "index correction". Index correction should be checked, using the horizon or more preferably a star, each time the sextant is used. The practice of taking celestial observations from the deck of a rolling ship, often through cloud cover and with a hazy horizon, is by far the most challenging part of celestial navigation.

Speed Sensitive Steering

An outgrowth of power steering is speed sensitive steering, where the steering is heavily assisted at low speed and lightly assisted at high speed. The auto makers perceive that motorists might need to make large steering inputs while manoeuvering for parking, but not while traveling at high speed. The first vehicle with this feature was the citroen sm with its diravi layout although rather than altering the amount of assistance as in modern power steering systems, it altered the pressure on a centring cam which made the steering wheel try to "spring" back to the straight-ahead position. Modern speed-sensitive power steering systems reduce the mechanical or electrical assistance as the vehicle speed increases, giving a more direct feel. This feature is gradually becoming more common.