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Short Shifting
Short shifting is a driving technique in which the gear is changed up before reaching maximum engine RPM or, more precisely, the acceleration optimized RPM shift-point. By short shifting, the engine does not reach its power band, and therefore maximum vehicle acceleration is not attained for the gear from which the short shift was performed. In racing, short-shifting is a technique intended to avoid losing valuable acceleration time changing gears later. Although this means not being able to accelerate using the engine's peak power at the moment of the gear change, total acceleration overtime may be greater as no acceleration can happen during the gear change. This can aid overtaking by ensuring that the car is in the right gear in anticipation of a maneuver. The most common reason for a short-shift in day-to-day driving is to improve fuel economy. By keeping the engine at the lower end of its RPM range less fuel is consumed. This is especially common in "torquey" vehicles, vehicl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gear Ratio
A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage. Gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, providing a smooth transmission of rotation from one gear to the next. Features of gears and gear trains include: * The gear ratio of the pitch circles of mating gears defines the speed ratio and the mechanical advantage of the gear set. * A planetary gear train provides high gear reduction in a compact package. * It is possible to design gear teeth for gears that are non-circular, yet still transmit torque smoothly. * The speed ratios of chain and belt drives are computed in the same way as gear ratios. See bicycle gearing. The transmission of rotation between contacting toothed wheels can be traced back to the Antikythera mechanism of Greece and the south-pointing chariot of China. Illustrations by the Renaissance scientist Georgius Agricola show gear trains with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Combustion Engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons ( piston engine), turbine blades (gas turbine), a rotor (Wankel engine), or a nozzle ( jet engine). This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. This replaced the external combustion engine for applications where the weight or size of an engine was more important. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1860, and the first modern internal combustion engine, known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Band
The power band of an internal combustion engine or electric motor is the range of operating speeds under which the engine or motor is able to output the most power, that is, the maximum energy per unit of time. This usually means that maximum acceleration can be achieved inside this band (often at the cost of lower efficiency). While engines and motors have a large range of operating speeds, the power band is usually a much smaller range of engine speed, only half or less of the total engine speed range (electric motors are an exception—see the section on electric motors below). Specifically, power band is the range of RPM around peak power output. The power band of an internal combustion gasoline automobile engine typically starts at midrange engine speeds (around 4,000 RPM) where maximum torque is produced, and ends below the redline after reaching maximum power (above 5,000 RPM but less than 7,000 RPM). Diesel engines in cars and small trucks may develop maximum torque b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overtaking
Overtaking or passing is the act of one vehicle going past another slower moving vehicle, travelling in the same direction, on a road. The lane used for overtaking another vehicle is often a passing lane farther from the road shoulder which is to the left in places that drive on the right and to the right in places that drive on the left. Rules of overtaking In English-speaking countries On a single-carriageway/undivided-highway road, the lane used for overtaking is often the same lane that is used by oncoming traffic. An overtaking vehicle must be able to see clearly ahead of them for the entire overtaking manoeuvre plus a margin of error. For example, in New Zealand it's instructed in the Road Code that an overtaking driver must be able to see at least of clear road in front of them as they finish the passing manoeuvre. In the UK, guidance for passing and overtaking is given in rules 162-169 of the Highway Code. In some jurisdictions, the "overtaking zone" is indicated b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Progressive Shifting
Progressive shifting is a technique for changing gears commonly practiced by drivers of semi-trailer trucks. It is meant to reduce fuel consumption — something very important for drivers who travel several hundred miles each day. Progressive shifting is accomplished by changing gears upward as early as possible when accelerating, while staying within the flat torque range. Each shift will go a little higher into the RPM, until the vehicle is in its top gear at cruising speed. After each shift is completed, the engine and transmission should be operating at or near the lowest rpm speeds recommended by the manufacturers of those parts. The fastest acceleration is achieved when the truck is receiving as close as possible to maximum power throughout the entire time it is accelerating. E.g. in a truck with a Caterpillar C15 engine it is achieved by going all the way up to 1950RPM, then shifting to a gear that will put the engine at 1500RPM. In contrast, using progressive shift ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
