Background AUTOMATIC.
Automated transmissions were developed early in the inception of cars with internally-combusted engines. Diverse mechanisms were devised to autonomously operate gear changes benefitting from distinct ratios between engine and wheel motion. The most common device in automobiles is a hydraulically-operated one, using fluid coupling or a torque converter and a set of planetary gearsets providing different ratios.
The introduction of automatic gearboxes in transit was anthropologically significant as it allowed far larger populations to drive vehicles, including people who had learned to drive at a late age or people simply not apt to operate the mechanism of manual gearboxes (coordinating clutch pedal + gear stick + throttle pedal). This fact is important as the formidable societal transformation of the transition to an individually mobile society and the economic and industrial transformation of Western economies after Second World War were both brought about by the massive socialisation, production and use of automobiles. Individual transportation benefitted business operability and efficiency as employees and business partners gained greater geographic mobility but also individuals, as this increased, more flexible mobility allowed an enhanced disposal of time and space in the private sphere.
These facts, however, only marginally explain the recent trend increasing the proportion of cars with automated transmissions in the car market; this tendency rather follows a very concrete commercial strategy by car manufacturers. Automated transmissions (automatics and semi-automatics) tend to be subject to marginally fewer mechanical breakdowns than manuals, notably those derived by engine over-revving, and also tend to be involved in marginally fewer road accidents. Additionally, engines matted to automatics tend to be better conserved over time and generate lower warranty costs. These facts also redound in lower insurance rates and higher resale values for used cars. These facts have hence moved manufacturers to equip these more costly gearboxes to their models, more notably so in the case of premium manufacturers, as higher resale values for used cars move customers to opt for more similarly priced, brand new vehicles.
Background SEMI-AUTOMATIC.
The commercial policy described above is more financially beneficial to premium manufacturers as initial purchase costs are often more flexible than those for more economic cars. In this trend, manufacturers of so called sports and race cars, such as Ferrari, Porsche, Lamborghini, BMW and others, began to progressively fit automated gearboxes to their vehicles as well, seeking, however, to provide devices that allowed drivers to operate gear changes manually, even if not through direct, mechanical commands.
Automated gearboxes with drivers input were devised by motor sport teams in categories such as Formula 1 and World Rally Championship in the late 1980s, seeking to improve mechanical reliability but also time efficiency, reducing the lapse of gear-ratio changes. These devices finally became standard in both categories by the mid 1990s.
There are two basic types of semi-automatic transmissions: Planetary, torque-converting automatic transmissions fitting devices that allow electronic inputs by the driver to operate gear selections; they are far less expensive and are correspondingly more commonly fitted. The second type is that of manual gearboxes fitting individual motors operating clutch activation, gearset engagement and throttle coordination; they are in general much more expensive and fitted less frequently (e.g. Ferrari and some BMW models).
The greatest disadvantage of automated manuals seems to lie in the less accomplished operation of changes. Drivers commands are always integrated via electronic inputs (clutch-less stick or, more commonly, so called flappy-paddles behind the steering wheel) within the computerised systems of the vehicle: engine-, traction-, stability-, brake- and more recently (electro-hydraulic) steering-management. This often results in gear-change orders delayed until the rest of the car management is adapted or even orders ignored if the system esteems them less dynamically efficient.
Manufacturers have justified the fitting of semi-automatics with a claimed gain in time efficiency, rendering a car marginally faster as dead times, clutch intervals, are said to be operated faster. The most recent device in this trend is the dual-clutch transmission (DCT), in which an additional clutch pre-engages the next gear to that transmitting motion, so that when the order for a gear change is given the next gear is immediately operative. Several independent tests have, however, shown virtual equivalence in most cases or, in some cases, even a persisting greater time efficiency of manuals.
[SEE, RELATED: Background MANUAL in PART II...]
