Saturday, December 05, 2020

Why could the concept of a single-clutch automated-manual transmission be still relevant?

There were times when a very same car could differ considerably from a region to another regarding the availability of automatic transmissions, even for models with a broader "World's car" appeal such as the Toyota Corolla. At its 9th generation (E120), it resorted to a narrower bodyshell for both the European and Japanese markets, even though the lower demand for automatic transmissions in Europe rendered it more suitable to make an automated-manual transmission available instead. As it retained the coupling through friction from a regular manual instead of resorting to a hydraulic torque converted usually fitted to conventional automatics, gear changes are often more noticeable according to the driver's behavior, which might seem more annoying to a Japanese or American more used to a greater smoothness that a single-clutch automated-manual transmission is reportedly unable to provide.

While both the evolution of conventional automatics, CVTs and the arrival of the dual-clutch automated transmissions could sound like the end of the road for a single-clutch AMT, it retains a foothold on the commercial vehicles segment. Considering aspects such as purchasing price, maintenance schedule and concerns related to the impact of an automatic transmission on both fuel consumption and payload, the simpler layout of an automated-manual seems more appealing to fleet managers and owner-operators in countries such as Brazil where the commercial vehicles market is highly conservative. Even though the rougher operation and usage of a conventional clutch which still needs replacements through the useful operating life of a truck such as the Volkswagen Constellation or a bus such as the Volkswagen 17.230 OD may sound disadvantageous compared to an automatic transmission, maintenance procedures more similar to what most commercial operators are comfortable with is likely to render them more favorable to a single-clutch automated-manual transmission.
It's also worth to remind some claims of longer clutch life due to clutchless gear changes which happen more frequently, and a lower fuel consumption because of the automatic selection of the more suitable gear according to traffic and terrain conditions, at a cost premium not as high as for an automatic and a lower increase to the curb weight of the vehicle. The increased precision of the newer electronic engine management systems has also led to the viability of a more accurated and better integrated transmission control, preventing driver errors such as over-revving which is detrimental to the fuel consumption. It's worth to remind the viability to expand the concept of single-clutch automated-manual transmissions to nearly any vehicle with a modern engine electronic management system, rendering it an effective way to increase comfort, durability and fuel-efficiency even for vehicles which were never available with an automatic transmission, to the point that even modern versions of the classic Lada Niva with sequential port-injection and distributorless ignition could benefit from this feature.

Besides the lower cost comparing a single-clutch automated-manual transmission to both an automatic or a dual-clutch transmission, rendering it a good option for emerging markets where the economics of scale can be favored by sharing most components with the regular manual transmissions on cars such as the Volkswagen Fox, it's also noticeable the failures on single-clutch AMTs is usually more related to electro-hydraulic actuators than to the internals of the gearbox or the clutch pack, while for dual-clutch transmissions it's not unusual to have clutch pack failures which may damage the entire transmission. A simpler approach may not provide all the advantages from its more sophisticated counterparts, such as the claimed seamless and faster shift which rendered DCTs widely praised, but a lower overall cost is worth to consider. So, even though it might not be always understood by the average Joe, the concept of a single-clutch automated-manual transmission is still relevant.

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