What are the “cons” of driving at low engine speeds
Old-school motorists often prefer to drive at low revs and advise this riding style to friends. The main advantages of this method are the reduction in fuel consumption, less noise inside the car from the engine and, as it were, an increasing motor resource. So, do you really need to stick to this recommendation?
First, find out what similar low revs and what they give. Low revs mean such a mode of operation of the power unit in which it works at the limit, that is, the car moves at a higher gear than the situation on the road requires. For gasoline naturally aspirated units, this mode is up to 2.5 thousand revolutions per minute, and for diesel ones – up to 1.1 thousand – 1.2 thousand revolutions per minute.
It is a similar driving mode that many motorists consider economical. In theory, the fuel economy scheme works extremely simply: the less rotations the engine produces per 1 unit. the distance traveled, the less fuel is consumed. Partly this formula is true, but not every time.
Let’s imagine a situation where a car moves evenly at low speeds and it needs to accelerate. This can be done in 2 ways: sharply pressing the gas pedal, while maintaining the selected gear, or by going down a step. In the 1st case, the engine, already working at a heavy load, receives a large portion of fuel, and also chokes, because stays outside the torque shelf; in the 2nd, it goes into the optimum mode in terms of load. Owners of vehicles with an on-board PC can see for themselves that even higher fuel consumption will be spent on an oversized transmission – until the engine reaches its optimal operating mode.
At the same time, processes occur in the power unit itself, about which it will also be worthwhile for every car owner to know.
Firstly, when operating at reduced speeds, unpleasant vibrations occur in the power unit caused by detonation. You probably felt them when you traveled with “professionals” – by taxi, bus or your own TC. Their appearance is a sure sign that the driver literally kills the car. Vibrations destroy bearings and motor shafts, transmission, clutch and motor mounts. The pistons, liners of the crankshaft, 2-mass flywheel (if equipped with a car) are subject to increased wear, the GPM chain is stretched, and carbon deposits quickly increase in combustion chambers.
Secondly, increased wear of engine components occurs due to their insufficient lubrication. This is due to the dependence of the oil pump pressure on the speed of the crankshaft: the sliding bearings are designed to work in conditions of hydrodynamic lubrication (oil flows under pressure into the gaps between the shaft and liners). So, the greater the speed, the higher the pressure. Engine running at low speeds, experiencing oil starvation.
And finally, riding at low speeds is simply unsafe: in case of urgent need to accelerate, doing it in high gear will simply not work out quickly. An increase in fuel supply does not lead to a sharp and steady acceleration, which means that there is a high risk of an accident.
That is why it is important to remember that the car’s engine actively wears out when most car owners try to “save”: the maximum load is imposed on low revs, which is why the wear rate of the motor components in the zone of towing operation is.
Our advice is simple: if you feel a decrease in speed or vibration that was caused by motor overload, immediately switch to a lower gear. Also try not to bring this up and keep the crankshaft rotations in the medium range (usually 2.5 thousand-4 thousand revolutions per minute for a naturally aspirated gasoline engine) and sometimes burn carbon deposits in the combustion chambers and the catalyst, briefly spinning the power unit to revolutions exceeding average . Thus, you can extend the engine and your iron friend as a whole.
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