Tachometer. How to read and use his testimony?
A tachometer in a car is not a fancy gadget. It is a useful device that can be used in many different ways.
If we do not look at the tachometer readings, we cannot accurately determine the rotational speed at which the main shaft of the engine of our car is moving. And it's worth knowing because it's extremely valuable information. Each drive has its own characteristics that determine how it behaves in everyday use. By monitoring the engine speed, you can use the characteristics to achieve certain advantages. Based on the engine speed, we can make the best use of engine dynamics when driving fast, or we can drive as calmly and smoothly as possible, achieving the lowest possible fuel consumption.
In order to use the tachometer accurately, the driver must have information about the characteristics of the engine. Without such knowledge, the tachometer will be just a useless element of the dashboard. It is important to know the torque curve, the course of its diagram and at what speed its maximum value occurs. It is also important to know at what rpm the maximum engine power appears, and at what rpm the torque and power diagrams intersect on the engine performance diagram.
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In dynamic or sporty driving, the goal is to keep the engine speed at a level that allows the maximum possible torque to be developed. Simply put, torque is responsible for acceleration, not maximum power. The engine operates most efficiently in the range between RPM with maximum torque and RPM with maximum power. The wider the range, the more flexible the motor. In day-to-day use, this means you can accelerate quickly in this speed range without changing gear ratios. Therefore, it is necessary to know and remember the speed range in which the engine has the greatest load-bearing capacity. To make it easier to enter marks on the tachometer. The ideal during the most efficient acceleration is to change gears at such moments that after the shift, the engine starts to accelerate from the speed at which it reaches or approaches maximum torque. Then he has the greatest ability to overcome the resistance to movement caused by the weight of the car, friction and air resistance. Additional information provided by the tachometer is the fact that the engine is reaching its maximum, safe RPM. This is indicated by a red field at the end of the scale and a cut-off in the injection system. Operating the engine outside the allowable RPM range may result in damage to the drive unit. Most often, the engine jams or the connecting rod breaks.
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When driving economically with an emphasis on the lowest possible fuel consumption, knowing the characteristics of the engine is also very useful. True, many drivers adhere to the principle that the slower the crankshaft rotates, the less fuel will pass through the combustion chambers, but there is a trap in this assumption. Well, the engine should not exceed a certain speed limit in each of the gears. The aim is to avoid harmful phenomena that greatly accelerate the wear of the input shaft bearings and connecting rod bearings. Driving too slowly is a kind of pseudo-economy. Efficient driving can be successfully combined with low fuel consumption, but this requires a tachometer and knowledge of engine characteristics. Ideally, to know the full external characteristics, with a fuel consumption graph (it is easy then to determine the most profitable speed). But even on the basis of the power-torque diagram, it is possible to determine the range of the most favorable revolutions in terms of fuel consumption. Their value is approximately half of the revolutions between maximum torque and maximum power. By keeping the engine close to this value by reading the tachometer, you will ensure a smooth ride and low fuel consumption.
