You will have read in many manuals or technical data sheets of cars the concept of "torque", also known as "torque"It is a fairly common term, but not many people know what it is, or how it can affect performance or daily life.
For this reason, we are going to look at a deep level What does this term refer to, and why is it important? when choosing the engine…
What is torque?
El Torque, also known as torque, is a physical quantity that represents the capacity of a force to produce a rotation around an axis.In the context of engines, whether electric, hybrid, or internal combustion, torque is the measure of the force that the engine exerts on the crankshaft to generate motion, which is then transmitted to the wheels via the transmission. In simpler terms, it is the twisting force that drives the wheels of a vehicle.
La formula which defines this pair is:
τ = F × r
Where τ (tau) is the torque (expressed in Newton meters, N m), F is the applied force in Newtons (N), and r is the perpendicular distance from the line of action of the force to the axis of rotation (in meters, m).
El The torque developed by an engine depends on several factors, among them:
- Engine design: Of course, the power developed by the engine will influence the torque developed. For example, factors that can influence it are the displacement, whether or not it has a turbo (with a turbo it increases compared to a naturally aspirated engine with the same characteristics), etc. The octane rating of the fuel used, the fuel-air mixture, etc. can also affect the torque. Another important factor is the transmission, the gearbox can also affect this.
- RPM: The engine's rotation speed, i.e. the revolutions per minute, can also influence the torque. In fact, the maximum torque specified by car manufacturers is usually reached at a specific speed. That is, above this speed no more torque is achieved, and below this speed neither.
It is also important to know the torque curve. It is a graphical representation that shows how the engine torque varies depending on the revolutions per minute (RPM). This curve is characteristic of each engine and provides valuable information about its performance, as you can see how the car behaves at different engine speeds. This can be important, depending on the engine speed at which you want to achieve maximum torque.
Power vs Torque
Power and torque are two fundamental concepts in the world of motors, but they are often confused. Although they are closely related, they represent different aspects of an engine's performance. For example, when we talk about power, we refer to the rate at which work is doneIn an internal combustion engine, it represents the amount of energy that the engine can convert into work per unit of time.
Power (P) = Force (F) × Speed (v)
Power (P for rotary engine) = Torque (τ) × Angular velocity (ω)
This power is measured in the SI in kW (kilowatts), although generally, for cars, it is better to use CV or horsepower. In technical manuals, it is usually given in SI, that is, in kilowatts. To convert from kW to CV is very easy:
From HP to kW:
1 HP ≈ 0.7355 kW
kW = HP * 0.7355
From kW to HP:
1 kW ≈ 1.3596 hp
HP = kW * 1.3596
This is how equivalences can be made between electric and combustion engines. For example, a 200 HP combustion engine corresponds to approximately 147.1 kW, or what is the same, 147.100 W. An electric motor with 68 kW of power would be equivalent to approximately 91 HP.
Power and torque are closely linked related through angular velocity:
Power = Torque × ω
This means that for a given angular velocity or ω (revolutions per minute), higher torque means higher power. However, it is important to note that the torque curve is not constant throughout the entire rev range, as I mentioned earlier.
What does torque affect?
Now that you know what torque is, you're probably also wondering what does engine torque influence, to better guide you when choosing your future engine. Well, it influences:
- Acceleration: An engine with high torque at low revs can be said to provide quicker acceleration from a standstill and a more agile response to gear changes. This translates into a greater feeling of thrust. Although maximum power is usually achieved at high revs, engine torque also plays an important role. An engine with a flat torque curve extended towards high revs will allow sustained acceleration at high speeds.
- Towing capacity: High torque makes it easier to overcome steep slopes, as it can apply greater force to the drive wheels. Vehicles designed to tow heavy loads usually have engines with high torque at low revs, which allows them to maintain a constant speed and overcome resistance to movement. This is the case for off-road vehicles, as well as trucks, heavy vehicles, tractors, etc.
- Engine elasticity: An engine with a broad torque curve allows you to drive at low revs in high gears without having to constantly downshift and accelerate. This translates into lower fuel consumption and more relaxed driving. On the other hand, when performing a recovery (accelerating from a low speed in a high gear) to overtake, a high torque engine will allow you to perform the manoeuvre more quickly and safely.
- Driving sensation: A high torque engine conveys a feeling of strength and solidity to the driver, resulting in a more satisfying driving experience. An engine with a quick throttle response, usually associated with high torque at low revs, provides a feeling of agility and control.
Now, the question is… how much torque is enough? This will depend on your needs, the weight of the vehicle, whether you mainly drive on the highway or in the city, whether you frequently face steep slopes or not, and so on.
Images | canva