1. Introduction
torque and power, is one of the major automobile engine index, which reflects the performance in the car, including acceleration, climbing ability and suspension and so on. Its precise definition is: piston reciprocates in the cylinder, a reciprocating do have some power, its unit is Newton. In the work done per unit distance is the torque. This is, a measure of a car engine torque is an important criterion for good or bad, power is proportional to the size of a car engine torque.
For example popular, such as the human body as during exercise, the body is like a power durability, and torque is the body of the explosive. For the family car, the acceleration torque is higher the better; the greater the greater the degree of climbing for off-road vehicles, the torque; for trucks, the larger the torque the greater the weight of broaching. In the case of the same displacement, the engine torque is higher the better. While driving the car will feel anything, to accelerate can speed up, “push back” very good. Now there is an important evaluation of a car data, the car is the acceleration time from 0 to 100 km / h. And this torque acceleration time depends on the car engine.
In general, the highest index of the torque can be achieved at a rotation speed car 2000-4000 / min, preferably it means the car’s engine technology, power or. Some cars about speed 5000 / min to reach the highest index of torque the car, indicating that “power” is not a director of this car.
2 Overview
is a torque force for rotating an object occurs. The torque of the engine refers to an engine output torque from the crankshaft end. It is inversely proportional relationship with the engine speed, the faster the speed the smaller the torque in the fixed condition of the power, the greater the contrary, it reflects the car load capacity within a certain range.
In some cases the car can really reflect the “nature”, such as when starting or driving in the mountains, the higher the torque reaction of the car will run better. In comparison with the type of motor car, the greater the output torque greater carrying capacity,Better acceleration, climbing post stronger force, shift the number of the less wear and tear on the car will be relatively reduced. Especially when the car starts zero speed, but also shows a high torque by lifting fast advantages. Representation torque
Nm is an engine (N.m). The same power, as described generally in the maximum engine output torque is also marked revolutions per minute (r / min). Generally appear in the maximum torque, the low speed range of the engine, as the speed increases, but decreases torque.
3, the physical principles
Physics torque is the torque magnitude equal to the product of the force and the moment arm, is the international unit of Nm nm, can also be seen in addition kgm, lb-ft of torque such units, since G = mg, when g = 9.8 when the weight is 1kg 9.8N, so 1kgm = 9.8Nm, lb-ft lb-ft and is inch torque units, 1lb = 0.4536kg; 1ft = 0.3048m, can be calculated 1lb-ft = 0.13826kgm. In everyday expression, the torque is often referred to as torque (in physics this is two different concepts). For example: the 8th generation Civic1.8 of torque 173.5Nm@4300rpm, presentation engine 4300 rev / time-sharing output torque 173.5Nm, that 173.5N forces how to make more than one ton of cars running together? In fact, the engine torque is amplified to be emitted (the cost is reduced while the rotational speed) which rely on the transmission, and the final pass of the tires. Engine torque is released through the first transmission for “tunable” amplifying torque (or reduction ratio at ultra speeds) and then spread to the final pass (end banquet) was further amplified (while further reducing the rotational speed), and finally through the tire the driving force is released. 1 as a car speed gear ratio (the gear ratio of the gear, the gear ratio of the radius of essentially) is 3, 4 year-end party, the tire radius of 0.3 m, then the original torque is 200Nm, and finally becomes torsion axle 200 × 3 × 4 = 2400Nm (100 set the transmission efficiency percentage) after 0.3 meters divided by the tire radius, tire friction with the groundRub the part have 2400Nm / 0.3m = 8000N, that is the driving force of 800 kg force, which is sufficient to drive a car. If the mechanical efficiency addressed, each via a gear transmission, will have a loss of power, mechanical efficiency of a manual transmission of about 95 percentage, more miserable automatic transmission, about 88 percentage to about left, and the drive shaft universal joint efficiency about 98 percentage. Overall, the driving force of the car by the following formula: torque transmission gear ratio × × add that final gear ratio × mechanical efficiency / tire radius: Why the power can be calculated by the engine torque out of it? Power P = power W ÷ time t, and the work W = force F × distance S; Therefore, P = F × s / t = F × speed v v here is the linear velocity, and in the engines, the line speed of the crankshaft = crankshaft crankshaft angular velocity [omega] × radius r, is substituted into the above equation: P = power force F × r × radius the angular velocity [omega]; the force F × radius r = torque obtained: P = power [omega] the angular speed × torque of the engine so that the power from the torque and the calculated angular speed in radians / sec, a representative of π 180
radians in the 
4, the engine torque
SUMMARY
is that the torque force for rotating the object occurs. The torque of the engine refers to an engine output torque from the crankshaft end. It is inversely proportional relationship with the engine speed, the faster the speed the smaller the torque in the fixed condition of the power, the greater the contrary, it reflects the car load capacity within a certain range. In some cases the car can really reflect the “nature”, such as when starting or when traveling mountain, the higher the torque reaction of the car will run better. In comparison with the type of motor car, the greater the load greater the amount of torque output, better acceleration performance, stronger climbing force, forBlock number the less wear and tear on the car will be relatively reduced. Especially when the car starts zero speed, but also shows a high torque by lifting fast advantages.
representation
The method of representation is the engine torque Nm (N.m). The same power, as described generally in the maximum engine output torque is also marked revolutions per minute (r / min). Generally appear in the maximum torque, the low speed range of the engine, as the speed increases, but decreases torque.
physical principles
torque and power, it is one of the major automobile engine index, which reflects the performance in the car, including acceleration, climbing ability and the like. Its precise definition is: piston reciprocates in the cylinder, back and forth once will do some work, its international standard unit is Newton. In the work done per unit distance is the torque. Popular speak, a car engine torque is a measure of the quality of an important criterion, power is proportional to the size of a car engine torque. For popular example, play a very appropriate analogy, like the human body in motion as power is like the body’s durability, while torque is the body of the explosive. For the family car, the acceleration torque is higher the better; the greater the greater the degree of climbing for off-road vehicles, the torque; for trucks, the larger the torque the greater the weight of broaching. The torque is higher the better car, when traveling in the same way, in the case of the same displacement, the engine torque is higher the better. While driving the car will feel anything, to accelerate can be accelerated, “posted back a sense of” very good. Torque is one of the main parameter for evaluating the performance of a car. Now there is an important evaluation of a car data, the car is the acceleration time from 0 to 100 km / h. And this torque acceleration time depends on the car engine. In general, the maximum torque of the index can be achieved when the engine speed is relatively low, it means better process the car’s engine, the power of good, too. Some cars about speed 5000 / min to reach the highest index of torque the car indicating that “power” is not a director of this car. It can be said that we pursue driving pleasure mainly from the torque, the so-called “push back” if the maximum torque of the engine of a car appeared in the rev range we often use, so this car can definitely bring you extraordinary driving pleasure. For the family car, the perfect engine maximum torque at very low speed shouldIt appears, the maximum power occurs at relatively high speed.
5, formula
a whole driving force words, the car by the following equation: equation driving force transmission gear ratio = torque × × tire radius final gear ratio × ÷ mechanical efficiency (unit: m) Summary: 1kgm = 9.8Nm1lb-ft = 0.13826kgm1lb-ft = 1.355Nm displacement in certain circumstances, a small bore, the stroke length of the cylinder the torque more emphasis on play, the rotational speed will not be too high, applied to a vehicle requiring a large load. And a large bore, short stroke cylinder more emphasis on output power, typically high speed, the race is applied to a vehicle. Briefly: power is proportional to the rotational speed × torque. Why computing power can be calculated by the engine torque? Power P = power W ÷ time t work W = force F × distance s therefore, P = F × s / t = F × speed v v here is the linear velocity, and in the engines, the line speed of the crankshaft = crank angular velocity [omega] × crank radius r, is substituted into the above equation: P = power force F × r × radius the angular velocity [omega]; the force F × radius r = torque obtained: P = power [omega] the angular speed × torque of the engine so that the power from the torque and speed the calculated angular velocity radians / sec, a π representatives 180
6 in radians, the automobile driven theory
by
of the vehicle must rely on engine played torque, so-called of torque called torque in physics.
concept of torque from the lever to the principles described in elementary school, and is defined as a vertical force multiplied by the distance from the center of rotation, metric units of Newton – meter (Nm), divided by the gravitational acceleration 9.8m after / sec2, units can be converted to people familiar with kg – m (kg-m). Imperial units, compared with pounds – feet (lb-ft), in the United StatesCatalog more common on cars, to convert to metric, as long as the digital lb-ft can be divided by 7.22.
vehicle drive force calculated:
The torque divided by the engine power to the wheel radius – output torque graph can be found in each of the rotational speed has a relatively torque values, how to convert these values to the actual car driven power? The answer is simple, it is divided by a length, force data can be obtained. For example, a 1.6-liter engine maximum torque may be approximately 15.0kg-m, in which case if directly connected to the 185 / 60R14 size tire, a radius of about 41 cm, the driving force to wheels via a play 15 /0.41=36.6 kilograms of force (kg was not in fact the power of the unit, but the weight of the unit shall be multiplied by the acceleration due to gravity 9.8m / sec2 is the standard unit of force is Newton).
36 kg of force how to promote a tonne vehicle weight of it? Hundreds of thousands of revolutions and the engine speed becomes less likely to happen to the tire rotational speed, the gear is connected with a different size, the rotation speed can be reduced while the torque amplification. Due to the circumference of the gear ratio is the radius, and therefore to large power transmitted from the pinion gear, the speed reduction ratio of the rotation and the torque amplification factor, are exactly equal to the ratio of the number of teeth of the two gears, this ratio is called gear ratio.
illustrate
In the large gear driven by the pinion, assuming the number of teeth pinion gear 15, the large gear teeth is 45 teeth.
When the pinion gear to rotate at 3000rpm, and the torque of 20kg-m, the rotational speed of the transmission gear will be reduced Tai 1/3, it becomes 1000 rpm for; but instead enlarged to three times the torque became 60kg-m. This is the engine torque via the transmission speed can be reduced and the torque amplification basic principles.
in the car, until the engine output torque of the tire were amplified twice, the first gear is generated by the action of the gearbox, the second guide by the final gear ratio (or the final transmission ratio). Torque is multiplied by the total magnification ratio and the final gear ratio of the transmission gear ratio. For example, hand row of six generations Kimi a gear ratio of 3.250, the final gear ratio is 4.058, while the maximum torque of the engine is 14.6kgm / 5500rpm, so we can calculate the maximum torque of the first gear after amplification was 14.6 × 3.250 × 4.058 = 192.55kgm, magnified 13 times than the original engine. At this time, divided by the tire radius of about 0.41m, the thrust can be obtained is about 470 kg. However, the above values are not the actual thrust, after all, the process must have mechanical transmission of abrasion loss, it must be taken into account mechanical efficiency factor.
addressed mechanical efficiency, each via a gear transmission, will have a loss of power, manual transmission mechanical efficiency of about 95 percentage, more miserable TRANSMISSIONS, about 88 percentage to about left, and the efficiency of the drive shaft universal joint is about 98 percentage, you take a ride on their own to see that the actual number of left thrust. Overall, the driving force of the car is calculated by the following formula:
× torque transmission gear ratio of a final gear ratio × × mechanical efficiency
= drive force ———— ——–
of the tire radius (in meters)
horsepower is not in fact a force, but a power (the power) of the unit, the unit of time is defined as the You can work size. Power is calculated by the torque, and the formula is quite simple: Power (W) = 2π × torque (Nm) × speed (rpm) / 60, the simplified calculation becomes: Power (kW) = Torque (Nm) × speed (rpm) / 9549, detailed derivation see box article. But how to convert the power kW common people horsepower it.
English or Metric?
1PS = 735W; 1hp = 746W
horsepower Definitions
British horsepower (hp) is defined as: a horse in one minute to 200 lbs (LB) weight objects pull 165 feet (. ft), after multiplication equals 33,000ft-lb / min; and metric horsepower (PS) is defined compared to a horse in a minute object 75 kg pull 60 meters multiplied after equal to 4500kg-m / min. After conversion unit, (1lb = 0.454kg; 1ft = 30.48cm) actually found 1hp = 4566kg-m / min, and 1PS = 4500kg-m of slightly different metric,And if the power W (1W = 1Nm / sec = 1 / 9.8kgm / sec) equivalent to it, can be obtained 1hp = 746W; 1PS = 735W two different results. And the difference between 1PS 1hp only 1.5 weight percent, per hundred horsepower difference 1.5, the difference is not great. General car horsepower most only 200 horsepower or less, and both left and right due to the difference is only defined 3 horsepower, the plurality of data SAE standard 1.5 percentage it! But we can not really draw a little difference between the unit between SAE, JIS, DIN, EEC variety of testing standards are also equal sign, but not very much difference under the circumstances, is or PS hp, almost all can be seen as equal. After
conversion formula
obtained above horsepower and the power conversion method substituting the conversion formula of power and torque, and the torque of the unit in terms of familiar kg-m, can be obtained the following results: bhp hp = torque (kg-m) × engine speed (RPM) / 727 metric horsepower PS = torque (kg-m) × engine speed (rpm) / 716 from hp hp = torque × speed / 727, if they can increase the engine rotation speed, torque is not a case where the change, can increase horsepower. For example if the rotational speed increased from 6000rpm 8000rpm, means an increase in the percentage of 33, but because of limitations of the camshaft such that the torque 8000rpm when dropped 10 percentage, the percentage can still make 19.7 horsepower increase, which explains why today’s computer adapted after a substantial increase in horsepower to lift off the oil. If at the same speed, an increase of 20 horsepower, the number of representatives to increase the thrust of it? The maximum torque point to play in the case of 5000rpm, the minor physical formula, may be found to increase the torque = 20hp × 727 / 5000rpm = 2.9kgm. This result is then substituted into the formula car driving force, the same joy beauty of a file calculated, 2.9 × 3.250 × 4.058 / 0.41 = 93 kg. For the one-ton vehicle, the impact does not seem to how large; Furthermore if a difference of 5 horsepower, it increased by only 23 kg more thrust, showing a difference of 5 horsepower, there is also not much worse.
decided to really high-powered performance
in the end high-powered car to run fast, or high torque car run fast?
From equation may beTo know the reason for the high-powered high speed when still retains high torque values, that is to have high-powered, not only better low-speed torque, speed high torque even had to continue to maintain that this debate represents the torque and horsepower simply redundant, can be done as long as the high-powered, in addition to that of each of the torsion rotation region are large, the more the superiority of the representative materials technology, will be reinforced with a lightweight piston, intake and exhaust valve and the weight of the material, in order to increase the engine speed.
Conversion Formula torque and power derivation
Suppose a radius of the circle as r (unit m), torque T (in units of Nm), the circumferential tangential direction ? force F = T / r, because power is defined as “work done per second”, the circumferential movement, the work is made per rotation: F × total length 2πr the circumferential F = T / r is calculated substituting , each turn made by the work work = F × 2πr = (T / r) × 2πr = 2πT
multiplied by the engine speed rpm is the work done per minute, but the power unit P is Nm / sec, so the need by 60, it is converted into work done per second. Into the formula: P = T2πrpm / 60, a constant after finishing can be obtained P (kW) = Trpm / 9545.
Power is transmitted by a vehicle engine to the wheels, and therefore require more than one set of gears have losses, if hp DIN is transmitted to the power measured on the wheel, then the same engine used on different models power output should be different, and again take bmw330 bmw530 compared, which are power 225hp / 5900rpm; conclusions on the false data or bmw, or it is measured is the net output of the engine.
7, the maximum torque
SUMMARY
generally appear in the maximum torque, the low speed range of the engine, as the speed increases, but decreases torque. The torque unit is Newton meters (N · m) or kg-meters (Kg · m). Design of the maximum torque of the engine intake system of the engine, fuel supply system and ignition system, in at a certain speed, the performance of these systems to achieve the best match, you can achieve the maximumTorque. Further, the engine power, torque and speed are associated specifically relationship: Power = K × speed × torque, where K is the conversion factor. Should weigh when choosing an engine about how fair use, not to waste the existing functionality. For example, Beijing has the necessary winter and summer air conditioning, in the choice of engine power must take into account not too small; just commuting car on the city ring road, there is no need to pick an excessive horsepower engine. As far as possible economic, rational matching engine.
The maximum torque values for instructions
value and the maximum torque of the description of a number of models: only 60.5 Alto maximum torque, the engine is in the range of 3000-4000 rpm, the mini car made, it maximum torque is quite small, can reach 110-120 higher but due to its displacement of only 0.8L; range of high-emission vehicles particularly, from 110-700 and more, the average domestic mid-range vehicles in the range of 200-350, wherein Maybach exelero ascent torque in cars reach 1020/2500 rpm. Sports car is generally high, 400,500 is very common, modern cool FX2.0 can only reach maximum torque 102/6000, off-road vehicles, domestic generally in the range of 180-300 in (of course also more domestic emissions small), higher imports, Europe is generally 400/4800, Land Rover Freelander 2004 only 240/3000, 300/1950 and only its guards. Bujiadiwei 16.4 terror torque 1250/2200 also ranked first sports car torque.
Calculation
Definition: angle between φ ——- sectional opposing; γ ——- shear strain; τ ——– shear stress; T ———- torque; r ———– radius; l ———– length of material. Relative rotation and shear strain relationship is: γ = φr / l shear strain and shear stress shear satisfy Hooke’s law: τ = Gγ (G is the shear modulus of the material) the relationship between the shear stress and torque is: T = τdA × r (× point multiplication)
8. the torque calculation method
= 9550 × torque motor power ÷ number of revolutions of the motor power input ratio × × using coefficients