Thursday, 15 November 2018

LEARN ABOUT GEAR RATIOS AND THEIR IMPACT ON ACCELERATION AND MILEAGE


The vehicle's ratio can decide on its maximum speed, how fast reaches its maximum speed and how hard it must be. Car manufacturers must strike a balance between absolute performance and absolute fuel
economy when determining the final gear ratios. Too much equipment and some customers will complain that their vehicle is not economical enough, while others may complain that their vehicle is "gutless" with too little equipment.


Transmission indicators

Gearboxes and rear ends / differentials have both ratios. The gearboxes use gear ratios to keep the engine in a safe and economical speed range, while giving the vehicle the ability to accelerate and maintain a safe speed on the ground. Without gears, after reaching the redline of the engine, that would be it, no more acceleration; you are speeding up. Add another gear to the transmission, and you can turn it on and accelerate or maintain the current speed at a lower and more efficient speed.

Think about a bicycle with a derailleur and 10 or 12 or 18 speeds. You will use this lower gear to get out of the dead stop or climb up, and then you will go to a higher gear when you start to raise the speed. However, if you leave him in a lower gear, your legs will work quite hard (and inefficient), but you will not build any speed. In this case, the gears of the bicycle are both gearbox and final gear.

Different transmissions have different ratios depending on how the manufacturer expects them to be used. For example, the popular GM 4L60e automatic transmission has a ratio of 3.06 in the first, 1.62 in the second, 1.0 in the third and 0.70 in the fourth. Here's what these numbers mean:
  • The first gear provides the torque required for movement. In the first gear, the GM 4L60e transmission rotates the drive shaft by one complete revolution for every 3.06 revolutions of the engine (3.06: 1) to overcome inertia (the body at rest has a tendency to remain at rest until it acts by external force). 
  •  When it changes per second, each time the propeller shaft is rotating fully, the engine revolves      1.62   to provide mid-range torque when the vehicle overcomes inertia (1.62: 1).
  •       Now we are switching to the third gear to increase the city speed. On the third gear, each      time the engine performs a full rotation, the same happens with the drive shaft (1: 1).
  •       Hit the paver on the motorway and you need extra speed, which is ensured by the fourth    gear. The transmission now rotates the drive shaft through full revolution for every  7/10 engine revs (0.7: 1).  
 The fourth gear in the 4L60e model allows us to swim comfortably on interstates at speeds of 2500-3500 rpm instead of 4500-5500 rpm, saving gas and excessive engine wear. Gear ratios are what engineers call "torque multipliers." Larger numbers give greater torque faster to allow for better acceleration.

Let's compare this for example with the early sixties Ford, with the fourth gear in a ratio of 1: 1, the third at 1.69: 1, the second at 3.09: 1 and the first with a very short 6.32: 1. This first gear is commonly called "grandma's equipment", because the truck can not move much faster than the walking speed on this equipment. However, in the lorries, Grandma's equipment was common in terms of torque and pulling power.


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