Trainer, Mechanical Engineering Department- PurpleLeap
I had a student, Deepak (name masked), who was an automobile enthusiast. Not really! During our casual conversation by the road side a vehicle zoomed past us. He immediately squealed “Do you know that it’s a SX4, it’s been recently rolled out by Maruti Suzuki and blahblahblahblah?” He was excited to offload the information to me and was firing on all cylinders. I gazed at him for some time and bowled a googly, I asked him “do you know that the vehicle’s engine is equipped with the VVT technology?” Of course, I wanted to remind him that I am his Sir and not the other way. He was stumped and appeared like a dog with its tail between the legs, totally petrified and surrendered. Anyways, that wasn’t the intention.
After a moment of silence, he gently whispered, “What is VVT, Sir?” Now, it was my turn to fire on all cylinders. You know, every dog has its day!
I asked him, “Deepak, do you breathe?” He looked puzzled and replied, uhh, yup. Then, VVT is all about breathing of an engine. This time, he was completely taken aback. “#%%%&&###!!$$$!!!$&*#@@!!+++”, precisely, this was going-on in his mind, looked utterly confused.
With a deep voice, like a frog in his throat, he said, “I am not able to understand this breating-veathing of engines, would you be clearer?”
I thought, before things get worse with him let me break the ice.
VVT is the technology all about breathing of an engine efficiently. Like human beings the engines also breathe. After this statement of mine, he appeared as though he had a close brush with death.
Engines inhale the fresh charge i.e. air-fuel mixture for gasoline engines and air for diesel engines. In humans, the inhaled air enters the lungs through nostrils and in engines the fresh charge enters the cylinder through inlet valves. The way we exhale the air again through nostrils to evacuate the lungs to accommodate the next cycle of fresh air, the engine also exhales the burnt gases through the outlet valves to receive the next cycle of fresh charge. This cycle of inhale-exhale continues for ever. Not literally! The confused soul was getting convinced and was settling down like a fizz of the soda after some time.
To give a personal touch to the explanation I asked him a simple question. “Will the rate at which you inhale and exhale the same during watching a movie, jogging and desperately being chased by a dog?”
He replied “Obviously, no”. I could see the gleam in his eyes when he answered. I said “That’s right!” The rate of inhaling and exhaling is the least while watching a movie, it becomes faster when we are jogging and becomes the fastest when being aggressively chased. In the same sense, engine also performs a similar activity i.e. watching a movie can be compared to the idling state of the engine at the traffic signal, jogging is similar to a vehicle moving at some 20 to 30 KMPH (not precisely) and aggressive spring is similar to a vehicle cruising at 100 KMPH (not exactly) over a high way.
In a nut shell, depending on the speed of the engine the charge that is sent to the engine needs to be maneuvered and that is done by varying the timing of the inlet and outlet valves. The technology which maneuvers the timing of the valves depending on the speed is called as Variable Valve Timing i.e. VVT.
By the time my explanation was done, his 6 O’clock face turned to 10:10 face. He suddenly uttered “Sir, you are also VVT.” This time he bowled a googly, to retaliate my earlier ones. I gave a blank stare. With lot of reverence, head bowed down with his sight on the third button of his shirt he said “VVT, I meant, Very Very Talented.” I couldn’t hold myself and busted out with a boisterous laughter and departed with a happy ending!
I hope this conversation must have elicited the meaning of VVT technology in the vehicles.
I have a small quiz for the readers which is rewarding. Reward?? Yes, I’ll come to that a bit later. First things first, what is a VTEC technology? Is it similar to VVT?
The reward would a best-selling e-copy of an Automobile book.
In the next series I’ll bring the technical details of VVT. Misotechnologist,please excuse.
Till then, bye. Take Care.