One frequent comment that people make about today’s new cars is that they all tend to look so much alike. Well, that’s true. The car designer’s dilemma is much the same as the clothing fashion designer’s quandary — to be innovative without being outlandish.
In the meantime, while most car companies are tending to be conservative with their styling they still have to differentiate themselves from the competition. In addition to distinguishing brands with variations on styling cues, car companies can entice you with their unique features. And since the early 1980s, the biggest growth area has been in new technology innovations.
One of the most pervasive new advancements into the masses of vehicle production have been in engine combustion technology. Getting the engine to breathe better has always been the way to increase horsepower and where multi-valve engines used to be more likely found in race cars or only high-performance street cars, today many family sedans have this feature. The question that might occur to you is, “Does a multi-valve cylinder head really make a difference?”
The “Multi-valve” Engine
Think of your engine as house through which you want to have a lot of fresh new air come through on a continual basis. Now, if you wanted to keep a steady flow of air getting in and out of your house with the least interruption, it would be best to have the air blow in the front door, and blow out through the back door.
Well, that’s how your engine works — except the “doors” are called valves and they regulate the flow of air/fuel gasses that enter your engine and are used in the engine’s explosions that propel your car.
Conventional engines use one “intake” valve and one “exhaust” valve to allow an incoming charge of air/fuel molecules to rush into the engine’s combustion chamber. For a split second, both valves (doors) are closed and the air/fuel mixture gets compressed, followed by the arrival of a quick “arc” of electricity from the spark plug — then the compressed air/fuel mixture ignites in a tightly contained explosion. Bingo. And next that power is converted into twisting motion through your engine’s crankshaft into the transmission, drive axles and finally to your vehicle’s wheels.
Now what? Oh yeah. Better open the other valve (door) to let out the exhaust from that combustion. So, “intake” — “combustion” — “power” and “exhaust.” That’s it! Now you’ve got the fundamentals of what you’ve heard called the “four stroke cycle.” Except for diesel-powered vehicles — which use a different combustion process — most vehicles today use that “four-stroke cycle.”
Okay, great. Now, what’s all this got to do with so-called multi-valve engines? Well, the idea of getting fresh air/fuel into and out of the engine quickly is what enables one engine to be more efficient. For example, one of the easiest ways to get more power is to simply make an engine BIGGER. Of course, that’s what this “cubic inches” and “liters” stuff is all about! More cubic inches or liters of size and the engine can breathe a larger volume of air– so when the (more) air/fuel mixture explodes, there’s more energy (horsepower) produced!
But wait! Bigger means more fuel used, more smog and a higher cost of operation. Right! How about if we can just make smaller engines simply more efficient? Terrific. How do we do it?
Well, if you kept the small engine small and simply increased the number of intake valves (doors) from one to two — and did the same thing for the exhaust valves, you’d have four valves per cylinder instead of two. That would mean that that small engine could breathe a little better — increasing its efficiency — and still be economical.
So there you have it: the multi-valve engine — it means that the engine has got four valves per cylinder instead of the conventional two. And with that, instead of a six-cylinder engine having twelve valves, it will have twenty four valves (six cylinders with four valves each).
While the four-valve-per-cylinder design is not new in the auto industry (world class race and exotic cars have been using this technology for years), you can expect to see more engineering advancements as companies to battle for our new car dollars. Think of the multi-valve engines as one of the newest “differential advantages” when comparison shopping in the showroom. Sort of like the big aviation-style “fins” on fenders of cars in the 1950s … except the best new “21st-century” features are functional.
So where does that leave us to look for what will be on your family sedan in future years? Here’s a hint: Check out today’s Formula One cars; they are the periscopes that allow us to view the future of new-car showroom engineering!
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