Mazda’s hotly anticipated SKYACTIV-X Spark Controlled Compression Ignition engine has been described as the “Holy Grail” of gasoline motors—something with. Housing in the Santa Clara region of California is insanely expensive. Tech companies have taken to building modern day versions of mill towns just so their employees. Six people from Santa Clara, California have been arrested and charged with selling arcade cabinets full of “counterfeit games”, which they are alleged to have.Apple Cider Vinegar Isn't the Miracle Elixir It's Cracked Up to Be. Apple cider vinegar has been a multipurpose folk remedy for decades, touted as a disinfectant, a natural way to replenish skin and hair, and a superfood with all kinds of benefits. Science has backed a few of these purposes, for vinegar in general, but the observable results are pretty meh. Don’t Expect Apple Cider Vinegar to Do Anything for Your Skin and Hair. Several natural living and homeopathic beauty sites tout the benefits of apple cider vinegar to renew the appearance of skin and hair. Some people from a medical background recommend it. I have personally incorporated apple cider vinegar into my daily diet and skincare routine and have seen firsthand the benefits of doing so,” says Rebecca Lee, a registered nurse and founder of the natural health website, Remedies. For. Me. com. But there is no definitive study on how well apple cider vinegar performs at skin and hair cleansing tasks. Cosmetic chemist Randy Schueller is skeptical. T]he benefits of ACV on hair or skin are largely exaggerated,” he says. Vinegar has a low p. H which is non- damaging but other than helping to remove mineral buildup, vinegar doesn’t really provide any benefit.” And the idea it makes hair shinier, he says, “is just a myth.”Vinegar Can Kill Bacteria, but It’s No Substitute for Lysol. Vinegar has been used as a disinfectant since the time of Hippocrates, Greek granddaddy of medicine, who prescribed it for ulcerations and sores. The stuff really does kill bacteria, which is why it’s a great choice for washing lettuce. But it’s been a long time since vinegar was your best germ- killing option for most purposes. For example, in one study, chemical disinfectants like Clorox and Lysol handily outperformed vinegar in reducing pathogens. Medical professionals generally agree that modern chemicals are better at cleaning wounds and fighting infection. It’s Not a Miracle Weight Loss Tonic, Either. If you’re a mouse, good news: Experiments have shown that vinegar helps mice burn fat and suppresses their appetite (by, uh, making them nauseous). There is one solid, large study of vinegar’s effects on humans, published in 2. Japanese researchers. Subjects considered “obese” by Japanese standards (not the less stringent standards of the country that invented the Denny’s Grand Slam) were divided into three groups and given a drink containing one tablespoon of vinegar, two tablespoons of vinegar, or a placebo. All of the vinegar sippers lost more weight than the placebo drinkers. How much weight? A mere two to three pounds over 1. So, even if it helps, we’re not looking at the secret to major weight loss. Adding vinegar to a meal has also been shown to lower a person’s glycemic response to that meal, making it a useful tool in managing diabetes. You can take advantage by using a vinegar- based salad dressing or adding an acetic element, like vinegar or a pickled vegetable, to Japanese- style rice. Vinegar has also been shown to limit the post- meal blood- sugar reaction in people with type- 2 diabetes.“Everyone has an explanation on how this works,” says David Greuner, MD, of NYC Surgical Associates. The exact mechanism is not precisely known, but acetic properties and antioxidants, both of which apple cider vinegar provides, are known to absorb or balance out the effects of sugar, he says. So some science backs the apple cider vinegar folklore, but there’s no reason to be as excited about it as Dr. Axe. Also, vinegar is not without its downsides, doctors warn. Its acidic qualities can damage teeth, hurt throats, upsets stomachs and lower potassium levels. And it tastes like, well, vinegar. Mazda’s ‘Holy Grail’ Of Gasoline Engines Is Completely Fascinating. Mazda’s hotly anticipated SKYACTIV- X Spark Controlled Compression Ignition engine has been described as the “Holy Grail” of gasoline motors—something with diesel- like fuel economy, but far better efficiency. I went to Germany to talk to Mazda’s extremely nerdy engineers, and before I actually drove the thing, here’s what I learned.(Full Disclosure: Mazda wanted me to drive their SKYACTIV- X prototype, so the company flew me to Frankfurt, Germany, put a nice roof over my head, and fed me delicious foods whose names had more umlauts and Scharfes S’s than I could count.)Mazda brought executive officers, VPs and managers from its powertrain, vehicle development, and research and development teams to explain to journalists how the SKYACTIV- X Spark Controlled Compression Ignition engine works, and why it matters. In addition, Mazda discussed its all- new platform, which is where we’ll start before jumping into the exciting SPCCI engine goodness. The New Platform. Despite having driven some prototype next- generation Mazda. Frankfurt, I can’t really say much about its improvement over the outgoing bones. But the main points executive manager of vehicle development Hiroyuki Matsumoto stressed when talking about the new structure dealt with refinement. Matsumoto said that, in its effort to improve a driving feeling they call Jinba Ittai (“Connection between horse and rider”), the company studied the human gait to establish a “platform that optimizes human ability to balance.”Part of that involved designing the seat supports to “maintain natural S- curve of the spinal column by the erection of the driver’s pelvis” (you can see that below). Mazda also designed a new seat structure that’s apparently able to quickly and “smoothly transmit the energy input from vehicle body to the driver’s pelvis.”On top of that, Matsumoto told journalists that the body has been stiffened to reduce the transient response time between the input load on one damper, and the response load at the damper in the opposite corner. Mazda does this by using what it calls “ring structures” (shown in the dotted green circles below): The engineer also mentioned suspension and tire changes aimed at smoothly controlling energy transfer from the wheel to the body, as well as NVH changes like the 1. Ultimately, Mazda’s main points when discussing the new platform seemed to revolve around driver comfort, with emphasis on ride quality, noise, and the way the car communicates inputs to the driver’s ass. Unfortunately, I didn’t spend enough time in the prototype to really assess how much better this platform is than the last. We’ll have to wait for a long- term test for that. The Benefits Of Compression Ignition. To understand the whole point behind Mazda’s new gasoline compression engine tech, let’s look at the seven factors the company works on to increase internal combustion engine efficiency (shown on the left of the graphic below). They are: compression ratio, specific heat ratio, combustion period, combustion timing, heat transfer to the wall, differential pressure between intake and exhaust, and mechanical friction. Improving these attributes theoretically leads towards the “ideal” internal combustion engine, and SKYACTIV- X takes a number of steps in the right direction. Higher Compression Ratio And Specific Heat Ratio. Mazda mentions in its presentation that combustion engine efficiency is related to compression ratio and the intake charge’s specific heat ratio via the equation above. In other words, cranking up compression ratio and specific heat ratios yields better efficiency. SKYACTIV- G, Mazda’s current generation of gasoline engine technology, used a clever exhaust system, a piston cavity, and a high- pressure fuel system with multi- hole injectors to prevent knocking and to allow for a ridiculously high 1. SKYACTIV- X, a compression ignition engine, cranks that figure up to between 1. As for bumping up that specific heat ratio (“k”) value, Mazda says running the engine lean and decreasing its combustion temperature takes care of that. We know that k for air is about 1. That means the more air you can put into that air: fuel charge, the higher that overall k value, and thus the greater the efficiency. Decreased combustion temperatures are a result of lean burn (and indeed, why NOx emissions are so low for this type of engine). The benefit, Mazda shows in the plot above, is that the lower combustion temperatures mean less energy is lost “to molecular vibrations and decomposition.” Thus, a lower combustion temperature yields a higher k, which—again—means better efficiency. Combustion Period And Timing. Aside from the higher compression ratio and specific heat ratio it allows, compression ignition engines tend to burn their lean mixtures thoroughly and rapidly. This means energy from combustion can be more efficiently translated into work done on the piston, whereas spark ignition engines tend to involve a significant time delay associated with flame propagation. Pumping Losses And Heat Loss Through Cylinders. The other two areas where a lean compression engine can yield significant efficiency benefits is in cooling losses and throttling losses. The first is fairly straightforward, as lower combustion temperatures mean less heat transferred to the cylinder walls. The second has to do with the fact that a leaner air/fuel mixture means there’s more air required for a given torque level. This—along with strategic use of EGR, variable valve timing and a supercharger to control airflow into the cylinder— means the throttle plate can be held fully open more often than on a standard gasoline engine. So instead of trying to suck air through a restrictive throttle plate, air can flow easily into the cylinders. Mazda says this also has the added benefit of improved throttle response, since there’s no longer a delay in trying to fill the intake plenum. Emissions. Mazda’s new technology also promises reduced emissions, which is a big deal, since Dieselgate is putting a huge damper on compression engines. With internal combustion engines, oxides of nitrogen tend to rise with a higher air: fuel ratio up to a point. Above that point, NOx output drops (as you can see from this plot). Since Mazda’s new engine usually runs at a lambda (fuel: air ratio relative to stoichiometric) of at least 1. NOx output is rather low, and can therefore forgo expensive emissions equipment. Carbon emissions, too, are reduced with SPCCI due to its higher fuel efficiency. How Mazda’s SPCCI System Works, Exactly. A gasoline compression ignition engine isn’t exactly a new concept. In fact, if you go back an entire decade, you’ll see that General Motors even had prototype Homogeneous Charge Compression Ignition engines (with spark assist) ready for journalists to drive around the test track. Why, then, is everyone getting excited about Mazda’s gasoline compression engine when we’ve been hearing about similar technologies for years? The answer comes down to how Mazda’s controlling combustion. The two main issues that Mazda says have impeded the proliferation of gasoline compression engines are: 1. The limited zone in which compression ignition is possible and 2. The rough transition between compression and spark ignition. What Mazda has done to solve these problems is devise a system called Spark Controlled Compression Ignition, SPCCI, a strategy in which a spark plug creates a “fire ball,” which acts to compress the homogeneous mixture of air/inert EGR gases and fuel to incite compression ignition. Here’s another look from the top of the cylinder look: The spark plug itself isn’t able to create this fireball with a lean mixture. So what Mazda has done is positioned a fuel injector close to the plug. That high- pressure injector initially shoots small amounts of fuel into the cylinder during the intake stroke. That fuel mixes with a cyclone of air from the intake (which is fed from a supercharger and cooled EGR—both of which can be precisely controlled) to create a homogeneous lean mixture around the periphery. During the compression stroke, a certain amount of fuel is injected into the “eye” of the lean vortex (an amount based on engine load), and spark is precisely timed to light the rich fireball, which then ignites the lean mixture around it—and voila!
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