Comments by "afcgeo" (@afcgeo882) on "Engineering Explained" channel.

In DI/PI engines, port injectors are used at start-up and at low RPMs when efficiency isn’t needed, switching over to direct injection at higher RPMs to produce more power. This not only reduces carbon build-up on intakes by pouring gasoline on them, but also ensures that direct injection isn’t used at low temperatures. That reduces unburned fuel (soot) and oil dilution. The trade-off is that these engines are quite a bit more complex in fuel injection and pumps, but also in timing and programming.
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@Scoots1994 Quite the opposite. Direct injection is very happy at high RPMs and can easily “keep up”. Valves also don’t need cooling. “How It Works According to Toyota, during low-to-medium engine loads, both direct-type and port-type fuel injection are used together, or one of them is used to create homogeneous mixed air and fuel, thus contributing to stable combustion processes. During high engine load ranges, only the direct-type fuel injection is used to cool down the intake air with the chilling effect of vapors in the fuel, which is injected into the cylinder, improving charge efficiency and anti-knock properties. Under some conditions, the intake valves open to allow the homogeneous air/fuel mixture into the combustion chamber, and fuel is injected during the first half of the intake stroke. During a cold start, the system times the opening of the port and direct fuel injector to decrease emissions and achieve stratified combustion. Immediately after a cold engine start and during the exhaust stroke, fuel is injected into the intake port from the fuel injector assembly (for port injection). Fuel is also injected from the direct fuel injector near the end of the compression stroke. This results in an air-fuel mixture that is stratified, and the area near the spark plug is richer than the rest of the air/fuel mixture. This process allows a retarded ignition timing to be used, raising the exhaust gas temperature. The increased exhaust gas temperatures promote rapid warmup of the catalysts and improve exhaust emission performance. It is impossible to detect where the changeover from port to direct injection occurs. The only way to see the different fuel injection operations is with a scan tool.” “Tomorrow’s Tech” article from their website, March 21, 2019.
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Your 13 year old Subaru in fact does have a better system because it is a much more expensive car. The non-R Legacies don't have such great systems. It's all an issue of cost savings. Does your car have a physical limited slip differential or is it electronic (which is really just a traction control system.) It seems you use a ton of Subaru terminology, but not really sure of what they do. The Vehicle Dynamics Control system is simply a traction control system integrated into turns. It is now called Torque Vectoring, but is really just active traction control. Acura is the only company that employs actual torque vectoring where they alter the amount of torque sent to each wheel in turns by adding torque. What sets your Subaru from today's systems is the 80:20 differential. Today's Subaru's mostly give you a 40:60 to 60:40 split. Too bad people today don't know that and think they're still getting something good. They aren't anymore.
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@BigEightiesNewWave Does it matter in the context? We all know it’s sprayed, so are you simply being pedantic because you have nothing of substance to contribute to the conversation? Obviously yes.
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You certainly can, one day, when you find something wrong with it.
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You didn't see many 18-wheelers using automatic transmissions until recently because people thought they would break, but they aren't breaking and they're being adopted all over. One of the real reasons is that a manual transmission gives you a choice to skip gears or start in a gear higher than 1st, depending on the weight of the cargo and whether you're going up an incline, level or down an incline. A CVT would need to be properly programmed and it would need a heavy duty metal belt to drive the system, but it can be done. It's just much more expensive right now. How do you think Diesel trains operate?
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ALL transmissions are "friction type", whatever that means. Do you know how Diesel trains work?
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There is no such concept as part-time or full-time AWD. These concepts were developed for 4WD systems, not AWD. All AWD are full-time as they are regulated by the computer at all times. Their torque splits may be varied, even to 0 to an axle, if that's what's best at times, but the system is on 100% of the time. Part-time 4WD systems required the driver to manually engage the system for it to work. Full-time systems were always on.
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It's a play on words on people who drive Subarus. The play uses Scooby Doo and Subaru.
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@therealjpow actually, every single test out there shows the 0-60 slightly faster on the CVT than the manual. It makes sense too, because the CVT keeps the turbo boost and the torque at their peak RPMs for as long as the throttle is open all the way, while with a manual, both keep going in and out of the peak band, RPMs being either too high or too low.
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Why would you comment on a video without watching it? It explains E-CVTs perfectly!
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Or… just buy a dual injection engine.
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How does the Subaru Crosstrek handle anything? Answer: Very slowly.
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@Montblanc1986 Someone didn’t watch the video!
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@1989rs500 I don’t know of anyone who had thought it would be a disaster. It’s just fuel injectors.
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@1989rs500 People are still doing that. They’re (people) generally adverse to change. We’re also talking about Ford F150 customers, most of whom are… how should I say this… lower on the intellectual spectrum.
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@1989rs500 That’s for a good reason. Almost all the engines available are turbo and the V8 option is very expensive. They were forced into change.
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@rars0n I think you need to read what you wrote because you’re now contradicting yourself. The VW EA888 Gen 3 engine (in Europe) is a DI engine with supplementary port injectors that it uses under low loads. That is to say it always injects via direct, but splits the injection duties with port injectors under cold start and low RPM loads. This was to reduce particulates in the exhaust to meet Euro 6 standards without a particulate filter. The VW gen 4 EA888 went back to DI only.
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You have the exact same system in all of your cars, bud. Only the CVT equipped Foresters have active torque vectoring, not the manual ones. The center diff lockers are only present on the Impreza WRX STi, not the regular Impreza. What newer cars have is better traction control systems, which can account for some better handling and added traction.
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The S-AWC is on the entire CUV line-up now.
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There are actually plenty of vehicles that have a rear bias and vehicles that can create a rear bias. The Ford Kuga/Escape and Jeep Cherokee for example, normally send 100% of torque to the front, but given front slippage, increase the rear torque until either the slippage is gone or they send 100% of torque to the rear. German performance cars like BMW and Mercedes are rear-biased for performance. They only send some torque to the front wheels. They design most of their cars to be RWD, so they want to stay true to that.
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1. The current model CVT Subarus have no locking differentials, so nothing locks. 2. They are only capable of either a 60:40 or up to 40:60 split, depending on the sensor input. 3. X-Mode is a hill descent control and does not control torque split between axles. It only controls torque output through the transmission the way a low gear would, to brake with the engine AND controls the brakes to keep the car rolling at a steady pace down the hill.
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Considering that only the Evolution Lancers have AWD like that, I doubt your hunch is correct. Engineering is a science. Science doesn't approach a subject to satisfy a desire. Science has to be objective. Objectively, there's no way to tell what system is best as they all approach things differently and have their pluses and minuses. To really test which system is best, they'd have to attach each system to the same car and run it on a wide variety of courses, in the same weather, with the same driver and then only look at the test data, not ask the drive of what he liked more. Then you can get the data and determine for yourself what you like most.
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Which system? The CVT goes from 60:40 to 40:60. The manual I believe only moves 5 percent in each direction. I don't know about the WRX or STi.
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For the Outlander?
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@mb14u2c2 There is no CVT STi, but that explains why the service mechanics suck. They don't know their own product.
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ALL WRXs have a limited slip diff in the rear. WRX STi have limited slip diffs in front and rear.
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I believe what he meant was that the CENTER differential was open on the viscous center diff system. Most vehicles that run in a 50/50 torque split have locked differentials. It's important to know that because the open center differential allows for different RPMs between axles.
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Almost correct. X-Drive IS hill descent control and has no benefits for driving on level surfaces or up hill. It is a system to slow your descent without using brakes via your foot. It uses the engine and brakes to slow you to a crawl while descending. It's mostly a gimmick as it rarely needs to be used and in most cases it does, shifting into a low gear will get the job done along with your right foot.
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EcoBoost is simply a Ford brand name for a turbo engine. It provides turbo boost and it's "Eco" because it is supposedly more economical than a naturally aspirated engine of that output (though I'm not sure that's really the case.)
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The CVT is connected to the clutch pack, which is a part of the PTU, which then runs both drive axles. I don't see how the slippage in the clutch pack, which alters the torque distribution between the front and rear drive axles has an effect on the transmission, which simply connects the torque to the PTU. You want to explain your line of thinking?
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The problem is that the manual Subaru system doesn't send all that torque that you think it sends. In fact, it sends up to just 10% extra to either axle, so in fact, it can do either a 60/40 split or a 40/60 split because the viscous coupling never actually activates 100% the way a clutch does. Viscosity thickens, but it never becomes a solid or anywhere close to it.
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You have an older system that was mated to automatic trannies. It was older, but better and could do 20:80 splits if needed.
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@rars0n It’s basically the same, actually. All of them use port injection at low RPMs and direct at high. You just said the same exact thing. Did you read what I’ve said? It’s the same with Ford and Hyundai as well.
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@1989rs500 Ford uses it on 4 different engines, ranging from 2.7L to 5.0. All V6 F-150s have it. It came out on the 3.5 EcoBoost years ago. It just wasn’t reliable. Toyota originally had some issues with the D-4S in the Tacoma too. At this point the technology is well worked out, but long-term maintenance is increased with this, for sure.
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@rars0n The R8 supercar engine developed by Lamborghini uses Port Injection at low DPMs, engaging DI at mid-range RPMs and switching to 85% DI input at high RPMs. However, this engine is basically hand-built for supercar employment, and is one of the most complex engines in the world. It should not be used as a comparison to common car engines. What they’re for, performance-wise is completely different. They operate differently, cost differently and their life expectancy os also very different.
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@rars0n No. Both, the 5.0 and 5.2 were developed by Lamborghini. The 5.0 was sequential injection and the 5.2 is stratified injection. Since 2019 all V10 Lambos use the 5.2. The Lambo 5.2 is used in the R8, RS6, S8 and S6, though the latter two are simplified. Italdesigns cars also use the engine.
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@yolo_burrito I know.
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Yellow and Blue make green. Red and green do not make yellow. Green is NEVER a primary color. ALL color is light. You may be an engineer, but you either don't know much about physics or have forgotten it.
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"Tesla" and "Regret" really go together. They should just rebrand the 3 as the "Regret".
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Unanswered: How much torque can the Active Torque Split (ATS) system send to the front/rear, if needed? This is the most common system and there are no answers anywhere. The only figure ever provided is for the default 60/40 split, but nothing else.
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