Some details of the 2AZ-FE engine
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From: Leftie on 22 Jul 2008 00:30 Retired VIP wrote: > On Mon, 21 Jul 2008 06:35:30 -0700 (PDT), EdV <systmengr(a)hotmail.com> > wrote: > >> On Jul 18, 2:16 pm, Retired VIP <jackj.extradots....(a)windstream.net> >> wrote: >>> On Fri, 18 Jul 2008 08:36:01 -0700 (PDT), EdV <systme...(a)hotmail.com> >>> wrote: >>> >>>> On Jul 18, 11:05 am, "C. E. White" <cewhi...(a)removemindspring.com> >>>> wrote: >>>> There is an injector in the combustion chamber >>> Direct injection allows placing a rich fuel/air mixture around the >>> sparkplug and a much leaner mixture in the rest of the cylinder. By >>> the time the flame front moves out to the rest of the cylinder, the >>> piston has moved past top dead center and the much faster burn rate of >>> a lean mixture won't hurt the engine. >>> >>> I hope this helps and if I've gotten anything wrong in this, I'm sure >>> someone will correct me. >>> >>> Jack >> Great! So this means its possible not to have VVTi and Direct >> injection at the same time. The timing of the fuel comes from the >> nozzle and not from the opening of the valves, although air enters >> through the valves, its the fuel which is controlled and not the air. > > No, I think it would still be possible to use variable valve timing > and direct injection at the same time. The amount of fuel is > controlled by the engine computer based on info it gets from the O2 > sensor, throttle position, RPM, etc. VVTi would still be a valid way > to increase engine efficiency by controlling the amount of air, that's > really all it controls with multi-port injection also. > > Jack I think you misread the post. He was saying it's possible to not have both features, not that it's impossible to have both.
From: Retired VIP on 22 Jul 2008 09:16 On Mon, 21 Jul 2008 23:30:03 -0500, Leftie <No(a)Thanks.net> wrote: >Retired VIP wrote: >> On Mon, 21 Jul 2008 06:35:30 -0700 (PDT), EdV <systmengr(a)hotmail.com> >> wrote: >> >>> On Jul 18, 2:16 pm, Retired VIP <jackj.extradots....(a)windstream.net> >>> wrote: >>>> On Fri, 18 Jul 2008 08:36:01 -0700 (PDT), EdV <systme...(a)hotmail.com> >>>> wrote: >>>> >>>>> On Jul 18, 11:05 am, "C. E. White" <cewhi...(a)removemindspring.com> >>>>> wrote: >>>>> There is an injector in the combustion chamber >>>> Direct injection allows placing a rich fuel/air mixture around the >>>> sparkplug and a much leaner mixture in the rest of the cylinder. By >>>> the time the flame front moves out to the rest of the cylinder, the >>>> piston has moved past top dead center and the much faster burn rate of >>>> a lean mixture won't hurt the engine. >>>> >>>> I hope this helps and if I've gotten anything wrong in this, I'm sure >>>> someone will correct me. >>>> >>>> Jack >>> Great! So this means its possible not to have VVTi and Direct >>> injection at the same time. The timing of the fuel comes from the >>> nozzle and not from the opening of the valves, although air enters >>> through the valves, its the fuel which is controlled and not the air. >> >> No, I think it would still be possible to use variable valve timing >> and direct injection at the same time. The amount of fuel is >> controlled by the engine computer based on info it gets from the O2 >> sensor, throttle position, RPM, etc. VVTi would still be a valid way >> to increase engine efficiency by controlling the amount of air, that's >> really all it controls with multi-port injection also. >> >> Jack > > I think you misread the post. He was saying it's possible to not >have both features, not that it's impossible to have both. You are right lefty. I did misread the OP's comments. Sorry and he would be right. I guess I get in too much of a hurry sometimes. Jack
From: Leftie on 23 Jul 2008 07:24 Retired VIP wrote: > On Mon, 21 Jul 2008 23:30:03 -0500, Leftie <No(a)Thanks.net> wrote: > >> Retired VIP wrote: >>> On Mon, 21 Jul 2008 06:35:30 -0700 (PDT), EdV <systmengr(a)hotmail.com> >>> wrote: >>> >>>> On Jul 18, 2:16 pm, Retired VIP <jackj.extradots....(a)windstream.net> >>>> wrote: >>>>> On Fri, 18 Jul 2008 08:36:01 -0700 (PDT), EdV <systme...(a)hotmail.com> >>>>> wrote: >>>>> >>>>>> On Jul 18, 11:05 am, "C. E. White" <cewhi...(a)removemindspring.com> >>>>>> wrote: >>>>>> There is an injector in the combustion chamber >>>>> Direct injection allows placing a rich fuel/air mixture around the >>>>> sparkplug and a much leaner mixture in the rest of the cylinder. By >>>>> the time the flame front moves out to the rest of the cylinder, the >>>>> piston has moved past top dead center and the much faster burn rate of >>>>> a lean mixture won't hurt the engine. >>>>> >>>>> I hope this helps and if I've gotten anything wrong in this, I'm sure >>>>> someone will correct me. >>>>> >>>>> Jack >>>> Great! So this means its possible not to have VVTi and Direct >>>> injection at the same time. The timing of the fuel comes from the >>>> nozzle and not from the opening of the valves, although air enters >>>> through the valves, its the fuel which is controlled and not the air. >>> No, I think it would still be possible to use variable valve timing >>> and direct injection at the same time. The amount of fuel is >>> controlled by the engine computer based on info it gets from the O2 >>> sensor, throttle position, RPM, etc. VVTi would still be a valid way >>> to increase engine efficiency by controlling the amount of air, that's >>> really all it controls with multi-port injection also. >>> >>> Jack >> I think you misread the post. He was saying it's possible to not >> have both features, not that it's impossible to have both. > > You are right lefty. I did misread the OP's comments. Sorry and he > would be right. I guess I get in too much of a hurry sometimes. > > Jack We all do that. The internet seems to induce a kind of Adult ADD - we go too fast when reading and responding...
From: Steve on 23 Jul 2008 16:01 Built_Well wrote: > Gonna write this stuff down and post it so I don't lose it. Had > to wade through a lot of pages to find it. The 5th Generation Camry's > 2AZ-FE engine (an advanced powerplant, by the way) is > the same engine that was used in the '01 Highlander SUV. > 5th Generation Camrys cover Model Years '02 - '06. > > The cylinder block is made of aluminum alloy. It uses aluminum > pistons, high-strength steel connecting rods and caps, forged steel > crankshaft, and, IIRC aluminum camshafts. The VVT-i only works > on the intake camshaft, not the exhaust camshaft. It varies > the timing of the intake valves. There are two intake valves per > cylinder and two exhaust valves per cylinder. Having two of > each increases the total port area, so more air can flow into > and out of the combustion chamber. As the manual's authors > write, "Intake and exhaust efficiency has been increased due > to the larger total port areas." Advanced? Its an average modern v6. Apart from VVT, there's not a damn thing to distinguish it from any other (and most others have VVT these days, so even that's not distinguishing- some have VVT and cylinder deactivation). And if the hear really were iron, then it would be exactly as advanced as the 1962 die-cast aluminum block/iron head slant-6.
From: Steve on 23 Jul 2008 16:06
C. E. White wrote: > > "larry moe 'n curly" <larrymoencurly(a)my-deja.com> wrote in message > news:a197d3c0-d203-4aee-b23a-aaf08ef2c08a(a)56g2000hsm.googlegroups.com... >> >> >> Ed White wrote: >> >>> I was shocked when I found out my Nissan Frontier requires valve >>> adjustment. You have to love the chutzpa of the Nissan engineers. The >>> engine >>> in my Frontier requires valve adjustment only when the valve noise is >>> objectionable. It is going to be damn loud before I'll spend hundreds >>> (maybe >>> thousands) to have the valves adjusted. I assume the engineers at Nissan >>> (and Toyota) have designed the valve system so that the valve clearance >>> increases with wear - else you run the risk of burning valves if the >>> clearance goes too low (learned from sad experience on older engines). >> >> I have a 1998 with KA24DE engine. How can a valve adjustment with >> this type of engine be so expensive? Are they charging that much for >> the shim disks? > > I have the V6 in my Frontier. To replace the shims you have to remove > the cams - 4 of them. Hopefully I'll never need to have it done. I guess > things are much better now. Years ago I had a Jensen-Healey with a DOHC > 4 cylinder engine. Adjusting the valves was a nightmare - but still > easier than for the Frontier V-6. > > Ed Shims-in-a-bucket cam followers for valve adjustment is positively stone-age (the last car I had so-equipped was a '78 Plymouth Horizon with the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters that are common now don't carry enough mass penalty to worry about and are commonly used in engines with 7500+ RPM redlines. That said, I never had to adjust the valves on that VW engine either. Everything else about it sucked, but the valves never needed adjustment! ;P |