Some details of the 2AZ-FE engine
in [Toyota]
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From: Dyno on 17 Jul 2008 00:57 RT wrote: > On Wed, 16 Jul 2008 09:43:13 -0700 (PDT), EdV <systmengr(a)hotmail.com> > wrote: > >> On Jul 15, 11:57 pm, johngd...(a)hotmail.com wrote: >>> Hee hee hee. 2AZFE "an advanced powerplant?" that's a good one. >>> Checkout the Audi FSI 2.0T for an advanced design with a flat torque >>> curve from 2000-5000 RPMs. >>> >> IIRC, The flat torque is because of the CVT transmission design and >> not the engine. I could be wrong. >> . > > A transmission has nothing to do with torque output of an engine. > A CVT is able to keep the rpms at max torque at all times while > accelerating. Max HP speed will give best acceleration.
From: Ray O on 17 Jul 2008 01:02 "Built_Well" <Built_Well_Toyota(a)hotmail.com> wrote in message news:119cdb67-aa9c-4671-8ed9-5bc9699d25d0(a)56g2000hsm.googlegroups.com... > Nate Nagel wrote: >> Built_Well wrote: >> > C. E. White wrote: >> > >> >> EdV wrote: >> >> >> >>> Is the 2AZ-FE considered a direct injectin engine? >> >> >> >>No >> > >> > ============= >> > >> > The 2AZ-FE is a direct injection engine. It does not >> > use a mechanical distributor, and the engine does >> > use a crankshaft sensor and a camshaft sensor, among >> > other things. >> >> "direct injection" typically refers to a very high pressure fuel >> injection system that injects fuel directly into the combustion chamber >> rather than into the intake runner or a throttle body. >> >> What you are describing is a "distributorless ignition." >> >> nate > ============================================ > > Very good information. I enjoyed reading it, and you're > right that the Camry does not inject fuel into the combustion > chamber but into the "antechamber" in the cylinder head that > comes just before the valve. That's what the manual's diagram > seems to show anyway. > > But the 2AZ-FE /is/ a Direct Injection System. Here's a quote > from the Camry's service and repair manual on Page EG-57: > > "A DIS (Direct Ignition System) has been adopted. The DIS improves > the ignition timing accuracy, reduces high-voltage loss, and > enhances the overall reliability of the ignition system by > eliminating the distributor. The DIS in this engine is an > independent ignition system which has one ignition coil (with > igniter) for each cylinder." > As Nate pointed out, you appear to be confusing "injection" with "ignition." Direct injection means that the fuel is injected directly into the combustion chamber, and the cylinder head has another opening for the fuel injector instead of injecting the fuel into the intake runner (what you called the "antechamber." Injecting the fuel directly into the combustion chamber requires much higher pressure to atomize the fuel in the higher pressures within the combustion chamber. Direct ignition has been around for over 15 years. -- Ray O (correct punctuation to reply)
From: Scott Dorsey on 17 Jul 2008 09:14 RT <noyabusiness(a)yahoo.com> wrote: >On Wed, 16 Jul 2008 09:43:13 -0700 (PDT), EdV <systmengr(a)hotmail.com> >wrote: > >>On Jul 15, 11:57 pm, johngd...(a)hotmail.com wrote: >>> Hee hee hee. 2AZFE "an advanced powerplant?" that's a good one. >>> Checkout the Audi FSI 2.0T for an advanced design with a flat torque >>> curve from 2000-5000 RPMs. >>> >>IIRC, The flat torque is because of the CVT transmission design and >>not the engine. I could be wrong. >>. > >A transmission has nothing to do with torque output of an engine. >A CVT is able to keep the rpms at max torque at all times while >accelerating. Right. Correspondingly, if you have a CVT, you can get away with an engine that has high torque in a very narrow speed range, whereas with a conventional transmission the engine has to be able to provide good torque over a wider range of speeds. (ie. the torque curve has to have a much wider peak on it). --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis."
From: EdV on 18 Jul 2008 09:45 This is how I understand GDI (gasoline DIRECT injection), feel free to correct my mistake Fuel and air mixture are injected in some kind of pressure tank where the pressure is increased, by compressing the mixture I suppose. At this stage the ratio of the fuel and air is adjusted for optimum burn. This pressure tank sometimes called as a *common rail*? has a nozzle that will release the pressurized fuel-air mixture directly into the chamber chamber via the intake valves. This high pressure coupled with optimum ratio allows the engine to run more fuel efficiently and, of course, more powerful. The VVTi (toyota) will then adjust the opening of the valves whether to inject the mixture during the intake stroke or slightly delayed.
From: C. E. White on 18 Jul 2008 11:05
"EdV" <systmengr(a)hotmail.com> wrote in message news:2e0036d7-156b-4b0e-9625-11ef7fab6a74(a)i36g2000prf.googlegroups.com... > This is how I understand GDI (gasoline DIRECT injection), feel free > to > correct my mistake > > Fuel and air mixture are injected in some kind of pressure tank > where > the pressure is increased, by compressing the mixture I suppose. At > this stage the ratio of the fuel and air is adjusted for optimum > burn. > > This pressure tank sometimes called as a *common rail*? has a nozzle > that will release the pressurized fuel-air mixture directly into the > chamber chamber via the intake valves. This high pressure coupled > with > optimum ratio allows the engine to run more fuel efficiently and, of > course, more powerful. The VVTi (toyota) will then adjust the > opening > of the valves whether to inject the mixture during the intake stroke > or slightly delayed. In the direct engine engines I have researched, there is no tank that mixes the fuel and air. There is an injector in the combustion chamber instead of in the intake tract before the intake valves. Air is admitted into the combustion chamber by the valves. Fuel is injected directly into the combustion chamber, instead of being mixed with the air in the intake tract before the intake valves. By injecting the fuel directly into the combustion chamber, you can create a "stratified charge." In other words a non-uniform mixture of gasoline vapor and air. Gasoline is very difficult to ignite if you don't have the proper air/fuel mixture. By creating a stratified charge, you can have a proper A/F mixture in the area of the spark plug and a lean mixture everywhere else. The spark plug can then easily ignite the proper mixture in the area of the spark plug and this in turn will burn the leaner mixture elsewhere in the combustion chamber. This allows an overall leaner mixture to be burned, resulting in higher efficiency. Chrysler tried this years ago with carbureted engines with limited success (tried to manipulate the mixture with combustion chamber and intact tract shape). Honda tried something a little different with a three valve design in the late 70's (two "regular" valves and one smaller valve to richen the mixture near the plug). Neither worked very well. There are a lot of great claims being made for direct injection engines. However, the direct injected manual transmission Mazda 5 gets worse EPA gas mileage than the regular old 4 cylinder automatic Toyota RAV4 (which is larger and heavier...). Ed |