Re: Some details of the 2AZ-FE engine

On Jul 14, 11:34 pm, "Ed White" <[email protected]> wrote:
> "Built_Well" <[email protected]> wrote in message
>
> news:97101848-da38-42b3-88d7-6dcb0def23b9@s50g2000hsb.googlegroups.com...
>
>
>
> > 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)
>
> Advanced, in what way? Lots of comparable engines from many manufacturers. I
> have a hard time thinking of any engine that requires routine valve
> adjustment as "advanced." But I guess that is also a trend these days. And
> since most people ignore the routine valve clearance checks, I guess it is
> irrelevant. 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).
>
> > is the same engine that was used in the '01 Highlander SUV.
> > 5th Generation Camrys cover Model Years '02 - '06.
>
> It is still used today in Camrys, RAV4s, and ?
>
>
>
> > 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."
>
> > The cylinder head cover (not to be confused with the cylinder
> > head) is made of magnesium alloy for lighter weight. I think
> > cylinder head cover is synonymous with "valve cover," but the
> > Camry manual refers to it as the "cylinder head cover."
>
> > Since the manual doesn't mention what the cylinder head, itself,
> > is made of, I will assume iron, but just an assumption.
>
> Nope, it is aluminum.
>
> > The cylinder head gasket, used between the aluminum engine block
> > and the (iron?) cylinder head is a steel-laminate type of
> > material. Any concern about electrolysis taking place between
> > the steel-laminate and aluminum?
>
> Nope, but be sure to use the recommended coolant.
>
> > When the service and repair manual says the dry weight of the
> > engine is 267 pounds, does that include the crankcase, crank,
> > cylinder head, and valve head with camshafts--or does the
> > weight only include the engine block without crankcase
> > and cyclinder head, etc.?
>
> Everything that makes up the main engine assembly (block, pistons, heads,
> cams, etc.) but no oil or water. Probably does not include accesorries
> (alternator, starter). May or may not include intake system. Probably
> includes intake to the throttle body.
>
> > The crankshaft and camshafts are connected by a timing chain,
> > not a belt.
>
> Common practice these days. Cam belts are mostly on the way out for modern
> engines.
>
> > The oil pump is located behind the timing chain cover at the
> > front bottom of the engine, even lower than the crankshaft. The oil
> > pump has its own short section of chain that's connected to the
> > crankshaft. Couldn't tell from the picture if this is a second,
> > dedicated chain, or just part of the larger chain that ascends to
> > the camshafts.
>
> Completely separate chain (referred to as the No. 2 Chain Sub-assembly).
>
> > Double overhead cams, don't ya know (DOHC) :-)
>
> > If I had to guess, I'd say the oil pump has its own dedicated
> > short chain that's separate from the timing chain, ie., camshaft
> > chain..
>
> Correct.
>
> Ed


Is the 2AZ-FE considered a direct injection engine?

"EdV" <[email protected]> wrote in message
news:8ce8d082-d6c7-4195-992c-2cf1e40b68cb@59g2000hsb.googlegroups.com...

> Is the 2AZ-FE considered a direct injection engine?

No.

Ed

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.

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

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

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."

Also, the book "Auto Upkeep" says, "Some manufacturers call the
distributor-less ignition system a direct ignition system."

Maybe there are two sides with an honest difference of opinion?
Sorta like how API Group III oils are considered synthetic in
the U.S.A., but not in Europe.

However, the book says there are 3 types of ignition systems:

Conventional, Electronic, and Distributor-less.

The web site ProCarCare.com doesn't mention firing into the
combustion chamber as a pre-requisite for D.I.S.

Here's a quote:

The Direct Ignition System (DIS) uses either a magnetic crankshaft
sensor, camshaft position sensor, or both, to determine crankshaft
position and engine speed. This signal is sent to the ignition
control module or engine control module which then energizes the
appropriate coil.

You obviously know a whole lot more about cars than I do, but the
2AZ-FE does seem to be a Direct Ignition System.

Here's a link to the ProCarCare site with the info:

http://www.procarcare.com/icarumba/resourcecenter/encyclopedia/icar_resourcecenter_encyclopedia_ignition.asp

Britannica Online seems to agree:

direct-ignition system, or distributor-less ignition system
(engineering):

description and use:

Many automobile engines now use a distributor-less ignition
system, or direct-ignition system, in which a high-voltage pulse
is directly applied to coils that sit on top of the spark plugs
(known as coil-on-plug). The major components of these systems
are a coil pack, an ignition module, a crankshaft reluctor ring,
a magnetic sensor, and an electronic control module.

>From Wikipedia's entry on Ignition System:

Other systems dispense with the distributor and coil and use
special spark plugs which each contain their own coil
(Direct Ignition). This means high voltages are not routed all
over the engine, but are instead created at the point at which
they are needed. Such designs offer potentially much greater
reliability than conventional arrangements.

A site devoted to the Honda Insight says this:

The Insight engine employs a direct ignition system similar to
those used on the Honda S2000 and the 1999 Odyssey. Separate
ignition coils for each cylinder are located directly above
the spark plugs.