Quick quiz on indirect injection diesel

[Ext User(Patrick Young)]

Is the egg shaped/sized precombustion chamber counted
as part of the overall engine capacity?

--

--------------------------------------------
4x4 Hilux Auto Service Centre,
BP 106 Timbuktu,
Mali (West Africa)
Tel: 292 91 52
Specialising in turbo diesel and R290 aircon

[Ext User(Deltic)]

In article <x1ZIe.73170$oJ.15938@news-server.bigpond.net.au>,
Patrick Young <patrick@hilux.ace.unsw.EDU.AU> wrote:

> Is the egg shaped/sized precombustion chamber counted
> as part of the overall engine capacity?

No combustion chamber/precombustion chamber capacity is ever counted for
engine capacity purposes. Only the swept capacity is counted.

[Ext User(veritas)]

Patrick Young wrote:
> Is the egg shaped/sized precombustion chamber counted
> as part of the overall engine capacity?
>
Think of it this way:

Fill the chamber with a fluid (piston at BDC) then rotate the crank to position the piston to TDC, measuring the amount
of fluid that if forced out of the plug-hole = capacity.

IE: stroke x area of piston x n pistons is the engine cubic capacity......

[Ext User(John_H)]

Patrick Young wrote:

>Is the egg shaped/sized precombustion chamber counted
>as part of the overall engine capacity?

Nope. Displacement is calculated from bore and stroke (swept volume).

Combustion chamber volumes (contra or open) are only relevant to
compression ratio -- or is that what you meant to ask?

--
John H

[Ext User(Jim Vatunz)]

On Sat, 06 Aug 2005 17:24:15 +1000, John_H <john4271@hotmail.com>
wrote:

>Patrick Young wrote:
>
>>Is the egg shaped/sized precombustion chamber counted
>>as part of the overall engine capacity?
>
>Nope. Displacement is calculated from bore and stroke (swept volume).
>
>Combustion chamber volumes (contra or open) are only relevant to
>compression ratio -- or is that what you meant to ask?

Just made me think. In the days when engineers considered the metric
system the tool of the devil, how long it would taken them to
calculate capacity?
I suppose mere mortals would never have attempted it in the pre-metric
days.

--
http://members.iinet.net.au/~farmerjim/log/log.html
It's boring but it's something.

[Ext User(John_H)]

Jim Vatunz wrote:
>
>Just made me think. In the days when engineers considered the metric
>system the tool of the devil, how long it would taken them to
>calculate capacity?

Those that did think that way calculated it in cubic inches (pretty
much confined to American designs).

The Brits (who supplied a fair proportion of our cars prior to the
1970's) were always metric orientated when it came to engine
displacement -- in spite of their late adoption of the metric system.
For example, 1920's Bentleys were always designated in litres (or
cc'c) as were most British motorcycles.

The only other designation ever widely used (both here and the UK) was
RAC horsepower ratings, calculated from bore diameter in inches, which
was still used as the basis for registration fees in some Australian
states well into the 1980's. AFAIK Australian manufacturers still
specify RAC horsepower (my VN handbook certainly does)

Science and Engineering in Oz has been taught in metric units since at
least the 1950's, and I think both systems were taught side by side
well prior to then.

--
John H

[Ext User(veritas)]

John_H wrote:
> Jim Vatunz wrote:
>
>>Just made me think. In the days when engineers considered the metric
>>system the tool of the devil, how long it would taken them to
>>calculate capacity?
>
>
> Those that did think that way calculated it in cubic inches (pretty
> much confined to American designs).
>
> The Brits (who supplied a fair proportion of our cars prior to the
> 1970's) were always metric orientated when it came to engine
> displacement -- in spite of their late adoption of the metric system.
> For example, 1920's Bentleys were always designated in litres (or
> cc'c) as were most British motorcycles.
>
> The only other designation ever widely used (both here and the UK) was
> RAC horsepower ratings, calculated from bore diameter in inches, which
> was still used as the basis for registration fees in some Australian
> states well into the 1980's. AFAIK Australian manufacturers still
> specify RAC horsepower (my VN handbook certainly does)
>
> Science and Engineering in Oz has been taught in metric units since at
> least the 1950's, and I think both systems were taught side by side
> well prior to then.
>
> --
> John H

Horse Power = PLANn/33,000

P= working pressure in lb/sq/ft
L= length of stroke in feet
A= area of top of piston in sq inches
N= number of working strokes per minute
n= number of cylinders

Too easy :)

Learnt that (and never forgot it) at Sydney Technical College, Wattle Street, Ultimo (adjacent to the Power House Museum
- which was was working then) just off Harris Street. The skeleton of the building still stands after nearly 50 years
since a fire gutted it (and my bloody cast-iron block that had to be hand chiseled, filed and scraped to some
unreachable tolerance).

[Ext User(John_H)]

veritas wrote:

>John_H wrote:
>>
>> The only other designation ever widely used (both here and the UK) was
>> RAC horsepower ratings, calculated from bore diameter in inches, which
>> was still used as the basis for registration fees in some Australian
>> states well into the 1980's. AFAIK Australian manufacturers still
>> specify RAC horsepower (my VN handbook certainly does)

>
>Horse Power = PLANn/33,000
>
>P= working pressure in lb/sq/ft
>L= length of stroke in feet
>A= area of top of piston in sq inches
>N= number of working strokes per minute
>n= number of cylinders
>
>Too easy :)

As determined by James Watt, relative to steam engines -- also
applicable to internal combustion engines in that bmep (brake mean
effective pressure) replaces P to calculate bhp (brake horse power).
Mostly the calculation has always been done backwards for internal
combustion engines (ie bmep is a derived value), since the Prony brake
(the first dynamometer, invented by Gaspard De Prony around the
1820's) has always been able to measure bhp directly.

RAC ratings were somewhat simpler... bore (in inches) squared, divided
by 2.5, multiplied by the number of cylinders -- which gave an
approximation to bhp in the year 1916 or thereabouts (when the formula
was established). A lot of British cars subsequently used both... for
example, the Morris 8/40 was 8 hp (RAC), 40 bhp (rounded upwards).
Registration was based on the former, hence the reason to emphasise it
and exaggerate the latter.

Early Holdens with a 3" bore were rated as 21.6 hp (RAC) and the
registration costs here in Oz were calculated accordingly. AFAIK
Holden never claimed an exact bhp, which was around 60.
The common system used in Oz was PW (power weight) -- rated
horsepower plus kerb weight in cwt (hundredweight).

One of the consequences of the RAC system was engines that were
ridiculously under square -- ie the stroke was much greater than the
bore. Similarly in Europe, it was registration costs based on
capacity that inspired the development of the early turbo designs (eg
the Saab 99).

--
John H

[Ext User(Jim Vatunz)]

On Sat, 06 Aug 2005 18:53:32 +1000, John_H <john4271@hotmail.com>
wrote:

>Jim Vatunz wrote:
>>
>>Just made me think. In the days when engineers considered the metric
>>system the tool of the devil, how long it would taken them to
>>calculate capacity?
>
>Those that did think that way calculated it in cubic inches (pretty
>much confined to American designs).
>
>The Brits (who supplied a fair proportion of our cars prior to the
>1970's) were always metric orientated when it came to engine
>displacement -- in spite of their late adoption of the metric system.
>For example, 1920's Bentleys were always designated in litres (or
>cc'c) as were most British motorcycles.
>
>The only other designation ever widely used (both here and the UK) was
>RAC horsepower ratings, calculated from bore diameter in inches, which
>was still used as the basis for registration fees in some Australian
>states well into the 1980's. AFAIK Australian manufacturers still
>specify RAC horsepower (my VN handbook certainly does)
>
>Science and Engineering in Oz has been taught in metric units since at
>least the 1950's, and I think both systems were taught side by side
>well prior to then.

Live and learn.
You've got to wonder then if the automotive engineers were switched on
enough to at least measure bores, strokes and capacity in metric that
they as a country still haven't adopted to SI units despite agreeing
to in 1964 (which of course meant that we HAD to go metric since we
were still British then).
Come to think of it if they hadn't decided to change in 1964 then we
may still be using £sd. Now that would be a nightmare.

--
http://members.iinet.net.au/~farmerjim/log/log.html
It's boring but it's something.

[Ext User(Hotman Paris Hutapea)]

On Sat, 06 Aug 2005 09:21:36 GMT, veritas <veritas@coldmail.com>
wrote:

>Too easy :)
>
>Learnt that (and never forgot it) at Sydney Technical College, Wattle Street, Ultimo (adjacent to the Power House Museum
>- which was was working then) just off Harris Street. The skeleton of the building still stands after nearly 50 years
>since a fire gutted it (and my bloody cast-iron block that had to be hand chiseled, filed and scraped to some
>unreachable tolerance).

force on piston = integral of P with respect to Volume

triple integrate over
-stroke length,
-thoeta (angle made by point at which P is taken on bore cross-section
to arbitrary 0 angle),
-and radius.

integral function is P x (pi x R-squared)

you then determine the torque on the cranshaft by throwing in a fudge
factor (function) based on leverage of conrod/crank arm which you can
work into the original triple integral (substitute variable for stroke
position with function that includes fudge factor).

the integral then yields torque x angle (360 deg. if calculated over
one rev). divide by time (rpm) to yield power. multiply by no. of
cylinders.

--

Attorney at Law
5/37 Paknabiel Way
Denpasar, Indonesia.

[Ext User(John_H)]

Hotman Paris Hutapea wrote:
>
>force on piston = integral of P with respect to Volume
>
>triple integrate over
>-stroke length,
>-thoeta (angle made by point at which P is taken on bore cross-section
>to arbitrary 0 angle),
>-and radius.
>
>integral function is P x (pi x R-squared)
>
>you then determine the torque on the cranshaft by throwing in a fudge
>factor (function) based on leverage of conrod/crank arm which you can
>work into the original triple integral (substitute variable for stroke
>position with function that includes fudge factor).
>
>the integral then yields torque x angle (360 deg. if calculated over
>one rev). divide by time (rpm) to yield power. multiply by no. of
>cylinders.

Shit easy when there's a pressure gauge on top of the boiler!

Nor do you need worry about the fudge factor when the conrods are two
metres long.... There's also losses due to friction -- which is
hardly worth bothering about when it's all driven by steam.

No one ever measures cylinder pressure in an internal combustion
enginewhich, unlike steam, isn't a constant anyway. Piston pressure
is always calculated from measured peak torque (and the fudge factor
ignored) -- merely to demonstrate it's place in basic engine theory.
For all other practical purposes it means SFA.

In other words... m.e.p.p. (mean effective piston pressure) is always
a hypothetical quantity.

--
John H