Water Injection Pump 1
I read your article on water injection. I have a
question, I looked around here locally and most pumps mentioned they are
vibratory pumps. Should I try this or keep looking. The price wasn't bad, I
enclosed a link of the pump I'm looking at purchasing. http://www.chriscoffee.com/products/home/repairparts
The pump you have cited looks fine.
Water Injection Pump 2
I'd like to give some background to some question
I need to ask.
I've been using a high-pressure water/air water
misting system on a Peugeot DW10B engine for research on emission control in
diesel engines. Presently I'm using a Kärcher pressure washer pump, with an
external variable regulator for the water supply. I'm using a flow meter on the
injector inlet (for water) to control the amount of water injected in the
intake. Trouble is, I have to keep an eye on the flow meter reading while doing
the test, as a change in water injection rate changes the emissions
considerably. And I change the flow rate by hand by varying the water injection
Needing to develop a closed loop system, I'm
tempted by the Ulka pump, some reasons being:
1. It's cheaper
2. Less noise
3. Much lower power requirements
4. The Kärcher pumps 300+ kgs/Hr of water, I
recirculate it to prevent wastage, this heats up the water over a test period
causing further complications in repeatability.
5. Best of all, the Ulka seems much quieter than
6. I've killed off one Kärcher after a long test
period. It'll soon get really expensive as replacements will be needed.
I feel that it's better for the flow quantities
I'm looking at (In the region of 3 to 15 kgs/Hr at 6 Bar). I'd like to use the
pump in a closed loop setup coupled with the flow meter. To vary the flow rate
(piston stroke length and/or frequency?), I would imagine that a variation in
duty cycle or drive frequency would work.
Have you had any experience with this? Can I use a
type of AC signal conditioning to change the "duty cycle", so to speak? Or is it
best to use the piston/cylinder assembly and drive it using a new solenoid
winding at a lower voltage? That way I may be able to vary the drive
Any ideas would be greatly appreciated.
Thank you for a great magazine.
Samiur Rahman Shah
We trialled varying pump power and found that
any reduction in pump performance resulted in the nozzle just dribbling (rather
than atomising) as the pressure dropped away. We’d suggest the best approach
would be a methanol injector pulsed at high frequency and variable duty cycle,
used in conjunction with a pressure regulator on the Ulka pump. However, as
described in Part 2 of that series, this approach also has problems, especially
when flowing very small quantities of water. The simplest approach might be to
simply change nozzle size to vary the flow.
Water Injection Pump 3
Came across this: http://www.espressoworkshop.com/shop/shop133.html
Price is better than quoted in the article!
Well found! Footnote has been added to
Water Injection Pump 4
I have been reading with interest your stories on
the water injection system utilising an inverter and the ulka pump/spraying
systems UK nozzle. I have been working on a system almost identical for my
I too came to a similar conclusion with cooling
the pump, but developed a proportional controller utilising a PIC microprocessor
and a high-side driver for the ulka pump - as you are no doubt aware, the ulka
pump is a vibratory pump, which has a blocking diode so it is effectivly using
pulsed DC for the solenoid.
The flow rate and pressure of the pump may be
grossly controlled by reducing the pulse frequency (but not duration - a light
dimmer chops off either the leading or trailing edge of the pulse, so the piston
does not travel the full distance of the cylinder). This approach is taken in
several coffee machines, where the frequency is divided by a pair of 4017 decade
counters driving an SCR – this is the slow clunk, clunk when you are using the
steam function of most thermoblock coffee machines.
A similar approach may be used to control the
flow/pressure of the pump - by rectifying the output of the inverter (bridge
rectifier and a smallish cap removed from a computer power supply) and an IGBT
switched from the output of a PIC (which monitors the duty cycle of the
injectors, and compares this to an internal user programmed map).
The output of the pump may be increased by
increasing its frequency as well - these are specced for 60Hz as well, but may
be pushed higher if neccesary.
Another (far safer!) approach to this problem is
to get the pump in the 12V AC version - the thought of safely routing almost
340V DC (240 X 1.414 assuming a sinewave inverter) is just plain worrying!
Also - feel free to forward my email details to
last weeks response correspondent John Drewett ('Electric Bike') as I have a
large surplus of used but reasonable 7.2AH SLA batteries + heavy wires and
connectors + battery frames from a decomissioned 30KVA UPS that would be of use
to him - I can supply these gratis if he would like a few to construct his
electric bike - as he is located in Newcastle.
We have passed on your details to the bike
constructor. Re altering pump output: you have not mentioned the real problem -
what happens to the nozzle spray pattern when you drop pump pressure.
Water Injection 1
Just have a thought for the water injection
article. If you want water vapor, why not make a heat exchanger by wrapping
metal tubing around the exhaust? It will work like a coffee maker, but you will
have to trap and return liquid water. If you install it in the engine bay, you
can recover wasted energy and lower the temperature at the same time.
Because the change of state from water droplets
to water vapour, and the consequent uptake of heat, needs to occur in the intake
Water Injection 2
Re your Water Injection experiments. I did some
family reearch and found that a distant relative of mine was killed in 1944 when
the engine of his Messerchmitt Bf109G6 blew up shortly after take off. I
researched this aircraft, and found that they had an underbelly tank of 300
litres of 50% water/50% methanol injected into the engine. The idea was to
increase the boost, which took the engine from 1475HP to 1950HP. The cost was
enormous engine wear. I suspect a minor amount of water injection might be OK,
but a huge amount as the Luftwaffe was doing, was detrimental. Then again, if
you expect to get shot down in 20 hours, the engine only has to last 25.
Just like to pass on my compliments to your site,
I'm a bit of a newbie to it but I'm finding all your recent articles a pleasant
and insightful read. It's fast becoming one of my regularly checked sites!
I would like to put forward a suggestion about a
possible article and that is (a bit in the style of the recent 5 cent resistor
'mod') the throttle body coolant bypass modification. I have recently done it to
my car and I have noticed a change in how it drives, but what I would really
like to know is the technical side of what's going on!
We haven’t ever tried bypassing the throttle
body coolant supply but we assume it results in slightly cooler intake air
Sometimes you can say something and it causes a
trigger elsewhere. So thanks to the writer for "The electronic variable speed
controller ,,,,,,,, A better approach is to build a mechanical system that gives
the progression of trigger movement needed in the application."
Twenty minutes later I have a used a drill
controller (to drive transistors) as a core of a speed controller on my Dad's,
um, well, mobility scooter. The one he built himself. The one that uses two
starter motors and direct on/off drive. The one that goes about 40 miles an
Now thinking about using old drills as drive for
automatic door openers on my car,,,, Arrgggghhhh better still; drill motor and
perhaps two sets of reduction gears. A chuck. A length of threaded rod and a
bolt welded in the chassis, hey Presto! Built in electric jacks. Now how is that
for a theft deterrent??? (Or a simpler project is to electrify one of those
bloody awful scissor jacks,,)
In your recent article "crash boom bang" the first
line "every engine has them" made me want to cry. come on guys don't forget the
Measuring Performance and Fuel Economy
Some praise, a suggestion and a question. I can't
praise you enough for not only publishing relatively cheap methods for finding
more performance but also quantifying the gains - how often I've read in
magazines of "noticeably more grunt in lower revs" and longed for some figures
to verify such a judgement, I don't need to tell you.
What I'd like to read is a feature from you about
on-road-dynoing with a product like this: http://www.roadtune.co.uk/roaddyno.shtml
I've also read of a software that analyzes the
sound of a car and produces a dynosheet from this audio-data. Such a topic would
perfectly blend in with your other tech features, imho.
In the feature about modifying under-car airflow
said that quantifying the improvement "... is only applicable to cars with an
averaging fuel consumption readout" - I was wondering wether a precise speedo
and tacho won't allow similar conclusions? I guess fuel consumption algorithms
use the same data plus some constants. Less rpm for the same km/h = better
airflow? No need to answer directly, perhaps you can relate to that if you
revisit the article in the future or do a similar feature.
With regards to on-road dynos and the like, for
quantification of performance gains or losses, we don’t think a simple stopwatch
and the car’s speedo can be beaten for low cost and absolute on-road validity.
Fuel economy needs be measured by dividing distance travelled by fuel consumed;
it cannot be worked out by engine speed versus road speed (a relationship that
in the one gear, is constant in manual transmission cars and near-constant in
those with automatic transmissions).
Modification Direction 1
Re: Where to from here. I have a couple of points
to make about this overall well argued piece.
1. I wish a trailer could substitute for a ute. It
can if you are going from one spot in the suburbs or exurbs to another, but if
you are going to be dealing with angle parking, multi-level car parks or just
about any shopping centre that I have dealt with, then a trailer is just not
going to work. The result is that I rent a ute about once a month. Which ALMOST
works out money wise.
2. Current police attitude to wheel spin makes
traction control and/or 4wd even more of a performance advantage than the
practical results would suggest. Driving a RWD or (worse) FWD requires such a
significant margin of safety when it comes to the right foot that even a
"slower" 4wd is a much faster car if you are in a strictly policed area.
3. Modifying a hybrid may be fairly daunting for a
Prius, but surely the Insight is much more straightforward? Autospeed's own
articles on modification of the lean burn system suggest this.
4. Tangentially, could an aftermarket lean burn
system be possible? The aftermarket now has far more computing power than
manufacturers had in the mid 1980s.
5. I've seen the advantages of smaller (but higher
boost) turbos and higher profile tyres touched upon at some of the more
technical webforums, but Autospeed has yet to look at any of this.
As you can tell, this is the sort of article that
gets me thinking.
Modification Direction 2
Regarding your article 'Where to from here?' you
stated that you would be happy to see fuel prices around $3 to $4 per litre.
I think the federal and state governments would
dearly love this too!
correct me if i am wrong (i am bad at maths) but
at these fuel prices, wouldn't the taxes be in the order of $1.20 per litre?
Last year my wife and i visited her family in
Austria and Switzerland and i took notice how much it costs to get around. in
AUD terms it was freakishly expensive but was only marginally more in referance
to their cost of living. it must be a cultural thing but even when people have
nice cars, they still walked or trained to where they wanted to go.
i agree that personal use must be curbed, but
raising fuel prices will raise the cost of EVERYTHING that needs to be
transported. And Australia is more succeptable to this as your nearest foreign
country (aand trading partner) isn't just a 20 minute drive away.
Conductive Glass in Spark Plugs?
"The centre piece of conductive metal stops short
before it gets to the electrode, with the gap between it and the electrode
filled with conductive glass material."
This is the first time I've heard of "conductive
glass material." ...I use glass for an insulator in my Lyden jars. I'll be more
careful in the future. <grins>
The most recent edition of the Bosch Automotive
Handbook (6th edition – page 628) says the same thing: “... an electrically
conductive glass seal forms the connection between the centre electrode and