diesel sources

[ciaplayer83]

Hi, I have a Dodge Ram 2500 and love diesel engines. I chose to use diesel engines in passenger cars as a topic for an english paper. I was wondering if anybody had any ideas for quality sources for info and references.

[pgarner]

hey and welcome,

god another one for Hdi-fun.
what sort of info are you after ?

[ciaplayer83]

quality references explaining the properties and advancements made in diesel technology. I also wanted to include the concept of building power in a diesel allows for better gas mileage as opposed to the drop seen in petrol engines.

[pgarner]

building power in a diesel uses more fuel same as in a petrol. the big difference in the torque this means you dont have to put the foot down as heavily. if you were to keep the foot planted all the time youd us more diesel. the other advantage that gives diesel more milage is the fact that diesel engines dont use much fuel when cruising, alot of the time theyre just running on air, think the higher compressions allow this to happen.

of course the biggest development in diesel is the use of the common rail technology. this is where 1 fuel pump delivers it to the fuel rail where a second one increases the pressure to around 1200 bar (17640 psi) before being directly injected into the cumbustion chamber.
Another, no outdated, development was volkswagons PD system. these engines had a mini high pressure pump on each injector rather than the 1 supplying the whole rail. this gave much better power and economy over the common rail diesgns of the time. think a 1.9 with 150bhp but still easily capable of 60mpg on the motorway

Hopefully Hdi will be along shortly to give you more indepth reading.

Are you from the US, gas milage and the ram, didnt think proper diesels had caught on over there?

hopefully Hdi will be along

[pgarner]

should also have said most manufactures are now using common rail version 3
these allow silly pressure have heard of 1600 bar (23500 psi)

[pgarner]

Version 4 of CR is currently under development with rail pressure of 2000 bar ( close to 30000 psi)
http://www.swedespeed.com/news/publi...inter_272.html


take it youve checked out the common places

wikipedia unit injectors such as the PD system

Common Rail

[ciaplayer83]

Thanks, this should help. I am from the US, and no diesels have not caught on here, sad to say, but true. That is why I am writing on this topic, hopefully I can spread some light on the economical efficiency of diesel engines. So, I am understanding that I should use the huge torque in mid range rpms to explain the lower levels of fuel needed to maintain the current speed?

[pgarner]

yeah i think its the amount of torque that can be released from such a small amount of diesel that gives it the economy, like i say Hdi will be able to give you more indepth knowlage

[ciaplayer83]

Either way, thanks for the response and the input, every little bit helps. Thanks again.

[HDi fun]

Hello and welcome to Sillyland!

The reasons for the massive torque are thus:

1. The cylinder BMEPs (brake mean effective pressures) are very high;

2. There is no throttle as such;

3. Diesel fuel has a higher calorific value than gasoline litre for litre. (or liter even)

Where I think things might even out is if we compared identical MASSES of diesel and gas. Diesel is considerably denser than gas so we'd have less volume to burn. What I don't want to happen, therefore, is for the oil companies to start selling road fuel by the kilogram!!

In the UK we are now penalised to the tune of about 8p/litre for running diesel cars. So some of the economic advantages have been wiped out.

What a lot of people don't realise (or perhaps, don't WANT to realise) is that modern road car diesels really have progressed enormously.

It is, as PG says, in the fuel management department where this progress has been achieved. Direct injection into the combustion chamber is also helpful with fuel economy. Fuel pressures are insane, as PG has also pointed out. And the fuel delivery is timed very accurately. 3G common rail system can manage up to 4 injection phases per cycle.

Mine, which is quite early, and runs at a 'mere' 1300bar still achieves three phases per cycle. From what I understand the fuel management system delivers an initial dose of fuel to get thing started and then the main injection delivery takes place microseconds afterwards. This keeps combustion noise down to acceptable levels. The third phase is to do with soot filter regeneration, which I'm not going to cover here since it's a topic worthy of its own space.

[ciaplayer83]

Thanks a lot HDifun, I am trying to advocate those advance here in America. Its kind of funny to me that the only cars available in the US are European car manufacturers. Of course we have our diesel trucks but passenger cars just wont evolve here. I appreciate the info and I'm sure I will convince at least a few people of the power of torque. Thanks again.

[Chris Green]

Originally Posted by ciaplayer83

Thanks a lot HDifun, I am trying to advocate those advance here in America. Its kind of funny to me that the only cars available in the US are European car manufacturers. Of course we have our diesel trucks but passenger cars just wont evolve here. I appreciate the info and I'm sure I will convince at least a few people of the power of torque. Thanks again.

When you say there are no US diesel cars, do you have the diesel version of your Chyrsler 300? It's got a Mercedes-sourced in-line 6 diesel and sounds quite sweet from the outside.

[fwh]

Yeah I love diesels also. But what annoyes me is how the greenies have forced diesel particulate filters upon us. I have a 2007 diesel turbo sportage with a 'DPF' If you google 'DPF' you'll quickly see how many problems DPF's cause.

One it requires the vehicle to run hotter exhaust gasses and two burn more fuel with less power to accomodate and clean the DPF. The ECU's are tuned to protect the DPF so many people are having issues with their vehicles such as engine check lights and limp home modes setting in.

Later model diesels have common rail injection systems that run at very high pressure giving good atomisation of the fuel and resultant less soot and emissions, but still forced Diesel Partilcuate Filters upon us. I can see why US companies are reluctant to import diesel vehicles.

My own experience is that my DPF for some reason is faulty and continually have engine check lights and low power and poor fuel economy. Kia in Australia want to charge me $4,200.00 AUS for a new DPF filiter. I'm now forced to look at a ECU remap or completely new after market remapped ECU so as to ignore the DPF temp and pressure sensors.

As much as I love diesels if I had my way over again I would have bought a petrol version of the sportage. It is well recognised that for any given power output diesel vehicles are more efficient than petrol.

One must also consider that for every given barrel of crude most of it after production is diesel (light oil) and the least of it is petrol or gas. Thanks for reading. Regards. Fred.H