HDI

[205GRD]

I was just woundering what the difference was between the HDi and the older diesel made by pugeot and what the basic differences were.

[PowerLee]

Hi

Have a look at this link here for nearly all the HDI information you will ever need.

www.christiantena.pwp.blueyonder.co.uk/motor/peugeot/hdi/hdioperation/index.html

I do know the fuel pressure in the metal pipes under the bonnet can reach 19 & a half thousand PSI! So dont play about with it if you dont know what your doing!

Also you cant pressure wash or steam clean the engine, You will ruin the electronics.

If you unplug a HDI injector while its running the engine will suffer a hydraulic lock & punch the con rod thought the side of the block in under a second.

[504gld]

There are still in production around the world a few light diesel engines of the Peugeot family.

XD
XUD
TUD
DW (non turbo)
DW (HDI)

The XD series, was the first for Peugeot passenger cars, as a 1.9, getting bigger to 2.1 and then 2.3. When it was fitted to the 604 and a turbo added, became the first TD available in Europe.

XUD hit the UK market in the Talbot Horizon way back in 1982/3 as the 1905cc version (despite Horizons being built at Ryton, all Horizon diesels were built in France!). It was quickly followed by a 1769cc version of the Peugeot 205. Citroen BX pursued in 1984 using the 1905cc version at the same time Peugeot 305 MK2 switched to it from the old 1.5D (no longer made today). The rest of the models are basically history, all Peugeot/Citroens until 106/AX came along. They used a (then new), TUD engine of 1360cc, exactly the same CC as the petrol. This engine used a lot of common parts as the petrol making it easy to build and develope. It later grew to 1527cc.

The DW non turbo engine is a newer design, not so dis-similar to the XUD, but much more updated, I don't know a lot about it, except its normally 1.9 non turbo.

All of these engines are indirectly injected, and use mechanical driven fuel pumps. This means that fuel is pumped up from the tank, and distributed to each fuel injector one at a time. The injector sprays the fuel in to a small chamber within the cylinder head, where the "explosion" and burning of fuel starts to take place, before it spreads in the cylinders of the engine and does all the work. Indirectly injected engines were much more quieter but not as fuel efficent.

HDI works differently, fuel is drawn up from the tank by a pump. Each fuel injector is electronically controlled by the ECU (the brain!). Fuel is kept under very high presures all the time in a distribution rail which each injector in connected to. Unlike the other engine, fuel is not distributed to the injector, its there all the time. The injector allows the fuel to pass through it at the correct times. Think about a light switch, the electricity is there all the time, flicking the switch on and off, lights the bulb. The other main difference is this is a Directly Injected engine. The fuel injector sprays the fuel directly in to the cylinder, there is no smaller chamber like on XUD. Modern design and technology has minimised the extra noise this creates, and has raised fuel economy and power.

[205GRD]

thanks for that
I was just woundering how they worked after hearing various people raving about them after they had driven them, and woundered what the difference was to the XUD in my car