Direct Injection Engine

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Can you contact Hyundai US and get some engineering feedback on the test engine(s)? This one sounds like a leading design, with excellent performance and durability. As a prospective customer, it would be interesting to see if they would truly expend the energy to get you the answers.

Wonder how flat the torque and hp curves are?
 
Wow, built in USA to boot. I will seriously consider one of these when my Camry hits 250K/2015/Totaled by some idiot, whichever comes first.
wink.gif
 
There have been a few di problems. The biggest one is that fuel doesn't wash down the intakes any more. So there are some problems with build up from the pcv system. The second problem you hear about is fuel dilution problems. Though I think this is more of a di forced induction caused problem rather than di just alone.

As for mileage I think you will see most manufactures matching those number in a year or 2. GM's current Malibu doesn't have the di engine yet and rats at 33 for the highway. Assuming a 10% gain for there di engine and you end up at 36. In other words I am saying it is pretty much with the pack of the rest instead of really leading.
 
Originally Posted By: SrDriver
I am wondering what the problems direct injection can cause in the long term?


I haven't had any problems with my Turbo Direct Injection engine, and I can't think of any reasons why a gas engine would have problems with my diesel engine hasn't.
 
Originally Posted By: Tornado Red
Originally Posted By: SrDriver
I am wondering what the problems direct injection can cause in the long term?


I haven't had any problems with my Turbo Direct Injection engine, and I can't think of any reasons why a gas engine would have problems with my diesel engine hasn't.


its a basic difference in the engines. A diesel burns on the whole stroke down. In other words the injector keeps injecting fuel. The gas engine is a little different. It injects the fuel then lights it off with a spark plug. To my understanding this has a greater chance of fuel dilution.
 
Originally Posted By: wapacz
Originally Posted By: Tornado Red
I haven't had any problems with my Turbo Direct Injection engine, and I can't think of any reasons why a gas engine would have problems with my diesel engine hasn't.


its a basic difference in the engines. A diesel burns on the whole stroke down. In other words the injector keeps injecting fuel. The gas engine is a little different. It injects the fuel then lights it off with a spark plug. To my understanding this has a greater chance of fuel dilution.

That may or may not be true -- modern engines can have several injections and several spark ignitions per piston stroke. I would think they'd not want to waste any fuel by having uncombusted fuel washing down the cylinder walls.

Quote:
EGR is the problem with direct injection - petrol or diesel.Causes blocked intakes and inlet valves.

I don't see the connection. If EGRs are going to clog, they could do it in a non-DI engine. OTOH, EGR clogging is not so much a problem with low-sulfur fuel. Both diesel and gasoline are very clean these days.
 
Pretty much going off of what I have read in other places.

I think the basics of it is that a diesel waits to the top of the compression stroke. Then injects the fuel which auto ignites then keep injecting fuel till close to the end of the stroke. Where as in a car there is a period of time where the fuel is there and not burning. Some one had a really good write up on it and I wish I could find it again.


There are deposit problems but diesels see them also. Its a matter of fuel no longer washing over the valves. So build up can occur. But from I have read its the pcv system that causes it.
 
Originally Posted By: Tornado Red
I don't see the connection. If EGRs are going to clog, they could do it in a non-DI engine.


I work on Mitsubishi GDI engines,and common rail direct injection diesels - the amount of deposits has to be seen to be believed,in the GDI it almost blocks the intake ports.The deposits are after the EGR port,some is from the PCV,but the large amount of deposits are EGR.

We had a Nissan ZD30 apart last month,this is a direct injection,but not common rail diesel.It is 4 valve,with completely different ports and runners for each valve...one valve does clean air with PCV,the other is the EGR intake.Only the EGR ports and valves had heavy deposits,the other intake system had oily ports with no deposits.

In theory EGR may not cause problems,in practice it is a very big problem.
 
What kind of fuel are you running in these engines? Low-sulfur or ultra-low-sulfur diesel?

I don't see why whether the fuel and air are mixed in the cylinder head or in a pre-chamber should make any big difference.
 
We have low sulphur diesel,I'm not sure what's down to now,but I'm sure our fuels are of low standard,although we pay premium price.Have you seen what comes out of a diesel exhaust? Soot,which is carbon,mix with a bit of oil and send it down the intake and it'll make some sticky gunge.Mitsi recommend a 60,000km intake clean I think...so they know it's happening.We do it at 75,000km.Shannow has the low down on what Nissan are up to.Toyota keep it all under wraps,but we know there are problems.There wasn't much of an issue with the old indirect engines,although we disconnect the EGR soon as they give trouble.

With the GDI there is certainly a fuel issue,these engines are Japanese market only...at the end of their designated lifespan they end up down here.Injectors,plugs and coils....and blocked intakes are just everyday GDI troubles.
 
I've had a ZD30 for 82,000km, running on 50ppm max.

Pulled the EGR gasket from the EGR pipe to the intake, and it's around 40mm hole, that was 1/8 clogged with soot.

This area of the manifold has NO exposure to PCV fumes.
 
The one we pulled down was 1/4in thick at 160,000km....so twice as thick for double the kms.I won't tell you what we did to it,but it's gone to auction...never coming back here.
 
GDI = GASOLINE Direct Injection. Note the emphesis on the word "GASOLINE".

A Nissan ZD30 is not a GDI, it is a diesel.

You cannot compare deposit formation between a gasoline and a diesel engine. First, diesels use HUGE amounts of cooled EGR to control NOX, especially those not using an SCR system. We're talking like 25-35% EGR dilution of the intake charge at times, compared to 3-5% in a gasoline engine. As a matter of fact, most gasoline engine have eliminated the EGR valve as VVT allows for controlled reversion of the exhaust though adjustments in cam timing.

EGR contamination on a modern gasoline engine (direct injection included) is virtually non-existant, mainly because there is no EGR valve!

Now, there have been cases of deposit formation caused by the PCV system in some direct injection gasoline engines. This heavily affects VW in particular. However, there are plenty of other DI engines out there with no issues and more than a few simply believe VW just designed a poor crankcase ventilation system.
 
Makes me want to stay away from direct injection engines....although we may be screwed if this is what most or all manufactures will be going to.
 
Originally Posted By: ARB1977
Makes me want to stay away from direct injection engines....although we may be screwed if this is what most or all manufactures will be going to.


All new technologies have teething problems. DI's are fuel dilution, intake valve deposits from the PCV.In time they will be sorted out. Maybe reroute the PCV and create it's own special vacuum pump instead of using the intake.
 
Originally Posted By: ARB1977
Makes me want to stay away from direct injection engines....although we may be screwed if this is what most or all manufactures will be going to.


Really they are minor problem for what the tech brings to the field. GM has a 250 hp 3 liter engine with di. Before di they needed a 3.6 liter to get that amount. This allows them to put a smaller engine in the same car and get the same performance while at the same time getting better gas mileage. Due to the reduction in displacement and the higher efficiency that di affords.
 
I believe Toyota has already figured out how to make a DI engine without the typical deposit formation issues. I'm sure others will figure it out as well in not too long.
 
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