Kubota Engines & Indirect Injection

Muhammad · May 2, 2000

I was just browsing the features of the new models recently listed on Kubota.com, and something caught my eye.

On all compact and utility tractors up to the M9000, the engine details are listed as indirect injected. (M110 and up are direct injection, BX-series engines did not mention direct or indirect)

Now while it isn't much of a topic these days, I remember years ago the long battles I was part of over the direct vs indirect issue... the end result usually wound up being that direct injection was better for a number of reasons. (Some even brought up the different injection methods when comparing a big-3 manufacturer’s tractor to a ‘China-made’ tractor, saying that the rougher running, less efficient indirect injection is just a sign of a lower-quality tractor.

So since Kubota had been known, by me anyway, for the direct injection engines, seeing the new models all being indirect shocked me a little bit. So, I went and got some older sales guides I have from earlier model year Kubota tractors (pre-90's), and found the engines to be listed, and features as, direct injection. Kubota even listed all the benefits of the direct injection engine over the indirect, along the lines of...

+ Direct injection converts fuel energy into more power.
+ More efficent combustion.
+ Better fuel economy.
+ Heat efficency is increased.
+ 'Dramatically' improved oil usage.
+ Lower exhaust emissions.

I thought maybe the website had some incorrect data, but I checked my most recent published information only to find no mention of direct injection in the current models. But my last hope alive, since they didn’t mention the engines being indirectly injected.

Thoughts/comments?

<font color=blue>>></font color=blue>Muhammad
<font color=blue>Forum Master</font color=blue>

Anonymous Poster · May 2, 2000

All the Kubota engines that have the E-TVCS (three vortex combustion system) are indirect injection. This goes back at least to the start of the B1700-B2400. I am not sure about before that(B1550-B2150). I always assumed they were indirect injection like the later models, but maybe I was wrong.

Direct or indirect has nothing to do with the quality of an engine, it is just a different way of supplying the fuel.

The Kubota indirect injection engines were the first small diesel engines to meet the CARB ULGE emmision regulations. Maybe this is why the B1700-B2400 show less visible smoke than the previous series. Kubota also claims the E-TVCS (indirect injection) makes for easier starting and less noise.

In theory the direct injection should have some advantages like those you listed. In practice it seems it may be more difficult to consistantly get those advantages. What kind of injection system did those smoking Boomers have?

Andy

MChalkley · May 3, 2000

Everybody who makes diesel engines has talked about the advantages of direct injection vs. indirect injection for as long as I've been following the literature. The touted advantages appear to be identical, with indirect injection being much better in every way when the manufacturer in question uses it, and direct injection better in every way when the manufacturer chooses that approach. I noticed a couple years ago that Kubota is one of the few to have committed the gaff of switching approaches and continuing to explain that whichever one they're currently using is the best. I'll have to dig up some of my older brochures for the exact wording, but I remember noticing it when I was looking at the L4310.

The only advantage that I've ever seen mentioned by independent sources is that engines with glow plugs can be started in colder temps easier when they're indirectly injected. But direct injection engines have ways around that, too, as with Cummins' intake heater grid. Just don't ever shoot ether into an engine with one - the results can be spectacularly unpleasant!

Indirect injection engines also tend to be a little quieter. But both camps have claimed efficiency advantages, so I don't know whether either has any real advantage there. I do know that the new VW engine is direct injected and they made a big deal out of the efficiency gains of that approach when they introduced the TDI (which stands for Turbo Direct Injection) engine. I do know that it is a tremendously more efficient engine than the older ones, but computer control may be more of a factor than direct injection - I don't know.

Mark

PaulB · May 3, 2000

Having recently completed my phD (phony Degree) in diesel mechanics, please allow me to clear up this issue. I know the engine (or is that motor) on my beloved B1700 has DIRECT fuel injection because I always pour the diesel DIRECTLY from the can into the fuel tank. On the other hand, it may have INDIRECT injection, because if I do spill some fuel onto the hood it them drips all over and takes an INDIRECT path to the garage floor. That being said, my monthly ppayments come DIRECTLY out of my pay check, but it took considerable slight of hand and INDIRECT reasoning to convince my wife to let me buy it in the first place. ...I sit DIRECTLY on the seat to drive it, but I have to take an INDIRECT path out to the barn or I will run into the house...first thing in the morning I usually come DIRECTLY to the computer to go to tractorbynet, but sometimes I stop in the bathroom first, so that would be INDIRECT... I am so confused. What I do know is that I get 10 hours of use out of 5 gallons of diesel, it doesn't smoke at all, has hardly any smell, starts at 5 below zero, etc, etc, so in the end I don't think the concern of direct vs indirect is nearly as important as the quality of engineering and manufacture that goes into the motor.

Bird · May 3, 2000

I couldn't have said it better myself, PaulB (or even half as well)./w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif

Bird

MChalkley · May 3, 2000

PaulB, I don't have the benefit of your education, and clearly your exhaustive research in the field (sorry) of manure spreaders has considerable bearing on your eloquent dissertation on indirect vs. direct injection. However, unless I'm very much mistaken (and I may well be) you're confused on the meaning of the terms. Direct injection does refer to pouring fuel directly from the can into the tank, but indirect injection is not the spillage running onto the floor, but measures taken to prevent this spillage - i.e. use of a funnel or pump device with a hose, thus the term 'indirect' (via the funnel or hose) injection.

I hope I may have cleared any small confusion that you may have had. If you have any further questions, perhaps you should consult some more knowledgeable than yourself in the area of manure spreaders - assuming such individuals exist, I'm sure they could be of considerable assistance.

Mark

W5FL · May 3, 2000

The best injection method seems to be in the eyes of the beholder!

Sorry, but can't tell much difference. The late model Kubota engines seem to run smoke free. When I lived in California, they sent a little guy to all construction sites and wrote expensive tickets if you did not have spark arrestors, approved emission controls, oil leaks, etc. Now the same laws are applicable to all states and nearly all new engines run very clean, but the approach seems to vary from manufacturer to manufacturer.

Kubota starts and runs smoke free and runs well. When I test drove a John Deer 5310, the dealer kept telling me that they used to run fine before all the emission controls and it will run ok once it warms up. It did.

I bought a Kubota. /w3tcompact/icons/smile.gif /w3tcompact/icons/smile.gif

PaulB · May 4, 2000

Mark - I do believe that you are in fact an individual more adept at the spreading of "manure" even than I, so I will accept your modification of my use of the terms direct vs. indirect. thank you for your valued input. /w3tcompact/icons/smile.gif

Billc · May 4, 2000

Paul, your "direct vs indirect" post was a work of art!

MChalkley · May 5, 2000

I humbly accept your assessment of my abilities, knowing as I do from experience that you are truly gifted in this area. There is no greater honor than recognition from a true expert. /w3tcompact/icons/wink.gif (This, by the way, is an example of indirect recognition. Not to be confused with direct indigestion, a direct by-product.)

Mark

rocknrod · Oct 29, 2010

Re: Kubota Engines & Indirect Injection

Well this answers allot of my questions on indirect injection. As well as giving a laugh in the morning.

art · Oct 29, 2010

Re: Kubota Engines & Indirect Injection

Just can't seem to find anything better then a little chit chat at Tractorbynet!!

zoltanthegypsy · Oct 29, 2010