Sulu

In theory, compression-ignition diesel engines are simple and should be reliable, but in continued efforts to make them cleaner, new technology is being added that adds to complexity and may reduce reliability. There is the very-high pressure fuel delivery (high pressure common rail fuel injection). There is diesel particulate filter (DPF). There is selective catalytic reduction (SCR) with diesel exhaust fluid (DEF / AdBlue).

mmarshall

Are you old enough to remember the GM 5.7L (350 c.i.) diesel V8 of the early 1980s....the one that was converted from the gas-powered 5.7L? There was an unreliable POS if ever there was one.....the object, I might add, of a class-action lawsuit. In fact, back then, from what I can remember, the only decently reliable automotive diesels in the American market were from Mercedes and Peugeot....and the Peugeot diesel cars, though reliable in the engine department, had a lot of other problems typical of French products.

Technology or not, I think you and I can both agree that most of today's automotive diesels are a lot more reliable than back then.

Sulu

I don't think we will see any Toyota diesel vehicles here in Canada and the USA any time soon. I can understand why.

• It costs money to certify a new model for sale here. The costs are likely (much) higher because of our unique safety and emissions regulations; if the USA and Europe could come to an agreement on harmonizing safety (lights, bumper strength, etc.) and emissions regulations (USA has much more stringent emissions regulations than Europe, especially for diesel vehicles), it would be easier -- and therefore cheaper -- to certify a new vehicle for sale here.
• It costs money to import, sell and service a new model.

Because of these costs, any manufacturer will be expecting a certain critical volume of demand before it decides to bring in a new model. Toyota is not known to be a big risk taker; if it does not believe that there will be demand for a model, it will not import and sell it. We all remember why the Celica and Supra were discontinued last decade: too little demand.

If you want a Toyota diesel truck, the best you could hope for would be a North American-produced truck, like the Tacoma or the Tundra. It would be cheaper to certify a domestically-produced diesel truck for sale than an imported model. This is what Nissan is doing -- offering a diesel on a North American-produced pickup truck. But Nissan is offering a third-party (not produced by Nissan) engine, which is something that Toyota is very unlikely to do. Toyota prefers its own engines and transmissions in its vehicles (which would likely make a Toyota diesel-powered Tundra more expensive than the Nissan truck). Nissan needs to offer a diesel, in an effort to compete with Toyota for the #4 spot in full-size pickup truck sales. Will Toyota offer a diesel in the next-generation Tundra? I do not know. If Toyota needs a diesel Tundra to be competitive (and sell enough models to justify the costs of production), a diesel Tundra may be offered.

Toyota does not seem to really care for diesels; it does not offer a wide range of diesel engines. The new GD family of 4-cylinder diesel engines, offered in the Hilux pickup truck, is available with DEF/AdBlue aftertreatment, so theoretically could be made compliant with American emissions standards but I don't have the impression that Toyota wants or needs to sell a wide range of diesel vehicles. It has decided to invest in hybrid-electric vehicle and hydrogen fuel cell electric vehicle technology rather than diesel. It likely sees a greater demand in the future for electric vehicle technology rather than diesel engines in its light-duty vehicles.

mmarshall

If you are referring to the Cummins diesel offered in the Titan XD, that's probably not a bad decision on Nissan's part. By truck standards, Cummins makes a pretty good diesel.....Dodge Rams, of course, also use them. Of course, demand for the Titan has always been low, whether gas or diesel

Toys4RJill

I think the next gen Tundra will absolutely have a diesel engine. I doubt it will be built in house.

Och

iTrader: (3)

No, just no. This couldn't be further from the truth. Maybe engine blocks and rotating assemblies are made with more precision and are more durable, but the old mechanical fuel pumps were a million times more reliable than modern fragile high pressure assemblies, and there was no EGR system that causes intake manifold, port and valves to clog up with carbon and gunk within 20k miles (reducing power and efficiency), there was no costly SCR system or costly multiple catalytic converters. Not to mention that these old diesels could run on pretty much anything - diesel, crude oil, motor oil, use cooking oil, etc.

mmarshall

What you are refering to, though, is durability, more than reliability. The two sometimes go hand in hand....sometimes not. The famous Chrysler 3.7L slant six, for example, was arguably one of the most durable engines of all time, but, with Chrysler's notably poor electronics in that era, not necessarily the most reliable.


Even some modern diesels can run on home-made fuels or cooking oil (providing, of course, there isn't any sulfur in it). Unfortunately, many jurisdictions don't allow that, because of the state and local taxes imposed on diesel-fuel (money always talks LOL). To use home-made fuels, in the eyes of the state, is like moonshine that is done for tax-evasion....some car-owners have actually been prosecuted for it.

Och

iTrader: (3)

A modern diesel will barely last 100k without needing constant expensive maintenance and repairs, while old diesels rack up 300-500k, and they are simple and inexpensive when it comes to repair. But to be fair, the same is true for modern turbo charged direct injected petrol engines.

They can run on cooking oil, but not for long - just a little bit of contamination will destroy these high pressure injectors and a little bit of water will cause catastrophic failure. Traditional diesels can run pretty reliable on cooking oil thats been put through a paper/cloth filter, provided that it's not too cold out where its starts to jelly.

SW17LS

I'd like to see the factual data you use to back up the statement "a modern diesel (or turbocharged gas engine) will barely last 100k without needing constant and expensive repairs". Bold statement, and I'm willing to bet money you have nothing to back that up but your own assumptions.

SW17LS

Because I've driven and ridden in several modern diesel passenger cars, I have a nose, and can smell. I don't smell any smell.

"Because you said so?" LOL, what a ridiculous question. Who says they smell? Because YOU said so? You must have a much more acute sense of smell than me

mmarshall

Two reasons (among many) WHY modern diesels don't stink as much, of course, are the introduction of the low-sulfur diesel-fuel (think back to your high-school chemistry-labs......sulfur compounds are notorious for their odors) and the injection of the urea-solutions, which help the catalytic converters burn up the soot (solid particulates). Older diesel engines usually did not use carburetors, but, even so, the air/fuel mixtures today are far more precisely regulated by today's diesel-injection systems than those of the past.

Och

iTrader: (3)

Mike, first of all there is no such thing as a diesel carburetor, diesel engines do not even have throttle plates to restrict air flow. Air to fuel ratio does not matter in a diesel engine, so in modern diesels they make the air/fuel mixture as lean as possible at all times with the turbos forcing as much air as possible. The leaner the mixture, the cleaner the fuel burns with less smoke. This is why you see some German diesels with three turbos creating very high pressure.

And then of course you have modern diesels with SCR systems, and those completely break down the byproducts of burning diesel fuel. For instance my MB Sprinter produces absolutely no smoke or diesel smell. However there is pretty noticeable ammonia-like exhaust odor.

Och

iTrader: (3)

I absolutely stand by what I said, and there is plenty of evidence. I'm not going to waste my time breaking it down if you're only looking to argue, but if you're interested I'll be more than happy to explain this.

SW17LS

I'm not looking to argue, I just know that you don't have any evidence to back that statement up.

mmarshall

Correct. I wasn't disagreeing with you. That's why I said most older diesels didn't have carbs (It's possible some did on rare occasions, but I don't remember any).

I'm not trying to deliberately argue, but I can't totally agree with that. The air/fuel mixture, even in a diesel, does matter to some extent. A diesel engine works by ultra-high compression ratios of (roughly) 20:1, as opposed to those of a typical gas engine about half of that, at 10:1. In general, the heat of that high compression fires off the air-fuel mixture, rather than an electrically-generated spark. The air-fuel mixture has to be tuned and regulated for the exact characteristics of the heat and compression each engine will generate, or else it could fire off or ping/detonate too early, causing possible internal engine damage, or too late, wasting power and adding to emissions.

One reason, BTW, why so much pressure is needed on injection, because the high compression creates so much back-pressure. It's like a tug-of-war....and the high-pressure injection system has to win if the engine is going to run at all.