I've just been reading about two-stroke diesel engines.  How come there aren't any cars or road vehicles with this type of engine?
Also, there are plenty of cars with turbo-diesel engines.  Why aren't there any cars with supercharged diesels?

Two stroke diesels generally do not meet emissions standards which is why they're being phased out in favor of four strokes.

Turbocharging is supercharging.  So is closing the exhaust prior to the intake on a two stroke diesel with a pressurized air box.

Blacksmith:  So Two-strokes are being phased out on ships, etc?  What makes the them have poor emmissions?

"Turbocharging is supercharging.  So is closing the exhaust prior to the intake on a two stroke diesel with a pressurized air box."

Sorry, I didn't quite understand your reply there.  I know turbocharging is a type of supercharging, but I meant why don't diesel passenger cars use crank driven Roots or Whipple (screw) type blowers?  Surely their ability to provide boost at low rpm would make them perfect for low revving diesel?

Swall: What were the "Detroit diesels" used for?

Beg to differ, ships do have emissions standards, International Maritime Organization has imposed standards, and while currently not as strict as other markets, are having an impact.  Also local air districts in many countries are imposing regulations that restrict using heavy fuel (HFO) on the mains within so many miles of port and for the ships service generators.  Emissions regulations are impacting all internal combustions engines, every year more applications and smaller and larger size engines are being affected.

Detroit Diesel was a brand that evolved from General Motors and Gray Marine.  The 71 series two stroke engine was developed in the 30's but didn't see much use until WWII.  Main use was engines for small marine craft, such as landing craft, tenders, harbor work boats, etc.  Towards end of war also saw use as generators and pumps.  It was a very durable and reliable engine for it's power density in it's day.  It was used in marine, power generation, on hiway and off hiway applications.  The original versions were the 6 and 4 cylinder 71 series, 71 cu/in per cylinder displacement.  The 53 series came out in the late 50's, and was in service until the 80's in lots of applications.  The product line evolved into two larger families, the 92 series, primarily used in on-hiway trucking but saw use in marine and power applications and the 149 series.  The 149 series was originally targeted for the oil and gas industries, mainly well servicing, but had a fairly good run for a short time in the standby power market.

As power density, fuel consumption and emissions improved on the four stroke engines, the two stroke just couldn't keep up in most applications.  High pressure direct injection fuel systems and better turbocharging proably the best mechanical contributors.

I thought there were some European light duty vehicles with a combination of small supercharger and small turbo, maybe someone here in the forum has more info.  I rented a Jeep Liberty in Denmark about 4 years ago with a small diesel power plant.  If I could have bought one in the US when I got back I would have.  I only glanced under the hood, but it was a nice package and it looked like it had a belt driven supercharger, maybe not.  But it ran great, used little fuel and was responsive.  I've heard Audi, Saab, Mercedes and Volvo have made great improvements in automotive diesels, too bad we don't get to see them here in the USA.

The 6-71 was commonly used as an over the road truck engine in the early to mid '70's in the USA.  It was referred to as the 235 (based on HP rating).  The 8V-71 was very commonly found both in trucks and buses until the 8V-92 came out and then no one wanted a 71.  In trucks that was before advent the days of the big bore high HP diesels.  For buses, they continued to be the engine of choice right up to the end of the last century.

Lots of 4-53's were retrofitted into pick up trucks by hobbyists, but it wasn't really widespread.  It made a nice PU truck engine.  If you had one, you could command a good price for it.  They would snap them up.  They were a popular replacement a lot of the early 5.7 and 6.2 GM and Ford 6.9 DI diesels.

Speaking of Detroit's, they blubbered oil terribly and they burned oil voraciously.  An early '90's vintage 8V-92 O&M manual I have states that the rated oil consumption for a 10 hour operating period (about 500 miles travel in an automotive version) is 1 gallon.  I think that was what it burnt, and didn't count what it leaked.  And, believe you me, it was right.  A tank of fuel was a guaranteed gallon of oil added.

Once I heard a trucker in the late '70's say to his buddy on the CB radio "you know, this truck of mine was prophesied about in the Bible."  His buddy - "what do you mean by that?" Reply, "Well, the Bible says that in the latter days there would be crawling and screaming creatures upon the face of the Earth, and it had to be referring to this Jimmy Diesel of mine."  

When Detroit Diesel determined to come out with a new engine in the mid to late '80's, they started with a clean sheet of paper and designed up a 4 stroke, and a good one at that as history tells us.

Based on the above, you probably couldn't give away a 2-stroke diesel to anyone in the heavy duty transportation industry in the USA, either based on their operating record or the current emissions regulations.

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