History of Mitsubishi Diesel Engines
Mitsubishi was the first Japanese company to recognize the Heaven-made match of Japanese reliability and diesel efficiency. The company has been drawing on its origins as an aircraft manufacturer for nearly 60 years to produce a line of diesel engines that are renowned for their durability and fuel efficiency, if not for power and clean emissions. Those shortcomings have largely been addressed with the newest generation of Mitsubishi diesels.
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Basic Description
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All but the most recent of Mitsubishi's diesels are four-cylinder engines denoted by the letter D, as in 4DR and 4D5. All are under 3.5L in displacement, and produce less than 200 horsepower. Except for the newest 4N1, Mitsu's diesel engines were JDM (Japanese domestic market) and were never designed for exportation, although some made it to the U.S. anyway.
Engines
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The company's first diesel was the 4DR inline four-cylinder engine, available in both the 4DR5 and low-compression 4DR6 configurations and produced from 1953 to 1998 for Japanese market Jeeps and trucks. The 4DR's successor was the 4D5 family of diesels, derived from the "Astron" four-cylinder in 1986 and still in production today. The newest generation is the 4N1 "clean burn" family, which hit showrooms in February of 2009.
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Aspiration
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Prior to the proliferation of turbocharging in the 1980s, almost all diesel engines worldwide were naturally aspirated. The 4DR was no exception, as it ran turbo-less in both variations. Although decent by the standards of the time, the 4DR's 94-100 horsepower rating seems less than impressive today. The 2.3L Astron 4D5 was introduced in 1980, received an increase in displacement to 2.5L and came in several configurations with power ratings that varied from 95hp (non-turbo 2.3L) to 178hp for the newest turbo-intercooled 4D5s. The 4M4 engine came along in 1996 with a variable-geometry turbo, and succeeded but did not replace the 4D5.
Models
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The 4DR engines were used in Mitsubishi's line of Jeep off-road vehicles, which were built under license from Willys, AMC and then Chrysler. The Astron diesel replaced the 4DR engine in all of Mitsubishi's light trucks, was the first diesel ever installed in a Japanese passenger car (Colt and Galant) and is still in service today as a low-end engine option. The 4M4 was first introduced in Mitsubishi's line of Pajero/Shogun/Montero SUVs, and currently sees service in the Pajero, Triton and Strada. All of Mitsubishi's diesel engines are currently being phased out for replacement with the cleaner-burning 4N1 engine.
Emissions
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Mitsubishi's engines have grown progressively cleaner over the years. The 4DR was not subject to emissions testing for most of its lifetime, and is not known for its eco-friendliness. As it was derived from Mitsu's advanced 4G family, the 4D5's emissions are significantly better than most other diesels of the day, and continue to exceed federal emissions standards. Along with an emissions-oriented computer tune, the 4N1 uses a Diesel Oxidation Catalyst (DOC), NOx Trap Catalyst (NTC) and Diesel Particulate filter, which make any vehicle so equipped on the verge of being an ultra-low emissions vehicle.
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References
Resources
- Photo Credit old jeep on a hill image by Roman Barelko from Fotolia.com
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Comments
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The 4dr5s emmissions are significantly better than most other diesels of the day and continue to exceed federal emissions standards.
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gaz 69 engine 4DR5
