450 AD

Japan's First Diesel Engines for Motor Vehicle Applications

In 1931, in response to fuel supply shortages, Mitsubishi developed Japan's first diesel engine for motor vehicle application. Experiments were made with several different types of fuel, all of which presented drawbacks in either performance, ease-of-use or maintenance. After much trial and error, the 450AD direct injection diesel engine with a displacement of 7,000cc, 70ps/1800rpm was developed at the Tokyo Motor Vehicle Works. This diesel engine was first adopted in an armored type vehicle

In 1932, Mitsubishi engineers developed the 445AD engine for truck application, boasting a reduction in size while increasing the power output. With a displacement of 6,700cc and a maximum output of 70ps, the 650AD engine was introduced in 1934 for use in one of Japan's first diesel buses, the BD43. These engines were to help firmly establish Mitsubishi reputation for designing fuel efficient diesel engines.

In 1935, the 85ps, SHT6 pre-combustion type diesel engine was designed and developed in Kobe. The SHT6 engine proved to be highly reliable and in the following year was adopted in Japan's first domestically produced diesel bus, the BD46. Based on the SHT6 engine design, the Y6100 engine was developed in 1938. This 8-liter, pre-combustion chamber engine boasted a power output of 100ps and became the standard engine for diesel powered large-size buses in Japan.