Mitsubishi 6D22T Specifications
| Engine Model: Mitsubishi 6D22T |
| Engine Type: 4-cycle inline 6-cylinder turbocharged liquid-cooled diesel |
| Total Displacement: 680.5 cu.in (11.2 L) |
| Rated Engine Power: 240-270 Hp (178-200 kW) at 2200 rpm |
| Fuel System Type: Direct fuel injection |
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The Mitsubishi 6D22T is a turbocharged, inline
six-cylinder diesel engine developed for heavy-duty trucks, buses,
construction machinery, and industrial power units. It belongs to the
larger-displacement segment of the Mitsubishi 6D-series and was
engineered to deliver high torque output, long service life, and
dependable operation in demanding commercial environments.
The 6D22T is built with robust materials, a large-capacity cooling
system, and a mechanically governed turbocharged induction system that
enhances pulling power while maintaining reliability. Throughout its
production lifetime, the engine earned a reputation for stable
performance under sustained heavy loads, straightforward maintenance
procedures, and strong resistance to thermal stress.
The Mitsubishi 6D22T engine has a displacement of 11,149 cc, or 11.15
liters (680.5 cubic inches). This large displacement is achieved by a
bore of 130 mm (5.12 inches) and a stroke of 140 mm (5.51 inches).
The compression ratio is 16.5:1. The engine follows the four-stroke
diesel cycle and employs direct injection. The firing order is
1-5-3-6-2-4. Engine power varies depending on market tuning, typically
between 240 and 270 hp at approximately 2,200 rpm, with torque in the
range of 950 to 1,200 Nm (700 to 885 lb-ft) around 1,400 rpm.
The engine block is cast iron with heavy ribbing for rigidity. The
crankshaft is forged steel, supported by seven main bearings for smooth
rotation and minimal vibration. Pistons are made of aluminum alloy with
reinforced ring lands to withstand turbocharged cylinder pressures. The
pistons use three-ring configurations with two compression rings and one
oil control ring. The connecting rods are forged steel with robust
big-end bearings to handle high load stresses.
Cylinder heads are cast iron with individual intake and exhaust ports
for each cylinder. The valvetrain uses overhead valves actuated by
pushrods and rocker arms, driven by a gear-type camshaft system. The
system is fully mechanical, designed for reliability and ease of service
in remote environments. The intake valves are large to accommodate high
air volume required by turbocharging, while exhaust valves are built
with heat-resistant alloys.
The 6D22T uses a fixed-geometry turbocharger to increase air density
entering the combustion chamber. Boost pressure typically ranges from 80
to 120 kPa above atmospheric pressure (12-17 psi).
The turbocharger is lubricated by the engine’s pressurized oil system
and cooled by both oil and radiant heat dissipation. The turbine housing
is cast steel and built to endure high exhaust temperatures. Turbo lag
is moderate but acceptable for heavy-duty applications.
The fuel system is mechanical and uses an in-line injection pump. Fuel
injection pressure typically ranges from 21 to 26 Mpa (3,000 to 3,800
psi). Injectors are mechanical multi-hole nozzles with high atomization
capability.
Fuel delivery is controlled by a mechanical governor that regulates
engine speed under varying loads. The fuel filter system uses a primary
sediment filter and a secondary fine filter, ensuring clean fuel supply.
Fuel lift pumps are mechanical diaphragm types or plunger-assisted,
depending on model year.
The lubrication system is a full-pressure type with a high-capacity
gear-driven oil pump. Oil is routed through a full-flow filter and an
optional bypass filter for extended oil life. Total oil capacity is 24
liters (25.4 US quarts).
Standard oil pressure ranges from 300 to 500 kPa (44 to 73 psi) at
operating speed. Recommended oil grades include SAE 15W-40 or 20W-50
meeting API CF, CG-4, or higher specifications. Piston cooling jets
spray oil on piston undersides to maintain thermal balance during
heavy-duty operation.
The cooling system is water-cooled with a belt-driven centrifugal water
pump. Coolant volume is 38 liters (10 gallons). The thermostat opens at
82°C (180°F) and is fully open by 95°C (203°F). A large-capacity
radiator is required due to the engine’s high thermal load. Many
installations use multi-core copper-brass radiators. Some industrial
versions include an oil cooler integrated into the water jacket system.
| Intake and Exhaust Systems |
Air induction uses a heavy-duty air filter, often dual-stage for dusty
environments. The intake manifold is cast aluminum or steel. The exhaust
manifold is high-temperature cast iron and channels exhaust gases into
the turbocharger.
Exhaust temperatures may exceed 700°C (1290°F) under full load. The
engine is designed to maintain strong exhaust pulse energy to
effectively drive the turbocharger turbine.
Most 6D22T engines use a 24-volt electrical system. Alternators range
from 35 to 60 amperes depending on application. The starter motor is a
high-torque 24-volt unit suitable for cranking large-displacement diesel
engines. Glow plugs or intake heaters assist with cold starting. Some
versions rely on ether-start systems in extremely cold climates.
Engine length is approximately 1,450 mm (57.1 inches), width 850 mm
(33.5 inches), and height 1,250 mm (49.2 inches). Dry weight is between
980 and 1,050 kg (2,160 to 2,315 lbs), depending on accessories,
turbocharger configuration, and cooling system components. These large
dimensions make the engine suitable mainly for heavy-duty truck and
machinery frames.
Engine oil should be replaced every 250 hours or 10,000 km (6,200 miles)
under normal service. Valve lash should be adjusted every 20,000 to
30,000 km (12,000 to 18,000 miles). Fuel filters require replacement at
similar intervals. Air filters must be serviced regularly in dusty
environments.
Coolant should be replaced every two years or 40,000 km (25,000 miles).
Cylinder compression pressures are 2,800 to 3,400 kPa (406 to 494 psi).
Minimum acceptable pressure is 2,300 kPa (334 psi). Idle speed is
approximately 600 rpm.
Cylinder head bolts: 210 Nm (155 lb-ft).
Main bearing bolts: 260 Nm (192 lb-ft).
Connecting rod bolts: 120 Nm (89 lb-ft).
Flywheel bolts: 320 Nm (236 lb-ft).
Injector hold-down bolts: 28 Nm (21 lb-ft).
Valve cover bolts: 12 Nm (9 lb-ft).
Oil drain plug: 70 Nm (52 lb-ft).
Exhaust manifold nuts: 40 Nm (30 lb-ft).
The Mitsubishi 6D22T was widely used in heavy-duty Mitsubishi Fuso
trucks including FP, FV, and FM-series models. It also powered buses,
construction machinery, generators, marine propulsion units, and
industrial equipment. Its durability and simplicity made it popular in
export markets and developing regions.
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