Mitsubishi S3E2 Specifications
| Engine Model: Mitsubishi S3E2 |
| Engine Type: 4-cycle inline 3-cylinder naturally aspirated liquid-cooled diesel |
| Total Displacement: 135.3 cu.in (2.22 L) |
| Rated Engine Power: 42 Hp (31.3 kW) at 2400 rpm |
| Fuel System Type: Indirect fuel injection |
____________________________________________________________________________________
The Mitsubishi S3E2 is a three-cylinder diesel
engine representing a displacement-increased evolution within the S3E
series, engineered to deliver greater power and torque while upholding
the established design principles of reliability and smooth operation.
This 2.2-liter, naturally aspirated power plant continues the use of an
indirect injection combustion system with a swirl pre-combustion
chamber, a configuration that provides controlled combustion
characteristics, reduced mechanical noise, and dependable cold-starting
performance.
The three-cylinder configuration offers an effective balance between
compact dimensions and operational smoothness, exhibiting less inherent
vibration than a two-cylinder design. Its square bore and stroke
contribute to balanced mechanical forces and a broad torque curve.
Constructed with a substantial cast iron block and a gear-driven valve
train, the S3E2 emphasizes durability and serviceability. It serves as a
robust prime mover for medium-duty industrial, agricultural, and power
generation equipment where increased output over the base S3E model is
required without a fundamental redesign.
Manufacturer: Mitsubishi Heavy Industries, Ltd.
Engine Model: S3E2.
Engine Type: 4-cycle, water-cooled, vertical inline, indirect injection
diesel.
Aspiration: Naturally aspirated.
Emission Compliance: Manufactured in an era preceding modern emission
protocols; conforms to historical industrial engine standards.
Management System: Mechanical fuel injection with mechanical governor.
Commonly equipped with a Bosch PES4-A series injection pump.
Number of Cylinders: 3.
Bore: 98 mm (3.858 in).
Stroke: 98 mm (3.858 in).
Displacement: 2.217 L (2217 cc) (135.3 cu in).
Compression Ratio: 19:1.
Firing Order: 1-3-2.
Rotation Direction: Counter-clockwise when viewed from the flywheel
side.
Maximum Gross Power Output: 31.3 kW (42.0 hp) at 2,400 rpm
(representative value; output is governed and application-specific).
Maximum Gross Torque: 112 Nm (82.6 lb-ft) at 1,600 rpm.
Rated Speed: 2,200-2,400 rpm for variable-speed applications; 1,500 or
1,800 rpm for constant-speed generator sets. Idle Speed: 700-800 rpm.
The cylinder block is a robust, heavily webbed casting manufactured from
high-strength gray iron. Its design delivers a rigid structural
foundation for the three cylinders, incorporating substantial material
around the cylinder bores and main bearing saddles to contain combustion
pressures and manage internal forces. The cylinder bores are
precision-machined and honed directly into the block material. The
crankshaft is a forged steel component, supported by four main bearings.
This four-main-bearing support system is critical for a three-cylinder
crankshaft, providing necessary stability to manage dynamic loads,
ensure precise alignment, and contribute to the engine's overall
smoothness. Connecting rods are forged steel, fitted with replaceable
precision bearing shells at the crankpin end. The piston pin is a
press-fit in the connecting rod small end. Pistons are aluminum alloy,
designed with a specific crown profile compatible with the indirect
injection swirl chamber. The piston ring pack consists of two
compression rings and one oil control ring.
A single-piece cast iron cylinder head is utilized, secured to the block
with studs and nuts. The head accommodates one intake and one exhaust
valve per cylinder. Valve seat inserts are manufactured from hardened,
heat-resistant alloy to ensure longevity and maintain sealing integrity
under thermal stress. The valve train operates on an overhead valve
(OHV) principle, with the camshaft positioned in the cylinder block. The
camshaft is gear-driven from the crankshaft, providing positive and
maintenance-free timing.
The camshaft actuates the valves via solid pushrods and rocker arms.
Rocker arms are mounted on a stationary shaft fastened to the cylinder
head. Valve clearance is set and maintained by a screw and locknut
adjustment on each rocker arm, a scheduled maintenance procedure. The
cylinder head incorporates the indirect injection pre-combustion (swirl)
chamber for each cylinder, which houses a glow plug for cold starting
assistance.
The engine employs a mechanical, inline pump-line-nozzle fuel injection
system. The system is centered on a Bosch PES4-A or equivalent
multi-element inline injection pump. Core components include a
mechanical fuel lift pump, this injection pump, high-pressure steel fuel
lines, and throttle-type (pintle) injectors. The injection pump is a
jerk-pump design, driven by the engine's gear train. It supplies fuel at
high pressure to nozzles that discharge into the pre-combustion swirl
chamber.
A mechanical centrifugal governor, integral to the injection pump,
regulates engine speed by controlling the position of the fuel rack.
This governor is configurable for all-speed (variable) operation in
industrial machinery or constant-speed operation in generator
applications. Fuel filtration is a two-stage process, involving a
primary sedimentor/water separator and a secondary fine filter.
Lubrication is provided by a forced-feed, full-flow wet sump system. A
trochoid (gear) type oil pump, driven directly from the crankshaft,
draws oil from the sump through a pickup tube equipped with a strainer
screen. Pressurized oil is routed through a full-flow, replaceable
cartridge or canister-type oil filter. After filtration, oil enters the
main oil gallery in the block, supplying the crankshaft main and
connecting rod bearings, the camshaft bearings, and the valve gear via
internal passages and hollow pushrods.
The system is engineered for reliable pressure-feed lubrication to all
critical components. The specified engine oil is API CC, CD, or CF
grade. Total oil capacity is 6.0 liters (6.3 US qt), including the
filter. The oil pan is a stamped steel component.
Cooling is managed by a pressurized, pump-circulated liquid system. A
centrifugal water pump, driven by a V-belt from the crankshaft pulley,
provides forced coolant circulation. System operating temperature is
regulated by a wax-pellet type thermostat. Heat rejection occurs via a
tube-and-fin radiator; the cooling fan is mounted on the engine and is
V-belt driven. The increased displacement necessitates effective heat
dissipation.
The cooling system requires a mixture of ethylene-glycol antifreeze and
clean water. A 50/50 mixture is standard for corrosion protection and
freeze resistance. Total cooling system capacity is 5.5 liters (5.8 US
qt) for the engine side, excluding the radiator and external hose
volume.
| Intake and Exhaust Systems |
Intake System: Consists of an air cleaner (oil bath or dry element) and
a cast iron or aluminum intake manifold. Exhaust System: Comprises a
cast iron exhaust manifold and a downpipe connecting to the equipment's
exhaust silencer.
Electrical System: Operates on a 12V or 24V system. A corresponding
starter motor and alternator or DC generator are fitted. The engine
incorporates a glow plug system for cold starting, controlled by a
key-switch or timer module. An electric stop solenoid or manual cable
acts on the injection pump rack.
Length (Front Face of Block to Flywheel Housing): 661 mm (26.02 in).
Width (Overall): 515 mm (20.28 in).
Height (Overall, from sump to valve cover): 730 mm (28.74 in).
Dry Weight (with standard accessories): 230 kg (507 lb).
Engine Oil Change: Every 250 operating hours. Oil Filter Replacement:
Every oil change (250 hours). Fuel Filter Replacement: Service sediment
bowl daily; replace secondary filter element every 500 hours. Air
Cleaner Element Service: Clean oil bath or replace dry element every
100-250 hours, contingent on operational environment. Valve Clearance
Adjustment: Check and adjust every 500 operating hours.
Coolant Replacement: Drain, flush, and refill every 1,000 operating
hours or annually. Fan Belt Tension Check/Adjustment: Inspect and adjust
tension every 250 hours; replace belts showing signs of wear, glazing,
or cracking. Fuel Injection System Inspection: Have injection pressure,
spray pattern, and pump timing checked by a specialist every 1,500
hours.
Cylinder Head Nuts: Tighten in the specified multi-step crisscross
sequence to a final torque of 108-118 Nm (80-87 lb-ft). Main Bearing Cap
Bolts: 88-98 Nm (65-72 lb-ft).
Connecting Rod Cap Bolts: 69-78 Nm (51-58 lb-ft).
Flywheel to Crankshaft Bolts: 108-118 Nm (80-87 lb-ft).
Fuel Injector Holder: 59-69 Nm (44-51 lb-ft).
Glow Plugs: 15-20 Nm (11-15 lb-ft).
Oil Pan Drain Plug: 39-49 Nm (29-36 lb-ft).
Oil Filter Canister/Cartridge: For a canister, tighten the center bolt
to 25-30 Nm (18-22 lb-ft). For a spin-on filter, hand-tighten plus 3/4
turn after gasket contact.
The Mitsubishi S3E2 engine was deployed in medium-duty industrial and
agricultural equipment that benefited from its increased displacement
and three-cylinder smoothness. Common applications include: Agricultural
Tractors: Utility and medium-power agricultural tractors from Japanese
manufacturers. Construction Equipment: Mid-sized vibratory rollers,
mobile welding generators, air compressors, and concrete mixers.
Generator Sets: Industrial and prime power generator sets in the 25-35
kVA power range.
Pumping Equipment: High-capacity irrigation pumps, industrial transfer
pumps, and firefighting units. Material Handling: Medium-duty forklifts
(4-6 ton capacity) and stationary hydraulic power units. Agricultural
Machinery: Powers implements such as large balers, forage harvesters,
and grain dryers. Marine Applications: Used as an auxiliary generator
drive or as a propulsion engine for small fishing vessels, tugboats, and
passenger ferries.
____________________________________________________________________________________
| Industrial Engines Technical Specifications |
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Outboard Engines Technical Specifications |
