Yanmar 4D88E Specifications
| Engine Model: Yanmar 4D88E |
| Engine Type: 4-stroke inline 4-cylinder naturally aspirated water cooled diesel |
| Total Displacement: 133.6 cu.in (2.19 L) |
| Rated Engine Power: 47 Hp (35 kW) at 3000 rpm |
| Fuel System Type: Direct injection |
____________________________________________________________________________________
The Yanmar 4D88E is a 4-cylinder, naturally
aspirated diesel engine from the 4D88 series, representing a staple in
compact industrial power generation. This engine is widely utilized in
construction equipment, including Komatsu excavators and skid steer
loaders, as well as agricultural machinery and power generators. The "E"
designation generally refers to an industrial-grade application variant.
Known for its robust cast iron construction and direct injection (DI)
combustion system, the 4D88E prioritizes fuel efficiency, cold-start
reliability, and low-end torque essential for hydraulic machinery
operation. The engine shares its core architecture with the 4TNE88
series and is frequently paired with applications requiring steady
output in confined engine bays, such as mini-excavators and compact
wheel loaders.
The Yanmar 4D88E is a vertical, water-cooled, 4-cycle diesel engine. It
utilizes a direct injection system where fuel is injected directly into
the combustion chamber, optimizing thermal efficiency compared to
indirect injection designs. The engine is naturally aspirated, lacking a
turbocharger, which contributes to its longevity in dusty construction
environments.
Engine Type: Vertical, 4-cycle, water-cooled diesel
Number of Cylinders: 4
Displacement: 2.190 L / 133.6 cu.in
Bore: 88.0 mm / 3.46 in
Stroke: 90.0 mm / 3.54 in
Combustion System: Direct Injection (DI)
Aspiration: Naturally Aspirated
Compression Ratio: 19.0:1
Rated Output (Range): 35-47 hp / 26-35 kW
Rated Speed: 2200-3000 rpm (application-dependent)
Maximum Torque: 135-145 Nm / 100-107 lb-ft at 1600-1800 rpm
Direction of Rotation: Counter-clockwise (viewed from flywheel)
Starting System: 12V Electric starter (1.4 kW or 2.0 kW)
Fuel Injection Pressure: 196-206 kg/cm2 / 2787-2930 psi
Injection Timing: 14° - 16° Before Top Dead Center (application
specific)
The cylinder block is constructed from high-grade cast iron using a
robust, open-deck design intended to withstand the high cylinder
pressures of direct injection diesel combustion. The block incorporates
a deep-skirt configuration for enhanced structural rigidity under
torsional load. The cylinder bores are machined with a plateau-honed
finish and utilize replaceable dry liners in some variants to facilitate
overhaul and rebuild.
Within the block, a forged steel crankshaft is supported by five main
bearings. The connecting rods are forged steel, designed for the high
compression ratio of 19.1:1. The pistons are aluminum alloy castings
with a complex crown geometry optimized for the direct injection swirl.
Each piston is cooled by an oil jet directed from the block, which is
critical for managing thermal stress in continuous operation. The oil
pan is a stamped steel unit with a large capacity to ensure lubrication
on steep inclines encountered in construction.
The cylinder head is a cross-flow cast iron design, chosen for its
thermal stability under sustained high load. It houses the valve train
and the direct injection components. The valve mechanism is driven by a
camshaft located in the cylinder block (typical of industrial diesel
design), utilizing pushrods and rocker arms to actuate the valves. This
configuration prioritizes serviceability and durability over high-RPM
performance.
Valve Configuration: Overhead Valve (OHV), 2 valves per cylinder (8
total)
Valve Clearance (Cold): 0.20 mm / 0.008 in (Intake and Exhaust)
The 4D88E employs a direct injection fuel system. The fuel injection
pump is typically a Bosch-type in-line or distributor-type pump,
mechanically governed to prevent overspeeding. High-pressure steel lines
deliver fuel to the multi-hole injector nozzles seated in the cylinder
head.
The system operates at pressures suitable for effective atomization
within the piston bowl. The mechanical governor adjusts fuel delivery
based on engine load, maintaining stable RPM for generator or hydraulic
pump applications.
Lubrication is provided by a forced feed system using a trochoid pump,
known for its compact size and efficient oil flow. This pump draws oil
from the sump and forces it through a full-flow spin-on cartridge filter
before distributing it to the crankshaft, connecting rod bearings,
camshaft, and rocker arm assembly.
An oil cooler is integrated into the system, utilizing engine coolant to
stabilize oil temperature during peak load cycles typical of excavator
hydraulic operation. The engine oil capacity is substantial to extend
service intervals in dusty conditions.
Engine Oil Capacity (with filter): 7.4 L / 7.8 US qt
Oil Filter Type: Spin-on cartridge
The cooling system is a pressurized, forced circulation design utilizing
a centrifugal water pump driven by the crankshaft via the fan belt.
Coolant is circulated through the cast iron block and cylinder head. A
water-cooled oil cooler is integrated into the coolant circuit. The
system is sealed by a radiator cap rated for standard industrial
pressures to raise the boiling point of the coolant.
A critical element is the raw water pump used in marine versions (4JH
series) or the radiator fan used in industrial versions; the 4D88E block
is shared across both configurations. The water jackets are designed for
high-flow rates to ensure uniform cooling across all four cylinders.
| Intake and Exhaust Systems |
Intake System: The intake system consists of a heavy-duty air cleaner
with a double-element filter (cyclone and paper) suitable for high-dust
environments like construction sites. The intake manifold is designed to
deliver equal air distribution to all cylinders for smooth running.
Exhaust System: The exhaust manifold is a log-style cast iron design,
sturdy enough to support heavy exhaust piping and silencers used in
stationary generator sets.
Timing System: The camshaft and fuel injection pump are driven by a gear
train (idle gear system) from the crankshaft. This gear-driven system is
a hallmark of industrial Yanmar engines, providing precise timing and
eliminating belt or chain replacement intervals typical of automotive
engines. The system includes a fuel injection pump drive gear nut that
requires precise torque setting.
Emissions Control: As a pre-Euro 4 industrial engine, emissions control
is primarily managed through internal engine design (direct injection
optimizing combustion) and mechanical fuel control. Later variants may
incorporate blow-by ventilation systems, but the base 4D88E relies on
precise injection timing rather than after-treatment.
Overall Length: 650 mm / 25.6 in
Overall Width: 550 mm / 21.7 in
Overall Height: 750 mm / 29.5 in
Dry Weight: 200 kg / 441 lbs (varies with flywheel and starter
configuration)
Engine Oil and Filter: Change every 250-500 operating hours or annually.
Engine Oil: Use API CD/CF or higher 15W-40 or 10W-30 oil.
Fuel Filter: Replace every 250 hours or sooner if water is detected in
the sediment bowl.
Valve Clearance (Intake): 0.20 mm (0.008 in).
Valve Clearance (Exhaust): 0.20 mm (0.008 in).
Valve Clearance: Inspect and adjust every 500 hours.
Injection Pressure: Inspect by diesel specialist using a pop tester if
hard starting or excessive smoke occurs.
Cooling System: Flush and replace coolant every 1,000 hours. Use
ethylene glycol antifreeze with corrosion inhibitors.
Cylinder Head Bolts, Step 1: 30-36 lb-ft / 40-50 Nm
Cylinder Head Bolts, Step 2: 60-66 lb-ft / 80-90 Nm
Connecting Rod Cap Bolts: 29-33 lb-ft / 40-45 Nm
Main Bearing Cap Bolts: 72-80 lb-ft / 98-108 Nm
Fuel Injection Pump Drive Gear Nut: 58-65 lb-ft / 78-88 Nm
Crankshaft Pulley Bolt: 135-150 lb-ft / 183-203 Nm
Rocker Arm Shaft Bracket Nuts: 18-22 lb-ft / 25-30 Nm
Injector Hold-Down Nuts: 18-22 lb-ft / 25-30 Nm
The 4D88E engine is extensively used in off-highway equipment, primarily
branded under Komatsu and Yanmar. Due to the corporate relationship
between Yanmar (engine manufacturer) and Komatsu (equipment
manufacturer), this engine appears in "Komatsu 4D88E" specification.
Excavators:
Komatsu PC40MR-1, PC40MR-2, PC40MR-3, PC40MRX-1, PC45MR-1, PC45MR-3,
PC45R-8.
Komatsu PC50FR-1, PC50FR-2, PC50MR-2, PC50MR-3, PC50UD-2, PC55MR-3,
PC58SF-1.
Kobelco B84, CX47, CX50, CX50B, CX55B, SK45SR-2, SK50UR-3, Z75, Z76,
Z84, Z85, Z89.
Hitachi ZX40U-2, ZX40U-3, ZX48U-3, ZX50U-2, ZX50U-3, ZX52U-3.
Takeuchi TB53FR, TB145, TB153FR, TB250.
Case CX47, CX50B.
Yanmar ViO55, ViO50-1, ViO50-2, ViO45, ViO45-5B.
Skid Steer Loaders:
Mustang 1350R, 1500R, 2041, 2044, 2054.
Komatsu SK714, SK714-5, SK815-5.
Gehl KL278, KL398, SL4240, 4240, 4240E.
Generators:
Kohler 19.0EOZ, 20EOZD.
JCB G20RX, G22QX, G22X.
Yanmar YEG230DSLC, YEG230DSLS, YEG230DTLC, YEG230DTLS.
Tractors:
Landini MISTRAL 50, 2-050.
New Holland T3030, E55BX.
Other Equipment:
Hyundai HSL610 Skid Steer Loader.
Komatsu WA50-6 Wheel Loader.
Komatsu CD30R-1, CR30R-1 Tracked Dumpers.
Husqvarna FS4800D Concrete Saw.
Gehl AP1648 Paver.
____________________________________________________________________________________
| Industrial Engines Technical Specifications |
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Outboard Engines Technical Specifications |
