YC4D90Z‑D25

Model Overview

The YC4D series engines represent Yuchai's classic power products developed through research and development, boasting high brand recognition, market acceptance, and substantial market penetration. The YC4D90Z‑D25 generator set engine exhibits advantages such as reliability, durability, energy efficiency, environmental friendliness, compact structure, strong transient load capacity, and excellent maintainability.

Product Features

• The engine's main structure, including the engine block, has been rigorously tested to ensure the overall high reliability of the unit.
• The cylinder head integrated water outlet manifold design is adopted to reduce sealing surfaces and enhance sealing reliability.
• By employing mature mechanical‑electrical adjustment coupled with high‑efficiency boost technology, the system effectively controls fuel injection volume and ensures adequate air intake, thereby guaranteeing complete combustion and reduced emissions under varying load conditions for diesel engines.
• It demonstrates excellent transient speed regulation capability and high load capacity, meeting the performance requirements of G3 class for generator sets.
• The use of high‑efficiency filter diesel oil filters ensures more reliable operation.

Product Service

Services:玉柴 Yuchai has established the industry's largest service network with the smallest service radius, longest warranty coverage, and fastest response time. The company operates 49 global offices, including 14 overseas offices covering Europe, Africa, and South America. It has partnered with 108 overseas service agents, over 3,000 service stations, and more than 5,000 parts sales outlets to deliver exceptional Jiecheng services to customers.

explain

1、 Prime Power: The basic power (PRP) specified in ISO 8528. When maintenance is performed according to Yuchai's recommended intervals and methods, the engine can operate continuously at variable load output without annual runtime restrictions. The average output power within a 24‑hour cycle must not exceed 70% of the prime power.

2、 Standby Power (ESP): The emergency standby power specified in ISO 8528. Maintenance shall be performed according to Yuchai's recommended intervals and methods. This refers to the maximum power output of a variable power series when the engine operates for 200 hours annually under public grid failures or test conditions. The average output power allowed during a 24‑hour operation cycle must not exceed 70% of the standby power.

3、 The engine power data in the table above were measured under ISO 8528‑1 and ISO 3046 conditions.

4、 The power output of the generator set is calculated based on the assumed efficiency of the AC generator and is provided for reference only.

5. Both kVA and kW values are calculated using a standard power factor of 0.8. 6、 The information provided is current at the time of printing, but may be subject to change after publication.

Note: Diesel density is calculated as 0.835 kg/L.

Technical Parameter

type: .......................................................Vertical, inline, water‑cooled, four‑stroke

Inspiration pattern: ..................................exhaust turbocharging

combustion chamber type: ...Direct injection type construction ω combustion chamber

Number of cylinders‑Cylinder diameter × Stroke: .......................4‑110×125mm

Number of valves per cylinder:.................................................... 2

Total piston displacement: ............................................................4.75L

reduction ratio: ..............................................................................17.5:1

Cylinder type: .................................................................................wet liner

job order:........................................................................................ 1‑3‑4‑2

fuel supply system:......................................................................... mechanical pump

lubricating system: ...........................................................Pressure, splash mixed type

Start‑up method: ...............................................................electric starting

Oil capacity: ......................................................................11.5L

combustion‑air ratio:.......................................................... ≤0.2%

Crankshaft rotation direction: .............Counterclockwise (facing the power output end)

lowest no‑load speed:...................................................... (700～750) r/min

speed regulation performance class: ................................ISO 8528 G3

noise Lp: ............................................................................≤112dB(A)

Total dry weight

engine:.............................................................................. 450kg

Water tank radiator: ...........................................................30kg

The final weight and dimensions of the engine vary depending on specific configurations.

Engine Configuration

➤ induction system

air cleaner

➤ coolant passage

Water tank radiator (customer‑supplied)

➤ electrical installation

24V or 12V electrical system

intake preheater

➤ fuel system

mechanical pump

fuel filter

➤ lube oil system

oil filter

➤ Flywheel and Flywheel Housing

SAE 11.5# Flywheel

SAE 3# Flywheel Housing

➤ document

operating instruction

Installation Guide

Part drawing catalog Fuel grade: Summer: GB 252—2015 Premium or Grade 1 No.0, No.10 regular diesel oil. Winter: GB 252—2015 Premium or Grade 1 No.0, No.‑10, No.‑20, No.‑35 regular diesel oil.

Oil grade: Summer: 15W‑40, Winter: 10W‑30 or other diesel oils with quality grade no lower than CH‑4 level specified in GB 11122‑2006, adapted to environmental conditions.