Name: Daihatsu Oil Mist Detection Systems
Brand: Daihatsu Diesel Mfg. Co., Ltd.
Availability: InStock

Patents & Design Grants Patent GB2408798 (UK)
Patent JP3840470 (Japan)
Design JP1212448 (Japan)

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MD-SX — Sensor Type · 2004

Daihatsu MD-SX Oil Mist Detector

First sensor-type OMD in the market — multiple sensor units inserted directly through the crankcase sidewall, one per cylinder. Natural diffusion system — no suction mechanism or drive air/piping required. For low-speed, medium-speed and high-speed diesel engines.

Type Approval — Classification Societies

NK (ClassNK)LR (Lloyd's Register) DNVBV (Bureau Veritas) ABSGL (Germanischer Lloyd) KR (Korean Register)CR CCS (China Classification)CE Marking

Responding to recent requirements from engine builders, Daihatsu developed the MD-SX Oil Mist Detector — a sensor-type detector consisting of multiple sensor units directly inserted via the sidewall of the crankcase and fitted to each cylinder of the diesel engine. The system is controlled by the MD-SX Controller via integrated communication.

Daihatsu MD-SX system overview diagram with controller and sensor units

Natural Diffusion — No Suction, No Pipes

The MD-SX uses a natural diffusion system built on technology Daihatsu has developed over decades, augmented with new techniques. The system requires no sucking mechanism or drive air/piping for mist detection by the sensor units. Detection of mist concentrations is performed by an optical dispersion system in a compact arrangement — contributing to ease of maintenance and greater reliability versus suction-type systems.

Daihatsu MD-SX sensor installation diagram — crankcase sidewall mounting

Flexible System Configuration

Maximum 16 detection points — 8 points per engine for twin-engine installations. The system configuration is flexible, including the controller fitting position. Up to 2 engines can be monitored from a single controller (for land or ship use).

Early Detection of Serious Accidents

The oil mist concentration in the crankcase is constantly monitored. The controller uses key switches and an LCD display for easy operation, with a self-diagnosing function that monitors the overall state including all sensor units. If oil mist concentration rises beyond the set point (due to bearing overheating or any other cause), the device issues an alarm — enabling early detection or prediction of what might otherwise develop into serious engine trouble in low-speed, medium-speed and high-speed diesel engines.

📄 OMD Data Sheet 📘 MD-SX Niigata Engine OMD Guide

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Direct Sensor Insertion

Sensor units inserted directly through crankcase sidewall — one unit per cylinder for precise point monitoring.

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Natural Diffusion

No suction fan, no drive air, no piping required — oil mist diffuses naturally into the sensor detection area.

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Optical Dispersion

Infrared optical dispersion detection in a compact arrangement — reliable, minimal maintenance.

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3-Colour Bar Graph

Controller displays 3-colour bar graph mist level indication for each engine — intuitive at a glance.

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LCD + Key Switch

LCD display and key switch operation on controller — plus self-diagnosing function for overall system state.

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Easy Maintenance

Compact arrangement with no moving parts in sensor unit — significantly easier maintenance than suction types.

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<1s Response Time

Controller response time ≦1 second on alarm condition — instantaneous alarm to monitoring system.

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All Engine Types

Low-speed 2-stroke, medium-speed and high-speed diesel engines — marine and industrial.

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IP55 Protection

Both sensor units and controller rated IP55 — protected against dust and water jets in engine rooms.

MD-SX Technical Specifications
Parameter	Sensor Unit	Controller
Function	Oil mist concentration & mist level output	Mist level indication & alarm monitoring
Detection Points	1 point / 1 unit	Max 16 units / 1 engine (8 units × 2 engines)
Detection Method	Natural diffusion system — continuous	Response time ≦ 1 sec
Detection System / Range	Optical dispersion system	0 ~ 2.0 mg/L
Display / Operation	3-colour LEDs (Power / Alarm / Failure)	3-colour bar graph (mist level) 4-colour LEDs (Run / Pre-Alarm / High Alarm / Failure) LCD display Key switch
Contact Output	—	5 points (AC125V-0.4A / DC24V-2A): 2× Pre Alarm, 2× High Alarm, Failure
Power Supply	Supplied from controller	DC 24V (+30% ~ -25%)
Power Consumption	60 mA max / 1 unit	1.5 A max (internal: 0.5 A)
Protection Class	IP 55	IP 55
Weight	500 g (incl. accessories)	4.0 kg
Paint Colour	Munsell N1.0 (Black)	Munsell N1.0 (Black)
Max Cable Length	Total communication cable sensor-to-controller: less than 150 m (Daihatsu option cables)
Classification	NK, LR, DNV, BV, ABS, GL, KR, CR, CCS — CE Marking

MD-SX Product Images

MD-SX Sensor Unit — Original Spare Stocks

Daihatsu MD-SX sensor unit original spare stock 1

Daihatsu MD-SX sensor unit original spare stock 2

Daihatsu MD-SX sensor unit original spare stock 3

Daihatsu MD-SX sensor unit original spare stock 4

MD-SX II — DOMM · 4-Stroke Exclusive

Oil Mist Monitor DOMM (MD-SX II)

Developed exclusively for 4-stroke engines (low, medium and high speed). Built on the proven MD-SX platform with a patented algorithm that estimates oil mist density in un-sensored compartments using adjacent sensor readings — reducing required sensor count without loss of responsiveness.

Daihatsu Diesel Mfg. Co., Ltd. has supplied oil mist detectors continuously since 1976. The sensor-type MD-SX (developed 2004) mounted its sensor directly into the crankcase — the sensing part sticking into the crankcase to directly measure oil mist density, unlike conventional systems that extract oil mist through piping for measurement.

The MD-SX II advances this further for 4-stroke engines. The medium and high-speed 4-stroke engines have a more compact crankcase than low-speed 2-stroke engines, and are not completely divided by walls — meaning there is a wide open space in the crankcase.

Utilizing this structure, MD-SX II can detect oil mist without dropping responsivity even when the number of sensor units fitted is reduced. The patented algorithm estimates the oil mist density at un-sensored positions based on actual readings from the adjacent sensors on both sides.

Patent-Registered Algorithm: The oil mist estimation function (calculating mist density at un-sensored points from adjacent sensor readings) has been patent-registered in Japan. This significantly reduces sensor count and installation cost for 4-stroke engine installations.

In recent years, for fire prevention on tankers, earlier detection of abnormal oil mist levels in the engine room has been required. The manufacturer further advanced the MD-RSX type into the Oil Mist Monitoring Device (OMM type), which can show a visual display of oil mist levels at the point where they are most likely to generate.

Daihatsu MD-SX II DOMM system diagram with sensor layout for 4-stroke engine

MD-SX II Controller Unit

MD-SX II (DOMM) Technical Specifications
Parameter	Sensor Unit	Controller
Function	Oil mist concentration & mist level output	Mist level indication & alarm monitoring
Detection Points	1 point / 1 unit	Max 16 units
Detection Method	Suction type — continuous	Response time ≦ 1 sec
Detection System / Range	Optical dispersion system	0 ~ 1.2 mg/L
Display / Operation	3-colour LEDs (Power / Alarm / Failure)	3-colour bar graph (auto-shifts to all sensor positions periodically) 4-colour LEDs (Run / Pre-Alarm / High Alarm / Failure) LCD display Key switch
Contact Output	—	5 points (AC125V-0.4A / DC24V-2A): 2× Pre Alarm, 2× High Alarm, Failure
Power Supply	Supplied from controller	DC 24V (+30% ~ -25%)
Power Consumption	230 mA max / 1 set (sensor: 60 mA max)	4.2 A max (internal: 0.5 A)
Protection Class	IP 55 (except fan hood)	IP 55
Weight	Approx. 2.3 kg (sensor unit: approx. 500 g)	4.0 kg
Paint Colour	Munsell N1.0 (Black)	Munsell N1.0 (Black)
Engine Type	4-stroke engines — low, medium and high speed (exclusive)
Key Feature	Patented algorithm estimates mist density at un-sensored positions from adjacent sensor readings

MD-9M — Classic Series · Widely Installed

Daihatsu MD-9M Oil Mist Detector

Part of the long-running MD-9 series that entered service in 1976. Using optical sensors and continuous crankcase monitoring, the MD-9M is installed on hundreds of ships worldwide on Daihatsu DK, DE, DS and DC series engines. Controller Assy Part No: S110800280A.

Since the initial release of the MD-9 model in 1976, Daihatsu Diesel has continuously marketed oil mist detectors with high acclaim from users worldwide. The MD-9 series used micro-electronics technology that was further improved to produce the MD-3M, MD-9M and MD-14M models. Further miniaturization then led to the current MD-SX sensor type.

The MD-9M is a continuous crankcase oil mist monitoring system using optical sensors to detect light scattering caused by oil mist particles. Alarm output is connected to the engine safety shutdown system. Visual indicators (LED and analog meter) display mist levels in each crankcase compartment.

Installed on: Daihatsu DK, DE, DS and DC series engines — both marine propulsion and auxiliary generator sets.

Controller Assy S110800280A: Make — Daihatsu Diesel Mfg. Co. Ltd., Osaka, Japan | Type — MD-9M | Part No — S110800280A. We carry genuine original and surplus stocks in Singapore.

As an authorized Daihatsu OMD distributor, we carry complete units and spare parts for the MD-9M. Our factory-trained workshop team performs full function tests, rebuilds and repairs — with fast replacement for all spare parts.

MD-9M Genuine Parts

Daihatsu MD-9M oil mist detector genuine unit 1

Daihatsu MD-9M oil mist detector genuine unit 2

MD-9M Controller Assy PCB — Surplus & Reconditioned Stocks

Daihatsu MD-9M controller assy PCB surplus stock 1

Daihatsu MD-9M controller assy PCB surplus stock 2

Daihatsu MD-9M controller assy PCB surplus stock 3

Daihatsu MD-9M controller assy PCB surplus stock 4

MD-9M Stepping Motor Assy — Genuine Stock

Daihatsu MD-9M stepping motor assy genuine stock 3

Daihatsu MD-9M stepping motor assy genuine stock 4

Workshop Repair & Rebuild Available: Our technical department has the capability and experience to rebuild and repair all MD-9M spare parts. Our workshop is equipped with all necessary instruments to carry out tests and rebuild complete oil mist detectors, including stepping motor assy, controller PCB and complete unit overhaul. Fast replacement guaranteed.

Daihatsu
Oil Mist Detectors