ABC DZC Engine: Medium-Speed Marine Diesel

The ABC DZC is a medium-speed four-stroke marine diesel engine built by Anglo Belgian Corporation (ABC) at its Wiedauwkaai factory in Ghent, Belgium. The engine has a 256 mm bore and 310 mm stroke, runs at 720 to 1,000 rpm, and covers a power band from 1,032 kW in the six-cylinder inline to 4,000 kW in the 16-cylinder vee-bank configuration. It’s the volume engine of the ABC catalog, introduced in the 1980s out of the engineering programme that followed ABC’s 1973 licence from SEMT-Pielstick, and it remains in production as of 2026 with successive updates for emissions compliance, biofuel capability, dual-fuel methanol operation, and, through the BeHydro joint venture with Compagnie Maritime Belge, hydrogen combustion. Related performance calculators include the Brake Mean Effective Pressure calculator and the Mean Piston Speed calculator.

Origin and development

ABC built its pre-DZC range on the DX and DXC platforms: 242 mm bore, naturally aspirated through to turbocharged-and-intercooled, with power topping out well below 1,000 kW per engine. Those were the right engines for a 1960s inland-waterway fleet running barges of modest tonnage on the Rhine, the Scheldt, and Belgium’s canal network. By the 1970s the fleet was growing in capacity and the market wanted engines that could push bigger push-tug convoys and drive larger dredgers.

The 1973 licence from SEMT-Pielstick of France, covering the PA4 engine design, gave ABC access to a higher-output medium-speed platform at a moment when the company’s own engineering could not have reached there alone. The PA4 was already running in ocean-going vessels and land power plants across Europe, and the licence brought that experience into the Ghent drawing office. What came out of that period was the DZC: a new bore family at 256 mm, up from the DXC’s 242 mm, on a 310 mm stroke, turbocharged and intercooled as standard, with a rated speed range up to 1,000 rpm. The company’s 1980s histories describe the DZC as delivering “double power from almost the same cylinder volume,” which is an overstatement, but the direction is right: the combination of a slightly larger bore and higher turbocharger boost allowed ABC to roughly double the output per unit of installed length compared with its previous top-of-range inline engine.

The DZC designation follows ABC’s air-system suffix convention, which the company has used since the DX generation. The D prefix denotes diesel. The Z denotes the generation within the medium-bore family. The C suffix denotes turbocharged and intercooled. A later generation, the DZD, uses the D suffix to signal updated injection and control technology suited to the dual-fuel and alternative-fuel configurations that emissions rules made necessary from the 2010s onward. Both the DZC and DZD share the same bore, stroke, and basic block architecture.

The SEMT-Pielstick connection

The PA4 influence on the DZC is visible in the architecture. The PA4 was a single-acting trunk-piston four-stroke with direct fuel injection, a layout that Pielstick had refined through the 1950s and 1960s for fast ferry and patrol-vessel propulsion at speeds between 750 and 1,000 rpm. ABC kept that basic configuration and adapted it for the longer-service, lower-peak-load duty cycle of the European inland and small-coastal market. The compression ratio on the DZC, at 12.1:1, is lower than the PA4’s peak, and the BMEP of 18.8 bar at the top 1,000 rpm rating is conservative by the standards of mid-1980s medium-speed design. That conservatism was deliberate and has been a constant in ABC’s engineering stance through every subsequent development.

Brake mean effective pressure is the useful measure of how hard a given swept volume is worked: the higher the BMEP, the more power per litre of displacement, but also the higher the peak cylinder pressure, the higher the thermal load on pistons and liners, and the shorter the interval before overhaul. The DZC at 18.8 bar versus, say, the Wartsila 20 series at its top ratings trades weight and displacement against maintenance intervals. An inland-waterway barge operator who expects to run an engine for 30,000 to 50,000 hours before a major overhaul, with no quick access to a specialized service port, values the conservative rating in a way that a fast-ferry operator does not.

Mechanical architecture

The DZC is a single-acting trunk-piston engine with four strokes per cycle: the piston skirt carries the side-load directly to the liner wall, eliminating the crosshead and stuffing box that slow-speed two-stroke engines require, which keeps the engine compact enough to fit in a barge machinery room.

Each cylinder has one jerk-type injection pump, driving a multi-hole injector. The injection system is mechanically governed on the base DZC specification; later DZD variants with common-rail injection moved the metering and timing to electronic control, which is necessary for the precise fuel-split management in dual-fuel operation. The block is cast iron, with wet cylinder liners that can be removed and replaced without boring the block, which matters for a builder whose service model is long-life and in-situ overhaul rather than exchange of short-life units.

ABC fitted anti-polishing rings to the DZC from 1993. The anti-polishing ring sits at the top of the liner bore and physically limits the maximum diameter reached by the piston crown land, preventing the progressive glazing of the bore surface that leads to rising oil consumption and deteriorating combustion. The move was an early adoption: it was driven by the same concern for very long liner life that informed the conservative BMEP target. Together, the anti-polishing ring and the 18.8 bar ceiling are the two most concrete expressions of the engine’s design philosophy.

The crankshaft is a one-piece forging, fully counterweighted, running in plain shell bearings with forced lubrication from a gear-driven pump. The turbocharger on the inline six and eight is a single axial-flow unit, mounted at one end of the engine. At the V16 rating the turbocharging arrangement is more complex: four turbochargers serve the 16-cylinder bank, a layout forced by the exhaust-gas volumes at 4,000 kW and the need to keep the engine within a buildable length for a barge or generator-set enclosure.

Compression ratio and fuel injection

The compression ratio of 12.1:1 is modest. Modern medium-speed engines of the same bore class can run 14:1 to 16:1, which improves thermal efficiency and reduces the ignition-delay problem with low-cetane fuels. ABC kept the lower ratio for two reasons. First, the lower peak pressure reduces the fatigue load on the cylinder head, connecting rod, and main bearings, extending their life in exactly the duty cycle ABC’s customers run. Second, the lower ratio makes the engine more tolerant of variable fuel quality, which matters for an inland-waterway operator whose bunker supply at a Rhine terminal may not match the quality at a well-serviced ocean port.

Direct injection through a jerk pump per cylinder is straightforward to maintain with generic tooling. The jerk pump is a self-contained positive-displacement unit driven off the camshaft; its delivery can be checked and adjusted without removing the engine or connecting a laptop to a proprietary diagnostic system. That simplicity is part of the ABC service proposition for the many DZC engines still running on vessels whose crews include a skilled mechanic but not a factory-trained technician.

Configurations and rated power

The DZC family spans four standard cylinder arrangements, all sharing the 256 mm bore and 310 mm stroke.

Power figures are at the crankshaft flywheel under ISO 3046 standard reference conditions. The special-application duty points marked with an asterisk in ABC’s datasheets, the -188 rating steps in the model number, reach the higher end of each range and are quoted for controlled installations with guaranteed cooling and intake conditions. The standard rating steps, -166 in the model encoding, are the duty points ABC offers for general marine and genset use without project-specific guarantees.

At 1,000 rpm the mean piston speed of the inline eight is 10.3 m/s, calculated as twice the stroke times the speed in revolutions per second: 2 × 0.310 m × (1,000/60) = 10.3 m/s. That figure is at the upper end for a medium-speed engine of this bore but is well within the design range for a medium-speed four-stroke engine designed for continuous-duty service. The same engines are often run at 750 or 900 rpm in propulsion duty, where the lower mean piston speed buys additional liner life between overhauls; many propeller-drive installations use a reduction gearbox to bring the shaft speed down to the 300 to 450 rpm range that a fixed-pitch propeller needs.

Reading the DZC model number

ABC encodes rated speed and rating step into the model designation. A 6DZC-1000-188 is a six-cylinder DZC, rated at 1,000 rpm, at the -188 (special-application) rating step. A 8DZC-750-166 is an eight-cylinder, 750 rpm, standard rating. The middle number is the crankshaft speed in rpm; the trailing three-digit number identifies the rated mean effective pressure family within the engine. The Marine Engine Model Decoder can parse ABC designations alongside Hanshin, Akasaka, Yanmar, and Wartsila schemes.

The V in 12VDZC or 16VDZC denotes the vee-bank configuration, distinguished from the inline variant. Some ABC literature omits the V and writes 12DZC to mean the V12; the inline DZC only goes to eight cylinders, so ambiguity is rare in practice but the V prefix is the precise form.

Generator-set ratings

For power-generation duty, the same engines are quoted at the alternator shaft rather than the crankshaft. The 8DZC-1000-188 produces 2,000 kW mechanical at the flywheel, which the ABC catalog converts to 1,900 kW electrical at 50 Hz three-phase, assuming a generator efficiency of 0.95. That translates to 2,375 kVA at a 0.8 power factor. The 6DZC-1000-166 at 1,500 kW mechanical delivers about 1,425 kW electrical. The 16VDZC-1000-188 at 4,000 kW mechanical delivers around 3,800 kW electrical.

Multi-engine arrays of V16 DZC units are the path to larger plant outputs. The Congo-Brazzaville power station commissioned in 2009 uses ten 16-cylinder V-DZC engines totaling 32 MW, which is the reference case ABC publishes for the configuration. Each unit contributes a little over 3 MW electrical, and the array steps power up and down as demand requires by running varying numbers of sets rather than throttling individual engines below efficient part-load points.

Marine applications

The DZC found its core market in the propulsion of inland-waterway vessels: self-propelled barges, push-tug convoys, small tankers, and passenger vessels operating on the Rhine, the Scheldt, the Maas, the Rhine-Main-Danube Canal, and their connected Belgian and Dutch waterway networks.

These vessels have specific propulsion requirements that suit the DZC well. The duty cycle is not continuous high-load ocean steaming; it’s a mix of full-power against the current, part-load on straight reaches, slow speed through locks, and frequent stops and maneuvers. An engine designed for long life at moderate load, with good part-load efficiency and rugged mechanical simplicity, is the right match. The variable-speed gensets and direct shaft drives favored on inland craft are also better suited to a medium-speed engine than to a slow-speed two-stroke, which doesn’t want to run below about 60% of its rated speed without combustion quality problems.

Pusher tugs and the Rhine convoy system

Pusher tugs on the Rhine and the Belgian canal system commonly fit two DZC or V-DZC engines per vessel, one per shaft, with the two shafts driving either twin fixed-pitch propellers or, in more recent builds, controllable-pitch units behind nozzles. The twin-engine arrangement gives a redundancy that a single larger engine does not: an engine failure leaves the vessel mobile at half power, enough to reach a mooring or complete an approach to a lock. The convoy system on the Rhine, where a push-tug drives a string of barges carrying several thousand tonnes of cargo, means the propulsion reliability requirement is high; a breakdown in a lock approach is a serious incident.

Typical power for a Rhine push-tug is 1,000 to 2,000 kW per shaft, which falls precisely in the inline DZC range. A two-by-8DZC-1000-166 installation at 1,720 kW per engine gives about 3,440 kW total, enough for a loaded convoy on the middle and lower Rhine. On the upper Rhine, where current speeds are higher, the same vessel might need the special-application rating, replacing one of the 166-step engines with a 188-step unit at 2,000 kW.

Tugboats for port and canal service

Port and canal tugs require bollard pull, which depends on the thrust delivered at low speed rather than shaft power alone. The DZC on a fixed-pitch nozzle propeller, or a controllable-pitch propeller inside a ducted nozzle, is the standard solution for European river and canal tugs in the 200 to 500 kW bollard-pull range. The tug operations and bollard pull article covers the relationship between installed power, propeller selection, and achievable bollard pull in detail.

ABC has supplied DZC engines to Belgian and Dutch port tugs, canal service vessels, and icebreaking assists on the Rhine and Belgian waterways. The single-engine installation, with one DZC driving one fixed-pitch propeller in a kort nozzle and a bow thruster for lateral control, is common on canal tugs under about 500 kW.

Dredging vessels

Dredging is the application where the DZC’s durability argument is clearest. A dredger works in continuous duty, often 20 hours per day, in harsh conditions with abrasive water, variable loads as the pump cycles on and off, and no easy port access for a major engine repair. Trailing suction hopper dredgers, grab dredgers, and cutter suction dredgers all need reliable medium-speed prime movers with long overhaul intervals and high tolerance for variable load.

The DZC’s conservative BMEP and the anti-polishing liner rings translate directly into lower maintenance cost per dredging hour. Belgian and Dutch dredging contractors, operating globally but maintaining engines out of Ghent-area workshops, have historically favored ABC engines partly for the service proximity and partly for the parts availability that a continuously produced engine series guarantees over a working life of 25 to 40 years.

Fishing vessels

Dutch and Belgian beam trawlers and seine-netters were an early DZC market. These vessels work in the North Sea and the eastern Atlantic, in conditions that are harder on engines than the sheltered inland waterways, and the propulsion duty alternates between full power steaming to the grounds, intermediate speed towing, and slow-speed hauling and sorting operations. The DZC’s ability to run across the full speed range without combustion instability, combined with its mechanical simplicity for a crew that is its own service crew, made it a preferred engine for the 400 to 1,000 kW trawler class.

Short-sea coasters and small ferries

Coastal vessels from about 500 to 3,000 tonnes deadweight, operating on European short-sea routes: Belgium to the UK, the Netherlands to Scandinavia, the Baltic feeder trade. These vessels need more power than an inland barge but less than a large coaster or a medium-haul ro-ro. The inline eight-cylinder DZC at 1,720 to 2,000 kW sits in the right bracket, and the V-DZC configurations extend coverage to small ferries and passenger vessels in the 2,000 to 4,000 kW propulsion range.

Navy and patrol vessels

ABC supplies navy applications for European navies and coast-guard services that prefer a European-sourced, nationally supportable engine in the 1,000 to 3,000 kW range. Navy procurement in Belgium and the Netherlands has used ABC engines for patrol vessels, minelayers, and logistics ships where the medium-speed configuration gives a better specific weight and lower signature than a slow-speed engine. ABC markets the DL36 for larger navy vessels; the DZC is the choice for patrol craft and auxiliary vessels under about 3,000 kW.

Rail traction applications

The DZC’s second-largest market after marine propulsion is locomotive traction, where the same block, crankshaft, and fuel system drive the diesel-electric or diesel-hydraulic power units of shunting locomotives and light mainline diesel units.

Rail traction demands a different operating envelope from marine propulsion. The locomotive engine accelerates frequently from idle to full power, spends significant time at low load during station-yard work or signal holds, and must respond quickly to traction demands without the inertia buffer that a ship’s propeller and hull provide. The DZC handles this profile because the medium-speed four-stroke architecture is intrinsically better at handling rapid load changes than a slow-speed engine, and the conservative cylinder loading leaves enough thermal headroom to absorb the transient peaks without forcing pre-derating at high ambient temperatures.

Belgian and Dutch national railway operators have used ABC engines for locomotive repowering, the replacement of an aging diesel engine on an existing locomotive frame with a modern, emissions-compliant unit. Repowering is economically attractive when the locomotive’s mechanical structure is sound but its original engine no longer meets emissions rules or is no longer supportable for parts. The DZC’s rated-speed range to 1,000 rpm, its compact dimensions relative to its power, and its European supply chain for parts all favor it in the repowering market.

The inline six-cylinder DZC at 1,032 to 1,500 kW covers the shunting and light traction range; the inline eight at 1,376 to 2,000 kW reaches the medium mainline diesel class. For the heaviest diesel-electric locomotives, the V-DZC configurations at 2,000 to 4,000 kW are in the right band.

The economic logic of cross-market reuse is clear at this scale. ABC amortizes the development cost of one bore family across marine, rail, and stationary duty, keeping the same block, crankshaft, and cylinder hardware across all three. Only the cooling, mounting, exhaust, and control systems change between a barge installation and a locomotive installation. That shared parts base means that a locomotive operator drawing on the same ABC parts inventory as a barge operator is getting parts that are supported by a much larger installed base than a locomotive-specific engine would be.

Land-based power generation

The DZC and V-DZC serve the land-based generator-set market in the 1,000 to 5,000 kW range for a single unit, and in arrays up to about 30 MW. Applications include prime-power plants for industrial sites and remote communities, standby generators for critical infrastructure (hospitals, data centres, nuclear-station emergency supplies), and combined heat and power (CHP) plants in district heating systems.

The generator-set duty profile differs from marine propulsion in a way that plays to the DZC’s strengths. A standby genset may sit idle for months at a time, then start and reach full load within 30 seconds in an emergency. A prime-power plant in an industrial site runs at near-constant load 8,000 hours per year, closer to the continuous-rating marine case. Both suit the DZC better than a high-speed engine, whose shorter service life and higher running costs per kilowatt-hour at partial load make it less attractive where the genset is expected to run for 20 years without a major overhaul.

The Congo-Brazzaville power station is the most-cited ABC reference in this segment. Ten V16 DZC engines at just over 3 MW electrical each, commissioned in 2009, supply 32 MW to the Brazzaville grid. The project was won partly on fuel flexibility: the plant can run on heavy fuel oil when light distillates are expensive or unavailable, which is a real operational advantage in a landlocked equatorial city where fuel supply chains are not as reliable as in a European port.

Emissions compliance and the CCNR-2 / IMO Tier II baseline

The DZC’s introduction in the 1980s preceded both the IMO NOx tier framework and the European Union’s non-road mobile machinery emissions directives. The engine was designed to the engineering standards of its time, which were adequate for the relatively tolerant limits of the 1990s. The first major regulatory pressure came from the Central Commission for the Navigation of the Rhine, the CCNR, whose Stage 2 standard (CCNR-2) applied to inland-waterway engines from 2007 and set NOx plus HC limits, PM limits, and a 50-hour test cycle designed to capture the variable-speed operation of barge engines.

ABC updated the DZC to meet CCNR-2 through combustion optimization, injection timing adjustment, and turbocharger upgrade, without requiring selective catalytic reduction (SCR). The avoidance of SCR is a genuine commercial advantage for an inland-waterway engine: an SCR system requires a urea (AdBlue) dosing system, a urea tank, a catalyst substrate that needs periodic regeneration or replacement, and additional controls. On a barge with a small engine room and a small crew, the simpler the exhaust system, the lower the maintenance burden.

IMO MARPOL Annex VI Regulation 13 applies to marine vessels on international voyages and sets the NOx Tier II limit at approximately 9.4 g/kWh for engines running between 130 and 2,000 rpm (the exact limit is calculated as 44 × n^(-0.23) where n is rated speed in rpm, so at 1,000 rpm the Tier II limit is 9.4 g/kWh). The DZC at its baseline specification meets Tier II, which applies to vessels built from 2011 onward. The older Tier I limit, at about 12.3 g/kWh at 1,000 rpm, applied from 2000; ABC’s DZC updates through the 2000s were timed to bring the engine within Tier I without hardware changes that would have forced a costly re-certification campaign.

IMO Tier III cuts the NOx ceiling inside Emission Control Areas to roughly 2.0 g/kWh at 1,000 rpm, about a fifth of the Tier II level. Meeting Tier III from the base DZC is not possible with combustion alone; it requires either selective catalytic reduction (SCR) downstream or a radical change in the combustion process. The DL36, ABC’s larger engine launched in 2012, was designed to meet Tier III at source using Miller-cycle valve timing and exhaust gas recirculation; the DZC in its standard form requires SCR for Tier III operation in ECAs.

EU Stage V and the particulate number requirement

The EU Stage V regulation, applied from 2019 to 2021 for new inland-waterway engines, added a particulate number (PN) limit on top of the existing particulate mass (PM) and NOx ceilings. The PN limit is new territory for compression-ignition engines: it counts the number of particles in the exhaust, not just their total mass, which means that an engine can have low PM by mass but still fail PN because it emits many very small particles. Meeting PN typically requires a particulate filter, either a diesel particulate filter (DPF) in the exhaust or a change in combustion that avoids producing fine particulates in the first place.

ABC’s methanol dual-fuel DZD engine, which is the current production variant offered for EU Stage V inland-waterway certification, meets the PN limit because methanol combustion produces dramatically fewer carbon soot particles than diesel combustion. The after-treatment package ABC offers with the methanol DZD, which includes oxidation catalyst stages for the remaining diesel pilot injection, handles the residual PM and PN from the diesel fraction. The result is a fully certified Stage V package without a diesel particulate filter, which again avoids the DPF’s maintenance burden on a barge.

Dual-fuel and alternative-fuel development

The DZD designation, the later generation of the DZ bore family with electronic injection and updated control, covers the alternative-fuel variants. The DZD family uses the same 256 mm bore and 310 mm stroke as the DZC, with the key difference being the addition of a gas-admission or methanol-admission system in the intake or cylinder, a second fuel rail alongside the pilot diesel system, and electronic engine management to control the fuel split across the load range.

Natural gas dual-fuel

The earliest dual-fuel DZD variant burns compressed natural gas (CNG) or liquefied natural gas (LNG) as the primary fuel, with a small diesel pilot injection to ignite the premixed charge. The pilot quantity is typically 5 to 10% of the total fuel energy on a mass basis, enough to provide reliable ignition under all load conditions. On CNG, the pilot diesel can be biodiesel or HVO, keeping the carbon footprint low across both fuel streams.

Natural gas dual-fuel is attractive on the Rhine and North Sea routes where LNG bunkering infrastructure exists: in Rotterdam, Antwerp, Amsterdam, and the major Rhine ports, LNG ship-to-ship and truck-to-ship bunkering has been in commercial operation since around 2015. The DZD on LNG can reduce CO2 emissions by about 20% against the equivalent diesel-only rating, methane slip from incomplete combustion being the main caveat that limits the life-cycle benefit in the GHG accounting done under EU inland-waterway regulations.

Methanol dual-fuel

The methanol dual-fuel DZD is the most recent and most ambitious alternative-fuel variant in the base DZC bore family. Methanol is a liquid at ambient conditions, which simplifies the fuel handling compared with LNG; it can be bunkered through a modified diesel fuel system, and its energy density per litre (about 15.6 MJ/litre against diesel’s 34.4 MJ/litre) requires a roughly 2.3 times larger tank for the same range, but on an inland barge with fixed routes and regular bunkering opportunities, that tank size is manageable.

The methanol DZD runs on up to 70% methanol by energy content with 30% biodiesel or HVO as the pilot fuel, with automatic switchover to 100% biodiesel or HVO on methanol unavailability. It’s rated to 2,652 kW at 1,000 rpm in the 16-cylinder vee configuration. ABC claims a CO2 reduction of up to 70% against fossil diesel when the methanol is sourced from renewable feedstocks, which lines up with the well-to-wake accounting done under the EU FuelEU Maritime regulation and the MARPOL CII framework.

The methanol engine meets IMO Tier II, IMO Tier III, and EU Stage V with ABC’s own after-treatment system. Meeting Tier III on methanol is easier than on diesel because the lower flame temperature in methanol combustion (methanol burns cooler than diesel at the same load) reduces the thermal NOx production rate, and the absence of carbon soot simplifies the particulate compliance. The methanol as a marine fuel article covers the fuel’s properties, bunkering infrastructure, and safety requirements in more detail.

HVO and biofuel compatibility

The entire DZC and DZD range is rated to run on hydrotreated vegetable oil (HVO), also known as renewable diesel, as a drop-in replacement for marine gas oil with no hardware modification. HVO meets EN 15940 paraffinic fuel standards, has a cetane number typically above 70 (versus 45 to 55 for conventional marine gas oil), and reduces lifecycle CO2 by 70 to 90% against fossil diesel depending on feedstock. For an inland-waterway operator who cannot yet access LNG or methanol bunkering, HVO is the lowest-friction path to reducing fleet carbon intensity under EU reporting obligations.

ABC also certifies the DZC range for vegetable oils and animal fats (waste-derived oils), a fuel-flexibility claim that reflects the Ghent location and the proximity of Belgian and Dutch agricultural and food-processing industries that generate waste fats as a by-product. Running on waste-derived fats requires filtered, heated fuel with a low water content, which demands pre-treatment infrastructure that not every installation can provide, but the certification is genuine and matters to operators in regions where waste-fat availability is reliable.

BeHydro: the hydrogen combustion programme

BeHydro is a joint venture between Anglo Belgian Corporation and Compagnie Maritime Belge (CMB), the Antwerp-based shipping and industrial conglomerate, established to develop, manufacture, and supply hydrogen-combustion engines for marine, rail, and power-generation applications.

The joint venture was announced and became operational in the 2010s. CMB had been developing hydrogen-combustion technology through its CMB.TECH research arm, and ABC brought the engine platform, the manufacturing capacity, and the service network. The DZ(D) bore family, 256 mm bore and 310 mm stroke, is the base for every BeHydro engine, which means that BeHydro engines share the cylinder liner, crankshaft, connecting rod, and injection hardware with the commercial DZC and DZD production engines.

BeHydro engine variants

BeHydro produces four inline and vee-bank hydrogen engine variants, offered in both mono-fuel hydrogen and dual-fuel (hydrogen-diesel) configurations:

The hydrogen-combustion approach is different from a hydrogen fuel cell. BeHydro engines burn hydrogen in the cylinder by spark ignition or by a small diesel pilot, using the existing reciprocating-engine thermodynamic cycle. This preserves the manufacturing simplicity of a piston engine and allows a dual-fuel fallback to diesel when hydrogen is unavailable. The downside is that nitrogen-oxide emissions are not zero: hydrogen combustion at high temperature still produces thermal NOx from nitrogen in the air, so a BeHydro engine needs after-treatment to meet NOx limits just as a diesel does. Mono-fuel hydrogen operation eliminates CO2 from the exhaust entirely, and the claim of 100% CO2 reduction is accurate for the tailpipe; the lifecycle figure depends on how the hydrogen was produced.

Dual-fuel hydrogen mode cuts CO2 by up to 85%, with the remainder coming from the diesel pilot fraction. Both modes require the vessel or plant to have a compressed hydrogen storage system and a fuel management system capable of handling hydrogen safely, which is a significant design requirement for a vessel or locomotive that was not originally built for hydrogen.

BeHydro installations: Japan and the tugboat reference

The most cited BeHydro installation is Japan’s first hydrogen dual-fuel tugboat, a project involving CMB.TECH’s Compagnie Maritime Belge and its Japanese distribution partners DAIHATSU INFINEARTH and JPNH2YDRO. The Japanese project uses a BeHydro 8-cylinder DZ(D) H2 engine in dual-fuel mode, demonstrating the technology in a short-sea and port environment where green hydrogen supply is being developed alongside the vessel. The use of Daihatsu Infinearth as a distribution partner is notable: it connects the BeHydro technology to the Japanese coastal and harbor tug market through a well-established local distribution and service network.

The choice of a tugboat as the demonstration platform is logical. Tugs work in ports where hydrogen bunkering infrastructure can be concentrated, they operate short daily cycles that suit the current limitations on hydrogen storage volume per vessel, and they’re visible to port authorities and flag states who need to see the technology in operation before certifying it more broadly.

BeHydro holds distribution agreements with DAIHATSU INFINEARTH for the Asian market and has confirmed installations beyond the single Japanese reference case, though ABC and CMB have not disclosed a fleet count or a production volume for the hydrogen engines.

Hydrogen and the NOx management challenge

The hydrogen combustion engine’s NOx challenge is worth stating precisely. A diesel engine produces NOx through two mechanisms: thermal NOx from high-temperature combustion, and fuel-bound NOx from nitrogen compounds in the fuel. Hydrogen fuel contains no nitrogen, so fuel-bound NOx is eliminated; but hydrogen burns hotter than a diesel-air mixture at the same air-to-fuel ratio, which increases the thermal NOx rate. The net effect depends on the combustion design: lean-burn strategies, which dilute the charge with excess air to bring flame temperature down, can reduce NOx significantly, but they reduce power density and require a larger engine for a given output. BeHydro engines with selective catalytic reduction (SCR) can meet IMO Tier III NOx limits in both hydrogen and dual-fuel modes.

The SCR system on a hydrogen-burning engine doesn’t need to handle carbon soot, which eliminates the DPF regeneration cycle and simplifies the system maintenance. The urea (AdBlue) consumption is also lower because the NOx concentration in the exhaust is lower on average than for diesel at equivalent load, reducing the operational cost of the after-treatment.

Service and overhaul model

ABC’s service model for the DZC is built around the assumption that the engine will run for 25 to 40 years in a single installation, with multiple major overhauls during that life. The major overhaul interval on a DZC in marine propulsion duty at moderate load is typically 20,000 to 30,000 running hours, depending on oil analysis results and the operator’s maintenance practices. An engine commissioned in 1990 on a Rhine push-tug is today at about 200,000 to 280,000 operating hours if it has run a normal barge schedule, and it will likely have had two or three cylinder-head, piston, and liner renewal campaigns in that time.

ABC operates a direct service capability from Ghent and supports the European market through a network of regional partners in the Netherlands, Germany, and France. The geographical concentration of the inland-waterway market in the Rhine-Scheldt corridor makes this practical: a service van from Ghent can reach most of the Rhine between Antwerp and Cologne in a day’s drive, which is the relevant service footprint for a barge operator running between the Belgian ports and the Ruhr or Basel.

Parts availability for the DZC is sustained through continuous production. The bore, stroke, and basic block of the DZC have not changed since the engine’s introduction; a cylinder liner or connecting rod ordered in 2026 fits an engine built in 1988. That parts-backward-compatibility is not accidental: it is one of ABC’s explicit design commitments, and it is reflected in the conservatism of the block design. A redesign that delivered 5% more power but required new pistons and liners would be commercially counterproductive for a maker whose installed base is a major fraction of its revenue.

The test-bed capacity at Wiedauwkaai supports not only new-build acceptance tests but also post-overhaul proving runs. An eight-cylinder DZC block back from a complete overhaul, with new pistons, liners, bearings, and injectors, runs a full-load acceptance test before it returns to the vessel. The test data, including SFOC, exhaust temperatures, and vibration, goes into the engine’s service record and establishes the baseline against which the next service interval’s performance is compared. That continuity of data is part of the value ABC delivers to operators who keep engines for 30 years.

Spare parts and long-life support

For the inland-waterway and rail traction markets, parts commonality across engine generations is a procurement advantage. A port authority or railway company that runs a mixed fleet of 6DZC and 8DZC engines can hold a single parts inventory across both variants, since the cylinder components are interchangeable between cylinder counts and the major wearing parts differ only in the connection-rod set and crankshaft journal count. That inventory simplification reduces the working capital tied up in spares and lowers the risk of being caught without a part at a critical moment.

ABC manages long-term parts supply through direct manufacturing for the core wearing parts (liners, pistons, rings, bearing shells) and through European sub-suppliers for the auxiliary items (injectors, turbochargers, cooling-pump seals). The turbocharger used on the DZC is a sourced component from established European turbocharger makers, which means parts are available through the turbocharger manufacturer’s own service network as well as through ABC, providing redundancy in the supply chain that a barge operator in a remote river port can rely on.

Competitive positioning

The DZC sits in a bore class and speed range where its main competition comes from Caterpillar’s 3500 series (bore 137 mm, high-speed, rated up to 1,432 kW in marine configuration), the MTU Series 2000 and 4000 (bore 130-165 mm, high-speed), and for the larger V-DZC configurations, the lower ratings of the Wartsila 20 (bore 200 mm) and the Himsen H21/32 series.

The competitive trade is consistent across all these comparisons. Caterpillar and MTU offer lighter engines per kilowatt, faster speed, and a global service network with more branches and faster parts. ABC offers a longer overhaul interval, simpler mechanical design, European sourcing, and a service network concentrated precisely in the Rhine-Antwerp-Rotterdam triangle where most DZC engines work. An inland-waterway operator in Antwerp or Duisburg is closer to ABC’s Ghent factory than to the nearest Caterpillar or MTU service depot capable of a major overhaul on a 2,000 kW engine, and for a barge running a tight schedule, proximity to service matters more than the weight difference between a DZC and a Cat 3516.

Against the Wartsila 20 series (200 mm bore, 280 mm stroke, 1,000 rpm, up to 4,350 kW in twelve cylinders), the DZC is a larger-bore, lower-BMEP engine at a similar rated speed. The Wartsila 20 is more widely deployed globally and has a deeper service infrastructure across ocean-going vessels, which is where most Wartsila 20 engines work. In the specific segment of European inland-waterway propulsion, the DZC holds its own on service and parts economics.

Against the Himsen H21/32 (210 or 320 mm bore variants, broadly comparable speed range), the comparison is more geographic: Himsen by Hyundai Heavy Industries is strong in Korean-built tonnage and in Asian markets, while ABC has held the European inland market through the relationships and service proximity that a Korean maker cannot easily replicate from Seoul.

Limitations of this article

The technical figures in this article are drawn from ABC datasheets and the company’s published history. ABC reserves the right to alter specifications without notice, as stated on its datasheets, and the exact power ratings at specific duty points reflect standard reference conditions that may not match every installation. The special-application ratings (the -188 steps) are quoted for controlled conditions and should not be assumed as the default for a project without confirmation from ABC.

ABC does not publish production volumes, fleet counts, or revenue. Claims about the number of DZC engines in service, or the installed base’s age distribution, are inferred from the company’s published history rather than disclosed data. BeHydro installation counts beyond the Japan tugboat reference are not publicly disclosed as of mid-2026.

The DV36 (vee-bank version of the DL36) was announced at the 2012 DL36 launch with targets above 10 MW; its production status had not been confirmed in ABC’s published materials as of the time this article was written. Where V-DZC vee-bank figures appear here, they are taken from the datasheet; where DV36 figures appear, they are the 2012 launch targets.

Emissions certification details, particularly for EU Stage V and IMO Tier III for specific DZD and BeHydro configurations, evolve as ABC gains additional approvals; the most current certification status should be confirmed with ABC directly for any project application.

See also

• Anglo Belgian Corporation (ABC) marine engines: full corporate history, the complete engine catalog from DX through DL36, market strategy, and manufacturing
• Medium-speed four-stroke marine engines: engine class overview covering trunk-piston design, bmep, rating conventions, and major makers
• Trunk-piston engine architecture: the mechanical layout shared by every DZC variant
• SEMT-Pielstick marine diesel engines: the 1973 PA4 licence that shaped the DZC’s development
• Hydrogen as a marine fuel: production pathways, bunkering, safety, and GHG accounting for marine hydrogen
• Methanol as a marine fuel: fuel properties, bunkering infrastructure, and safety
• Selective catalytic reduction: the NOx after-treatment system used on DZC Tier III and BeHydro installations
• Emission control areas: where IMO Tier III applies and the NOx limits that drive SCR adoption
• Tug operations and bollard pull: how DZC-powered tugs are rated and compared
• Marine auxiliary engines and generators: DZC in genset duty on larger vessels
• Pilot injection in dual-fuel engines: the diesel pilot that ignites gas or methanol in DZD dual-fuel operation
• MARPOL Annex VI Reg.13 NOx: the IMO Tier I/II/III framework the DZC is certified against

Related calculators

• Brake Mean Effective Pressure (BMEP) Calculator
• Mean Piston Speed Calculator
• Marine Engine Model Decoder
• Engine Thermal Efficiency from SFOC
• Inland Waterway Vessel Fuel and CO2 Calculator
• System: Auxiliary Engine Medium-speed 4-stroke
• Auxiliary Engine Load Factor