Yanmar diesel engines are compact, water-cooled industrial power units manufactured by Yanmar Co., Ltd., Osaka, Japan. They are widely fitted as original equipment in mini excavators, compact wheel loaders, skid steer loaders and small generator sets, primarily within the 1- to 8-tonne operating weight class.
Design and Power Range
The core product line for construction machinery is the TNV series, offered as 2-, 3- and 4-cylinder configurations (e.g. 2TNV70, 3TNV76, 3TNV88, 4TNV98, 4TNV107). Displacement ranges from approximately 0.5 L to 4.0 L. Rated power output for machinery applications typically spans 10 kW to 75 kW, covering the power bands most relevant to mini and compact excavators. Engines use direct injection and, depending on model and emission tier, mechanical or common-rail fuel systems with turbocharging on higher-output variants.
Emission Standards
Current production engines sold into the EU and UK comply with EU Stage V / UK Stage V under Regulation (EU) 2016/1628. The regulation defines power categories with different exhaust aftertreatment requirements. Engines in the 8 kW to below 19 kW category (NRE-c-2) are subject to a particulate mass (PM) limit but no particulate number (PN) limit, so compliance is generally achieved without a diesel particulate filter (DPF), using cooled EGR and a diesel oxidation catalyst (DOC). From 19 kW upward (NRE-c-3 and higher categories), a PN limit of 1.0 x 10^12 #/kWh applies, which in practice requires a DPF in combination with DOC and, on larger displacement models, SCR for NOx reduction. In the US market, equivalent Yanmar engines are certified to EPA Tier 4 Final requirements, which follow a comparable power-based structure for aftertreatment.
Typical Applications
Yanmar engines are supplied as OEM power units to multiple excavator and compact equipment manufacturers in addition to Yanmar's own construction equipment brand. Common installations include mini excavators from 1.0 t to 8.0 t operating weight, compact track loaders, mini wheel loaders and compact utility tractors. Mounting dimensions, PTO configuration and cooling package are adapted per machine model by the equipment manufacturer.
Maintenance Intervals
Standard service intervals for TNV-series engines include engine oil and filter change at 250 operating hours, fuel filter replacement at 500 operating hours, and air filter inspection at 250-hour intervals with replacement as needed. DPF-equipped models require periodic ash cleaning, typically every 3,000 to 4,500 operating hours depending on duty cycle, performed by removal and off-machine cleaning or exchange of the filter element.