Off-highway diesels — agricultural tractors, construction machinery, gensets, marine engines, locomotives, mining trucks — use a wider range of Bosch fuel-injection hardware than pickups do, because the equipment in the field spans fifty years of technology. Here's a map of the major Bosch systems you'll encounter, from mechanical pumps still working every day to modern common rail.

The mechanical era — still very much in service

• Inline pumps (P-series and similar): one pumping element per cylinder, engine-oil lubricated, used on 2–12 cylinder engines at pressures up to 1,800 bar. Common on older ag, construction, marine, and stationary engines.
• PF single-cylinder pumps: individual cam-driven pumps for small tractors, generators, and compact construction machinery — and, in large formats, for big marine and stationary engines.
• VE and VP distributor pumps: one pumping unit distributing to all cylinders. Indirect-injection versions run modest pressures; later direct-injection versions reach up to 1,950 bar.
• Nozzle-and-holder assemblies: the matching injector hardware for these mechanical systems, rated up to 1,800 bar.

These systems are mechanically governed (later versions electronically), and parts remain in steady demand precisely because the equipment refuses to die.

Modern common rail for off-highway: CRSN

Bosch's CRSN is the modular common-rail system for commercial and off-highway engines from roughly 4 to 17 liters and up to 850 kW. It runs 1,800–2,500 bar and combines the CRIN solenoid injector (fast-switching, leakless, multiple injections per cycle), the CPN6 high-pressure pump, and a hot-forged rail. Rail-pressure control and multiple injection events are what let current Tier 4/Stage V equipment meet emissions without sacrificing fuel economy.

Large engines: MCRS

Above roughly 560 kW — think marine propulsion, locomotives, mining haul trucks, and big gensets — Bosch's Modular Common-Rail System (MCRS) takes over. It scales to 24 cylinders and 5,000 kW, running 1,600–2,200 bar, with the CRIN-LE injector (up to 450 kW per cylinder, with an integrated fuel accumulator) and the oil-lubricated CP9 inline high-pressure pump. Unit pumps and unit injectors also serve this class on some platforms.

What this means when you're buying parts

Off-highway parts lookups live and die by the part number. The same engine family can carry different injection systems by year, market, and emissions tier — so identify the system first (data plate, existing pump/injector part number), then cross-reference. A number stamped on the old unit beats any assumption about what "should" be on the engine.

Before you order: verify the exact pump or injector by OEM cross-reference for your engine — off-highway applications especially.

We stock injectors and pumps for on- and off-highway diesels: see our fuel injector catalog and fuel pump collection, or send us your part number via the chat box and we'll confirm fit.