This past January, Hatz Diesel began series production and sales of its brand new four-cylinder 4H50TIC diesel engine. Hatz announced at ConExpo that during the development of the 2-L 4H50TIC, one of its primary objectives was to reduce size and weight while maintaining integrity in performance and exhaust gas values. The result is a compact turbocharged engine that achieves a maximum output of 75 hp (55 kW) and weighs just 381 lb (173 kg). This represents the benchmark in its performance class, with competitive engines weighing in about 180 lb (82 kg) more, according to Hatz.

Besides reducing weight, Hatz engineers were also determined to eliminate the DPF. Fulfilling the EU 97/68 Stage IIIB and EPA Tier IV final limits, the exhaust aftertreatment requires just a robust diesel oxidation catalyst (DOC) that works without any electronics and is maintenance-free. The DPF was able to be eliminated due to the reduction in PM that occurs during the combustion process, but a DPF can be adapted as an option based on regional and local requirements.

The generation change of Hatz engines from purely mechanical to electronically controlled engines reduces the number of variants significantly. While the current engine series needed to be adapted with a variety of options depending on the application, the 4H50TIC does not. For example, the starter protection is now integrated in the control unit. A maintenance free hydraulic automatic valve adjustment system ensures that there is no need to interfere with the fuel system. In addition, a pre-heat system that enables a cold start at -22°C (-7.6°F) is included in the standard engine.

Two auxiliary PTO points are included with the engine in addition to the main PTO that can be loaded with 96 lb·ft (130 N·m) continuously for applications such as hydraulic pumps. The mounting works with an additional housing with a gear ratio that is driven directly by the camshaft.

The water-cooled 4H50TIC features two valves per cylinder to offer mechanical robustness and functional simplicity. As the engine is being manufactured in Germany (where its development also took place) essential parts of the engine such as fuel injection, crankcase, crankshaft, camshaft, EGR valve, catalytic converter, and sensors are sourced mainly from German suppliers.

Along those lines, one of the key factors Hatz attributes to the high power density of the 4H50TIC is the Bosch common rail system that offers 1800 bar (26 ksi) and designed specifically for off-highway industrial engines. This particular common rail works with three injections per working cycle. Opting for a pre-, main-, and post-injection allowed for an optimal balance between durability, quiet combustion noise, and emissions values, says Hatz.

In terms of fuel efficiency, the engine has a specific fuel consumption of 205 g/kWh (best point). Hatz is quick to point out that a unique advantage of the 4H50TIC compared to its competitors is that the low fuel consumption is achieved in a wide load and speed range “unrivalled in this class” of 50 to 76 hp (37 to 57 kW) engines. Pilot applications under real conditions show a fuel saving potential of approximately 30% compared to an EU Stage II engine.

For reduced exhaust emissions, the EGR mixing nozzle was developed to evenly distribute the recirculated exhaust gas together with fresh combustion air to all four cylinders. It is this technology along with the common rail system that led to the demise of a mandatory DPF.

Also contributing to improved fuel efficiency is the reduction of internal friction, which was achieved via a design that incorporated very few moving parts. Among others, the use of a timing belt and timing chain is not necessary as the valve train is driven through a gear, push rods, and rocker arms. In addition, the two-valve technology with roller tappets and a camshaft in block contributes significantly to the reduction of internal friction. High-end materials have been used for connecting rods and bearings.

Application possibilities for the 4H50TIC can be divided into three areas that Hatz identifies as mobile devices, machines, and stationary machines. Mobile machines include mini excavators, wheel loaders, and forklifts; machinery includes aerial platforms, wood chippers, drills, and pavers; and stationary engines comprise pumps and generators.

Due to the compact design, the 4H50TIC can also be integrated into existing applications. Fans and the oxidation catalyst can be installed in different mounting positions and thus provide more flexibility during set up. Also, due to its size, the space requirement is considerably lower than that required of comparable engines.