According to Kohler Engines, its new KDI 3404 model completes its platform of KDI diesel engines, which now range across three models from 30 to 100 kW (40 to 134 hp). The 3404 reaches 100 kW (134 hp) at 2200 rpm and 500 N·m (364 lb·ft) at 1400 rpm. It also reaches 412 N·m (304 lb·ft) at just 1000 rpm, enabling demanding work cycles at low rotation speeds, and reducing fuel consumption by up to 10% while significantly limiting noise levels.

The turbocharger, engine, and electronic control unit were designed together to offer an immediate response to variations in load, enabling 15% higher levels of machine productivity compared to leading competitors, claims the company. The KDI 3404 also offers efficiency in terms of the cost of ownership, with maintenance intervals of 500 hours without the need for a diesel particulate filter (DPF).

All of the models meet current emissions standards without the use of a DPF, which was made possible by the 2000-bar (29-ksi) high-pressure common rail injection system offering clean combustion, helped at least in part by G3S solenoid-type injectors that offer precise supply of fuel during the injection process and the use of an electronically controlled EGR valve for the recirculation of the precise amount of exhaust gas. The range of KDI 3404 engines is completed by mechanical versions that are suitable for less regulated markets.

The KDI 3404 was developed by Kohler, with some help from Ricardo, to operate at performance levels usually seen with higher displacement engines, with a power density of 30 kW/L. As a result, OEMs can replace higher displacement engines with versions that have a considerably smaller footprint to reduce consumption without necessarily redesigning their application or, in the case of new machines, designing smaller engine housings leading to improved operator visibility and productivity.

The lack of a DPF helps to increase productivity for the end user, who no longer has to slow down the work cycle because of the regeneration process, and make installation easier as there is no longer any need to adopt expensive safety measures to counter excessive heat loss and prevent fire hazards.

The two lateral auxiliary PTOs (SAE A and SAE B) were engineered to deliver maximum engine power and simplify integration with the hydraulic system of the various applications, reducing the space taken up by the machines. The bedplate architecture (crankcase and sub-crankcase) used for the engine block and its counter-rotating crankshafts also contribute to reduced levels of vibration and noise.

The design of the KDI 3404 makes it the slimmest engine in its class, says the company, particularly important for agricultural applications where engines are placed on the front axle and have to be compact size with less width to give farming vehicles a better turning radius, thus making maneuvering easier.

In configurations above 56 kW (75 hp), the KDI 3404 engine complies with Stage IV/Tier 4 Final exhaust gas standards via the use of selective catalyst reduction (SCR) to reduce NOx in the exhaust. The “all-in-one” SCR system contains the DOC (diesel oxidation catalyst), the mixing pipe, and the SCR in a single piece of equipment. The compact footprint of the whole device and the possibility to fit it at any angle simplifies its integration with the machine.

The KDI 3404 is also essentially Stage V ready, with the SCR system having been designed so it can accommodate a DPF, currently the only technical solution capable of meeting the requisites for the number of particles of particulate in the proposed law in the process of assessment by the European Commission and expected for 2019.

In the case of the 3404, it was engineered and designed such that the current all-in-one SCR module will simply have to be replaced with a new module that will be exactly the same size. The DPF used will be small and its use will benefit the already clean combustion, consequently having a lower number of regenerations than any other DPF while maintaining high levels of productivity.