Kohler’s new K-HEM 2504 hybrid engine combines diesel and electric in parallel

First published at CONEXPO-CON/AGG - March 12, 2020

Kohler’s K-HEM 2504 uses diesel and electric engines in parallel

Kohler has launched two new hybrid engines which combine diesel and electric power in parallel: the K-HEM 2504 and the K-Hem 1003. The idea behind the combination is to provide the bulk of the power from the diesel engine, with the electric motor kicking in when peaks are required.

“That allows for a smaller engine to be used where currently a larger one is needed,” explains Jeffrey Wilke, product manager for Kohler Engines. “That means that in some applications there will be savings in fuel and reduced noise.”

Kohler has chosen the size of the diesel engines in the two hybrids to fall just below two thresholds. The K-HEM 1003 sits just below 19kW, the limit required for Diesel Particulate Filter (DPF) under Stage V Legislation. The K-HEM 2504 sits below the limit at which Stage V legislation requires Selective Catalytic Reduction (SCR).

The K-HEM 2504 combines a KDI 2504TCR 55.4 kW diesel engine that complies with Stage V legislation and is without SCR, and a 48 Volt electric motor that guarantees 19.5 kW peak power and 9 kW continued power and doesn’t exceed safe voltage levels. The electric motor charges from the diesel one when not in use.

“The hybrid takes a 74hp engine and gives it almost 100hp,” says Wilke. “You can also have instant torque from the electric engine because you don’t have the diesel curve.”

Kohler is currently talking to a range of OEMs about how the engines could be used. The challenge will be to programme the ECU controls to best match the use of the engines to the duty cycle of the machine. There will also be an additional cost, compared to a diesel-only engine, due to the battery for the electric one, so OEMs will have to find the right applications to exploit the new technology.

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