Kohler’s Big Move In Small Engines

Kohler has unveiled a new range of small diesel engines for mobile and stationary applications. The Kohler Small Displacement (KSD) engines will be available globally in naturally aspirated, turbocharged and turbocharged charge-air cooled versions.

Kohler is making a big move in the global market for small engines.

Aiming to provide flexibility for both mobile and stationary applications, the company has unveiled a new range of compact diesel engines that will be offered in naturally aspirated, turbocharged and turbocharged charge-air cooled versions to meet exhaust emissions regulations in the U.S. and EU, as well as new emissions norms in India (Bharat Stage 5 in 2024), China (Stage 4/Stage 5), Japan and Korea

The Kohler Small Displacement (KSD) engines are three-cylinder engines with bore and stroke dimensions of 81 x 90 mm and an overall displacement of 1.391 L. The naturally aspirated models will offer ratings of 18.4 kW (24.6 hp) at 2200 rpm, with maximum torque of 90 Nm (66 lb. ft.) at 1800 rpm.

The turbocharged engines will have the same maximum horsepower, with torque rising to 105 Nm (77 lb. ft.) at 1500 rpm while the turbocharged and charge-air cooled engines will see torque top out at 120 Nm (88.5 lb. ft.) at 1400 rpm.

The KSD will also be available at launch with EU Stage 5 and EPA Tier 4 final generator set ratings. For the 50 Hz markets, standby power ratings will be 13 kW (17.4 hp), 16.5 kW (22.1 hp) and 18.8 kW (25.2 hp), while prime power ratings are 11.7 kW, 14.9 kW and 17.1 kW. All 50 Hz ratings are at 1500 rpm.

For the 60 Hz markets, standby ratings are 17kW and 18.4 kW, while prime ratings are 16.2 kW, 16.7 kW and 18.4 kW, all at 1800 rpm.

Clean sheet design

The new KSD engines are intended to eventually succeed the existing Kohler KDW series engines. The KSD engines are a completely new design that was heavily influenced by Kohler’s OEM customers. “With this engine, we had a lot of early conversations and we partnered with some of our OEMs and got input from them even before the design,” said Jeff Wilke, Industry Channel Manager – Engines at Kohler. “It’s a clean sheet design like the KDI engines and our targets were best-in-class performance, total cost of ownership – we know that’s a focus for our customers these days – heavy-duty design and unique technical solutions.

“The people who have given us input have seen the result of that input in this engine.”

The naturally aspirated KSD engines will offer ratings of 18.4 kW (24.6 hp) at 2200 rpm, with maximum torque of 90 Nm (66 lb. ft.) at 1800 rpm.

The KSD engines incorporate an electronically controlled indirect injection (IDI) system in which fuel is delivered into a pre-chamber where it is mixed with air and ignited before passing into the combustion chamber where the combustion cycle is completed. The system uses low pressure (250 bar/3600 psi) fuel injectors based on gasoline direct injection (GDI) technology.

The fuel system is designed to provide precise fuel metering and strong load response, along with good performance at altitude. The control electronics also allow for prognostics, diagnostics, and remote monitoring, as well as integration with other machine systems through CAN J1939 communications networks

Compact dimensions

Kohler said the KSD engine is designed to fit in the same application envelope where 1.1 L engines are currently used - thus providing a drop-in replacement to competitive engines - while still delivering the horsepower and torque performance of a 1.7 L engine.

“It’s almost 1.4 L, however, it’s in the package size of a 1.1 L engine,” said Wilke. “It’s very compact,” with length, width and height dimensions of 505 x 409 x 605 mm (19.88 x 16.1 x 23.8 in.) for the naturally aspirated engines and 505 x 450 x 652 (19.88 x 17.7 x 25.6 in.) for the turbocharged engines. The weight ranges from 95 kg (209.4 lb.) for the naturally aspirated engines and 106 kg (233.7 lb.) for the turbocharged models.

“When you look at this market now at 19 kW and you look at the engine displacements, they range from 900 cc to 1.7 L that have all been pushed all into this same area,” Wilke said. “So our idea is we went more in the middle with 1.4 L, while providing all kinds of torque and performance.

“When you look at most engines in this range, they’ve got to be pretty large displacement before they can even get close to 120 Nm torque. In most cases, you’re looking at close to a 1.7 L engine to be able to do that.”

Even with its compact dimensions, Wilke said the KSD “is a heavy-duty design.”

“Our KDW engine wasn’t perceives as a heavy-duty engine because it has an overhead cam that was belt-driven,” Wilke said. “People just saw that it had a belt and that’s just not seen as heavy-duty.

“This engine goes back to the in-block cam design that is very robust. It also has large bearings to handle the higher loads of applications where larger displacement engine were used and now can be replaced with the KSD due to the robust design.”

Drop-in features

The drop-in capability of the KSD engines is also enabled by features such as:

- A fully adjustable cooling fan mount, allowing three different fan positions and eliminating any radiator repositioning in the application.

- A dual side service capability, allowing the oil filter, dipstick and fuel filter to be located on either side of the engine.

- A third power-takeoff (PTO), available, as well as a non-PTO option.

- Standard 500-hour oil change interval with 1000-hours available for select applications.

Kohler plans to begin production of the KSD engines at its Aurangabad, India, facility in October of 2022. “We are building a new portion of our Aurangabad plant,” said Nino De Giglio, director, Marketing Communication and Channel Management for Kohler in Italy. “And it’s not just building a new building, the processes of the assembly line will be very innovative.”

The company also has plans to develop spark-ignited versions of the KSD engine that will be capable of operating on gasoline, natural gas and LPG. Those engines, currently expected to launch in the 2025 timeframe, will also be available in naturally aspirated (23.2 to 27.6 kW/31 to 37 hp) and turbocharged (35 to 37 kW/47 to 49.6 hp) models.

More information on the new KSD engines will be included in an upcoming issue of Diesel Progress.

www.kohlerengines.com