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FEV and Neander Motors AG showcasing double-crankshaft turbo-diesel outboard marine engine at SAE World Congress

FEV North America, Inc. a leading developer of advanced powertrain and vehicle system technologies, will showcase a turbo-diesel outboard marine engine developed in cooperation with Neander Motors AG at the upcoming SAE World Congress 8-10 April at COBO Center in Detroit.

Neander, based in Kiel, Germany, is a developer of high performance diesel engines and air compressors for a range of projected applications. The central aspect of Neander technology is a counter-rotating double crankshaft; the pistons act on the two opposing crankshafts via two connecting rods. The double crankshaft offers a number of benefits, according to Neander, including:

Neander diesel with double crankshaft. Click to enlarge.
  • Compensation of all rotating inertial forces;

  • Compensation of all 1st order oscillating forces (torque compensation);

  • No reactive effect due to torque impulses on the exterior of the engine are detectable;

  • No torque due to inertial effect and its phase difference from compensation measures;

  • Very low friction losses from the guidance of the piston by the connecting rod (the lateral guiding force of the piston is effected by the connection rod); and

  • The use of large single swept volumes with better thermodynamic efficiency.

The key enabler for a dual crankshaft engine with a constrained piston movement by two con-rods with theoretically no piston side forces is provision for forgiveness towards tolerances, which can lead to off-design positions of the piston in its cylinder bore and unfavorable mechanical effects such as scuffing, sticking or simply higher friction as the least bad of effects.

Space ball design. Click to enlarge.

To address this issue, Neander invented a “space ball” design, giving the piston the additional degree of freedom of rotational adjustment around the two piston pins. I.e., each piston pin is designed as a “space ball” connected to a pair of side-by-side connecting rods that drive a pair of offset counter-rotating crankshafts. This distinctive layout results in an efficient, light, compact and powerful engine with exemplary smoothness and refinement.

The potential power range of this engine concept ranges from a 400 ccm single cylinder up to to a 1.4 liter two-cylinder engine with a power range from 12 hp to 110 hp (9 to 82 kW) and a torque from 25 N·m to 220 N·m (18 to 162 lb-ft).

Neander says that its diesels will offer an approximate 10% reduction in fuel consumption compared with multiple cylinder diesel engines. Neander has already applied its engine in a motorcycle, and is now trialing the outboard.

Conventional single-crankshaft outboard (top), compared to twin crankshaft Neander (bottom). The elimination of diesel-like vibration from the Neander is one of its keys to the outboard application. Click to enlarge.

The two-cylinder 800cc Neander diesel outboard features a chain-driven camshaft, hydraulic chain tensioner, common-rail direct fuel injection and “square” 80 mm bore and stroke.

The inline two-cylinder turbo-diesel has a maximum rated speed of 4,500 rpm and produces 55 hp/45 kW. Maximum torque is 120 N·m (88.5 lb-ft), generated at 2,000 rpm. In its most basic form, the Neander Motors outboard weighs 155 kg (342 lbs), stands 1241 mm (48.9 inches) tall, and is available in both 20-in and 25-in shaft versions.

As a new participant in the marine engine market, Neander Motors leveraged FEV’s capabilities and collaborated in the development of a small outboard engine for the highly-competitive 40 to 70 hp (30 to 52 kW) commercial market, which is dominated by transport, hauling and commercial fishing. A global development and manufacturing team was organized that focused its efforts over a two year period on creating this engine. FEV provided CAE and testing support for this innovative program.

Outboard marine engines today are almost exclusively gasoline and have many advantages, including small size, low weight and cost, and ease of installation and servicing. Neander’s approach is an evolutionary development, creating a new outboard diesel in the relatively high volume 40 to 70 hp market, offers a high torque-to-weight ratio, low specific fuel consumption and the potential tax advantages with diesel fuel.

—Prof. Stefan Pischinger, CEO of FEV GmbH


Liviu Giurca

A more advanced solution with a single crankshaft and opposite pistons is described in . This has also very law friction of the pistons with a cylinder walls and the missing of the side force but is simpler (no cylinder head and a single crankshaft). On the other hand this concept offers the exceptional benefits of the opposed piston engines: reduced heat losses and extended expansion stroke without to increase the overall size of the engine.


But an opposed piston engine is too bulky to be practical in outboard applications.


On and off between about 1990 and 2001, I worked on a 2-stroke opposed piston diesel engine that had the same crank, piston and connecting rod layout except that it now had 1 cylinder, 2 pistons, 4 connecting rods, 4 cranks, and a whole gear train to couple all the cranks together. I was not the designer but made an animated solid model of the assembly along with actual 1/3 scale rotating model of the first design which had a 1.5 liter displacement. The designer was Marius Paul from Engine Corporation of America (ECA). Unfortunately, their web site is no longer active. Later I was involved in making the cranks, connecting rods, and gears for a 3 liter per cylinder version. The engine was designed to run with an extremely high boost of about 150 psi. The 1.5 liter engine ran but had a number of problems with injectors, piston rings, etc. The 3 liter version was never completed.

Anyway, I wonder some about the claim that "Neander invented a “space ball” design" as the engine I worked on had this design. Also, I know that FEV and Southwest Institute (SWI) had access to the ECA engine designs. Some of the original work was done with Detroit Diesel under a DARPA contract. The design does have the advantage that it does not have any piston side loads and it also has an advantage that they did not mention in that the compression take about 160 degrees of rotation while the expansion has about 200 degrees. However, it also has a lot of complexity that the single connecting rod, single crank engine does not have. I thought that the opposed piston opposed cylinder (OPOC) engine from EcoMotors with a single center crank was a clever solution to the multi-crank opposed piston engine with the gear train required to couple the cranks together. Interestingly, FEV was also involved with the OPOC engine.


At 342 lbs, this is truly a Neanderthal engine


Evinrude spark ignited normally aspirated multifuel two stroke 55 hp weighs 250 lbs. The Yamaha spark ignited normally aspirated gas 4 stroke weighs 250 also. 40% more weight for a compression ignited turbo charged with 2 cranks! It will be interesting.


The picture is of the motorcycle engine cut away a DOHC engine of 1.35 litres. The cranks seem to be single sided for both cylinders and it is 360 degree crank ie both pistons rise and fall together, just like the Norton, BSA, Triumph, Royal Enfield twins of old. So the exhaust note, that escapes the turbo, will have the regular beat! This is going to be interesting! The weight of the cruiser is 295 kg.

Roger Pham

Mercury outboard 3-cylinder 800cc gasoline engine 25-30 hp rating weighs around 150 lbs. Double this to equal the 55 hp of the "Neanderthal" engine would make the Mercury outboard 300, "Neanderthal" engine by name, but not "Porky" at all!

This Neander engine would be great for PHEV's needing a compact engine w/ high fuel efficiency in order to limit the size of the fuel tank. The twin crankshaft engine is self-balancing, thus ideal for single or twin-cylinder engine without requiring any additional balance shaft. Thus, the slight increase in complexity will pay for itself in term of self balancing, efficiency gain due to low cylinder count and low friction, and low piston wear due to the lack of side loading of the piston/cylinder.

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