Ducati DVT Engine Introduces Desmodromic Variable Timing

Ducati DVT Engine

Ducati has taken the crate off its new 1198cc engine that features Desmodromic Variable Timing (DVT).

The unveiling occurred just ahead of Milan’s EICMA motorcycle show in Milan, where the Borgo Panigale manufacturer is expected to debut the new Multistrada

Why is this important? The Multistrada, which currently uses the 11-degree 1198cc Testastretta L-Twin, is the most likely candidate for the new engine.

Variable timing is nothing new to the motorcycle industry  (think Honda VFR VTEC engines). But the Ducati DVT is the first engine to feature variable timing of both the intake and exhaust camshafts (Honda VTEC used variable valve timing). Ducati says the DVT’s variable timing system continuously adjusts valve timing by acting independently on both the intake and exhaust camshafts.

The benefits? More power, smoother power delivery, more torque at lower rpms, reduced fuel consumption, and reduced emissions.

Ducati says the DVT engine, which has received full Euro 4 compliance, retains the same bore and stroke (106mm x 67.9mm) of the engine used in the current Multistrada, along with the Dual Spark (DS) ignition.

But the new variable-timing engine produces a peak of 160 horsepower and 100.3 ft/lbs of torque – 10 more horsepower and nearly 10 extra ft/lbs of torque over the current Multistrada’s 1198cc power plant.

Peak power of the DVT arrives at 9500 rpm – 250 higher than the current Multistrada’s 1198cc engine – but torque delivery is high throughout the rpm range. Ducati says the DVT produces 59 ft/lbs of torque at 3500 rpm, and remains consistent with over 73 ft/lbs between 5750-9500 rpm.

Though more powerful, the DVT uses less fuel. Ducati says the DVT has an 8-percent reduction (average) in fuel consumption compared to the previous non-variable timing configuration.

Ducati achieves this more-optimal fuel consumption through a combination of the DS ignition and repositioned fuel injectors. Ducati says it designers repositioned the fuel injectors to “target their spray directly onto the rear of the hot intake valve, instead of the colder surface of the intake port wall. The resulting enhanced fuel vaporization improves combustion efficiency and ensures a smoother delivery.”

As for Ducati’s Dual Spark (DS) system, it utilizes two spark plugs per cylinder. This provides a “twin flame-front that ensures complete combustion across a very short period of time.”

Elaborating further, Ducati says “each spark plug is managed independently, to optimize efficiency throughout the rev range and in all conditions of use. An anti-knock sensor ensures safe engine operation even while using lower octane fuel or in situations potentially detrimental to combustion efficiency, e.g. at high altitude.”

To offer smoother power delivery, Ducati incorporates a secondary air system on the DVT engine. This optimizes combustion without increasing emissions by completing the oxidization of unburned hydrocarbons to reduce HC and CO levels.

Besides all these advantages, another benefit arrives in valve-clearance checks. The DVT engine requires valve checks at nearly 19,000 miles compared to 15,000 of the previous engine configuration.

When all is combined, Ducati says the DVT can be used in a “wide variety of conditions and locations, while always delivering top performance and exceptional user- friendliness, safety and sheer excitement.”

Sounds like the perfect engine for the next-generation Multistrada, right? We’ll have to wait for EICMA to see if we’re correct.

Following are the highlights of the DVT, and how Ducati officially explains the design of the new DVT.

Ducati Testastretta DVT Engine Highlights:

• Brand-new DVT (Desmodromic Variable Timing) system
• Bore: 106 mm, stroke 67.9 mm
• Capacity: 1198 cc
• Max power: 160 HP at 9,500 rpm
• Max torque: 100.3 ft/lbs of torque at 7,500 rpm
• Desmodromic distribution
• Dual Spark (DS) ignition
• Anti-knock sensor
• Euro 4 compliant

A New Generation of Testastretta Engines

When a new engine is designed, one of the most critical parameters to determine its “character” is the amount of intake and exhaust valve overlap. The overlap angle is defined as the interval of crankshaft rotation, expressed in degrees, during which both the intake and exhaust valves are open at the same time.

This overlap occurs between the end of the exhaust stroke and the start of the intake stroke and is normally a single value that does not change. However, the Testastretta DVT is not limited by a fixed valve overlap angle.

Instead, the Ducati Testastretta DVT’s overlap angles can change, thanks to the introduction of the DVT (Desmodromic Variable Timing) system: a valve timing adjuster fitted to the end of each of the two camshafts per cylinder head.

The DVT system consists of an external housing, rigidly connected to the cam belt pulley, and an internal mechanism which is connected to the camshaft and can independently rotate inside the housing.

This rotation of the internal mechanism, either in advance or in delay with respect to the housing, is precisely controlled by varying the oil pressure in special chambers of the mechanism. The oil pressure is adjusted by dedicated valves and the timing of each cam is dynamically controlled by a sensor located in the cam covers.

The Ducati Testastretta DVT engine uses the unique valvetrain that made the Bologna-based Italian manufacturer a world-famous name. Thanks to this unique system, the intake and exhaust valves are closed mechanically and with the same level of accuracy as they are opened.

The term Desmodromic derives from the Greek words “desmos=link” and “dromos=stroke, travel”; in mechanical engineering terms, it refers to mechanisms designed to actuate valves both in the opening direction and in the closing direction.

This system, used in all Ducati models, has also been extremely successful in Ducati Corse World Superbike and Desmosedici MotoGP motorcycles.

In the development of the DVT, the Desmodromic valvetrain represents a major advantage over a traditional spring based timing system; the actuation of the valves at low engine speed requires less force, not having to compress the valve springs, this allowed Ducati to limit the size of each cam phaser with obvious benefits in terms of lightweight construction and compactness for a perfect engine integration.