Dynamic cylinder shut-off opens up efficiency potential for gasoline engines
Due to the importance of this unique and unique approach by DSF to reduce fuel consumption and CO2 emissions, the Tula and Delphi engineers present with a demo vehicle how to achieve these savings potential without compromising the engine’s running even in supercharged four-cylinder engines. What’s more, the technology does not add a heavy surcharge to the price of the motor: engines equipped with the DSF technology cost only 40€ more per saved percent of fuel than non-DSF engines, the developers claim.
DSF calculates cylinder-selectively before each individual ignition process, whether or not the cylinder is ignited. DSF uses a number of parameters to determine which cylinder to ignite next: the driver’s demand for load, the current NVH behavior (noise, vibration, harshness) of the engine, and the noise frequencies and amplitudes that potentially can affect the comfort in the vehicle.
The ignition sequence is continually adapted to the vehicle dynamics, so the engine always operates at optimum performance, as this reduces pumping losses and at the same time improves its thermal efficiency. The unique control strategy also allows new combustion concepts and thus the development of further efficiency potentials. For example, the cylinder-selective control can provide for instantaneous torque equilibrations, in particular in partial-load operation. Another advantage of DSF is the deactivation of all cylinders in the sliding mode, which firstly minimizes the pump losses and allows a longer coasting, and secondly reduces the risk of unburnt fuel entering the catalyst causing damage there.
At the Vienna Motor Symposium, Delphi and Tula presented the DSF technology in a demo vehicle with a four-cylinder gasoline engine, 1.8 l displacement and turbocharging. Driving tests with the demonstrator showed that the engine running characteristics of the DSF demo vehicle are comparable to that of a standard vehicle in the entire frequency range. However, the fuel consumption of the DSF prototype motor was reduced by up to 10% in standard measurement cycles (such as NEFZ, WLTC, US Combined, JC08). Engineering teams from both companies are currently working on another demonstrator that combines the advantages of DSF with those of a mild hybrid drive. When this combinatorial concept is fully implemented, the developers expect fuel savings of up to 20%.
Serial production of a V8 engine with DSF is already planned, while Delphi and Tula are driving a four-cylinder application of DSF together with an unnamed car manufacturer.