Characteristics and Realization of Variable Displacement

Characteristics and Realization of Variable Displacement

(1) Features of variable displacement:

Variable displacement can be understood as an on-demand cylinder management system. As the name implies, it is a system that relies on the judgment of the vehicle's power demand (engine load) to adjust the engine's working conditions accordingly. For example, the Audi 4.0TFSI twin-turbocharged engine, when the engine load is low, the system will close the 4 cylinders of the engine, so that the engine will only work with 4 cylinders. This is actually the familiar "variable displacement" Control system", in different manufacturers, it has many different names, such as VCM, MDS, AFM, etc., in the products of Mercedes-Benz, Honda, General Motors, Chrysler and other brands, there are such products that save energy by closing the cylinder. Consumed technology.

(2) Implementation method of variable displacement:

In terms of means of realization, it is also similar to other manufacturers’ methods. It relies on an upgraded version of Audi’s variable valve lift control system (AVS) and adds a set of “zero lift” cams to its camshaft. . When switching to this set of "zero-lift" cams, the camshaft will not be able to drive the valve movement, and the intake and exhaust valves of the 2, 3, 5, and 8 cylinders will be closed.

◆ To achieve closed cylinder operation, the working conditions of the engine need to meet the following conditions: first, the engine speed is higher than the idle speed, between 960 and 3500r/min, and the engine output torque is between 25% and 40% of the peak torque; The second is that the temperature of the coolant should be higher than 30°C, and the gear of the gearbox should be above the third gear. The "sport mode" of the gearbox does not affect the work of the system.