Advantages and disadvantages of Wankel engines
Due to their design, Wankel engines are far lighter, more compact and simpler than classic reciprocating piston drives. There are no reciprocating pistons, cranks, valves, rods or other complex parts prone to failure. Rotary motors contain only three moving parts, making them more reliable, durable and easier to maintain than traditional internal combustion engines. In addition, these moving parts rotate continuously in one direction, ensuring higher operating speeds, simplified balancing and low vibration. Thanks to their unprecedented weight-to-power and size-to-power ratios, Wankel engines are used in a variety of applications, from light aircraft to power generation to boat and ship building, as well as range extenders for electric vehicles.
One of the disadvantages of rotary piston engines is their low thermal efficiency. The long, thin and moving combustion chamber results in relatively slow and incomplete combustion of the fuel-air mixture. This results in higher carbon emissions and lower fuel efficiency compared to gasoline engines. However, this problem becomes an advantage with the switch to hydrogen operation.
Another weakness of Wankel engines relates to rotor and apex sealing. Poor sealing between the edges of the rotor and the housing - for example, due to wear or insufficient centrifugal force in the lower speed ranges - can cause combustion gas to escape into the next chamber.
Since combustion takes place in only one section of the drive, there is a high temperature difference in two separate chambers. The resulting different expansion coefficients of the materials involved lead to a suboptimal rotor seal. Oil consumption is also a problem, as oil must be injected into the chamber to improve lubrication and keep the rotor tight.