Theoretical calculations of the relative additional fuel consumed when shutting down the cylinder

Abstract

Cylinder deactivation is a technique used to improve the efficiency of an engine by shutting down a certain number of engine cylinders. Cylinder deactivation allows the remaining cylinders to operate more efficiently, increasing their load and improving efficiency. This technique has gained interest both domestically and internationally, particularly for automotive engines, as it helps improve fuel economy at idle and light loads. The process of calculating effective cylinder deactivation in a multi-cylinder engine and its effect on additional fuel consumption is discussed. The need to improve engine efficiency in various speed and load modes is driven by requirements for fuel economy, reduced exhaust toxicity, and the need to improve engine transients while maintaining other characteristics. In order to effectively utilize engine power and maintain performance, the fuel supply to operating cylinders must be increased. However, deactivating cylinders during engine operation results in a decrease in engine power, which in turn reduces crankshaft speed and torque. In summary, cylinder deactivation is a technique that has the potential to improve the economic performance of engines, particularly at idle and light loads. A method for effectively deactivating cylinders in multi-cylinder engines has been developed based on the dependence of indicator efficiency on load changes. The study examined the effect of cylinder deactivation on mechanical losses and efficiency when load is reduced from 100% to 30%. The results showed that it is possible to use only two cylinders of a four-cylinder engine at 30% load, resulting in reduced mechanical losses and improved efficiency. A proposed method for determining the relative additional fuel consumption when cylinders are deactivated is presented. Deactivated cylinders do not supply air to the exhaust manifold, which reduces pumping losses and creates less rolling resistance, resulting in up to a 25% reduction in fuel consumption. This reduction is especially noticeable in urban driving.