Clutched super turbo control strategy

Abstract

A method of controlling an internal combustion engine boosting system of the type including an exhaust-driven turbocharger (33) and a mechanically-driven supercharger (15). The supercharger (15) includes rotors (21) and a clutch (27) operable in a first condition to transmit torque from a mechanical drive source (E) to a supercharger input (25) in response to a positive input (75), and operable in a second condition to interrupt the transmission of torque from the source (E) to the input (25). The method is characterized by determining possible operation of the clutch (27) in a first condition; and commanding a bypass valve (53) toward a closed position, forcing air through the supercharger (15). The airflow causes the supercharger rotors (21) to rotate, thus rotating the input (25) of the supercharger prior to the clutch (27) operating in the first condition.

Description

Technical field [0001] The present invention relates to a vehicle engine supercharging system, and more particularly to such a system including a mechanically driven supercharger (such as a Roots type blower) and an exhaust-driven turbocharger type. This type of vehicle engine supercharging system is sometimes abbreviated by the term "supercharged turbo". Background technique [0002] As known to those skilled in the field of vehicle engine supercharging, there are two main types of supercharging devices that are generally used to increase the air pressure in the combustion chamber of an internal combustion engine. The first type is generally referred to as a "supercharger" (although the term is sometimes used generally for all superchargers). For the purposes of this specification, the term "supercharger" will be understood to mean and include mechanical The driven supercharging (air pumping) device, that is, the supercharger is driven at a speed that is usually proportional to ...

AI Technical Summary

Problems solved by technology

Secondly, it has been observed that due to sudden and large changes in the speed of the supercharger (high angular acceleration) when the supercharger clutch is engaged, especially at the lower end of the load range and speed range in which the supercharger can operate On the higher end of the , the engagement of the supercharger can be uncomfortably jerky

In addition, when the supercharger clutch is disengaged (for example, at engine speeds above about 3,500 rpm or below 3,500 rpm when the demand load is low enough to be satisfied by the turbocharger alone), and then the engine speed The re-engagement of the supercharger clutch (for example, the input of the supercharger is fixed and the clutch speed is 2500rpm) usually occurs in a sudden manner when the supercharger needs to be operated again after that, which is likely to cause the durability of the clutch to decrease. decrease over time and cause undesired NVH conditions

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