Method for starting an internal combustion engine within a hybrid powertrain

Abstract

The invention relates to a method for starting an internal combustion engine within a hybrid powertrain. The hybrid powertrain includes an internal combustion engine, an electro-mechanical transmission and an electric machine. In an engine starting routine, flow control devices located proximate each combustion chamber in the engine initially restrict airflow into the cylinders to allow for a starter motor to rotate the engine at lower expansion and compression torque whereafter rotation of the engine is transitioned to the electric machine.

Description

technical field [0001] The present invention relates to the starting operation of an internal combustion engine within a hybrid powertrain. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. [0003] The internal combustion engine in a hybrid powertrain requires a quick start when determined by a control algorithm and based on the operating conditions of the vehicle. High low end torque is required to initially turn and accelerate the crankshaft to acceptable speeds prior to combustion. When the intake manifold pressure is high and the mass of air trapped within the cylinder is high, the initial high low-end torque is largely due to cylinder compression torque. One conventional method of starting an internal combustion engine in a hybrid powertrain is accomplished by using an electric machine to accelerate the engine crankshaft to a speed that initiates combu...

AI Technical Summary

Problems solved by technology

However, this approach is complicated in situations where the motor is multitasking (for example, driving the vehicle with most of the total motor torque and starting the engine at the same time)

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