Traditional embedded systems employ a time-triggered scheduler or an event-triggered scheduler, however, the truth is that time-triggered scheduling architecture is more dependable but lack of responsiveness to external events and event-triggered scheduling architecture is responsive. In order to get those advantages at the same time, a real-time kernel with a hybrid scheduler, named SinewOS, is developed. In SinewOS time-triggered scheduling and event-triggered scheduling are employed and in order to make this kernel more predictable and high efficient, then cooperative and preemptive scheduling approaches are adopted. The features and the implementation of SinewOS are described in detail. This new kernel has been successfully implemented on LPC2129. And to evaluate the performance of an embedded system employing SinewOS, a testing case is carried out with a simulation, which is a hardware-in-the-loop simulator and based on an adaptive cruise control system (ACCS) platform.