Development of an Engine-in-the-loop Vehicle Simulation System in Engine Dynamometer Test Cell

Abstract

To meet the ever increasing requirements for engines and vehicles in the areas of performance, fuel economy, emission, and meanwhile reduce product development time,Hardware-in-the-loop (HIL) simulation is increasingly used in automotive control system development.Engine-in-the-loop (EIL) vehicle simulation, which is a specific form of HIL simulation, is an approach in which a physical engine (together with its control unit) is coupled to virtual vehicle and driver models through a high power, low inertia engine dynamometer in the engine test cell environment. EIL can be used to perform powertrain control development, as well as engine and vehicle performance evaluation. Because of its advantages in repeatability and flexibility etc., especially for transient operating mode study, EIL has become a powerful tool and will be more widely used in the near future.Design and implementation of an EIL vehicle simulation system is described. Driver and vehicle simulation models are developed and executed in real time on a high-speed system controller. A highly responsive permanent magnet AC engine dynamometer and a vehicle acceleration pedal are controlled such that the dynamometer loads the connected engine as a real vehicle would and the simulated vehicle speed trace follows the targeted driving cycle. With this system, developers can perform transient engine control development before whole vehicle integration is available. Vehicle parameters, including driveline configurations can be easily modified and the effect on engine and vehicle performance can be studied. An application example of simulating a 10-15 mode emission test cycle is given. The result verifies the effective performance of the system in simulating vehicle dynamics and shows its great potential in engine and vehicle system development.

A novel road dynamic simulation approach for vehicle driveline experiments

“…Z.Hakan Akpolat [10] added a feed forward compensator G comp (s) to the control block diagram of Figure 3…”

On emulating engine and vehicle transient loads for transmission-in-the-loop experiments

“…The drive then controls the motor to produce the desired speed/torque values. The speed and torque response of the transmission to these setpoints are sensed at the dynamometer shafts using an encoder and torque meter respectively, and communicated to Procyon as PWM signals [6]. The transmission controller is also physically present in the system, and communicates with the emulated engine controller on Procyon through CAN messaging.…”

“…Since the objective here is to subject the transmission input to torque pulse, the engine model commands the torque setpoints to the drive, and the speed of the input dynamometer shaft is measured and communicated to the engine model as the engine speed. The torque setpoint received by the drive is achieved using a closed-loop PID controller residing on Procyon [6]. The drive contains motor's open-loop torque estimators, and varies the duty-cycle and switching frequency of the voltage to achieve the current required to produce the desired torque [7].…”

Engine torque pulse and wheel slip emulation for transmission-in-the-loop experiments

“…The drive then controls the motor to produce the desired speed/torque values. The speed and torque response of the transmission to these setpoints are sensed at the dynamometer shafts using an encoder and torque meter respectively, and communicated to Procyon as PWM signals [5]. The transmission controller is also physically present in the system, and communicates with the emulated engine controller on Procyon through CAN messaging.…”

“…Since the objective here is to subject the transmission input to torque pulse, the engine model commands the torque setpoints to the drive, and the speed of the input dynamometer shaft is measured and communicated to the engine model as the engine speed. The torque setpoint received by the drive is achieved using a closed-loop PID controller residing on Procyon [5]. The drive contains motor's open-loop torque estimators, and varies the duty-cycle and switching frequency of the voltage to achieve the current required to produce the desired torque [6], [7].…”