Search Results

Torque profile control is one of required technologies for propulsion engines. A smaller parametric model is more preferable for control algorithm design and evaluation. Mean value engine torque can be obtained from throttle opening change using a transfer function. A transfer function for a turbocharged engine was investigated with thermo-dynamic equations for a turbine and a compressor and test data. A small turbocharged engine was tested to model the air transfer process. Turbine speed was measured with temperatures, pressures and air mass flow. Turbine speed response is like a first order system to air mass flow into a combustion chamber. The pressure ratio at the compressor is approximated by a curve proportional to the turbine speed square. Based on those findings, a reduced order model for describing dynamic air transfer process with a turbocharger was constructed. The proposed model is compact and suitable for engine torque control design and controller implementation.

Engine torque profile shaping strategies have been proposed to reduce noise & vibration for passenger cars. However, it has not been sufficiently studied that feasible torque profile for vibration suppression is dependent on engine speed and target torque shape. On the other hand, combustion pressure profile shaping strategies have been proposed to reduce noise. However, there is almost no research of the quantitative evaluation of contribution of combustion pressure profile. First, the torque profile shaping was studied. Pre-compensated torque and 2-step torque were selected as typical target torque profiles. An effectiveness of vibration suppression by two torque profiles was evaluated by both drivetrain vibration model and engine torque profile model which have been established well. As a result of studying the torque profile shaping, timing of torque rise by the 2-step torque generation is delayed or advanced.

OBD (On Board Diagnosis) has been applied to detect malfunctions in powertrains. OBD requirements have been extended to detect various failures for ensuring the vehicle emission control system being normal. That causes further costs for additional sensors and software works. Two layers diagnosis system is proposed for a passenger car gearbox system to detect changes from normal behavior. Conventional physical constraints based diagnosis is placed on the base layer. Model based diagnosis and specific symptom finding diagnosis are built on the second layer. Conventional physical constraints based diagnosis is direct and effective way to detect the failure of system if the detected signals exceed their normal ranges. However under the case of system failure with related signals still remain in normal ranges, the conventional detection measures can not work normally. Under this case, Model based diagnosis is proposed to enhance the functionality of diagnosis system.

New systems or functionalities have been rapidly introduced for fuel economy improvement. Active vibration suppression has also been introduced. Control algorithm is required to be verified in real time environment to develop controller functionality in a short term. Required frequency domain property concept is proposed for representation of target phenomena with reduced models. It is shown how to select or reduce engine, transmission and vehicle model based on the concept. Engine torque profile which has harmonics of engine rotation is required for engine start, take-off from stand still, noise & vibration suppression and misfire detection for OBD simulation. An engine model which generates torque profile synchronous to crank angle was introduced and modified for real time simulation environment where load changes dynamically. Selected models and control algorithms were modified for real time environment and implemented into two linked universal controllers.

Rapid Controller Prototyping (RCP) is an efficient method for design & development of ECU (Electronic Controller Unit) at early stage. Usually, RCP requires firstly performing Software-in-the-loop simulation and then connecting universal controller (e.g. MicroAutoBox) to real controlled system for testing of controller functionality. During this process, it is likely that some problems related to signal configuration and real time characteristics occur and consequently give rise to unexpected results, e.g., sensor signals or controlling signals produce large deviation and possibly damage components of real system under severe condition. On the other hand, it cannot make sure that the real time characteristics of designed controller are suitable just after applying Software-in-the-loop simulation.

Powertrain diagnosis technology has been developed for On Board Diagnostics (OBD) legal requirements and for failure identification of electronic controllers. The diagnosis technology can be sophisticated as there are requirements for compliance with stringent OBD regulations for early repair work for failure recovery or for real time deterioration compensation. Deterioration of performance, such as piece-to-piece variation of products or aging must be detected and identified to satisfy requirements. One of the promising methodologies has long been to compare detected values with model behaviors. Calculation time was a major constraint ten years ago. Model structure and sensor properties are likewise constraints even today. Model based diagnosis technology has been studied in the literature listed in references. The residual method was selected for the model based diagnostic method.