A model for simulating the instantaneous crank kinematics and total mechanical losses in a multicylinder in-line engine

Abstract

A two-degree-of-freedom dynamic model is constructed to simulate the instantaneous crank kinematics and total mechanical losses arising in a multicylinder gasoline engine coupled to a dynamometer. The simulation model is driven using specified cylinder gas pressures, and loaded by nominal brake torque and total friction losses. Existing semi-empirical torque loss models (based on calibrated single-cylinder diesel engine data) are used to account for the instantaneous friction losses in the piston-ring assembly, in bearings, and in auxiliaries. The model is specialized to the simulation of crank kinematics and matched brake torque for a three-cylinder in-line direct injection spark ignition (DISI) engine, without a gearbox. This allows the total friction loss to be separated from the brake torque for an engine not fitted with the very large number of sensors otherwise needed to calibrate analytical friction models. An equivalent simulation model is also constructed using GT-Crank, which excludes explicit reference to friction. In using both models to simulate steady state operation at a specified mean engine speed, the output torque is matched by iteration. The GT-Crank model necessarily compensates for internal losses by exaggerating the total output torque. Both simulation models are compared with measured crank kinematics and brake torque obtained from a dynamometer-loaded I3 DISI engine. The paper shows that by comparing the matched output torque from simulation with the measured output torque from the engine, the proposed model gives a very good high-speed prediction of the total mechanical losses. At low speed, the instantaneous model is still not accurate. It is also shown, however, that apart from the no-load condition, use of an average torque to compensate for friction (as in GT-Crank) is wholly acceptable for simulating instantaneous crank kinematics. This is the first reported instance of a simulation model (which includes the particular form of semi-empirical friction loading) being comprehensively compared and verified using multicylinder DISI engine data.

Engine cylinder pressure reconstruction using crank kinematics and recurrently-trained neural networks

“…Construction of a dynamic model in the form of a differential equation [26] allows a description of the instantaneous crank motion of an IC engine to be driven by the engine cylinder pressures. This model assumes that all the engine sub-models, and their associated parameters, are known in detail, including the slider-crank mechanism geometry, mass and inertial values, friction properties, and the instantaneous engine load torque.…”

“…It was shown in [26] and [30] that the recurrent NARX architecture offers great promise for accurate cylinder pressure reconstruction, but robust and efficient training is needed. Both BPTT, and the Extended Kalman Filter (EKF), were shown in [26] and [4] to be too slow.…”

Modelling of Contact Between Stiff Bodies in Automotive Transmission Systems

“…For instance, dynamic simulations of crankshaft or connecting rods have been carried out in [18] to analyse the mechanical losses; the study of deformations and stresses are available in [7,17] for global multicylinder engines. The suspensions are also widely modelled using multibody tools [3].…”

Dynamic interaction between the structure and the trolley of high performance gantry cranes

“…U literaturi se mogu naći i radovi u kojima su korišćeni i redukovani dinamički modeli. Modeli kolenastog vratila sa dva stepena slobode (2DOF) mogu se naći u radovima Zveirija (Zweiri) [8,9], Potence (Potenza) [10] i Konolija i Jagla (Connoly, Yagle) [11].…”

“…2DOF modeli  2 Degrees Of Freedom) [5,[8][9][10][11]20,[191][192][193][194]. Pojednostavljen šematski prikaz tog slučaja dat je na Sl.…”