Evaluation of the proposed method for inertia moments of vehicle powertrain parts measuring by acceleration and deceleration

Abstract

The scheme of energy transmission from the engine to the wheels of the car is considered. It is indicated that the dynamics of the vehicle when driving in low gears is significantly influenced by the value of the moment of inertia of equivalent masses. For a passenger car, when driving in first gear, the equivalent weight can increase up to 28%. In the literature, inertial masses are determined approximately.

The article proposes a simple technique for assessing the moments of inertia of the main parts (wheels, transmission, engine) without disassembling the car. The essence of the method is to measure the deceleration during free run of the car with the vehicle's wheels hanging, and then without the wheels.

A system of equations for the power balance of the vehicle run-out in 3rd and 4th gears of the gearbox with open clutch is compiled. When drawing up the equation, it was assumed that with the same engine speed and the same throttle opening, the engine torque would be the same. Formulas are obtained for calculating the moment of inertia of the wheels and the variable part of the transmission, according to which the inertial mass of the engine is calculated without the need to remove it from the machine. The article describes the experimental research methodology applied to the Hyundai i30 car with a working volume of 1.4 liters, manufactured in 2007. In the course of the experiment, the engine speed was measured through the OBD II connector, using the ELM 327 adapter and the ScanMaster-ELM program, the vehicle on-road speed using the Garmin eTrex 30 navigator, and the wheel revolutions were recorded on video. During the experiment, the condition of the tires Nokian Nordman SX 195/65 R15 91H was monitored, for which the residual depth of the tire tread pattern, pressure, moment of inertia were determined (by the bifilar suspension method). Based on the results of the experiment, the developed mathematical model was used to calculate the moment of inertia of the rotating parts of the Hyundai i30 in different gears. The result of the study allows you to establish the actual state of the rotating parts of the car, the knowledge of which increases the accuracy of determining the performance characteristics.

The technique can be used to diagnose the conditions of transmission elements and car wheels. The technique does not require the use of complex stands and expensive devices.