Early Detection of Product Reliability Based on the Parameters of the Production Line and Warranty Data

Reliability is one of the key dimensions of the quality of services and products that should be always evaluated. Growth and development of industries can be achieved by appropriate reliability engineering of products. Companies should evaluate and predict the reliability of products and accordingly find and fix the potential problems. In this regard, early detection of reliability problems based on the parameters of the production line or quality test results can prevent future warranty costs. Early detection of reliability problems based on production process and test data has not gained much attention in the literature. Therefore, an early detection model for predicting the reliability of products according to their quality test results is proposed in this research. For this purpose, hot test and warranty data of car engines manufactured by an automotive company are utilized. This data are prepared to predict engine reliability after preprocessing and removing inefficient data. Then, engines are divided into two homogeneous clusters using particle swarm optimization (PSO) clustering algorithm. Afterwards, the data in these clusters are used to feed the Artificial Neural Network (ANN) to predict the reliability of the engines. The obtained results show that the proposed ANN-based method is able to predict the reliability of the engines based on engine kilometers operated and hot test results. Also, it is shown that the proposed method outperforms the Cox proportional hazards model which has previously been used for early detection of product reliability.

Cold flow testing of laboratory-scale hybrid rocket engine test apparatus.

A cold-flow experimental investigation is performed on the Ryerson University lab-scale hybrid rocket engine test apparatus, in order to gain a further understanding of transient phenomena affecting the engine’s hot test firing results to date. The hot test firing data was characterized primarily by noticeable thrust oscillation magnitudes at low frequency being measured by the test stand’s thrust-measuring load cell, relative to somewhat lower magnitude low-frequency pressure oscillations being measured by a head-end pressure transducer. The present investigation allows for the evaluation of the fluid-structure interaction behaviour of the rocket engine’s combustion chamber and upstream oxidizer feed-line/injection apparatus (along with the surrounding test stand structure). Pressurized air at a moderate temperature acts as the working fluid (rather than hot gas arising from combustion), passing through the internal flow system, and exiting at the engine’s exhaust nozzle. Cold flow tests are conducted at three different flow-regulating orifice-plate conditions upstream of the head-end injector: 1) unchoked, 2) marginally choked and, 3) choked, in order to potentially observe any trends in that regard, as tied to feed-system stability/instability. The cold flow test results, from the experimental time-dependent measurement of pressure, thrust and axial acceleration, in turn undergo FFT analyses to help identify any frequency-dependent trends in regard to transient behaviour. Hammer tests are conducted to further establish the relevant lower frequency natural modes of structural vibration of the test apparatus with the engine in position The potential applicability of Karabeyoglu’s well-known thermal lag-combustion-gasdynamic predictive model (for estimating a characteristic frequency), which captures to some degree the intrinsic low frequency combustion-based instability behaviour of hybrid rocket engines, is considered for the present test engine setup. There are some promising comparisons in terms of relevant frequencies of mechanisms in the 20 Hz range, mechanisms that might be coupling to produce a noticeably augmented oscillation condition (as was observed in the hot firing thrust measurements).

Cold flow testing of laboratory-scale hybrid rocket engine test apparatus.

A cold-flow experimental investigation is performed on the Ryerson University lab-scale hybrid rocket engine test apparatus, in order to gain a further understanding of transient phenomena affecting the engine’s hot test firing results to date. The hot test firing data was characterized primarily by noticeable thrust oscillation magnitudes at low frequency being measured by the test stand’s thrust-measuring load cell, relative to somewhat lower magnitude low-frequency pressure oscillations being measured by a head-end pressure transducer. The present investigation allows for the evaluation of the fluid-structure interaction behaviour of the rocket engine’s combustion chamber and upstream oxidizer feed-line/injection apparatus (along with the surrounding test stand structure). Pressurized air at a moderate temperature acts as the working fluid (rather than hot gas arising from combustion), passing through the internal flow system, and exiting at the engine’s exhaust nozzle. Cold flow tests are conducted at three different flow-regulating orifice-plate conditions upstream of the head-end injector: 1) unchoked, 2) marginally choked and, 3) choked, in order to potentially observe any trends in that regard, as tied to feed-system stability/instability. The cold flow test results, from the experimental time-dependent measurement of pressure, thrust and axial acceleration, in turn undergo FFT analyses to help identify any frequency-dependent trends in regard to transient behaviour. Hammer tests are conducted to further establish the relevant lower frequency natural modes of structural vibration of the test apparatus with the engine in position The potential applicability of Karabeyoglu’s well-known thermal lag-combustion-gasdynamic predictive model (for estimating a characteristic frequency), which captures to some degree the intrinsic low frequency combustion-based instability behaviour of hybrid rocket engines, is considered for the present test engine setup. There are some promising comparisons in terms of relevant frequencies of mechanisms in the 20 Hz range, mechanisms that might be coupling to produce a noticeably augmented oscillation condition (as was observed in the hot firing thrust measurements).

An Improved Design of the Engine Bench Test Tool for the Dual Mass Flywheel (DMF)

At present, a lot of passenger cars and light trucks are equipped with the dual mass flywheel, which can decrease the non-uniformity of the indicated engine torque. In engine bench test, the secondary mass of the dual mass flywheel can’t be fixed because there is no transmission system on the test bench. As a result, the secondary mass of the dual mass flywheel will have radial and circumferential movements, which may lead to a damage to the dual mass flywheel. This paper presents an improved design of the crafting tool for the dual mass flywheel to protect the secondary mass during the engine bench test. For the improved design, the cylinder body is used for the positioning of the crafting tool, and a spline shaft and a ball bearing of centripetal adjustment are chosen to fix the secondary mass. Through this tool, the dual mass flywheel engine can be tested on the test bench without a starting shaft, and the disassembling of the engine flywheel bolts during the hot test can be avoided.