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Emerging trend in the automotive industry all around the world is to develop vehicles to consume less fuel and to meet stringent emission norms by using engines of higher power to weight ratio and higher thermal efficiency. These advanced technology engines designed for high power output will use low viscous oil to reduce frictional losses and will operate at elevated temperature levels. Hence, the various auxiliaries and parts of these engines should be adaptable for the use of low viscous oil and should withstand higher temperatures. Oil pump is one such auxiliary which will be subjected to work with low viscous oil at higher temperatures levels. The oil pump taken for study and design improvement is an internal gear type positive displacement oil pump, used in a passenger car diesel engine. The un-meshing of the gears causes the inflow and meshing causes the outflow of lubricating oil. This process occurs continuously for providing a smooth pumping action.

Vacuum pumps are predominantly used in diesel engines of passenger cars and trucks for generating vacuum in servo brake applications. With the emission norms getting stringent, there is a need for vacuum signal for EGR actuation, turbo-charger waste gate actuation and other servo applications. These multi-functional applications of vacuum pumps and the functional criticality in application like braking system demand an effective and reliable performance. In gasoline engines, the vacuum generated in the intake manifold is tapped for braking. The recent technology of gasoline direct injection compels the use of vacuum pump in gasoline engines also due to scarce vacuum in intake manifold. The performance of the vacuum pump is highly dependent on the opening and closing of the check valve sub-system, which is positioned between the vacuum reservoir and the pump at the suction side.

Vacuum pump is a device which gets the drive from engine cam shaft. In some designs, it is driven by the alternator shaft. The main function of vacuum pump is to evacuate the air from the brake booster tank, thus creating vacuum, which can be used for brake application. In addition to this, in new generation engines, to meet the Euro V emission targets, vacuum pump also has to create vacuum in the auxiliary tank which will be used to actuate the turbo charger waste gate actuation mechanism and EGR valve. The vacuum pump used for brake application when modified to perform the additional function of turbocharger may deteriorate the primary application performance. The tapping position and the size of the vacuum port for the auxiliary tank will influence the primary braking performance of the pump. The work described in this paper involves the systematic analysis of layout study of vacuum pump to meet the performance of the vehicle for brake and turbocharger applications.

The main challenge in designing the oil pump for gasoline & diesel engines is to optimize the pressure relief passage. Pressure relief passage is critical from design point of view as it maintains the oil pressure in the engine. Optimal levels of oil pressure and flow are very important for satisfactory performance and lubrication of various engine parts. Low oil pressure will lead to seizure of engine and high oil pressure leads to failure of oil filters, gasket sealing, etc. Optimization of pressure relief passage area will also reduce the power consumed by the pump. The Pressure relief system for this study consists of Pressure relief valve, spring, retainer, pressure relief passages. It is difficult to directly measure the flow through the pressure relief passage and is arrived based on the drop in flow at the delivery port. Numerical tool will be handy to predict the flow through the pressure relief passage and this can be used to optimize the flow through the bypass passage.

In today’s scenario, both in gasoline and diesel engines, it is important to reduce power consumed by the auxiliary devices causing parasitic loss. Oil pump is one such device, used for lubrication purpose, which consumes higher power developed by the engine causing parasitic loss. Conventionally gerotor construction pumps are predominantly used in majority of engines, owing to its simpler construction, lower NVH and cost. However, this type being a positive displacement pump, consumes higher power with increase in speed. Hence, variable displacement oil pumps are gaining importance as the oil flow rate can be varied over the entire engine operating range. In this work, basic design elements of variable displacement oil pump are identified followed by building of mathematical model to calculate the critical design parameters. The basic mathematical model built can calculate oil flow rate, leakage losses and power consumption at different speed and load conditions.

The main challenge in today's modern engines is to design the parts, which should withstand higher temperatures. To achieve this, selection of materials and process tolerances are very important factors. The product identified in this study is a conventional oil pump, which is an engine auxiliary component. The function of the oil pump is to supply oil to different parts of the engine to lubricate and reduce the overall engine friction. The different speed and load conditions for which the engine is subjected, pose a challenge to the oil pump, to supply the necessary quantity of oil at the required pressure and temperature. Normally, the oil pump is subjected to a temperature of 120°C at higher speeds. However, the peak oil temperature in modern diesel engines can be as high as 140°C to 150°C for a short period of time. For this study, two engine grade oils were selected. Numerical analysis was performed to predict the oil flow rate for these oil grades.