Engines and lubrication systems do not typically use piston-type pumps as oil pumps because of their intricacy and cost implications in comparison to other pump types like gear or vane. Here’s a more detailed explanation:
- Complex Design: Piston pumps have greater intricate design with many moving parts compared to gear or vane pumps, besides this complexity increases the starting manufacturing costs but also makes maintenance more complicated and expensive. In regard with oil pumps which are expected to be highly reliable over an engine’s lifetime, the simplicity and durability of gear and vane pumps would be better.
- Cost Considerations: They are often less expensive than piston designs due to having less components that therefore means lower production costs, making it a cost-effective approach for engines produced in huge amounts. In the competitive automotive industry, keeping production costs low while maintaining reliability is a priority.
- Efficiency: Gear and vane pumps provide sufficient efficiency for circulating oil and can maintain a consistent flow that is essential for engine lubrication purposes. However, piston pumps can offer high levels of precision as well as variable pressure and flow rates that are not needed by basic operation of oil pump in an engine.
- Size and Space: Generally, piston pumps are bigger devices that require more space unlike gear or vane pumps; hence smaller components must be used within the constraints of an engine compartment. Gear and vane types can be made compact enough to fit within an engine layout without affecting performance significantly.
- Operating Environment: Oil is pumped in stable conditions where demand for flow rate/pressure does not change much during an operating cycle. The simpler styles of gears/vanes will suffice since there is no requirement for these advanced functions found on pistons.
- Durability/Wear: Unlike piston pumps, gears/vanes can handle contaminants present in oils better. These types do not wear out quickly when subjected to harsh conditions typical of engines with particle laden oils.
- Noise Levels: Piston movement may generate more noise, which can be undesirable in a passenger vehicle. Typically, gear and vane designs operate quietly making it better for driving.
In conclusion, piston-type pumps are highly versatile and can be used for many different high-pressure applications requiring fine control. Nevertheless, their complexity, cost, size and efficiency characteristics make them less suitable as engine oil pumps. For continuous but less variable demands of engine oil circulation, gear and vane pumps provide a more streamlined cost-effective solution.
