Comments on: VARIABLE FLOW OIL PUMPS http://www.ret-monitor.com/articles/624/variable-flow-oil-pumps/ Specific mission-critical info for professionals Thu, 09 Feb 2012 16:57:30 +0000 http://wordpress.org/?v=2.7.1 hourly 1 By: Mikey http://www.ret-monitor.com/articles/624/variable-flow-oil-pumps/comment-page-1/#comment-8056 Mikey Thu, 23 Jun 2011 05:40:47 +0000 http://www.ret-monitor.com/articles/624/variable-flow-oil-pumps/#comment-8056 So what was the solution Chevrolet provided with the Ecotec 1.4 L ? The only description I've found in a brief search almost sounded like double-speak that somewhat explains "what" it supposedly does but doesn't really touch on the "how". It reads: Variable-Flow Oil Pump The Ecotec 1.4L turbo uses a unique variable-flow oiling system that helps maximize fuel efficiency. Rather than the linear operation of a conventional fixed-flow pump, it is accomplished with a crankshaft-driven oil pump that matches the oil supply to the engine load. The Ecotec 1.4L turbo's variable-flow pump changes its capacity based on the engine’s demand for oil. This prevents using energy to pump oil that is not required for proper engine operation. Just curious. ?_? So what was the solution Chevrolet provided with the Ecotec 1.4 L ? The only description I’ve found in a brief search almost sounded like double-speak that somewhat explains “what” it supposedly does but doesn’t really touch on the “how”. It reads:

Variable-Flow Oil Pump
The Ecotec 1.4L turbo uses a unique variable-flow oiling system that helps maximize fuel efficiency. Rather than the linear operation of a conventional fixed-flow pump, it is accomplished with a crankshaft-driven oil pump that matches the oil supply to the engine load. The Ecotec 1.4L turbo’s variable-flow pump changes its capacity based on the engine’s demand for oil. This prevents using energy to pump oil that is not required for proper engine operation.

Just curious. ?_?

]]> By: Terry http://www.ret-monitor.com/articles/624/variable-flow-oil-pumps/comment-page-1/#comment-6163 Terry Thu, 20 Jan 2011 08:08:14 +0000 http://www.ret-monitor.com/articles/624/variable-flow-oil-pumps/#comment-6163 Assuming oil temperatures and pressures are constant, oil flow rates through crank journal bearings don't change appreciably with rpm, since the bearing clearance (ie. the orifice flow area) doesn't change. Journal bearing oil flow rates are based on cooling requirements, so bearing oil flows should be highest when engine power is highest. As noted, a variable displacement oil pump would be beneficial for automotive engines. But not really so much for a racing engine. The reason for this is that racing engines run mostly at WOT, and automotive engines run mostly at limited part throttle. A typical automotive engine oil pump might use less than 2 HP. The pump is a fixed displacement device, runs at a fixed speed ratio relative to engine speed, and is sized for flows needed for WOT operation. But that same engine also only produces about 20 HP most of the time it operates. So the oil pump loss typically amounts to 10% of the BHP output of the engine. With a 600 HP race engine that operates mostly at WOT, a 2 or 3 HP oil pump loss is not a big deal. Assuming oil temperatures and pressures are constant, oil flow rates through crank journal bearings don’t change appreciably with rpm, since the bearing clearance (ie. the orifice flow area) doesn’t change. Journal bearing oil flow rates are based on cooling requirements, so bearing oil flows should be highest when engine power is highest.

As noted, a variable displacement oil pump would be beneficial for automotive engines. But not really so much for a racing engine. The reason for this is that racing engines run mostly at WOT, and automotive engines run mostly at limited part throttle.

A typical automotive engine oil pump might use less than 2 HP. The pump is a fixed displacement device, runs at a fixed speed ratio relative to engine speed, and is sized for flows needed for WOT operation. But that same engine also only produces about 20 HP most of the time it operates. So the oil pump loss typically amounts to 10% of the BHP output of the engine.

With a 600 HP race engine that operates mostly at WOT, a 2 or 3 HP oil pump loss is not a big deal.

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