actual gains from new Variable Displacement oil pumps?

[gary505]

Does anyone have actual numbers on the energy saved by using the new variable displacement oil pumps versus the current styles being used today. How much gain is there and are they as reliable as the current design. I see several potential problems with the design being used in the the Chevy Cruz.The electric solenoids being used for the variable cam timing become stuck because of dirt or contamination in the oil even with the most diligent oil changers in todays cars,can we chance that on a new design that is the life on the engine????

 

[BrianPetersen]

It is a vane pump with a spring-loaded housing as opposed to the current gerotor design. It has more moving parts, true, but they are not rocket science. Variable vane pumps of this type have already been used in automatic transmissions for years. Supposedly the gain in fuel consumption is one percent or thereabouts, but this is a fairly cheap percent to find.

I'm not aware of valve timing solenoids being a huge reliability issue in general, excluding situations of gross neglect. Care to point out any evidence of that?

Sludging through use of inadequate oil, neglect, short trips, etc will be an expensive situation to fix. Some engine manufacturers have very specific engine oil requirements nowadays. Taking the car to the local quickie lube where a minimum-wage worker who doesn't read labels is doing the oil change, might not be a good idea in the long term. Buying the cheapest oil at the local auto parts place won't be such a good idea, either. Folks who don't know what the phrase "oil change" means, are going to get penalized heavily, too.

 

[tbuelna]

gary505,

A variable displacement oil pump can actually have a pretty significant benefit for highway fuel consumption rates. You have to consider the oil pump parasitic losses in terms of the percentage of power going to propel the vehicle. Just as an example, if your little economy car needs 20HP to cruise down the highway at 60MPH, and the variable displacement oil pump uses 0.50HP less than a fixed displacement oil pump under the same conditions, then that amounts to a reduction in fuel consumption of around 2%. That's a worthwhile gain with today's vehicles, and at a modest cost increase.

Regards,
Terry