This paper describes a unique design concept that is capable of electronically controlling the flow delivered by an external gear pump (EGP). The principle used for varying the flow relies on the variable timing concept which has been previously demonstrated by the author's research team for EGP's operating at high pressures (HPs) (p > 100 bar). This principle permits to vary the flow within a certain range, without introducing additional sources of power loss. In this paper, the above concept has been applied to formulate a design for a variable delivery EGP for low pressure (LP) applications (p < 30 bar), suitable for direct electric actuation. Specific design principles for the gear and the flow variation mechanisms are introduced to limit the force required by the electric actuation, and for maximizing the flow variation range. Also, the low target pressure allows the variable timing principle to be realized with an asymmetric solution, with only one variable timing element present at one side of the gears. A detailed analysis concerning the relationship between the electrically commanded position of the flow varying element and the theoretical flow delivered by the pump is also presented. This analysis is used to formulate analytical expressions for the instantaneous flow rate and the flow nonuniformity of the pump. The paper details the design principle of the proposed variable flow pump and describes the multi-objective optimization approach used for sizing the gears and flow variation mechanism. The paper also discusses the experimental activity performed on a prototype of the proposed unit, able to achieve a flow variation of 31%.

References

References
1.
Rundo
,
M.
, and
Nervegna
,
N.
,
2015
, “
Lubrication Pumps for Internal Combustion Engines: A Review
,”
Int. J. Fluid Power
,
16
(
2
), pp.
59
74
.
2.
Zavadinka
,
P.
,
2015
, “
Development of a Variable Roller Pump and Evaluation of Its Power Saving Potential as a Charge Pump in Hydrostatic Drivetrains
,” Ph.D. thesis, Vysoké učení technické, Brno, Czechia Republic.
3.
Yang
,
D.
, and
Zhong
,
D.
,
1987
, “
Radial-Movable Variable Displacement Gear Pump (Motor)
,” Patent No. CN85109203.
4.
Reiners
,
W.
, and
Wiggermann
,
W.
,
1960
, “
Variable Delivery Gear Pumps
,” WALTER REINERS, Cologne, Germany, Patent No.
GB968998
.https://patents.google.com/patent/GB968998A/en?oq=GB968998
5.
Winmill
,
L.
,
2000
, “
Adjustable-Displacement Gear Pump
,” U.S. Patent No.
09/734,326
.https://patents.google.com/patent/US20010024618
6.
Bussi
,
E.
,
1992
, “
Variable Delivery Gear Pump
,” Parker-Hannifin Corp., Cleveland, OH, European Patent No.
EP0478514
.https://patents.google.com/patent/US20090088280
7.
Hoji
,
T.
,
Nagao
,
S.
, and
Shinozaki
,
K.
,
2010
, “
Gear Pump
,” TBK Co Ltd., Machida, Tokyo, U.S. Patent No.
7,717,690
.https://patents.google.com/patent/US7717690B2/en?oq=7%2c717%2c690
8.
Nervegna
,
N.
,
2003
,
Oleodinamica e Pneumatica
,
Politeko
,
Torino, Italy
.
9.
Nieling
,
M.
,
Fronczak
,
F.
, and
Beachley
,
N. H.
,
2005
, “
Design of a Virtually Variable Displacement Pump/Motor Ncfp i05-10.1
,”
National Conference on Fluid Power
, Las Vegas, NV, Mar. 16–18, p.
323
.
10.
Hintzsche
,
T.
,
Engineer
,
H. R.
,
Concentric
,
A.
, and
Rockford
,
I.
,
2016
, “
Variable Flow Rotor Pump
,”
Fluid Power Innovation & Research Conference
, Minnesota, USA.http://nfpahub.com/events/wp-content/uploads/sites/2/2016/10/FPIRC-TROY.VFRP_10Oct2016-2.pdf
11.
Voigt
,
D.
,
2011
, “
Variable Flow Spur Gear Oil Pump for Utility Vehicle Engines
,”
MTZ Worldwide eMagazine
,
72
(
4
), pp.
24
29
.
12.
Devendran
,
R. S.
, and
Vacca
,
A.
,
2014
, “
A Novel Design Concept for Variable Delivery Flow External Gear Pumps and Motors
,”
Int. J. Fluid Power
,
15
(
3
), pp.
121
137
.
13.
Vacca
,
A.
, and
Devendran
,
R. S.
,
2016
, “
A Flow Control System for a Novel Concept of Variable Delivery External Gear Pump
,”
Tenth International Fluid Power Conference
, Dresden, Germany, p. 13.http://tud.qucosa.de/api/qucosa%3A29357/attachment/ATT-0/
14.
Vacca
,
A.
, and
Devendran
,
R. S.
,
2016
, “
Variable Delivery External Gear Machine
,” Purdue Research Foundation, West Lafayette, IN, U.S. Patent No.
15/121,586
.https://patents.google.com/patent/US20160369795A1/en?oq=15%2f121%2c586
15.
Devendran
,
R. S.
, and
Vacca
,
A.
,
2017
, “
Theoretical Analysis for Variable Delivery Flow External Gear Machines Based on Asymmetric Gears
,”
Mech. Mach. Theory
,
108
(
Suppl. C
), pp.
123
141
.
16.
Tankasala
,
S.
, and
Vacca
,
A.
,
2017
, “
A Solution for an Electronically-Controlled Variable Delivery External Gear Pump
,”
ASME
Paper No. FPMC2017-4328.
17.
Zhao
,
X.
, and
Vacca
,
A.
,
2017
, “
Formulation and Optimization of Involute Spur Gear in External Gear Pump
,”
Mech. Mach. Theory
,
117
, pp.
114
132
.
18.
Vacca
,
A.
, and
Tankasala
,
S.
,
2018
, “
A Controlled Variable Delivery External Gear Machine
,” U.S. Patent No. 15/993,505.
19.
Ivantysyn
,
J.
, and
Ivantysynova
,
M.
,
2001
,
Hydrostatic Pumps and Motors
,
Academic Books International
,
New Delhi, India
.
20.
Zhao
,
X.
, and
Vacca
,
A.
,
2017
, “
Numerical Analysis of Theoretical Flow in External Gear Machines
,”
Mech. Mach. Theory
,
108
(
Suppl. C
), pp.
41
56
.
21.
Huang
,
K. J.
, and
Lian
,
W. C.
,
2009
, “
Kinematic Flowrate Characteristics of External Spur Gear Pumps Using an Exact Closed Solution
,”
Mech. Mach. Theory
,
44
(
6
), pp.
1121
1131
.
22.
Devendran
,
R. S.
, and
Vacca
,
A.
,
2013
, “
Optimal Design of Gear Pumps for Exhaust Gas Aftertreatment Applications
,”
Simul. Modell. Pract. Theory
,
38
, pp.
1
19
.
23.
Vacca
,
A.
, and
Guidetti
,
M.
,
2011
, “
Modelling and Experimental Validation of External Spur Gear Machines for Fluid Power Applications
,”
Simul. Modell. Pract. Theory
,
19
(
9
), pp.
2007
2031
.
You do not currently have access to this content.