1. A lubricant oil circulation system for circulation of lubricant oil of an electric motor in a hybrid electric vehicle that is powered by and has, as power sources, the electric motor operable on electric power supplied from an electrical storage device and an internal combustion engine, comprising:
an electric pump operable on electric power stored in the electrical storage device to circulate the lubricant oil in an oil flow path that includes the electric motor interior structure;
a mechanical pump operable on driving power of the internal combustion engine to circulate the lubricant oil in the oil flow path; and
a controller configured to detect abnormality in operation of the electric pump derived from viscosity of the lubricant oil and to use operation of the mechanical pump on driving power of the internal combustion engine upon detecting the abnormality in operation of the electric pump.
2. The oil circulation system according to claim 1, wherein the mechanical pump is made to have such a structure as to receive the amount of heat from the internal combustion engine.
3. The oil circulation system according to claim 1, wherein, the controller causes the mechanical pump to keep on operating for a predetermined duration of time immediately after detecting that the abnormality of the mechanical pump has been eliminated and shuts down the mechanical pump upon lapse of the predetermined period of time.
4. The oil circulation system according to claim 1, wherein the controller adjusts rotational speed of the mechanical pump in response to rotational speed of the electric pump after the electric pump has started so that flow rate of the lubricant oil remains lower than a predetermined flow rate.
5. The oil circulation system according to claim 1, further comprising: an oil cooler in the oil flow path; a detour around the oil cooler and a flow path switching valve for switching between the oil cooler and the detour, and
wherein the controller executes switching control of the flow path switching control valve so that the lubricant oil passes through the detour around the oil cooler upon detecting the abnormality in operation of the electric pump.
6. The oil circulation system according to claim 1, wherein the hybrid electric vehicle is operable in a drive mode in which only the electric motor powers the vehicle or in another drive mode in which at least the internal combustion engine powers the vehicle, and
the controller prohibits the vehicle operation in the drive mode in which only the electric motor powers the vehicle, but allows the vehicle operation in another drive mode in which at least the internal combustion engine powers the vehicle upon detecting the abnormality in operation of the electric pump.
7. The oil circulation system according to claim 1, wherein the electric pump is in fluid communication with the oil flow path and the mechanical pump is in fluid communication with the oil flow path, and the mechanical pump is drivably connected to the internal combustion engine.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for producing sintered titanium dioxide pellets comprising:
(a) mixing water and titanium dioxide dust in a high intensity mixer to form the titanium dioxide dust directly into substantially round and spherical green pellets;
(b) drying the titanium dioxide green pellets; and
(c) sintering the dried titanium dioxide pellets at 850\xb0 C. to about 1050\xb0 C.;
wherein the sintered titanium dioxide pellets have a substantially round and spherical shape that measures at least about 0.8 on the KrumbeinSloss Roundness and Sphericity Chart.
2. The method according to claim 1 further comprising mixing a binder with the water and titanium dioxide dust.
3. The method according to claim 1 further comprising screening the substantially round and spherical green pellets prior to sintering.
4. The method according to claim 1 further comprising screening the sintered pellets.
5. The method of claim 1 wherein the titanium dioxide dust comprises at least about 90% titanium dioxide.
6. The method of claim 2 wherein the binder is selected from polyvinyl alcohol and starch.
7. The method of claim 1 wherein the sintered pellets have a bulk density from between about 1.38 gcc to about 2.46 gcc.
8. The method of claim 1 wherein the sintered pellets have a bulk density from between about 1.63 gcc to about 2.46 gcc.