Method and device for controlling the oil supply of an automatic gearbox and a starting element

A method of controlling a supply of oil to an automatic transmission and a starting element of a vehicle, the method comprising the steps of:

• providing at least first and second oil pumps (2, 3) for supplying oil to at least one of a hydraulic control device of the automatic transmission and the starting element (11);
• mechanically driving the first oil pump (2) with an internal combustion engine (4) to provide an oil flow to a high pressure branch (14) of an oil supply assembly;
• electrically driving the second oil pump (3) to provide oil to the hydraulic control device at least when the internal combustion engine (4) is inactive and during at least one other operating condition;
• cooling the starting element (11) with an oil flow, provided by at least the electrically driven second oil pump (3) at least during a starting procedure of the vehicle, and the electrically driven second oil pump (3) providing pressure to a low pressure branch (15) of the oil supply assembly;
• and
• determining, with an oil flow demand sensor, at least one of:
• a current and a directly following oil volume demand for at least one of the hydraulic control device and the starting element (11),
• a current and a directly following demand of oil volume from the first oil pump (2), and
• an additional oil volume demand based on the demand of oil volume and an oil pump output from the first oil pump (2).

A method of controlling a supply of oil to an automatic transmission and a starting element of a vehicle, the method comprising the steps of:

• providing at least first and second oil pumps (2, 3) for supplying oil to at least one of a hydraulic control device of the automatic transmission and the starting element (11);
• mechanically driving the first oil pump (2) with an internal combustion engine (4) to provide an oil flow to a high pressure branch (14) of an oil supply assembly;
• electrically driving the second oil pump (3) to provide oil to the hydraulic control device at least when the internal combustion engine (4) is inactive and during at least one other operating condition;
• cooling the starting element (11) with an oil flow, provided by at least the electrically driven second oil pump (3), at least during a starting procedure of the vehicle, and the electrically driven second oil pump (3) providing pressure to a low pressure branch (15) of the oil supply assembly, and
• at least one of:
• during a first one of the at least one other operating condition in which the first oil pump (2) is not being driven by the internal combustion engine (4) and the second oil pump (3) is being driven,
• activating a switching valve (13) to suppress an oil flow from the second oil pump (3) to a transmission lubricating oil supply (10) and the oil provided to cool the starting element (11) whereby oil is prevented from flowing into a common oil reservoir (1) through the first oil pump (2), and
• providing pressurized oil from the second oil pump (3) and via a pressure regulator (8) to shifting elements of the automatic transmission such that the shifting elements will be one of prefilled and retained as prefilled;
• during a second one of the at least one other operating condition in which the first oil pump (2) is being driven by the internal combustion engine (4) and the second oil pump (3) is being driven,
• passing the oil flow for cooling the starting element (11) through an at least substantially open switching valve (13) to the starting element (11),
• controlling a main pressure valve (6) to allow a shifting pressure to be applied to a pressure regulator (8), wherein the shifting pressure is sufficient to shift at least one shifting element of the transmission,
• passing an oil flow through the main pressure valve (6) to the switching valve (13) at a pressure lower than the oil flow passing through the main pressure valve (6) to the pressure regulator (8),
• combining an oil flow form the second oil pump (3) that is necessary for cooling the starting element (11) with the oil flow from the first oil pump (2);
• and
• during a third one of the at least one operating condition in which the first oil pump (2) is being driven by the internal combustion engine (4) and the second oil pump (3) is not being driven,
• actuating a switching valve (13) to pass the oil flow to a transmission lubricating oil supply (10) and to substantially prevent passage of the oil flow to the starting element (11),
• actuating a main pressure valve (6) to allow a shifting pressure to be applied to a pressure regulator (8), wherein the shifting pressure is sufficient to shift at least one shifting element of the transmission,
• passing an oil flow through the main pressure valve (6) to the switching valve (13) at a pressure lower than the oil flow passing through the main pressure valve (6) to the pressure regulator (8), and
• by operation of a check valve (7) located downstream from the second oil pump (3), preventing passage of the oil flow from the second oil pump (3) due to the pressure of the oil flow passed through the main switching valve (6).

An assembly for controlling oil supply to an automatic transmission and a starting element of a vehicle the assembly comprising:

• a first oil pump (2), located within a high pressure branch (14), being mechanically driven by an internal combustion engine (4) to supply an oil flow under high pressure;
• a second oil pump (3), located within a low pressure branch (15), being electrically driven by an electric motor (5) to supply an oil flow under low pressure;
• a pressure regulator (8), located within the high pressure branch (14), for shifting at least one transmission shifting element;
• an oil cooler (12), transmission lubrication elements (10), and a starting element cooler (11) being located within the low pressure branch (15);
• a high pressure valve (6), located within the main pressure line (14), for adjusting the oil flow under high pressure supplied by the first oil pump (2);
• and
• a connecting line (16) being to a low pressure outlet of the high pressure valve (6) and the low pressure branch (15) such that the high pressure branch (14) being connected to the low pressure branch (15).