System for controlling the state of a flow control valve

A temperature control system for engine warm-up or start-up in a liquid cooled internal combustion engine equipped with a radiator, the system comprising:

• (a) a first flow control valve for controlling flow of a temperature control fluid through a first passageway which communicates with the radiator, the first flow control valve having a first state for preventing said flow and a second state for allowing said flow;
• (b) a first sensor for measuring the temperature of the temperature control fluid, t1;
• (c) a second sensor for measuring ambient air temperature, t2;
• (d) a third sensor for measuring an actual engine operation temperature indicative of engine oil temperature;
• (e) an engine computer for receiving signals from the first and second sensors, producing control signals based on both of said sensor signals, and sending said control signals to the first flow control valve to control the state of the valve,
• t1 and t2 defining a first mathematical function of t1=f(t2) which forms a first two-dimensional curve on an orthogonal coordinate system having axes t1 and t2, the first curve dividing the coordinate system into two regions, one on either side of the first curve, the engine computer sending said control signals to place the valve in the first state when coordinate pairs of t1 and t2 lie on a first region of the coordinate system and sending said control signals to place the valve in the second state when coordinate pairs of t1 and t2 lie on a second region of the coordinate system defined by the first curve,
• t1 and t2 also defining a second mathematical function of t1=f(t2) which forms a second two-dimensional curve on the orthogonal coordinate system having axes t1 and t2, the second curve dividing the coordinate system into two regions, one on either side of the second curve, the engine computer sending said control signals to place the valve in the first state when coordinate pairs of t1 and t2 lie on a first region of the coordinate system defined by the second curve and sending said control signals to place the valve in the second state when coordinate pairs of t1 and t2 lie on a second region of the coordinate system defined by the second curve;
• (f) means for comparing the measured engine operation temperature to a preselected engine operation temperature;
• and
• (g) means for selecting either the first or second curve to control the state of the valve, the first curve being selected during engine start-up or warm-up, the second curve being selected when the actual engine operation temperature reaches the preselected temperature.

A method for controlling the state of a flow control valve in an internal combustion engine equipped with a radiator and an engine computer, the flow control valve controlling flow of temperature control fluid, the method comprising the steps of:

• (a) measuring a temperature (t1) of the temperature control fluid with a first temperature sensor and sending t1 to the engine computer;
• (b) measuring an ambient air temperature (t2) with a second temperature sensor and sending (t2) to the engine computer;
• (c) measuring an actual engine operation temperature which is indicative of engine oil temperature with a third temperature sensor;
• (d) comparing the actual engine operation temperature to a preselected engine operation temperature;
• (e) defining a first mathematical function of t1=f(t2) which forms a first two-dimensional curve on an orthogonal coordinate system having axes t1 and t2, the first curve dividing the coordinate system into two regions, one on either side of the first curve;
• (f) defining a second mathematical function of t1=f(t2) which forms a second two-dimensional curve on an orthogonal coordinate system having axes t1 and t2, the second curve dividing the coordinate system into two regions, one on either side of the second curve;
• (g) selecting either the first or second curve to control the state of the valve, the first curve being selected when the actual engine operation temperature is at or below the preselected temperature, the second curve being selected when the actual engine operation temperature is above the preselected temperature;
• (h) determining in the engine computer which region of the coordinate system of the selected curve the measured temperatures t1 and t2 lie in;
• and
• (i) sending control signals from the engine computer to the valve to place the valve in either a first state for preventing said flow when coordinate pairs of t1 and t2 lie in the first region of the coordinate system of the selected curve, or in second state for allowing said flow when coordinate pairs of t1 and t2 lie in the second region of the coordinate system of the selected curve.

A method for controlling the state of a flow control valve during engine start-up or warm-up in an internal combustion engine equipped with a radiator and an engine computer, the flow control valve controlling flow of temperature control fluid, the method comprising the steps of:

• (a) measuring a temperature (t1) of the temperature control fluid with a first temperature sensor and sending t1 to the engine computer;
• (b) measuring an ambient air temperature (t2) with a second temperature sensor and sending (t2) to the engine computer;
• (c) measuring an actual engine operation temperature indicative of engine oil temperature with a third temperature sensor;
• (d) comparing the actual engine operation temperature to a preselected engine operation temperature;
• (e) defining a first mathematical function of t1=f(t2) which forms a first two-dimensional curve on an orthogonal coordinate system having axes t1 and t2, the first curve dividing the coordinate system into two regions, one on either side of the first curve;
• (f) defining a second mathematical function of t1=f(t2) which forms a second two-dimensional curve on an orthogonal coordinate system having axes t1 and t2, the second curve dividing the coordinate system into two regions, one on either side of the second curve;
• (g) selecting either the first or second curve to control the state of the valve, the first curve being selected during engine warm-up or start-up, the second curve being selected when the actual engine operation temperature reaches the preselected temperature;
• (h) determining in the engine computer which region of the coordinate system of the selected curve the measured temperatures t1 and t2 lie in;
• and
• (i) sending control signals from the engine computer to the valve to place the valve in either a first state for preventing said flow when coordinate pairs of t1 and t2 lie in the first region of the coordinate system of the selected curve, or in second state for allowing said flow when coordinate pairs of t1 and t2 lie in the second region of the coordinate system of the selected curve.

A temperature control system in a liquid cooled internal combustion engine for use during engine warm-up or engine start-up, the engine being equipped with a radiator and a water jacket, the system comprising:

• a first flow control valve for controlling flow of a temperature control fluid through a passageway between the water jacket and the radiator, the first flow control valve having a first state for preventing said flow and a second state for allowing said flow, the valve being in the first state during warm-up or start-up;
• a first sensor for measuring actual engine operation temperature indicative of engine oil temperature;
• means for comparing the measured engine operation temperature to a preselected engine operation temperature;
• an engine computer for producing control signals and sending said control signals to the flow control valve to control the state of the valve, the engine computer maintaining the valve in the first state until the actual engine operation temperature reaches the preselected engine operation temperature, regardless of the temperature of the temperature control fluid, the engine computer placing the valve in the second state when the actual engine operation temperature reaches the preselected engine operation temperature;
• a second sensor for measuring ambient air temperature;
• and
• means for storing a plurality of optimum engine operation temperatures each having a corresponding ambient air temperature value and for outputting the optimum engine operation temperature for the measured ambient air temperature, wherein the preselected engine operation temperature is the optimum engine operation temperature at the current measured ambient air temperature.

A method for controlling the state of a flow control valve in an internal combustion engine during engine warm-up or engine start-up, the engine being equipped with a radiator and a water jacket, the flow control valve controlling flow of temperature control fluid between the water jacket and the radiator, the valve being in a closed state upon warm-up or start-up, thereby preventing flow of the temperature control fluid, the method comprising the steps of:

• (a) measuring an actual engine operation temperature indicative of engine oil temperature with a first temperature sensor;
• (b) comparing an actual engine operation temperature to a preselected engine operation temperature;
• and
• (c) maintaining the valve in the closed state until the actual engine operation temperature reaches the preselected engine operation temperature, regardless of the temperature of the temperature control fluid, the engine computer placing the valve in the second state when the actual engine operation temperature reaches the preselected engine operation temperature.

A temperature control system in a liquid cooled internal combustion engine equipped with a radiator and a water jacket, the system comprising:

• a first flow control valve for controlling flow of a temperature control fluid through the water jacket, the first flow control valve having a first state for inhibiting said flow and a second state for allowing said flow;
• a first sensor for measuring an actual engine operation temperature indicative of engine oil temperature and for providing a signal indicative thereof;
• a second sensor for measuring actual ambient temperature and for providing a signal indicative thereof;
• means responsive to said actual ambient temperature signal for determining a desired engine operation temperature based on said actual ambient temperature, said desired engine operation temperature varying as a function of ambient temperature;
• means for comparing said actual engine operation temperature to said desired engine operation temperature;
• and
• means for controlling the state of the flow control valve between said first and second states, said flow control valve being in said first state when said actual engine operation temperature is less than said desired engine operation temperature and said flow control valve being in said second state when said actual engine operation temperature exceeds said desired engine operation temperature.

A temperature control system in a liquid cooled internal combustion engine equipped with a radiator and a first water jacket associated with a cylinder head and a second water jacket associated with a intake manifold, the system comprising:

• a first flow control valve for controlling flow of a temperature control fluid from the first water jacket to the second water jacket, the first flow control valve having a first state for inhibiting said flow and a second state for allowing said flow;
• a first sensor for measuring an actual engine operation temperature indicative of engine oil temperature and for providing a signal indicative thereof;
• a second sensor for measuring actual ambient temperature and for providing a signal indicative thereof;
• means responsive to said actual ambient temperature signal for determining a desired engine operation temperature based on said actual ambient temperature, said desired engine operation temperature varying as a function of said actual ambient temperature;
• means for comparing said actual engine operation temperature to said desired engine operation temperature;
• and
• means for controlling the state of the flow control valve between said first and second states, said flow control valve being in said first state when said actual operation temperature is less than said desired operation temperature and said flow control valve being in said second state when said actual operation temperature exceeds said desired operation temperature.

A method for controlling the state of a flow control valve in an internal combustion engine equipped with a radiator, an engine block and an oil pan, the flow control valve controlling flow of temperature control fluid, the method comprising the steps of:

• (a) measuring a first temperature which is indicative of the actual engine oil temperature;
• (b) measuring an ambient air temperature;
• (c) determining a threshold engine temperature value for the sensed ambient temperature, said threshold engine temperature value varying as a function of the ambient air temperature;
• (d) comparing said first temperature with the threshold engine temperature value to determine a desired valve position;
• (e) actuating the valve so as to place it in said desired valve position.

A method for controlling the flow of temperature control fluid in an internal combustion engine equipped with a radiator, a water jacket in an engine block, a water jacket in a cylinder head and a water jacket in an oil pan, the method comprising the steps of:

• (a) measuring a first temperature which is indicative of the actual engine oil temperature;
• (b) measuring an ambient air temperature;
• (c) determining a threshold engine temperature value for said sensed ambient temperature, said threshold engine temperature value varying as a function of said ambient air temperature;
• (d) comparing said first temperature with the threshold engine temperature value;
• (e) enabling flow of the temperature control fluid through the cylinder head water jacket and the oil pan water jacket and preventing flow through the radiator when the first temperature is less than the threshold engine temperature value, whereby heat from the cylinder head is transferred to oil pan by the temperature control fluid;
• and
• (f) permitting flow of the temperature control fluid through the engine block water jacket and the cylinder head water jacket when the first temperature is greater than the threshold engine temperature value.