Apparatus for internal combustion engine

Apparatus for improving the operation of a water-cooled internal combustion engine system which may include at least an internal combustion water-cooled engine, a radiator with interconnecting supply and return passageways, a water circulating pump means and means to regulate the temperature of the water; said apparatus enabling selectably controlling the cooling water temperature regulation, said improved operation including at least improved fuel economy, increased power output and/or increased heat output of a vehicle's interior heater.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 This invention discloses the application of new apparatus to enable
 improving the operation of an internal combustion engine system by
 selectably controlling the temperature of the cooling water in the engine.
 Conventional practice in achieving water cooling for internal combustion
 engines is to arrange an external radiator with supply and return
 connections and hoses for appropriate connection to the engine, the
 cooling water medium being circulated through the engine to the external
 radiator and back by means of a water pump. It is typical in such cooling
 systems that a thermostatic flow control valve be provided in the water
 flow path to enable the engine to achieve normal operating temperature
 quickly, but also to maintain a substantially steady state temperature
 according to a pre-arranged temperature set point setting, regardless of
 variable conditions imposed on the engine. Typically, thermostat settings
 used in internal combustion engine applications are chosen in the range of
 160 deg. F. to 195 deg. F. Such thermostats typically have a
 non-adjustable set-point and the thermostats are only removed and replaced
 infrequently in response to failure. In such cases they are typically
 replaced by a thermostat of a similar set-point temperature in accordance
 with the original manufacturer's specifications.
 It has been known for individual automobile and light truck operators to
 substitute thermostats of different temperature set points for summer
 versus winter operation, believing that there will be less risk of engine
 and transmission overheating if, for example a 160 deg. F. thermostat is
 used in summer, but that the interior heater will be more effective if a
 higher temperature thermostat, for example 195 deg. F., is substituted for
 winter use. The inventor also notes that the radiator cooling system
 performs at least the auxilliary function of cooling the oil of a
 vehicle's automatic transmission and that it would similarly benefit from
 the seasonal changing of low and high temperature thermostats. This
 seasonal changeover is problematic, however, in that it requires
 considerable manual effort for removal and exchanging the summer and
 winter thermostats to accommodate the changing of the seasons.
 The inventor has observed that light vehicles manufactured in North America
 may be equipped from the factory with a higher thermostat set-point of,
 for example, 195 deg. F., whereas light vehicles from Japan may be
 equipped from the factory with a lower thermostat set-point of, for
 example, 160 deg. F. This inventor has observed, however, that vehicles
 provided with the higher temperature set-point may suffer from poor
 performance in summer, and those provided with the lower thermostat set
 point may suffer from poor interior heater output under, for example,
 winter conditions.
 The practical difficulty of changing an engine's water temperature
 set-point in response to or in anticipation of any particular operating
 condition or environment imposed upon or anticipated for the engine may
 also be seen as an impediment to vehicle manufacturers in seeking to fully
 optimize the operating conditions of the internal combustion engine. It is
 known by performance enthusiasts, for example, that torque and power
 output of an engine can be maximized by running the engine under "cooler"
 water temperature conditions. Also, at least some researchers have
 recognized that engine knocking is affected by the temperature of the
 engine's cooling water. It is therefore clear that efforts to optimize
 this engine operating condition have been hampered by the lack of a simple
 and practical method of providing a selectable set-point for the internal
 water temperature condition of the internal combustion engine.
 For these reasons a primary objective of this invention is to provide
 apparatus enabling the selection of one or the other of a higher or lower
 temperature setpoint from, for example, a relatively "high" set point
 temperature of 195 deg. F. to a relatively "low" 160 deg. F. in a typical
 automotive internal combustion engine, without substantial manual effort
 or disassembly of components of the engine system. Another objective is to
 provide suitable apparatus to enable a simple retrofitting of existing
 vehicles with enabling apparatus. Other objectives are to construct such
 apparatus as utilizing ordinary, inexpensive and readily available
 thermostatic control valve elements and to avoid complex or costly or
 bulky additional componentry to be added to the engine system.
 2. Description of the Related Art
 One avenue of providing apparatus capable of varying the water temperature
 set-point in an internal combustion engine was disclosed in U.S. Pat. No.
 5,390,632 by Ikebe et al. in which were arranged multiple temperature and
 air pressure sensors, engine speed sensor and a knocking detector in a
 system to provide inputs to a computer; the computer being programmed to
 make certain decisions in response to the inputs, such decisions resulting
 in, for example, the variable operation of a water flow control valve, a
 cooling fan and a variable speed water pump. This system is obviously
 complex, expensive, subject to maintenance attention and unsuitable for
 retrofit application to vehicles already in service. Other novel cooling
 system apparatus described in known prior art is similarly more complex
 and less practical to apply to new or existing internal combustion engines
 than the present invention.
 BRIEF SUMMARY OF THE INVENTION
 The cooling system apparatus of this disclosure achieves at least two
 different operating set point temperatures for an internal combustion
 engine by arranging two conventional thermostats of differing set point
 temperatures series-wise into the cooling water flow path leading from the
 engine to the radiator and enabling manual or other selection of which of
 the two thermostats controls flow in the cooling water flow path.

DETAILED DESCRIPTION OF THE INVENTION
 FIG. 1 is a schematic representation of measuring and display means for
 fuel economy in a vehicle, in which a speed sensor 1 detects the rotation
 of a wheel 2, a sensor 3 detects the rate of fuel delivery in a fuel
 delivery line 4 to an engine 5. Sensor inputs to a computer 6 are
 processed with fuel consumption rate per distance results being displayed
 on a dash-mounted monitor 7. Fuel economy read-outs of this kind are
 commonly known in automobiles of the 80's and 90's, in which on-board
 computers and monitors have been programmed to display travel distances,
 fuel remaining in the tank, fuel economy and other parameters and vehicle
 diagnostics. With respect to the present invention, the fuel economy
 read-out provides useful information to the operator about the performance
 of the vehicle. In particular, the operator could see the effects upon
 fuel economy by the operation of the vehicle under a first selectable
 cooling water temperature condition, versus at least a second selectable
 water temperature condition as under the present invention.
 FIG. 2 illustrates a typical cooling system schematic diagram for an
 internal combustion engine, in which water cooling in a radiator 8 is
 assisted by a fan 9, has a cooled water passageway 10 connecting to an
 internal combustion engine 11, which has a water pump 12 and a
 conventional thermostatic flow control valve 13 mounted in or in close
 proximity to the engine, and a heated water passageway 14 leading back to
 the radiator 8. The cooled water passageway 10 and the heated water
 passageway 14 refer to radiator outlet and inlet water flow paths
 respectively, connecting to engine inlet and outlet connections
 respectively, and may typically be formed of reinforced rubber hoses of
 from 1" to 2" internal diameter. Thermostat 13 is only operable at a
 single set-point temperature typically chosen in the range of 160 deg. F.
 to 195 deg. F. depending upon the manufacturer's specification. Other
 components of a typical cooling system such as the pressure-release
 radiator cap, the interior heater, the transmission oil cooling provisions
 and the internal water flow passageways of the engine and other
 miscellaneous features known to comprise internal combustion engines and
 their cooling systems are omitted from the schematic diagram for
 simplicity. As well, the driving arrangement of the radiator's cooling fan
 and the water pump are omitted from the schematic.
 In operation, the thermostatic flow control valve 13 initially remains
 closed while the engine warms up. At its pre-set operating temperature the
 valve begins to open and will have fully opened over a small additional
 temperature rise of typically 10 to 20 deg. F. Variable loading of the
 engine imposes variable heat dissipation duty on the cooling system, which
 responds by appropriately increasing or decreasing the water flow rate by
 means of variable opening of the temperature-responsive thermostatic flow
 control valve 13 within its operating temperature range. The temperature
 set-point of a typical engine thermostat is not adjustable, however. Also,
 access to the thermostat for inspection and/or replacement involves at
 least partial draining of the radiator/engine coolant and nominal engine
 disassembly and subsequent reassembly.
 FIG. 3 illustrates a schematic representation of enabling apparatus for the
 present invention. In comparison to FIG. 3, an additional thermostat 15 is
 mounted in a suitably adapted housing 16 in the heated water flow
 passageway 14, such that heated water must flow past the initial
 thermostat 13 and the additional thermostat 15 in order to reach the
 radiator 8, eventually returning into the cooled water passageway 10 and
 the engine 11. In this case, thermostat 13 is selected to have a "low"
 temperature set-point of, for example 160 deg. F. while the additional
 thermostat 15 is selected to have a "high" temperature set-point of, for
 example 195 deg. F. There is also provided a low-flow heated water by-pass
 passageway 17 at the additional thermostat 15, which passageway always
 remains open.
 Thermostat 15 is provided with an external operator or handle 18 such that
 operation of the handle 18 places the thermostat into a first "closed"
 position or a second "opened" position, as evidenced by the position of
 the external handle. In the first closed position, heated water must pass
 through the thermostat, meaning the water temperature must reach at least
 the "high" set point before any substantial water flow can be achieved in
 the heated water flow passageway 14 to the external radiator. In the
 second open position of the handle, however, water flow in the heated
 water passageway 14 can bypass the additional thermostat 15. Water flow
 through the cooling system in this case will be established as soon as the
 water temperature meets or exceeds the "low" temperature set-point of the
 initial thermostat 13.
 It is clear, therefore, that operation of the cooling system with handle 18
 in the first closed position will result in a nominal cooling water
 temperature of 195 deg. F. being maintained due to the operation of the
 additional thermostat 15, whereas operation of the cooling system with the
 handle 18 in the second open position will result in a nominal cooling
 water temperature of 160 deg. F. being maintained by the operation of the
 initial thermostat 13 and by-passing of the additional thermostat 15. It
 is also dear that the initial thermostat 13 opens fully in the first case,
 thereby having no controlling effect upon the cooling system water flow
 rate and/or temperature. The additional thermostat 15 is effectively
 by-passed in the second case for the open position of the handle 18,
 therefore it has no controlling effect upon cooling water flow rate and/or
 temperature in such a case.
 Low-flow by-pass passageway 17 is beneficial in the first case of the
 selectable by-pass at additional thermostat 15 being closed, said low-flow
 bypass maintaining a nominal flow of heated water in flow passageway 14
 after initial thermostat 13 opens, said nominal flow being adequately
 provided at about 10% of the unrestricted full flow rate such that heated
 water continually reaches the active temperature sensing element of
 additional thermostat 15 without significant cooling. In order to be
 responsive to the actual engine operating temperature, additional
 thermostat 15 is preferably installed in heated passageway 14 in
 relatively close proximity to initial thermostat 13.
 It should be noted that the order of placement of the low temperature
 thermostat 13 and the high temperature thermostat 15 is irrelevant to the
 working of the said enabling apparatus, providing that the selectable
 by-pass means must be associated with the higher temperature thermostat,
 and the by-pass passageway 17 must be associated with the second
 series-wise thermostat. For greater clarity, thermostat 15 in FIG. 3 is in
 the second series-wise position with respect to thermostat 13 when
 considering the water flow direction in heated water passageway 14.
 FIG. 4 illustrates a preferred embodiment of additional thermostat 15 of
 FIG. 4 in which a conventional thermostatic flow control valve element 19
 is positioned and held in clamped relationship at its circular flange 20
 between two cylindrical housing components 21 and 22 of a valve assembly,
 said housing components being assembled and retained together at male
 screw thread 23 on component 21 engaging with female thread 24 on housing
 component 22. Housing component 21 is arranged with one or more radial
 slots 25 providing fluid communication between internal water inlet
 passageway 26 and an external annular chamber 27 Housing component 22 is
 similarly arranged with one or more radial slots 28 providing fluid
 communication between external annular chamber 27 and internal water
 outlet passageway 29. An easily obtained design objective for the fluid
 passageways is that the cross-sectional flow areas be large enough as to
 provide little cooling water flow resistance when installed in the
 passageway of an internal combustion engine's water cooling system.
 In the figures, external handle or operator 18 of FIG. 3 corresponds to
 externally operable cylindrical slide valve 30 in FIGS. 4 and 5, which is
 arranged with internal cylindrical land areas 31, closely enveloping
 cooperating cylindrical surfaces of housing component 21. Slide 30 is
 operable in the longitudinal direction such as between a first "open"
 position as in FIG. 4 allowing cooling water to by-pass the thermostatic
 valve element 19 freely, versus a second "closed" position as in FIG. 5 in
 which the fluid bypass path is effectively blocked. Detent means (not
 shown) are conveniently arranged between slide valve 30 and housing
 component 21 to retain valve 30 in either one of its open or closed
 positions. O-ring seals 32 and 33 in housing components 21 and 22,
 respectively, are arranged to form fluid seals between slide valve 30 and
 housing components 21 and 22, preventing fluid from leaking from the
 internal regions of the apparatus. Nominal internal fluid leakage paths
 past land areas 31 are provided via controlling the clearances at the land
 areas 31 between slide component 30 and housing component 21 such as to
 satisfy the required leakage flow path function of passageway 17 in FIG.
 3.
 A preferred installation of additional thermostat 15 in heated water
 passageway 14 in typical vehicle applications involves cutting rubber hose
 14 circumferentially, thus enabling housing components 21 and 22 to be
 snugly inserted into the cut hose ends, which are then secured and sealed
 with hose clamps or the like. After installation, slide component 30
 remains exposed and accessible to enable the operator of the vehicle to
 selectably move the slide between its open and its closed positions.
 Clearly, the flow of cooling water in heated passageway 14 (and therefore
 its temperature) is unaffected by the presence of thermostatic valve
 element 19 when slide 30 is positioned to enable fluid to by-pass the
 thermostat. When slide 30 is positioned to close the by-pass passageway,
 cooling water flow is prevented until the water temperature increases to
 the set point temperature of thermostatic valve element 19, following
 which a continuous flow of cooling water circulates through the external
 radiator and the cooled water passageway back to the engine again, said
 flow being continuously regulated to maintain temperature agreement with
 the set point of thermostatic valve 19.
 Although only two steps of temperature regulation have been described for
 enabling apparatus for the method of the invention, it will be obvious
 that any desired number of temperature steps could be achieved by
 employing additional series-wise thermostats mounted individually and
 provided with operators to achieve open and closed positions, each also
 incorporating a functional water flow by-pass passageway 17.
 The inventor has therefore disclosed a simple method and apparatus for
 enabling selectable control of the cooling water temperature of an
 internal combustion engine. Clearly, an operator can easily move slide
 valve 30 to its open position, thus causing the engine's cooling water
 temperature to be controlled by the 160 deg. F. thermostat for improved
 fuel economy and/or operation under an anticipated high-load condition.
 Alternatively, the operator can move slide valve 30 to its closed
 position, thus improving the interior heater output in winter conditions
 in a vehicle application. If the vehicle is equipped with on-board fuel
 economy measuring/displaying hardware, the operator will be able to
 confirm that for the given loading conditions and ambient temperatures, he
 has selected the appropriate open or closed position of slide 30.
 Whereas the embodiments already noted imply manual selection of the open
 and closed positions for additional thermostat 15, other embodiments will
 be obvious to those skilled in the art. For example, the inventor notes
 that any powered actuation means which could be used to operate a slide 30
 of a by-pass assembly or mechanism constructed in conjunction with
 additional thermostat 15, would also enable selectable temperature control
 for the internal combustion engine.
 Further, the inventor notes that any automatic means of detection of
 conditions leading to a decision to select the opposite of an existing
 open or closed position of by-passing an additional thermostat 15, and
 causing the selection of that opposite position by manual or automatic
 means, would constitute enabling apparatus for the method of the
 invention.
 The inventor notes that although the term "water" appears throughout the
 disclosure of this invention, in fact, typical internal combustion
 engine's cooling systems are filled with a mixture of water and
 anti-freeze including special compounds to combat corrosion or for other
 purposes. The inventor respectfully requests that the reader will accept
 this broader definition of the term "water" when used in the sense of the
 cooling medium for an internal combustion engine throughout this
 disclosure.