Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P7/00—Controlling of coolant flow
  • F01P7/14—Controlling of coolant flow the coolant being liquid
  • F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
  • F01P7/167—Controlling of coolant flow the coolant being liquid by thermostatic control by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P7/00—Controlling of coolant flow
  • F01P7/14—Controlling of coolant flow the coolant being liquid
  • F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
  • F01P7/161—Controlling of coolant flow the coolant being liquid by thermostatic control by bypassing pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P7/00—Controlling of coolant flow
  • F01P7/14—Controlling of coolant flow the coolant being liquid
  • F01P2007/146—Controlling of coolant flow the coolant being liquid using valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P2025/00—Measuring
  • F01P2025/08—Temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P2025/00—Measuring
  • F01P2025/60—Operating parameters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P2025/00—Measuring
  • F01P2025/60—Operating parameters
  • F01P2025/62—Load
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P2060/00—Cooling circuits using auxiliaries
  • F01P2060/08—Cabin heater

Definitions

• the invention relates to a cooling for an internal combustion engine.
• a thermostat is provided to improve warm up time.
• the engine block is isolated by a thermostat from the radiator until a certain coolant temperature is reached and thereafter that temperature is maintained by heat rejection to the radiator.
• the present invention seeks to provide a coolant system in which heat retention in the immediate vicinity of the combustion chambers is maximised immediately after startup.
• an engine cooling system characterised by integrating means for generating a signal representing the total heat rejection from the combustion chamber following engine startup, and electrically operable valve means which are actuated to prevent all circulation of coolant through at least the cylinder head until the output signal of the integrating means attains a predetermined threshold.
• valve means are additionally operative to prevent coolant from circulating through the engine block.
• valve means may include a by-pass passage connected across the coolant pump, which by-pass passage is normally closed and is opened only during the said predetermined time.
• the integrating means may simply be a time integrator, the threshold being set to between zero and three minutes.
• the time must be selected to be the shortest period in which boiling can occur assuming high speed and high load. In practice, a much longer period could still prove safe. For this reason, it is preferred to use another parameter, other than the coolant temperature, to estimate the heat rejection from the engine.
• the total number of revolutions from startup may be integrated and the valve means reset after a certain number of turns of the crankshaft. This is an improvement over measuring time alone since this measure is no longer affected by changes in engine speed.
• the heat rejection during a fixed number of engine revolutions is still load dependent and to eliminate this source of error, the count may be weighted to allow for the load as sensed for example from the manifold vacuum or throttle pedal position.
• a preferred and more direct assessment of the total heat rejection after startup can be gained by integrating the total fuel flow or the total mass air flow.
• integration either of the output of the air flow meter or the pulses applied to the fuel injectors provides a signal directly related to the total heat rejection.
• the total heat which should be retained after startup depends upon the initial engine temperature, that is to say the temperature before startup. If the engine is already warm, then it may be unnecessary to retain any additional heat and if the engine is very cold, having for example been left inoperative for a long period in a cold ambient atmosphere, then an extended period may be safely be adopted to enable rapid warm up of the combustion chambers. It is therefore preferred to set the threshold in dependence upon the engine temperature before startup.
• FIG. 1 is a block diagram of a coolant system in accordance with the invention.
• Figure 2 is a block diagram of a circuit for controlling the isolation valve of a coolant system.
• the cooling system and the engine are entirely conventional. Below the opening temperature of the thermostat 22, no circulation takes place through the radiator 20 and the smaller volume of coolant trapped in the block 12 and the cylinder head 14 can heat up more rapidly.
• the present invention is aimed at preventing all circulation of coolant past the combustion chambers when the engine is cold and achieves its objective by the use of an electrical ⁇ ly controlled isolation valve 26 which is closed to ensure that there is no closed coolant circuit powered by the pump 24.
• the pump 24 can be prevented from operating during cold starts, or it can be allowed to cavitate during the short time that the valve 26 is closed.
• a by-pass valve 16 connected in shunt with the pump 24 and short circuits the inlet and outlet connections of the pump 24 to allow at least a small amount of circulation around the pump without the coolant needing to pass through the engine 10, in order to prevent cavitation.
• the valve 26 is opened and closed by an integrating circuit ( Figure 2) rather than in response to the sensing of a critical temperature.
• a sensing circuit 30 receives an input signal from the engine and its output is integrated by an integrating circuit 32.
• the output of the integrating circuit 32 is compared in a comparator 34 with a threshold set by a circuit 38 and if the set threshold is exceeded then the isolation valve 26 is opened to allow normal coolant circulation.
• the threshold setting circuit 38 in the illustrated embodiment also receives a signal from a temperature sensor 40 and sets the threshold in dependence upon the coolant temperature before starting.
• the output of the integrating circuit 32 is required to represent the total heat rejection from the engine following the starting of the engine.
• the integrating circuit 32 can integrate time pulses, engine cycles, the durations of fuelling pulses, or samples of analogue signals derived from the mass air flow meter of a fuel injection system, and the sensing circuit 30 is designed accordingly.
• Engine running time is a first approximation
• total engine cycles is a better second approximation because it is not engine speed dependent but the most useful reading is to be derived by measurement of the fuel or air used in the combustion process.
• the engine temperature is measured by the sensor 40 and the threshold setting circuit 38 provides a reference signal for the output of the integrating circuit which is inversely proportional to the difference between the measured starting temperature and the normal running temperature.
• the valves 16, 26 used to prevent circulation of the coolant past the combustion chamber are operated for as long as the output signal of the integrating circuit lies below the set reference threshold and thereafter the coolant is allowed to circulate normally.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=10681713

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (10)

Family Cites Families (5)

• 1990
  • 1990-09-05 GB GB9019391A patent/GB2247745A/en not_active Withdrawn
• 1991
  • 1991-09-04 DE DE69122968T patent/DE69122968T2/de not_active Expired - Fee Related
  • 1991-09-04 EP EP91916280A patent/EP0548174B1/de not_active Expired - Lifetime
  • 1991-09-04 WO PCT/GB1991/001500 patent/WO1992004534A1/en active IP Right Grant

Non-Patent Citations (1)

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