Abstract: A glow plug comprising: a cylindrical housing; a heater member as defined herein; a conductive center pole as defined herein; a first piezoelectric element as defined herein; and a second piezoelectric element as defined herein, wherein each of said first piezoelectric element and said second piezoelectric element is subjected to a preload for compressing it in said axial direction and is arranged such that, when said center pole is displaced to a root-end side, a load to be applied to one of said first piezoelectric element and said second piezoelectric element for compressing the same in said axial direction increases whereas a load to be applied to the other for compressing the same in said axial direction decreases.

Abstract: To provide a combustion pressure sensor capable of reducing noises generated by the force in a rocking direction by making uniform the stress exerted onto the piezoelectric element; and a glow plug having the same.

Abstract: A glow plug comprising: a cylindrical housing; a heater member as defined herein; a conductive center pole as defined herein; a first piezoelectric element as defined herein; and a second piezoelectric element as defined herein, wherein each of said first piezoelectric element and said second piezoelectric element is subjected to a preload for compressing it in said axial direction and is arranged such that, when said center pole is displaced to a root-end side, a load to be applied to one of said first piezoelectric element and said second piezoelectric element for compressing the same in said axial direction increases whereas a load to be applied to the other for compressing the same in said axial direction decreases.

Abstract: A misfiring detection apparatus including a comparison unit 22 and a time counting unit 24 which accumulates periods of time during which the ion current flowing between the center electrode 10a and the ground electrode 10b of a spark plug 10 exceeds a predetermined current value; and an ECU 26 which judges that misfiring has occurred when a total of the accumulated periods is not greater than a predetermined value. The ion current is thus determined as a cumulative value of ion current generation periods. Therefore, even when the ion current contains a discharge noise component, the discharge noise component having a short duration accounts for only a small portion of the cumulative value, so that the influence of the discharge noise component on misfiring detection can be reduced. As a result, misfiring detection can be performed with improved accuracy.

Abstract: A method of detecting spark plug fouling in an internal combustion engine is provided. The method comprises calculating an integration value of discharge current flowing between electrodes of a spark plug during a period of a spark discharge and judging if the calculated discharge current integration value is smaller than an integration value criterion. The integration value criterion is set at such a value that can discriminate between normal discharge and interior jumping (i.e., jumping due to short circuit caused by fouling). When the calculated discharge current integration value is smaller than the integration value criterion, it is judged that the spark plug has been fouled. By this, it becomes possible to detect a spark plug fouling before the electrodes of the spark plug are short-circuited and disabled to generate spark discharge, i.e., before the spark plug is fouled to such an extent as to cause a misfire. An ignition system for detecting spark plug fouling is also provided.

Abstract: A control system for an internal combustion engine is provided which comprises detecting means for detecting a discharge current flowing between electrodes of a spark plug when a high voltage for ignition is applied to the spark plug, judging means for judging whether or not the spark plug is fouled on the basis of the discharge current, and inhibiting means for inhibiting the progress of spark plug fouling when the spark plug is judged fouled. A method carried out by the control system is also provided.

Abstract: A misfiring detection apparatus including a comparison unit 22 and a time counting unit 24 which accumulates periods of time during which the ion current flowing between the center electrode 10a and the ground electrode 10b of a spark plug 10 exceeds a predetermined current value; and an ECU 26 which judges that misfiring has occurred when a total of the accumulated periods is not greater than a predetermined value. The ion current is thus determined as a cumulative value of ion current generation periods. Therefore, even when the ion current contains a discharge noise component, the discharge noise component having a short duration accounts for only a small portion of the cumulative value, so that the influence of the discharge noise component on misfiring detection can be reduced. As a result, misfiring detection can be performed with improved accuracy.

Abstract: A control system for an internal combustion engine is provided which comprises detecting means for detecting a discharge current flowing between electrodes of a spark plug when a high voltage for ignition is applied to the spark plug, judging means for judging whether or not the spark plug is fouled on the basis of the discharge current, and inhibiting means for inhibiting the progress of spark plug fouling when the spark plug is judged fouled. A method carried out by the control system is also provided.

Abstract: A low temperature energy carrying apparatus and method adapted for central cooling which comprises a hydrate circulating system for a liquid hydrate agent and hydrate crystals incorporated with a conventionally designed water circulating system. In the hydrate circulating system, the hydrate crystals are feed to the users side together with cooled water and decomposed therein into hydrate agent and cooled water absorbing the latent heat of decomposition. Therefore, the temperature of the cooled water during transport thereof to the users side is stabilized and in addition to the sensible heat of the cooled water the latent heat of the hydrate crystals can be utilized in the users side, thereby improving cooling effect in the users side. Also, the hydrate circulating system is adapted to use a hydrate agent in the liquid phase area which allows the operation of the system to be stabilized.