Gm Global Technolgoy Operations, Inc.

Angelo Argento

Stefano Nieddu

Paolo Casasso

Filippo Parisi

Stefano Cassani

Andrei Gheorghi Kanev

Tiziana Belvedere

Methods and apparatus are provided for a high current control strategy and a low current control strategy using fixed threshold values and variable threshold values. An electrical quantity related to an electrical current which is to be switched is received on an input. The electrical quantity related to the electrical current is compared with a predefined first fixed threshold value in a first comparator for determining a first logical state. The electrical quantity is compared with a first variable threshold value in a second comparator for determining a second logical state. The electrical current is switched between an ON state and an OFF state in response to a switching signal on an output terminal when the electrical quantity of the electrical current meets the first variable threshold value. The first logical state, the second logical state and the switching signal provided at the output terminal vary the first variable threshold value.

Switching signal generating apparatus and method

A method is provided that includes, but is not limited to the steps of driving in an on-off manner in a period of time an electronic switch in series with a respective glow plug between the terminals of a d.c. voltage supply, sensing the glow plug voltage and the glow plug current, generating analogue sense signals representative of the time integral of the glow plug voltage and current, generating analogue reference signals corresponding to the digital values of corresponding control words, comparing the sense signals to the respective reference signals and modifying the corresponding control words so as to minimize the difference between the sense signals and the reference signals, calculating the average values of the sensed voltage and current on the basis of the values of the control words at the beginning and at the end of the 'on' time of the electronic switch.

Method and an apparatus for controlling glow plugs in a diesel engine, particularly for motor-vehicles

A method is provided for controlling a glow plug (GP) associated with a cylinder chamber of a Diesel engine. The method includes, but is not limited to the steps of driving in an on-off manner in a period of time an electronic switch (M) connected essentially in series with the glow plug (GP) between the terminals of a d.c. voltage supply (B), sensing the voltage (V) across the glow plug (GP) and the current (I) flowing through the glow plug (GP) and performing a voltage closed loop control for controlling the temperature of the glow plug (GP). The method further includes, but is not limited to the steps of calculating a normalized current error (&#x3b5;I) as a function of said sensed current (I), calculating a normalized voltage error (&#x3b5;V) as a function of said sensed voltage (V), calculating a weight function (K) as a function of predetermined parameters (&#x3b1;, &#x3b2;, n) and calculating a global error (&#x3b5;) as a function of said normalized current error (&#x3b5;I), normalized voltage error (&#x3b5;V) and weight function (K). Finally, the method includes, but is not limited to the step of combining the voltage closed loop control with a current closed loop control according to the value of said global error (&#x3b5;).

A glow plug control unit is provided that includes a first switch for connecting power supply lines to a glow plug. The glow plug control unit further includes a voltage measurement unit for measuring the voltage at the power supply lines. A current measurement unit is built for measuring the current through the first switch and a control circuit is built for controlling the first switch and, in a current control mode, for regulating the current through the first switch.

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Turin, Italy

Angelo Argento