Dual mode windshield heater control

A dual mode method of operating a windshield heater element in an automotive vehicle having a transmission operable between park, neutral and one or more drive states, the method comprising the steps of:

• initiating a deice mode of operation in which the heater element is energized with maximum voltage to develop maximum heat effective to remove ice and frost from the exterior surface of the windshield in response to an operator actuated input when the transmission is in the park or neutral state;
• terminating the deice mode of operation in response to the first to occur of (a) expiration of a predetermined time period after initiation, or (b) an operator actuated input, or (c) shifting of the transmission to other than the park or neutral state;
• initiating a defog mode of operation in which the heater element is energized with reduced voltage to develop reduce heat effective to remove condensation from the interior surface of the windshield or to help prevent the formation of ice and frost on the exterior surface of the windshield in response to (a) an operator actuated input when the transmission is in other than the park or neutral state, or (b) termination of a preceding deice mode of operation provided that such termination was not in response to an operator actuated input;
• and
• terminating the defog mode of operation in response to the first to occur of (a) the expiration of a predetermined time period after initiation provided that such initiation was not in response to an operator actuated input, or (b) an operator actuated input.

A dual method of operating a windshield heater element in an automotive vehicle having a transmission operable between park, neutral and one or more drive states, and having a generator driven by the vehicle engine for providing electrical power to charge the vehicle battery and to energize the heater element with a load current, where the magnitude of the electrical power is dependent upon the idle speed of the engine when the transmission is in the park or neutral state, the method comprising the steps of:

• initiating a deice mode of operation in which the heater element is energized at maximum power to produce maximum heat effective to remove ice and frost from the exterior surface of the windshield in response to an operator actuated deice command provided that the transmission is in the park or neutral state so that the vehicle engine is operating at idle;
• terminating the deice mode of operation in response to the first to occur of (a) expiration of a predetermined time period after initiation, (b) shifting of the transmission to other than the park or neutral state, or (c) an operator actuated off command;
• initiating a defog mode of operation in which the heater element is energized at reduced power to produce reduced heat effective to remove condensation from the interior surface of the windshield or to help prevent the formation of ice and frost on the exterior surface of the windshield in response to (a) an operator actuated defog command, or (b) termination of a preceding deice mode of operation provided that such termination was not in response to an operator actuated off command;
• terminating the defog mode of operation in response to the first to occur of (a) expiration of a predetermined time period after initiation provided that such initiation was not in response to an operator actuated defog command, or (b) an operator actuated off command;
• and
• increasing the idle speed of the engine above the normal idle speed in response to initiation of the deice mode of operation to ensure adequate power output from the engine driven generator during such maximum power deice mode of operation.

A dual mode method of operating a windshield heater element in an automotive vehicle having a transmission operable between park, neutral and one or more drive states, and having a generator driven by the vehicle engine for providing electrical power to charge the vehicle battery and to energize the heater element with a load current, where the magnitude of the electrical power is dependent upon the idle speed of the engine when the transmission is in the park or neutral state, the method comprising the steps of:

• initiating a timed cycle in response to an initial operator actuated input when the transmission is in the park or neutral state and terminating the timed cycle in response to a subsequent operator actuated input;
• the timed cycle including (unless earlier terminated) a high heat mode of operation which is initiated when the timed cycle is initiated and which is terminated in response to the first to occur of expiration of a predetermined time period after initiation, or shifting of the transmission to other than the park or neutral state;
• the timed cycle further including (unless earlier terminated) a reduced heat mode of operation which is initiated in response to termination of the high heat mode of operation and which is terminated a predetermined time period after initiation;
• and
• initiating a continuous cycle in response to an initial operator actuated input when the transmission is in other than the park or neutral state and terminating the continuous cycle in response to a subsequent operator actuated input;
• the continuous cycle consisting of a reduced heat mode of operation which is initiated when the continuous cycle is initiated and which is terminated when the continuous cycle is terminated.

A dual mode method of operating a windshield heater element in an automotive vehicle having a transmission operable between park, neutral and one or more drive states and having a single operator actuated input switch, the method comprising the steps of:

• initiating a timed cycle in response to an initial operator actuation of the single input switch when the transmission is in the park or neutral state and terminating the timed cycle in response to a subsequent operator actuation of the input switch;
• the timed cycle including (unless earlier terminated) a high heat deice mode of operation effective to remove ice and frost from the exterior surface of the windshield where such deice mode of operation is initiated when the timed cycle is initiated and is terminated in response to the first to occur of expiration of a predetermined time period after initiation, or shifting of the transmission to other than the park or neutral state;
• the timed cycle further including (unless earlier terminated) a low heat defog mode of operation effective to remove condensation from the interior surface of the windshield or to help prevent the formation of ice and frost on the exterior surface of the windshield where such defog mode of operation is initiated in response to termination of the high heat mode of operation and which is terminated at the expiration of a predetermined time period after initiation;
• and
• initiating a continuous cycle in response to an initial operator actuation of the single input switch when the transmission is in other than the park or neutral state and terminating the continuous cycle in response to a subsequent operator actuation of the input switch:
• the continuous cycle consisting of a low heat defog mode of operation which is initiated when the continuous cycle is initiated and which is terminated when the continuous cycle is terminated.

A dual mode method of operating a windshield heater element in an automotive vehicle having a transmission operable between park, neutral and one or more drive states, and having a generator driven by the vehicle engine for providing electrical power to charge the vehicle battery and to energize the heater element with a load current, where the magnitude of the electrical power is dependent upon the idle speed of the engine when the transmission is in the park or neutral state, the method comprising the steps of:

• initiating a timed cycle in response to an initial operator actuated input when the transmission is in the park or neutral state and terminating the timed cycle in response to a subsequent operator actuated input;
• the timed cycle including (unless earlier terminated) a maximum power mode of operation which is initiated when the timed cycle is initiated and which is terminated in response to the first to occur of expiration of a predetermined time period after initiation, or shifting of the transmission to the park or neutral state;
• the timed cycle further including (unless earlier terminated) a reduced power mode of operation which is initiated in response to termination of the maximum power mode of operation and which is terminated a predetermined time period after initiation;
• initiating a continuous cycle in response to an initial operator actuated input when the transmission is in other than the park or neutral state and terminating the continuous cycle in response to a subsequent operator actuated input;
• the continuous cycle consisting of a reduced power mode of operation which is initiated when the continuous cycle is initiated and which is terminated when the continuous cycle is terminated;
• and
• increasing the idle speed of the engine above the normal idle speed in response to initiation of the maximum power mode of operation to ensure adequate power output from the engine driven generator during the maximum power mode of operation.