# US 7,464,699 B2 · Control of an electrically heated pre-heating device for cold-starting internal combustion engines > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,464,699 B2 - Document ID: US7464699B2 - Status: Granted - Kind: B2 - Application number: 10/564,952 - Filed: 2004-07-15 - Published: 2007-03-22 - Granted: 2008-12-16 - Earliest claimed: 2003-07-19 - Assignees: Daimler AG - Inventors: Peter Joppig; Frank Lantermann; Friedrich Schmid; Karl-Heinz Vogel - Web page: https://patentgrep.com/patent/US7464699B2 ## CPC - F02M 31/13: Combustion air - F02D 9/10: having pivotally-mounted flaps - F02M 31/135: Fuel-air mixture - Y02T 10/12: Improving ICE efficiencies - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract In a method for heating up the intake air of an internal combustion engine during the preglow phase or start-up phase, the heating power is controlled by a control unit of the engine electronics as a function of the operating data of the internal combustion engine. During the preglow phase, the heating element is initially supplied with full current until the heating element reaches its reference temperature. After the reference temperature has been reached and until the start-up phase, a post-heating phase begins in which the heating element is kept at a constant temperature by way of a relatively low power. During the start-up phase, in a first time period, the heating element is switched off, and in a second time period in which the speed of the internal combustion engine is raised to the starting speed, the heating element is switched on again. ## Claims ### Claim 1 A method for heating up the intake air of an internal combustion engine during a preglow phase or a start-up phase with at least one electrically heatable heating element in an intake line of the internal combustion engine, heating power being controlled by a control unit as a function of operating data of the internal combustion engine, comprising: supplying the heating element with full current during the preglow phase until the heating element reaches its reference temperature, beginning a post-heating phase, in which the heating element is kept at a constant temperature by a relatively low power, after the reference temperature has been reached and until the start-up phase, switching the heating element off in a first time period during the start-up phase, and switching the heating element on again in a second time period during the start-up phase in which the speed of the internal combustion engine is raised to the starting speed. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein a start-readiness phase, in which the heating element is operated at a further reduced power, follows the post-heating phase. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein, in a subsequent afterglow phase, an afterglow at a reduced heating power is carried out after the idling speed has been reached and until an applicable engine temperature is raised. ### Claim 4 (depends on 3) The method as claimed in claim 3, wherein, in the afterglow phase, the charge air temperature is kept constant by way of the heating element during an increase in speed. ### Claim 5 (depends on 3) The method as claimed in claim 3, wherein an afterglow period is determined at the beginning of the start process as a function of the coolant temperature or the charge air temperature. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the heating element is switched off in a timed or temperature-controlled manner. ### Claim 7 (depends on 2) The method as claimed in claim 2, wherein, in a subsequent afterglow phase, an afterglow at a reduced heating power is carried out after the idling speed has been reached and until an applicable engine temperature is raised. ### Claim 8 (depends on 7) The method as claimed in claim 7, wherein, in the afterglow phase, the charge air temperature is kept constant by way of the heating element during an increase in speed. ### Claim 9 (depends on 7) The method as claimed in claim 7, wherein an afterglow period is determined at the beginning of the start process as a function of the coolant temperature or the charge air temperature. ### Claim 10 (depends on 2) The method as claimed in claim 2, wherein the heating element is switched off in a timed or temperature-controlled manner. ### Claim 11 (depends on 3) The method as claimed in claim 3, wherein the heating element is switched off in a timed or temperature-controlled manner. ### Claim 12 (depends on 4) The method as claimed in claim 4, wherein the heating element is switched off in a timed or temperature-controlled manner. ### Claim 13 (depends on 5) The method as claimed in claim 5, wherein the heating element is switched off in a timed or temperature-controlled manner. ### Claim 14 (depends on 2) The method as claimed in claim 2, wherein an afterglow period is determined at the beginning of the start process as a function of the coolant temperature or the charge air temperature. ### Claim 15 (depends on 4) The method as claimed in claim 4, wherein an afterglow period is determined at the beginning of the start process as a function of the coolant temperature or the charge air temperature.