Electric heating device, particularly for a heating or air-conditioning unit in a vehicle

Abstract

Electric heating device comprising an electric radiator (10) for heating the air passing through it, said radiator comprising a casing (12), at least one resistive element mounted in the casing and constituted by at least one zigzag metal strip (22) which is disposed so as to be directly exposed to the air passing through the casing, and a circuit (30) for controlling the electrical supply of the resistive element or elements connected to a power supply. The electric radiator (10) comprises a set of individual heating modules (20) disposed parallel to one another in the casing (12) and so as to be directly exposed to the air passing through the casing, each heating module (20) comprising a pleated or corrugated metal strip (22) and an electronic switch controlled by the control circuit (30) intended to selectively inhibit the electrical supply of the metal strip (22).

Description

BACKGROUND OF THE INVENTION [0001] The invention concerns an electric heating device comprising an electric radiator passed through by the air to be heated and in particular passed through by at least part of an air flow produced by an air flow generator, such as a fan or blower. [0002] The field of application of the invention is more particularly that of heating and / or air-conditioning apparatuses for vehicles, in particular private and commercial motor vehicles and heavy lorries. [0003] Usually, the heating up of the air intended for heating the passenger compartment of a motor vehicle, and for demisting and defrosting, is provided by passing a flow of air through a heat exchanger through which the engine block cooling liquid runs. [0004] This heating method may prove unsuitable or insufficient in a number of situations such as: [0005] preconditioning before starting the engine in order to provide heating up of the passenger compartment, and defrosting or demisting, in a remote o...

AI Technical Summary

Benefits of technology

[0012] Another aim of the present invention is to limit the number of components of the radiator, thus facilitating its mounting and reducing the manufacturing costs.

[0023] The electronic switch is integrated onto the metal connection support through tracks formed by said metal support and flanges are formed in the metal support facilitating the heat dissipation of the electronic switch by the air passing through the heating module.

[0030] The control circuit can comprise means of varying the power supplied by the radiator by modulating the supply voltage delivered to each heating module, for example by the pulse width modulation technique, which makes it possible to vary the power continuously or almost continuously.

[0038] Each metal strip has a profile chosen from amongst a sinusoidal profile, a triangular profile, a rectangular profile and a trapezoidal profile. According to a preferred embodiment, the heating device also comprises an air flow generator, characterised in that the electrical switches driven by the control circuit inhibit the electrical supply of the heating modules when the air flow rate passing through the radiator is below a minimum value, in order to provide protection against excessive heating.

Problems solved by technology

This heating method may prove unsuitable or insufficient in a number of situations such as: preconditioning before starting the engine in order to provide heating up of the passenger compartment, and defrosting or demisting, in a remote or pre-programmed manner, before use of the vehicle in a very cold environment, desired very fast rise in temperature in the passenger compartment, inability of the heat exchanger to supply the calories necessary for satisfactory heating up of the air in order to provide the heating functions and possible defrosting and demisting functions, as occurs during a certain time after starting, with certain types of engine with low heat loss.

The additional PTC resistor electric radiators work satisfactorily but have the drawback of having a high production cost owing to the cost of the PTC resistors, the number of constituent components, the necessary assembly time and the sensitivity to corrosion of the supply electrodes of the PTC resistors.

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