Intake air heating system for a vehicle

An air intake assembly includes heating elements. The heating elements include windings arranged in a serpentine configuration and having crest portions and trough portions. At least one crest portion of a first heating element is fastened to a corresponding trough portion of a second heating element. The heating elements are arranged in a honeycomb configuration.

FIELD

The present disclosure relates to intake air heating systems in internal combustion engines and more particularly to an air intake assembly having a heating coil and electronic control of intake air heating systems incorporating the air intake assembly.

BACKGROUND

An air-fuel mixture for an internal combustion engine is harder to ignite when cold, leading to less complete combustion and increased emissions. Once the engine has warmed up, the cylinders may warm the air-fuel mixture sufficiently. However, at startup, the engine may have no heat to contribute to the air-fuel mixture. Cold start conditions are especially severe when the ambient air temperature is low. An intake air heating system may be used to heat air arriving at the engine. This system may be located within or prior to the intake manifold. The intake air heating system may be brought up to temperature prior to attempting to start the engine.

Heating the intake air may allow for easier ignition and may hold the fuel in suspension more effectively, leading to fewer fuel droplets falling out of suspension in the air. Intake air heating systems may allow for faster starts of the engine, may reduce startup emissions, reduce engine wear, reduce overall battery consumption during startup, and reduce startup fuel consumption.

SUMMARY

An air intake assembly includes heating elements. The heating elements include windings arranged in a serpentine configuration and having crest portions and trough portions. At least one crest portion of a first heating element is fastened to a corresponding trough portion of a second heating element. The heating elements are arranged in a honeycomb configuration.

In other features, a length of the first heating element includes a length of the second heating element and a resistance of the first heating element includes a resistance of the second heating element. In other features, a length of the first heating element includes a range of between thirty centimeters to fifty centimeters. In other features, a thickness of the first heating element includes a thickness of the second heating element. In other features, the thickness of the first heating element includes a range between twenty thousandths of a centimeter to thirty thousandths of a centimeter. In other features, wherein a width of the first heating element includes a width of the second heating element.

In other features, crest portions of the first heating element are welded to corresponding trough portions of the second heating element to form interfaces. In other features, a length between a first interface and a second interface formed includes a length between the second interface and a third interface.

An air heater assembly includes a first heating element that includes windings arranged in a serpentine configuration and including crest portions and trough portions. The air heater assembly includes a second heating element including windings arranged in a serpentine configuration and including crest portions and trough portions. A crest portion of the second heating element is fastened to a trough portion of the first heating element. The air heater assembly includes a third heating element including windings arranged in a serpentine configuration and including crest portions and trough portions. A crest portion of the third heating element is fastened to a trough portion of the second heating element. The first heating element, the second heating element, and the third heating element are arranged in a honeycomb configuration.

In other features, a length of the first heating element includes a length of the second heating element and a length of the third heating element, and a resistance of the first heating element includes a resistance of the second heating element and a resistance of the third heating element. In other features, the length of the first heating element includes a range of between thirty centimeters to fifty centimeters.

In other features, a thickness of the first heating element includes a thickness of the second heating element and a thickness of the third heating element. In other features, the thickness of the first heating element includes a range between twenty thousandths of a centimeter to thirty thousandths of a centimeter.

In other features, a width of the first heating element includes a width of the second heating element and a width of the third heating element. In other features, the width of the first heating element includes a range between one centimeter and three centimeters.

In other features, the first heating element, the second heating element, and the third heating element include stainless steel.

An intake air heating system for a vehicle includes a heater coil that includes heating elements. The heating elements include windings arranged in a serpentine configuration and include crest portions and trough portions. A crest portion of a first heating element is fastened to a trough portion of a second heating element. The heating elements are arranged in a honeycomb configuration. The intake air heating system includes an air heater controller that is configured to selectively connect a battery of the vehicle to the heater coil in contact with intake air of the vehicle. The controller is configured to, in response to an enable signal from an engine controller, connect the battery to the heater coil to provide voltage to the heater coil and receive a resistance measurement indicative of a temperature of the heater coil. The controller is configured to, in response to the temperature of the heater coil exceeding or being equal to a predetermined temperature, adjust the voltage provided to the heater coil.

In other features, a crest portion of the first heating element is welded to a trough portion of a second heating element. In other features, a length of the first heating element includes a length of the second heating element, and a thickness of the first heating element includes a thickness of the second heating element. In other features, the length of the first heating element includes a range of between thirty centimeters to fifty centimeters, and the thickness includes a range between twenty thousandths of a centimeter to thirty thousandths of a centimeter.

DETAILED DESCRIPTION

Currently, air heaters take many seconds to heat to a temperature such that the heat generated by the air heater can sufficiently heat the intake air of an engine, such as a diesel engine. The present disclosure is directed to an air heater that includes relatively shorter heating elements arranged in a honeycomb structure to lower heat up time and provide a durable construction that mitigates damage to the heating elements from over-temperature or vibration. The air heater may also fill an air intake path, or throat, of the engine intake to minimize cold spots.

The present disclosure is also directed to an air heater controller that is able to determine the air heater temperature and control the current provided to the air heater to reach and maintain a desired operating temperature. In this way, even if the engine controller actuates the air heater system for longer than necessary, the air heater will not reach an over-temperature condition.

The air heater controller can receive signals from a temperature sensor representing a temperature of a heater coil employed within the air heater. The temperature sensor can measure a change in heater coil resistance, and the change in temperature can be used to determine a temperature of the heater coil. For example, change in heater coil resistance from a cold ambient starting temperature to operating temperature may be used to infer temperature and control the heating coil accordingly. Measuring resistance is generally performed by measuring voltage and current and calculating their ratio.

FIG. 1illustrates an intake air heating system100including selected ground and power connections in a truck102configured with an air heater controller104and an air heater106, according to the principles of the present disclosure. The air heater106selectively heats air being provided to an engine108. The air heater controller104may be activated by an engine controller110. The air heater controller104supplies voltage to the air heater106from a battery112. A starter114selectively rotates the crankshaft of the engine108and is also powered by the battery112.

As seen by the dashed line, the battery112provides power to the starter114, to the engine controller110, and to the air heater controller104, which selectively connects that power to the air heater106. Meanwhile, the solid lines show the ground connections of the battery to a frame116of the truck102as well as to the engine controller110. In some vehicles, the engine108is grounded to the frame116. This is simply one grounding configuration shown for example, and the principles of the present disclosure are not limited to this configuration.

The intake air heating system100includes a temperature sensor118that measures the temperature of the air heater106. For instance, the temperature sensor118measures a change in heater coil resistance from a cold ambient starting temperature to operating temperature. The change in resistance is provided to the air heater controller104and the air heater controller104can determine the temperature based upon the change in resistance. For example, the air heater controller104can maintain a look-up table that includes various resistance values and corresponding temperature values.

Other components, such as the air heater106and the starter114may be grounded through the engine108(in particular, the engine block) to the frame116. As a result, the effective ground voltage seen by the air heater106is based on the resistance of the ground path back to the battery112multiplied by the current following that same ground path. Generally, the starter114is not being powered at the same time as the air heater106.

Generally referring toFIGS. 2 through 5, an example air heater106is illustrated. As shown inFIG. 2, the air heater106is connected to and in thermal communication with an intake manifold200. The air heater106is also connected to an air supply conduit204via a flange206and one or more fasteners, such as bolts, screws, or the like. As shown inFIGS. 2 and 3, the air heater106includes a housing208that retains the one or more heating elements302of the air heater.

The air heater106includes a heater coil assembly300. The heater coil assembly300includes multiple heating elements302, as shown inFIGS. 3 through 5. The heating elements302may be a suitable resistive material, such as a stainless steel material, a nichrome material, an iron-chromium-aluminum material, and the like, that generates heat when a voltage is applied to the air heater106due to current flowing through the heating elements302. In one or more implementations, the respective heating elements302include multiple windings arranged in a serpentine configuration.

In some embodiments, the heating elements302may range in width from one centimeter to three centimeters (1 cm to 3 cm) and may range in length from thirty centimeters to fifty centimeters (30 cm to 50 cm) when arranged in the serpentine configuration. In some embodiments, the heating elements302may have a thickness ranging from twenty thousandths of a centimeter to thirty thousandths of a centimeter (0.02 cm to 0.03 cm). In an embodiment, the heating elements302have a width of two centimeters (2 cm), a length of forty centimeters (40 cm), and a thickness of twenty-five thousandths of a centimeter (0.025 cm).

The dimensional characteristics of the heating elements302serve to provide adequate support to the air heater106. For instance, air heater106can be heated to approximately four hundred degrees Celsius (400° C.) in approximately three seconds (3 sec.). In this instance, the air heater106generates a sufficient amount of heat within a defined time period while maintaining the integrity of the structure. For example, the dimensional characteristics of the heating elements302allow the air heater106to generate a sufficient amount of heat for a specific time period without melting and/or deforming. Additionally, the dimensional characteristics of the heating elements302allow the air heater106to a desired wattage within a defined time period (i.e., generate a sufficient wattage within ten seconds, etc.).

As shown, the heating elements302are arranged in a honeycomb configuration, or a honeycomb structure304. When assembled in the honeycomb configuration, the heating elements302define a plurality of apertures350, or openings, that allow airflow to pass through. The airflow passing through the apertures350absorbs the heat generated by the air heater106. In an implementation, the air heater106includes a first heating element302(1), a second heating element302(2), and third heating element302(3), and a fourth heating element302(4). Each heating element302(1) through302(4) includes a respective first end306and a respective second end308. Once assembled in the honeycomb structure304, the respective heating elements302(i.e., heating elements302(1) through302(4)) have at least substantially the same width, at least substantially the same length, and at least substantially the same thickness. Thus, in various embodiments, the respective heating elements302(1) through302(4) have at least substantially the same electrical resistance. The first heating element302(1) and the fourth heating element302(4) can be referred to as the exterior portions of the honeycomb structure304. The second heating element302(2) and the third heating element302(3) can be referred to as the interior portions of the honeycomb structure304. In some instances, the heating elements302may be selectively beveled to direct airflow in a preferred direction. Additionally, the honeycomb structure304may provide additional durability to mitigate the chances of the air heater106becoming inoperable due to vibrational forces.

Each heating element302(1) through302(4) includes a respective crest portion310and a respective trough portion312. The crest portion310of each heating element302represents the highest point of the respective heating element302when formed in the serpentine configuration, and the trough portion312of each heating element302represents the lowest point of the respective heating element302when formed in the serpentine configuration. It is understood that the crest portion310and the trough portion312are interchangeable since the air heater106can be oriented at one hundred and eighty degrees (180°) in various implementations.

The respective first ends306converge to form a first end314of the honeycomb structure304, and the respective second ends308converge to form a second end316of the honeycomb structure304. During operation, the first end314and the second end316of the honeycomb structure304function as electrodes that connect with a battery112.

Referring toFIG. 4, the respective crest portions310and the trough portions312are joined, or fastened, together to form respective interfaces352. For example, the respective trough portions312of the first heating element302(1) are fastened to the crest portions310of the second heating element302(2); the respective trough portions312of the second heating element302(2) are fastened to the crest portions310of the third heating element302(3); the respective trough portions312of the third heating element302(3) are fastened to the crest portions310of the fourth heating element302(4). In one or more implementations, the respective crest portions310and corresponding trough portions312can be welded together or fastened with a suitable fastener, such as a rivet, a screw, a bolt, or the like. The respective first ends306and the respective second ends308of the heating elements302can be welded together or fastened with a suitable fastener. In various implementations, the heating elements302(1) and302(4) include overlapping portions318,320,322,324that overlap a corresponding portion of the heating elements302(2) and302(3).

The air heater106is arranged within the housing208and in communication with the intake manifold200so that the air heater106provides uniform and adequate air heating to the engine108. As described herein, the voltage drop at the respective interfaces352, as well as in other portions (i.e., overlapping portions) that are fastened or adjacent to one another, is at least substantially zero.FIG. 5illustrates a diagrammatic schematic of an electrical interconnection400representing the heater coil assembly300according to an example embodiment. The electrical interconnection400includes parallel electrical paths402,404that include multiple resistance elements (i.e., R1through R20). The electrical interconnection also includes a first electrode406and a second electrode408. As shown, twelve volts is applied to the electrode406.FIG. 5illustrates an example voltmeter410that measures the electrical potential difference (i.e., voltage) at nodes412,414. Equation 1 models the voltage V1measured at node412:
V1=12(R3+R4+R5+R6+R7+R8+R9+R10)/(R1+R2+R3+R4+R5+R6+R7+R8+R9+R10)  EQN. 1

Assuming that R1=R11, R2=R12, R3=R13, . . . , R10=R20, then V1=V2. If V1=V2, no current flows from V1to V2even if the electrical paths were electrically connected (i.e., R1is connected to R11, R2is connected to R12, etc.). When the resistive elements are equal, equivalent points within the electrical interconnection400have the same voltage. Thus, the electrical paths402,404can be electrically connected but function, or behave, as electrically isolated paths (i.e., parallel electrical paths). WhileFIG. 5illustrates two electrical paths, it is understood that additional paths may be added without departing from the scope of the present disclosure. Additionally,FIG. 5illustrates the electrical interconnection400as including twenty resistive elements. However, it is understood that additional or less resistive elements can be utilized in accordance with the scope of the present disclosure as described above.

Referring back toFIG. 4, the respective heating elements302(1),302(2),302(3), and302(4) each represent an electrical path having multiple resistive elements. In various embodiments, a length of each electrical path (i.e.,302(1),302(2),302(3), and302(4)) measured from a first interface352(1) to an adjacent second interface352(2) is equivalent. Thus, each electrical path as measured from an interface352to another adjacent interface352functions as a resistive element (i.e., a first interface352to a second interface352corresponds to R1, a second interface352to a third interface352corresponds to R2, etc.). When a voltage is applied at the ends314,316from the battery112, at least substantially the same amount of current flows through each heating element302(1),302(2),302(3), and302(4) with no voltage drop at the interfaces352since each electrical path functions as an electrically isolated path.

For example, since each heating element302(1) to302(4) has at least substantially the same equivalent resistance per unit length resulting in the same resistance. Consequently, the same current flows through the respective heating elements302, and the voltage potentials caused by the currents times the resistance at the interfaces352is the same relative to insulated interfaces (i.e., a heater coil having insulating material disposed between a respective crest portion310and a respective trough portion312). Thus, each electrical path (i.e.,302(1),302(2),302(3),302(4)) within the heater coil assembly300functions, or behaves, as an independent, or parallel, electrical path with respect to the other electrical paths since there is no voltage drop between the fastened interfaces. When the interfaces352are welded together, the weld points are annealed during operation due to the heating and cooling cycles.

FIG. 6illustrates an example structure500, which includes elongated heating elements302arranged in a honeycomb configuration. For instance, a suitable material is manipulated to form a heating element302having a serpentine configuration, such as a material having multiple crest portions310and multiple trough portions312. The heating element302is then joined with another heating element302to form interfaces352. This process is continued until the heating elements302are assembled to form a honeycomb structure, such as the structure400illustrated inFIG. 6. The structure500can be segmented into multiple honeycomb structures304such that each segmented honeycomb structure304can utilized within an air heater126.

Generally referring back toFIG. 1, during operation, the air heater controller104controls voltage provided to the air heater106by the battery112. For example, the air heater controller104receives an enable signal to initiate operation of the air heater106from the engine controller110. In response, the air heater controller104causes the battery112to provide a voltage signal to the air heater106. For instance, the truck102includes electrical switches that selectively connect the battery112to the air heater106. When a voltage is applied to the ends314,316, current flows through the air heater106to generate heat.

The air heater controller104receives the measured temperature from temperature sensor118. The air heater controller104compares the measured temperature with a predefined temperature threshold. Once the measured temperature reaches or exceeds the predefined temperature threshold, the air heater controller104issues a control signal to prevent the battery112from providing further voltage to the air heater106. In various embodiments, the voltage can then be used by the starter114. In some instances, the air heater controller104allows the battery112to provide voltage to the air heater106while the starter114is using voltage from the battery112. In these instances, the air heater controller104reduces the voltage provided to the air heater106until the air heater controller104determines that a peak starter current used to break static friction has been reached. Once the peak current has been reached, the air heater controller104can increase the voltage provided to the air heater106to reduce exhaust emissions while the engine operates.

InFIG. 7, an example operation related to engine starting for the engine controller begins at700. The method begins at702. At704, a determination is made of whether a request to initiate operation of the engine108is received. For instance, the air heater controller104determines whether it has received an initiation signal from the engine controller110.

At706, the air heater controller104selectively connects the battery112to the air heater106. For instance, the air heater controller104causes electric switches electrically connected between the battery112and the air heater106to transition from an open state to a closed state allowing the battery112to be electrically connected to the air heater106. Additionally, the air heater controller104can initiate operation of the temperature sensor118to measure the temperature of the air heater106. In some examples, the temperature sensor118is disposed directly on a heating element302of the air heater106

At708, the air heater controller104compares the measured temperature to a predetermined temperature. As described above, the air heater controller104can employ a look-up table to determine the temperature of the heating coil based upon the measured resistance. Once the measured temperature is equal to or exceeds the predetermined temperature, the air heater controller104selectively disconnects to the air heater106from the battery112at710. At712, the method700ends.

InFIG. 8, an example operation related to engine starting for the engine controller begins at800. The method begins at802. At804, a determination is made of whether a request to initiate operation of the engine108is received. At806, the air heater controller104selectively connects the battery112to the air heater106at a predetermined voltage.

At808, the engine controller110compares the peak starter current to a predetermined peak starter current. For example, the engine controller110monitors parameters for a starter112. The engine controller110receives signals representing one or more starter114parameters (i.e., peak starter current, etc.) from a sensor associated with the starter114. Once a starter parameter, such as peak starter current, is equal to or exceeds a predetermined starter parameter, such as a predetermined peak starter current, the engine controller110transmits a signal to the air heater controller104to adjust the voltage provided from the battery112to the air heater106at810. For example, the voltage provided to the air heater106may be increased to increase the amount of current within the air heater106to shorten warm-up and reduce emissions. At812, the method800ends.