External vehicle sound field enhancement

An engine sound enhancement system includes a conduit in communication with at least one of an intake manifold and an exhaust manifold of an engine. An interface is arranged at least one of within the conduit and between an inlet of the conduit and the at least one of the intake manifold and the exhaust manifold. The interface is responsive to pulses within the at least one of the intake manifold and the exhaust manifold, wherein the interface is configured to transfer the pulses into the conduit.

FIELD

The present disclosure relates to internal combustion engines, and more specifically, to systems and methods for enhancing engine sounds.

BACKGROUND

Automotive vehicles, especially performance automotive vehicles, may implement one or more engine sound enhancement features. For example, as internal combustion engine technology improves with respect to combustion efficiency, emissions, fuel economy, engine output, etc., engine sound (both engine sound as experienced by a driver and/or passengers within the vehicle as well as engine sound external to the vehicle) may be significantly reduced. Accordingly, various engine sound enhancement features may be implemented to adjust the magnitude, frequency, tone, etc. of the sound generated by the engine through the exhaust system.

SUMMARY

An engine sound enhancement system includes a conduit in communication with at least one of an intake manifold and an exhaust manifold of an engine. An interface is arranged at least one of within the conduit and between an inlet of the conduit and the at least one of the intake manifold and the exhaust manifold. The interface is responsive to pulses within the at least one of the intake manifold and the exhaust manifold, wherein the interface is configured to transfer the pulses into the conduit.

An engine sound enhancement method includes providing a conduit in communication with at least one of an intake manifold and an exhaust manifold of an engine, and arranging an interface at least one of within the conduit and between an inlet of the conduit and the at least one of the intake manifold and the exhaust manifold. The interface is responsive to pulses within the at least one of the intake manifold and the exhaust manifold. The method further includes transferring the pulses into the conduit using the interface.

DETAILED DESCRIPTION

Various air intake, exhaust, and combustion components of an engine may affect sound generated by the engine. Some components may reduce or otherwise change the character of engine sound, which may be undesirable. For example, in turbocharged vehicles, a turbocharger may act as a sound filter and interfere with desired engine sounds. Engine sound enhancement systems and methods according to the principles of the present disclosure implement an engine sound enhancement device and/or engine sound flow path to enhance engine sounds.

Referring now toFIG. 1, an engine system100includes an engine102that combusts an air/fuel mixture to produce drive torque for a vehicle. Although described with respect to gasoline internal combustion engines, the principles of the present disclosure may also be applied to diesel fuel engines. The amount of drive torque produced by the engine102is based on a driver input from a driver input module104. The driver input may be based on a position of an accelerator pedal. The driver input may also be based on a cruise control system, which may be an adaptive cruise control system that varies vehicle speed to maintain a predetermined following distance.

Air is drawn into the engine102through an intake system108. The intake system108includes an intake manifold110and a throttle valve112. The throttle valve112may include a butterfly valve having a rotatable blade. An engine control module (ECM)114controls a throttle actuator module116, which regulates opening of the throttle valve112to control the amount of air drawn into the intake manifold110.

Air from the intake manifold110is drawn into cylinders of the engine102. While the engine102may include multiple cylinders, for illustration purposes a single representative cylinder118is shown. For example only, the engine102may include 2, 3, 4, 5, 6, 8, 10, and/or 12 cylinders. The ECM114may deactivate some of the cylinders, which may improve fuel economy under certain engine operating conditions.

The engine102may operate using a four-stroke cycle. The four strokes, described below, are named the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. During each revolution of a crankshaft (not shown), two of the four strokes occur within the cylinder118. Therefore, two crankshaft revolutions are necessary for the cylinder118to experience all four of the strokes.

During the intake stroke, air from the intake manifold110is drawn into the cylinder118through an intake valve122. The ECM114controls a fuel actuator module124, which regulates fuel injections performed by a fuel injector125to achieve a desired air/fuel ratio. Fuel may be injected into the intake manifold110at a central location or at multiple locations, such as near the intake valve122of each of the cylinders. In various implementations, fuel may be injected directly into the cylinders or into mixing chambers associated with the cylinders. The fuel actuator module124may halt injection of fuel to cylinders that are deactivated.

The injected fuel mixes with air and creates an air/fuel mixture in the cylinder118. During the compression stroke, a piston (not shown) within the cylinder118compresses the air/fuel mixture. The engine102may be a compression-ignition engine, in which case compression in the cylinder118ignites the air/fuel mixture. Alternatively, the engine102may be a spark-ignition engine, in which case a spark actuator module126energizes a spark plug128to generate a spark in the cylinder118based on a signal from the ECM114, which ignites the air/fuel mixture. The timing of the spark may be specified relative to the time when the piston is at its topmost position, referred to as top dead center (TDC).

The spark actuator module126may be controlled by a spark timing signal specifying how far before or after TDC to generate the spark. Because piston position is directly related to crankshaft rotation, operation of the spark actuator module126may be synchronized with crankshaft angle. In various implementations, the spark actuator module126may halt provision of spark to deactivated cylinders.

Generating the spark may be referred to as a firing event. The spark actuator module126may have the ability to vary the timing of the spark for each firing event. The spark actuator module126may even be capable of varying the spark timing for a next firing event when the spark timing signal is changed between a last firing event and the next firing event. In various implementations, the engine102may include multiple cylinders and the spark actuator module126may vary the spark timing relative to TDC by the same amount for all cylinders in the engine102.

During the combustion stroke, combustion of the air/fuel mixture drives the piston down, thereby driving the crankshaft. The combustion stroke may be defined as the time between the piston reaching TDC and the time at which the piston returns to bottom dead center (BDC). During the exhaust stroke, the piston begins moving up from BDC and expels the byproducts of combustion through an exhaust valve130. The byproducts of combustion are exhausted from the vehicle via an exhaust system134.

The intake valve122may be controlled by an intake camshaft140, while the exhaust valve130may be controlled by an exhaust camshaft142. In various implementations, multiple intake camshafts (including the intake camshaft140) may control multiple intake valves (including the intake valve122) for the cylinder118and/or may control the intake valves (including the intake valve122) of multiple banks of cylinders (including the cylinder118). Similarly, multiple exhaust camshafts (including the exhaust camshaft142) may control multiple exhaust valves for the cylinder118and/or may control exhaust valves (including the exhaust valve130) for multiple banks of cylinders (including the cylinder118).

The time at which the intake valve122is opened may be varied with respect to piston TDC by an intake cam phaser148. The time at which the exhaust valve130is opened may be varied with respect to piston TDC by an exhaust cam phaser150. A valve actuator module158may control the intake and exhaust cam phasers148and150based on signals from the ECM114. When implemented, variable valve lift may also be controlled by the valve actuator module158.

The ECM114may deactivate the cylinder118by instructing the valve actuator module158to disable opening of the intake valve122and/or the exhaust valve130. The valve actuator module158may disable opening of the intake valve122by decoupling the intake valve122from the intake camshaft140. Similarly, the valve actuator module158may disable opening of the exhaust valve130by decoupling the exhaust valve130from the exhaust camshaft142. In various implementations, the valve actuator module158may actuate the intake valve122and/or the exhaust valve130using devices other than camshafts, such as electromagnetic or electrohydraulic actuators.

The engine system100may include a boost device that provides pressurized air to the intake manifold110. For example,FIG. 1shows a turbocharger including a hot turbine160-1that is powered by hot exhaust gases flowing through the exhaust system134. The turbocharger also includes a cold air compressor160-2, driven by the turbine160-1, which compresses air leading into the throttle valve112. In various implementations, a supercharger (not shown), driven by the crankshaft, may compress air from the throttle valve112and deliver the compressed air to the intake manifold110.

A wastegate162may allow exhaust to bypass the turbine160-1, thereby reducing the boost (the amount of intake air compression) of the turbocharger. The ECM114may control the turbocharger via a boost actuator module164. The boost actuator module164may modulate the boost of the turbocharger by controlling the position of the wastegate162. In various implementations, multiple turbochargers may be controlled by the boost actuator module164. The turbocharger may have variable geometry, which may be controlled by the boost actuator module164.

An intercooler (not shown) may dissipate some of the heat contained in the compressed air charge, which is generated as the air is compressed. The compressed air charge may also have absorbed heat from components of the exhaust system134. Although shown separated for purposes of illustration, the turbine160-1and the compressor160-2may be attached to each other, placing intake air in close proximity to hot exhaust.

The exhaust system134may include an exhaust gas recirculation (EGR) valve170, which selectively redirects exhaust gas back to the intake manifold110. The EGR valve170may be located upstream of the turbocharger's turbine160-1. The EGR valve170may be controlled by an EGR actuator module172.

The engine system100may measure the position of the crankshaft using a crankshaft position (CKP) sensor180. The temperature of the engine coolant may be measured using an engine coolant temperature (ECT) sensor182. The ECT sensor182may be located within the engine102or at other locations where the coolant is circulated, such as a radiator (not shown).

The pressure within the intake manifold110may be measured using a manifold absolute pressure (MAP) sensor184. In various implementations, engine vacuum, which is the difference between ambient air pressure and the pressure within the intake manifold110, may be measured. The mass flow rate of air flowing into the intake manifold110may be measured using a mass air flow (MAF) sensor186. In various implementations, the MAF sensor186may be located in a housing that also includes the throttle valve112.

The throttle actuator module116may monitor the position of the throttle valve112using one or more throttle position sensors (TPS)188. The ambient temperature of air being drawn into the engine102may be measured using an intake air temperature (IAT) sensor189. The ECM114uses signals from the sensors to make control decisions for the engine system100.

The ECM114may communicate with a transmission control module (TCM)190to coordinate shifting gears in a transmission (not shown). For example, the ECM114may reduce engine torque during a gear shift. The ECM114may communicate with a hybrid control module (HCM)191to coordinate operation of the engine102and an electric motor192. The electric motor192may also function as a generator, and may be used to produce electrical energy for use by the vehicle's electrical systems and/or for storage in a battery. In various implementations, various functions of the ECM114, the TCM190, and the HCM191may be integrated into one or more modules.

The engine system100implements one or more engine sound enhancement features according to the principles of the present disclosure. For example, a conduit193may be provided in communication with the intake manifold110. The conduit193provides a sound flow path from the intake manifold110to one or more other locations throughout the engine system100. For example, the conduit193may provide sound flow between the intake manifold and an air intake (e.g., a cold air intake, snorkel, etc.)194, and/or to an exterior of the vehicle (e.g., via external port195). Alternatively or additionally, a conduit196may be provided in communication with exhaust manifold197. The conduit196may provide a sound flow path from the exhaust manifold197to one or more other locations throughout the engine system100including, but not limited to, the air intake194and/or the exhaust system134(e.g., an exhaust pipe).

Each of the conduits193and196may include one or more engine sound enhancement devices198. The engine sound enhancement devices198may include, but are not limited to, a mechanical device for amplifying sound (e.g., a membrane that resonates in response to sound pulses received through the conduits193and196), an electronic device (e.g., a microphone and speaker), a combination mechanical and electronic device, etc. Each of the conduits193and196may also include one or more valves199. The valves199may be actuated (i.e., opened and closed) to selectively provide and prevent engine sound enhancement. For example, the ECM114selectively actuates the valves based on various inputs and performance parameters, including, but not limited to, a selected performance mode and/or other user inputs, engine speed, torque, vehicle speed, other engine sound enhancement features, noise thresholds, etc.

FIGS. 2A, 2B, and 2Cshow respective example engine sound enhancement systems200-1,200-2, and200-3, referred to collectively as engine sound enhancement systems200. Each of the systems200communicate with various portions of an intake manifold204and/or an exhaust manifold208, which are in turn in fluid communication with an engine212and a turbocharger216. InFIG. 2A, a conduit220provides a sound flow path from the intake manifold204to an exterior of the vehicle (e.g., via external port224). InFIG. 2B, a conduit228provides a sound flow path from the intake manifold204to an air intake232(e.g., to the air intake232, a snorkel236, etc.). InFIG. 2C, a first conduit240provides a sound flow path from the intake manifold204to the air intake232. A second conduit244provides a sound flow path from the exhaust manifold208to the air intake232and a sound flow path from the exhaust manifold208to an exhaust pipe248. For example only, the second conduit244may communicate with a waste gate channel of the exhaust manifold208.

Each of the systems includes engine sound enhancement devices252-1,252-2,252-3, and252-4(referred to collectively as engine sound enhancement devices252) arranged in the sound flow paths of the respective conduits220,228,240, and244. The engine sound enhancement devices252are responsive to pulses (e.g., acoustic/pressure pulses) in the intake manifold204and the exhaust manifold208. For example, the devices252may include a membrane that resonates in response to the pulses and/or an electronic device (e.g., a microphone and speaker). The electronic device would convert the pulses to signals to be output by the speaker. The signals may be amplified, and/or modified (e.g., filtered) to remove undesirable characteristics (e.g., undesirable resonances, frequencies, tones, etc.).

The conduits220,228,240, and244may or may not be in fluid communication with the intake manifold204and the exhaust manifold208, respectively. For example, a diaphragm, membrane, or other type of interface254may be arranged in respective inlets of the conduits between the conduits and intake manifold204or exhaust manifold208, and/or merely adjacent to surfaces of the intake manifold204or exhaust manifold208. Additionally or alternatively, the interfaces254may be provided within the respective devices252. The interfaces254do not allow exhaust or intake air flow into the conduits. Instead, the interfaces254are responsive to pulses in the intake manifold204and the exhaust manifold208. For example, the interfaces254may be responsive to changes in pressure, sound, etc. within the intake manifold204and the exhaust manifold208. The interfaces254may resonate or vibrate and transfer associated sound and pressure changes into the conduits, devices252, etc. In embodiments that include electronic components (e.g., a microphone and/or speaker), the interfaces254may include sound transducers that convert the sound or pressure changes into an electronic signal.

In this manner, enhanced engine sound is provided to an exterior of the vehicle via the port224, the air intake232(e.g., via the snorkel236), and/or the exhaust pipe248without interfering with intake air flow or exhaust flow. Valves256-1,256-2,256-3,256-4, and256-5(referred to collectively as valves256) may be provided in the sound flow paths of the respective conduits220,228,240, and244. The valves256are selectively actuated to modulate engine sound enhancement as described below in further detail.

Referring now toFIG. 3, an example engine sound enhancement method300begins at304. At308, engine sound enhancement valves (e.g., the valves256) are actuated to a default position (e.g., upon engine start up, in response to control signals received from the ECM114). While the default position corresponds to a fully open position in the present example, the default position may correspond to a closed or intermediate (partially open or partially closed) position in other examples. At312, the method300(e.g., the ECM114) determines whether sound caused by the engine with the valves in the present position is greater than a threshold. If true, the method300continues to316. If false, the method300continues to320. For example, the threshold may be predetermined or calibrated, adjustable based on user inputs (such as a selected engine performance mode), adjustable based on location (e.g., as determined according to GPS signals), etc. The sound caused by the engine may be calculated (e.g., by the ECM114) based on engine parameters including, but not limited to, engine speed, torque, vehicle speed, selected transmission gear, etc.

At316, the method300(e.g., the ECM114) reduces the openings of the valves. At320, the method300(e.g., the ECM114) determines whether the valves are closed. If true, the method300continues to324. If false, the method300continues to328. At324, the method300(e.g., the ECM114) increases the openings of the valves.

At328, the method300(e.g., the ECM114) determines whether the engine sound (e.g., as calculated according to speed, torque, etc.) is consistent with other engine sound enhancement (ESE) features of the vehicle. For example, other ESE features include, but are not limited to, sound quality valves located throughout the exhaust system of the vehicle that may be opened and closed to adjust engine sound, engine sound enhancement features implemented by an interior audio system of the vehicle, etc. If true, the method300continues to312. If false, the method300continues to332.

At332, the method300(e.g., the ECM114) adjusts the openings of the valves based on other ESE features. For example, if other ESE features are reduced, the openings of the valves may be reduced. If the other ESE features are disabled (e.g., a selected performance mode disables all ESE features), the valves may be closed.

Although, as described above, the method300reduces and increases the openings of each of the valves at316,324, and332, in other examples the valves may be actuated independently of one another. The valves may be adjusted in predetermined increments or using any other suitable control scheme.