Apparatus and methods for synthesis of internal combustion engine vehicle sounds

A method of synthesizing sound signals associated with a vehicle having an engine, comprising:

• providing to an engine process model a plurality of engine control parameters which characterize respective engine control conditions, and
• generating, in response to an output from said engine process model, engine related sound signals corresponding to said engine control parameters,
• wherein the outputs from said engine process model comprise engine load and spark event signals which cooperate to generate at least one of engine resonance, air chop, one-shot sound file playback and exhaust system sound signals, and said engine load and spark event signals are supplied to an exhaust system model that includes at least one of explosion spreading, turbulence and filtering resonance models to generate said exhaust system sound signal, and
• wherein said load and spark event signals are supplied to an explosion spreading model within said exhaust system model which simulates the spreading of the initial pressure wave of an ignition explosion, and only said load signal is supplied to a turbulence model that simulates constrictions and/or bends in an exhaust system waveguide, and a filtering resonance model that simulates an exhaust muffler, the output of said explosion spreading model providing an input to said turbulence model, the output of said turbulence model providing an input to said filtering resonance model, and the output from said filtering resonance model providing said exhaust system sound signal.

Apparatus for synthesizing sound signals associated with a vehicle having an engine, comprising:

• an engine control input which provides a plurality of engine control parameters characterizing respective engine control conditions, and
• an engine related sound synthesizer which generates engine related sound signals corresponding to said engine control parameters,
• wherein said engine control input provides said engine control parameters to an engine process model, said engine related sound signal synthesizer generates said engine related sound signals in response to an output from said engine process model, the outputs from said engine process model comprise engine load, spark event and engine rotational speed signals, and said engine process model comprises an engine physical model which generates said spark event and engine rotational speed outputs, and a load behavior model which generates said engine load output,
• said engine physical model comprising a starter motor model which provides an initial engine shaft rotational speed signal in response to an engine start control signal, an angular integrator which generates an engine shaft angle signal from said engine shaft rotational speed signal, and a spark timing model that generates said spark event output to simulate the firing of sparks at multiple shaft angles in response to said engine shaft angle signal.

Apparatus for synthesizing sound signals associated with a vehicle having an engine, comprising:

• an engine control input which provides a plurality of engine control parameters characterizing respective engine control conditions, and
• an engine related sound synthesizer which generates engine relates sound signals corresponding to said engine control parameters,
• wherein said engine control input provides said engine control parameters to an engine process model, said engine related sound signal synthesizer generates said engine relates sound signals in response to an output from said engine process model, the outputs from said engine process model comprise engine load and spark event signals which cooperate to generate at least one of engine resonance, air chop, one-shot sound file playback and exhaust system sound signals, said engine process model supplies said engine load and spark event signals to an exhaust system model that includes at least one of explosion spreading, turbulence and filtering resonance models to generate said exhaust system sound signal, and
• wherein said engine process model supplies said load and spark event signals to an explosion spreading model within said exhaust system model which simulates the spreading of the initial pressure wave of an ignition explosion, and only said load signal to a turbulence model that simulates constrictions and/or bends in an exhaust system waveguide, further comprising a filtering resonance model that simulates an exhaust muffler, the output of said explosion spreading model providing an input to said turbulence model, the output of said turbulence model providing an input to said filtering resonance model, and the output from said filtering resonance model providing said exhaust system sound signal.