Engine controlling system which reduces the engine output upon detection of an abnormal condition

An engine controlling system for a vehicle, comprising:

• an accelerator pedal of said vehicle,
• an operation amount detecting means for detecting an operation amount of said accelerator pedal and developing a corresponding operation amount detection signal,
• a throttle valve for changing an amount of air to be taken into an engine of said vehicle to adjust an output power of said engine,
• a throttle valve control amount setting means for setting a control amount of said throttle valve in response to the operation amount detection signal,
• a throttle valve controlling means for controlling said throttle valve to open or close in response to the control amount,
• an abnormal condition detecting means for detecting an abnormal condition of at least one of said throttle valve controlling means and said throttle valve control amount setting means and developing a corresponding abnormal condition detection signal,
• a speed change gear means provided in said vehicle and having a plurality of gear positions,
• an automatic speed change gear controlling means for controlling changing over between the gear positions of said speed change gear means,
• a range changing over means for selectively setting a range of said speed change gear means at least to a running range or neutral range,
• a range detecting means for detecting a range set by said range changing over means and developing a corresponding range detection signal,
• an engine speed detecting means for detecting a rotational speed of said engine and developing a corresponding engine speed detection signal,
• an engine output reducing means for reducing the output power of said engine,
• and an output reduction control amount setting means for setting, when the abnormal condition detection signal is developed and the range detection signal indicates the neutral range, a control amount of said engine output reducing means such that a reduction of the output power of said engine is increased as the engine speed represented by the engine speed detection signal increases, but setting, when the abnormal condition detection signal is developed and the range detection signal indicates the running range, a control amount of said engine output reducing means such that the reduction of the output power of said engine is decreased as the accelerator pedal operation amount represented by the operation amount detection signal increases,
• wherein said throttle valve control amount setting means includes:
• an accelerator pedal operation condition detecting section for developing a treadled condition detection signal when it detects a treadled condition of said accelerator pedal but developing a treadled condition cancellation detection signal when it detects cancellation of a treadled condition of said accelerator pedal, a
• first control amount setting section for setting, when the treadled condition detection signal is developed, a control amount of said throttle valve in response to the operation amount detection signal, a running condition selecting section for selectively outputting, when the treadled condition cancellation detection signal is developed, either one of a constant speed running designating signal which designates constant speed running as an aimed running condition of said vehicle and an accelerated running designating signal which designates accelerated running as an aimed running condition of said vehicle,
• an aimed speed setting section for setting, when the constant speed running designating signal is developed, an aimed speed of said vehicle for the constant speed running, a running speed of said vehicle and developing a corresponding running speed detection signal,
• a second control amount setting section for setting, when the constant speed running designating signal is developed, a control amount of said throttle valve with which the running speed of said vehicle represented by the running speed detection signal is to be made equal to the aimed speed,
• an accelerated running aimed acceleration setting section for setting, when the accelerated running designating signal is developed, an aimed acceleration for the accelerated running of said vehicle, and
• a third control amount setting section for setting, when the accelerated running designating signal is developed, a control amount of said throttle valve in response to the aimed acceleration set by said accelerated gunning aimed acceleration setting section.