Engine device

1. An engine device comprising:

an engine which serves as a power source and has a rotating speed, the rotating speed including an operating rotating speed during a work operation;

an exhaust gas purifying filter device which is arranged in a path of an exhaust gas of the engine; and

a control means for coordinating lowering and raising of engine speed to achieve forced regeneration of said filter device during presence of a plurality of low rotation conditions, said control means being configured

to execute a low rotation control for lowering speed of the engine toward a predetermined first low rotating speed automatically in response to detection of the plurality of low rotation conditions,

to test for a forced regeneration condition during said low rotation control, and

to execute forced regeneration control when each one of two conditions are concurrently present, a first condition of the two conditions being that low rotation control is being executed, a second condition of the two conditions being that the forced regeneration condition is detected; and

wherein during said forced regeneration control, said control means is configured to modify said low rotation control, while the engine speed is being lowered toward the first low rotating speed, to a second rotation control for achieving a second low rotating speed, which is higher than the first low rotating speed, said second rotation control for suppressing a reduction of temperature of the exhaust gas so that filter regeneration may occur;

wherein, when said second rotation control ends in response to a termination of said filter forced regeneration condition before completion of said low rotation control, the control means is configured to resume lowering the engine speed to the first low rotating speed; and

wherein the control means is further configured to achieve and maintain the engine speed at the first low rotating speed when the filter forced regeneration condition is not detected, and

to adjust the engine speed back toward the operating rotating speed that prevailed before the low rotation conditions and the filter forced regeneration condition were established only after the low rotation conditions and forced regeneration condition have ended.

2. An engine device comprising:

an engine which serves as a power source;

an exhaust gas purifying filter device which is arranged in an exhaust gas path of the engine;

a control means which is configured to detect a forced regeneration condition of the filter device and to execute a forced regeneration control of the filter device; and

a forced low rotation switch coupled to the control means and that causes execution of a forced low rotation control by the control means which forcibly lowers the engine speed toward a predetermined low rotating speed; and

wherein the control means is configured to test for said forced regeneration condition during said forced low rotation control, while the engine speed is being lowered toward the first low rotating speed;

wherein the control means is configured to execute the forced regeneration control upon detection of two conditions being concurrently present, a first of the two conditions being that said low rotation control is being executed, and a second of the two conditions being that the filter forced regeneration condition is detected during said test for said forced regeneration condition;

wherein during said forced regeneration control, said control means is configured to modify said forced low rotation control to achieve a second low rotating speed, which is higher than the first low rotating speed, said forced regeneration control for suppressing a reduction of temperature of the exhaust gas so that filter regeneration may occur; and

wherein, when said forced regeneration control ends in response to a termination of said filter forced regeneration condition before completion of said low rotation control, the control means being configured to resume lowering the engine speed to the first low rotating speed.