Abstract: Provided is a breather pipe structure for a liquid reducing agent storage tank which ensures that a liquid reducing agent can be supplied without trouble even if a breather pipe in the liquid reducing agent storage tank is clogged with frozen liquid reducing agent. In a breather pipe structure for a liquid reducing agent storage tank (10) which stores a liquid reducing agent (5) and which has a breather pipe (20) for introducing/discharging air attached on top of the liquid reducing agent storage tank (10), a lower end (20c) of the breather pipe (20) in the liquid reducing agent storage tank (10) is arranged to extend along a liquid reducing agent defrosting piping (16) provided in the liquid reducing agent storage tank (10).

Abstract: A urea quality diagnosis system capable of accurately diagnosing the quality of an aqueous urea solution in a urea tank. A concentration and a level (L) of an aqueous urea solution inside a urea tank 16 are detected, and the quality of the aqueous urea solution is diagnosed based on a detected value of the concentration of the aqueous urea solution when the level L is equal to or higher than a predetermined value.

Abstract: In forced regeneration control of an exhaust gas purification device 12, data for control such as the number of meshes of a data map and the number of data maps for forced regeneration control is reduced and occurrence of torque shock is avoided by smoothly changing a fuel pressure. In the forced regeneration control of the exhaust gas purification device, when an operation state of an internal combustion engine is in a high-load operation state, normal injection control by stopping multi injection is carried out and according to a rotation speed and a load of the internal combustion engine, a region for control is divided into a multi-injection control region, a transition region, and a normal injection control region, and in the transition region, data for fuel pressure control obtained by interpolation of data for fuel pressure control on the multi-injection control region side and data for fuel pressure control on the normal injection control region side is used.

Abstract: Forced regeneration start timing of a diesel particulate filter for purifying particulate matter in exhaust gas is judged based on a comparison of a differential pressure across the diesel particulate filter with a predetermined differential pressure threshold across the filter. The predetermined differential pressure threshold is set by multiplying a reference differential pressure threshold by a coefficient which varies stepwise or continuously depending on a mileage of a vehicle after previous forced regeneration. Consequently, particulate matter can be removed by burning while the amount of particulate matter accumulated unevenly in the filter is still small, and excessive temperature rise in the filter resulting from excessive accumulation of particulate matter during forced regeneration and melting-loss of the filter due to excessive temperature rise can be prevented.

Abstract: In forced regeneration control of an exhaust gas purification device a number of data for injection control, such as a number of meshes of a data map and a number of data maps for multi injection control, is decreased while occurrence of torque shock, which is a rapid fluctuation of a generated torque, is avoided. In this forced regeneration control, when an operation state of an internal combustion engine is a high-load operation state, the normal injection control by stopping the multi injection is carried out and, according to a rotation speed and a load of the internal combustion engine, a region for control is divided into a multi-injection control region, a transition region, and a normal injection control region. In the transition region, data for injection control obtained by interpolation of data for injection control on the multi-injection control region side and data for injection control on the normal injection control region side is used.

Abstract: In in-cylinder fuel multi-injection conducted during forced regeneration of a diesel particulate filter (“DPF”), control maps for multi-injection are constructed so as to be different for a first gas temperature raising control, which raises a catalyst temperature index temperature to a first judgment temperature only by multi-injection, and for a subsequent second exhaust gas temperature raising control, wherein post-injection is conducted in addition to multi-injection to raise a filter temperature index temperature to a second judgment temperature. In so doing, exhaust gas flowing into the DPF can be rapidly raised in temperature when performing forced regeneration of the DPF, thereby shortening the forced regeneration time and improving fuel consumption for forced regeneration.

Abstract: When an internal combustion engine is in a low rotation speed driving condition, a duration of the low rotation speed driving condition is measured, and when this duration exceeds a predetermined time, the forced regeneration control is performed. Thus, even when an exhaust flow rate is small and an estimation of a particulate matter accumulated amount due to a pressure difference between front and back sides of a filter is difficult, a forced regeneration time can be accurately judged, the deterioration of fuel efficiency that is caused by excessive trapped particulate matter can be avoided, and thermal runaway that is caused by the excessive particulate matter, and the melting damage of the diesel particulate filter due to this thermal runaway, can be prevented.

Abstract: An exhaust emission purification system having a controller performing exhaust temperature rise control including multistage delay injection control for raising the exhaust temperature, if the exhaust gas temperature is lower than a predetermined judgment temperature, and performing particulate matter combustion removal control including post injection control, if the exhaust gas temperature becomes equal to or higher than the predetermined judgment temperature, when forced regeneration of a diesel particulate filter is carried out. The multistage delay injection control is forbidden when an idle operation state of an internal combustion engine occurs for a predetermined judgment time and a power take-off device is operating.

Abstract: Provided is a breather pipe structure for a liquid reducing agent storage tank which ensures that a liquid reducing agent can be supplied without trouble even if a breather pipe in the liquid reducing agent storage tank is clogged with frozen liquid reducing agent. In a breather pipe structure for a liquid reducing agent storage tank (10) which stores a liquid reducing agent (5) and which has a breather pipe (20) for introducing/discharging air attached on top of the liquid reducing agent storage tank (10), a lower end (20c) of the breather pipe (20) in the liquid reducing agent storage tank (10) is arranged to extend along a liquid reducing agent defrosting piping (16) provided in the liquid reducing agent storage tank (10).

Abstract: A urea quality diagnosis system capable of accurately diagnosing a quality of an aqueous urea solution in a urea tank. A concentration and a level L of an aqueous urea solution inside a urea tank 16 are detected, and the quality of the aqueous urea solution is diagnosed based on a detected value of the concentration of the aqueous urea solution when the level L is equal to or higher than a predetermined value.

Abstract: In emergency regeneration, i.e., after a judgment is made that purification is insufficient after ending forced regeneration, forced regeneration has expired before completion, or when a pressure difference across a diesel particulate filter exceeds a predetermined first judging pressure difference when traveling distance of a vehicle is shorter than a predetermined distance, an alarm for urging manual regeneration is issued. When manual regeneration is designated thereafter by the vehicle's user, manual regeneration is performed. When predetermined conditions are satisfied before receiving a designation of manual regeneration, automatic regeneration is performed.

Abstract: An exhaust emission purification system and a related method of control, wherein an exhaust throttle valve is opened if an engine load reaches at least a predetermined first judgment value during execution of forced regeneration control, and generating an alarm of failure of the exhaust throttle valve if the engine load reaches at least a second judgment value which is larger than the predetermined first judgment value.

Abstract: An exhaust gas purification system has an exhaust gas purification device for purifying components in exhaust gas from an internal combustion engine. In order to recover a purification ability of the device, and in order to prevent oil dilution occurring when post injection is conducted during control that raises the temperature of exhaust gas, the system performs the following, during control; injection quantities of post injections are calculated based on previously set map data, accumulated to calculate a post injection accumulated injection amount, and, when the accumulated injection amount exceeds a predetermined value, the post injection is stopped to cease the regenerative control.

Abstract: In an exhaust gas temperature raising control for recovering purification ability of an exhaust gas purification device of an internal combustion engine, the exhaust gas temperature is efficiently raised to a target level without producing white smoke. In recovery control of the exhaust gas purification device, when the temperature of the exhaust gas flowing into the exhaust gas purification device is lower than a predetermined judgment value, a first exhaust gas temperature raising control that does not include post injection but includes intake air restriction is performed, and when equal to or higher than the predetermined judgment value, a second exhaust gas temperature raising control that includes both the post injection and the intake air restriction is performed to set an intake air restriction amount in the first exhaust gas temperature raising control greater than an intake air restriction amount in the second exhaust gas temperature raising control.

Abstract: In regeneration control in a manual regeneration mode, when a first exhaust gas temperature of an exhaust gas flowing into an oxidation catalyst device is higher than a predetermined determining temperature and an exhaust gas temperature flowing into a DPF device is higher than a predetermined determining temperature and when an intake temperature becomes higher than a predetermined third determining temperature, second exhaust gas temperature control carrying out post injection in addition to multi injection is stopped and switched to third exhaust gas temperature rise control carrying out the post injection in addition to normal injection. Thus, temperature rise of an engine cooling water can be restricted without stopping an air conditioner, and possible overheating of the engine can be prevented.

Abstract: At regeneration control while a vehicle mounting an internal combustion engine (10) is parked, both an exhaust throttle valve (13) and an exhaust brake valve (18) are used and if a catalyst temperature index temperature (Tg2) is lower than a predetermined first determining temperature (Tc1), first exhaust gas temperature rise control is conducted that the exhaust brake valve (18) is set to a fully closed side and multiple injection is carried out in in-cylinder fuel injection control, while if a catalyst temperature index temperature (Tg2) is equal to the predetermined first determining temperature (Tc1) or above, second exhaust gas temperature rise control is conducted that the exhaust brake valve (18) is set to an open side, the exhaust throttle valve (13) is set to the fully closed side, and post injection is carried out in the in-cylinder fuel injection control.

Abstract: In regeneration control, when the catalyst temperature index temperature (Tg2) using the temperature of the oxidation catalyst (12a) as an index is below a predetermined first determination temperature (Tc1), the engine speed of idling is brought to a predetermined first target engine speed (Nei1) which is higher than the engine speed of idling (Nei0) in the ordinary operation, and, further, multi-injection is carried out. On the other hand, when the catalyst temperature index temperature (Tg2) is the predetermined first determination temperature (Tc1) or above, the engine speed of idling is brought to a predetermined second target engine speed (Nei2), which is lower than the predetermined first target engine speed (Nei1) and is higher than the engine speed of idling (Nei0) in ordinary operation, and, further, post injection is carried out, followed by raising of the temperature of an exhaust gas flown into a DPF apparatus (12b) to a predetermined second determination temperature (Tc2).

Abstract: In an exhaust gas purification system (1) for conducting control of raising temperature of a DPF (12b) by supplying an unburned fuel to an upstream side of an oxidation catalyst to oxidize it, a minimum value (Qumin) of a first upper limit value (Qu1) acquired by subtracting a fuel injection amount (Qe) for in-cylinder combustion from a first combustible fuel amount (Qa1) limited by an air/fuel ratio, a second upper limit value (Qu2) acquired by subtracting the fuel injection amount (Qe) for in-cylinder combustion from a second combustible fuel amount (Qa2) limited by an atmospheric pressure, and a third upper limit value (Qu3), which is a third combustible fuel amount (Qa3) which can be oxidized by the oxidation catalyst limited by a catalyst temperature index temperature (Tg1, Tg2) and an engine speed (Ne) is set as an upper limit value (Qu) for the unburned fuel supply amount (Qp).

Abstract: An exhaust emission control system including a continuous regenerating diesel particulate filter (“DPF”) and a DPF controller, wherein a forced regenerator is operated by a driver's request, when it is judged that a traveling distance, after starting particulate matter collection, detected by a traveling distance detector has reached a predetermined judging traveling distance, even when the DPF controller detects that a collection amount detected by a collection amount detector is smaller than a prescribed judging collection amount. Accordingly, in a continuous regenerating DPF capable of manual regenerating, the number of warnings, such as a blinking regeneration button prompting a manual regeneration, is reduced to relieve a driver of annoyance or inconvenience.

Abstract: A method (1) of controlling an exhaust gas purification system has a DPF device (12), where a regeneration control means (35C) has a forced regeneration mode and an arbitrary regeneration mode. In the forced regeneration mode, when it is determined by a regeneration time determination means (34C) that it is time to regenerate a filter (12b) and the temperature of exhaust gas is low, the exhaust gas temperature is raised by an exhaust gas temperature raising means (351C) to forcibly regenerate the filter (12b). In the arbitrary regeneration mode, the filter is arbitrary regenerated based on the result of detection by a collection amount detection means (32C). While the temperature of exhaust gas is raised in the arbitrary regeneration mode by the exhaust gas temperature raising means (351C), operation of a compressor (41) of a vehicle air conditioner is stopped.