FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION,
(See Section 10; rule 13) TITLE OF THE INVENTION
Low Emission Indirect Injection Diesel Engine
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Mr. Fetkar R M, Mr. Katkar D R
Mr. Bhandari R V, Mr. Kulkarni D S
Mr. Sathyanarayanan G, Mr. Dwivedi A K
all Indian nationals of
TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF INVENTION:
This invention relates to indirect injection diesel engines, more particularly, it deals with low emission indirect injection diesel engine. It refers to design modifications and after treatment systems used for this engine. These modifications can be carried out in new as well as in use engines & vehicles.
BACKGROUND OF THE INVENTION:
Stricter emissions norms and environmental friendliness of engines are driving forces for development in engine emission technology. In order to address these challenges, various technologies have emerged out. In case of diesel engines, one approach is to change the engine technology which leads to common rail, HCCI etc. The other approach is to adapt appropriate new technology suitably to existing engine. Addition of electronic controls along with feedback signals also show positive trend since with these controls, it is possible to optimize the parameters point by point.
If similar technology is added on to mechanically fuelled engines it would result in similar effects. The present invention aims at developing low emission indirect injection diesel engine. The base engine is modified suitably to incorporate EGR cooler, various sensors that are necessary for EGR control operation & to lower engine out emissions. A stand alone EGR controller is developed which regulates the EGR flow into the engine thereby controlling NOx emissions. Innovative EGR control strategies are developed for this purpose. The after treatment system comprises of oxidation catalyst and partial particulate trap. The entire system comprising of modified engine, standalone EGR controller along with EGR control strategies & the after treatment system are matched to each other to achieve optimum performance.
One Prior Art teaches about the high speed indirect injection diesel engine. A diesel engine has a pre-combustion chamber with an angled and tapered transfer passage leading to the main combustion chamber. The transfer passage is tapered to provide a larger lower end facing the main chamber and smaller upper end facing the pre-combustion chamber. Air

passing through the passage during the compression stroke undergoes heating and swirling within the pre-combustion chamber. The piston has an upper surface with recessed lobes and recessed passage area. Each recessed lobe functions as a valve pocket for the respective intake valve and exhaust valve. The valve pockets are deep enough to provide sufficient valve lifts to allow valve overlap periods comparable with spark ignition gasoline engines without interfering with the piston upper surface.
Another Prior Art teaches about the self-regenerating diesel exhaust particulate filter. The self-regenerating catalyst member which may be used to remove particulate carbon and residual hydro carbonaceous material from engine exhaust, especially those emanating from the diesel engines. The oxidation catalyst placed onto a particulate trap or collector and placed in the exhaust circuit of a diesel engine. The catalytic material involved is specially formulated to form large particulates, multi-metal oxide based catalytic particles. The catalytic particles may be perovskites. The catalytic material include at least one member selected from group IB metals, preferably copper, and one member selected from group VIII metal (iron) and compounds and Group 5B metals(vanadium). The specific method of preparing the active oxidation components of the composition is believed to provide the improved composition,
OBJECT OF THIS INVENTION:
• The main object of this invention is to obviate above mentioned drawbacks by providing a low emission indirect injection diesel engine.
• Yet another object of this invention is to provide a low emission indirect injection diesel engine that is having mechanical fuel injection system.
• Yet another object of this invention is to provide a low emission indirect injection diesel engine with emission control at engine as well as by after treatment.
• Yet another object of this invention is to provide a low emission indirect injection
diesel engine having emission control system that protects the engine under extreme
operating conditions.

• Yet another object of this invention is to provide a low emission indirect injection diesel that is robust & simple.
• Yet another object of this invention is to provide design improvements for low emission indirect injection diesel engine that can be retrofitted in in-use vehicles.
• Yet another object of this invention is to provide cost effective low emission indirect injection diesel engine.
• Yet another object of this invention is to provide a low emission indirect injection diesel engine, which has self regeneration capability
BRIEF DESCRIPTION:
The sketches showing details of the arrangement of components for a low emission indirect diesel engine are given herewith.
Fig. 1 shows the arrangement of components & configuration of the low emission indirect
injection diesel engine in accordance with the present invention.
Fig 2 shows the view that shows the EGR arrangement of the low emission indirect
injection diesel engine as per the present invention.
Fig. 3 shows the view that shows aftertreatment system of the low emission indirect
injection diesel engine as per the present invention.
Fig 4 shows the functional schematic block diagram of the EGR controller that provides the
close loop operation of the EGR Circuit.
SUMMARY OF INVENTION:
Low emission indirect injection diesel engine comprising: an indirect injection engine, an after treatment system, an electronic emission control device; said indirect injection diesel engine comprising engine hardware with modifications, with predetermined parameters to optimize low engine out emissions, said engine modifications are to accommodate EGR cooler and proportional EGR valve; to house various sensors to send necessary signals to EGR controller; said after treatment system comprising of a diesel oxidation catalyst and partial particulate trap; said electronic emission control device comprising said EGR

controller, said EGR valve and said EGR cooler such that EGR is cooled through EGR cooler and said EGR controller controls said EGR flow into said engine through EGR
valve.
The after treatment system carbon monoxide (CO) and un-burnt hydrocarbon (HC) is oxidized and particulate matter is trapped and subsequently oxidized and said diesel oxidation catalyst produces sufficient amount of NO2 which results in regeneration of partial particulate trap.
The modifications are in parameters such as compression ratio, combustion chamber, fuel injection timing, fuel delivery. The vacuum pump is connected to alternator to generate vacuum to control vacuum modulator which further regulates vacuum signal to the EGR valve based on the actuation pulses from said EGR controller. The fuel injection pump is provided with a potentiometer which generates an electrical signal which is proportional to load on said engine. The engine coolant is circulated through said EGR cooler in counter flow arrangement, cooled EGR is then supplied through EGR outlet tube which further supplies this gas to the inlet manifold.
The diesel oxidation catalyst is connected just after exhaust manifold in close coupled condition and said particulate oxidation catalyst is connected down stream of said diesel oxidation catalyst. The burning of particulate matter occurs through following two mechanisms such as Low temperature oxidation utilizing the N02 that is generated through the diesel oxidation catalyst and high temperature oxidation occurring at exhaust gas temperatures in excess of- 550 deg. C. The EGR controller is a microprocessor based unit capable of receiving multiple inputs such as Engine coolant temperature, Engine speed, Vehicle speed, Throttle position, Absolute pressure sensor, EGR position feedback.
The said EGR controller is configured with various parameters in terms of look up tables and set points such as Look up tables, Coolant temperature upper & lower set points, Barometric pressure set points. The output of said EGR Controller is EGR valve lift and

MIL lamp activation based on the various inputs received and predetermined configured parameters. The derived valve lift is checked with actual valve lift through feedback signal received from potentiometer on EGR valve and necessary corrective actions are taken. The EGR controller provides diagnostic support functions by P codes and Blink codes through K line.
DETAILED DESCRIPTION:
Low emission indirect injection diesel engine comprises of following three main subsystems.
i) Engine hardware
ii) After treatment system
iii) Electronic emission control device,
The low emission indirect diesel engine comprises of the base engine hardware modified and parameters that are optimized to give low engine out emissions. The engine is modified to accommodate the EGR cooler and proportional EGR valve. In addition, the engine is also modified to house various sensors that give necessary signals to the EGR controller.
The after treatment system comprises of a diesel oxidation catalyst and partial particulate trap. The system comprising of diesel oxidation catalyst and the partial PM filter is optimized in such a way that carbon monoxide (CO) & unburnt hydrocarbon (HC) is oxidized & the particulate matter is trapped & subsequently oxidized. In addition to this. the diesel oxidation catalyst produces sufficient amount of NO2 which results in regeneration of partial particulate trap.
The EGR control system comprises of an EGR controller & EGR metering valve. The recirculated exhaust gas is cooled through EGR cooler. The EGR controller controls the EGR flow into the engine through EGR control valve.
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting the same.

As shown in fig.l, the low emission indirect injection diesel engine is basically an IDI engine (11) which is modified suitably for -
i) Reducing engine out emissions
ii) To incorporate the hardware that is essential to reduce the emissions further.
The first set of modifications comprise of modifications in the base engine parameters such as compression ratio, combustion chamber, fuel injection timing, fuel delivery etc.
The second set of modifications include additions of sensors and actuators for exhaust gas recirculation system and controller for the same. One of the hardware changes that is visible in fig.l is alternator with vacuum pump (12) The vacuum pump connected to the alternator generates the vacuum which is supplied to the vacuum modulator (13). In addition, the alternator also provides engine speed signal. The vacuum modulator regulates the vacuum signal to the EGR valve based on the actuation pulses from EGR controller. The fuel injection pump (15) is provided with a potentiometer (14) which generates an electrical signal which is proportional to the load on the engine.
Fig. 2 shows the EGR system for low emission indirect injection diesel engine. The EGR system comprises of an EGR cooler (21) which is mounted on the engine with the help of bracket. The size of the EGR cooler is decided in such a way that the exhaust gases that are fed into the engine get cooled upto the extent which does not cause any increase in NOx emissions. Further, the system comprises of an EGR inlet tube (22) which carries the exhaust gas from the exhaust manifold (23) to the EGR valve (24). EGR cooler is mounted just at the outlet of the EGR valve. Engine coolant is circulated through the EGR cooler in counter flow arrangement. The cooled EGR is then supplied through EGR outlet tube (25) which further supplies this gas to the inlet manifold (26). Both, the inlet & outlet EGR tubes have flexible bellows which provides the flexibility.
Fig. 3 shows the after treatment system of the low emission diesel engine. The after treatment system comprises of a diesel oxidation catalyst (31) which is connected just after

the exhaust manifold (23) in close coupled condition. The particulate oxidation catalyst (32) is connected down stream of the diesel oxidation catalyst. The oxidation catalyst oxidizes the carbon monoxide (CO) & unburnt hydrocarbons (HC). In addition, the diesel oxidation catalyst also converts NO into N02. The particulate oxidation catalyst initially stores the particulate matter on its surface and subsequently burns it. This process is called as regeneration. The regeneration happens continuously during vehicle operation. The burning of particulate matter occurs through following two mechanisms. -
i) Low temperature oxidation utilizing the N02 that is generated through the
diesel oxidation catalyst.
ii) High temperature oxidation. This oxidation occurs at exhaust gas temperatures in excess of ~ 550 deg. C.
The sizes of the diesel oxidation catalyst, particulate oxidation catalyst are decided based on base engine out emissions and the extent of conversion required. The after treatment system comprising of diesel oxidation catalyst (31) & particulate oxidation catalyst (32) is optimized in such a way that it generates sufficient N02 which is essential for regeneration of the particulate oxidation catalyst.
As shown in fig.4, the electronic EGR controller (41) is a microprocessor based unit capable of receiving multiple inputs (42). The EGR controller receives following inputs -
i) Engine coolant temperature
ii) Engine speed
iii) Vehicle speed
iv) Throttle position
v) Absolute pressure sensor
vi) EGR position feedback
In addition to above inputs, the controller is programmed with various parameters (43) in terms of look up tables and set points. These are -
i) Look up tables
ii) Coolant temperature upper & lower set points

iii) Barometric pressure set points
Based on the various inputs received and the programmed parameters, the EGR controller decides following output actions (44) -
i) EGR valve lift
ii) MIL lamp activation
The derived valve lift is checked with actual valve lift through feedback signal (45) received from the potentiometer on EGR valve and necessary corrective actions are taken to match actual EGR valve lift with the calculated valve lift. In addition, the controller also provides diagnostic support functions (46) by P codes & Blink codes through K line.
The present invention is unique because the combination tried is Indirect diesel engine, Cooled Progressive Mapped Exhaust gas recirculation and Self regenerating Particulate filter is inventory attempt. In totality, the package has been optimized for lower pollutions compliance to the stringent emission norms.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

WE CLAIM:
1. Low emission indirect injection diesel engine comprising
an indirect injection engine, an after treatment system, an electronic emission control
device;
said indirect injection diesel engine comprising engine hardware with modifications, with
predetermined parameters to optimize low engine out emissions,
said engine modifications are to accommodate EGR cooler and proportional EGR valve; to
house various sensors to send necessary signals to EGR controller;
said after treatment system comprising of a diesel oxidation catalyst and partial particulate
trap;
said electronic emission control device comprising said EGR controller, said EGR valve
and said EGR cooler such that EGR is cooled through EGR cooler and said EGR controller
controls said EGR flow into said engine through EGR valve.
2. The system as claimed in Claim 1 wherein, in said after treatment system carbon monoxide (CO) and un-burnt hydrocarbon (HC) is oxidized and particulate matter is trapped and subsequently oxidized and said diesel oxidation catalyst produces sufficient amount of NO2 which results in regeneration of partial particulate trap.
3. The system as claimed in Claim 1 wherein, said modifications are in parameters such as compression ratio, combustion chamber, fuel injection timing, fuel delivery.
4. The system as claimed in Claim 1 wherein, a vacuum pump is connected to alternator to generate vacuum to control vacuum modulator which further regulates vacuum signal to the EGR valve based on the actuation pulses from said EGR controller.
5. The system as claimed in Claim 1 wherein fuel injection pump is provided with a potentiometer which generates an electrical signal which is proportional to load on said engine.

6. The system as claimed in Claim 1 wherein engine coolant is circulated through said EGR cooler in counter flow arrangement, cooled EGR is then supplied through EGR outlet tube which further supplies this gas to the inlet manifold.
7. The system as claimed in Claim 1 wherein said diesel oxidation catalyst is connected just after exhaust manifold in close coupled condition and said particulate oxidation catalyst is connected down stream of said diesel oxidation catalyst.
8. The system as claimed in Claim 1 wherein said burning of particulate matter occurs through following two mechanisms such as Low temperature oxidation utilizing the N02 that is generated through the diesel oxidation catalyst and high temperature oxidation occurring at exhaust gas temperatures in excess of- 550 deg. C.
9. The system as claimed in Claim 1 wherein said EGR controller is a microprocessor based unit capable of receiving multiple inputs such as Engine coolant temperature, Engine speed, Vehicle speed, Throttle position. Absolute pressure sensor, EGR position feedback.

10. The system as claimed in Claim 1 wherein said EGR controller is configured with various parameters in terms of look up tables and set points such as Look up tables, Coolant temperature upper & lower set points, Barometric pressure set points.
11. The system as claimed in Claims 9 and 10 wherein output of said EGR Controller is EGR valve lift and MIL lamp activation based on the various inputs received and predetermined configured parameters.
12. The system as claimed in Claim 1 wherein, derived valve lift is checked with actual valve lift through feedback signal received from potentiometer on EGR valve and necessary corrective actions are taken.

13. The system as claimed in Claim I wherein, said EGR controller provides diagnostic support functions by P codes and Blink codes through K line.