FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
An Arrangement for improved cold start in diesel engines


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. Chinmayananda Khandai, Mr Amar Bakare
an 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 device to improve cold starting performance of diesel engines. More particularly, it relates to add on device that can also be fitted on existing engines.
BACKGROUND OF THE INVENTION
Diesel engines are known for high fuel efficiency, durability and high torque. Since it's inception it has remained unbeatable in terms of thermal efficiency. However when it comes to cold starting at sub zero temperatures, diesel engines superiority over spark ignition engines fades away. It's the method of igniting the air fuel mixture that plays a major role in cold starting. In diesel engines fuel is made to self ignite rather than positively ignited, since ignition of diesel largely depends upon the air temperature at the time of injection. So at low ambient temperature diesel engine starting becomes difficult.
To aid engine starting the generally followed practice is to heat up the intake air by means of an electric heater drawing power from a battery. As ambient temperature goes down, heating requirement goes up, thus demand on battery goes up. However as temperature goes down battery output also goes down. Because of this contradictory condition demand on low temperature battery performance and battery size requirement goes up. Present invention addresses these two contradictory issues by retaining the heat in the system, there by reduces demand on battery performance and size.
PRIOR ART:
Traditionally for easy cold starting of diesel engines Electrical heating of charge air has been used, as sited in following two patents
The patent by Navalon Carretero, Herminio et al (Application No. US2003728099A, Filed:20031202 , Published: 20040914) describes about Electrical resistances to carry


out heating of air necessary for the combustion process of an engine, each of said resistance being in continuous tape form, with a pronounced coiled trajectory so that the resistance is distributed uniformly in an orifice for the passage of air established in a support and has its larger- faces located in imaginary planes parallel to the axis of said orifice so that the electrical resistance presents its front rim to the passage of the air with a minimum loss of head, while presenting a wide contact surface to the air.
The patent by Bern (Application No. EP2002250A, Filed: 20020114, Published:
20041027)
describes a Cold start arrangement for automobile diesel engine with electrical
heating device arranged in the intake air flow path to heat up charge air for easy cold
staring. The patents talks about various possible configurations to achieve this
objective.
However, these patents don't deal with, preserving already heated up gas by the heater to reduce energy wastage. The present invention primarily aims at re¬circulating hot gasses in the system to facilitate cold starting.
OBJECTS OF INVENTION
• The main objective of this invention is to preserve already heated up air by re¬circulating it in the system, thereby, reducing the demand on the battery for extra energy. So that battery size can be reduced.
• Yet another objective of the present invention is to achieve faster cold starting at sub zero temperatures.
• Yet another objective is to have an add-on device on any existing vehicle.
• Yet another objective is to improve cold starting with low incremental cost.


SUMMARY OF INVENTION
Diesel engine cold starting is generally added by heating up the intake air by means of an electric heater drawing power from a battery. As ambient temperature goes down, heating requirement goes up, thus demand on battery goes up. However as temperature goes down battery output also goes down. Because of this contradictory condition demand on low temperature performance of battery and battery size requirement goes up. More over during cranking engine does not start immediately. But during this process already heated up air is expelled from the engine due to the pumping action. Thus loosing precious heat produced at the cost of battery at low temperature.
Present invention addresses above contradictory issues by re-circulating the hot gasses from the engine exhaust to the engine inlet, thereby reducing the heating requirement. And as soon as engine starts this process stops
DESCRIPTION OF PREFFERED EMBODIMENTS
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
The sketches showing details of the arrangement of components for an arrangement to
improve cold starting in diesel engine.
Figure 1 shows the constructional details of the Engine with all its accessories in
normal operation (i.e. Exhaust butterfly in open state and EGR valve closed state).
Figure 2 shows the schematic arrangement of components Engine with all its
accessories with cold starting mechanism in active state (i.e. Exhaust butterfly in
closed state and EGR valve open state).
The present invention requires following arrangement


• A restriction to increase exhaust back pressure either by means of closing a
butterfly valve or by means of closing the vanes of a VGT. Butterfly valves
are generally present in the exhaust system for Exhaust braking.
• An air by pass path connecting exhaust manifold and intake manifold, with a
valve present in between to control the flow. This arrangement is also very
common on modern diesel engines as EGR flow path.
Generally above two arrangements are present on most; of the vehicle. So can be used directly to serve the purpose of cold starting with minor modifications in the in the vacuum circuit. However it will not affect the normal running of the engine once the engine is started as the cold starting logic will get de-activated as soon as engine is started.
The system functions as follows with vacuum operated EGR valve and Exhaust butterfly valve.
1. During cranking engine (1) starts revolving it drives the vacuum pump (2) and
produces vacuum.
2. This vacuum is supplied to a vacuum modulator (3). Which is activated by
electrical signal from starter motor (4).
3. Modulator directs this vacuum signal (5, 6) to open the EGR valve (7) and
close VGT vanes or exhaust butterfly valve (8) simultaneously.
4. As engine revolves it starts pumping action by taking hot air (heated by the
manifold heater (9)) during suction and throwing out this hot air to the exhaust
(10).
5. As the exhaust flow path is closed due to closing butterfly (8) or VGT vanes,
exhaust pressure increase. Now the only path available for the gasses to flow is
the by-pass path (i.e. EGR flow path(7)).
6. So this hot air enters in to the intake manifold(ll) just before the electrical
manifold heater. As a result of this re-circulating hot gas the combustion

chamber gets heated up. So further heat loss from hot gas to cylinder walls reduces. So with every passing second the chances of engine starting increases as the in coming air remains hotter and hotter. This re-circulation process continues as long as engine is being cranked.
7. As the air remains fresh as long as engine does not fire so does not affect the starting of the engine. Once the engine fires oxygen in the air gets used up. But at the same time cranking action also stops as the engine has started. Thus allowing fresh air from out side to come in and sustain engine firing.
8. Cold starting vacuum circuit comes in to action as long as engine is being cranked. The moment engine(l) starts, driver stops cranking, so signal from stator motor(4) to modulator(3) stops. This shuts down the vacuum supply to exhaust butterfly(8) and EGR valve(7). Thus deactivating this circuit. Cold starting vacuum circuit operates in parallel to the main vacuum circuit to operate EGR valve(7) and Exhaust brake(8). Thus does not interfere with the normal engine operation.
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.
Dated this 30th day of March 2009
TATA MOTORS LIMITED By their Agent & Attorney

Karuna Goleria of DePENNING & DePENNING
30 MAR 2009