Diesel Vehicles - Revision history

81.105.118.128: /* Types of diesel engines */

2009-08-16T23:04:41Z

Types of diesel engines

← Older revision		Revision as of 23:04, 16 August 2009
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	==Types of diesel engines==		==Types of diesel engines==
	There are two classes of diesel (and gasoline) engines: two-stroke and four-stroke.		There are two classes of diesel (and gasoline) engines: two-stroke and four-stroke.
	Most diesels generally use the [[four-stroke]] cycle, with some larger diesels operating on the [[two-stroke]] cycle, mainly the huge engines in in ships (see also Nissan UD3, UD4 and UD6 engine series).		Most diesels generally use the [[four-stroke]] cycle, with some larger diesels operating on the [[two-stroke]] cycle, mainly the huge engines in ships (see also Nissan UD3, UD4 and UD6 engine series).

	Normally, banks of [[cylinder]]s are used in multiples of two, although any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration. The [[inline-6]] is the most prolific in medium- to heavy-duty engines, though the [[V8]] and [[straight-4]] are also common.		Normally, banks of [[cylinder]]s are used in multiples of two, although any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration. The [[inline-6]] is the most prolific in medium- to heavy-duty engines, though the [[V8]] and [[straight-4]] are also common.

Mckinneym: /* Advantages and disadvantages versus spark-ignition engines */

2006-07-17T16:51:35Z

Advantages and disadvantages versus spark-ignition engines

← Older revision		Revision as of 16:51, 17 July 2006
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	Diesel engines produce very little carbon monoxide as they burn the fuel in excess air even at full load, at which point the quantity of fuel injected per cycle is still about 50% lean of stochiometric. However, they can produce black soot from their exhaust, consisting of unburned carbon compounds. This is often caused by worn injectors, which do not atomize the fuel sufficiently, or a faulty engine management system which allows more fuel to be injected than can be burned completely in the available time - the full load limit of a diesel engine in normal service is defined by the "black smoke limit", beyond which point the fuel cannot be completely combusted; as the "black smoke limit" is still considerably lean of stoichiometric it is possible to obtain more power by exceeding it, but the resultant inefficient combustion means that the extra power comes at the price of reduced combustion efficiency, high fuel consumption and dense clouds of smoke, so this is only done in specialised applications such as tractor pulling where these disadvantages are of little concern. Particles of the size normally called PM10 (particles of 10 micrometres or smaller) have been implicated in health problems, especially in cities. Modern diesel engines catch the soot in a particle filter , which when saturated is automatically regenerated by burning the particles. Other problems associated with the exhaust gases (nitrogen oxides, sulfur oxides) can be mitigated with further investment and equipment; some diesel cars now have catalytic converters in the exhaust.		Diesel engines produce very little carbon monoxide as they burn the fuel in excess air even at full load, at which point the quantity of fuel injected per cycle is still about 50% lean of stochiometric. However, they can produce black soot from their exhaust, consisting of unburned carbon compounds. This is often caused by worn injectors, which do not atomize the fuel sufficiently, or a faulty engine management system which allows more fuel to be injected than can be burned completely in the available time - the full load limit of a diesel engine in normal service is defined by the "black smoke limit", beyond which point the fuel cannot be completely combusted; as the "black smoke limit" is still considerably lean of stoichiometric it is possible to obtain more power by exceeding it, but the resultant inefficient combustion means that the extra power comes at the price of reduced combustion efficiency, high fuel consumption and dense clouds of smoke, so this is only done in specialised applications such as tractor pulling where these disadvantages are of little concern. Particles of the size normally called PM10 (particles of 10 micrometres or smaller) have been implicated in health problems, especially in cities. Modern diesel engines catch the soot in a particle filter , which when saturated is automatically regenerated by burning the particles. Other problems associated with the exhaust gases (nitrogen oxides, sulfur oxides) can be mitigated with further investment and equipment; some diesel cars now have catalytic converters in the exhaust.

	For commercial uses requiring towing, load carrying and other tractive tasks, diesel engines tend to have more desirable [[torque]] characterstics. Diesel engines tend to have their torque peak quite low in their speed range (usually between 1600-2000 rpm for a small-capacity unit, lower for a larger engine used in a ~~[[lorry]] or [[~~truck]]). This provides smoother control over heavy loads when starting from rest, and crucially allows the diesel engine to be given higher loads at low speeds than a gasoline engine, which makes them much more economical for these applications. This characteristic is not so desirable in private cars, so most modern diesels used in such vehicles use electronic control, variable geometery [[turbocharger]]s and shorter piston strokes to achieve a wider spread of torque over the engine's speed range, typically peaking at around 2,500-3000 rpm.		For commercial uses requiring towing, load carrying and other tractive tasks, diesel engines tend to have more desirable [[torque]] characterstics. Diesel engines tend to have their torque peak quite low in their speed range (usually between 1600-2000 rpm for a small-capacity unit, lower for a larger engine used in a truck). This provides smoother control over heavy loads when starting from rest, and crucially allows the diesel engine to be given higher loads at low speeds than a gasoline engine, which makes them much more economical for these applications. This characteristic is not so desirable in private cars, so most modern diesels used in such vehicles use electronic control, variable geometery [[turbocharger]]s and shorter piston strokes to achieve a wider spread of torque over the engine's speed range, typically peaking at around 2,500-3000 rpm.

	As mentioned above, diesel engines tend to have more [[torque]] at lower engine speeds than gasoline engines. However, diesel engines tend to have a narrower [[power band]] than gasoline engines. Naturally-aspirated diesels tend to lack power and torque at the top of their speed range. This narrow band is a reason why a vehicle such as a truck may have a [[transmission]] with as many as 16 or more gears, to allow the engine's power to be used effectively at all speeds. Turbochargers tend to improve power at high engine speeds, and if an intercooler is added, torque tends to improve at lower speeds.		As mentioned above, diesel engines tend to have more [[torque]] at lower engine speeds than gasoline engines. However, diesel engines tend to have a narrower [[power band]] than gasoline engines. Naturally-aspirated diesels tend to lack power and torque at the top of their speed range. This narrow band is a reason why a vehicle such as a truck may have a [[transmission]] with as many as 16 or more gears, to allow the engine's power to be used effectively at all speeds. Turbochargers tend to improve power at high engine speeds, and if an intercooler is added, torque tends to improve at lower speeds.

	The lack of an electrical [[ignition]] system greatly improves the reliability. The high durability of a diesel engine is also due to its overbuilt nature as well as the diesel's combustion cycle, which creates less-violent changes in pressure when compared to a spark-ignition engine, a benefit that is magnified by the lower rotating speeds in diesels. Diesel fuel is a better lubricant than gasoline so is less harmful to the oil film on [[piston ~~ring]]s~~ and [[~~cylinder (engine)\|~~cylinder]] bores; it is routine for diesel engines to cover 250,000 miles or more without a rebuild.		The lack of an electrical ignition system greatly improves the reliability. The high durability of a diesel engine is also due to its overbuilt nature as well as the diesel's combustion cycle, which creates less-violent changes in pressure when compared to a spark-ignition engine, a benefit that is magnified by the lower rotating speeds in diesels. Diesel fuel is a better lubricant than gasoline so is less harmful to the oil film on piston rings and [[cylinder]] bores; it is routine for diesel engines to cover 250,000 miles or more without a rebuild.

	Regular maintenance on a diesel is more costly due to factors such as the larger volume of oil in the engine, and the fact that fuel filters and water separators need to be serviced more often.		Regular maintenance on a diesel is more costly due to factors such as the larger volume of oil in the engine, and the fact that fuel filters and water separators need to be serviced more often.

Mckinneym at 16:49, 17 July 2006

2006-07-17T16:49:38Z

← Older revision		Revision as of 16:49, 17 July 2006
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	In very cold weather, diesel fuel thickens and increases in viscosity and forms wax crystals or a gel. This can make it difficult for the fuel injector to get fuel into the cylinder in an effective manner, making cold weather starts difficult at times, though recent advances in diesel fuel technology have made these difficulties rare. A commonly applied advance is to electrically heat the fuel filter and fuel lines. Other engines utilize small electric heaters called [[glow plug]]s inside the cylinder to warm the cylinders prior to starting. A small number use resistive grid heaters in the intake manifold to warm the inlet air until the engine reaches operating temperature. Engine block heaters (electric resistive heaters in the engine block) plugged into the utility grid are often used when an engine is shut down for extended periods (more than an hour) in cold weather to reduce startup time and engine wear.		In very cold weather, diesel fuel thickens and increases in viscosity and forms wax crystals or a gel. This can make it difficult for the fuel injector to get fuel into the cylinder in an effective manner, making cold weather starts difficult at times, though recent advances in diesel fuel technology have made these difficulties rare. A commonly applied advance is to electrically heat the fuel filter and fuel lines. Other engines utilize small electric heaters called [[glow plug]]s inside the cylinder to warm the cylinders prior to starting. A small number use resistive grid heaters in the intake manifold to warm the inlet air until the engine reaches operating temperature. Engine block heaters (electric resistive heaters in the engine block) plugged into the utility grid are often used when an engine is shut down for extended periods (more than an hour) in cold weather to reduce startup time and engine wear.

	A vital component of older diesel engine systems was the governor, which limited the speed of the engine by controlling the rate of fuel delivery. Unlike a gasoline engine, the incoming air is not throttled, so the engine would overspeed if this was not done. Older injection systems were driven by a gear system from the engine (and thus supplied fuel only linearly with engine speed). Modern electronically-controlled engines apply similar control to gasoline engines and limit the maximum RPM through the engine control module ([[ECM]]) or engine control unit ([[ECU]]) the engine-mounted "computer". The ECM/[[ECU]] receives an engine speed signal from a sensor and then using its algorithms and look-up calibration tables stored in the ECM/ECU, it controls the amount of fuel and its timing (the "start of injection") through electric or hydraulic actuators to maintain engine speed.		A vital component of older diesel engine systems was the governor, which limited the speed of the engine by controlling the rate of fuel delivery. Unlike a gasoline engine, the incoming air is not throttled, so the engine would overspeed if this was not done. Older injection systems were driven by a gear system from the engine (and thus supplied fuel only linearly with engine speed). Modern electronically-controlled engines apply similar control to gasoline engines and limit the maximum RPM through the engine control module ([[ECM]]) or engine control unit ([[ECU]]) the engine-mounted "computer". The [[ECM]]/[[ECU]] receives an engine speed signal from a sensor and then using its algorithms and look-up calibration tables stored in the [[ECM]]/[[ECU]], it controls the amount of fuel and its timing (the "start of injection") through electric or hydraulic actuators to maintain engine speed.

	Controlling the timing of the '''start of injection''' of fuel into the cylinder is key to minimising the emissions and maximising the fuel economy (efficiency) of the engine. The exact timing of starting this fuel injection into the cylinder is controlled electronically in most of today's modern engines. The timing is usually measured in units of crank angle of the piston before Top Dead Center (TDC). For example, if the [[ECM]]/[[ECU]] initiates fuel injection when the [[piston]] is 10 degrees before TDC, the start of injection or "timing" is said to be 10 deg BTDC. The optimal timing will depend on both the engine design as well as its speed and load.		Controlling the timing of the '''start of injection''' of fuel into the cylinder is key to minimising the emissions and maximising the fuel economy (efficiency) of the engine. The exact timing of starting this fuel injection into the cylinder is controlled electronically in most of today's modern engines. The timing is usually measured in units of crank angle of the piston before Top Dead Center (TDC). For example, if the [[ECM]]/[[ECU]] initiates fuel injection when the [[piston]] is 10 degrees before TDC, the start of injection or "timing" is said to be 10 deg BTDC. The optimal timing will depend on both the engine design as well as its speed and load.

Mckinneym at 16:36, 17 July 2006

2006-07-17T16:36:46Z

← Older revision		Revision as of 16:36, 17 July 2006
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	[[Image:Patent_dieselengine.jpg\|thumb\|180px\|right\|[[Rudolf Diesel]]'s 1893 patent on his engine design]]		[[Image:Patent_dieselengine.jpg\|thumb\|180px\|right\|[[Rudolf Diesel]]'s 1893 patent on his engine design]]

	A diesel vehicle is an automobile or other vehicle that uses a diesel engine for propulsion. The ~~'''diesel~~ engine~~'''~~ is a type of [[internal combustion engine]]; more specifically, it is a compression ignition engine, in which the [[fuel]] is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas, rather than by a separate source of ignition, such as a spark plug, as is the case in the gasoline engine.		A diesel vehicle is an automobile or other vehicle that uses a diesel engine for propulsion. The [[Diesel engine]] is a type of [[internal combustion engine]]; more specifically, it is a compression ignition engine, in which the [[fuel]] is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas, rather than by a separate source of ignition, such as a spark plug, as is the case in the gasoline engine.

	This is known as the diesel cycle, after German engineer [[Rudolf Diesel]], who invented it in 1892 based on the hot bulb engine and received the patent on February 23, 1893. Diesel intended the engine to use a variety of fuels including coal dust. He demonstrated it in the 1900 Exposition Universelle (World's Fair) using peanut oil (see [[biodiesel]]).		This is known as the diesel cycle, after German engineer [[Rudolf Diesel]], who invented it in 1892 based on the hot bulb engine and received the patent on February 23, 1893. Diesel intended the engine to use a variety of fuels including coal dust. He demonstrated it in the 1900 Exposition Universelle (World's Fair) using peanut oil (see [[biodiesel]]).

Mckinneym: /* Types of diesel engines */

2006-07-17T15:07:52Z

Types of diesel engines

← Older revision		Revision as of 15:07, 17 July 2006
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	==Types of diesel engines==		==Types of diesel engines==
	There are two classes of diesel (and gasoline) engines: two-stroke and four-stroke.		There are two classes of diesel (and gasoline) engines: two-stroke and four-stroke.
	Most diesels generally use the [[four-stroke ~~cycle~~]], with some larger diesels operating on the [[two-stroke]] cycle, mainly the huge engines in in ships (see also Nissan UD3, UD4 and UD6 engine series).		Most diesels generally use the [[four-stroke]] cycle, with some larger diesels operating on the [[two-stroke]] cycle, mainly the huge engines in in ships (see also Nissan UD3, UD4 and UD6 engine series).

	Normally, banks of [[cylinder]]s are used in multiples of two, although any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration. The [[inline-6]] is the most prolific in medium- to heavy-duty engines, though the [[V8]] and [[straight-4]] are also common.		Normally, banks of [[cylinder]]s are used in multiples of two, although any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration. The [[inline-6]] is the most prolific in medium- to heavy-duty engines, though the [[V8]] and [[straight-4]] are also common.

Mckinneym: /* Types of diesel engines */

2006-07-17T14:59:44Z

Types of diesel engines

← Older revision		Revision as of 14:59, 17 July 2006
Line 12:		Line 12:

	==Types of diesel engines==		==Types of diesel engines==

	There are two classes of diesel (and gasoline) engines: two-stroke and four-stroke.		There are two classes of diesel (and gasoline) engines: two-stroke and four-stroke.
	Most diesels generally use the [[four-stroke cycle]], with some larger diesels operating on the [[two-stroke ~~cycle~~]], mainly the huge engines in in ships (see also Nissan UD3, UD4 and UD6 engine series).		Most diesels generally use the [[four-stroke cycle]], with some larger diesels operating on the [[two-stroke]] cycle, mainly the huge engines in in ships (see also Nissan UD3, UD4 and UD6 engine series).

	Normally, banks of [[cylinder]]s are used in multiples of two, although any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration. The [[inline-6]] is the most prolific in medium- to heavy-duty engines, though the [[V8]] and [[straight-4]] are also common.		Normally, banks of [[cylinder]]s are used in multiples of two, although any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration. The [[inline-6]] is the most prolific in medium- to heavy-duty engines, though the [[V8]] and [[straight-4]] are also common.

Mckinneym at 14:29, 17 July 2006

2006-07-17T14:29:37Z

← Older revision		Revision as of 14:29, 17 July 2006
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	[[Image:Patent_dieselengine.jpg\|thumb\|180px\|right\|[[Rudolf Diesel]]'s 1893 patent on his engine design]]		[[Image:Patent_dieselengine.jpg\|thumb\|180px\|right\|[[Rudolf Diesel]]'s 1893 patent on his engine design]]

	A diesel vehicle is an automobile or other vehicle that uses a diesel engine for propulsion. The '''diesel engine''' is a type of [[internal combustion engine]]; more specifically, it is a compression ignition engine, in which the [[fuel]] is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas, rather than by a separate source of ignition, such as a spark plug, as is the case in the [[gasoline engine]].		A diesel vehicle is an automobile or other vehicle that uses a diesel engine for propulsion. The '''diesel engine''' is a type of [[internal combustion engine]]; more specifically, it is a compression ignition engine, in which the [[fuel]] is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas, rather than by a separate source of ignition, such as a spark plug, as is the case in the gasoline engine.

	This is known as the diesel cycle, after German engineer [[Rudolf Diesel]], who invented it in 1892 based on the hot bulb engine and received the patent on February 23, 1893. Diesel intended the engine to use a variety of fuels including coal dust. He demonstrated it in the 1900 Exposition Universelle (World's Fair) using peanut oil (see [[biodiesel]]).		This is known as the diesel cycle, after German engineer [[Rudolf Diesel]], who invented it in 1892 based on the hot bulb engine and received the patent on February 23, 1893. Diesel intended the engine to use a variety of fuels including coal dust. He demonstrated it in the 1900 Exposition Universelle (World's Fair) using peanut oil (see [[biodiesel]]).

Mckinneym: /* Fuel injection in diesel engines */

2006-07-17T14:26:15Z

Fuel injection in diesel engines

← Older revision		Revision as of 14:26, 17 July 2006
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	====Distributor pump direct injection====		====Distributor pump direct injection====

	The first incarnations of direct injection diesels used a rotary pump much like indirect injection diesels, however the injectors were mounted in the top of the combustion chamber rather than in a separate pre-combustion chamber. Examples are vehicles such as the Ford Transit and the Austin Rover Maestro and Montego with their Perkins Prima engine. The problem with these vehicles was the harsh noise that they made and particulate (smoke) emissions. This is the reason that ~~in the main~~ this type of engine was limited to commercial vehicles— the notable exceptions being the Maestro, Montego and Fiat Croma passenger cars. Fuel consumption was about fifteen to twenty percent lower than indirect injection diesels, which for some buyers was enough to compensate for the extra noise.		The first incarnations of direct injection diesels used a rotary pump much like indirect injection diesels, however the injectors were mounted in the top of the combustion chamber rather than in a separate pre-combustion chamber. Examples are vehicles such as the Ford Transit and the Austin Rover Maestro and Montego with their Perkins Prima engine. The problem with these vehicles was the harsh noise that they made and particulate (smoke) emissions. This is the reason that this type of engine was limited to commercial vehicles— the notable exceptions being the Maestro, Montego and Fiat Croma passenger cars. Fuel consumption was about fifteen to twenty percent lower than indirect injection diesels, which for some buyers was enough to compensate for the extra noise.

	One of the first small-capacity, mass-produced direct-injection engines that could be called refined was developed by the Rover Group. The '200Tdi' 2.5-litre 4-cylinder turbodiesel (of 111 [[HP]]) was used by [[Land Rover]] in their vehicles from 1989, and the engine used an aluminium cylinder head, [[Robert Bosch GmbH\|Bosch]] two-stage injection and multi-phase [[glow plug]]s to produce a smooth-running and economical engine while still using mechanical fuel injection.		One of the first small-capacity, mass-produced direct-injection engines that could be called refined was developed by the Rover Group. The '200Tdi' 2.5-litre 4-cylinder turbodiesel (of 111 [[HP]]) was used by [[Land Rover]] in their vehicles from 1989, and the engine used an aluminium cylinder head, [[Robert Bosch GmbH\|Bosch]] two-stage injection and multi-phase [[glow plug]]s to produce a smooth-running and economical engine while still using mechanical fuel injection.

205.205.28.3 at 13:59, 17 July 2006

2006-07-17T13:59:28Z

Mckinneym at 11:52, 17 July 2006

2006-07-17T11:52:44Z

← Older revision		Revision as of 11:52, 17 July 2006
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	In very cold weather, diesel fuel thickens and increases in viscosity and forms wax crystals or a gel. This can make it difficult for the fuel injector to get fuel into the cylinder in an effective manner, making cold weather starts difficult at times, though recent advances in diesel fuel technology have made these difficulties rare. A commonly applied advance is to electrically heat the fuel filter and fuel lines. Other engines utilize small electric heaters called [[glow plug]]s inside the cylinder to warm the cylinders prior to starting. A small number use resistive grid heaters in the intake manifold to warm the inlet air until the engine reaches operating temperature. Engine block heaters (electric resistive heaters in the engine block) plugged into the utility grid are often used when an engine is shut down for extended periods (more than an hour) in cold weather to reduce startup time and engine wear.		In very cold weather, diesel fuel thickens and increases in viscosity and forms wax crystals or a gel. This can make it difficult for the fuel injector to get fuel into the cylinder in an effective manner, making cold weather starts difficult at times, though recent advances in diesel fuel technology have made these difficulties rare. A commonly applied advance is to electrically heat the fuel filter and fuel lines. Other engines utilize small electric heaters called [[glow plug]]s inside the cylinder to warm the cylinders prior to starting. A small number use resistive grid heaters in the intake manifold to warm the inlet air until the engine reaches operating temperature. Engine block heaters (electric resistive heaters in the engine block) plugged into the utility grid are often used when an engine is shut down for extended periods (more than an hour) in cold weather to reduce startup time and engine wear.

	A vital component of older diesel engine systems was the governor, which limited the speed of the engine by controlling the rate of fuel delivery. Unlike a gasoline engine, the incoming air is not throttled, so the engine would overspeed if this was not done. Older injection systems were driven by a gear system from the engine (and thus supplied fuel only linearly with engine speed). Modern electronically-controlled engines apply similar control to gasoline engines and limit the maximum RPM through the [[~~electronic control module~~]] ~~(ECM~~) or ~~[[electronic~~ control unit]] ([[ECU]]) - the engine-mounted "computer". The ECM/ECU receives an engine speed signal from a sensor and then using its algorithms and look-up calibration tables stored in the ECM/ECU, it controls the amount of fuel and its timing (the "start of injection") through electric or hydraulic actuators to maintain engine speed.		A vital component of older diesel engine systems was the governor, which limited the speed of the engine by controlling the rate of fuel delivery. Unlike a gasoline engine, the incoming air is not throttled, so the engine would overspeed if this was not done. Older injection systems were driven by a gear system from the engine (and thus supplied fuel only linearly with engine speed). Modern electronically-controlled engines apply similar control to gasoline engines and limit the maximum RPM through the engine control module ([[ECM]]) or engine control unit ([[ECU]]) the engine-mounted "computer". The ECM/[[ECU]] receives an engine speed signal from a sensor and then using its algorithms and look-up calibration tables stored in the ECM/ECU, it controls the amount of fuel and its timing (the "start of injection") through electric or hydraulic actuators to maintain engine speed.

	Controlling the timing of the '''start of injection''' of fuel into the cylinder is key to minimising the [[emissions]] and maximising the [[fuel economy]] (efficiency) of the engine. The exact timing of starting this fuel injection into the cylinder is controlled electronically in most of today's modern engines. The timing is usually measured in units of crank angle of the piston before [[Top Dead Center]] (TDC). For example, if the [[ECM]]/[[ECU]] initiates fuel injection when the [[piston]] is 10 degrees before TDC, the start of injection or "timing" is said to be 10 deg BTDC. The optimal timing will depend on both the engine design as well as its speed and load.		Controlling the timing of the '''start of injection''' of fuel into the cylinder is key to minimising the [[emissions]] and maximising the [[fuel economy]] (efficiency) of the engine. The exact timing of starting this fuel injection into the cylinder is controlled electronically in most of today's modern engines. The timing is usually measured in units of crank angle of the piston before [[Top Dead Center]] (TDC). For example, if the [[ECM]]/[[ECU]] initiates fuel injection when the [[piston]] is 10 degrees before TDC, the start of injection or "timing" is said to be 10 deg BTDC. The optimal timing will depend on both the engine design as well as its speed and load.