View source for Circle L engine

{{no footnotes|date=April 2019}}
{{Infobox automobile engine
| name          = Circle L engine
| image         = 
| manufacturer  = [[GM Powertrain Poland]]
| aka           = Isuzu 4EE2
| production    = 
| predecessor   = 
| successor     = [[GM Medium Diesel engine|MDE engine]]
| configuration = [[Inline-4]]
| displacement  = {{cvt|1.686|L|cc cuin|adj=ri1|sigfig=4}}
| bore          = {{convert|79|mm|in|2|abbr=on}}
| stroke        = {{convert|86|mm|in|2|abbr=on}}
| block         = 
| head          = [[Aluminium alloy]]
| valvetrain    = [[DOHC]]
| compression   = 16.5:1, 18.2:1, 18.4:1
| turbocharger  = [[Mitsubishi]] TD025 [[Variable-geometry turbocharger|variable-geometry]]
| fuelsystem    = [[Common rail]] [[Fuel injection#Direct injection systems|direct injection]]
| management    = [[Denso]] or [[Robert Bosch GmbH|Bosch]]
| fueltype      = [[Diesel fuel|Diesel]]
| oilsystem     = [[Wet sump]]
| coolingsystem = [[Radiator (engine cooling)|Water-cooled]]
| power         = {{cvt|65-130|PS|kW|0}}
| specpower     = 
| torque        = {{cvt|130-300|Nm|lbft|0}}
| length        = 
| emissions control = [[Exhaust gas recirculation|EGR]]
| emissions level = [[European emission standards|Euro 3, 4 & 5]]
| weight        = 
}}

The '''Circle L''', originally the '''Isuzu 4EE2''', is an [[automobile]] engine produced by [[GM Powertrain Poland]] in [[Poland]]. It is a {{cvt|1.686|L|cc cuin|adj=ri1|sigfig=4}} [[Straight-four engine|inline-four]] [[Multi-valve|16-valve]] [[Turbocharger|turbocharged]] [[diesel engine]] designed by [[Isuzu]] as part of their E-family of compact diesel engines. The engine was produced in [[Tychy]], [[Poland]] by Isuzu Motors Polska (later GM Powertrain Poland) for use in [[Opel]], [[Vauxhall Motors|Vauxhall]], [[Chevrolet]], and [[Honda]] vehicles.

==History==
In the late nineties the Japanese company [[Isuzu]], which was known for the efficiency of its diesel engines, collaborated with [[General Motors]] on a new diesel engine for the European market for [[Opel]] and [[Vauxhall Motors|Vauxhall]]. For this purpose it opened a new plant in the city of [[Tychy]], in Poland, called Isuzu Motor Polska. The engine blocks were supplied from Japan.<ref name=am-2017>{{cite web |url=https://www.automaniac.org/blog/14/popular-engines-isuzu-1.7-4ee2 |title=Popular engines: Isuzu 1.7 4EE2 |date=March 23, 2017 |website=Auto Maniac |access-date=20 October 2023}}</ref> By May 2004, after about five years in production, Isuzu Motors Polska had built one million 4EE2 engines.<ref>{{cite press release | url = http://www.isuzu.co.jp/world/press/2004/p_0524.html | archiveurl=https://web.archive.org/web/20110522150428/http://www.isuzu.co.jp/world/press/2004/p_0524.html | archivedate=2011-05-22 | title = 1-millionth Diesel Engines Built at Isuzu Polish Engine Plant, ISPOL | publisher = Isuzu Motors Limited | date = 2004-05-24 }}</ref>

At the time the engine was developed, GM owned a 49% share of Isuzu, but later dissolved its stake and reacquired a 12% share for US$80&nbsp;million in exchange for exclusive rights to what they named the Circle L engine.<ref>{{cite news |url=https://www.wardsauto.com/news-analysis/isuzus-turnaround |title=Isuzu's Turnaround |last=Zachary | first = Katherine |date=June 1, 2003 |work=Wards Auto |access-date=20 October 2023}}</ref>

==Characteristics==
For reasons of economy, GM and Isuzu chose not to make an engine from scratch, but rather evolved the new engine from an existing base. Thus, the [[List of Isuzu engines#4EE1|Isuzu 4EE1]] 1.7-liter was chosen and developed into the 4EE2 engine, later renamed the "Circle L" family of engines after General Motors took over the rights to the design.

The engine kept the dimensions of the 1.7 4EE1. The main differences are in the DOHC [[camshaft]]s and [[Fuel injection#Direct injection systems|direct injection]].<ref name=am-2017/> The first engines mounted a simple direct injection and met the [[Euro 3]] standard, while the later engines met [[Euro 4]] and used [[common rail]] injection technology. The 1.7 Circle L common rail engines were the first common rail engines used in Opels.

60 percent of the components for the production of the engines at Isuzu Motor Polska come from Germany, as well as the [[aluminium alloy]] for the manufacture of the cylinder head. The Polish plant was responsible for the construction and the development of the valvetrain. The block, however, arrived in Tychy already built by the Isuzu factory in Hokkaido, Japan.

===4EE2===
The 4EE2 produces {{cvt|75|PS|kW hp|0}} at 4400&nbsp;rpm and {{cvt|165|Nm|lbft|0}} at 1800&nbsp;rpm.

Applications:
* [[Opel Corsa]]
* [[Opel Meriva]]
* [[Opel Astra]]
* [[Opel Zafira]]
* [[Opel Vectra]]
* Cummins MerCruiser Recreational Sterndrive, Inboard or Jet (Boat Engine)

==Circle L (Y17)==
These engines were particularly important for Opel since they were fitted to their best-selling models in a period in which diesel engines became extremely popular. The Circle L engines were then integrated into the Ecotec family of engines, later becoming part of the Ecoflex family.

The 1.7-liter engine was offered in six main variants by Opel/Vauxhall, whose characteristics and applications are described below.

===Y17DT===
The abbreviation Y17DT identifies the first 4EE2 engine when installed in Opels; it is a Euro 3 engine with a compression ratio of 18.4:1. The unit has [[Denso]] engine management, as in most Circle L engines. A Mitsubishi TD025 turbocharger is fitted, as is an [[exhaust gas recirculation]] system. The Y17DT reaches {{cvt|75|PS|kW hp|0}} at 4400&nbsp;rpm, with a torque of {{cvt|165|Nm|lbft|0}} between 1800 and 3000&nbsp;rpm. This engine was fitted in:

*Opel Corsa C 1.7 DTI 16V 75 HP (2000-03);
*Opel Combo C 1.7 DTI 16V (2002-04);
*Opel Astra G 1.7 DTI 16V (1999-2003);
*Opel Meriva 1.7 16V DTI (2003-05);

===Y17DTL===

The engine Y17DTL is a reduced power variant of the Y17DT, to which it differs in the absence of an intercooler. Maximum power is reduced to {{convert|65|PS|kW hp|0|abbr=on}} at 4400 rpm, and maximum torque to {{convert|130|Nm|lbft|0|abbr=on}} between 2000 and 3000 rpm. This engine, also Euro 3, was fitted in:

*Opel Corsa C 1.7 16V 65 HP (2000-03);
*Opel Combo C 1.7 DI 16V (2002-04);

===Z17DTL===

The engine Z17DTL was one of the first common rail [[turbo-diesel engine]]s used as a "CDTi" badge by Opel. With a turbocharger and a compression ratio of 18.4:1, it can reach the maximum power of {{convert|80|PS|kW hp|0|abbr=on}} at 4400 rpm, with a maximum torque of {{convert|170|Nm|lbft|0|abbr=on}} at 1800 rpm. It was fitted in:

* Opel Astra G 1.7 16V CDTI (2003-04)
* Opel Astra H 1.7 CDTI (2004- 05)

===Z17DT===

The engine Z17DT was one of the first common rail turbo diesel engines used as a "CDTi" badge by Opel. With a [[variable-geometry turbocharger]] and a compression ratio of 18.4:1, can reach the maximum power of {{convert|101|PS|kW hp|0|abbr=on}} at 4400 rpm, with a maximum torque of {{convert|240|Nm|lbft|0|abbr=on}} at 2300&nbsp;rpm. It was fitted in:

*Opel Corsa C 1.7 16V CDTI 101CV (2003-06);
*Opel Meriva A 1.7 CDTi 16v 101CV (2003-05);

This engine meets the Euro 4 directive.

===Z17DTH and A17DT===

This motor is similar to the one signed Z17DT it replaces, and features a number of minor improvements. The power is unchanged at {{convert|101|PS|kW hp|0|abbr=on}} at 4400 rpm, but the torque increases to {{convert|260|Nm|lbft|0|abbr=on}} at 2300&nbsp;rpm. It was fitted in

*Opel Meriva A 1.7 CDTI A (2005-10), 
*Opel Astra H 1.7 CDTI (2004-08),
*Opel Combo C 1.7 CDTI (2004-2010).
*Opel Corsa C 1.7 CDTI (2003-06)
With the exception of the Opel Astra 1.7 CDTI 16V, this car had a [[Robert Bosch GmbH|Bosch]] [[engine management system]], and the other four models are equipped with a Denso control unit. In more modern versions, introduced in 2010, this engine delivers {{convert|100|PS|kW hp|0|abbr=on}} of maximum power at 4000&nbsp;rpm, while maximum torque is always {{convert|260|Nm|lbft|0|abbr=on}}, but delivered between 1,700 and 2,550&nbsp;rpm. In this configuration, this engine has been fitted to:

*Opel Meriva B 1.7 CDTI (2010-13)

===Z17DTR and A17DTR===

These are more powerful variants (but not the most powerful) of the Circle L engines. They also meet the Euro 4 standard, but feature a slightly lower compression ratio of 18.2:1. As in all Euro 4 engine an exhaust gas recirculation system is present. The maximum power reaches {{convert|125|PS|kW hp|0|abbr=on}} at 4000&nbsp;rpm, with a peak torque of {{convert|280|Nm|lbft|0|abbr=on}} between 2000 and 2700&nbsp;rpm.

This engine was fitted in:

*Opel Corsa D 1.7 CDTI 16V 125hp (2006-11);
*Opel Corsa D GSi 1.7 CDTI ( 2007 -11);
*Opel Meriva 1.7 CDTI 16V 125hp (2006-10);
*Opel Astra 1.7 16V 5p CDTI 125hp (2007-09);
*Opel Astra H SW 1.7 CDTI 16V 125hp (2007-10);
*Opel Astra GTC 1.7 CDTI 16V 125hp (2007- 11 ). 

The abbreviation A17DTR identifies the [[Euro 5]] variant, which has otherwise identical features and is fitted in:

*Opel Zafira B 1.7 CDTI 16V 125hp ( 2009 -14);
*Opel Astra J 1.7 CDTI 125hp (2010-11). 


===A17DTS===

In 2010 the engine A17DTR was developed into the A17DTS: here the engine power has been increased to {{convert|130|PS|kW hp|0|abbr=on}} at 4000&nbsp;rpm, while the maximum torque is increased to {{convert|300|Nm|lbft|0|abbr=on}} between 2000 and 2500&nbsp;rpm. This variant has been fitted in:

*Opel Corsa D 1.7 CDTI (2011-13);
*Opel Astra J 1.7 CDTI 130cv (2011-14);
*Opel Meriva B 1.7 CDTI 130cv (2010-13);
*Opel Mokka 1.7 CDTI ( 2012 -15);
*Chevrolet Cruze 1.7 VCDi (2012-14);
*Chevrolet Trax 1.7 D ( 2013 - 15 ).

===Z17DTJ and A17DTJ===

This engine was the basis for the 1.7 Ecoflex: Maximum power reaches {{convert|110|PS|kW hp|0|abbr=on}} at 3800&nbsp;rpm, with a maximum torque of {{convert|260|Nm|lbft|0|abbr=on}} at 2000&nbsp;rpm.

It is fitted in:

*Opel Astra H 1.7 CDTI 16v 110 bhp (2007-09);
*Opel Astra J 1.7 CDTI 16v 110 bhp (2010-15);
*Opel Astra GTC H / SW 1.7 CDTI 16v 110 bhp (2007-10 );
*Opel Zafira B 1.7 CDTi 16v 110HP (2007-08).

===A17DTC and A17DTE===

This is the second diesel engine in the Opel engine range to be included in the EcoFlex range (the first was a 1.3 Multijet engine from Fiat). Introduced in 2008, is based on the Z17DTJ engine developed simultaneously, and is characterized by a reduction of friction of the moving parts in order to optimize the [[thermal efficiency]] and meet the stricter Euro 5 standard. Outputs are identical to those of the Z17DTJ. It is fitted in:

*Opel Meriva B 1.7 CDTi 16v 110HP (from 2010);
*Opel Zafira B 1.7 CDTi 16v 110HP (2008-14);
*Opel Astra J 1.7 CDTI 16v 110HP (2010-14).

==Honda==
The Honda version features high-pressure [[common rail|common rail direct injection]], while Opel's ''4EE2'' unit uses low-pressure DI. Honda's purchase of Isuzu engines was reciprocated by GM's purchase of the ''[[Honda J engine|J35A3]]'' [[V6]]. As per Honda, who called this engine CTDi, certain Honda parts were used, such as the "fuel filter and accelerator position sensor."<ref name=CTDi03>{{cite press release | url = https://hondanews.eu/eu/en/cars/media/pressreleases/34257/civic-ctdi | archiveurl = https://web.archive.org/web/20241130132708/https://hondanews.eu/eu/en/cars/media/pressreleases/34257/civic-ctdi | archivedate = 2024-11-30 | title = Civic CTDi | date = 2003-09-01 | publisher = Honda Motor Europe Ltd. | work = European Media Newsroom }}</ref> Maximum power is {{cvt|100|PS|kW hp|0}} at 4400&nbsp;rpm, with torque of {{cvt|220|Nm|lbft|0}} at 1800&nbsp;rpm.<ref name=CTDi03/> Only used in the Civic for the European market, the engines were built by Isuzu Motors Polska in their Polish plant.<ref name=CTDi01>{{cite press release | url = https://global.honda/en/newsroom/news/2001/c010518-eng.html | archiveurl = https://web.archive.org/web/20250611005641/https://global.honda/en/newsroom/news/2001/c010518-eng.html | archivedate = 2025-06-11 | title = European Civic to be Equipped with Isuzu-designed Diesel Engine - Honda Further Announces Development of New-Generation 2-liter Class Diesel Engine | date = 2001-05-18 | publisher = Honda Motor Co., Ltd. | work = Newsroom }}</ref>

Applications:
* [[Honda Civic (seventh generation)]] (Europe)

==See also==
* [[List of GM engines]]
* [[DMAX (engines)|DMAX]]
* [[Honda N engine|Honda N series diesel engine]]

==References==
{{reflist}}

==External links==
* [http://www.cmdmarine.com/PDFs/4081824_1104.pdf Mercruiser Brochure]
* [http://www.cmdmarine.com/PDFs/4081946_1105.pdf Mercruiser Brochure]
* [http://www.cmdmarine.com/PDFs/4081931_1104.pdf Mercruiser Brochure]
* [http://www.isuzu.co.jp/world/press/2000/p_1018.html Mercruiser/Isuzu Venture Article] {{Webarchive|url=https://web.archive.org/web/20060721021905/http://www.isuzu.co.jp/world/press/2000/p_1018.html |date=2006-07-21 }}

{{Honda}}{{Honda automotive engine timeline (2000-present)}}{{GM late engine timeline}}

[[Category:DMAX engines|Circle L]]
[[Category:Isuzu]]
[[Category:Honda engines]]
[[Category:Diesel engines by model]]
[[Category:Straight-four engines]]